texts: Can a normally poorly handling airframe with high moments of inertia actually have superior flight dynamics under autonomous control?

texts:
I’m not a pilot but know a thing or two about flight dynamics. As you know there are currently quite a few aircraft under development designed for low-and-slow and (eventually) autonomous flight. These are often referred to as air taxis, eVTOL planes et cetera. Their engineering may require a lot of new thinking but perhaps not. This relies in part on the answer to the question whether they’re designed to be optionally autonomous or exclusively so. My question pertains to aircraft that are NOT to be controlled by humans or only in the case of an emergency, but even then only indirectly through an advanced fly-by-wire system, one probably more advanced than those in modern fighter jets which would be impossible to fly without FBW.
The autonomous air taxis will be more affected by atmospheric turbulence than commercial high-and-fast jetliners and turboprops, and they’ll have to dynamically compensate for this to ensure a smooth and safe ride. To achieve this requires continuous adaptation relying mostly on gyroscope measurements coupled to small to moderate steering actions under autonomous control. Responsiveness is key here and that’s what computers are good at.
So let’s say we’re designing an airplane that’s to be autonomously controlled at all time (obviously with sufficient redundancy). Might for example a plane with a high moment of inertia provide a smoother and at least as safe ride as a “properly” designed airframe designed for manual control? Or do you think the old rules still apply: low(-ish) rotational inertia provides superior handling and passenger experience.
My thinking is that a flight computer that’s programmed to stay within rationally determined limits (to prevent spins et cetera) can fly a plane not just safely but smoother as well. This is akin to how very large ocean vessels are hardly affected by waves and winds compared to small ships. The small vessel is likely to have superior handling characteristics under optimal conditions and yet you'd be much rather off sailing on the large one even if both ships are able to stay afloat in extreme weather.


texts: Is the actual VMC to IMC transition a challenge (for IFR rated pilot/craft etc) if, say, sudden or unexpected?

texts:
I assume that even on an IFR flight, being in even marginal VMC can be helpful, and that pilots consciously or subconsciously use cues such as the horizon to assist them in their flight even though they are principally flying by instruments.

I was wondering if that makes a sudden transition to IMC a psychological challenge, particularly if unexpected. That must be quite a "task switch", scabbling for information, switching focus, and so on?

It seems like that might be much more of a personal challenge than when flying deep in IMC for some time (to a trained and qualified pilot/aircraft) when a routine of going from instrument to instrument is established along route.

Is this a major challenge or a minor or even unnoticeable one in the grand scheme of things?


texts: In simple terms, what are LNAV, VNAV, and Baro-VNAV approaches?

texts:
In simple words, what are LNAV, VNAV, and BARO-NAV?

Are they all precision approaches and will they cancel the traditional approaches?


texts: How many hours of test flight does a general aviation aircraft go through before delivery?

texts:
I'm curious if anybody could give any indications as to how many hours of test flight a factory new small general aviation aircraft* goes through before customer acceptance and delivery.

(Not initial certification, but what is necessary for every new production airframe)

*e.g. Cessna 172, Diamond DA-42 or Robinson R22


texts:
WRT Would the Aeroflot Flight 1492 have been able to dump its fuel first before landing?, I am wondering how much fuel gets dumped every year? gallons? litres? pounds?

Also, is it only in unplanned or emergency situations?


texts: What are the advantages and disadvantages of having landing gear doors?

texts:
To make comparison easy, let us take the example of B737 and A320, both similar aircrafts with retractable landing gear.

As seen on the photo below, the B737 doesn't have gear doors for the wheels,

but the A320 does

Obviously, Boeing and Airbus made different choices for the same feature and both seem reasonable. Both aircraft models are well accepted by the airlines.

What are the advantages and disadvantages of both designs?

EDIT: I put links to other images where both aircraft are retracting landing gear after take off. The difference is obvious as we can see the landing gear doors operated for the A320 and no doors for the B737's wheel.


texts: Is it an overkill to request to see airplane maintenance logs at a new flight school?

texts:
I'm getting a checkout at a new flight school, so I don't know anything about the maintenance records of their airplanes other than this school has been in operation for some time and so I assume everything is in order.  As PIC, though, I would think I would feel better seeing for myself that this plane I have never flown before is indeed up-to-date, at least in its required inspections.  I've never had an urge to do this before, I've always just trusted that the flight school is running things properly, but I guess since I have quite a bit more experience since my last checkout I felt like looking into this would be judicious.

Is this overkill?  Would it be taboo or send a message of distrust to the school if I asked to see the mx logs on my plane I'm getting checked out in?  Does anyone make it a point to do this?  Thanks in advance for your comments.


texts: Why doesn't the US have a flag carrier airline?

texts: With the recent United Airlines fiasco, I was reading up on their history and the airline industry and to my surprise I found that United Airlines is not the US flag carrier. In fact, the US does not have flag carrying airline at all! All this time I thought UA was the national carrier for the US. This brings me to the question, why? Why doesn't the US have a national carrier? Is this because of some FAA regulation?


texts: How can we do the complete lateral, longitudinal, and directional stability analysis of an aircraft by drawing appropriate geometry? I tried DATCOM+ but it has certain limitations. Is there any other way that can give you 90% accurate results? I have also tried Aircraft Intuitive design MATLAB toolbar but that gives us only longitudinally stability analysis.


texts: Instrument Approaches which do not have a FAF

texts:
Most instrument approaches denote the Final Approach Fix (FAF) as the start of the final approach segment terminating in either the Missed Approach Point (MAP) for non-precision approaches or a Decision Altitude (DA) for a precision approach.  On IAPs the FAF is designated either as a Maltese Cross for non precision approaches or as lightning bolt where the glide slope intercept occurs on a precision approach.  That’s all fine and dandy until I encountered this IAP.

There appears to be no FAF designating the final approach segment.  What does this mean?  Are the FAF, the IAF, and the MAP all coincident?
UPDATE
Someone here suggested that this was because the VOR Rwy 27 has straight in minimums.  However that does not appear to be a general rule.  For instance, take VOR Rwy 01 into KSAV.

This approach has straight in and circling minimums yet clearly has a FAF FREMN defined and located by either a DME or GPS.


texts: Engine Oil Consumption limits part of certification?

texts: Does anyone knows if Engine Oil Consumption limits are part of the engine certification requirements?


texts: Do airlines have contingency plans to keep passengers warm in the event of an Arctic emergency landing (or otherwise a diversion)?

texts:
Imagine you're flying to Los Angeles in February, but find yourself landing in Iqaluit instead, with a daily mean of −27.5°C, without considering the effect of wind.  Even walking from the cabin to a runway bus may involve sufficient exposure to cause serious injury if passengers (and crew) are dressed for +20°C.  Most intercontinental flights pass over high latitudes, so a high-latitude emergency landing can't be that exceptional.

Are airlines required to have contingency plans to keep passengers warm in such an event?  There wouldn't be space to stock lots of bulky fur coats on a plane, but groundside there would be.


texts: Why do jet engines use kerosene rather than gasoline?

texts: Could you run a jet with gasoline? Why do all jet engines use kerosene?


texts:
One thing I saw on the news recently was the following image:

How has this happened?

Some details:

British Airways A380-800.
Flight BA-32 from Hong Kong to Heathrow.
While climbing out of Hong Kong crew received a tyre pressure notification, but continued on as the A380 can land with 1 of it's 18 tyres flat.
Landed safely, but had to request a tug to the gate.
The photo above is after landing.

I can't seem to find a clear explanation to why the tyre has gone this square shape. Generally when a tyre is flat it's round with the bottom being straight. The explanations seem to vary between tyre pressure, to the way it lands, to the way it is stored.

What's the real reason it's square?

http://avherald.com/h?article=498050d8


texts: What is this airplane that sits in front of Barringer High School in Newark, NJ?

texts: This airplane sits in front of Barringer High School in Newark,Nj. No one there can identify it. Anyone have any idea of the make and model? Thanks


texts: How do I simplify explanations for the drag formula?

texts:
With reference to aircraft aerodynamics:

As the aircraft speed increases the aerodynamic load increases in a
mathematical relationship proportional to the air density and the square of
velocity.

What does the above statement mean in layman's terms? Consider explaining it to a high school student.
Also, what's the simplest explanation for the drag formula too?

Fd=1/2 *Density *Velocity^2 *Coeff. drag *Area


texts:
I am currently trying to understand 61.57 and it’s instrument currency requirements for pilots. I have made some 2 scenarios here, and it would be great if I could get some feedback to my questions.

Scenario #1
In this one, I have completed 6 instrument approaches and one hold in March. By counting back, I am current until the end of August 31. My question is how many approaches do I have to do in September to regain my currency if I am trying to act as PIC during IFR in that month?

Scenario #2
This is where I get a little confused. Say I did 5 approaches and one hold. Because I didn’t do a 6th approach, when am I not current? Also what is the staring date of my “6 month grace period?” And alternately, if I did not do anything during the grace period, what is the date when I must do and IPC check?


texts: How do pilots get enough sleep in preparation for a long night flight?

texts: Are pilots authorised to use sleeping pills to rest before long haul flight that departs at night hours? This question comes in mind as I have flown Turkish Airlines flights that depart at 2.30 at night arriving in the morning with the duration of the flight of about 8 hours. Since the pilot or the co-pilot have to be awake (I suppose, at least one of the 2..) during the flight they will have to get good rest during the day. Sleeping during the day is quite difficult and not natural and this is where my question comes from. If not, what remedies do they use?


texts: Considering all US untowered airports, what is the furthest distance that E2 airspace (dashed magneta line) projects from the airport?

texts:
Considering all US untowered airports (50 states), what is the furthest distance that E2 airspace (dashed magneta line) projects from the airport for which it is designated?

Measure from the middle of the airport, or if the airspace is officially defined from a navaid or other feature that lies on the airport, measure from that navaid.

