texts: Why are callouts of changes in the Flight Mode Annunciator not automated?

texts: With many airlines it seems to be standard that the Pilot Monitoring observes the Flight Mode Annunciator (FMA) and calls out any changes in the autopilot mode displayed on the FMA (I guess to raise awareness to the new or armed flight mode). Why are these announcements not automated (i.e. computer generated voice like the altitude announcements during final approach)?


texts: Can a PPL holder fly family and friends aboard an A380?

texts: Would I be able to fly an A380 with a private pilots license and carry family and friends? I know I can fly the A380 with a PPL.


texts: Why aren't rudder pedals automatic or connected with ailerons to keep the nose of the aircraft coordinated with the turn its entering? Wouldn't this make for an easier and smoother to operate aircraft?


texts: What is the minimum distance allowed between two parallel runways?

texts: Is there an international regulation for this matter or does it differ from one country to another?


texts: Why does enabling engine sync on the MD-80 series trigger the "Master Caution" light?

texts:
I fly in a consumer PC flight simulator. Among my virtual fleet is a fairly faithfully-reproduced MD-83.

One fairly strange detail I noticed is that enabling engine sync (either on N1 or N2) in the overhead, while on the ramp, triggers not just the alert on the annunciator panel, but also the master caution light -- why is this? Engine sync isn't a particularly abnormal condition. Is this just an inaccuracy in the simulator?


texts: What is engine power vs propeller thrust relation?

texts:
Given:

speed 30 knots
engine power 70 hp at 5800 RPM
propeller 3 blades, diameter 14 inch, pitch 17 inch, at 2300 RPM
fluid density 1023 kg/m3

I know that each blade is basically one wing.  Calculating lift is extremely complex; even Navier-Stokes equations will not give an accurate result.
But can I estimate the  thrust this produces, for these values or in general?


texts: Is ATIS information - including identifier - available on the internet?

texts:
According to Section 2-9-1-a of the FAA's Air Traffic Organization Policy, a phonetic letter is assigned to each tower-issued ATIS update.

This information is available on the ATIS VHF frequency for an airport, or via a phone call to a designated ATIS number for the airport.

There is a passing reference on the Wikipedia page to ATIS being available electronically via a service named "D-ATIS", although I've never heard of this.

I'd love to be able to view this information electronically, rather than having to get my VHF handheld, or the plane's radio going and tune it in before flight. The voice system is frequently engaged. If it was available via the internet, it'd be super-easy to access.

Is there a means accessing the ATIS - including the identifier - for a given airport in electronic form via the internet? If so, how?

NOTE: I know it's possible to get METAR reports, but they are typically automatically generated, not manually adjusted by the tower (as ATIS sometimes is), and don't include the phonetic letter designation issued by the tower and required for initial tower contact.


texts: What is the missed approach procedure when initiated below MDA/DA/DH?

texts:
Let's say you continue below the DA/DH on an IAP because you have the APL insight; and of course no lower then 100 ft above TDZE.

Now you arrive and don't see any required visual cues to continue to land.

When would you decide to go missed on an ILS? since you already descended below your DA
If you were to execute a missed procedure below the DA/DH on the same scenario above are you assured obstacle clearance? (my thoughts are no, obstacle clearance is only assured if its executed at the MAP, at or above MDA or DA/DH with a 200ft/nm climb)


texts: Why do I get that funny stomach drop feeling right after takeoff?

texts: Right after take off 1-2 minutes into flight I get this stomach drop "roller coaster" feeling for split second.  It freaks people out thinking they are about to crash!  Why is that??


texts: What does it take to maintain a private pilot certificate?

texts:
What, if any, requirements are there to maintain a private pilot certificate? For example:

Do I have to renew my certificate after a period of time? E.g. annually, 5 years, 10 years
Do I have to receive a minimum number of continued training hours?
Do I have to fly a minimum number of hours?

For instance, say I had enough money/time to go out and start the process of getting a private pilot certificate tomorrow, but I didn't plan to make use of it in the foreseeable future, would it cost me more in time and money than if I waited until I had plans to use it?

This is assuming I live and fly in the USA.

Related Question:
How much, generally speaking, does it cost to learn how to fly?

Edit:
Note I understand the safety aspect of not practicing and "getting rusty", for lack of a better term on my part, and that practically a certain amount of retraining would be required (though it seems that it is not legally required). The retraining is not mandated and I would need to retrain until I felt proficient enough technically and practically. Retraining would include familiarizing myself with the controls, instruments, radio, physics, etc.

My main concern was that (a) at some point I my certificate would expire and I would have to go through the process again, making the initial effort practically useless, (b) that I may have to pay a significant amount of money to keep the certificate from expiring, or (c) that I would have to commit to a certain number of hours (instructed or solo) per year to keep the certificate.


texts: Do lights on wingtips change color at different times of the day?

texts:
I have gone through this post which explained me why there are red lights turned on the plane but I doubt with the color code whether it's only during the environment specific conditions or its indication that it is relaying coordinates?

Every time one thing caught my attention during my flight journey. During the specific time of the day the lights on the wings changed with color.

On one flight it had a white constant blinking. This flight was during the day. The blinking was slow and repeated up to thrice.

On the second flight, there was a blinking green light along with the blinking white light. This blinking was fast so I couldn't get a clearer shot and this is during sunset.

Note:-In the above two images both are of the Airbus A320 Sharklet. I believe it has something to do with tracking and relaying the coordinates to the ATC.


texts: Manufacturers are narrowing seats. Any possibilities for price cut?

texts:
To squeeze more profits from each plane, the airline industry in the
  last few years has begun to install extra rows of seats,  leading to a
  crunch in legroom that has sparked tiffs and feuds among frustrated
  passengers. (Source)

.

  Airbus has suggested 3-5-3 configuration for A380, making airlines
  have many extra seats.Source

A similar plan is there for the B777. Is it likely that airlines will pass on some of greater earnings to their passengers, in return of the lack of comfort?


texts: Is there an analytical description of the NACA 642-015A profile?

texts:
While searching for symmetric profiles I stumbled across different definitions (point-clouds) of the NACA 642-015A profile.

http://airfoiltools.com/airfoil/seligdatfile?airfoil=n64015a-il
http://www.airfoildb.com/airfoils/418.dat

The figure below (skewed) shows the difference in percent chord on the secondary axis (green markers).

What causes these differences and is there a analytical description I could use to create a point-cloud with higher resolution.

Another question is:
The NACA Reports I could find via Google all feature the NACA 642-015 (without the "A"). The difference between NACA 642-015A and NACA 642-015 is an increased thickness of the A-version towards the trailing edge.
Who introduced or developed the A-version?


texts: What short-term alternatives do airlines have to replace their grounded Boeing MAX 8s?

texts: The MAX 8 fleet is grounded: what are the other practical aircraft platform options available to AA, SWA or Continental that ensures that ticketed summer 2019 passengers arrive at their destinations safely?


texts: Why is there a plateau in helicopter H/V diagrams?

texts:
The "dead-man's curve" in a typical helicopter height/velocity (H/V) diagram is commonly referenced to indicate that "towering flight" is dangerous and avoided in general practice.  (Simon explained, "The Avoid curve [outlines] the combinations of height and speed in which test pilots (i.e., the best) have demonstrated that a safe landing is possible if the engine quits.")

But H/V diagrams also have second envelope that is marked for avoidance.

I don't know if this area in the lower right has an ominous name: If not perhaps we should call it the "dead-man's plateau?"

But why is it considered unsafe to fly at extremely low altitudes at indicated airpseeds above about 50 knots?

In a comment on this in the answer above Simon says, "At that speed, if the engine quits, the nose will pitch down and you will be on the ground, with no control and high speed, before you know what's happened."

Can someone elaborate on the dynamics of this?  Why would the nose pitch down abruptly if the engine quits?  If that's such a reliable effect would it not be trivial and worthwhile to have a torque-driven spring that bears on the cyclic, so if torque suddenly changes then the cyclic is just as suddenly nudged backwards?

In any case, one is left wondering if the full answer isn't more nuanced: The most striking characteristic of the dead-man's plateau is that it appears to be the height at which one enters ground effect.  Is there some other aerodynamic phenomenon at play in high-speed ground effect flight?


texts: Is there an equation for jet engine efficiency as a function of turbine inlet temperature?

texts:
I know that there is a relation between the turbine inlet temperature and the engine's efficiency. But, can anyone provide an equation or efficiency as a function of just the turbine inlet temperature?

I am looking for something like this: If the turbine inlet temperature goes up by 200K, efficiency goes up by 10%. Any numbers like this are appreciated.

Also, let's say that if GE invents a material that does not melt at all(just imagine), what is the highest temperature that can be produced by burning the fuel assuming nothing can melt.


texts: What is this RAF biplane, and where was the photo taken (possibly in the 1920s)?

texts: My grandfather is in the middle row. He joined the RAF as a boy entrant in 1920. He served in Iraq 1924-27 and India 1927-29 so I suspect by the uniforms this is from one of those postings.


texts: What is the force exerted by the catapult on aircraft carriers?

texts:
On aircraft carriers there is a catapult that slingshots aircraft so that they can gain lift on the short carrier deck.

I have a few related questions - the first is what is the force exerted / required by the catapult to sufficiently accelerate the aircraft; and is it adjusted per aircraft type or a uniform value?

I imagine carrier takeoffs/landing cause additional stress on the aircraft; but does it have a dramatic effect on the lifetime of the aircraft vs. their non-carrier configured twins? Or is it compensated for by a more frequent maintenance schedule?


texts: Can a closed Airworthines directive get reopened by a new revision?

texts: There is an Airworthiness Directive that has been closed by accomplishing its terminating action. But there's a new revision that changes the terminating action. Do I have to comply with the new terminating action to close the AD?


texts: What are these light like panels on the overhead bins of Boeing 737?

texts: These light like panels are seen in older Boeing 737s. I've never seen them turn on. Could someone enlighten (no pun intended).


texts: How is collision avoidance regulated in controlled airspace in Canada?

texts:
According to CAR 302.31(3) "Compliance with Air Traffic Control Instructions and Clearances"

  The pilot-in-command of an aircraft may deviate from an air traffic control clearance or an air traffic control instruction to the extent necessary to carry out a collision avoidance manoeuvre, if the manoeuvre is carried out

    (a) in accordance with a resolution advisory generated by an ACAS; or

    (b) in response to an alert from a TAWS or a Ground Proximity Warning System (GPWS).

