texts: Is the balacing of the fuel in the wings of an aircraft like A320 done automatically or does it have to be done manually by the pilot. If it is done manually does the pilot eyeball the balancing ?


texts: Why can a Pilatus PC-24 land on unpaved and short runways like no other business jet?

texts:
In 2013 Pilatus Aircraft unveiled their latest aircraft, the PC-24 light medium jet. On the website of Pilatus Aircraft they give several reasons why the PC-24 is better than any other business jet, the first two being

No other business jet can operate from runways as short as 2,690 feet (820 m).

No other business jet has been designed to operate from paved and even unpaved surfaces.

This sounds pretty impressive to me. But what’s different between a PC-24 and any other light medium jet on the market, which allows such short landing distances and the ability to touch down on unpaved runways?

Press picture from Pilatus Aircraft which shows the landing on an unpaved runway.


texts: What type of engine/motor is used in aircraft APU?

texts:
Is the APU a mini-jet engine, or some other type of motor? I know its purpose is to provide power when the engines are off, but what kind of motor/engine is used to generate the power?

I assume this differs from one type of aircraft to the other, but for the purposes of narrowing down the responses - I would like to know specifically about Boeing's APUs lets say on the 737NG.


texts: What types of attitude indicators are there?

texts:
Learning to fly in general aviation in the west since the mid 2000s I'm used to the common attitude indicators like this one.

I've also seen older ones that are black and white as well as many varieties of attitude indicator display arrangements in glass panels.

My question deals with other ways of displaying this information. I've heard pilots talk about how some eastern airplanes have very different ways of presenting pilots with attitude information. What approaches are out there? What do they look like and where are they found?


texts: How to find the distance if the points are above Earth's surface?

texts:
There is a lot of information online about how to find the distance between two points if both the points are on the surface of the earth. But no article mentions about how to find the distance if both the points are above earth surface. Haversine formula works only for the points that are on the earth surface. But what about points that are above earth surface?

Note: I think we should consider the curvature of the earth as well while computing the distance.


texts: Are commercial aircraft water tight by design?

texts: If its submerged in water, will water rush inside the cabin? For instances, if its standing in a flooded airport or landed on the water gently.


texts: What are the FAA requirements for when to use an airline call sign & flight number versus the aircraft registration number?

texts:
Is there any FAA guidance which specifies when a call sign & flight number or registration number must be used for Part 91 & 135 operations?

I am familiar with the guidance on how to obtain an ICAO call sign (and in fact work for a company who has one), but am unable to find anything which specifies when one must be used versus the other.

So basically, can commercial flights file under the registration number and can private flights (re-positioning flights, etc.) file under the company call sign?  I understand that this is backwards from "typical" use, but is it legal?


texts: Is there a best-practice method to work through a checklist?

texts:
I've noticed that there appear to be many ways to read of a checklist between aircraft types and operators. The task and work division confuse me:

In some cases it appears to be entirely managed by the Pilot Not Flying [PNF], while in some cases the Pilot Flying [PF] is involved.
For the latter case, the response from PF seems to be 'checked' some of the time while in others there is a verbal feedback on the state of that control.

I guess this is a question between Standard Operating Procedures, but is there a best-practice to reading off checklists that is suggested to be followed as suggested by EASA or the FAA for instance?

Extra Thing: It would be great if somebody could elaborate on how a checklist actually would be worked through in practice like the one below with who says and does what.


texts: Why does aviation use Zulu time instead of the local time?

texts:
When reading aviation literature, it's common to find references to Zulu Time.

What is Zulu Time?
Why does aviation use Zulu Time instead of the local time?


texts: Are ETOPS rated planes denoted by a placard or other indicator?

texts:
A recent AA flight to Hawaii was not ETOPS rated.
(alternate article)

Apparently the failures that led to this mistake occurred on multiple levels, including the schedulers who scheduled this equipment, and the dispatcher who may have prepped the flight plan.

My question is if the crew had a means and responsibility to know if the plane was ETOPS certified?   Would there be a placard for similar indicator in the cockpit stating "ETOPS allowed" (or perhaps "No ETOPS allowed")?

Are parts of the checklist different for ETOPS/non-ETOPS aircraft?
Can the crew reasonably expect to fly whatever plane they're assigned without checking over every piece of the certification, maintenance, and dispatch?


texts: Can you help me identify a vintage airplane in a painting?

texts:
This is a recent photo of the king of Spain, Felipe VI, visiting Spanish troops stationed in Iraq. In the background there is a picture of an old plane, possibly with a propeller, that I suppose from WW2 era (more or less).

If that painting has been chosen to adorn a military installation located in Iraq and occupied by Spanish troops, I understand that it must be a type of historical significance for Spain or for Iraq.

Can anyone recognize it?


texts: Can jet airplanes operate on 'rough' airfields?

texts:
A question I've always wondered is: can jet aircraft - not turboprop in this case - operate from 'rough' airstrips. My definition of 'rough' is grass or maybe a smooth mud airfield. I know that there's the dry lake at Edwards AFB that is used by aircraft for testing.

Are aircraft such as the Boeing/ Airbus passengers series - 737, 777, 747 etc - designed for or have the capability to regularly handle these airfields?
Are there currently any operators using these kinds of fields?

I can understand that tarmac/ concrete makes for a much smoother and more pleasant surface along with the reduce risk of FOD, hidden cracks that wheels could get caught in etc.

Any other examples such as executive jets, fighter aircraft that regularly handle rough fields are more than welcome.


texts: How can L/D Max be both Best Glide speed and Max Range speed?

texts:
According to the book "Aerodynamics for Naval Aviators", best glide speed AND max range speed for propeller aircraft both occur at L/D max.
This is a little confusing because in an A36 Bonanza Vbg is 110 KIAS and Vmax range has been experimentally calculated by several sources to be about 125 KIAS.
So my explanation for how both of these are L/D Max is that L/D Max is a specific AOA, not a speed.
However, this brings me to my question.  Obviously Vbg is power off and Vmax range is power on. Assuming that L/D max is around 6 degrees AOA, with no power the airplane is descending at about 700-1200fpm (depending on prop pitch and other configuration items) at a speed of 110 KIAS.  At max range speed the airplane is level at 125 KIAS and presumably also at an AOA of approx 6 degrees.
Something seems off here.  Here is what I’m having a hard time correlating:  I teach that trim controls AOA, not speed.   If the airplane is trimmed for an AOA of 6 degrees, adding or removing power should only change the rate of climb/descent, not the airspeed.  Adding power gradually from the power off glide config at 110KIAS will eventually result in
level flight AT 110 KIAS.  If we wanted 125 KIAS we would have to add power while trimming down (lowering AOA) which means we are not at the same L/D Max AOA at Vmaxxrange that we were at Vbg.
I feel like I’m missing something here, so either one of my assumptions is incorrect, or there is another puzzle piece I’m missing that explains this. If we have to retrim for 125 KIAS level with added power, how can we be at the same l/D max AOA?


texts: How will flying through mountains cause altimeter problems?

texts:
There is an old warning on mountain flying that wind flowing through a narrow valley will cause Venturi effect, thus causing a drop in static pressure and making our little Cessna fly lower than indicated, possibly hitting some hidden mountain peak. I'm certain I know the answer to this one, but I'd like to hear someone explain it better, so here is my question:

  You fly a Cessna 172 level at FL50 (pressure altitude) with a huge
  40kts headwind. You need to traverse a narrow valley passing between
  two huge peaks on either side. Will your airplane fly at a constant
  true altitude in a straight line, or will the Venturi effect caused by
  the wind and the valley cause our aircraft to sink while passing
  through the valley?

.


texts: Is it possible for a non-towered airport to have keyhole extensions Class E starting at the surface?

texts:
(skyvector.com, modified)

The Springfield, OH airport, KSGH, is a non-towered airport with both precision and non-precision instrument approach procedures. To support these approaches, there are a couple of "keyhole" Class E transition areas; however, these particular Class E transition areas start from the surface (magenta dashed lines) depicted on VFR Sectional Charts.

I'm really confused how the Class E areas extend from the surface when the airspace directly over the non-towered airport is Class G. Is it possible that the VFR Charts are in error and the magenta dashed line should be removed or converted to a magenta vignette indicating that the Class E starts at 700' AGL?

There are several indications in my mind that this is simply depicted as an error on the VFR Sectionals:

The VFR Sectional says, "See NOTAMs/Supplement for Class E (sf) eff hrs"; however, when consulting the Central Eastern Supplement for KSGH, there is no "Airspace" item listed under the airport.  Which substantiates the VFR Sectional chart designation that the airspace directly above the airport is Class G.
Since there is no "Airspace" in the Supplement (nor NOTAMs), there is no "effective hours" as the VFR Chart suggests that there should be for the two depicted Class E (sfc) areas.
As depicted, it appears as if the a pilot could enter Class E controlled airspace and then quickly transition out of it and into Class G uncontrolled airspace as they continue on the approach.  This doesn't make sense when you consider the intent of the Class E transition areas are to help IFR traffic be provided separation from Class G traffic.
The Airman's Information Manual (para 3-2-6.e.2) describes "Class E airspace may be designated as extensions to Class B, Class C, Class D, and Class E surface areas."  It does not include Class G airspace in that list of airspaces that Class E may be designated as an extension.
The AIM (para 3-2-6.e.2) goes on to say, "Surface area arrival extensions become part of the surface area and are in effect during the
same times as the surface area." Since there is no surface area in effect, it seems to be another indicator that the Class E (sfc) is also not in effect.

Can anyone explain how it's possible for these two Class E (sfc) areas to be legitimately marked, or are they simply errors?


texts: Cargo sailboats, of the old, depended on wind direction. Like these ships, planes also save time by flying with the wind. On the extreme end, could a plane use storm fronts or hurricanes by flying in and out, in front of, or down the length of it to save time or fuel?


texts: Can lift be created without air downwash?

texts:
I was looking at the great site code7700.com, but I don't really understand their explanation of lift and drag:

     The so-called infinite wing
  displaces air for a while, but the air particles return to their
  original positions along the relative wind. The relative wind
  experience up wash as it approaches the airfoil and down wash as it
  leaves the airfoil. But the up wash and down wash are equal so the net
  effect is cancelled. Because of this, the aerodynamic force occurs
  perpendicular to the relative wind and their is no induced drag. In
  other words, all of the aerodynamic force is producing lift, none of
  it is pulling the wing backwards.

