texts: Is the maximum power the Merlin 61 reciprocating engine occuring at its maximum RPM?

texts:
Looking at the stats breakdown on Wikipedia here for the Merlin 61 series reciprocating engines used in Spitfire planes, I noticed that maximum horsepower is given at approximately 3000 RPM. But AirPages has what looks like a manual here that lists the maximum RPM as 3000.

Are they simply stating that the same thing: that torque starts to fall off at 3000 RPM? Or are they saying that the engine is just physically incapably of spinning faster than 3000 RPM (seems unlikely)?

In the case of the first one, what is the (approximate) redline for one of these engines?


texts: How does a diffuser (in ground effect) accelerate the air in front of it?

texts:
A diffuser reduces speed and increases pressure, so how does a diffuser accelerate air in front of it if we have an adverse pressure gradient situation?
Wouldn't be better that we put the lower pressure (instead of higher) on end which will "pull"/accelerate air in front of it?
Example of F1 diffuser in ground effect:


texts: Is Part 91 Instrument currency for SIC similar to Part 135 requirements?

texts: Part 135 instrument currency in a jet aircraft requiring two pilots, requires both pilots to be instrument current. But how about the same situation for a Part 91 flight? Does the SIC need to have his 6 approaches with tracking, intercepting, holding etc... in the last 6 months?


texts: Is the in flight emergency manual of a Boeing 737 Max 8 available to read online?

texts: I frequently read about pilots going through manuals/checklists/procedures  in an emergency situation in an airliner while in flight. Is there an online resource where the public can actually read it, for e.g. for Boeing 737 Max 8?


texts: What are the unique shapes of the weapons control switches in a F-14?

texts:
In his answer to the question Muscle memory for weapons systems? Michael Hall mentioned "'blind fold cockpit checks'... (learning to) locate certain switches by feel, reinforcing muscle memory to both locate them and identify them by their often unique shape."

These illustrations of F-14 control panels

F-14 weapons control panels, and

F-14 control panel

show the switchology (hey, I learned a new word) of the aircraft.

I don't see any distinct differences in the shapes in these diagrams.  What at the different shapes used in an F-14 to distinguish switches by feel?  Are there any other clues to help in the assistance of locating by feel?

If information about the shapes of switches (or other means to identify by feel) in other combat aircraft is available as an alternative, that would suffice to answer my question.


texts: Is it possible to get permission for a GA flight to land at Reagan National Airport?

texts:
If it is possible for a General Aviation flight to land at Reagan National Airport, what would you have to do?

If it's not, what kind of security clearance do commercial carriers and their pilots have to go though in order to land there?


texts: Does the aerodynamic center always have to lie on the chord line?

texts:
A lot of resources online state that the aerodynamic center is the "point on the body of an airfoil with respect to which the moment coefficient does not change with angle of attack." However, does this necessarily imply that the aerodynamic center must lie on the chord line? Of course, we can resort to thin airfoil theory and prove that it lies on the chord line, but what about for highly cambered airfoils?

This answer (Why does the aerodynamic center exist?) explains the existence of the AC, but resorts to inviscid, incompressible, thin airfoil assumptions. What about in general though? So, is the aerodynamic center present on the chord line in general for all flows? If not, when does it deviate from chord line and why?


texts: Do FAA regulations keep aircraft away from 18,000 feet MSL to avoid conflict with FL190?

texts: In the US, is there any FAA Regulation that keeps all aircraft away from 18,000 feet MSL… Since theoretically, FL190 could be lower than 18,000 feet MSL, and create all kinds of confusion with keeping safe aircraft separation?


texts: Why are some windows in cockpits made openable?

texts: Why do aircraft allow sliding / opening windows in cockpits? What purpose does it serve, and why the same can't be done for passenger windows as well?


texts:
For all runways I've known or seen, they're numbered on both sides, with the number on the opposite direction differ by 18.

Are there runways that are numbered only on one side? I.e. due to certain constrains, the runway can only be used in one direction and never the other.

EDIT: I'm looking for runways where the aircraft is always pointing at the same direction. E.g. only runway 9 is available, you can never use runway 27 for whatever reason.

A runway that is blocked on one end will still have two numbers, since you'd land at one direction and takeoff the other.


texts:
Why is it so hard to make large aircrafts?

Boeing stopped after the 747. They haven't made a larger plane ever since.