I know that even in controlled airspace with separation/conflict resolution, and without equipment mentioned in (a) and (b) it is the responsibility of the pilot to avoid collisions. Is that covered by a different CAR?


texts:
I'm currently working on modelling a Super Etendard and just have a few questions on what are some small parts.

First of all, any ideas what this tube thing is on the right side of the exhaust? My best guess is a fuel dump nozzle but seems like a bit of an odd place?

Next, any ideas what this tube thing is, seems to have a hole in it so maybe some kinda sensor intake or something?

Will most likely have more questions as time goes on but would be good to know what are these things?

EDIT: Also any idea what these bits might be under the wings?


texts: My father was Prog mgr of F14. Where can I sell or donate his memorabilia or where is site to help?


texts: Why and how do atmospheric properties sometimes vary from the ISA?

texts: I'm curious as to why sometimes atmospheric properties don't match the ISA's. One reason I am considering is due to calibration discrepancies. By atmospheric properties I mean temperature, Density, Pressure etc.


texts: When rearranging the lift force equation to solve for lift coefficient instead of lift force, why is the numerator often given as F not 2F?

texts:
the standard description of the Lift force affecting the lift surface is:

$$
F={\dfrac{1}{2}}\rho v^{2} SC_{L}
$$
the basic rearrangement gives the following definition of the lift coefficient:
$$
C_{L}={\dfrac{2F}{\rho v^{2}S}}
$$

why is the above expression met so rarely? with the standard skipping the 2 multiplier?
$$
C_{L}={\dfrac{F}{\rho v^{2}S}}
$$

I've checked 30 scientific papers, those measuring the lift\drag coefficients.

28 papers have had F
2 papers have had 2F


texts: How ribs angle change wing overall shape?


texts: Can/do commercial flights change their flight path during flight?

texts:
Looking at the paths of the same flight on two different days, I noticed they flew very different paths.

Short Path:1

YAY N184B TOPPS ENE PARCH1

Long Path:1

NIBAX G462 TUMAK UL602 ORSOL UL602 DAVUS UL602 TASMI UL602 ITBIT UM860 KABAN UT334
INB UL852 UDROS L621 REVDA UP193 CND UP193 KARIL UL624 LABUK UY444 ELMEK UL726 OKG
UL984 NOSPA TOLVU UN857 GIMER UT300 EVX UT176 LGL UN491 KOKOS UN585 REGHI UN480
ETIKI NATD DOVEY LACKS BERGH L454 OWENZ CAMRN CAMRN4

I asked a similar question in the past. This is what I want to know:

What are the reasons which can cause a commercial flight to change its path mid-route?
How it is planed and executed?
I am sure the captain is the final authority on this, but who else is informed?

1Route Source: FlightAware.

P.S.: I could not understand the routes at all.


texts: What safety rule replaced the now-rescinded two-person rule (after Germanwings 9525)?

texts:
In the aftermath of Germanwings 9525 in 2015 many airlines instituted a two-person rule for the cockpit (aka "two-man rule") - with a flight-attendant replacing whichever pilot left the flight-deck.

In 2017 the industry rescinded that rule. Articles about the repeal of the rules don't mention what alternative processes are being used to prevent another occurrence of sole pilot murder-suicide - or a hypothetical where both pilots have suicidal intent - or when a single pilot is incapacitated while the other pilot is out of the cockpit for medical reasons or other reasons?

The problem being that while the reinforced cockpit door can be opened with an access-code, the occupant of the cockpit can countermand (indefinitely?) the access attempt. Has that policy been changed?

What safety-rule or practices are being instituted to protect against this - or is the pilot murder-suicide scenario being removed from the threat-model entirely? (so if I see one of the pilots banging on the cockpit door while in flight I should resign myself to my fate?)


texts: How do young pilots in the USA accumulate 1500-hours to become a first officer?

texts:
The FAA requires 1500 hours as a pilot:

  The rule requires first officers — also known as co-pilots — to hold an Airline Transport Pilot (ATP) certificate, requiring 1,500 hours total time as a pilot.

I am just interested in how can you get 1500 hours? This number is super huge unless you fly a trans-continental airliner. But you cannot fly an airliner without 1500 hours. Even having a private airplane, 1500 hours I assume will cost a lot - probably more than €500,000 in Europe. What is so specific about the USA? I fly gliders and a tug plane. I fly every weekend without exception and even sometimes after work. But I won't reach even 100 hours during the season. So to reach 1500 hours will take 20+ years. What about if you fly aerobatics...? Well of course there are some people who have these numbers but they are in their fifties and have spent all their lives in aviation! They don't even think about starting afresh in a first officer's career. So I am just curious how do young people log 1500 hours in the USA?


texts: Radio communications lost on climb out in IMC: when can I turn on course?

texts:
Let's assume:

I have been cleared direct from Knoxville Downtown (KDKX) to London-Corbin (KLOZ) at 6000ft. The direct heading is 357°.
I lose comms after take off from runway 26, I squawk 7600 and I'm in IMC
Assume I cannot land where I took off

My plan is to climb to 6000 as filed but I can't turn northbound on course because of obstacles. When can I turn on course? Is the proper procedure to fly the back side of the localizer westbound till I reach 6000 and then turn?


texts: Please tell me which trainer aircraft is this?

texts:
This trainer aircraft was spotted by me on a video on youtube, which said they were at the Lahore Flying Club. I really could not tell what aircraft they were on. If anyone can tell me, that would be great. Its some Cessna but which?

link to the youtube video:

Picture from the video attached.


texts: Why would a pilot pick this military airport as an emergency landing airport?

texts:
Looking at this old question, a comment suggested that Skyway Airlines flight 1267 was a possible answer to that question. Out of curiosity, I looked at the NTSB link of the Nov. 1996 incident report and was very surprised to find that this flight was on its way from Milwaukee, WI (KMKE) to Indianapolis, IN (KIND) (a 206 mile flight) but diverted to Fort Campbell, KY (KHOP) which is 191 miles south-southwest of KIND.

On its way from the KIND area to KHOP, the flight missed Cincinnati KCVG (85 miles from KIND) and Louisville KSDF (96 miles from KIND) as well as numerous other smaller airports that should have been able to accommodate a Beech 1900D.

I could understand this choice of destinations if KHOP were a civilian airport that happened to be a hub/maintenance facility for Skyway Airlines, but it's a military base.

Why would a pilot go so far out of his way to land at a military airport when there were numerous other suitable airports that were significantly closer, including, presumably, KIND itself, since the flight had to pass by there to reach KHOP?


texts:
What is UAV development platform? For example, STM UAV, Intel, Parrot and so on. I searched on Google, but couldn't get its exact meaning.
Thank you very much.


texts: What is the temperature range of engine mounts connected to the pylon?

texts: I want to know what is the temperature of the engine mounts in modern turbofan engines for example, Rolls Royce Trent 900. Also, what are the temperature considerations you need to make while designing a pylon?


texts: The F/A-18 Hornet and MiG-29 ailerons from the external parts of the wings go up some degrees in flight. Why?

texts:
In some parts of the flying envelope of the F/A-18 Hornet and MiG-29  the ailerons from the external parts of the wings go up in sync. They're made to go one up one down in order to get rolls, not up/up .

https://m.facebook.com/story.php?story_fbid=548605942390983&id=148530445855064


texts: How can a hang glider take off from flat ground?

texts:
There are a number of different ways of taking off with a powerless hang glider, the most commonly used being either running down a hill or jumping off a cliff/platform. This is how I learned to hang glide and is the standard way of getting airborne for most hang gliders.

However, I recently moved to Houston, Texas which is extremely flat. As far as I can tell, there isn't a single hill tall enough to take off from within a 100 mile radius of where I live.

How can I safely get airborne when I am on flat ground?


texts: Is there a height limit to national airspace?

texts:
Given the following facts:

satellites can operate at an altitude of 200km without triggering frontier violation incident
aircraft can trigger diplomatic protestations if they cross a frontier at an altitude of few kilometers
there is a gap between high altitude and space

There must be a altitude or height limit between national and international airspace. If so, what is this limit?


texts: Is using a DERATE for Takeoff actually reducing the power of the engine?

texts:
When one chooses a DERATE for takeoff (TO-1 or TO-2 in the case of a B737), does the system actually reduce the available thrust of the engines, or is it computing a N1 that corresponds to the reduced (de-rated) thrust?
Referring to a B737NG for example, does a setting of "TO 89%" produce the same thrust as a TO-1 or TO-2 with the same N1 of 89%?


texts: Is the time spent flying in a Sailplane concidered a valid flight hour for a LAPL / PPL license?

texts:
I live in the Netherlands.

In order to get a Light aircraft pilot licence (LAPL) license 30 flight hours are demanded, A private pilot licence (PPL) requires to have 45 flight hours.

flying in a Sailplane is lower-priced then a motorized airplane in my country.

So I'm wondering if flying in a Sailplane is concidered a valid flight hour for a LAPL / PPL license.


texts: In what circumstances could a 787 stay powered on continuously for 248 days?

texts:
The FAA has issued an airworthiness directive for the 787:

  SUMMARY: We are adopting a new airworthiness directive (AD) for all
  The Boeing Company Model 787 airplanes. This AD requires a repetitive
  maintenance task for electrical power deactivation on Model 787
  airplanes. This AD was prompted by the determination that a Model 787
  airplane that has been powered continuously for 248 days can lose all
  alternating current (AC) electrical power due to the generator control
  units (GCUs) simultaneously going into failsafe mode. This condition
  is caused by a software counter internal to the GCUs that will
  overflow after 248 days of continuous power. We are issuing this AD to
  prevent loss of all AC electrical power, which could result in loss of
  control of the airplane.

I'm curious: Are there any circumstances under which a 787 would remain powered continuously for 248 days?

[Edited to add a follow-on question:]

Boeing has said "If there is a definitive record of a powercycle within the last 120 days, no operator action is immediately required."  Does that happen? 120 days?

What is the longest period a passenger aircraft might conceivably be continuously powered on?


texts: What is the difference between planned true airspeed and actual true airspeed?

texts: My electronic E6B does calculations for both planned and actual true airspeed (yielding different results). I was told the difference has to do with assumptions about temperature, but the manual doesn't give any details. What is the difference between the two?


texts: I saw this contraption on the southeast corner of Eastern West Virginia Regional Airport, Martinsburg, WV (MRB). My first thought was this was some kind of NDB antenna but not sure.


texts: How can I keep my A&P license active without being in aviation?

texts: I am no longer in aviation. I do not want my A&P license to go dormant. Are there any ways to keep my A&P license active without being in aviation for over two years?


texts: Why would my transponder interfere with my ADF?

texts:
The ADF in my plane works very well until I switch the transponder to ALT. At that moment, the ADF needle is stuck in a random position and will not show the direction to the selected NDB anymore (the transponder works flawlessly).