Example of E2 airspace -- KONP-- http://vfrmap.com/?type=vfrc&lat=44.580&lon=-124.058&zoom=10

On this airport, only the inner circle is E2 airspace.  The outer projections are E4 and don't count for this question-- http://vfrmap.com/?type=vfrc&lat=38.894&lon=-119.995&zoom=10

Beware these 3 airspaces, they are special anomalies, they appear to be all E2 but the projections are actually E4 (see related question Why are KACV and KTLV depicted differently on sectional charts than KSGU, KBIH, and KTPL, even though each is E2 w/ E4 extensions? ).  To my knowledge these are the only 3 of this kind:

KSGU -- St. George Regional Airport, UT -- http://vfrmap.com/?type=vfrc&lat=37.036&lon=-113.510&zoom=10

KBIH -- Bishop Airport, Bishop CA -- http://vfrmap.com/?type=vfrc&lat=37.373&lon=-118.364&zoom=10

KTPL -- Temple, Draughon-Miller Central Texas Regional Airport, TX -- http://vfrmap.com/?type=vfrc&lat=31.152&lon=-97.408&zoom=10

Except for these three anomalies, you can generally assume that a dashed magenta line surrounding the airport whose approaches it protects, with no inner dashed magenta line, denotes E2 airspace.

Don't be shy about posting the longest answer you've found -- if someone else posts longer no big deal.

Give you best guestimate by measuring on sectional, or check this document for the actual airspace description-- E2 airspaces are listed on pages E-2 through E-141 and have "E2" in the heading, like this:

"ANM OR E2 Newport, OR
Newport Municipal Airport, OR
 (lat. 44°34'49"N., long. 124°03'28"W.)
Newport VORTAC
 (lat. 44°34'31"N., long. 124°03'38"W.)
Within a 4-mile radius of the Newport Municipal Airport, and within 3.5 miles each side of the Newport VORTAC 357° radial extending from the 4-mile radius to 7.9 miles north of
the VORTAC."

In any case of doubt, use the document linked above to definitively determine for which airport the E2 airspace in question has been designated.

State whether measuring in nautical miles or statute miles

The document above uses nautical miles (p. A-2).


texts: Does using a reverse high Cm horizontal tail airfoil coupled with a low Cm wing increase horizontal tail effectiveness?

texts:
Does using a high Cm reverse horizontal tail airfoil coupled with a low Cm wing increase horizontal tail effectiveness?

Just noticed that the Zenith 701 wing uses a NACA650-18 which is low $C_m$, while their inverted horizontal stabilizer uses a NACA4412 foil which is a high $C_m$ foil. They could just as easily have used a low cm NACA0018 or NACA2415 foil with a slotted elevator to get the same $C_L$, but they chose a high $C_m$ foil instead

I'm assuming using a low $C_m$ wing and a high $C_m$ horizontal tail adds to the effective moment produced by the area of the horizontal tail, allowing for a smaller horizontal tail area.

Is this correct?


texts: How did this incident report detailing a flight taking off and landing at Glasgow result in safety changes at a distant airport?

texts:
While reading this report detailing a tire failure and actions taken, I noticed a peculiarity: The flight took off and landed at Glasgow without continuing to Malta (its intended destination) yet the Actions taken says:

  For flights from Malta, takeoffs to be carried out with flaps 5 only.

How would the operator find an issue with flights out of Malta for a flight intended to land in Malta, that never did (by virtue of returning to Glasgow)? Is it policy or practice to check all aspects of the flight including those that were not reached due to the incident? Was something not mentioned likely to have been found at Malta (perhaps damage from a previous takeoff)?


texts: What happens after a clearance or an instruction has been sent by ATC using CPDLC?

texts:
With conventional ATC, an instruction or a clearance is broadcast using voice, in case of no response from the crew, it can be repeated, and if silence persists it can be discarded as if it was never transmitted by ATC.

For aircraft with appropriate equipment, ATC can use CPDLC (controller-pilot data link communication). The message is sent and can be displayed by the crew. Then the crew may accept it or reject it, which is equivalent to the voice protocol.

Source

However what happens in case:

The crew doesn't open the message.
The crew doesn't answer the message after opening it.

Will ATC use voice to ask the crew to expedite responding to CPDLC instruction?

For ATC, how long this message remains valid? Can a message already sent be cancelled?


texts: Why is the ILS 36R approach at ZBAA over twice as long as a standard ILS approach?

texts:
I fly exclusively in a consumer flight simulator, so excuse me if there's an obvious answer to this.
ILS approach plates typically show a long, arrow-like symbol to indicate the part of an approach path where the localizer and glideslope signals can be captured by an approaching aircraft; most often, when there are no natural or manmade obstacles, for 3º glideslopes, this is about 9nm out from the threshold and 3000ft above the touchdown zone.
Looking at a chart for ZBAA's ILS 36R approach (which I'm not sure I can include in this post since this would likely violate Navigraph and/or Jeppesen's ToS), 36R specifically has this arrow extend out twice as far as either 01 or 36L — to about 25.5nm and 6890ft above the deck.
Why is this, and how common are such extended ILS approaches elsewhere in the world?


texts: Could you land a large airplane on short circular runways?

texts: Considering that building runways is expensive and that they take up a lot of space, could you land a large commercial airliner on a circular runway, braking as you go around the curves?


texts: What is the beeping occasionally heard in the background of ATC?

texts:
Occasionally while listening to ATC, I hear a beeping in the background of their transmission. My suspicion is it's a traffic conflict alert since the beeping is usually followed with a traffic alert to a pilot. But other times I've heard the beeping without a traffic alert.

Here is a short snippet from today of Norcal Approach at KOAK demonstrating the beeping heard in the background: https://vocaroo.com/lD93L8D5lJ3


texts: How do airlines (or the government) retrieve information from the black box of an aircraft?

texts: When black-boxes are found, how is the information retrieved from within the data storage?  Is there a special kind of device used for this?


texts: How to refute this geometrical method to find MH370?

texts:
A geometrical method to find MH370 has been published on the Net (see images below).

I am sure it is wrong (because if it were that easy, thousands of people would have had this idea back in 2014). However, it has attracted some attention.

My question is:
How can this method be proven wrong in a simple, straight-forward way ?

Here is the method:

source: This method was first presented here.

EDIT:
How is this question off-topic while How can a computer model yield two possible flight paths of MH370 in South Indian Ocean? is on-topic? Isn't this having it both ways?


texts: How do I remind myself to run in-flight checklists?

texts:
When flying a basic light aircraft with no "modern" instrument the pilot needs to remember to do various checks on a regular basis (FREDA every x minutes, change fuel tank every Y minutes etc.).

Just flying the plane can be consuming a lot of attention (especially without auto-pilot or if you become unsure of your position) and it's easy to forget to run those checks. I wouldn't want to forget changing fuel tank so I was wondering:

What are the tools that I can use to make sure that all checks are done on time?


texts: What is the best procedure for landing at my destination if I have a full electrical failure at night?

texts:
What is the best procedure for landing VFR at the intended destination airport and I have an electrical failure, in the following scenario?
Let's assume this is a VFR flight and I'm 50 miles from the departure airport in the United States, which is a cross country flight. There is no issue with the weather. I have noted no issues with the Cessna 172's electrical power at run-up prior to takeoff, I have at least an hour of fuel reserve and meet all the 91.205 requirements.
I then experience an electrical failure during the en-route phase to the intended destination airport, and I have done the necessary checklist to try to solve the issue but it doesn't fix the problem. As I approach the vicinity of the airport, I key the mic seven times (high intensity) and no runway lights appear. I expect it is too risky to land on the road because there could be power lines nearby.
I found the following scenarios on the internet but they don't answer my question:

Pilots flying to a towered airport (still open at night) with full electrical failure, squawking 7600, and waiting for ATC's light gun signals to appear.
A pilot has the same issue and is lucky when a plane turns on the runway lights and lands before him, but he doesn't commit an emergency
The pilot is lucky at landing at a towered airport that is closed while the lights are still on, but the lights turn off or dimmer to pitch-dark as he begins to land

I came up with my scenario myself because I can't find information about it on the web. It would help me if you could provide suggestions and tips on what I should do or not do when this happens to me in the future.


texts: What happens when a pilot is incapacitated?

texts:
Is there a contingency for such a situation, where one of the pilots leaves the cockpit, the other pilot is incapacitated (for example losing consciousness) while the first pilot is still outside the cockpit and can not reenter the cockpit. If there is not, is that not a huge flaw, as multiple pilots are meant as a redundancy.

Edit: This is in my opinion not a duplicate of this question, since the big problem in my question is the door to the cockpit being only openable from the outside.

In the linked question, the answer is simply "both pilots being incapacitated at the same time is highly unlikely". The scenario I described is not highly unlikely. One of two pilots being incapacitated is not improbable and the door to the cockpit is only openable from the inside.

So if one pilot is incapacitated while being temporarily alone in the cockpit, the other pilot is "automatically" locked out of the cockpit.


texts: Is FAA's Order 8260.58A complementary to the TERPS manual as far as SID design is concerned?

texts:
I am studying FAA's United States Standard for Terminal Instrument Procedures (TERPS) to learn how a SID is designed and what kind of rules and constraints one has to take into consideration. I am also studying the PBN Instrument Procedure Design manual (Order 8260.58A), which describes the instrument procedure design for Performance Based Navigation procedures.

However, chapter 14 of the TERPS manual, titled "Departure Procedure Construction", makes no mention of the Order 8260.58 (only once at the beginning for RNAV-equipped aircraft criteria) and proceeds to describe the departure procedures construction as if the Obstacle Clearance Areas that calculates apply to all kinds of departure procedures, without any notice that e.g. "For PBN procedures, consult Order 8260.58".

Could someone help me to clarify how to interpret these two manuals correctly, at least as far as the design of departure procedures is concerned? There seem to be so many rules related to this particular subject and I got a bit lost.


texts: What type of engines are used on the RNLAF KDC-10 and KC-10's?

texts: Does anyone know what type of engines are used on the Royal Netherlands Air Force's KC-10's/KDC-10's? I did some research and found out that they are GE CF6-50 engines, but what comes after the "50"? Is it a -50C2B, for example? Or a -50A?


texts: What makes the perfect landing in a tail-dragger?

texts: What is the 'perfect landing' in a tail-dragger? Do you try to float down to a main-gear landing at minimal descent speed, or do you attempt to float to the point where your tail will either start to come down, or does come down? In other words, is a two-point touchdown or a three-point touchdown more 'perfect.'?


texts: Why are these steps performed on the A330 emergency electrical checklist?

texts: For an Airbus A330 in emergency electrical configuration with both generators and APU FAIL (both engines working), why does the checklist ask you to select RAT MAN ON before slat extension and then LAND REC ON?


texts: What priority if any is given to Emergency Services in flight clearance?

texts: When requesting takeoff/landing and route clearance is any priority given to Emergency Services IE air ambulances, firefighting rigs, S&R etc. I'm assuming even though these services rise to the level of life or death, they are not treated with the same urgency as an air emergency but I don't know that for fact.


texts: Why didn't NWA 85 request/receive fighter jet help with their mysterious rudder failure?

texts:
I recently watched a documentary about the Northwest Airlines Flight 85. The flight experienced a grave rudder malfunction when it was over the Bering Sea and had to turn back for an emergency landing in Anchorage, from which it was about two hours away.