Airbus A380 took a long time for it to be designed.

  In June 1994, Airbus announced its plan to develop its own very large airliner, designated as A3XX. Airbus considered several designs, including an unusual side-by-side combination of two fuselages from its A340, the largest Airbus jet at the time.

From 1994 to 2005, nearly 11 years.

I'm not talking about the market feasibility or the cost here, but more in terms of physics and aerodynamics. We already have so many different models of airplanes. If we have working models of airplanes, how about simply scaling them? Would it work? If not, why not?

It would be great if reliable sources from the Boing 747 or the Airbus A380 development programs could be given.


texts: How can I recognize Taylorcraft BCS-12D-4-85?

texts:
I'm perfecting my logbook and can't name the subtype of the aircraft I've flown. Some directories says it was built in 1946 and is a BCS-12D on floats. Others say it is a BCS-12D-4-85 which according to Wikipedia was built in 1949.

Is there a way to know which aircraft I was training in?


texts: What is the purpose of long endurance test flights?

texts:
Well known is the last long endurance test flight by a Boeing B787-8, which drew its shape in the air for 18 hours while on a long endurance test flight: https://www.wired.com/story/boeing-787-8-drawing-test-flight/.

What exactly is the purpose of these long endurance test flights? What is tested, what shall be proven? - surely not that the aircraft can actually stay in the air that long, because that test flight happened long after the introduction of this type into the market...

On a side not, does every commercial airline type have to undergo such an endurance test flight?


texts: How can I progress from tactical aircraft mechanic in the air force to an airline?

texts: I am currently 17 years old and next year I will be graduating from  high school. My plan is to go to the Air force and become a Tactical Aircraft Mechanic. Obviously I am going to go through BMT and then Tech school. But after I learn that career I want to work at an Airline. How does that work specifically?


texts: How are "Local Flights" defined in European regulations?

texts:
Looking at some Greek aerodrome information charts, I discovered that there are airports with the designation "Local flights not permitted". I speculate this is because the areas are near sensitive/military installations.
My question is: How is a "local flight" defined?

Is it a flight where the departure as well as arrival point is the airport in question?
Is it a request for touch & go?
Is it a flight around the airport area, beyond what is required for departure/landing (though I wonder how easy is that to define, particularly in case of e.g. meteorological conditions, such as local clouds)?
All of the above? Something else?

FWIW, I noticed this looking at older charts (suitable only for simulation purposes), so I don't know if this reflects up-to-date information.


texts:
In reading about various theories of what happened to flight MH370, there's a lot of discussion about it possibly crashing into the ocean, breaking up, and pieces of the aircraft floating hundreds of miles away.

Is it generally expected that large pieces of an aircraft will float fairly well? E.g. in the linked article, there's a picture of 4 guys carrying what looks like a big chunk of wing. How did that float?

My assumption would have been that that chunk was hollow aluminum fuselage, maybe with some electronics and hydraulics inside, and maybe a portion of a gas tank. I don't get how it would float unless it got lucky and a subsection of gas tank that was empty and did not get pierced during the breakup landed with its inlet/outlet pointing up.

Thanks.


texts: Is an eclipse considered 'night' for regulatory purposes?

texts:
A partial or total eclipse is as dark as twilight, but only for a short period. Does it count as night flying for regulatory purposes?

I'm looking for a UK answer, but information about the US is interesting too.


texts: What is the FAA definition of solo flight?

texts: If I'm a student pilot (for commercial), and I flew for pleasure with friends one night, do I log those hours as solo? Does solo mean, only pilot in the aircraft? Or does it literally mean only person?


texts: Price of a light weight aircraft that can be owned

texts:
I am just an aviation enthusiast and wanted to be a pilot someday..
I just wanted to be able to buy one light aircraft someday..

Can you tell me what would be the price of a light weight aircraft that can be bought?
And also the maintenance charges?
Thank you


texts: What exactly rotates along the lateral axis? Is 'rotate' mathematically correct?

texts:
Researching the etymology of 'rotate' (that OED lacks!), I chanced on Anas Maaz's Quora answer:

  What many does not know is 'rotate' is just not a fancy word, but it involves a real physical rotation. When Rotation speed (Vr) is reached, the pilot pulls the control column which deflects the horizontal stabilizer, causing a rotation along the lateral axis of the airplane lifting up the nose wheel.

Am I correct that Maaz's referring to the 'lateral axis' in the diagram beneath?