Where is the interference coming from? Is it because the two boxes sit on top of each other on the dashboard? Or is it due to a bad placement of their respective antennas on the fuselage? Would seem strange to me, as their respective frequencies are far apart (kHz vs. MHz).

Any norm / guidance on how to install these two systems so that they do not interfere with each other?


texts: Which cruise altitude is prefered in engine-out operations of Boeing airplanes?

texts: On Engine Out Operation in Boeing Airplanes, which altitude is preferable, the OPT Altitude, the MAX Altitude or the RECOM Altitude of the ENG OUT CRZ Page?


texts: What geographical area does a METAR cover?

texts:
According to the FAA's AC 00-45G section 3.1, a METAR is defined:

  Aviation Routine Weather Report (METAR) is the primary observation code used in the U. S. to
  satisfy World Meteorological Organization (WMO) and International Civil Aviation Organization
  (ICAO) requirements for reporting surface meteorological data. A METAR report includes the
  airport identifier, time of observation, wind, visibility, runway visual range, present weather
  phenomena, sky conditions, temperature, dew point, and altimeter setting. Excluding the airport
  identifier and the time of observation, this information is collectively referred to as “the body of the
  report.” As an addition, coded and/or plain language information elaborating on data in “the body
  of the report” may be appended to the end of the METAR in a section coded as

  “Remarks.” The contents of the “Remarks” section vary with the type of reporting station. The
  METAR may be abridged at some designated stations only including a few of the mentioned
  elements.

What doesn't appear to be defined is exactly what area the METAR covers. It's understood that a METAR is a reporting for a particular station's current conditions at a particular time, but is there a more discrete definition for where the METAR's conditions can be expected?

The definition of a TAF specifically states that the forecast conditions are expected in an area around the reporting station with a radius of 5 statute miles. The METAR has no such specification that I can find.


texts: Are there some minimum criteria for a field to be registered with the FAA as an airstrip?

texts:
I spend an unacceptable amount of time 'flying' around the country (U.S.) via Google Earth and I'm always zooming in on airplane symbols to have a look at airfields.  In the western U.S. there are lots of rural strips that have the little aircraft symbol on them which I'm presuming come from the FAA.  Some of these fields appear marginal at best as legitimate airfields, especially the ones that are obviously part of a farm or ranch.

My question is what level of improvement is necessary for a field to be listed by the FAA as an airstrip?  Is there some minimum length, width, slope, etc.?  Is there some inspection that is done before you can get put on the charts and are there any ongoing checks to make sure the field is still there when the charts are updated?  Does the owner of a strip assume some ongoing obligation as a result of their strip showing up on a sectional?


texts: which country’s requirements for higher license?

texts: If I have a license registered in country A and want to add a higher license with a flight school in country B (both countries are in EASA), which country’s rules apply for requirements for the higher license? Let’s say, country A requires 10 more hours of something for the higher license, does that also apply if the higher license is done in country B?


texts: Why does a turbulent boundary layer cause more friction drag than a laminar boundary layer?

texts:
From what I understand, friction is caused by viscosity and a bigger Reynolds number signifies lower viscosity.

Thus, a higher Reynolds number(i.e. turbulent flow) results in lower friction.

But, turbulent boundary layer is said to have a much steeper speed gradient at the aircraft skin, causing much more friction drag.

These two statements seem contradictory. What am I missing here?


texts: Can a commercial airplane overtake another airplane going in the same direction?

texts:
If there are two commercial airplane flying towards the same destination, on the same flight path, and the second plane is being faster than the first plane, is the second plane allowed to overtake the first airplane?

If so, how close are two planes allowed to fly while overtaking each other?


texts: How does a jet fighter landing flare compare to a civilian plane?

texts:
How does a jet fighter flare compare to a civilian plane?

How low before flaring?
Do pilot keep track of pitch or AoA to know how much should be flared?
Is flare at last moment like in airliners, so after crossing runway threshold?
Will touchdown happen during the flare, or must the pilot bring the aircraft out of the flare to land more flat?

It's just 1 question. The bullet-points are just there to illustrate things in the answer I would like clarification of (which are all flare related).


texts: Why is magnesium not used more often as a structural metal in aircraft?

texts: Magnesium is lighter than aluminum for the same strength.  If the answer is corrosion, how much work has been done to improve the corrosion resistance of magnesium?  How much lighter would a magnesium structure be than an equivalent aluminum structure?


texts: When do you contact ATC when departing from a non-towered airport into class C controlled airspace?

texts:
When you're departing from an airport within controlled airspace, when should you contact ATC?  This is when the airport you were departing from is non-towered.

Scenario: I am departing a non-towered airport in class Charlie airspace. I need to request VFR flight following to another airport. When do I contact ATC?


texts: Why is the flight director at 9 degrees nose high when hitting TOGA?

texts: Why is the flight director set to 9 degrees pitch up, when pressing the takeoff / go-around (TOGA) button? In all the jets I fly, this is the case and I would be curious to know if other jets set their pitch attitude to a different value.


texts: Well as usually when you fly in an airplane they Determine the luggage weight but how do they calculate the airplane weight "necessary so the plane doesn't get overweight" when they don't know the passengers weight and how do they deal with obesity (after my respect to all differences between people)


texts: Can autothrottle be used without autopilot (and vice versa)?

texts:
In commercial passenger aircraft:

Can autothrust be used with A/P disabled ?
And can A/P be used without using autothrust?

Citable references very welcome!
If the question depends on a specific aircraft type, then please B777.


texts: What exactly are the "sealed" leading-edge slats in B737 short field performance aircraft?

texts:
"The 737 design enhancements allow operators to fly increased payload in and out of airports with runways less than 5,000 feet long. The design enhancements include a two-position tail skid that enables reduced approach speeds, sealed leading-edge slats that provide increased lift during takeoff, and increased flight spoiler deflection on the ground that improves takeoff and landing performance"

Source: https://boeing.mediaroom.com/2006-07-31-Boeing-Delivers-First-737-with-Enhanced-Short-Runway-Package-to-GOL

What are the sealed leading-edge slats in B737 short field performance, and how are they different from the normal leading slats in typical B737?


texts: How does the V22 Osprey manage such high rotor speeds without shock waves?

texts:
I read somewhere that the engineers presented an ingenious solution to the rotor tip shockwave problem, except the article didn't actually explicitly mention it.

So, does anybody actually know if such a solution even exists ? And if yes, what is it ?


texts: Why is a part from a Boeing 777 being analysed by Airbus?

texts:
Since MH370 was a Boeing 777, why are they taking the suspected wing flaperon to Toulouse, France?

Are some spare parts made by Airbus?


texts:
I was looking at the RNAV (RNP) 6 approach into Gunnison (KGUC) and noticed something quite strange:

If the image isn't clear enough -- the approach is Not Authorized for approach category A aircraft (which of course includes every last helicopter on the planet).  WHY would this be so?  Is there some operational or technical reason a slow-moving category A aircraft or helicopter can't fly this approach, even though their avionics might be perfectly capable of doing so? Or is this some sort of charting error I should bug the FAA about?


texts: Brace position - Why hands atop head in the UK, but on ankles or atop seat in front in the US?

texts:
Source: Does the brace position save lives?,  By Oliver Smith, 2013 Mar 13, telegraph.co.uk

"To adopt the brace position passengers should place their feet and knees together with their feet firmly on the floor,” added [Steve Allright, a British Airways training captain] .... “Feet should be flat or on the balls of their feet, and further back than the knees. In the event of an impact, this position helps prevent shins and legs being broken against the base of the seat in front, which would obviously hinder evacuation.
"Passengers should bend as far forward as possible, if it's in reach, they should rest their head against the seat in front, with hands placed on the back of their head. Hands should be placed on top of one another (not with fingers interlocked) [emphasis mine; this seems a critical fact], elbows should be tucked in to their sides. The head should be as far below the top of the seats as possible. This position prevents flailing of the arms, minimises the risk of broken fingers and protects the head from moving objects.”
The position varies slightly in the US. Rather than placing hands on the back of the head, passengers are advised to place them on top of the seat in front, or to hold their ankles.

1. Why the difference in the hands' position? Which is more protective?
2. What does it mean to 'hold their ankles' with the hands? Simply place your hands atop your ankles?


texts: Special Purpose Tablet for Commercial Navigation app

texts:
I just posted a request for advice on how to find right android tablet to integrate commercial flight navigation app (e.g., iFLY) to avoid bloat, OS updates that may not be compatible, and add future WiFi integration with commercial ADS B-In data overlays (e.g., FlightBox, etc.) on the Geo-referenced moving map in the navigation app.

(Please help, I don't know how to send this request to Don Hulme.)


texts: Is "margin final" an ATC instruction in USA?

texts:
I was south-east of the airport and the active runway was 24. The ATC said, "Make straight in and remain south." And then he said, "Margin final, cleared [to] land."

What is margin final? I'm an international student so I may have misheard. I thought it's for joining final so I said, "Join final, cleared to land." The controller did not say anything after.

If it wasn't "margin final," what could it have been?


texts: Can anyone identify this 1910s era biplane?

texts:
I tried a number of searches with absolutely no luck. I remember a few that looked sort of similar without that smooth aerodynamic nose and body. I did try at least.

If this helps, the individual standing before the plane is believed to be of French origin or descent.


texts: Is it possible to fly a Straight and Level flight at high speed?

texts:
The question arise while discussing with some of my student pilot friends that as we have been performing Slow Flight we have to keep increasing the AOA of the aircraft to compensate for every lose in airspeed. What about "FAST Flight", decreasing the AOA of an aircraft for every gain in airspeed. Maybe Negative AOA.
I'm aware that lift could be generated with negative AOA from the graph of AOA vs CL. And if you could explain to me why there is a specified cruise setting?


texts:
What should I wash my airplane off with?  As a new aircraft owner, any help would be appreciated.