The captain has been quoted:

  I would have given a thousand dollars for a rearview mirror. The self-diagnostics of the airplane which normally are pretty good, in this case basically told us nothing. And the control position indicator was really the only indication that we had had that the rudder was malfunctioning. The tail could be coming apart for all we knew. And if it came apart, we probably would lose the airplane...We were just going to have to figure this out.

So, they had something wrong with their rudder, but couldn't figure it out. Wouldn't it have helped if they had the pilot of another plane come and see it?

Since they were heading for Anchorage, couldn't they or the air traffic control have called the Elmendorf Air Force Base and asked for a fighter jet to come and see the rudder of the Boeing 747-400? There would have been plenty of time, since they were some two hours away from Anchorage. You'd also think that each Air Force base has a fighter jet that's able to get to air at a moment's notice. A jet would've easily been able to meet them in the middle and take some photos of the rudder.

There were some 400 people aboard the NWA flight, so it's not like it was a minor issue. For all anyone knew, the plane could've crashed into the ocean at any moment. At least a fighter jet pilot would've been able to pinpoint the exact crash site for a search party later on. What am I missing?


texts: Can I get an EASA class 1 medical if I am red/green color blind?

texts:
When I got the Class 2 certificate(one week ago), AME told me that I am red/green color blind and the certificate is valid by day only. Is it possible for me to pursue an aviation career and pass the Class 1 certificate?
I failed almost all red/green Ishihara plates. I heard something about a test called CAD, and if I pass this test I can continue but im not sure.


texts: Sometimes I am asked to give-off my cabin luggage case at the gate and it will be returned to me upon arrival. I often don't mind, as long as I do get it back at the gate upon arrival and don't have to go to the baggage pick-up belts. Is this luggage stored in some particular place (so I can be more assured the gate drop-off won't delay me)?


texts: What is the behaviour of ILS when there is an unmodulated interfering carrier signal?

texts: Let us assume we have a localizer (identifier I-STK) transmitting at 110.10MHz and a matching glideslope at 334.40MHz.  If a device aboard an aircraft tracking the I-STK ILS were to emit an unmodulated interfering carrier on either of those frequencies that is then picked up by the ILS receiver's antennae, with enough power to render the LOC or G/S signal unreceivable, would the pilots see a consistent wrong indication, erratic/wildly changing indications, or a FAIL flag?  Would the behavior under this circumstance differ between glass and round-dial aircraft cockpits?  Also, would the ILS Morse identifier be rendered unreceivable before or after the cockpit indications fail?


texts: Is it possible to change/repair an aircraft tire while in flight?

texts:
Consider the following scenario: A crew experiences a flat/burst tyre above V1.

Is it possible, in some type of aircraft, to change it while in flight?

This might include, but not limited to:

access the landing gear compartment
access hydraulic operated equipment
changing the damaged tyre


texts: What is the difference between "Bay" and "Stand"?

texts: When should we use the word Stand and when Bay for ATC taxi clearance?


texts: What is the time derivative of the angle of attack?

texts:
Suppose a flying missile's velocity vector has components $u, v, w$, as illustrated below.

From my knowledge of flight dynamics, the angle of attack is

$$\alpha = \arctan \left(\frac{w}{u}\right)$$

where $u, w$ are time-varying. Then,

$$\frac{d\alpha}{dt} = \frac{1}{1+\frac{w^2}{u^2}} \left(\frac{w}{u}\right)'= \frac{w'u - wu'}{u^2+w^2}$$

Some books indicate

$$\frac{d\alpha}{dt} = q + \frac{Z}{mu}$$

where $q$ is the second component of angular velocity, $Z$ is the third component of the total force, and $m$ is the mass of missile. How can these two formulas be the same?


texts: What kind of sunglasses are good for flying?

texts:
I'm a beginner at aviation. I'm currently in training for gliders license.
Our instructors mentioned that sunglasses are very important if not mandatory.

What kind of properties do I need to look for in sunglasses to determine whether they are good for flying?


texts: Are commercial pilots incentivized to reduce fuel consumption?

texts:
Commercial airlines spend a lot of their operating income on fuel, so in order to maximize shareholder value presumably like to use as little fuel as is safely possible.

Are commercial pilots ever given incentives (e.g. financial, performance review) for reducing fuel usage, or given dis-incentives for excessive fuel usage?


texts: What is the effect of Mach number on efficiency, thrust and specific fuel consumption of a ramjet engine?

texts:
My graphs show that overall efficiency and thrust first increase, reach a peak and then fall in the supersonic range (M=1-5) whereas SFC first drops and then increases rapidly near M 5.
Why does this happen?


texts: Why do gliders have bungee cords in the control systems and what do they do? Are they on all control surfaces? What about ultralights?

texts:
Why do gliders have bungee cords in the control systems and what do they do?

Are they on all control surfaces?

Why don't ultralights have them?


texts: How should I log time when I fly from one airport to another and back again without landing?

texts: How should you log flight time when flying from airport A to airport B and return to airport A without landing at airport B?


texts: Why do aircraft (namely military) need/use formation lights?

texts: Why are formation lights used,and why are they largely/always used only on military aircraft and not civilian?


texts: Power changes and trim forces. related to position of Center of Mass (CoG), or Center of Pressure?

texts:
Theoretically (and Actually) do power increases cause a pitching tendency (and a need to adjust pitch trim), because the thrust line is not aligned with the Center of pressure, or, as I understand it, because the thrust line is not aligned with the center of mass (CG)?
I was recently told that the Cessna 182 is particularly sensitive to abrupt power changes in the landing phase (at slow airspeed) because it is a high wing aircraft, and the thrust line is below the Center of Pressure. i.e., Increases in Power generate a pitch up moment, requiring down trim to compensate, and reductions in power generate a pitch down moment, requiring nose up trim to compensate.
This strikes me as wrong, I believe it the alignment of the thrust vector with the center of mass of the aircraft, (the Center of Gravity (CG) as it is called), that determines the moment generated by thrust vector.


texts: Tracking freighter and charter planes between two specified airports

texts: Is there a way to find the historical data of the freighter and charter planes between two airports


texts: What is the difference between leasing and chartering?

texts: As written above, what is the difference between leasing and chartering? Is it the same thing and if not what are the differences?


texts: What requirements are there for radio systems in aircraft?

texts:
What are the requirements for radio systems in aircraft? For example, are there requirements about:

Reception ability
Transmit ability
Transmit power

This is primarily about voice communication systems, but information about other radio systems is welcome as well.


texts: Why do aerobatic aircraft have separate tanks instead of a single acrotank?

texts:
I've been reading about fuel tanks in aerobatic planes such as the Extra 330, Edge 540, XA41 and I don't really understand why in the Extra 330 there are separated center tanks and an acrotank instead of a single bigger acrotank like in the Edge and XA41.

I guess it's something related with balance and center of the aircraft but the Extra has two center tanks and their relative positions between them and with the acrotank are small.


texts: Are go-arounds prohibited at St Barth (TFFJ)?

texts:
The description of this video claims that past a certain point — which is around the turn to final — on approach to TFFJ (St. Barth) runway 28, a go-around is prohibited. That sounds strange. I understand how going around might be impossible past a certain point at VNLK (Lukla) or LFLJ (Courchevel), because the hill ahead is too steep to outclimb and too close to turn away from. But while there is a small hill beyond this runway too, it should be low enough to outclimb to much further. So:

Is a go-around prohibited past a certain point on approach to TFFJ runway 28?
If yes, it is prohibited from as early as the video suggests (around final turn, still well above the hill beyond the runway)?
And if yes, what are the reasons for it?


texts: Is this type of wing design structurally sound?

texts:
Is the simple wings
frame(spar,ribs)of this maxair hummer structurally sound? I am asking because I'm considering using thesame wing design on my homebuilt ultralight.


texts: How can I figure out the take-off minimum when multiple minimums are listed in the TPP?

texts:
For example:

If the published take-off minimum depicts:

  Standard with minimum climb of 565' per NM to 2800, or 1000-3 with
  minimum climb of 370' per NM to 2800, or 1500-3 for climb in visual
  conditions.

How can I figure out which of the various minimums apply? For example, if the airport has 1200-6, which of the available take-off minima can be used? Could you explain in detail and why?


texts: What would the call sign of a non-standard aircraft carrying the US President be?

texts:
So, it's well known that the government planes operated for the US President are called Air Force One; less well-known is that this is a call sign given to any Air Force aircraft that carry the president, and that if the President rides in an aircraft owned by another branch of the US Armed Forces, they would become known as Marines One, Navy One, or Army One, while any civil aircraft that carries the US President becomes Executive One.
What about aircraft that are exceptions to the normal FAA rules for aircraft licensing, however? If the US President was riding in (or piloting) a glider, ultralight, or autonomous drone taxi, what would their call signs be, if any?


texts: What are the requirements to convert a license from Iran to USA?

texts: What is required for someone who has CPL, IR and CFI licenses from Iran to fly in USA? What is the requirement to convert license?


texts: Could modern military aircraft be retrofitted to work with alternative fuels instead of kerosene?

texts:
I am geologist and I have heard in 50 years petroleum will be nearly gone.
I know for commercial planes there are working projects with clean energy.
I can be wrong, but I think military systems would fail with no kerosene maybe in 30-40 years, as petroleum is becoming much more expensive to extract and its quality is falling.

So I wonder what's the sense of buying military appliances at 2018.
I don't know if kerosene is being stored by the armies, but I wonder if it is just a madness to give the reason for increasing military budget.