Even if yes, what exactly ROTATES? How does the lateral axis ROTATE?

Imagine the wing on the y-axis and time on the x-axis, like the graph beneath.
I don't think it's correct mathematically to state that an axis rotates, when it's the function that moves up as time passes?


texts: What are the difficulties of landing on an upslope runway?

texts:
On runway like the one in Courchevel Altiport, how difficult is it to land? what is diffirent in the aircraft landing configuration when landing on an upslope runway vs normal runway?

EDIT:

Thanks for the answers guys, I didn't know that the airport had a level "touch down" point. still I am curious what should a pilot do (regarding air speed, pitch, flaps ...) if the runway itself was 10% upward (no level parts)... would the plane be in a "climbing-like" configuration? what about speed?


texts: Are "Tally-ho" and "no joy" acceptable ATC terms for civil operations?

texts: I keep meaning to ask this question. I heard "Tally-ho" used for the first time by a pilot on Liveatc.net. I know these are pretty standard phrases in military aviation but I wondered if civil pilots use them. Are they acceptable under either FAA or ICAO standards? If not, what's the likelihood a controller will know what you mean?


texts: How can I find aircraft and airline listing data for planespotting?

texts: I vaguely remember when younger a spotter I knew having a book listing all airlines and all aircrafts within the airline at time of print. Is this data available now in book or online format? I'm looking to get back into spotting.


texts: When flying a circling approach, is it permitted to begin the visual circling segment prior to the final approach fix?

texts:
If it were a beautiful sunny VFR day and you were cleared for a circling approach, can you begin the circle prior to the final approach fix/circling DH in order to maneuver visually to land?
Here are two examples of situations where it would be very useful, and both are real life clearances that I have gotten multiple times:

Example 1 - KASE
Clearance:

N1234, Cleared for the VOR/DME-C approach, cleared to land runway 15

If you follow the step downs until the final approach fix (ZIGBU) you will be at 2,983 ft. above the runway (10,820 ft. MSL) with 2.9 miles to go (9.61 degree descent angle).  To put this in perspective, on a normal 3 degree descent, you should be at 870 ft. above the runway so are over 2,000 ft. high on less than a 3 mile final.
Could you begin the circle early and descend while visually avoiding any obstacles prior to the step-down fixes?  Say cross ALLIX at 11,000 ft. and ZIGBU at 9,000 ft. (assuming that this cleared all obstacles)? Keep in mind that this is a circling approach so we will be operating below the MDA visually at some point on final anyway.
If not, then it would be nearly impossible to land straight-in while flying most jets, and yet I have never seen anyone do a 360 or a similar maneuver while on final here (and who would want to do that in the valley anyway??).

Example 2 - KTEB
Clearance:

N1234, Cleared for the ILS Runway 6 Circle Runway 1 Approach, cleared to land runway 1

If I fly the ILS (localizer and glideslope) until reaching circling minimums, especially in a category C or D airplane and with this runway layout, it will take a lot of room to turn right for a base leg to runway 1 and then turn back left to intercept final and lose the required altitude.
Could you start the circle a little sooner by making the right turn early (prior to DH, but still within the protected circling area) in order to intercept the extended final for runway 1?


texts: How do the uninterrupted and interrupted flaps compare?

texts:
(wikimedia.org) Airbus A350.

There aren't many wide-bodies out there. Whether it's Douglas, Boeing, or Ilyushin, they all have the high-speed aileron interrupting the flaps. Whereas Airbus uses uninterrupted flaps in all their fly-by-wire aircraft with the two ailerons outboard.

After Boeing has adopted fly-by-wire, it is still sticking with its flaps design in the 777 and 787. I'm aware Boeing now uses flaperons, but as the image below shows, its deflection is not all the way to avoid the jet blast, but how does Airbus get away with it?

For the uninterrupted, here are some reasons I can think of but can't link:

Smaller deflection for takeoff and landing is better for noise and fuel, but may incur a weight penalty because the flaps are in the jet blast and need to be built stronger.
A smaller overall wing is better for weight reduction, but worse for wing loading.

(wikimedia.org) Boeing 777.

Why did Airbus choose this design (apart from its A300/A310)? They must have a good reason. Equally for Boeing for not using them with its FBW aircraft. Unless it doesn't matter, or a patent is involved.