  Source

It seems this is a big confusion. Could someone just confirm that lift is created solely by the downwash and Newton's 3rd law of motion?

(Why air is deflected is not part of the question.)


texts: Does an aircraft with higher aspect ratio wings produce more wingtip vortices in a turn than one with lower aspect ratio wings?

texts: The Ta-152H was well-known for having very high-aspect ratio wings: 8.94, if I'm not mistaken. Now, compare this to the P-51 which had, if I'm not mistaken, an aspect ratio of 5.86. Does this mean that in a turn the P-51 would produce more wingtip vortices than the Ta-152H?


texts:
Radar is based on the principle of transmitting radio waves and measuring the length of time-of-flight, direction, and frequency shift of the returning reflections or echoes.

In aviation, we call this "primary radar" and we use the term "secondary radar" to denote the ATC/transponder system.

Secondary radar uses a transmitter that sends pulses that the transponder picks up and then sends coded pulses of its own back. But these are not based on reflections off the airframe.

Why then call the ATC/transponder system "secondary radar" when the principle is very different from what we might call "real" (aka primary) radar?  Or does the "secondary" here meaning "in addition to" rather than "another form of"?


texts: Can a GPS system be used to identify fixes on conventional instrument approaches?

texts:
Is the use of a certified IFR GPS receiver approved for identifying fixes defined by VOR radials, on a conventional (non RNAV) instrument approach?
For example, in KCDW LOC RWY 22, the intersections DOWDY, FAAIR and KOLLI (IF, FAF, step down fix, respectively) are all identified by VOR cross radials (TEB VOR). Can they be identified solely by reference to the GPS database?
Another example would be KABE LOC RWY 13; IZKIP is a step down fix identified by a cross radial from ETX VOR. However, the chart states:

  IZKIP FIX MINIMUMS (DUAL VOR RECEIVERS REQUIRED)

Can a GPS be used to identify IZKIP in this case?

According to AC 90-108:

  ...operators may use a suitable RNAV system in the following ways... Determine aircraft position relative to or distance from...  a named fix defined by a VOR radial.

Therefore my understanding is that named waypoints/intersections defined by VOR radials on a conventional IAP like in the examples above, can be identified using a GPS, except perhaps when the chart requires dual VOR receivers.


texts: What is the EASA equivalent of the FAA's 91.517?

texts: What is the EASA equivalent of the US 91.517 regulations (on passenger information)?


texts: Are there known cases of an airline pilot's becoming incapacitated, while in command of the aircraft, during a critical flight phase?

texts:
Are there any reported cases in which the Pilot Flying of an airliner has become incapacitated during a critical phase of flight, so that the Pilot Monitoring has had to intervene to prevent a disaster?

By critical phases of flight, I mean during takeoff, approach, or landing.


texts: Are the current seat belts used in commercial airlines safe enough?

texts:
I find myself thinking often, if the seatbelts in airlines are designed just to keep the passengers in seat or to really act as a safety belt like in cars, because in cars which go at 300kmph speed, you have the 5 point seat belt. Why isn't similar approach used for airlines, where the risk is too high.

Plus articles like these, suggest heavier / obese passengers are at more risk.


texts: Are manned balloons allowed to land anywhere?

texts:
From time to time, quite spectacular videos turn up from hot air balloons landing in unusual or even quite tight spots, such as a soccer field in Vlijmen, a road in Nijkerk, or even a small playground in Utrecht.
While I appreciate the fact that only the height can be controlled and not much else, I can't help but wonder if it's safe to do so, and if it's allowed.
I've tried searching, but all that turned up was information on landing on a farmer's field. That is allowed and there are rules for handling that.
Are there any regulations concerning landing in built-up areas? Or can a balloon land anywhere?
I'm mainly interested in the Dutch law and regulations, but wouldn't mind learning about those in other countries. I'm also curious to learn what the considerations are when choosing a landing spot.


texts: I'm trying to better my understanding of the physics behind gyroscopic instruments in an aircraft. I am aware that a spinning gyroscope creates rigidity in space by resisting applied forces. But, what exactly is the resistive force acting on the externally applied to forces, and how is it created? Is that what precession is?


texts: Is it normal for visibility to be missing from the METAR?

texts:
I have noticed at a local airport the AWOS METAR oftentimes is missing visibility measurements. In talking with other more experienced pilots, they tell me this isn't an isolated thing. They indicated that they read between the lines of the other data on the report (or other reports) to get an idea of what weather to expect.

Example:
KTPF 132055Z AUTO 29004KT SCT080 30/22 A2991 RMK AO2 PWINO

The recording always states "VISIBILITY MISSING" meaning it has a sensor and is just... not working?

My questions are:

Is it really normal to see reports without viz?
Why does this happen so often for AWOS when ATIS doesn't have problems with it?
Should this be reported to some entity (NOAA/FAA) to get these systems repaired or exchanged?
The fact that it is missing visibility information does not mean that visibility is unobstructed, right? I have heard people assume this.
If the recording says "VISIBILITY MISSING", is it indicated in the METAR somewhere?


texts: What material is used for the skin of a modern fighter jet?

texts:
Modern passenger jets/airliners use aluminum 2 to 3 mm thick as their skin, their maximum speed is 900 km/h give or take. Modern fighter jets travel at twice that speed on average.
What material is used to make their skin. If it's aluminum, is it thicker and why? Is it because of the extra cruising speed?
If specifics are required, I ask about the F-35.


texts: What does the behaviour of water on the skin of an aircraft in flight tell us?

texts:
Sometimes in damp conditions I notice some surprising (surprising to me, anyway) behaviour of water.

I'll see moisture glistening in the heads of rivets or bolts on the top of the engine pylons - that stays there for a long time (many minutes) after take-off.

Similarly, at the front edge of my window I will see a pool of water that only very slowly diminishes, seeding little drops (that become smaller and smaller as airspeed increases). Again, this pool remains far longer than I'd expect.

I'm surprised because I'd expect the evaporative and sweeping effect of the high-speed airstream to clear this moisture extremely fast, and yet it doesn't.

I suppose that despite the speed of the airstream, there are numerous small areas on the surface of the plane that are sheltered from it very effectively.

I'm interested to know what the implications of the causes of this effect are are for aerodynamics, for example how they relate to drag on the fuselage, or - where it happens on lifting or control surfaces - how their operation is affected.


texts: Will reducing the electricity power in an aircraft save fuel?

texts: I was wondering if I reduce the power consumed by the aircraft, would the generator produce less power and if that would save some fuel.


texts: What is the difference between redundancy and fault tolerance?

texts: What is the difference between redundancy and fault tolerance in the context of aviation ?


texts: What are the differences between a VOR and a VORTAC?

texts: In Brazil airspace, we do not have VORTACs to navigate (unfortunately). That's why my doubts about accuracy, the range, the possible systems/frequencies they operate, and if there is any restriction to use it to navigate.


texts: Why are turbine-powered aircraft "considered ready for takeoff"?

texts:
In an answer given to How can I politely remind ATC that I'm waiting for instructions or clearance? by @Mark, he quoted part of AIM regs:

4-3-14. Communications
a. Pilots of departing aircraft should communicate with the control tower on the appropriate ground control/clearance delivery frequency prior to starting engines to receive engine start time, taxi and/or clearance information. Unless otherwise advised by the tower, remain on that frequency during taxiing and runup, then change to local control frequency when ready to request takeoff clearance.
NOTE- Pilots are encouraged to monitor the local tower frequency as soon as practical consistent with other ATC requirements.
REFERENCE- AIM, Automatic Terminal Information Service (ATIS), Paragraph 4-1-13.
b. The tower controller will consider that pilots of turbine-powered aircraft are ready for takeoff when they reach the runway or warm-up block unless advised otherwise.

I have bolded paragraph b because that is what I am asking about here. Why is the tower controller to consider turbine-powered aircraft to be "ready for takeoff when they reach the runway"?
Why are non-turbine engines (piston?) not ready?
What does this paragraph cause the tower to not have to do?


texts: Why does flying not have any age restrictions like driving does?

texts:
I read an autobiography about Vicki Van Meter, who, with her instructor, flew across the United States at age 11 in 1993. Why could someone of that age not drive with the instructor?
Does it have to do with a different set of principles that flying has as opposed to driving?


texts: Why are cockpit instruments white on black dials?

texts: Which is easier to read:  white on a black dial or black on a white dial? It would seem most aviation instruments are white on black.


texts: Why is extreme cold weather a challenge at airports, since jets operate at extreme cold conditions in flight?

texts:
Wondering what specifically the issues are. Obviously, taking off and landing have more 'moving parts' but more curious about the actual extreme cold.

I assume the operating temperatures at cruise are much lower than ground temps.


texts: What role did the RAT (Ram Air Turbine) play on US Airways flight 1549?

texts:
An article in June 2018 Flying Magazine regarding the RAT by a Rob Mark explains that Capt. Sullunberger deployed the RAT for additional power to guide the plane down to the safe ditching on the Hudson River.

My understanding is, according to all the narratives, the book, and the movie, what saved the day (with the exception of the amazing skills of the flight crew) was the immediate starting of the APU by Capt. Sullenberger that was not even on the QRM check list,...and not the RAT.

I am wondering if both (APU and RAT) were used on that flight or the APU only? And if so, has Flying Magazine author made a mistake?


texts: Are cabin dividers used to "hide" the flex of the airplane?

texts:
Recently onboard an aircraft, a fellow passenger told me that the cabin dividers (walls) inside an aircraft are there to limit your line of sight such that you will not notice the flex of the airplane.

I know that some walls are there because of the presence of a lavatory or are actually used to create a barrier between Economy class and Business class. However as can be seen in the photo below, the circled wall is doing none of the above.

Was my fellow passenger right?


texts: Can I take the FAA CFI knowledge exam(s) based on my EASA ATPL knowledge?

texts:
One of the requirements to be a flight instructor in the USA is FAA theoretical exams.

Can I sit those exams with EASA ATPL theory basis?  Also, do I have the right to sit those exams without completing an official FAA theory exam preparation process?


texts:
This pdf from Airbus has a chart from ICAO showing the amount of correction to be applied to altimeter readings for temperatures below 0°C.