I am asking also what is the future for fighter planes etc. When petroleum is finished, is there any possibility to create technology that works with nuclear energy or so or this is the end of war?


texts: How turbofan engine efficiency increases over altitude or speed?

texts:
I am confused a lot about the efficiency and thrust relation with altitude and velocity of an  aircraft.  If thrust is related to air mass flow and velocity diffrence of bypassed air - exhaust gases and intake air velocity, then thrust will decrease as altitude increases which is true as CFM56 stationary thrust is 140kN while at cruising altitude it is 24kN. Everyone points out that the efficiency is higher at higher altitudes, but how?
Yes fuel flow decreases too to maintain O/F ratio but what about the reduction of thrust?   Does propulsive efficiency goes higher too? And how the aircraft can still maintain its speed with 1/5 of the thrust at TO,  someone also pointed out drag actually increases with higher altitude and speed, is it true?


texts: Is there any "copyright" for aircraft's design between different manufacturer?

texts: Are there any regulations for the copyright of aircraft's model design between competitors in the aircraft industries? Basically is there a regulation for avoid that one company just steals the project of a competitor to produce a version very close to the original?


texts: Is there a dedicated emergency frequency?

texts: Coast patrol has a dedicated frequency for emergency that must be watched at almost all hours, and even if I recall, it had a "dead silent period" to prioritise whatever emergency might be reported. Is there a dedicated frequency for aviation? Or shall MAYDAYs just be sent to the standard ATC frequency?


texts: What is the difference between autopilot and autoflight?

texts: Can you please give me some explanations about autopilot and autoflight system?


texts: How to calculate the distance between two waypoints on an approach plate?

texts: Can you please show me how to calculate the distance between the 2 waypoints A and C as shown on the picture? I would really appreciate it. I am having difficulties to calculate the distance between 2 waypoints.


texts: Can an aircraft or helicopter run into its own wake vortex?

texts: I was recently flying my rc helicopter and I would sometimes turn it around and move it forward and sometimes I lost control of the helicopter while doing that a few times and crashed it everywhere (accidently crashed it into my poor cat). Every time I fly this helicopter it randomly starts turning to the left uncontrollably. Also I have had where I kept the thrust at the same level and then I would fly it into a different room and it would start raising in altitude uncontrollably. So can a helicopter or aircraft fly into its own wake and was it the wake of the helicopter that caused these problems with my helicopter?


texts: Why do landing gear tires smoke upon touchdown?

texts:
I have been observing several aircraft landings and have noticed that when the aircraft's landing gear touches down, it precipitates the rising of a cloud of smoke. Why is this?

(Source: airliners.net)


texts: What is this object in the cockpit of an ultralight?

texts:
This is a tool (probably) in on an ultralight airplane. Initially I guessed that it is a tilting meter (to level between right and left), but seems it is not as it just a vertical tube filled up with something like liquid.

So, what is that and how does it work?


texts: Is it possible to prevent/avoid laser beams with new technologies on windscreem?


texts: How does a taildragger take off? Does it rotate?

texts:
All the planes I've ever seen taking off (big airliners) first lift the small front wheel from the ground, then rotate and ultimately lift up.

If the small wheel is on the tail instead, in which sequence are the wheels lifted from the ground? Lifting the tail wheel first would pitch the plane down, so the sequence is most likely different.


texts: What is the name of the figure consisting of a slow revolution around longitudinal axis?

texts:
"An airplane performing one slow revolution around its longitudinal axis is performing one of these..."

This was a clue on Jeopardy today. The contestant responded with, "What is a barrel roll?" which I contend is incorrect. But he earned $2000 for it.

My response would have been: "What is an aileron roll?" Is he correct, am I correct, or are we both correct?


texts: Is extreme wind shear an official classification? Is it rare to land in 65kts headwind, gusting 95kts?

texts: I was a passenger in an A340 during a famous storm 65kts gusting 95kts. Resulted in a go around, but the plane sunk quite fast several times. Is this rare? Are there limits to headwind component? The captain said we experienced extreme wind shear, is that an official grade? Checked the metar for the kts.


texts: Why do VTOL aircraft (F-35 or Harrier) have only one engine? Is it because it is simpler and less expensive? Or what are the reasons?


texts: Why is London City getting a virtual tower?

texts:
(Source)

London City is not a remote-low-traffic airport. Staffing a remote airport is like having lighthouse keepers. That I understand.

And yet the tower will be closed, and moved off-airport to become a virtual tower.

All those working on the project are very happy apparently, and the press releases (and videos) don't reveal much. I don't get it. The only thing that I saw as a positive, was an augmented reality overlay on the screens that highlights nearby drones.

  (...) a critical new safety feature means the cameras will be able to pick out rogue drones near the airport, as well as light the runway at night.

Why would a major airport undergo such change? What problems are being solved?


texts: Which items are allowed on passenger flights but not on cargo ones?

texts:
I've only ever sent items by air in suitcases accompanying me in passenger flights. But - I'm about to send some items on a cargo-only flight in a few days. I've been told:

  Make sure that there are no dangerous goods in the shipment please (batteries, aerosols, perfume etc.)

while on passenger flights, you can definitely have batteries, aerosols and perfume in your hold luggage. You can even have that in the cabin under certain limitations.

So, my question is: What is the specification of which materials are forbidden for air transport in cargo flights as opposed to passenger flights? And is there a globally-accepted standard for this, or is it airline-by-airline?


texts: How do manufacturers/kit providers determine Vne?

texts: Vne defines the maximum indicated airspeed which should not be exceeded. And clearly, doing so would result in "bad things" happening like flutter, etc. Presumably manufacturers do some sort of design work to determine likely Vne but how do they test for that? Exceeding Vne would put the aircraft into a structural failure situation would it not?


texts: Where are the first two waypoints for runway 4R departures from KBOS?

texts: Departure way points for Runway 4R at Logan Airport in Boston Massachusetts. Can anyone send me a map depicting where the first 2 way-points are for 4R Departures?


texts: Is there a way to fly an UAV over a roadway?

texts: With an FAA Section 333 Exemption, they will permit you to fly up to 400' above ground level. But they also restrict you to flying at least 500' away from people and vehicles unless you have their permission. You can't get permission from every vehicle driver that happens to be passing by. Does this effectively mean that there is absolutely no way to fly over a public roadway, or is there another exception or reasoning to be able to do this?


texts: How does the wraparound wing design reduce drag?

texts:
How does the wraparound wing in this AOPA article reduce drag?  One would think all that extra leading edge and surface area would make it worse.
One more link also.

  The Parsifal Project has produced a proposed design dubbed PrandtlPlane, an homage to Ludwig Prandtl who developed an idea for an airplane wing that boosted efficiency (and reduced drag) by wrapping around on itself to form a box around the fuselage.

This paper on Conceptual Design of High Subsonic Prandtl Planes

Title: Conceptual Design of High Subsonic Prandtl Planes

Author: Zohlandt, C.N.

Contributor: La Rocca, G. (mentor)

is also proving to be most interesting reading


texts:
The logic of ECU to hold N1 with fuel flow follow the logic:

Idle N2------------N2 set ,N1 floats
min ps3 schedule -----------N1 and N2 float

So what does this mean? And does the float here with the same meaning of the float display on the UPPER ECAM?


texts: What is the minimum speed at which the Antonov An-2 can maintain level flight?

texts:
The An-2 famously has "no stall speed", as control can be maintained in descent at arbitrarily low airspeed. As wikipedia says:

The An-2 has no stall speed, a fact which is quoted in the operating handbook. A note from the pilot's handbook reads: "If the engine quits in instrument conditions or at night, the pilot should pull the control column full aft and keep the wings level. The leading-edge slats will snap out at about 64 km/h (40 mph) and when the airplane slows to a forward speed of about 40 km/h (25 mph), the airplane will sink at about a parachute descent rate until the aircraft hits the ground."[4] As such, pilots of the An-2 have stated that they are capable of flying the aircraft in full control at 48 km/h (30 mph) (as a contrast, a modern Cessna four-seater light aircraft has a stall speed of around 80 km/h (50 mph)). This slow stall speed makes it possible for the aircraft to fly backwards relative to the ground: if the aircraft is pointed into a headwind of roughly 56 km/h (35 mph), it will travel backwards at 8.0 km/h (5 mph) whilst under full control.

But there has to be some minimum speed at which it can generate just enough lift to counteract gravity, what is this speed (and does it have a general name)?


texts: What's the north boundary of the KINS Class D? (Or: does a SUA designation take precedence over controlled airspace?)

texts:
This is inspired by the question regarding aerobatics over a surface class D area.

KINS (Creech AFB) sits right outside the south boundary of the Nellis Range Complex (R4806W to be precise).  Considering this, and considering that it has surface Class D around it whenever the tower's open as per the A/FD...does that class D airspace abruptly end where R4806W begins just north of the airbase, or does it continue all the way around, leaving a portion of airspace that's both a Class D (sfc) area and SUA (i.e. restricted airspace)?


texts: How to calculate Night Flight time for a given flight?

texts:
I am currently working on a project (web app) at university to be able to calculate the amount of time spent during night flying. Currently, I have,  Departure Lat and Long and Departure Time in UTC  Arrival Lat and Long and Arrival Time in UTC Sunset and  Sunrise Times (Based on dates) for both Arrival and Departure airfields in UTC
An example:  Depart UK Edingburgh airport on the 23 April 2019 at 11:10 UTC  Arrive Riyadh Airport at 18:10 UTC Total Time 7hr  day flight = ?  night flight = ?
I know many places online do this type of calculation for you, so I am wondering if there is a formula or method available that allows me to do this calculation (Which I can then convert to code)?
Thanks


texts: How many executive jets does the US military have access to (as opposed to owning outright)?

texts:
Last night around 8pm at least 12-15 executive jets flew into PSM over my house one after the other. Apparently the Air Force brass were having some kind of powow, which isn't surprising given that the new refueling tanker has just been deployed to Pease so they are probably having a lot of reviews and evaluations.

However, after jets kept flying in I started thinking how many of those things do they have? According to the Wikipedia, the Air Force only has 18 (rather antiquated) C21As, which I find hard to believe, since if that is the case, the whole fleet flew into Pease last night. Also, I find it pretty hard to believe that they don't have newer jets.

I suspect that the reason why the true number of jets is not listed, is that the list only includes executive jets that the Air Force owns, and does not include those that it leases. Are there any easily available statistics on aircraft leases by the Air Force?


texts: If planes can go faster, why don't airlines fly faster?

texts:
I came across this page where a DC-8 set a record in 1964 for a 12h24m flight from Montreal to Tokyo. Last year I flew to Tokyo from Montreal and it took 9h from Vancouver (where I had a layover)

I suspect the answer is along the lines of "for safety reasons", but surely in the 5 decades since that record airplane design and safety protocols have improved such that today's planes can fly faster and safer.