Related:

Why do similar Airbus and Boeing aircraft use different flap and slat mechanisms? Asks about the number of slots, slat types, etc.
When Boeing designed the 737NG, what factors influenced the change in the flap system? Asks about the 737 Original, here the engine was the split:

(Source)


texts: Could a single engine pilot land a passenger jet? (from Airplane)

texts:
I'm assuming that almost everyone on this website has seen the movie Airplane at least a few times...

Last time I was watching it I was wondering how plausible the actual act of having a single engine prop pilot, with a lot of training (maybe comparable to a modern day aerobatic pilot), land a quad engine passenger jet?


texts: Where can I find the best site to learn aircraft design on a small scale?

texts:
I am undergraduate student still trying to figure out a lot about Aerodynamics and aircraft design. I am learning how to design rc planes.

So the thing I know the weight of my plane which is between 700 gm to 1000 gm and velocity which is 13 m/s.

I just know the basics that is the lift formula and other fundamentals. I want to know how to design a nice fuselage for my plane and also how to keep balance in my plane. I seriously need help and also there are courses where you learn all this, but they ask for heavy cash.


texts:
The westerly index, appears in a CPL syllabus but I can't find much info on it, I assume it is a measure of how systems move from west to east in the southern hemisphere.
How exactly is it calculated, and what is it's purpose and significance for aviation?


texts:
Assuming the larger (receiving) AC has holding mounts and the smaller AC can slowly approach without contacting the tail. Possible example, land a cesna on the back of a C130
Would the weight of the smaller aircraft be compensated by the lift generated from it's wings?


texts: Why does manifold pressure increase with power?

texts:
Whilst writing an answer to this question, I remembered something I don't really understand.

The partial vacuum in the inlet manifold is caused by the piston descending with the inlet valve open during the "suck" phase of the Otto cycle.  It is this vacuum that causes fuel to be pushed into the intake, the greater the vacuum, the greater the fuel added to the inlet charge and the greater the power.

Since the needle valve is on the manifold side of the throttle butterfly along with the input to the MAP gauge, why does the manifold pressure increase with power?  I would have thought more power, more "suck", lower pressure; more pressure, less "suck", less fuel.

I'm obviously wrong since that's not how it works but why?

The answers to this question get close but I'm still missing something (and I'm sure will soon be embarrassed by the obviousness of the answer).


texts: Can thrust reversers possibly collapse due to strong crosswinds?

texts:
I recently watched a YouTube video titled "Dangerous Crosswind Landings during a Storm at Düsseldorftitled" and witnessed at the 2:06 mark, a twin engine commercial jet aircraft landing and noticed only one thrust reverser was deployed.

I am looking for a knowledgeable answer, asking if this was a malfunction.


texts: Why do we undershoot/overshoot with a compass turn?

texts: In the southern hemisphere you would undershoot when turning towards a southerly heading and overshoot towards a northerly heading, and the opposite in the northern hemisphere. Why is this?


texts: Could an explosive decompression trigger the smoke detectors?

texts:
In a commercial airliner at FL370, in the event of rapid (explosive) decompression, will the cabin air fog? And can that fog trip smoke detectors?

Pressurized aircraft can have a cabin altitude of 6,000 ft, or so. What is the differential pressure at 37,000 ft? Again, would an explosive decompression of 8-9 PSI, fog the interior environment?


texts: Are there any single-pilot aircraft certified in the Part 23 Commuter category?

texts:
Is it possible to certify an aircraft under FAR 23 Commuter Category with single pilot ops only? Like, there is just one seat in the cockpit and up to 19 passengers.
Does anyone know of such an aircraft flying?


texts: What is the difference between placing wheel chocks on the outer wheels as opposed to the inner wheels of the main landing gear?

texts:
Recently I am aware of a change made to the IATA Ground Operations Manual (IGOM) in regards to the position of the wheel chock on the main landing gear.