I am pretty sure using dish washing detergent is not the best here as we are told not to use the stuff on our cars.


texts: How does an airplane owner correct an airplane misidentification showing up on FlightAware?

texts: I have a friend in Pennsylvania with a plane in Pennsylvania. FlightAware is currently showing his airplane in the Bahamas, when it is not. He wants to know whom to contact to get this corrected. I'm assuming it's in some database being use by both FlightAware and FlightRadar24.


texts: Can a gas turbine be able to switch from torque to thrust?

texts:
Can a turbine engine be switched from providing torque (like a helicopter) to the rotor to transfer power to provide exhaust thrust (like a jet plane)?

Related: BV-347 upgrade this way?


texts: What is the distance unit on a navigation display?

texts:
I want to learn what is the distance unit on a navigation display.

I pointed the distance marks with red circles on the navigation display. What are these 10, 15 etc. values' unit? Are they representing mile, nautical mile or kilometer?

And can it be adjusted in a different measurement unit (mile, kilometer or nautical mile) or is it a standard unit for aviation and navigation displays?


texts: Application of Bernoulli Energy Conservation

texts:
In what cases does the static pressure decrease when the velocity increases in a flow.

And in what cases does the static pressure remain constant whilst the velocity and stagnation pressure increases?

Please answer with respect to Bernoulli's equation: Po1 = Ps1 + 0.5*rho*v1^2

For example in a closed circuit wind tunnel to what extent does the fan convert static pressure to dynamic pressure and to what extent does it just add energy by increasing the dynamic pressure.


texts: Do GA pilots routinely request "flight following" from ATC, and why?

texts:
My understanding is that private pilots are able to contact air traffic control and request "flight following", as it may help them with their situational awareness. Beyond that, however, I'm curious:

Is this a common procedure? What sort of "situational awareness" benefits can be realized by a "flight following" request? What are other pros/cons of such a request?


texts: What factors should be considered when taking private pilot renter's insurance?

texts: I'm just about to start on my first solo and was informed by my CFI that I need to have renter's insurance at a cost of about $180/year.  I looked on AOPA for this insurance and confirmed that the prices is correct if I choose no coverage for "liability for damage to non-owned aircraft".  What are the factors I should consider in making the decision to add/not add this other level of coverage?


texts: What aircraft is this flying near Greenford?

texts:
I live in the suburbs of London in Greenford (near RAF Northolt Base) and today I heard a droning sounds which, albeit from my limited experience, sounded like a propeller plane. I checked my generic flight radar application on my smart phone, no result. I then checked the ADS-B tracking website which identifies most military aircraft that aren't flying covertly but, again, no result.

I did manage to take a picture of the aircraft and it looks like a small passenger turboprop plane - so any ideas about what aircraft this is and why it wouldn't be showing up on any radars? It does not seem like a stealthy fighter jet by any means.


texts: What does ® mean in the Chart Supplement (A/FD)?

texts: What does the circled r: ® mean in the Chart Supplement (A/FD)? You can see it here to the left of SOCAL APP/DEP CON:


texts: The pendulous vane uses precession to correct a gyro by small jet air, but I   do not know how it works. As far as I study, when gyro is tiled, one of the doors open and the other one is closed. This principle seems to be hard for me to understand. Could you let me know the principle of pendulous vane, and how it corrects a gyro's error?


texts: Which ATC instructions should be repeated back by the pilot?

texts:
AIM 4-4-7 (b) says:

  Pilots of airborne aircraft should read back those parts of ATC
  clearances and instructions containing altitude assignments, vectors,
  or runway assignments as a means of mutual verification.

As a student pilot soloing into class C airspace, on one flight ATC kept repeating everything back until I spoke it back to him. As I approached the airport he informed me of the bearing (12 o'clock) and distance to the airport until I acknowledged him (comms were pretty busy so I didn't initially repeat back his information).

Since then I've noticed that if I don't repeat back wake turbulence warnings verbatim they will repeat the warning until I do. With a traffic alert I repeat back immediately 'looking for traffic' because if I look first they'll keep repeating the warning.

Aside from AIM 4-4-7 is there any more specific guidance?


texts: Is the highly optimized high subsonic cruise airfoil less safe for higher AOA flight?

texts:
An examination of the 737 airliner wing profile and that of a blue whale leads to the question of whether the high Reynolds number subsonic cruising airfoil and the low speed, high AOA airfoil are compatible.

Supercritical airfoils are designed for efficient cruising flight, relying on bottom lift and minimizing acceleration of air over the top to avoid creating drag producing transsonic shock waves.

The blue whale is designed to cruise efficiently over thousands of miles, through a viscous, non-compressible fluid (water). Their shape includes a rounded, sloping lower fore and a flatter top, very similar to a supercritical airfoil!  Applying thrust to this shape would provide "lift" simply by directing water "down" (or pushing the whale "up").

Reynolds Number = Velocity×Chord/Kinematic Viscosity

Reynolds Number 20th century Type VII U Boat (submarine):  speed: 4 meters/second
                  chord length:  70 meters. Kinematic viscosity (sea water): 1.04 × 10e-6

      4 × 70/1.04 × 10e-6 = 269 million

Reynolds number Blue Whale:  speed: 5 meters/second, chord length: 30 meters
                       Kinematic viscosity (sea water):  1.04 × 10e-6

      5 × 30/1.04 × 10e-6  = 144 million

Reynolds number Supercritical Airfoil (approximate):  speed 300 meters/second,
Chord length:   4 meters    Kinematic Viscosity (air):    1.46 × 10e-5

    300 × 4/1.46 × 10e-5 =     82 million

Reynolds Number Cessna 172 Airfoil :  speed 30 meters/second
Chord length:  2 meters        Kinematic Viscosity (air): 1.46 × 10e-5

   30 × 2/1.46 × 10e-5 =         4 million

Reynolds Number Albatross (bird) airfoil: speed 10 meters/second
Chord length: 0.2 meters       Kinematic Viscosity (air): 1.46 × 10e-5

  10 x 0.2/1.46 x 10e-5 =        140,000

We can see the supercritical wing is more in the range of the blue whale!

When pitched up to a higher AOA, this shape would be a very poor wing in the classic Bernoulli sense, as the significantly contributing top lift would be lost at a lower AOA than a top rounded airfoil, behaving much more like a flat plate (see polars).

There are accounts of airline pilots extending their slats at higher speeds for better performance (and getting into trouble for doing so).

So, for modern designers, would it not be important to consider a more robust low speed system that could be left on (in varying degrees) at higher speeds (V maximum flaps and slats extended airspeed) to help avoid stalling?

This could create a wider safety margin for the climb-out and landing phases of flight. Hard earned efficiency gains in cruising flight (from the supercritical wing) would be kept, when they are fully retracted, but only at safe speed and AOA conditions (for example, above 10,000 feet or at cruising flight level).


texts: Why would all passengers be asked not to eat peanuts when there is one allergic person on board?

texts:
In this review of BA British Airways Club World London City flight there is one thing I don't understand:

  ... it was announced that a passenger onboard had a severe nut allergy, so they asked people not to consume nuts on the flight.

I've never seen this in a restaurant or any other setting. I gather it's usually the responsibility of the person suffering from allergy to avoid what they are allergic to (usually with a legally mandated help, like known allergens listed on the menu).

I understand that having a person have an allergic reaction to nuts (which can get very bad) itself is a risk to the whole flight. What I'm missing is how other people eating nuts may endanger the one person with allergy.

The only thing I can think of is perhaps some loose nuts flying into the allergic person's meal (or, more directly, mouth) in a severe turbulence. Is that it? Is it a normal procedure to ask passengers not to eat nuts when there is an allergic person on board?


texts: What are possible explanations for fuel being expelled in this video?

texts:
In another question, I asked about whether or not a fuel spill would be reportable or not. The answer was "no", because the aircraft was not in flight.

What are the possible causes of the spill demonstrated by this video?


texts: What are these five indicators at the front of the 737 passenger cabin?

texts:
As a passenger I noticed set of five indicators on ceiling at the front of the 737 passenger cabin. They are: red, yellow (or white), blue, white, red.

Red ones seem to be coupled together (what could indicate their higher importance and also prevents problem with failed light bulb).
On the photo, there seem to be two white indicators but on older models I almost certainly remember that one of them was yellow.

I have seen those indicators in old and new 737 models. I understand they inform the cabin crew of something but I did not find explanation so far.

What is the exact purpose of each indicator?
Are they controlled manually or automatically?
Are they Boeing-specific?
How are similar conditions communicated to cabin crew in other similar types of aircrafts (e.g. A320) which do not seem to have these indicators?


texts: What is the Optimum center of mass location for an air-craft?

texts:
I was doing my mathematics exploration, and i would like to know what is the optimum center of mass location of a plane.

Specifically, what would happen if the point were to be too close or too far away from the point where the lift force was acting from.
It would be helpful if you could cite a source for your information.

Thank you!


texts: Why would an ILS installation need a “reflecting surface” around the glideslope antenna?

texts:
According to the NTSB, the installation of a glideslope serving runway 11 at KHTS (Tri-State Airport, Huntington, West Virginia) was delayed for over twelve years by the lack of suitable terrain for the glideslope antenna, and, when the glideslope was finally installed (following a CFIT accident involving an aircraft making a nighttime approach to runway 11), these same terrain considerations forced the use of a nonstandard installation utilising an offset antenna (my emphasis):

An instrument landing system was scheduled for installation and commissioning at the Tri-State Airport in June 1958.  The localizer, middle marker, and outer marker installations were completed at that time, but there was insufficient terrain to provide adequate reflecting surface for the glide-slope antenna, within the existing criteria.  Three applications for runway extension, which would also provide suitable terrain for the glide-slope antenna, were submitted to the FAA in Fiscal Years 1967, 1970 and 1971.  The 1967 and 1970 requests were not approved because the necessary “matching funds” from the sponsoring agency were not available, and consequently the Federal funds were not committed.  The 1971 request was still under consideration at the time of the accident.
Subsequent to the accident, concurrent negotiations involving the FAA, West Virginia State Aeronautics Commission, Wilcox Electric Company, Inc., and the Tri-State Airport Authority, resulted in the installation of a nonstandard glide slope for Runway 11, paid for by Federal funds only.  Prior to installation, the FAA estimated that there was a 50 percent probability of success with the glide slope.  A Wilcox Mark I, Series 8020 transmitter was placed 1,211 feet south of the runway centerline and 960 feet west of the Runway 29 threshold.  The elevation of the site was 805.2 feet m.s.l. and the antenna was rotated 13.5° to align with the middle marker.  This offset was required to place the site on suitable terrain, and resulted in an unuseable signal below 1,075 feet m.s.l.  Consequently, there was no reduction in the minimum altitude authorized for the instrument approach.  However, the signal generating capability of the facility to date has been as reliable as standard systems.  [NTSB AAR72-11, page 12 (numbered as 9); the runway has since been extended, and now measures 7,017 feet (and is now runway 12/30, due to changes in the local magnetic declination over time).]