Am I mistaken in that airlines today don't fly at the fastest the airplanes can ? If so why not ?


texts: What is Full Fuel load and how does it differ from Fuel Capacity?

texts:
I've noticed that the fuel capacity is much higher than the full fuel load. For example in a Cessna citation 560XL
The Fuel Capacity is 6740 lbs
The Payload W/Full Fuel load is 960 lbs
Why is there such a difference?


texts:
I can't say anything about authenticity, but here is a quote

Tower: “Delta Zulu Romeo, turn right now and report your heading.”
Pilot: “Wilco. 341, 342, 343, 344, 345…”

Is such an instruction even allowed? And if so, what should the pilot's response be?


texts: Why did the speed of this plane drop so much?

texts:
(Disclaimer: I know nothing about aviation. It is not even a hobby to me. I'm sorry if this question sounds obvious or silly to experts.)

I was casually checking the arrival time of a flight on FightAware when I came across this strange speed profile, apparently for a routine flight between Korea and Japan:

(Reference: https://ja.flightaware.com/live/flight/AAR152/history/20171009/0035Z/RKSI/RJSS)

Indeed, it seems that the speed of the plane went slowly down, in a controlled way, and reached 380 km/h for about 5 minutes. Then it went up again, much faster, and came back to its normal value. The event had no influence on altitude.

As I said, I am no aviation expert, but... 380 km/h at 10,000 m seems SO SLOW to me! The speed was more than divided by 2 and actually came close to the speed of a train. To my knowledge, I’ve never been on a flight that slowed down so much in mid-air (and it would freak me out).

I then checked many other speed profiles to see if it was a common pattern, but I couldn’t find anything close to this. How could one explain such a steep decrease in speed? Is it a common occurrence or a rare safety issue? What usually causes this kind of event?


texts: Can multiple airfields be in the same airspace?

texts:
After reading this answer that a restricted airport caused a strange cutout in Class B, I am wondering if it possible that there are multiple airfields in the same airspace?

If yes, then:

Which ATC has most authority
How congestion is handled?

Please note that I am not talking about an airport which is under an outer circular shelf of a Class B or C airport.


texts: How much impact can be taken when flying in formation?

texts:
This recently published 360-degree video shows four F/A-18 Hornets performing impressive maneuvers what appears to be only a few inches apart.

Considering the risk of impact I find it hard to believe that a very slight contact would lead to immediate disaster.

Is this true? Assuming no damage is caused to the aircraft, how much impact can be handled (somewhat) safely?


texts: FAA SID charts show the top altitude, the maximum altitude you can climb to when cleared for the SID. Do Jeppesen SID charts also show the top altitude? I checked some of them but couldn't find it. If Jeppesen charts do not show it, how do you know the maximum altitude for SIDs?


texts:
I've always thought they are empirically derived: once you have your axial compressor phisically in a bench, you set both a rotational speed and a mass flow throught the turbomachine then you measure the pressure ratio so you can fix a point on the map. After, It will be made for several mass flows therefore defining a particular constant speed line.

It is correct?

(image source: Wikimedia)


texts: What's going on with sudden acceleration/deceleration in mid-air?

texts: I was recently on a flight between LGB and PHX. I've been flying since I was 5, am now 31. After takeoff, as the plane approached cruising altitude, the plane slowed down. A lot. Then accelerated again, followed by another slowing down. This happened at least 4-5 times during the short flight, and before landing we made a complete circle around the airport, I'm assuming to comply with which runway to land on. My question is: why, or what cause, does a plane slow down in mid flight where you move forward in your seat, like hitting the brakes in your car too hard multiple times. I understand training and all that, I want to know the cause. To put it in perspective, I assumed the engines stopped. And to increase the nausea, we were delayed by a mechanical issue for an hour.


texts: Was the P-82 twin Mustang better than the P-51D?

texts: The P-82 twin Mustang was made to replace the P-51D in the escort role. It was faster, and had two engines with two pilots. It also had a better armament but wasn't as maneuverable as the P-51D. Which would usually win in a dogfight and what plane did pilots prefer?


texts:
I had posted the question below on a New York Times article, but did not get any useful replies.

The series of six successful Inmarsat pings known to exist, MAY carry enough information to say if the plane most likely went along the S or the N arc we see in reports. Unfortunately, only the last ping (at 8:11AM) is available publicly.

Here is the basic idea on extracting the information: A Malaysian military satellite gave the last geographic fix of ML370 at 2:15AM. A circle can be drawn with this point as the center and distance traveled at maximum speed as diameter, confining the plane's position at 3:11AM. From the ping at 3:11AM, another circle can be drawn, like the one drawn at 8:11AM. The intersection of the two circles give an arc of most likely 3:11 AM positions.
At 4:11AM, we will have a series of circles from max distance and one circle from the ping. These intersections will give a series of possible arcs.

This process can be repeated (with increasing complexity, of course) giving us a series of most likely positions at 3:11AM, 4:11AM, 5:11AM, etc. If the trajectory of these sequence of spaces has a N/S directionality, we can say with some confidence that the aircraft went that way.

In reality, this would be more complicated. For example, the plane most probably did not go along a straight path at max speed. However, useful inferences can be made by adding other information available. For example, from the ping circles separated by one hour, we can get plausible directions the plane may have taken. Why isn't anyone pursuing this line of analysis?

There is a bit more detail here. Anyone estimating possible paths of MH370 quantitatively?


texts: Where could I find a MATLAB implementation of TCAS algorithms?

texts:
Where could I find a MATLAB implementation of TCAS algorithms and simulation?

My research work deals with collision avoidance of a multi-UAV scenario in a small airspace.


texts: Which FAA certifications may be used as a name suffix and how are they properly used?

texts: You often see pilots using some of their certifications as name suffixes. eg. John Smith, CFI or John Smith, ATP CFII. The Wikipedia page for ATP mentions that the ATP may be used as a name suffix but provides no reference. Does anyone know which certifications may be used as a name suffix and how they are properly used?


texts:
While reading over the recent FDC NOTAMs, I saw this interesting entry come up:
!FDC 0/6362 ZOA AIRSPACE SPECIAL NOTICE..THE FLT INFO SERVICES BCST
(FIS-B) SERVICE FOR OAKLAND /ZOA/ ARTCC AIRSPACE IS REDUCING ITS FIS-B
PRODUCT LOOKAHEAD RANGE TO 5NM FOR THE SPECIAL USE AIRSPACE (SUA
STATUS) PRODUCT. SUA STATUS INFO CONTINUES TO BE PROVIDED VIA THE
FIS-B NOTAM PRODUCT. ALL FIS-B PRODUCT FORMATS REMAIN UNCHANGED. THIS
UPDATE WILL OCCUR BTN 1400-1600 ON JUNE 11 2020. ANY OBSERVED ISSUES
SHOULD BE REPORTED VIA EMAIL TO [REDACTED] 2006111400-2008111600

Am I understanding this correctly to mean that SUA status sent over FIS-B will only cover a 5nm "hockey puck" around the aircraft?
That seems incredibly small, to the point where the data seems useless now — you'd have to be practically on top of a piece of special-use airspace before you'd get any information about it.
Does anyone the background behind this change is and what the actual impact is?


texts: Do pilots know which heading to fly in case of a go around?

texts: If the choice to go around is always an option for the pilot as described in Do pilots need a clearance to go around?, is the heading to go around always well-known at every airport?


texts: Why does the A340 have 4 engines instead of 2?

texts:
I have noticed for a while the A340 has four engines and the Boeing 777 only has two engines and they are about the same size. So why can't an A340 have two engines instead of four?

A340

. B777

On a jumbo jet like the B747-8 four engines are a requirement.


texts: Do the stabilators on the F/A-18 also have a roll function similar to the F-22?

texts: I'm curious about the F/A-18C. I know it has ailerons, but they seem too small to be greatly effective at low speeds. Do the stabilators have a roll function as well? If so, is there a speed at which one or the other becomes inactive?


texts: Which came to be first - bigger airplanes, or longer runways?

texts:
I'm generally speaking about airports with runways long enough for airliners, be historic or still in use. In order not to turn this question to a chicken-egg discussion, here are my points:

Would making an airport(s) before making the actual airplanes be
feasible and cost-efficient ?
Will new(and more runway-length
demanding) airplanes be able to take-off from shorter runways,
because there are no other options ?

I'm generally interested in historic terms, which came to be first - bigger airplanes, or longer runways ?


texts: How is the pitot/static system of a helicopter affected by rotor downwash?

texts: Since the fuselage of a helicopter is affected by downwash from the rotors, how is the pitot static system affected?


texts: Why does the F-22's wing give it such great maneuverability?

texts:
An F-22's wing is much different than a wing like the one on the F-16.

This an F-16 wing design:

(Source: www.aviastar.org).

This is an F-22 wing:

(Source: s3.zetaboards.com)

There is a great difference between the 2 wing designs. The F-22 is a very maneuverable aircraft and can out perform almost all the current fighter jets. The YF-23 has a very similar wing design and is considered to be one of the most maneuverable aircraft of all time.

So why does this wing design give the F-22 and YF-23 such good maneuverability?

The YF-23:

(Source: en.wikipedia.org)


texts: Approximately, how fast would an aircraft have to travel through freezing air to melt the ice off the wing, propellers, or rotor blades?


texts: If an aircraft decompresses at altitude will everyone start farting?

texts:
From what I understand about how gases and liquids work, if the environment loses pressure, then it causes dissolved gases to come out of solution. For example, if a diver ascends too quickly, dissolved nitrogen will come out of solution causing the "bends".

I have heard that astronauts undergoing decompression training experience gastrointestinal distress from the effect.

Does this mean that if an aircraft at altitude suddenly decompresses that everybody will start farting?


texts:
The answers to this this question make it clear how modern airliners dump fuel in the case of an emergency. As far as I understand, fuel dumping might be done to lower an aircraft's weight to the maximum landing weight, particularly soon after takeoff.

As far as I understand, jet fuel is typically not safe. When I, as a complete outsider, hear of fuel dumping, I imagine a whole bunch of dangerous corrosive fuel being dropped on whatever happens to be below, and it sounds like a frankly awful idea.

What makes fuel dumping safe, or if it is dangerous what makes it worth it?


texts: Are there planes that can fly without wings? How would a plane be able to fly without wings?

texts: Are there any planes that can fly without wings? How do they produce lift? How do they control the attitude?


texts: What is the axis of rotation in a high alpha roll?

texts:
When doing an aileron roll at a high alpha (say 25 degs), which axis will the aircraft rotate about?

Is it the incoming air-stream vector or is it more the body X axis? And does the pitch inertial coupling factor into this or is that an unrelated phenomenon?