Do aircraft with flight data computers automatically correct for this?
In the US, does ATC account for this correction when assigning vectors?
How does a pilot know if they are or not?


texts: Are landing fees due for an aborted landing in USA?

texts:
Suppose I receive landing clearance for an airport that charges a landing fee, and begin my decent. Then, for some reason I have to abort the landing and instead of going around and landing there I change my plans and wish to depart the airspace. Will I be liable for any landing fees if my wheels haven’t touched the runway at such airport?

I am asking for GA in the USA.


texts: Does the stability of a mass change if the center of gravity is above or below the point of thrust?

texts:
I was wondering if it makes any difference if the mass is balanced above or below the point of thrust. See image below for clarification:

In the image you can see two configurations. The red arrow / point in both represents the force / location pushing against the mass (hull of craft). This force can be an impulse or prolonged force. the blue arrows in both represent the upwards force of the rotors. And the green arrow represents the gravity in both.
I would imagine that balancing (keep the craft hovering) would be easier with the mass below the rotors since then gravity helps pulling the center of mass back under the center of the rotors. While if the center of gravity would be above the rotors and it would be pushed to an offset gravity would help make this offset worse.
So does it makes any difference for the stability of the mass (center of gravity) is above or below the point of thrust?
just to be sure config A represents the mass and center of gravity being above the point of trust, and in config B it is below the point of trust.
I am have no engineering or physics background so please explain this as simple to me if possible :)
Let me know if this is not the right place to ask and maybe suggest me where to ask this then.


texts: Why are liquids deemed hazardous in airport security?

texts:
Airports seem to have strict rules for the amount of liquids the passengers are allowed to take on a plane.

Why is that so?


texts: How does an engine failure affect the flight of an airplane?

texts:
I'm not even close to an aviation enthusiast, but after watching some videos I found I have a deep misunderstanding on how airplanes work.

.

I've seen many cases where one of the engines fail and the plane has to fly on a single engine for a long time.

How doesn't the fact that the forces are now uneven drive the airplane to a side drift? (I'm sure this is all wrong, but I just don't understand how)


texts: How can I calculate CLmax for a wing with multiple airfoils?

texts:
How should I do the math to find the CLmax of a wing that has more than one airfoil, each with a different CLmax?

I am trying to make a model with a portion of the wing tip with a airfoil that has a low Cm, but it has a low CLmax too. So...how can I calculate my CLmax?


texts: Does an increase in lift always cause an increase in lift-induced drag?

texts:
An increase in lift causes an increase in drag. Is it always true? I am confused with two points.

Lift increases with an increase in airspeed but induced drag reduces with an increase in airspeed.
Higher aspect ratio wings generate greater lift but create less induced drag.


texts: Can passengers use headphones during takeoff and landing?

texts:
On a recent flight from KBP to KIV operated by Ukraine International Airlines (aircraft B737-800) I was asked by the flight attendant to remove my headphones both during takeoff and landing.

Is this common practice because I never saw it happen on other flights?  Are there any EASA regulations regarding this?


texts: What is the source for the flight data shown on in-flight entertainment systems?

texts:
This question which claims that an altitude of 55,000 ft. was observed on a passenger's in-flight entertainment system on an Emirates B777 made me wonder: What are the normal sources of information for the flight data displayed on passenger IFE systems?

Of particular interest are the common sources for the following information:

Altitude (Is this a pressure altitude? Indicated altitude? A GPS-measured altitude? A radio-altimeter-measured absolute altitude?)
Speed (This seems to typically be true ground speed, which I'd assume comes from GPS, but any further insight would be appreciated)
Latitude/Longitude position (Is this from GPS? INS? radionav? some combination?)
Wind speed


texts: why are turboprop/turboshaft engines rated only in horsepower and never in ft-lbs of torque like diesel engines or electric motors?

texts: I realize torque and horsepower are essentially the same measurement since horsepower is simply torque over time. But I'm curious as to why diesel engines or electric motors always provide torque ratings whereas turboprop engines are only rated in horsepower. Is there any reason for this?


texts: Would a perfectly silent supersonic aircraft create a sonic boom?

texts:
Assume that you have an aircraft that is so amazingly stealthy that it is perfectly quiet: no engine noise at all, nothing.  And, it's going supersonic.  (Maybe in a steep dive with the motor shut off.)  Will it make a sonic boom?

Would the sonic boom be louder if the aircraft was making more noise but all else remained constant?

The (excellent) answer to this question discusses aircraft size in relation to the strength of the sonic boom, but no mention of aircraft noise.  So would the amount of noise the aircraft makes matter?

Edit: by "silent" I'm not trying to imply "displaces no air" or creates no sound by its passage.  The point is simply that the aircraft itself doesn't make any noise from an engine or otherwise.  It's silent, like a bullet, or a glider.


texts: Are loops or rolls allowed in the "utility" category in any US-certified airplane or glider?

texts:
In actual practice, is there any US-certified airplane or glider where the approved flight manual, or cockpit placards, indicate that loops, rolls, or any other similarly aerobatic maneuvers other than "spins (if approved for plane), lazy eights, chandelles, and steep turns, or similar maneuvers, in which the angle of bank is more than 60 degrees but not more than 90 degrees" are allowed when the aircraft is operated in the "utility" category?

Also, in theory, would it ever be permissible for this situation to occur for a US-certified airplane or glider, if the manufacturer proved that the aircraft was safe for the maneuver in question?  Perhaps in conjunction with additional restrictions on weight or CG location?

See this closely-related question that notes that this IS the case for some airplanes and gliders certified in other countries: In the US, would it ever be legal to fly a loop in any airplane or glider that was operating in the "utility" rather than "acrobatic" category?

The current question is only asking about US-certified airplanes or gliders.


texts: What types of fuel quantity sensors are used in an aircraft? How do they work?

texts:
Can you explain the different types of fuel quantity sensors used in most recent aircraft?

Are ultrasonic tank sensors used these days? How does an ultrasonic sensor work?


texts: How does the stick pusher prevent an aircraft from stalling?

texts: The stick shakers warns the pilot of stall conditions and some fixed winged aircraft have a stick pusher which tries to avoid the stall. What is the working methodology of stick pushers?


texts: What is the rationale behind the Embraer 190's control column design?

texts: As per this picture of the Embraer 190, but also on other Aircraft, the Control column stick has a very awkward position for hands. Why is this design chosen? To me it seems that the position of the hands would be really uncomfortable as the pilots hands would be tilted at 45 degrees and not stay vertical, thus putting a lot of stress on them.


texts: How hot is the outer casing of a turbofan engine?

texts:
I am able to find temperatures inside different components of turbofan engines, but I can't seem to find what would be the temperature of the external casing/shell of the engine. For example, temperature of the casing around the LPC, HPC, HPT, LPT etc.
Information related to any type of turbofan engine would be appreciated. Thanks.


texts: How does ATC handle a controller with psychological trauma?

texts:
I've finally got around to watching Breaking Bad, (spoiler alert) in the last episode of season 2 a bereaved ATC controller accidentally causes a mid-air collision.
I am not asking whether the actual collision scenario was realistic, my question is whether the scenario of a controller with a very recent tragic loss being alone at the console is realistic. How would FAA ATC management deal with a controller who'd recently suffered a bereavement like loss of a loved one or some other sort of psychological trauma? What is the route back to work: is there a mandatory off-work policy, psychological assessment or supervision period?
I've limited this to FAA in order to keep it from being overly broad, I'm sure practices vary widely.


texts: Which connector and cables are recommended for CAN?

texts: Which mechanical connector(s) and cable(s) is/are recommended to arrange a Controller Area Network (CAN) bus communication or its aerospace counterpart ARINC 826 in the aerospace industry (civil & military)?


texts: When a B-2 takes off, does it use some device to ionise the airflow in front it?

texts: At takeoff, does the B-2 use some sort of ionization device in the leading edges of its wings?


texts: What's it like to be a volunteer at the temporary airport set up at Burning Man?

texts:
I've heard that the Burning Man festival sets up a temporary airport each year for the week of the festival and that it is staffed by volunteers.  What is it like to be a volunteer there?  Do the employees at surrounding airports find dealing with them better or worse than non-volunteer airports?

Update: Previously I asked what it is like to be a "volunteer ATC", but that is not the right terminology. I have broadened the question to be less specific.


texts: What's going on in this "confusing" TCAS Resolution Advisory video clip?

texts:
There's a clip on YouTube from a pilot of a 747-200 whose TCAS system issues a "confusing" RA:

What exactly is happening here?

For those who can't watch the video right now, here are some frames:


texts: Why and how would I land straight-in from a circle-to-land approach?

texts:
I'm currently studying for an IR (US). One of the exam practice questions concerns an IAP having only circling minimums, and references 5-4-20(c) of the AIM, which reads:

Straight-in Minimums are shown on the IAP when the final approach course is within 30 degrees of the runway alignment (15 degrees for GPS IAPs) and a normal descent can be made from the IFR altitude shown on the IAP to the runway surface. When either the normal rate of descent or the runway alignment factor of 30 degrees (15 degrees for GPS IAPs) is exceeded, a straight-in minimum is not published and a circling minimum applies. The fact that a straight-in minimum is not published does not preclude pilots from landing straight-in if they have the active runway in sight and have sufficient time to make a normal approach for landing. Under such conditions and when ATC has cleared them for landing on that runway, pilots are not expected to circle even though only circling minimums are published. If they desire to circle, they should advise ATC.

I'm having trouble understanding the bolded sentence. What does it mean to land straight-in from an approach that is more than 30 degrees from runway alignment?
I've been understanding a circling approach as something like a pattern landing where you start the maneuver once you have passed the FAF and have - and can keep - the runway environment in sight. But this seems to imply something different. What am I missing? What does "a normal approach to landing" mean here?


texts: What are the consequences of attaching an unused extra engine under Boeing 747 wing?

texts:
It turns out Boeing 747 can carry an extra engine under its left wing in case there's need to transport an engine somewhere far away. The engine is attached between the body and the left inner engine and isn't operational during such flight.

What implications does that have on the airplane operation? I guess drag is increased notably and also drag increases only for left wing and so the plane should tend to well, turn left in case engine thrust is equal on both sides of the plane so now engines under right wing have to produce more thrust or something like that. Also the engine weighs quite a lot so less cargo may be put into the plane. Also fuel consumption increases and flight range decreases accordingly.