The requirement for “adequate reflecting surface” is surprising; intuitively, one would expect that UHF-radio-wave-reflecting surfaces near your glideslope antenna would be a bad thing, due to the potential for multipath interference from reflected glideslope signals.  Why is this not so?


texts: What FAA or other regulations apply to autonomous quadcopters?

texts:
I am a software engineer and hobby roboticist and I have just successfully built a quadcopter drone with a full-fledged microcontroller (running firmware that I wrote myself) inside of it, that flies around my backyard, identifies certain things that it finds and sends me reports of what it finds. I do not need to control it with any sort of remote at all.
What legal issues with the FAA and other aviation regulators might I face in trying to bring this to market as a consumer product? Never mind the electronics testing/certification/verification aspect (i.e. all the processes and hoops you have to jump through to have an official "UL" logo on your product). I'm wondering where modern US (likely FAA) drone law stands on completely autonomous, unmanned, non-remote-controlled quadcopter operations for commercial use -- not for delivering the mail like what Amazon is doing; this is just something that flies around on its own in your backyard or in a field, does simple object identification and knows how to steer clear of most obstacles.


texts: How to determine if an aircraft type is currently under investigation?

texts:
The Boeing 737 flew for several years despite rudder issues which had not been fully understood and resolved. It's conceivable that flyers who avoided the aircraft had had less probability of injury or death while flying.

How does one identify which aircraft are currently under some sort of investigation for similar, on-going issues?


texts: How much revenue do seat-back displays generate?

texts: Many airlines are toying with the idea of getting rid of seat-back displays, how much revenue did those seat-back displays bring in the form of in-flight advertisement? I would presume for a long haul flight the revenue might be more than what it is for a mid-range flight.


texts: When calculating the lift coefficient, what area is used?

texts:
Lets say I had this rectangular double curve wing. Orange represents the chord length, red represents the airfoil outline length below the chord line, green represents the airfoil outline length above the chord line, and blue represents the wing span.

If I were to calculate its coefficient of lift, I would need to know the area. Which area does it refer to? Could you explain how to calculate the desired area using this diagram?

Could it be the length of green multiplied by the length of blue? Could it be the length of green and red multiplied by the length of blue? Or something else?

Correct me if I am wrong, but in this case, I think the planform area would be the length of orange multiplied by the length of blue.


texts: What does "spark plugs appear yellow at the ignition point" mean?

texts:
I was reading the DLE-120 engine User Manual and saw this paragraph:

Caution: Running the engine with a lean fuel mixture will cause the engine to overheat and burn the electrode of the spark plugs. Pay close attention to the High-speed Needle adjustment. Running the engine with the proper fuel mixture will make the spark plugs appear yellow at the ignition point.

What does "yellow" mean in "Running the engine with the proper fuel mixture will make the spark plugs appear yellow at the ignition point"?
Does anybody have any experience or images of this phenomenon?


texts: Why is Boeing being blamed for the recent 737 Max crashes?

texts:
Boeing has received more than 5,000 orders for the aircraft, it has delivered 350 so far and only 2 of them have crashed. That's not a very high crash rate. The FAA, until just a day ago, was very confident that the aircraft is "fly worthy".

The Ethiopian crash investigators haven't even ascertained if the crash was due to a problem with the aircraft or if it was pilot error and already the whole world is assuming it was Boeing and has grounded flights worldwide. Why is this?

Why is Boeing being blamed for this? Flights crash all the time! Sure, not as much today as they did in the beginning, but they still do! We can't go on grounding every aircraft that crashed during flight! Plus the aircraft was in development for 5 years - I'm sure buyers were allowed to test the aircraft to their satisfaction before placing orders, Boeing themselves would've rigorously tested the aircraft, it was even approved by the FAA!

Shouldn't we make sure it was not the pilot's fault before we blame the manufacturer? Or did they already do that? I tried to find articles that explained WHY everyone is rallying against the company, but couldn't find anything concrete.


texts: Logging time towards commercial pilots license

texts: I am in a part 141 program trying to finish up my commercial pilots license. The airport we operate out of will be closed for a few weeks so I was wondering if I'd be able to rent a plane close to where I'm from to knock out some of the solo hours I have left. It wouldn't be a school plane and my instructor wouldn't be with me. Is this possible?


texts: Where can I find the NTSB order for Administrator v. Walkup and/or v. Hamre?

texts:
In a footnote to Administrator v Strobel, the NTSB states:

  Our precedent makes clear that, “[r]egardless of who is manipulating
  the controls of the aircraft during an instructional flight, or what
  degree of proficiency the student has attained, the flight
  instructor is always deemed to be the pilot-in-command.”
  Administrator v. Hamre, 3 NTSB 28, 31 (1977). This principle was
  reaffirmed in Administrator v. Walkup, 6 NTSB 36 (1988).

THE PILOT IN COMMAND AND THE FARS: THE BUCK STOPS HERE (ALMOST ALWAYS) has some other examples of determining who is PIC and also refers to Hamre.

I can’t find either one on the NTSB site or with a search. Does anyone have a copy or a link to Hamre or Walkup?


texts: Why do airliners park with the nose facing the terminal?

texts:
A few other questions have touched on why we don't board airliners from the front and back at the same time. My question is why is it that we choose to board at the front, rather than park the aircraft facing away from the terminal? This question shows that parking backward seems to be unusual. Why is this design not adopted widely?

I have two guesses:

Is it because of the jet blast? But this can be solved by towing the aircraft away from the terminal before using the jet engines.
Because it is difficult to attach the jet bridge without hitting the tail?


texts: What is the best combination of airfoil shape for flight in ground effect over water?

texts: What is the best airfoil shape for flight in ground effect over water?


texts: What is the specific FAA regulation with regards to a pilot dropping jumpers into a solid cloud base?

texts: What is the FAA regulation with regards to a pilot dropping jumpers into a solid cloud base?  I saw some parachute jumpers come through a solid cloud layer with a base at around 1300 AGL.  They landed maybe 1/2 mile from the airport on either side of a fairly busy four lane state road.  The cloud layer was solid 1600 AGL to 3000 AGL (we flew IFR and I recorded when we entered and when we got above the cloud blanket).  We were above this solid layer for 2 hours of our 3 hour flight.  Once home, I looked for the FAA regulation with regards to pilot's rules when dropping jumpers in such conditions but could not find any.  It is dangerous for the jumpers, the cars on the highway and for IFR pilots flying in the vicinity but but is it regulated by the FAA?


texts: What is an acceptable phugoid oscillation duration?

texts:
What is an acceptable settling time for the phugoid mode in a large aircraft?

As a more specific question, what is the settling time when the aircraft (say, a B747 or an A320) switches from Climb to Cruise phase at the top-of-climb?


texts: Is there any way to reduce the noise and vibration in a C-130 Hercules?

texts:
We are using C-130 B and E Models with T-56 A-15 engines and Hamilton Sundstrand 54H60-91/117 propellers. A lot of vibration and resonance are felt on these military version aircraft even after using solid state synchrophasing and conducting prop balancing.

I wanted to know if there is some system to make the aircraft quieter. Except for shutting down the engines of course :)

Are there any resonance controlling items to make the passengers more at ease?


texts: What is the ALT INTV on the 737's autopilot?

texts: So, I was watching a quick tutorial on the FMC on YouTube. The FMC somehow had a 5000 ft restriction, and the guy got clearance to go higher up, and he set his altitude on the AP panel, and he pressed the ALT INTV button.


texts: Do pilots have to stop at the hold position of the takeoff runway?

texts: Or in other words, is the takeoff clearance ever given (implicitly or explicitly) before the aircraft reaches the hold position, so that the pilot can keep rolling through the hold line and to the takeoff roll?


texts: Has anyone tested or flown permeable wings to increase efficiency?

texts:
See this article: Aerodynamic Performance Improvements Due to Porosity in Wings at Moderate Re
Was wing porosity ever tested/used for real aircraft?
source:

The aerodynamic efficiency parameter clearly shows the positive effect of the permeability for low angles of attack. Having a permeable section on the airfoil surface will provide better aerodynamic characteristics when the angle of attack is less than 10°. This is compatible and in agreement with the observation of other researchers on the effect of the holes on the aerodynamics characteristics of the airfoil that concluded that “at a transitional phase where Re= 40,000 and the angle of attack ranged from 0 to 9°, the L/D ratio was higher compared to the same wing without holes


texts: What is the true top speed of the SR-71?

texts:
By "true" top speed I mean the absolute fastest horizontal airspeed the aircraft can achieve if damage to the engines is disregarded (similar to how the MiG-25 apparently can reach mach 3.2 but may damage its engines beyond repair). Catastrophic structural failure (of anything beyond the engines) is not permissible in this scenario.

In "The Untouchables" Brian Shul claims that he reached mach 3.5 while evading a missile. This is also stated in the Wikipedia article on the SR-71 with a citation to the same book.

Are there any other sources than his own book that can confirm or reject this claim? Can it be argued for or against this top speed claim on technical merit or physical limitations?

On Wikipedia it is also stated "Maximum flight speed was limited by the temperature of the air entering the engine compressor, which was not certified for temperatures above 800 °F (430 °C).[57]"

However, it is not clear how much abuse beyond this the compressor could take. It is possible to give some estimate or educated guess based on the materials used?


texts: What improvement was made in Su-35 over Su-30?


texts: What is the function of the tail section on a fixed-wing aircraft?

texts: In a generic fixed-wing aircraft like a Cessna, what is the function of the tail section, i.e. the rudder and elevators?


texts: Difference between FMCF and AIMS on B777?

texts: What is the Difference between Flight Management Computing Function and Airplane Information Management System on B777?


texts: What is the cargo capacity of a Boeing 737-200/-300?

texts: I would like to know the maximum commercial load of a cargo aircraft B737-200 & 300.


texts: How did planes measure their speed relative to the ground before GPS?

texts:
How did planes measure their ground speed before GPS?

If they used some sort of anemometer to measure speed, that would only measure the speed of the plane relative to the air through which it is passing.