I am thinking in terms of high agility aircraft like for example the F-16.


texts: What are the essential elements of a control tower?

texts: Assuming control towers are essential for large airport operation, what is the minimum needed equipment inside the standard control tower to support airport operation?


texts: On the ICAO Flight Plan Form, does /S replace O, V, and L?

texts:
I know the S stands for standard equipment (VOR, ILS, VHF radio).

Is the format like G/S (GPS with standard equipment), or does the /S not imply coverage of the other line items, i.e., VLGO/S?


texts: How does the runway number relates to Magnetic Heding/Course?

texts:
I know that runway numbers correspond to Magnetic North, how does it relate to Magnetic Course/heading?

Can we say that the runway number is equivalent to Magnetic heading?


texts: What is the usual range of Approach and En Route ATC VHF radios?

texts: I was wondering what is the regular range of Approach VHF radios used by ATC (normally 50W)? And what about En Route VHF radios (usually 100 or 250W)?


texts: How did lateral and longitudinal separation minima evolve?

texts: What is the evolution in time of lateral and longitudinal separation minima?


texts: I've been watching YouTube videos and when they're going through the checklist they say "packs off" can anyone elaborate?


texts: How to calculate on ground aircraft yaw rate knowing the longitudinal speed and inferred yaw angle

texts:
Please consider the following scenario:

a generic aircraft is on-ground taxing at 50 feet per second (~15.25 m/s, ~29.5 knots)
The pilot inferred 20 degrees of yaw

How can I calculate the yaw rate of the aircraft? Do I have enough information to calculate it?


texts: What backup systems are in place for flaps actuated by sliding block guides?

texts: Looking at this video of a 737's flap extension, it looks like there is just one screw per side driving all of the flaps. Are there any systems in place that will allow the flaps to extend in the event of the linkage failing? What if hydraulics are lost? Also see point 3 on this question for more information about the flap type I am asking about (but generalized answers are welcome).


texts: What is the width of a high altitude airway?

texts:
Victor airways (airways that are below 18,000 ft) has a width of 8 NM. How about those airways that operates higher than 18,000 ft, do they have specific width you must be in?

Or is there no width because you would be using GPS? (ones with an RNP of 2 NM)


texts: Please explain real-world procedures behind this "ATC joke"

texts:
One of the well-known kind of the "ATC jokes" (funny excerpts from real or invented communication between pilots and air traffic controllers) has recently caught my eye.

I can't seem to understand what actual procedures or rules does it refer (or allude) to:

  Pilot: "Approach, Federated 303's with at 8000' for vectors ILS, full stop.

  Approach: "Unable Federated 303. The ILS is out of service."

  Pilot: "We'll take the VOR then."

  Approach: "Sir, the VOR's in alarm right now. Standby."

  Pilot: "OK, guess it'll have to be the ADF then."

  Approach: "303, unable the ADF right now for traffic saturation."

  Pilot: "OK, approach. State my intentions."

(src)

Could you please enlighten me on what does the last (highlighted) line is intended to mean and/or convey? I understand it's a word play on "state your intentions", but what exactly is it supposed to mean?


texts: Why did the FAA ban all supersonic flights over the United States, rather than only supersonic flight in densely-populated areas?

texts:
A major part of why the Concorde was far less of a hit than predicted, and of why the many 1980s and 1990s supersonic transport projects never got off the drawing board, was that the FAA had banned all commercial supersonic flights over the United States in 1973 (two years after the original U.S. SST effort collapsed) due to concern over sonic booms, locking SSTs out of the lucrative U.S. transcontinental routes.

Given that transcontinental supersonic flights could have been flown with minimal disruption on the ground by routing them mainly over sparsely-populated areas and using brief periods of subsonic flight over major population centers (here is a map of some possible routes), why did the FAA impose a blanket ban on commercial supersonic flights, rather than merely banning supersonic flights over or near densely-populated areas?


texts: I live directly south in the line of a north-south landing strip of a low-traffic airport. What should I know?

texts:
There is an airport in my city that is relatively low traffic. It has a landing strip that runs north-south, and it looks like if you were to go ten miles straight south from that landing strip, you'd pass over my property.

The noise is infrequent and quiet enough that it isn't very bothersome, but I'm more or less in the flight path. But I'm ten miles away in its airpath. What should I be concerned about?

Should I be concerned about jet fuel exhaust or anything as far as my personal health and safety are concerned?
Is there any precaution I should take in the event that aircraft were to fall into my property?

What else should I know?


texts: Are there any operational, combat capable multicopter drones (as of 2019)?

texts:
Are there any small operational military drones with any form of weapons system on board, as of 2019?

I'm basically referring to a more powerful, more sophisticated and refined version of something similar to this:


texts:
The other day I was spotting at Miami International (MIA/KMIA) and noticed something hanging out of the fuselage.

A man with a green jacket is holding a device attached to a cable. Can somebody determine what that is?


texts: I've heard the term "frozen ATPL" and it seems to be some kind of limited EASA ATP certificate. What exactly is a frozen ATPL? What privileges does it give the holder? How is it unfrozen to become - presumably - a regular ATPL?


texts: What is a GDS (in the context of the airline industry)?

texts:
I have been looking at this article and throughout the article they mention GDS's but do not explain the terminology. Does somebody know what they are talking about -

For e.g. -

  Three GDSs emerge from the previous CRSs and sold off by airlines;
  pricing transparency grows - centerforaviation.com

CRS I am assuming/presumng means Computer Reservation System.


texts: Do aircraft carry commercial VHF radios?

texts: Years ago, I was working in the bush and we used portable radios on something like 154MHz. When it came time for pickup, we were able to talk to the helicopter pilot on that frequency. Since it's outside the air band, I'm wondering if it's normal for aircraft to have VHF radios installed to cover commercial (and maybe amateur) VHF bands.


texts: What protects the location beacon (pinger) of a flight data recorder?

texts:
The pictures of flight data recorders show that the location beacon (pinger) is outside the main protection encasement:

Is it really a good idea to keep such a vital instrument unprotected? Or is that round metallic thing strong enough to resist impact and fire?


texts: Is there any automated go-around procedure?

texts:
In Wikipedia's description of one of air crashes (probably Thai Airlines, if I recall correctly), I found a remark saying something like that: "Crew decided to go around, but apparently decided to undertake this procedure manually".

I'm surprised. "Apparently"? Making go around manually is something odd? Do we have any automated (autopilot-based) go around procedures or techniques in common use? I was always more than sure, that procedures like go around or touch-and-go are always made manually by a pilots.


texts: Why do many stealth aircraft have a similar shape and design?

texts:
I have been playing around on a bunch of programs with stealth planes and their general shape. I know that they are required to be flat and have some sort of special material/paint on to 'absorb' the radio waves.

But I have been pondering about the required shape of these aircraft and why the flying wing shape is so widely used (excluding its lift efficiency). Why not some other shape, like a tilted square, triangle, or even a sphere? What makes the general shape of the B-2 and F-117 so common in the design of stealth aircraft?


texts: Can you recommend IFR material for Europe?

texts: Is there a European equivalent to the FAA's "Instrument Flying Handbook" and "Instrument Procedures Handbook" that will illustrate how to fly different procedures in accordance with ICAO PANS-OPS Doc 8168 and read approach plates (Jeppesen), etc.?


texts: What type is this aircraft and engine at Munich airport?

texts: Please help me to identify the plane and engine.


texts: How quickly should heading changes be accomplished?

texts:
While airborne if there needs a change in heading, then what is the rate of change of heading with respect to time?

Like, I want to change my heading from x degrees to y degrees, where the difference is 45 degrees, do we have some specific time limit in which we have to get this change and do we have some regulation/standard for specific rate of heading change?


texts: When is turbulence most dangerous to an aircraft?

texts: In what general situations or flight scenarios is turbulence most dangerous to aircraft? When could it be bad enough to bring down an aircraft (even up to something as big as an A380)?


texts: How does ATC radar display differ from military radar?

texts:
Could you summarize what sort of data/objects are present in one type of display but not another? (not asking about construction differences, just the user-facing end, the display/interface.)

A somewhat related question "What data is displayed on civilian ATC radar screens?" shows example ATC displays. What of these would military radars miss (like obviously unknown data about enemy aircraft) and what extra would they present? Also - what sort of objects would appear on one but not another (in particular: non-aircraft; I heard for example flocks of birds sometimes appear on the radar, but never what kind of radar.)


texts: Lights at the end of both wings of any airplane

texts:
Can anyone please explain to me why there is one green light at the end of wing and on the other side there is red light? what is the purpose of it and why it uses different colors like red and green instead of same color light?

The question is not about the position of the lights but why they use different color lights? like red light on the left side and green light on the right side. Is there any specific reason for that?


texts: Did the X-15 ever conduct a point-to-point flight?

texts: The North American X-15 rocketplane flew at up to Mach 7 and at very high altitudes, it was also capable of spaceflight but these were quite steep parabolic patterns. At Mach 7 it flew leveled and my question is whether the X-15 ever landed on another airport than the one it launched from (attached to its B-52 carrier plane so actually the airport where the B-52 launched from). Wikipedia seems to be silent on this.


texts: What is the difference between the FAA FNS NOTAM and the FAA PilotWeb NOTAM websites?

texts:
I figured out there are currently 2 different FAA websites for NOTAM online search:

FAA FNS NOTAM website available at https://notams.aim.faa.gov/
FAA PilotWeb NOTAM website available at https://pilotweb.nas.faa.gov/

What is the difference of each one? Which one is better to use? Do both of them provide information about Distant (D) NOTAMs, Local (L) NOTAMs and FDC NOTAMs?


texts: What is the quickest way to get an airship rating?

texts: I already have private pilot for single engine land with instrument and commercial ratings.


texts: Could a rear center of gravity position cause an airliner to lose control when a pitch-up is commanded?

texts:
Modern aircraft cruise with the center of gravity close to the most rearward position to minimise trim drag, usually achieved with fuel in the tail surfaces. This is transferred forward before or during descent for landing.

Is it feasible that unexpected nose-up inputs could lead to partial stall with the aerodynamic center moving rearward, aggravating the nose high attitude to cause mushing? This is my suggestion that might explain the loss of AF447.

Without ASI (pitot icing) a pilot without experience of this might not recognise the problem. Further, in that attitude elevators could be ineffective and fuel transfer too slow for recovery that way.

This was a serious problem with T-tails and caused accidents to DC9, Trident, BAC1-11 and Tomahawk aircraft; maybe others.