Is that all? What are the consequences of attaching an extra engine under Boeing 747 wing?


texts: What are the differences between EASA (UK) and CASA flight training?

texts:
I'm a British citizen living in Australia who is tossing up on whether to train back home or in Australia. Given the sheer amount of complex information out there, I was wondering what the differences are between the PPL, CPL/ME/IR, ATPL theory & MCC/JOC training in Australia versus in the UK (or the EASA region as a whole), in terms of hour requirements, syllabus, technicalities, rules, licencing system, etc...

A comprehensive guide from those who perhaps have experience or knowledge would be great!


texts: What climb rates can the Airbus A320-200 achieve and which climb rates are commonly used for normal flight operations?

texts:
In relation to AirAsia flight QZ8501 officials have been quoted as saying:

  "It is not normal to climb like that. It's very rare for commercial planes, which normally climb just 1,000 to 2,000 feet per minute. It [climbing at 6,000 ft per minute] can only be done by a fighter jet."

Two parts of that statement struck me:

The rate of 1,000 to 2,000 feet per minute is stated as "normal", not "maximum"
The claim that only fighter jets can climb at 6,000 feet per minute.

My question is then:

What is the maximum climb rate that an AirBus A320-200 such as the one involved in this incident could achieve with out stalling? (Including configurations and operations outside of "normal")
If it is less than 6,000 feet per minute on the A320-200 can any commercial passenger carrying aircraft in operation today exceed 6,000 feet per minute? (I'd assume Concorde could, but that's no longer in operation)


texts: What happens if an A320 goes to full throttle with the parking brake set?

texts:
The question is simple: what happens?

Is the aircraft going to stay stationary, or will the engine power overcome the brakes? I'm assuming everything is fully functional.

I know the FCOM says not to exceed 75% N1 with the parking brake engaged, but if we did, what would happen?


texts: Why does only one hydraulic intake line from the reservoir have a filter on the Arrow II?

texts:
This is a portion of an Arrow II landing gear hydraulic system diagram.

I noticed that there are two intake check valves, one located on each side of the pump, that would allow flow from the reservoir.  Only one side indicates the existence of a filter.

Why do both sides not have a filter if they are both from the reservoir?


texts: Does CG location affect the stability of the Dassault Falcon 7x while on the ground?

texts:
Can any one please explain me the basic static stability of Falcon 7x on ground at aft most CG which is 38.5%MAC=12.63498m ... because as per my hand calculations i m getting around 2% load/weight on Nose landing gear... is there something wrong with my calculations or the CG doesn't really affect the aircraft stability...?

I have used following method to determine the load

$$Fn_{min} = \frac{Bm_{min}* W}{B}$$

$Fn_{min} = 4090.817398$, % of load $2.093923332$ where $Bm_{min}$ is distance from Main Landing gear to the aft most cg = $0.201 \mathrm{m}$, $W$ is the design limit weight $=19915 \mathrm{kg}$, $B$ is the wheel base $= 9.5644 \mathrm{m}$.


texts: Are remarks in the Chart Supplement (A/FD) "regulatory" or "advisory"?

texts:
StallSpin's answer on the recent question about VFR traffic patterns has got me thinking about the "Remarks" section of the Chart Supplement (formerly the Airport/Facility Directory).

We are all taught in training to review the Supplement entry for airports we intend to visit (part of FAR 91.103's "become familiar with all available information" requirement), and to comply with any restrictions noted - typically things like "no touch-and-go landings", "Standard traffic pattern required of all aircraft", "Prior Permission Required for jet aircraft", etc.

Aside from it being The Right Thing To Do, and avoiding the possibility of local fines/sanctions, are the remarks in the Supplement "regulatory" such as to require compliance, or are they advisory where compliance is encouraged but not mandatory?


texts: Why might an altimeter read incorrectly by 4000ft after sitting on the ground for some time?

texts:
My friend landed at Timaru Airport and when he put the aircraft into the hangar the altimeter reading was approximately 100ft [airport elevation is 89ft]. When he got back to go flying two weeks later the altimeter reading was over 4000ft.

He replaced the altimeter with a new one and now the same thing has happened again. Has anybody got any idea about what has happened?


texts: How far can A&P mechanics operate aircraft under US regulations?

texts:
Anytime an A&P mechanic wants to test the updates/fixes made to an aircraft's systems or any part for that matter, what are the laws (at least under the FAA) that legally allow them to operate an aircraft?

I've personally seen GA airplanes being taxied (in non-movement areas so far) by A&P mechanics. Is there a law that states that they can/cannot operate that very aircraft on a taxiway (movement area)?

What about larger aircraft (business jets, airliners etc.)? Do authorized mechanics always need a licensed (and appropriately certified with the required ratings) pilot all the time when testing the aircraft after repairs?

Finally, what about military jets? I once acquainted with someone who worked on military jets' electrical systems, but was never licensed to fly. Would he solely rely on the PIC's conclusion about the condition of the jet?


texts: What is the required cloud clearance in G airspace when there are clouds just above in class E airspace?

texts:
This is my first question here and I am about to start my Private Pilot License (PPL).

Now I am flying in my Flight Simulator X. So, I am at KDKK airport. It has an elevation of 692 MSL . I got my ATIS report 2100 MSL scattered and 3000 MSL broken. The airport is in class G and the weather minimum here is clear of clouds.

At 1200 AGL we have class E airspace and 500 feet below clouds rule applies here. The question is: flying at 1800 I will still be flying in G airspace, but will not comply with 500 feet class e rule and will be closer than 500 feet to the clouds. Is it legal?

And the second question: still didn't find clear definition of "clear of clouds". Is that mean that there are no clouds at all? or it could be clouds, and I can fly very close to them, but I can't get through the clouds?


texts: What is this jet seen in the Falcon Crest TV series?

texts: This is another jetliner from "Falcon Crest" I'm trying to identify.  It was visible briefly in episode # 194 <8.11> "True Confessions" (1989).  Thanks for your help!


texts: How do balloon pilots avoid birdstrikes?

texts:
Balloons, by their very nature, are at the mercy of the wind, and can’t maneuver out of the way of other objects except by (very slowly) climbing or descending.  For this reason, mid-air collisions are fairly common whenever and wherever large numbers of balloons occupy small volumes of airspace (especially because this inability to take evasive action essentially restricts most balloons to uncontrolled airspace, which, in most places, is a very small layer immediately above the ground); fortunately, as balloons are very slow1 and very soft, balloon-balloon MACs are, generally, completely harmless (except in the extremely rare cases where a balloon rises into the basket of a balloon above it and gets its envelope ripped open).

Birds, on the other hand, are not necessarily at the mercy of the wind, are largely concentrated at the low altitudes where most balloons operate, are far more numerous than balloons (which is probably still the case even in the middle of a balloon gathering), and tend to come with a lot of inconsiderate pointy bits (beak, claws, probably other things too).  Unlike with heavier-than-air aircraft, where a birdstrike usually just means a few dents, or, at worst, some unscheduled engine maintenance (although, as always, there are exceptions), a balloon could, if hit by a bird, easily suffer a catastrophic envelope rupture, followed quickly by (at best) a hard forced landing, or (at worst) rapid unscheduled lithobraking.2

How do balloons and birds avoid each other?

1: Not necessarily slow relative to the ground, but definitely slow relative to each other (since they’re being pushed by the same, or mostly the same, wind), which is what counts in a MAC.

2: Like the chapter in The Twenty-One Balloons where the protagonist’s houseballoon is punctured by a seagull, and he has to make a forced landing on a beach.


texts: If a CDI needle is deflected to the right, why is the aircraft off track to the left?

texts:
Consider a CDI as shown below. If the CDI is set to FROM and the selected course is north, but the needle indicates three dots to the right (each dot signifying a 2 degree deviation from the selected course, i.e. 6 degrees in total), then why is the aircraft's radial at 354 degrees?

I associate a right movement of the needle with a "positive deviation", which would correspond to the aircraft's radial being at 006 degrees.


texts: Why do modern jetliners provide Thrust Reversers at all in their design decisions?

texts:
Let's start with the following knowns (please correct me if I am wrong about any):

The braking force provided by the wheel brakes is much larger than that by the thrust reversers
One is not allowed to does not take credit for reversers when calculating landing distance in most aircraft. (A few exceptions exist)
Thrust reversers add quite significantly to the weight and complexity of engines
An improperly deployed thrust reverser can be critically dangerous and hence many redundant systems must be provided to prevent unwanted deployment
Modern civillian aircraft never rely on reverse thrust during flight
In the history of aviation incidents quite a few have been related to reverser problems or procedure errors.

In the light of this why aren't more large civilian aircraft designed that use only wheel brakes + spoilers to do all their braking?

More specifically, suppose you had to re-assign the braking force provided by the reversers in the initial rollout to spoliers alone how much more spoiler area would one need to provide?

Overall, spoilers + wheelbrakes seem far more docile and benign than the complexity and risks associated with reverse thrust?

What gives?

PS.

Are the any modern large passenger jet aircraft that don't have reversers at all?


texts: If an Osprey found itself unable to rotate its engines to vertical, what would be the emergency procedure for landing?

texts:
Let's say an Osprey appears to be flying normally in forward flight. In preparation for landing, the pilot tries to command the engines to begin tilting to vertical, but nothing happens. What now?

If there's a manual way to crank the engines up, that's not working either.


texts: What's the maximum seat configuration for a 747 that is actually used?

texts:
I'm curious what model and configuration of the 747 has the most seating capacity actually used somewhere in the world. The Wikipedia page lists "typical" seating, maxing out at 467 (the 747-8). But that list also shows "Exit limits" on the 747-400 as 550 or 660 depending on exit type, and the 747-400 article claims the 747-400 can be configured in a single-class setup with 660 seats (matching that upper exit limit). The 747 article says:

  In Japan, 747s on domestic routes were configured to carry nearly the maximum passenger capacity.

The linked article "isn't available in my region" but a copy viewed via the wayback machine says:

  At the opposite end of the luxury spectrum is what All Nippon and Japan Airlines have done to a few of their 747-400s for high-density domestic routes in Japan.

  They carry nearly 600 passengers in one class.