Therefore, I'm wondering how speed relative to the ground was measured before GPS.

I'd be very grateful if someone could explain this to me!


texts: Are there any limitations of diopters (corrected eyesight) in the US?

texts:
According to FAA standards, there seems to be no diopters limitation for a first class medical.
I'm Japanese. JP CAC limits it. UK CAA also does.
I would appreciate it if you could tell me whether my understanding is mistaken or not.


texts: Why were the windows on the Concorde about the size of a hand?

texts: I just saw a comparison between the 787 and Concorde windows. I could be wrong but it almost seems like a hand could cover the majority of the window.


texts: Is it safe to use a parallel runway's PAPI/VASI?

texts: Many airports have parallel runways but only one runway has a PAPI/VASI. If both runways start at the same point and have similar touch-down points, is it safe to use the parallel runway's lights for the approach and landing?


texts: Who manufactures the landing gear on the Airbus A350 series aircraft?

texts: Where are they made? I assume that they are made out of titanium. Right?


texts: At what minimum occupancy ratio can airlines operate profitably?

texts:
Often, airlines are unable to sell all the seats of a flight and some seats go unsold. So, with what occupancy ratio is it usually profitable for an airline to operate?

For example, Recently, a Turkish Airlines A330, flying from Bangkok to Istanbul (12,000 KM) made an emergency landing after a bomb hoax. The interesting thing was that it was carrying only 142 passengers, against its marked capacity of 250 passengers (occupancy ratio of about 0.6).

And what are the factors which would influence this choice – like probably, it would be cheaper to operate a B787 with 0.6 occupancy ratio compared to a B747.
What are some other factors which influence this?


texts: What special handling characteristics or techniques do biplanes have?

texts:
How does flying a biplane differ from flying a monoplane? Apart from the increased drag and lift, how does it handle differently, and what effect does that have on manoeuvring?

In particular, I'm interested in differences between a biplane and a hypothetical equivalent monoplane, not differences between vintage airplanes and modern ones, or differences between aerobatic and utility airplanes.


texts: Why does the Grumman Bat feature inverted winglets?

texts:
I've been fiddling around with trying to make a blended wing body aircraft. While modelling, I heard from someone that the design reminded them of the Swift Killer Bee (now Grumman Bat). One distinct feature that I noticed from the design of the Bat is their use of an inverted winglet. Does anyone know why the design features an inverted winglet rather than a conventional one? The more recent designs of the UAV also features a conventional winglet in addition to the inverted one. Are there any benefits for this design?

I would also like to know if anyone has an idea on how the UAV handles landing? Is the inverted winglet capable of supporting the stresses experienced during landing? I can only find that the Bat comes with an optional landing gear while normally it is supposed to be caught by a net.


texts: What are these green "bags" on the SSJ100?

texts: I've seen some green "bags" on the SSJ100 when they were building it. What is the purpose of these?


texts: What are the pros and cons of wingtip tanks?

texts:
I am looking into the aerodynamic pros and cons of wingtip tanks. Let's assume they're perfectly streamlined, optimally placed and sized for a given airframe.

I am aware of the purpose of fuel storage on a wing that's too thin or otherwise inadequate for 'wet wing' fuel storage and as a means of permanent fuel storage, but how do tip tanks interact with airflow on the end of the wing?

What are the pros? Are tip tanks effective as 'winglets' or drag-reducing tips, controlling spill and cleaning up vortices? Do they contribute to useful lift and if so what percentage and what is the overall effect on the wing?

And what are the cons, aerodynamic, structural and general? Do they require heavy modifications to the spar or wing in general to attach?

Overall, if a wing design can include bladder or wet wing storage, would it be better not to employ tip tanks?


texts: If an A320 loses an engine why does the landing category go to CAT3 single?

texts: Following an A320 engine failure, why does the the landing category go to CAT3 single even if the APU has been started and is powering the AC bus that was lost by the failed engine?


texts: How to make a cockpit LCD display night vision compliant?

texts:
I am trying to understand what does it means by making an LCD display compatible with Night Vision? The aircraft is an old Mirage of 1950's.
If I use an LCD display in it's cockpit display unit then how would I make the LCD compatible with Night Vision capability?

Do I need to select a specific color (wavelength or frequency on spectrum) to display the data on the screen?
Or do I need to put some filter sheet on top of the LCD screen to make its Night Vision compatible?
Or does it mean something other than these?

Edit:
The only info about the OEM display is follows:
"The display is an ac TFEL flat panel display combined with contrast enhancement bandpass filters to achieve both sunlight-readability and night-vision google compatibility"
I want to replace this TFEL display with an LCD display. But I dont understand how will I do night-vision google compatibility in an LCD?


texts: Why is there a cutout in the pilot seat (looking as if it had separate "legs")?

texts:
Why is there a gap in the seat (between the legs)?
What function does it have?


texts: What is the helicopter in the background of this image of the V-22 Osprey?

texts: I found a photo of a V-22 Osprey alongside an unknown helicopter on the left corner:


texts: Can a laser Doppler anemometer be used to measure airspeed?

texts: Could this be used in place of or in addition to a pitot-static system?


texts: Could a light helicopter pilot land a transport-category helicopter?

texts:
Related question, but not a dupe as that's about starch-wings and the gap between light fixed-wing planes and fixed-wing transports does seem larger than the similar gap in rotorcraft...

Let's say our good friend Simon, with his considerable amount of cyclic-time in small-to-modest helicopters, is onboard an S-76 (or other similar large helo) and both the pilots find out that the fish was a bad choice of preflight meal.  How much assistance would he need from someone on the ground with time-in-type in order to get the helicopter on the ground safely, assuming this was in VMC?


texts: How reliable is the Airbus FAC calculated gross-weight?

texts:
I've noticed some variation between loadsheet weights and FAC (Flight Augmentation Computer) calculated weight. That's of course normal, since loadsheet is calculated with standard weights and FAC calculates the weight from alpha and speed (at least as far as I know).

Question: Does anyone have any information about the correctness and reliability of the FAC calculated gross-weight?

I'm also interested in how exactly, and with what parameters, the FAC calculates it.


texts: Is the Airbus Beluga's safety record comparable with the record of other Airbuses?

texts: Upon first sight, to the uneducated eye, the Airbus Beluga looks incredibly 'un-aerodynamic'. Is the Beluga just as safe as other Airbus models?


texts: What plane can land the slowest on the water? What plane can land on the choppiest water? Is there a way to land between the waves?


texts: What is this very distinct humming noise coming from the IAE-V2500 engines of the A320 during taxi?

texts:
So I am a huge fan of the A320, and in a less broader sense, the A320 with IAE-V2500 engines. Arguably the greatest engines in the industry with the greatest sound. However though, I've had a question that I just can't seem to have answered so I'll ask here. If you're sitting inside an A320 with IAE-V2500's and you're taxing out to the runway, you here a very distinct humming noise coming from the engines. What I find confusing about this noise is that it sounds very different on the outside as I have spotted the A320 with V2500's in person, and the idle/taxi sound outside of the aircraft sounds very different from the inside. You can find the sound I'm talking about at timeframe 7:42 until takeoff (taxi) in this provided YouTube video:

Thank you all so much! -Niko


texts: A330 flown by low cost airline - is 8 cabin crew really all they have?

texts:
I'm reading the Australian Transport Safety Bureau report on an incident involving an AirAsia X A330 (PDF). The flight in question was intended to be Sydney to Kuala Lumpur so something like a ten to twelve hour flight.

The report mentions that there were 8 cabin crew on board.

Wikipedia says AirAsia has 377 seats in their A330's. Can it be true that they service that many seats with only 8 cabin crew ?


texts: Can you become a commercial airline pilot in Europe while being monocular

texts:
I’m not sure if I could get a EASA medical class 1 while being monocular. But I think that you can get a soda in the us and I want to know, if I could take a FAA medical class 1 and then fly in Europe with a FAA. Or even better if I could get a soda in Europe and get a EASA medical class 1, and become a commercial airline pilot in Europe while being monocular.

I know this has been asked before but that only covers about getting the license, and I want to know if I could get a soda.


texts: What are the FAA's requirements for an experimental type certificate?

texts: What is required by the FAA to obtain an experimental type certificate for a manned prototype aircraft?


texts: Why do many light aircraft have a trim tab on one side of the elevator only?

texts: Most light GA aircraft, like this C172, have pitch trim tabs on one side of the elevator only. Why not on both? Doesn't the asymmetry add inefficiency in the form of a slight rolling moment?


texts:
14 CFR 61.56 (c) requires pilots to perform a Flight Review every 24 calendar months unless another applicable action has been taken in order to be eligible to act as pilot in command of an airplane.

The requirements of a flight review state that a minimum of 1 hour of flight instruction and 1 hour of ground instruction are required to complete that review.

My question concerns the logging of that activity. In the past my instructors have given me an signed logbook entry for the flight time, a description of the training received and materials reviewed a logbook endorsement stating that the flight review was performed. Most logbooks have a section for ground instruction, but I've never logged specific ground time there during a flight review. For a flight review to be valid does the ground instruction actually need to be logged separately from the flight instruction? Or is the ground instruction implied by the endorsement?


texts: What is that missing instrument on a Beechcraft 1900C?

texts:
(Full image) Beechcraft 1900C.

I cannot find the name of the missing instrument even in the manuals.


texts: Why is a (jet) engine in flight shutdown so critical?

texts:
EASA just announced an Emergency Airworthiness Directive grounding all A320neo planes with a certain type of engine. Reason is, that they have apparently the tendency to shut down in flight more often than acceptable.