The only solutions were stall warning and stick pusher systems, apart from streaming the braking 'chute by an RAF Victor crew.


texts: How do you calculate trip fuel based on hourly fuel burn rates?

texts:
I am working on a small personal project that uses fuel burn data about specific aircraft to calculate the total fuel required for a trip. The data looks like this:

          | 120000 kg  | 150000 kg | 180000kg
----------+------------+-----------+-----------
21,000 ft | 6250 kg/hr | 6350 kg/hr| 6450 kg/hr
22,000 ft | 6225 kg/hr | 6325 kg/hr| 6425 kg/hr
23,000 ft | 6200 kg/hr | 6300 kg/hr| 6400 kg/hr

Based on the table above, you can see that to cruise at 21,000 ft and a weight of 120,000 kg, you would burn 6250kg/hr.

The problem I am having is that in order to calculate total weight, you first need to know total fuel, which you don't have until you know the proper burn rate. What would be the proper way to calculate fuel based on this information?


texts:
Can anyone identify this aeroplane?

Location is Cordoba, Argentina.


texts: It is possible to feel a difference between helicopters with clockwise direction rotor and counterclockwise rotor?

texts:
From the perspective of a pilot, is there a difference when flying a helicopter with a clockwise turning main rotor vs a counter clockwise turning main rotor?

Would a pilot notice if they flew the exact same helicopter except with an opposite rotation (and obviously all the corresponding mechanics mirrored.)


texts: When are multiple hops more efficient than single leg?

texts:
Considering a very long route (equal to the max ferry range of an aircraft[1]).

Would it be more fuel efficient to fly multiple legs or a single one ?

Multiple legs would allow you to use less fuel, decreasing weight and fuel consumption
Single leg would dispense you having to go through multiples takeoffs and time increased at low, high drag altitude

How does theses balance ?

I'm interested into any real world aircraft[!].

[1]: Results might differ for each models so you can pick any you like.


texts: Since jet fuel is cheaper, why do pistons still use av-gas? Why is 100LL used at all?


texts: Under what conditions do I need to have a takeoff alternate airport listed on a dispatch release?  How far away can my takeoff alternate airport be?  Do I need to worry about this in part 91 operations or is it just a 121/135 thing?


texts: How do you know the maximum load a control surface can withstand?

texts:
source

This is a separate strength testing (load testing) of the elevator of an airplane, how was the load determined? How did the engineers determine the maximum elevator load?


texts: Why is radar required on some FAA instrument approaches?

texts: The ILS / LOC approach at KCXY states radar is required. I understand I can't fly the approach if not in radar contact. However, if flying the LOC approach I think I can identify both final and HORVI (for lower minimums) using HAR VOR. There's no reason I'd need the controller to call out a fix. If that is true, why is radar required? I think it would be more of a safety concern because of terrain and an adjacent airport (HAR Int)?


texts: Concorde thrust reversers engaged on parked aircraft, but not all engines?

texts: Am I correct in interpreting this photo as showing one thrust reverser engaged, while the other is open? Do the thrust reversers fall into place on a fully powered down Concorde? Could this be caused by an engine being removed for display? If so which engine was removed?


texts: Do instrument approach procedures sometimes have a minimum temperature?

texts:
Non-precision instrument approaches generally have altitude restrictions which get lower when you get closer to the airport. I always figured these restrictions were AMSL using the current altimeter setting, not compensating for temperature.

Some have heard the mnemonic that mountains are higher come wintertime, which basically means that colder weather make your altimeter read higher than you actually are (or, as most pilots prefer to think, you're lower than what your altimeter reads)

Have a look at this VOR approach into Newark

Most altitude restrictions are a minimum level, so you're free to fly higher if it's a particularly cold day. But have a look at LOCKI intersection, the final approach fix. That's at 1500 ft, not at-or-above. At -40, this will put you around 1100 ft above ground level. Although I don't see any obstructions that high during this segment of the approach, as far as I know instrument approaches are supposed to guarantee a 500 ft obstacle clearance, do procedures using this kind of restrictions have a minimum temperature?


texts: What is the Relation between Critical AoA with Chordline?

texts:
I read here an explanation about angle of attack (AoA) as below:
Overly long (forward-back wise) wings will generally have a smaller critical Angle of Attack while smaller ones will have more tolerance before stalling since Airflow starts to become turbulent in form of eddy currents.

I never heard that claim before neither I ever read. I have searched in this forum if someone asked that question previously, but seem is not. I could not find. Is anyone have reference to this claim?


texts: How to calculate the fuselage geometrical parameters?

texts: How I can calculate the fuselage midsection having a constraint length? Also, if I want a cross section shaped like an Antonov that on top of it have a lower ratio than the bottom, as that is part or can do the calculations to determine the area in front.


texts: Light indication of a 2-bar system while on the correct glideslope?

texts:
I am trying to compare a VASI-4 light system with a PAPI lights. I know that 2White-2Red is the pattern that indicates that the aircraft is on the glideslope; more reds mean lower and more white means higher than the desired glideslope height. With relations to that, how should the VASI lights be on a correct/incorrect approach?

P.S. My question is specific to VASI-4 light system aka 2-bar VASI.

UPDATE I found this from FAA that may very well be the answer, but an explanation would be great.


texts: Our company pilot lost the aircraft logbook for about 15 years worth of flights.  Boxes of stuff.  Who knows how he lost it.  We now want to sell the aircraft - can FAA reconstruct the logbooks?  If costs are involved can we get the pilot to pay for it?


texts: The Nemesis Formula 1 racer is a small plane 1991 to 2000 champion setting a lot of speed records.  It went over 260mph, it was fast for its size and engine.  Its fast wing helped it fly fast.  How exactly does its wings fly so fast and smooth?


texts: What general aviation operators might hire a low time pilot?

texts:
I recently obtained my CPL at FTA.
In one of the answers:

The normal progression is this - you can technically get a flying job after 150-200 hours of private training and flying, having achieved your commercial pilot licence (CPL). I say 'technically' because if you only have minimum hours and minimum qualifications you have to look very hard for a job. Most people straight away get an instructor rating, so they can get a job teaching people to fly. Other early jobs include sightseeing flights, parachute flights, and mail flights to remote towns.
Your training will have been in light aircraft, but fortunately Australia has possibly the largest light aircraft industry in the world, so there's lots of jobs in these planes. It's highly unlikely that your first job will be in anything bigger than a 6 seater plane.

Could somebody suggest based on your experience, light aircraft operators willing to hire a 250 hours pilot?
I already sent my resume to a list of GA operators and did not receive any reply. I need some advice on the best approach when trying to get my first job.
Look forward to hearing from you.


texts: Has Air Traffic Control ever had to talk a first time pilot through a landing due to an emergency?

texts:
This question deals with the plausibility of the Hollywood cliché of a passenger on a commercial jetliner landing a passenger plane.

My question is related but broader, and less hypothetical:

Has anyone ever found themselves in an emergency with no piloting experience (e.g., the amateur pilot of a small plane dies or is incapacitated, and the only other person in the plane has never flown anything before) and been talked down by Air Traffic Control?


texts: Why are SBAS-equipped planes exempt from the preflight prediction check?

texts:
My question stems from this other question: Why is training regarding the loss of RAIM given so much more emphasis than training regarding the loss of SBAS?
Two answers say losing RAIM puts a question mark on the integrity of the GPS position. And losing SBAS only affects LPV approaches.
Yet from this other question, Why weren't SA-On GPS units updated to become SA-Aware?
According to Advisory Circular (AC) 90.114A CHG1, now and past 2024, SBAS-equipped planes do not need to do a preflight prediction check.
Why skip the important RAIM prediction step?

RAIM = Receiver autonomous integrity monitoring
SBAS = Satellite-based Augmentation System
LPV = Localizer performance with vertical guidance


texts: Can heated air be provided in the cabin in commercial airlines?

texts:
Having travelled quite a number of times, there are times, when the cabin becomes a bit too cold, or people with certain condition get shivering quickly. In such circumstances and generally, is it possible to request for heated air in the cabin. If not the entire cabin, but atleast to specified seats, via the air flow controller on top of the head.

Before that, are airlines equipped to provide heated air, like in a car?


texts: What are some common factors that affect GA aircraft manufacturability?

texts: Recently, we've seen Icon go through layoffs due to production delays related to "Manufacturability". I assume this is due to their wing structure in part, but I'm curious, in general, how a company goes about designing with manufacturability in mind.


texts: How does retracting flaps help extend the glide of an aircraft?

texts:
As per the video from Smithsonian channel

BA flight 38's captain retracted the flaps of the Boeing 777 by 5 degrees to extend glide, to travel further.  Why?


texts: On the 737 MAX, can the pilots switch to the backup MCAS, or switch active MCAS input to another AoA probe during flight?

texts:
According to this article, my assumptions about the Boeing 737 MAX flight control system are (please correct me if I am wrong):

The aircraft has two flight control computers (FCC)
The aircraft has two angle of attack (AoA) probes
The Maneuvering Characteristics Augmentation System (MCAS) is implemented as a function of each FCC
Data from the port AoA probe is supplied only to FCC 1
Data from the starboard AoA probe is supplied only to FCC 2
Only one FCC (FCC 1 or FCC 2) is active during each flight, with the other serving as a backup system

Assuming a situation where only the AoA probe used by the active FCC produced incorrect AoA information and thereby causes the MCAS to intervene while the other AoA probe is functioning correctly, would it be possible to either

switch to the other FCC (which uses input data from the other AoA probe)

or

switch the active FCC to use input data from the other AoA probe

and thereby prevent the MCAS from continuing to use incorrect AoA data?


texts: How can I check pitot static leak without a test box?

texts:
More than once on the ramp, I've wished I could check an aeroplane's pitot-static system for leaks, but I didn't have the test box.  I've since seen, in the FAA's handbook for checking  homebuilts, a way of gently pressurizing a pitot system which is great - a length of medical tubing is all you need.

Does anyone know if a similarly simply elegant arrangement exists for the static system?  I've tried a largish hypodermic syringe to check if the port was blocked, but the challenges are:

getting to sit tight on the static port, and
holding suction.

All suggestions welcome.


texts: Why did Lockheed abandon the Constellation II?

texts:
It’s well known that Lockheed never designed a first-generation jetliner.

Not as well known: they actually did!