So, is the 660-seat 747-400 configuration actually used anywhere? Or if not, what's the largest actually used, and what model is it?


texts: Why should the leading edge be blunt on low-speed, subsonic airfoils?

texts: I have read that is to help the flow remains attached, but I do not understand the physical principle.


texts: How are military jets given official names?

texts: How is a military jet given a nickname? Does the manufacturer name the plane? For example, did Lockheed Martin name the Raptor (F-22) and Lightning II (F-35)?


texts: Why does the yoke "stick" in a turning position?

texts: As you make a turn, an airplane does not naturally straighten itself out (like a car does to some extent). Are ailerons engineered to stay in whatever position they are placed, or is this simply a byproduct of aerodynamics?


texts: Does Wing Area vary with angle ot attack?

texts:
For a very basic airplane, say like Cessna 150 is built with Wing Area (S)=15 meter squared (say it 15m*1m). In another part said that the Lift (L)=0.5*rho*(V)^2*Cl*S. Mean, Lift is affected by the wing area. Yes, it is clear. My question, should I consider the wing area as fix area during the take off, cruise, and during landing? If angle of attack of the wing is 15 degree during take off, what is the wing area?

From the Lift formula above that is written here, S (wing area) is planform (projected). Where it to be projected? If like above, if during the take off the Angle Of Attack is 15 degree, what is the wing area? Very appreciate if explanation provided with reference.


texts: How does the wheel speed sensor in a Boeing 777-300ER work?

texts:
I do have a maintenance manual that I found on Internet, but it doesn't have anything about the wheel speed transducer.

Any pics along with the information would be helpful.


texts: Why not make the touchdown zone of runways wider than the rest?

texts:
Reasons:

Save money by making the rest of the runway narrower
Larger margin of error left and right
Easier to turn around, if necessary

And if the reason that it isn't done is merely for regulation/legal reasons: Is this something that would be practical if it were allowed?


texts: Why are the AOA sensors placed outside the aircraft?

texts: Why should the AOA sensors be placed outside the aircraft? Is it not the angle between the chord line of a wing and a vector representing the relative motion between the aircraft and the surrounding air, in which case, is it not possible to measure the AOA with a simple instrument inside the cockpit, which eliminates malfunction due to exposure?


texts: Does the nearest function on a G1000 allow for listing of anything other than nearest airports?

texts:
In non G1000 GPS systems, I have seen several pages for selecting the nearest airport, VOR, NDB, intersections, and waypoint, but in a G1000, I can only seem to get a listing of the nearest airport, but have to manually enter VORs.

Am I missing something, or does the G1000 not have nearest functionality for these other categories of identifiers?


texts: What is the wingtip station number on a Boeing 747?

texts:
In the figure we can see the station line even though it is not clear. I'am using that picture just for an example to make the question clearer.

Main question

What is the station number for wingtip on a Boeing 747? (fuselage station and water lines)(If possible the butt lines too)

I tried searching the internet for the station number and couldn't find what I'm looking for. Or am I looking at the wrong place to find it? Where to find the number if you don't have access to the aircraft maintenance manual?


texts: What is this biplane from an old photograph?

texts: Copyright photo by Real Photographs No 334


texts: Is the IOSA useful even if not all airliners are IATA members?

texts:
Given the two facts:

According to wikipedia, the IATA represent a little more than 80% of available seat kilometers. It makes sense as some airlines are not IATA members.
Under each region over the world, an organisation is dedicated to make sure civilian aviation is safe, following ICAO's standards (EASA in Europe, FAA in US, ...)

As I understand, the IATA has its own certification program (IOSA). It seems to me that it doesn't make sense: it doesn't cover all commercial aviation (some low cost carrier are not part of the IATA and still represent a significant part of the traffic), and its purpose is the same as other civilian organisation (FAA, EASA,...) acting under the ICAO's rules.

I'm quite sure I'm missing something, but is the IOSA useful as it does not cover significant airlines and its purpose seems to be covered by other organisations?


texts: Why do stealth aircraft generally lose in maneuverability?

texts:
Whilst stealthy built aircraft have (or claim to have) many anti-detection systems, they seem to have to compromise on less maneuverability features, and even have to keep their missiles inside, not on the outside.

Why is it so these days?

Based on the above what could be the tendency for the future military aircraft (the jet fighters in particular)?


texts: What are normal landing separation minima?

texts: As far as I know we have separation minima of 10 minutes in horizontal flight, so do we have any equivalent separation minima for landing? If so, how it is possible to land two aircraft in a very short time, like 40 seconds? And doesn't this create wake vortices?


texts: What does this black triangle placard on board an A320 denote?

texts: Just out of interest whilst travelling aboard a British Airways A320-232 G-MIDT on the 9.45 BA shuttle service (LGW-GLA) in seat 10F I noticed a placard above the window  of seat 9F. Given this seat was two rows forward of an overwing exit I was wondering if it was related in any way.


texts: Does the power behind the engine make any difference to how strong the thrust is?

texts: What difference does horsepower make? If the engine can spin the propeller fast enough, why does it need power behind it?


texts: How could MH370 fly west when satellite pings went east?

texts:
I have a question perhaps best demonstrated with this image:

Malaysia published two maps with the preliminary accident report which allege MH370 flew west from Penang to MEKAR (above Aceh Province) and then between 18:25 UTC and 19:41 UTC flew west into the Indian Ocean.

The problem is the Burst Offset Frequency chart published 24 March shows a frequency drop after 18:25 UTC signifying flight away from the satellite.

After MH370 allegedly emerged from the Straits and turned south the track which Malaysia's Preliminary Accident Report claims MH370 flew (based on their analysis of the BOF chart data) the track makes even less sense because the distances away from the satellite continue to increase.

And this image shows the distance relationship with the satellite:

There are also other (non satellite) reasons to question the validity of the alleged track through the Straits of Malacca. First is the claim MH370 was seen flying west by radar at Surat Thani in Thailand. That radar has a published maximum range of 200nm. Kota Bharu is 240nm away from Surat Thani.

This is not the only reason to doubt the alleged MH370 flight though the Straits. Malaysia presented this image to Chinese relatives at the Lido hotel in Beijing on 21 March and told them it was a military radar image from Butterworth of MH370 in the Straits of Malacca. They said it crossed the island of Pelau Perak at 18:02 UTC and disappeared at 18:22 UTC.

The image however omits other aircraft known to be present at the same time:

Worst inconsistency of all however is this, the radar image does not even come from the Butterworth radar. The real military radar used by Butterworth is a Thales Raytheon GM400 which has a screen display like this:

I don't understand how so many supposedly intelligent "experts" and journalists have managed to be deceived for so long except to say people believe only what they want to believe and shut their eyes to the truth.

Australian, Malaysian, Japanese, New Zealand and Chinese taxpayers collectively forked out $90m wasted taxpayer dollars for a search at the end of this projected BOF track in April which turned up no result.

My question is how does this mutually incompatible information prove MH370 flew west through the Straits at all?


texts: What names are used for certified "mechanics"?

texts:
While watching a documentary on the the UK Red Arrow aerobatic team, mechanics were sometimes called "tradesmen", "technician", or "engineer".

In the US they are commonly called "aircraft mechanics" or an "A&P".

What other designations are used for certified aircraft "mechanics"?

image source


texts: How does corrugated skin influence the effectiveness of ailerons?

texts:
Recently I found a paper about incorporating corrugated skins in aircraft called 'Corrugated composite structures for aircraft morphing skin applications' by C. Thill, J.A. Etches, I.P. Bond, K.D. Potter and P.M. Weaver

Source: Paper PDF

The paper talks about how the application of corrugated skins might provide benefits in morphing skins. The paper mostly talks about the structural benefits, as requiring less force to change the shape. Even if the structure might be covered with an aerodynamic surface, I'm still interested in the aerodynamic properties of a corrugated surface.

If there's a wing surface with a corrugating perpendicular to the flow, as shown below (flow coming from the left).

Image taken from Paper PDF

How will such a surface incluence the effectiveness of non-corrugated ailerons?

I image such a surface would lead to a much thicker boundary layer, thereby greatly reducing aileron effectiveness.

I'm mostly interested in large corrugations(~50mm) and low speeds(~80km/h). I'm not asking about the lift generation of the surface itself, only the effect on a non-corrugated aileron.


texts: How to leverage Lynx NGT-9000's integrated GPS/WAAS?

texts:
I’m inheriting an IFR capable 1964 Cherokee 235 that is not equipped with a GPS. I’m looking at installing a Lynx NGT-9000 to get ADS-B compliant and gain the traffic and weather information.

Is there any way to leverage its integrated GPS/WAAS to enable LP/LPV approaches and file IFR direct? I don’t want to over panel this plane.


texts:
Since J-10 originated from the IAI Lavi project, people assume that they are very close to F-16 in terms of maneuverability.

How can we compare the maneuverability of the F-16 Block 60 and J-10C?


texts: Can you use a mode 3AC interrogator in EU airspace?

texts:
I'm investigating the possible application of mode 3AC interrogators in EU airspace.

My experience is unfortunately limited to North America, and I'm unfamiliar with Mode S systems / function.

All the information I've managed to find describes mode S trabsponders as "backwards compatible" but fail to go into detail.

Is the backwards compatibility seamless and simultaneous?, Able to reply to both mode S and mode 3 interrogators in real time? Or a toggle switch between modes, in which when mode S is selected mode 3 interrogations will be ignored?

Do European standards allow mode 3A/C interrogators to operate within their airspace? Could this cause interference with local mode S infrastructure?

Are there any other potential concerns with operating a mode 3 interrogator in EU airspace?

To clarify I am speaking from the perspective of a ground station. As in using a mode 3AC SSR on an airport in EU airspace.

Any information would be greatly appreciated, thank you.


texts: What could cause the APU on a Boeing 777 to fail and also trip the GPU?

texts:
I am a cargo aircraft loader at Heathrow and while we were offloading cargo, pallets and baggage containers from a Pakistan Airlines B777, the aircraft's Auxiliary Power Unit (APU) failed. It made matters worse when we attached the Ground Power Unit (GPU) ground cables to the aircraft nose because the GPU went into trip mode. This resulted in a complete loss of power and we were unable to open up the front and rear cargo doors. The loading systems' Power Drive Unit (PDU) also failed.

My team leader played with the GPU leads and set them at a certain angle where the trip mode stopped and we offloaded the airplane. What could cause this APU failure, and why would the GPU trip? Is this a safety issue if airlines operate a non-functional APU on their aircraft?


texts:
I saw this plane on a remote ramp at BKK today.  What is the purpose of aluminium foil on the wheels?  Does it mean the plane is in mothball?  I don't see other planes, even in maintenance, with aluminium foil on the tires.