I was wondering, why are IFSDs so critical? Can't a jet engine be just restarted? If not, is it something with the inherent design of jet engines? Or something that most engines are just designed for?


texts: What is the probability that passengers can survive a ditching in a 747 at MTOW?

texts: Let's suppose a catastrophic EFATO has occurred while climbing out of JFK from Runway 31L, the aircraft is at its MTOW and the best option is to set it down in Jamaica Bay. How long would the aeroplane float and what are the chances of surviving?


texts: I want to become a commercial pilot, can you do that through the RAF?


texts: What is the difference between EFAS and FSS?

texts: What services do each provide and on what frequencies?


texts: How can a part 91 operator gain authorisation from the FAA to perform RNAV (RNP AR) approaches?

texts: How would an individual pilot operating under Part 91 in a light aircraft with a future "glass cockpit" setup (maybe Garmin will add it to the G2000?) capable of coding and flying RNAV (Area Navigation) and RNP (Required Navigation Performance) approaches with the necessary precision and accuracy (incl. Radius to Fix legs) go about gaining authorization to fly them?  Or would such a system require a blanket authorization from the FAA that says that "all users of such-and-such system flying under Part 91 are authorized to fly RNP approaches using the procedure in the system manual"?


texts: What is the meaing of the circuit breaker marking "Audio/Mkr" in a PA-28-181?

texts: On the PA-28-181 that I fly, there's a circuit breaker called Audio/Mkr. What is that? In the aircraft, there's also a dual GNS430 if that makes it any more specific. I was thinking it could be controlling the speaker on the aircraft?


texts: How do piston engines deal with sea spray (saltwater ingestion)?

texts:
From my related question, I want to know about sea spray being ingested into a piston engine during flight. Will this immediately corrode the engine unless there are special materials?

I'm asking this for piston engines, not jets or turboprops. I'm especially interested in WW2-era planes.

Obviously this is primarily about naval aircraft built for saltwater environments, but I'd like to know the protection measures so I can see if a land-based aircraft can be easily modified, or if it's going to need an entirely new engine.

Note: At very high temperatures, corrosion is much faster. I don't know the math for corrosion, but my worry is that sea spray in the engine could cause some cracks somewhere after just a few flights, unless things are made from a much higher (more expensive) grade of stainless steel or aluminum alloy.


texts: Why is the layout of engine data different for CFM vs IAE engines on Airbuses?

texts:
I do a fair bit of simulated flying in consumer flight simulators (and have no real-world flying experience or formal education). Recently, I started putting hours into a supposedly study-level A319 simulation with the option to use either CFM56-586 engines or IAE 2524-A5 engines, and besides some very subtle performance differences and visual changes to the exterior model, I noticed that the layout of the virtual gauges on the upper ECAM display is different between the two models:

With CFM, the four data rows are (top to bottom) N1, EGT, N2, and FF, with no mention of EPR at all -- even if you select the ENG page on the lower ECAM.
With IAE, top to bottom, EPR is prioritized, followed by EGT and N1, with FF and N2 off to either side.

This seems consistent across some other Airbus addons in my simulator, including an A320 which ships only with CFM engines, as well as an A330 which ships with only RR engines, but retains the IAE layout.

What motivates this layout difference, and why is EPR prioritized above other engine data on IAE (and apparently RR) engine configurations?


texts: How turbercle wings could generate aerodynamic advantage?

texts:
Recently it has been discovered that turbercles present in fins from whales are actually providing hydrodynamic benefit for them.

As well, it has been proposed that this effect will provide benefit for airplanes.

From my perspective I can see strong difficulties to see this design able to improve current leading edges, as well, is a design working in water, in a lower Reynolds environment.

My question is actually three:

What is the aerodyamic (or hydrodynamic) mechanism and benefit that these turbercle provide?
How applicable is that to the airplane industry as proposed in several publications? (first thing I see difficulties is the existance of high lift slats and compatibility with these turbercles, probably more applicable to tails).
Which are the potential drawbacks of this design?


texts: Why did moving the CG aft on the Wright Brother's plane improve handling?

texts: In response to Peter Kämpf's answer to this question, why did moving the CG back on the Wright Flyer improve its stability?


texts: What is the structural impact on the wing if no fuel is stored in the wings and just in the fuselage?

texts: What is the structural impact on the wing if no fuel is stored in the wings and just in the fuselage and how to counter possible advantages/disadvantages? Has this topic already been researched?


texts: Which FCC license do I need to operate an aviation radio on the ground?

texts:
I'm in the process of buying a handheld radio as a backup for when I go flying. According to the owner's manual, I'd need a ground station license to operate it when I'm not actually in an airplane, and to fill out FCC Form 406. But, I can't find any information on a "Form 406" on the FAA's website, and the online application has five different options that seem to be aviation-related ("AA - Aviation Auxiliary Group", "AC - Aircraft", "AF - Aeronautical and Fixed", "CA - Commercial Air-ground Radiotelephone", and "CG - General Aviation Air-ground Radiotelephone"), and I can't figure out which one is applicable.
So, if I wanted to use my shiny new aviation radio on the ground, legally speaking, what license would I need?
(I already have a Restricted Radiotelephone license, if that helps.)


texts: What engine power setting is used during cruise?

texts: I am trying to work out what engine power setting is used during the cruise phase of commercial flights but I can't find anything about it in the usual spots. Anyone have any idea what percent of engine power is used? Like 50% engine power maybe?


texts: Why are airliner cockpits not shielded from lasers?

texts:
With the recent increase in laser incidents reported by pilots, why don't airliner manufacturers shield airliner cockpit glass from lasers?

The Abrams tank is shielded, protecting the crew from lasers. Why could a similar process not be employed in airliners?


texts:
This article details the recent (March 2020) grounding of 90% of Ryanair's fleet due to the COVID-19 outbreak.

  Flight tracking data showed that all bar one of the jets had been flown in recent days: 35 had made loops of the airport, while the remaining 11 aircraft had operated a service at least once every four days.

Why are these flights required? The article states this is to keep the aircraft 'serviceable', but the airport I'm learning at has planes that haven't been in the air for months... if they are booked for a lesson, they get a service and away we go.

Why would a budget airline want to spend so much money on fuel and flight crew for these flights, when this could continue for months, it seems like it would make more sense to keep them grounded, and then service them all when this epidemic is over.


texts: How to distinguish the induced drag of a lift-producing wing from its pressure drag?

texts:
Quote John Anderson Fundamentals of Aerodynamics:
"The three-dimensional ﬂow simply alters the pressure distribution on the ﬁnite wingin such a fashion that a net pressure imbalance exists in the direction of V∞ (i.e., drag is created). In this sense, induced drag is a type of “pressure drag."
Wing at 15°AoA  flying in the sky and producing lift same as wing weight...
AXIOM:
Fluid can exert forces at object only in two ways: pressure (normal force) and viscosity(tangential force)
Integration of all tangentional forces at wing ,gives resultant force.Component in backward direction-parallel with freestrem is SKIN FRICTION DRAG
Integration of static pressure over entire wing,gives resultant pressure force.Component of that force in backward direction-parallel with freestrem is PRESSURE DRAG.
What is than INDUCED DRAG, how distinguish induced drag(which is pressure drag) from pressure drag when wing produce lift?


texts: How fast were propeller planes during landing on aircraft carriers during WW2?

texts: I have seen reports of up to 90mph but that seems high?


texts: What's the highest altitude ever achieved by a (rocket-?)plane for level flight?

texts:
As probably most of us know, the SR-71 Blackbird holds the altitude record for leveled flight for (manned) jet planes (and ground-launched planes) at 90,000 ft MSL. However, the very altitude record in leveled flight is probably held by a rocketplane, such as the Bell X-1 or the North American X-15. Is there an altitude record for leveled flight that surpassed that of the Blackbird? What's the record for the highest horizontal flight by a rocket (or any other type of) plane? May include unmanned ones.
Edit: To make it clear, my question asks for the altitude record of a winged aircraft that could sustain this altitude aerodynamically. But Abdullah answered my question anyway, it was the NASA Helios propeller craft (which looks a bit weird but still is a winged aircraft) that reached and sustained an altitude of 96900 ft (29,500 m). Wikipedia says this is the altitude record for aerodynamic horizontal flight.


texts: Why don't airliners use full throttle on takeoff?

texts: It seems that you would use full power for takeoffs, but when I have heard of airline pilots using less than full power on takeooff. Wouldn't it be safer to use full throttle?


texts: What is the range of amplitude of vibration in a helicopter?

texts:
Vibration in helicopter can be caused by many different reasons. I am interested to know what is the range of amplitude of vibration?

I am interested to know how amplitude varies with frequency of vibration? I am looking for an answer in terms of distance from a reference or equilibrium  or stopping condition. For example does the maximum distance (amplitude) from the reference is 2 cm or less or more when helicopter moves?

I understand that it would depend on the helicopter type. So any reference to such analysis would be appreciated.

This is similar/extention to the question What is the range of frequencies of vibration in a helicopter due to the main rotor alone? where it asked about frequency of rotor.


texts: Is it legal to build and fly an international aid drone?

texts:
Is it legal to build and fly a scale 1m:20cm Boeing C-17 for use in flying from the U.K. to other countries to deliver aid in places that are hard to reach?

For example, on top of a large hill where it is hard to get aid workers on foot up there, or too expensive to air drop supplies to people on top of the hill.


texts: How should a private pilot renew their part 107 certificate?

texts:
I got a Part 107 (Commercial Drone) Certificate by passing the test more than two years ago, so it's expired now. I just became a private pilot, and I know that private pilots can get a Part 107 Certificate if they take a few online courses from the FAA.

But since I have the Part 107 from passing a test and now want to use my private pilot certificate to renew my expired Part 107 certificate, how do I do this?

It seems a little convoluted because it's a renewal, not an original certificate.


texts: Experiences with LiFePO4 starter batteries in light aircraft or motorized gliders?

texts:
I am interested in real-life experiences to do with using LiFePO4 batteries in light aircraft and motorized gliders compared to standard PbA ones. LiFePO4 seem to be a very attractive alternative to the good ole lead ballast with regard to weight/size and useable capacity.

Points of interest include amongst others:

Operation safety
Handling (e.g. with regard to charging)
Robustness (electric, mechanical)
Compatibility (electric, fittings etc.)
Cost vs. Benefit assessment
Temperature influence
Life expectancy
Technical / legal admission (e.g. insurance-related)
...


texts: Are there any aircraft that come with interchangeable flightdecks?

texts:
With the new Boeing 787 where Boeing has provided the capability to swap engine types if the aircraft goes to a new operator quite quickly, I'm wondering if there are any interchangeable flightdecks?

Say that you might have a legacy 737 for southwest, but an entirely different cockpit layout (containing the same capabilities) for a company which operates Boeing 787s as well, since the similarities would make training easier.

I know a similar project was done on the DC-10s becoming MD-10s, as well as some Saudi MD-90s to be similar to MD-11, but both of these were long-time consuming projects.

But I'm wondering if there are any aircraft which have this possibility and if not, why not? I'd see it as an opportunity to Boeing to have a 787 flightdeck shared with say the 777.


texts: "Airplane mode" does not disable GPS... is it safe to use GPS in flight?

texts:
I noticed that even when my phone is in "airplane mode", I can still use the GPS.