The L-193 Constellation II, a quadjet with four tail-mounted engines (a configuration Lockheed would later reuse for their Jetstar business jet, and which was otherwise seen only on the VC10 and Il-62), was designed in both an airliner and a tanker version, and it actually won the U.S. Air Force’s 1955 jet tanker competition, beating out Boeing’s KC-135.  However, since the Constellation II was still a couple years away from flying, the Air Force bought a few KC-135s for use in the meantime, soon decided that they were good enough for the purpose, and eventually cancelled the Lockheed order.

At which point Lockheed abandoned the Constellation II entirely.

Which is odd, because Douglas, in pretty much the same situation at about the same time, didn’t abandon the DC-8 when the prospect for a tanker version thereof vanished in the KC-135’s jet blast; they merely redoubled their efforts with the DC-8 airliner, and went on to great success in the marketplace.  Lockheed, on the other hand, gave up on their jetliner when they lost the Air Force tanker contract.  Why?


texts: Why do jet engines sometimes spit out flames after ingesting birds?

texts:
After seeing this video of a 757's engine catching fire because of a bird,
I wonder:

What happens to the engine?
Why does it periodically exhaust fire?
Is this some safety feature?


texts: Why are the engines not tucked underneath the wings of airliners?

texts:
If you look at the engines of an A350 and other similar aircraft, you will see that their engines stick out ahead of the wing. Why? Why aren't they tucked under the wing?

(Source: Airbus)


texts: Why is the shape of the cargo compartment similar in large aircraft?

texts:
Why are the lower deck areas shaped like that, does that save some space? I find it common across lot of big aircraft.

Pic of a 777:


texts: How does the V-22 Osprey share engine power between its rotors?

texts: I learned through a comment on this question about multiple engines powering a single propeller that the V-22 Osprey can power both rotors from a single engine, or use both engines to power a single rotor. What are the mechanical systems that make this possible?


texts: Why were the specifications of the Pipistrel Panthera downgraded?

texts:
I'm curious if this was a failure of the simulations or a result of the engine swap they did at the last moment. Originally, they said they could cruise at 200kts @ 10g/h fully loaded. Now its down to 155kts.

http://www.panthera-aircraft.com/technical-data

EDIT:
Just wanted to add, for reference, a page which gave their original estimates.
http://www.pipistrel-usa.com/models/panthera.html

You will also notice at the top of the page for the first link where they reference the 200kts with 4 people for 1000nm.


texts: Who is the third pilot in this Qantas Airbus 380 long haul flight?

texts:
In the documentary, Secret Life of the Long Haul Flight (2017), we get a look at a long haul Qantas flight from London to Sydney.

One of the scenes shows the flight deck with three pilots (at least their epaulettes have chevrons on them). What is the third pilot in the middle doing? Just hanging out? If he's on rest, shouldn't he be in the rest quarters and not on deck?


texts:
For the purposes of regulations how do the FARS define daytime? Is it sunrise to sunset, civil twilight, astronomical twilight?

This question was asked before with regards to EASA rules, but FAA was not included.


texts: Slotted wing loading and structural analysis

texts:
I'm trying to determine moments and forces on a wing with a fixed leading edge slot (trying to verify the Ragwing RW19 wing before starting the project). It's quite straightforward for a non-slotted wing, but when working with slots, I've run into several problems I don't know how to solve.

How do I determine the Cl and Cm of such wing? The XFOIL simulator is not able to work with two element profile AFAIK.
Should I calculate the wing loading for non-slotted wing only or should I also add the area of the slot?
Where is the aerodynamic center of the slotted profile? Is it around quarter chord (approximately) from the leading edge of the non-slotted wing or is it measured from the leading edge of the slot?


texts: What is the ATC phraseology to request a parallel track?

texts:
What is the correct phraseology to request a parallel track due to weather for example?

Something like:

  OE-DLM, request parallel track to the east, 2 nm

Background: I am asking for non-airline operations under IFR. I am using the GTN 750  and there is a feature to easily create a parallel track with a specified distance to the original route and I would like to use this feature. For example, when I'm in cruise flight, I see a weather cell and want to fly next to it by offsetting my route.


texts: How to calculate the moment/torque at the center axis of a blade?

texts: How do I calculate the moment/torque at the center axis (same plane with lift and drag force) of a blade with NACA airfoil standard when it is placed inside a wind tunnel or exposed to airflow?


texts: How to literally take the wing off a single engine Beechcraft-style airplane?

texts: First off I do not want to do any kind of maintenance. I was driving past an auto junk yard and saw they have half of a low wing, maybe a Beechcraft, airplane and I would like to try and buy the wing for a table or some type of project. I would like to know what kind of tools required to do such a task other than a sawzall!


texts: Is there ground effect flying below an infinite 2D plane as opposed to above one?

texts:
People talk about wing tip vortices and say things like the ground acts as an aerodynamic mirror. What (if any) difference would there be for a wing flying underneath a 2D plane? As in the picture below:

The uppermost plane is flying at an altitude well outside ground effect. The middle one is flying in ground effect, and the bottom one in the hypothetical situation with a plane on top of the plane (pun intended).
Source of the picture, edited to suit the question:
http://www.aerospaceweb.org/question/aerodynamics/q0130.shtml


texts:
The crescent wing design seen on the Victor bomber seems to have a great number of advantages...

the critical mach remains more constant along the span, so the formation of shock waves is more even and has less pitch trim changes at high speed
higher inboard sweep at the point where the wing is the thickest increases the overall critical mach and thereby improves transonic performance
the curvature (somewhat?) reduces spanwise flow, thereby lowering tip-stall effects at low speed
when such a stall does occur, it happens at a point closer to the MAC, so the magnitude of the pitch-up is lower
because of the geometry of the approach, some designs will have a natural flare built-in - this was a major positive benefit on the Victor, although not a design goal

So... with all of these advantages, why doesn't everyone use them? Is there some disadvantage that is not being mentioned?


texts: What model of plane is visible in this image?


texts: Why don't airplanes have smoking cabins?

texts:
Is there any airplane model that has a small lavatory-like cabin just for smoking? I have never seen any such planes and that made me wonder why this is?
It would not take much more room than a normal lavatory, make it much less likely that someone will smoke in the lavatory regardless of the ban and provide smokers a way to satisfy their need.
I will have to add that I am not a smoker, just a person with weird ideas/questions.

Related Questions:
• Are there any airlines that still allow smoking on-board flights
• Was smoking banned because of passenger safety or occupational safety?


texts: What alternative methods are there for controlling a plane when flight control surfaces have failed?

texts:
I saw a TV show once about Japan Airlines flight 123, in which the aft pressure bulkhead ruptured, disabling hydraulics and ripping off the vertical stabiliser. So the flight crashed after some time of flying with up-and-down oscillation.

Since then, I've also heard of two flights in which the aircraft lost control of flight control surfaces, but pilots guided their crippled plane into a landing using engine throttles only:

United Airlines flight 232
2003 Baghdad DHL attempted shootdown incident, in which a cargo plane in Iraq was hit on a wing by a missile

In principle, could such a method have been used in Japan Airlines flight 123?

In principle, would it be possible to control such a plane by use of cooperating passengers moving around in the cabin, e.g. by instruction of a pilot, to shift the weight balance of the aircraft?


texts:
Wikipedia lists the busiest city to city routes.  But for instance (nb: this is purely speculation), flights originating in Boston would transit through much of the same airspace to get to LA as a slightly shorter flight originating out of DC.

What are the busiest actual air routes (airways) (irrespective of origin/destination cities)?  Total aircraft count, as well as passenger- and cargo-based metrics appreciated.

Is there a breakdown of aircraft volume transiting between and within the 22 area control centers in the United States?

The best map I've found so far came from this joint publication comparing the US and EU in air traffic management, but this does not show traffic flow between areas:

As originally phrased, I realize such a graph could get very much "into the weeds".  I'm rephrasing the question to start high-level and then work down (if possible).

For example, a flight from Tucson to LA involves a handoff from ZAB to ZLA, such that a numerical representation (aka directed graph) might look like this:

        In
        ZLA ZAB
Out ZLA  X   X
    ZAB  1   X

Adding flights from Tucson to Phoenix (within the same ARTCC) and from LA to Tucson would result in this:

        In
        ZLA ZAB
Out ZLA  X  *1*
    ZAB  1  *1*

Ultimately, this matrix would be 22x22, but since not all ARTCCs can handoff to all others, many cells would be zero.


texts: How to locate the owner of a 5' styrofoam wing found in a field?

texts: I found a 4-5' styrofoam wing in eastern Montana in a field. It has what looks like a registration number on it. How can I trace that number to try to return it?


texts: Can computer imposed inputs be overridden on the Boeing 737-MAX?

texts:
During Lion Air Flight 610, a Boeing 737-MAX, it seems that the angle of attack sensors caused the software to believe the aircraft was stalling, thus initiating a nose-down pitch to recover from the (non-existent) stall.

I was under the impression that the difference between Airbus' fly-by-wire system and the Boeing types, is that Boeing aircraft can have their computer imposed inputs overridden (as discussed in my previous question).

So in the case of this flight, would pulling up have not recovered the flight, and if so, why not?


texts: If you are not being radar vectored to the FAF or on a “no PT” transition, are there any other circumstances where a procedure turn that is depicted on an approach chart is not required?


texts: Is rebooting the computer normal before/during flights?

texts:
On a recent flight the captain made an announcement at the gate that they need to reboot the computer as somethings aren't working, and rebooting usually solves the problem.

After posting this on twitter I got a replying saying that most planes have 3 computers and rebooting during flight is common.

What are the reasons for reboot? For me it sounds like a software/computer that isn't tested thoroughly instead.


texts: Is the FlightGear sim accurate in 2018, specifically Cessna 172 aircraft?

texts: So, I fly on FlightGear as I like the fact its free. But is it accurate enough to train to fly the real Cessna 172? Are there any better free flight sims? Please give your honest opinion and please try FlightGear before answering my question, I can't deal with people telling me their opinions when they have not tried FlightGear yet.


texts: How can an aircraft turn if the horizontal force component is zero?

texts:
Here is the simplest coordinated turn diagram

Picture from https://physics.stackexchange.com/questions/100169/pendulum-in-a-turning-airplane

Being:

$L$ = aerodynamic lift

$\tau$ = angle between vertical component and lift

$Fc$ = centrifugal "force"

In many books you can read that:

$L\cdot sin(\tau) = Fc = m \cdot (V^2)/R$
 where $R$ is the curvature radius.

Then, how can an aircraft turn if there is no net force? I mean, from Newton's second law we have that $F = m \cdot a$ and in this case centrifugal force compensates for lift component in the horizontal plane.