In respect of the photo's license, I am the owner of the picture and authorize anyone to use my photo for any purpose except illegal activity.


texts: Is it true the F-16 has never lost a dogfight?

texts:
(Source)

I have heard the F-16 has never lost an air-to-air dogfight - is this true?


texts: What is this molten metal coming from the engine of an Avro RJ 100?

texts:
Yesterday I flew in an Swiss Avro RJ100. As soon as we landed I was shocked to see some sort of molten metal which was incandescent and glowing red dripping down from the vent as indicated in the picture. It was almost catching fire! I was suprised to see immediately the maintenance van pitch up to the plane when we didn't even get to a stop. Is this normal?

This image isn't of the problem flight, but shows where the problem was.


texts: Why do airline schedules start in March and October?

texts: Is there any specific reason as to why airline schedules for the summer season start around 27 March and winter season around 27 October? Thanks.


texts:
If I had a plane that could take off and land in a short distance (eg., the SD-1 Minisport), do I have to use a recognized airport in order to land in the US?  Or can I just land anywhere so long as it's class G airspace?

FYI, this question is for non-emergencies.  IE., if I just wanted to land there because it was convenient.


texts:
At some point maybe after around 8 to 10 decades we may end up with a situation where the crude oil wells get drained up due to massive extraction and increasing demand for gasoline and ATF. What would be the another option for the conventional fuel system?

Some of the prototypes like solar impulse, explorer etc. are for small light weight aircraft.  What about the massive aircraft like the Boeing 707,747 Airbus a380 and fighter jets.

My point is can't we make something like nuclear propelled aircraft? By designing some kind of miniature size of reactor or maybe any other way of non conventional propulsion system to over come the future oil crisis.


texts: How many kilowatts to get an electric 747-8 airborne?

texts: Reading about the Airbus E-Fan and it's dual 30 kW thrust fans caused me to wonder: assuming the need for four electric fans, how many kilowatts would be required to power each fan with enough thrust to get a Boeing 747-8 airborne?


texts: Does anyone know if RHP (assumed to be rotor horse power) is equivalent to SHP (shaft HP)?

texts:
I was recently reading a NAVAER aircraft characteristics summary of the proposed XHCH-1 helicopter of 1951. In the engine section it gives the engine power in "Rhp" and later in a 1956 summary gives the value in Brake HP (Bhp). See https://www.alternatewars.com/SAC/XHCH-1_CS_-_1_November_1951.pdf
Does anyone know if there is a difference between RHP and BHP. I'm "assuming" (and I stress assuming) that RHP is 'rotor horse power' and equivalent to shaft horse power. I'm again "assuming" that the technical description simply changed over the last 70 or so years.
Any thoughts or suggestions from any learned person out there? Thank you, much appreciated.


texts:
Some planes have this large protruding part at the wing root. If my understanding is correct, it's a wing strake and it improves lift at high aoa via vortex induced lift on the rest of the wing. I have 3 questions.
1:If that's true, what are it's downsides?
2:This seems like a desirable thing, why don't more planes have it?
3: What does it have to do with canards? Every single canard aircraft has them, Rutan planes, Velocity planes, basically every canard plane I've ever known has them, and no conventional plane I can think of has them. What's the connection here?


texts:
What are the construction guidelines to geometrically build a NACA intake (submerged intake) for aircrafts?

The relationships between the aerodynamic performance parameters (ram recovery, drag, and mass flow rate) with the geometric parameters (width of the intake, height, length of ramp, ramp angle, inlet radius and angle, divergent wall angles, divergent wall curve radius, etc...) would provide a guide to begin the construction process for a base model, which could then be refined with further investigation for a specific aircraft.

There are even tools to construct the curve of the NACA intakes. However, the background of the tool as its aerodynamic justification isn't available or at least not found.

I would therefore greatly appreciate any material on the correct geometric construction of NACA intakes.


texts: What does stick fixed and stick free longitudinal stability mean in simple terms?

texts: What is the significance of stick fixed and stick free terms in aircrafts with mechanical control and modern fly-by-wire control?


texts: Is it possible to create Interference Drag without physical surfaces conjoining?

texts:
Interference Drag is when boundary layers mix/combine, usually it's caused by pieces of metal conjoining (wing struts/gear retracting).

Is it possible for interference drag to be created without having physical surfaces connecting? Rather, is it possible for boundary layers to form/mix without a physical surface?


texts: Why was the VC10 unusually prone to reverser-induced buffeting?

texts:
According to Wikipedia, the original (“Standard”) version of the Vickers VC10 had thrust reversers only on the outboard engines, as putting reversers on the inboard engines produced severe tailplane buffeting and attendant fatigue problems.  The larger, heavier Super VC10 had modified and repositioned engine pods in order to resolve this issue, allowing the Super to have reversers on all four engines; despite these changes, the buffeting from the inboard reversers proved to still be severe enough to necessitate their near-immediate removal.

In contrast, the vast majority of jetliners with tail-mounted engines (leaving aside oddities like the F28, which has no thrust reversers at all, and the Il-62, which has four engines, with reversers only on the outboard pair, like the VC10) experience(d) little or no trouble with reverser-induced buffet, even though their engines - like the VC10’s inboard pair - are (or were) located immediately adjacent to the empennage, and, thus, should be just as prone to inducing buffet as the inboards on the VC10.  1-11, DC-9, 727, Tu-154, F100, CRJ900 - all have (or had) tail-mounted engines with thrust reversers, but none experienced the buffeting problems seen with the VC10’s inboard engines.  Why is this?


texts: How did Airbus fit 6,340 gallons more fuel into the A359?

texts:
Bloomberg posted an article that says, among other things, the A350 ULR variant increases range by utilizing "additional space already available in the existing tanks to carry an extra 6,340 gallons of fuel."

What is the deeper technical explanation, or why not use this space in the regular A359 variant?


texts: How much does an airliner cabin elongate at altitude?

texts:
How much (about) is a commercial plane's cabin elongated at cruising altitude, due to interior-exterior pressure difference?
Of course there should be a slight shrinkage because of temp difference, but I estimate that overall a 30m cabin  should be elongated by few centimeters.


texts: Are modern airliners still stressed-skin aircraft?

texts:
Can modern airliners still be seen as stressed-skin aircraft?

i.e. is the skin, whether it be aluminium or composites, still an integral structural member of the airplane?


texts: Why are there fewer stages in the turbine than in the compressor of a turbine engine?

texts:
I'm a student interested in aviation. I'd like to understand why the turbine section has fewer stages than the compressor section in a jet engine.

What would be the effects of adding stages to the turbine, or to the compressor? How is the optimal number of stages determined?


texts: Can quadcopter-like UAVs ever get significantly quieter? Any candidate technology?

texts:
The light weight quadcopter and hexacopter UAVs that can cary say 2kg to 20kg payloads for "delivery" produce enough noise that a steady stream of pizza and book deliveries might not be so welcome in many populated areas.

Are there any candidate technologies that can significantly reduce the noise heard by people on the ground? One possibility is of course to fly higher, but that may not always be possible or desirable, and I don't think they'll be deploying pizzas and books with little parachutes from 500 or 1000 foot heights.

Better propeller design? Cleverly ducted/muffled thrust? Anything?

I'm sure possible techniques will interfere with thrust, so anything that has an impact of less than 50% would count here. Batteries will continue to get better over time, but I can't imagine much more innovation can be done with propellers.

I'm not looking for guesses, but it doesn't have to be proven on this scale either. My feeling is that there really isn't anything besides distance that can help very much.


texts: May a Cessna 182 land on a major, high-traffic airport, say EDDF (Frankfurt)?

texts:
Some 30 years ago a family's friend owned a TR-182 Skylane (Turbo,
retractable gear) and we sometimes flew around here in the Rhine-Main
area around Frankfurt. Of course he used EDFE (Egelsbach) for take-off
and landing. I remember asking him if it would be possible/legal to land
in Frankfurt with his Cessna 182.

As I recall, he said they would likely reject such a landing as they
wouldn't really appreciate us occupying a runway and make the big planes
wait for our tiny one. Even if we were allowed, the landing and parking
fees would be in such high regions that no one in their right mind would
be willing to pay them.

The only exception, he said, would be an emergency. In that case we
could very well land in Frankfurt but must be prepared for massive
interrogation afterwards if the emergency wasn't obvious.

I'm not asking about a C182 specifically but about "small" GA planes
(say MTOW below 2-3 t) on "big" German airports such as Frankfurt.


texts: Why does the B777-200 freighter not use the letters I, N, O and Q for deck positions?

texts:
The B777-200 Freighter has positions on the main deck to describe how the cargo will be loaded in a left to right sequence. They are identified as A, B, C, D, E, F, G, H, J, K, L, M, P and R.

What is the reason that the letters I, N, O, and Q are omitted?


texts:
When flying to Teterboro, NJ (KTEB) and cleared via the JAIKE THREE ARRIVAL from Flat Rock (FAK):

What does ATC expect when they give a clearance like:

  N1234, Descend VIA the JAIKE THREE ARRIVAL

Then, what if they give the next clearance when over JAIKE:

  N1234, Descend and maintain 7000

I believe that there is a difference in ATC procedures over whether or not the crossing restrictions still need to be made between US and Canadian rules, what should be done in both cases?  (And out of curiosity, does ICAO have anything to say about this situation?)


texts:
How does the radio altimeter reading change with the bank angle?

Following example:
Let's say, we're flying at 1000' AGL and a bank angle of 0° above a endless flat surface. The radio altimeter shows 1000' as well.
Now if we roll to either side to a bank angle of 10° and maintain 1000' AGL, what does the radio altimeter read now?

Does does the radio alt increase accordingly or is the radio altimeter adjusted to always face down?