Theoretically a GPS receiver just receives data, so I guess it would not jam anything.

On the contrary, on the iPhone airplane mode disables GPS, so it means that at least a few engineers at Apple are worried about people using GPS in flight.

Is it really OK to use my phone's GPS in plane, as a passenger of a typical commercial flight?
(when use of electronic device in airplane mode is allowed, obviously)


texts: Relationship between wing aspect ratio and speed

texts:
For some reason, I cannot find a relatively straightforward source online which discusses the relationship of wing aspect ratio and how it affects speeds of an aircraft.

Specifically, is there a decrease in efficiency to fly at a faster cruise speed as the aspect ratio of the aircraft's wing increases? Could an aircraft with a high aspect ratio - similar to those of gliders - travel at the same cruise speed as a jet?

Thanks in advance!


texts: Why does "no aircraft cross directly over the pole"?

texts:
This is from the last paragraph here:

  ... no aircraft crosses directly over the pole – the closest route is
  60 nautical miles (nm) away.

User Michael Shen of York University asked this originally under the article.


texts: How much fuel did this Boeing 787-9 have on board for this flying display?

texts:
Once I saw how an Airbus A350 did a validation flight prior to an airshow and flew back to Toulouse from London Farnborough without landing/refuelling (distance: 550.57 mi (886.06 km)).
I thought that these aircraft must be very light to perform at airshows.
I then saw a video of the All Nippon Airways B787 at the Farnborough Air show 2016.
How much fuel did it carry to perform such a steep climb?


texts: Do the captain's and first officer's rudder pedals always move together?

texts:
I worked on Russian Fighter aircraft where both the Rudder Pedals were mechanically interlinked i.e Captain applies force on his pedal than both pedals (Captain & First Officer) move & vice versa. Single Pedal sensor Unit (of course redundant sensors) senses the position and sends it to the Fly-By-Wire Computer for moving the control surfaces.

I would like to know if this is true for all aircraft (Fighter/Commercial, Boeing/Airbus, etc.) and if not, what are different implementations? Maybe different sensors for Captain/First Officer, different arch etc.

Also on the same lines, how does Pedal Feel operate i.e, does it takes a signal from pilot pedal sensor or from actuators to provide feel to the pilot/copilot?


texts: Is there a pressure rise and velocity change across a turbofan fan and stator?

texts: I've been looking at the pressure / velocity / temperature diagrams across jet engines. These have really helped me to understand the different roles that the compressor/turbine stator and rotors play, and how they compress and then extract energy from the gas flow. I then started thinking about the fan. I've done some reading on how propellers generate thrust in the same way as wings do, with the high and low pressure areas. My question is, do fans primarily generate thrust similar to propellers (i.e. with the high and low pressure areas), or do they operate more like the rotor and stator set-up, with the interaction of subsequent blades acting like nozzles to increase velocity?


texts: Why would aircraft engines be mounted with "toe out"?

texts:
According to Wikipedia, on the Douglas DC-4E...

  [...] the four 1,450 hp (1,080 kW) Pratt & Whitney R-2180-A Twin Hornet 14-cylinder radials were all mounted with noticeable toe-out, particularly the outer pair.

(Emphasis added)

Why would the engines be mounted toe-out, instead of straight in line with the direction of flight? Is this practice common today?


texts: Does the Prandtl flying wing have a lower maximum speed than other designs?

texts:
Does the design of the wing with its "twist" near the wingtips necessarily limit the maximum speed of an aircraft utilising that technology?

Also, with the leading edge profile/attack angle varying along the length of the wing, does this generate any unusual strain requiring complex engineering to accommodate?

( I am a novice here-as I am sure you can guess but a very determined one and I am going to build a Micro Turbine-powered(hopefully!) Prandtl-type wing for myself this year, I may need to consult the many experts here on a regular basis.)

Please try to minimise any mathematical equations in your answers since I’m a bit rusty on my math.


texts: Where can I find records about accidents in the South Vietnam Air Force?

texts:
I don't know if this is the right place for this question, but I guess it's related to aviation right?

My grand uncle was a pilot in the South Vietnam Air Force. He served from 1964 to 1968. He flew F-5s and A-37s and crashed on a A-37.

Being I student pilot now, I very much want to look back and find out what really caused his crash. My family fled Vietnam from the Communists when I was too young. I only remember seeing his Air Force Death Certificate in English which I didn't understand a word in it back then. I was told from multiple sources that his A37 blew up before taking off, and that he crashed soon after take-off... But I always wanted to see the actual result of an investigation if any.

Do you think it is even possible to look up records for those dead ones who served for the South of Vietnam? (since I know they are considered forgotten in the history of the Vietnam War)

The information about the accident that I can remember:
Date and time of the accident: 12/10/1968 9AM
Location: Pleiku Airbase, Vietnam
Aircraft: A-37
Name of pilot: Hai, Le Nguyen (Lê Nguyên Hải)
Pilot's rank: Lieutenant
Pilot's DOB: 12/09/1941

Thanks.


texts: What's the EPNdB for large turbofan engines for stage 5 noise regulations?

texts: I'm trying to estimate the Effective Perceived Noise (EPNdB) of the GE9x. GE Aviation says that it will be within 8 dB margin of the stage 5 noise regulations, can anyone confirm that?


texts: What are the different kinds of de-ice fluid?

texts:
When frost adheres to the airplane or it is snowing, you need to make sure the airplane is clean when you depart.  You've probably seen the trucks spraying aircraft in the winter before departure, but what are the spraying it with?

I know of at least 4 types of de-/anti-ice fluids but perhaps there are others.  What does each fluid consist of and what is its function?  How do I know if these fluids are available at an airport I plan to operate from?  Are there limits in how soon I must depart once fluid is applied?


texts: Can asymmetric thrust occur for Single engine airplane at idle power during stall practice?

texts: As stated in the title: why can asymmetric thrust occur for Single-propeller-engine airplane at idle-power during stall practice?


texts: If a pilot waves back, does it violate the sterile cockpit rule?

texts: There was a video posted to Reddit of pilots waving back from their commercial jetliners. What followed was a discussion of whether or not this was a violation of the sterile cockpit rule. Given that waving back is non-essential communication, is this a violation of the FAA sterile cockpi rule?


texts: Has anyone compiled all the NTSB accident reports and broke down the percentages for cause of accident and fatalities?

texts: I am not talking the typical breakdown such as Pilot/Mechanical/Other, but rather, more specific things such as, engine failure, Stall/Spin on approach, controlled flight into terrain... etc


texts: Have attitude indicators ever had triple failure in a commercial aircraft?

texts:
I'm wondering about couple of well known crashes (mainly AF447 and AirAsia 8501) and thinking: is there any case where triple redundant attitude sensor failure has ever occurred? In those accidents it seems that the pilots assumed that they cannot trust the indicators and forced the airplane to stall to ground.
I understand that air speed sensors can have triple failure (e.g. AF447 had such a situation for a minute) because those depend on measuring external environment. However, the attitude indicators are fully closed system which doesn't require any external inputs. As a result, having failure of three fully independent attitude sensors at the same time looks impossible to me.
Why do commercial pilots keep ignoring the attitude indicators in case other instruments are assumed to have faults?


texts:
I've been doing some research for a uni assignment and I noticed that the RQ-11B uses a "deep stall landing" to get back onto the ground. What I don't understand though is how this aircraft gets into a deep stall, so far every definition of a deep stall that I've seen says that for an aircraft to be in a deep stall, the horizontal stabilisers are in the wake of turbulent air from the stalled main wings. The aircraft in question has high mounted wings and a conventional tailplane, so even in straight and level flight the horizontal stabilisers are below the dirty air from the wings and so when the angle of attack is increased, the tailplane only gets further away from this airflow.

So the main question is, is there another definition of a deep stall that doesn't need the horizontal stabilisers to be in the dirty air from the stalled wing.

This is the aircraft or rather SUAV in question


texts: Do solo night time and “towered” landings total separately toward the solo night requirements in FAR 61.129?

texts:
FAR 61.129(a)(4)(ii) reads as follows for an applicant for commercial airplane single-engine, and makes similar provisions for other categories and classes.

(4) Ten hours of solo flight time … that include -
…
    (ii) 5 hours in night VFR conditions with 10 takeoffs and 10 landings (with each landing involving a flight in the traffic pattern) at an airport with an operating control tower.

Must a solo flight be conducted at night and involve at least one landing at an airport with an operating control tower to count, or do night time and “towered” landings total separately? Given a pilot with five hundred solo night hours all to pilot-controlled airports who goes up at night to fly ten laps around the patch at a nearby Class C, where does that pilot stand with respect to the requirement above?

501 solo night hours and 10 towered landings, or
1 solo night hour and 10 towered landings


texts:
Under normal 2 pilot part 121 ops I could only be scheduled to fly 8 hours in a given day.  This is plenty for the routes we flew (longest leg around 4 hours) so I never encountered the rules for longer flights.

For flying beyond 8 hours -- long haul international ops -- what determines how many pilots must be on board?  Is only flight time taken into account or is the number of timezones crossed also a factor?


texts: What are the symptoms of vortex ring state?

texts:
What are the signs and symptoms a pilot can recognize, that the helicopter is approaching vortex ring state (VRS) and measures should be taken?

A related question discusses how to prevent or recover from VRS, but it does not address the recognition technique. Similar to stalls (which happen unintentionally), being able to identify a worsening situation before the stall fully develops is better than stall recovery.


texts: What does "lower flatness" mean in airfoil terminology?

texts: What does lower flatness mean in these parameters of a Glenn Martin airfoil?


texts: If an elliptically-shaped aerofoil gives the optimum lift distribution, why aren't propeller blades designed around this ideal?

texts:
So given an elliptical lift distribution is the most efficient, why are propellers not designed around this? Props aren't affected by the adverse stall characteristics that concern a "main", elliptically-shaped wing, given they (theoretically) should never stall.
The picture of a C208 propeller below illustrates what I mean; the propeller is raked at the tips. Is this related to encouraging a spanwise flow due to the tips approaching Mach 1? I would have thought stubby propeller blades like those wouldn't reach speeds where wave drag becomes an issue?

I suppose this P-51 propeller is closer to that ideal shape but it is still relatively square at the edges. I understand that you couldn't strap a perfectly elliptical wing to a propeller given the high aspect ratio needed of the blades, but nevertheless, I don't understand why propellers are not at least approximated to the ideal shape...