I'm especially interrested in the way how Airbus handles this situation.


texts: How much does it cost to add a glider rating to a PPL?

texts: In Europe, how much does it cost to learn to fly gliders if you're already a private pilot? I am one, so I already have the medical and theory etc. but what cost can I expect for a GPL on top of a PPL?


texts: Is it safe to fly if the flaps won't retract on ground?

texts:
The Piper Archer (PA-28) i had this morning had issues returning flaps to normal after being fully extended ON THE GROUND. It required a non trivial amount of push on the air-frame itself to restore the flaps to the original position after having retracted the flaps using the stick in the cockpit.
I was told that "this is normal" and that the spring might be a little worn but that it wouldn't cause any safety issues, but none of the other Piper Archers I've flown have had this issue. I would add that it was a cold day (just above freezing) but the plane fully fully de-iced.
Is it reasonable the fly the plane?
Would you be worried? If you refused to fly the plane in that condition despite booking, would you accept the rental to be charged partially?


texts: How are light weight fillers made for fixing dents on airplane wings?

texts: Say an airplane wing was damaged by hail, it's really costly to replace the panel due to inaccessible rivets and what not, and the back of the panel is inaccessible to mechanically remove the dent.  How are light weight fillers made to fill the gap? Not like the heavy stuff like Bondo that is (was?) used to fill dents on cars, piled on and then sanded smooth.  Airplanes need something light weight.


texts: I've heard that a "Flat Rated Engine" is an engine where the power is reduced to keep the internal temperature within certain limits when the ambient temperature is above a certain point. Is that correct? How does it work?


texts: Why must some aircraft get permission to start their engines?

texts:
Some larger airliners must get ground control permission before starting their engines.

Is this based on size? Does a Learjet need permission?
Is this just turbines? For example does a DC3 or DC6 need permission?
How would a pilot find out? Does the airport supplement or some other document show when it is required?
Are there exceptions such as jets parked on remote ramps, not at gates, non-commercial?

I know from flying small recips that I never needed permission anywhere in the US or Canada - but certain airliners did.

This airport in Australia says they enforces their right for the engine start. Part of the authorization comes from environmental noise control.  townsvilleairport (Australia).

Van Nuy - US, "All  aircraft  with  engines  capable  of  producing
more  than 14,750  lbs.  of  thrust must  be  pushed  back  or  towed  onto  the  taxiway  prior  to  engine  start." (Airport ops) (Of course you need ground approval prior to entering a taxi way...)

When working at Anchorage International, Alaska with Continental 737-757, we had to contact ground control. We could start the engines at the gate while doing maintenance; there were no ground crew around. We started the onboard APU, turned on the red strobes, got permission from ground, then started the engines. I never read a document, this info was relayed to me by my supervisors.


texts: Is there any instrument similar to a compass but which I can electrically drive?

texts:
I would like to build a home weather station with analog instruments showing for example temperature, wind speed and wind direction.

I would like to use a salvaged flight instrument to show the wind direction: I have a wind vane transducer that convert the wind direction in an electrical signal and I would like to use this signal to drive a suitable instrument.

The instrument I have in mind is like a magnetic compass but while the magnetic compass does not need an "input signal" I need to drive the needle.

I have a look at a heading indicator

but it seems to me that the "airplane needle" is fixed while the 0-360 graduation is moving. I need, like in a compass, a fixed graduation and a moving needle.

For example this seems fine to me but I have no idea what instrument is:

MASCO SERV. CORP.
DALLAS, TEXAS
PART NO. 503A
SER NO. 2500


texts: When there is a holding pattern assigned by a civilian airports ATC, do military aircraft get first priority over landing?

texts: When a military aircraft is landing at a civilian airport, and a holding pattern is in place, do military aircraft get to skip the que, or join in earlier in the holding pattern?


texts: What was the lift equation used by the Wright brothers?

texts:
NOTICE: The modern lift equation and the lift equation used by the
  Wright brothers in 1900 are slightly different. The lift coefficient
  of the modern equation is referenced to the dynamic pressure of the
  flow, while the lift coefficient of the earlier times was referenced
  to the drag of an equivalent flat plate. So the value of these two
  coefficients would be different even for the same wing and the same
  set of flow conditions.

Above is a quote from a NASA website (emphasis mine). It's new for me that the Wright brothers applied different calculations to their plane. So, what was the equation used by the two brothers?


texts: At what rpm does the tip of a 54" propeller start to incur mach losses?

texts: At what rpm does the tip of a 54 inches propeller start to incur mach losses? The max rpm of my engine is 3600.


texts: What characteristic my canard needs to have when the canard also carries a pair of engine?

texts:
I am in 3rd year Aerospace Engineering and trying to do a preliminary design of an airplane. My design has a front wing that also has an engine at its root on both side of the fuselage.

There is another engine with thrust vectoring nozzle at the back of the aircraft. The canard is a low-wing set up and the main wing is a high-wing setup. Of course, they can all change. At VTOL takeoff and landing, the front wing would rotate 90 degrees so the engine could point downward. During cruise the engine would rotate back to be horizontal. Since the canard could fully rotate, and it also carries and thrust component, I just don't think it fits the definition of the different canard types as described in the wiki. Since the rotation of the front wing could change the direction of 2/3 of the aircraft's thrust, there is no need to have any camber in its airfoil, right? And the only requirement of this wing section's aspect ratio is that its wing need to be stubby so there won't be much drag and countertorque when the front wing is rotating?
Edit: maybe I have made a wrong assumption, I should not arbitrarily set all of the engine to be the same thrust. I should set that these two engine at the front provides a thrust that is reasonable, that could ensure the balance of the aircraft during VTOL.


texts: FAR 91.215-- may an aircraft with no electrical system and no transponder overfly Wheeler AAF at 9500' MSL?

texts:
Here are some of the airspaces where FAR 91.215 requires aircraft to have transponders--

  (b) ...

  (2) All aircraft. In all airspace within 30 nautical miles of an
  airport listed in appendix D, section 1 of this part from the surface
  upward to 10,000 feet MSL;

  (3) Notwithstanding paragraph (b)(2) of this section, any aircraft
  which was not originally certificated with an engine-driven electrical
  system or which has not subsequently been certified with such a system
  installed, balloon or glider may conduct operations in the airspace
  within 30 nautical miles of an airport listed in appendix D, section 1
  of this part provided such operations are conducted -

  (i) Outside any Class A, Class B, or Class C airspace area; and

  (ii) Below the altitude of the ceiling of a Class B or Class C
  airspace area designated for an airport or 10,000 feet MSL, whichever
  is lower; and

Consider the airspace near Honolulu International Airport (now Daniel K Inouye International Airport), HNL/ PHNL.  (Link to sectional chart.)

May an aircraft with no engine-driven electrical system operate at 9500' MSL directly over Wheeler AAF (HHI/PHHI)?

This airspace is within one of the 30-nm Mode C veils described in FAR 91.215 (2).

The intent of the question is to ask whether the "Below the altitude of the ceiling of a Class B or Class C airspace area" clause of 91.215(3)(ii) applies only within the actual lateral boundaries of (i.e. within, above, or below) Class B or C airspace, or throughout the 30-nm circle.  Wheeler AAF is within the mode C veil for HNL, but beyond the actual lateral boundaries of any of the Class B airspace.  The ceiling of the Class B airspace at HNL is 9000' MSL.

See also related question FAR 91.215 (b)(3)(ii) -- transponders-- does the "or below 10,000' MSL" clause have any practical significance?


texts: Why was the TSR-2 literally burnt down even before its first official flight?

texts: The BAC TSR-2 was one of the aviation marvels of the time and the test flights had pretty good records. So why was it cancelled?


texts: Need some help with a seemingly simple question

texts: An aircraft flies from A to B, distance 155 nm, in 1 hour and 23 minutes. If there is a tailwind of 12 kts the TAS is?


texts:
Some Hobbs Meters uses master electricity switch to keep the track of time.

So what If an cheapskate Skylane pilot wants to fly without electricity to lessen rent?

Which main six instruments would keep working?
Would the engine fail? (There are both carburated engines
and fuel injected engines which complicates things a little bit)


texts: Does the ditching switch allow an A320 to float indefinitely?

texts:
I watched a documentary yesterday about the Hudson River ditching of US Airways Flight 1549. In the documentary, one of the investigators explained that the reason the water was entering so quickly was because the FO did not have time to hit the 'Ditching' switch the A320 is equipped with. This switch closes all vents etc. to prevent water from entering the cabin.

If an A320 or similar is ditched and the switch is activated in time, does that totally prevent water from filling the cabin (in a best-case scenario)? I'm thinking if one ditched in the Atlantic and had to wait for hours for help, would it be possible to stay afloat for so long?


texts: Flying in a helicopter with open doors: why don't people fall out?

texts:
This has been puzzling for quite a long time.

Every action movie or military documentary features helicopters with no door or with open doors and yet people inside look like they couldn't care less. Apparently they're not falling out...

Why is it so?


texts: How do I tell a Garmin 430 not to exit a hold?

texts:
Let's say that we're directly west of CATLI and have been cleared direct CATLI for the RNAV approach.  We load the approach into the GNS430 and proceed direct the fix.

After crossing CATLI outbound for the hold-in-lieu-of-procedure-turn, we realize that we want to stay in the hold for a few more turns.  How do I tell the 430 that I don't want it to sequence to ZAMGI upon arrival at CATLI?


texts: Is altitude information included in filed flight plan?

texts: When the dispatcher produces and files the flight plan for a scheduled flight with ATC, are the determined optimal cruise altitudes part of the flight plan, or does the flight plan only contain lateral route information?


texts: What is the piece that covers the top part of tires?

texts: I would like to know the name and the usefulness of this piece that covers the top of the tire of some planes, such as some Cessnas.


texts: What was the purpose of the "tail prop" on the Ilyushin Il-62 and why was it necessary?

texts: I read somewhere that the Ilyushin Il-62 had a "tail prop".  What was this device and why was it needed on this aircraft?


texts: What is in 'stealth paint' to reflect radar, and how does it work?

texts: What is in the 'stealth paint' that coats stealth bombers e.g B-2 spirit, and stealth aircraft, e.g SR-71, and how does it absorb/deflect radar?


texts: What are the regulations for crossing the Atlantic in a twin engine prop plane

texts:
Are there ETOPS like regulations for private planes?

If the plane has the range (4000km+), can it do it in one go?


texts: Why is Mode C helpful for ASDE-X systems?

texts:
Airports that operate an ASDE-X system require aircraft to operate transponders in mode C while moving on the surface.

While I understand the general purpose of operating the transponder to correlate with the other information ingested by the ASDE-X system, why is altitude (encoded in mode C) important for tracking surface movement?

Wouldn't mode A suffice?


texts: Does the DC-3 passenger airliner have slats?

texts:
The DC-3 is a very popular and widely used aircraft, yet has low speed tip stalling risks due
to the design of its wing, which at the time of its development represented the leading edge in drag reduction for larger and faster mono-wing aircraft in the 1930s.

Specifically, the swept and tapered wingtips, at high angles of attack, would stall first.

Did the original design, or later modifications, include slats to remedy this issue?
Is there any way to reduce this risk other than retractable slats?


texts: When may pilots leave the flight deck during flight?

texts: Are there regulations as to when commercial pilots may leave the flight deck during flight, i.e. due to physiological needs? Anytime when it is practical (obviously it would not be practical during take-off, approach and landing), or only during the cruise period (i.e. controlled resting only allowed in cruise)?


texts: During a takeoff emergency, is it safer to abort or continue the takeoff if either can be done within the available runway?

texts:
In a multi-engine airplane, if an engine failure occurs at the exact moment that a decision needs to be made to reject or continue the takeoff, and there is plenty of runway available to do either, which one is statistically safer?

A more technical way to ask the same question would be:  When there is sufficient runway available, is it better to artificially increase $V_1$ (via an assumed temperature takeoff or similar approved procedure) in order to stay on the runway longer in case an abort is required, or would it be better to leave $V_1$ at the lower speed and take any problems into the air?


texts: Flying coworkers with a commercial pilot's license (USA/FAA)

texts:
I will soon have my commercial pilot's license, and work full-time in a company and role unrelated to aviation. As a private pilot under FAA part 61.113b, I know that I can fly myself to conferences or sales meetings while having my employer reimburse me for the aircraft rental because the flight is only incidental to my employment.

My boss asked if my new CPL will allow me to take coworkers on such a trip, and I don't know how to answer him. It would be incidental to my employment and for a common purpose (i.e. I am also attending the same meeting), and there is no holding out since it would only be employees of the same company for a common purpose. I am also salaried, so there is no additional direct pay for the flight (just logging time). I'm not sure how to answer, and there are 3 scenarios to further complicate this (assume all aircraft have had 100-hr inspections):

I rent the plane and submit for reimbursement along with my other ordinary business expenses.
The company seeks out and rents the plane without my input.
The company rents the plane from an FBO, but after asking me for a recommendation on where to find one.

Which of these are permitted with a CPL? I'm 99% sure that #2 is completely fine, but can't find regulations for or against the other scenarios.


texts: Does the FAA issue multiple physical certificates for different aircraft categories and privileges?

texts:
If one holds a private pilot certificate in both airplanes and gliders, does the FAA issue two plastic cards that one would have to carry? What if one has commercial privileges in airplanes, but private in gliders?

What about being private in airplane, but sport in powered parachute? Some schools say that if one already has a private in airplane, then powered parachute at sport level would only be a logbook endorsement rather than a new piece of plastic. I was under the impression that logbook endorsements are generally things like the ability to fly a complex airplane, rather than being a sport level in a different category of aircraft.


texts: How can an airliner make up for time lost?

texts: If a plane has been delayed at the origin how does it make up for the lost time? Does the pilot need any special permission from ATC to increase the speed so that it can cover the lost time or has the pilot the power to make such kind of decisions?


texts: Did Concorde really fly above 55k feet as mentioned in this report?

texts: Here is a report of the last journey of Concorde from JFK-LHR, which mentions "The highest altitude we reached was 58000 feet." Is this height aerodynamically feasible to reach?


texts: Why are RC rotor blades different from helicopter blades?

texts:
Why do toy (RC) helicopters have curved flat surfaces and larger rotors on true helicopters have a solid aerofoil shape?

If the rotor was mechanically strong enough to lift the desired weight, is there any (aerodynamic) advantage to the solid aerofoil over the simpler curved surface?

Surely toy manufacturers could "close the bottom" of the rotor (equating to the aerofoil shape) even if it was hollow with negligible increase in weight.

I understand the Bernoulli effect does not necessarily apply to the RC rotors and it may be simply a Coanda effect but they do seem to lift well with just electric motors.

I have seen discussion that there is a "scale up" effect but why and if so at what size does the simple rotor start to fail... one foot, three feet, ten feet? Is there any data to indicate when the transition from this simpler design to a fully extruded solid rotor is required?


texts: Can the MH-60 helicopter fly without one or all of the stabilators?

texts:
The MH-60R helicopter has a horizontal Stabilator that consists of three subassemblies, RH Stabilator, LH Stabilator, and Center Stabilator.

Can the aircraft fly without the RH Stabilator?

Can the aircraft fly without the entire Stabilator?


texts: Does the Airbus A320 or Boeing 737 have better resolution screens in the cockpit?

texts:
I know this is kind of a specific question so if nobody knows it's fine. Does anybody know if the Airbus A320 or Boeing 737 has better resolution cockpit screens like PFD and ND? ( For the Airbus A320 I also mean the new screens like some A320 have more circular cockpit screens and the new ones are more square and look more defined

Here's the new screens, well it's not new but it's better

Here is the more circular screen


texts: What do the number at end of model numbers mean?

texts: When i see thing on the internet about aircrafts it often has a number at the end of the model number such as B737-300, what does the number after the dash mean?


texts:
Found this during a garden clearance. Have included a photo of serial number. Could you identify where this came from?

dimensions: width 115cm length 140cm.


texts: When Boeing designed the 737NG, what factors influenced the change in the flap system?

texts:
The early Boeing 737 models had wings with triple-slotted flaps that appeared to be derived from the 727. When the 737 was redesigned as the Next Generation series (dash 600 through 900), these flaps were dropped in favor of a double-slotted design.

Why did Boeing choose to make this change, and what were the trade offs? Did it impact performance? I had always been under the impression that early 737s were reasonably capable on shorter and rougher runways.


texts:
I see many questions regarding the unreliability of thrust reversers. Why are these components so faulty across all airplane models and manufacturers?

Is there a technical challenge to making the the thrust reversers as reliable as other aviation systems? Are the A380's electronic thrust reversers more reliable than the traditional mechanical or hydraulic reversers?


texts: What's this red cabin light indicator inside a Boeing 737?

texts:
What's this red light indicator inside the cabin, its flush with the sides of the plane. The exact location would be a couple of rows ahead of the overwing exit seats.

This picture was taken before take-off. Forgot to observe the light after take-off. This is not a flight-attendant call indicator.


texts: What are the pros/cons of all-moving rudder?

texts: All-moving flight control surface (stabilator instead of a stabilisator+elevator) are common on supersonic aircrafts but this is usually used for pitch control only. For rudder, this design (one all-moving piece instead of 2 separated pieces, the rear one being the one moving) is not common. The only example I think of is the SR-71. What are the reason for adopting this all-moving rudder on the SR-71? Why is it not spread? In short, what are the pros and cons of all moving control surface for yaw control?


texts:
I've read that the "F-16", without it being specified what version, uses the 1750A CPU, it is on the list here, although without a citation: https://en.wikipedia.org/wiki/MIL-STD-1750A

However, surely this can't be right for more modern F-16's?

I'm curious what CPU the F-16A, C, E, and IN uses.

Perhaps even the more modern F-16's still retain the 1750A for some "legacy" features, but have a more modern "front end" CPU to handle the more modern features?


texts: Is it possible to power a very small jet using batteries?

texts: I have read a lot of answers on batteries powering large commercial jets, and how it won't work. However, for a small jet like the Honda jet, would it be possible for it to be powered completely by batteries?


texts: What causes the "growl" of some large turbofans at takeoff thrust?

texts:
There are some (all?) large turbofans which emit a distinct "growl" (some people call it a "buzzsaw" sound) at takeoff thrust. What causes it? I've seen it explained (as in this question) as the fan blade tips going trans sonic, but it doesn't account for the pitch, or so I believe. A main fan has something like 20 or 30 blades, and must be spinning at several thousand RPM at takeoff power (maybe on the order of 4,000); a blade tip would then be passing a given fixed point at around 80,000 (or more) per minute or 1,300 (or more) per second.

The musical middle C is only around 260 Hz, so any blade noise should sound like a high-pitched whine, not a low-pitched growl. You can often hear "beat" sounds due to two or more engines running at almost the same speed, but the buzzsaw growl is distinctly different. So what causes that sound at that pitch?


texts: Does pumping fuel to each wingtip affect roll trim in a stabilized turn?

texts:
If an aircraft is stabilized in a constant-bank, constant rate turn with no sideslip, and then we pump 200 gallons of fuel from a fuselage tank to a tank on the tip of each wing, without changing the position of the ailerons or rudder, and without changing the aircraft CG, will we find that the aircraft tends to roll into the turn, roll out of the turn, or neither?

The intent of this question is that we get the aircraft fully stabilized in a coordinated turn at the original bank angle after pumping the fuel to the tips, and then we put the controls back in their original positions and see if the aircraft tends to roll.  This isn't meant to be a question about the effects of suddenly redistributing the mass and the way that this might possibly create a temporary yawing tendency due to yaw rotational inertia, like we see when a skater throws out their arms horizontally while spinning around.


texts: Do safety-critical avionics systems run Linux?

texts:
I have heard diverse things about this. Some people claim that running Linux on safety-critical avionics systems is a very bad idea. On the other hand some people (who are rather unfamiliar with avionics) said this is not true.

So I would like to know, do aircraft nowadays run on a Linux distribution?
Is it a good idea to incorporate Linux in aircraft? If not, why?


texts: Is there a standard install direction of the abradable shroud honeycomb on a CF6-80c2 engine?

texts:
Is there a standard install direction of the honeycomb cells on the Fan Forward case on the CF6-80C2 abradable shroud section?

I have seen engines that the honeycomb cells run point to point front to back. I have seen engines where the cells run point to point in the direction of the circumference of the the abradable material for the Fan blades. I have searched the manuals and I cannot find where the orientation of the honeycomb is specified.

Any repairs are understandably performed with the same orientation.  I am wondering is there a MFG standard?


texts: How does area ruling cancel drag from bodies that are neither upstream nor downstream of each other?

texts:
This might sound like a silly question, but it's one I've had for quite some time.

(source)
How is having that.....waist okay? I mean, the more complicated your body is, the more drag it creates, right? In any case, how does the WING affect this waist? How is it supposed to cancel out the drag from the wing, when it is neither upstream or downstream of the airflow affecting and affected by the wing?
Then again, let's look at the more modern inplementation.

(source)
Again, there are flap track fairings visible. These are supposed to be doing area ruling of the seemingly clean fuselage and wing by adding frontal area(?).
And again, they are neither directly upstream nor downstream of any other part of the airplane.
Can anyone explain how these seemingly irrelevant features in aircraft can reduce drag?