Is there a justification for why one method is preferred or is safer than the other?


texts: What is the approximate price of a McDonnell Douglas MD-80 series aircraft?

texts: Does anyone know the approximate price of an MD-83/87 aircraft manufactured between 1990 and 2000?


texts: What is the relation between an airplane's altitude and the drag it is experiencing?

texts:
The Reynolds-Number $Re$ is defined as $Re = \frac{c \cdot L \cdot \rho}{\mu} = \frac{c \cdot L}{\nu}$, with

the velocity $c~\left[ \frac{m}{s} \right]$,
the reference length $L~\left[ m \right]$,
the density $\rho~\left[ \frac{kg}{m^3} \right]$

$\rho = \frac{p}{R \cdot T}$ for ideal gases
pressure $p~\left[ Pa \right] = \left[ \frac{kg}{m \cdot s^2} \right]$
temperature $T~\left[ K \right]$
ideal gas constant $R~\left[ \frac{J}{kg \cdot K} \right] = \left[ \frac{m^2}{K \cdot s^2} \right]$

the dynamic viscosity $\mu~\left[ \frac{kg}{m \cdot s} \right]$ and
the kinematic viscosity $\nu~\left[ \frac{m^2}{s} \right]$, $\nu = \frac{\mu}{\rho}$.

From my understanding, drag increases with decreasing Reynolds-Numbers. Hence, drag increases with an increasing kinematic viscosity (see e.g. this book):

Relation between altitude and kinematic viscosity according to the ISA (International Standard Atmosphere)

With an increasing altitude, the density of the air decreases.
The dynamic viscosity decreases with an increasing altitude of up to $11'000~m$, then stays constant to $25'000~m$ and increases from an altitude of more than $25'000~m$.
This is based on Sutherland's Formula for ideal gases, which in turn relies on the air temperature.
According to ISA, air temperature decreases with an increasing altitude of up to $11'000~m$, then stays constant to $25'000~m$ and increases from an altitude of more than $25'000~m$.
Dividing $\mu$ by $\rho$, one can see that the kinematic viscosity increases with an increasing altitude.
See for example here or here for precise data.

In summary, the Reynolds-Number decreases with an increasing altitude, which means that drag increases with an increasing altitude - assuming velocity and reference length are constant.

Does an airplane really experience more drag, the higher its flying altitude is, assuming otherwise constant parameters?

When researching for this question, one often stumbles across the statement that drag decreases with increasing altitude due to the decreasing density. However, no one seems to take the kinematic density into account.
Are there trustworthy charts available indicating drag over altitude?


texts: Are there FAA approved infrared night vision devices we could use in case of engine failure at night in IFR conditions?

texts:
Terrible situation.  Your single engine on your general aviation aircraft fails.  You are flying at night, no airports nearby enough to land at and patchy fog causing Instrument Meteorological conditions near ground level.

You pitch the plane for maximum glide, squawk the emergency 7700 code on the transponder, declare an emergency, and try desperately to see an opening in the fog for a field or road to attempt an emergency landing but can't see anything as it is pitch black and foggy.  You follow the emergency procedure to try and get engine started.  In order to not harm civilians on the ground who had no role to play in your mishap, you ask for vectors from ATC to a shallow body of water.  ATC vectors you to a nearby small lake for you to ditch the plane.

Is there an FAA approved infrared night vision device that would have allowed me to see through the ground fog and locate a suitable landing site?  If FAA approved model does not exist, what is the minimum sensitivity and resolution that would do the job?


texts: If the the body and it's wing is mostly covered with solar panels and flies with electric motors, is it possible for that aircraft to fly?

texts:
First before I say anything else, this is indeed a stupid question.
It would be most likely heavy, bulky, and expensive.

But theoretically, is it possible to fly with only Solar energy?

What does it take to accomplish such task? The total cost? Probable shape and size? The power required to lift off such a stupid aircraft?

What does it take to lift off with a single average man piloting the solar-powered aircraft? Without a man?

If you did calculate the amount of power needed, for both lifting a man and not lifting anything but itself, what else could you used that energy for?


texts: Found this old pic of an aircraft that used to service the north. Was wondering if anyone could identify, or had registration information. It would have been in service sometime between 1950-1970.


texts: Do any airlines have Braille emergency checklists?

texts:
In reading the report into the crash of UPS Flight 6, I noticed that one of the items of feedback from pilots in a simulated inflight-fire scenario utilising a smoke-filled simulator was (page 287 of the report):

  In the thickest smoke, only Braille will help. What bigger font does to you, if there is any "break" in the smoke, it allows you to see more letters (group), therefore part of words. From that you can deduct what the action on the checklist is for the next step.

(Emphasis added.)

Which makes sense, as Braille, unlike most scripts, is read by touch rather than by sight, and is, thus, unaffected by limited or nonexistent cockpit visibility, while visual scripts, even with large, simple glyphs, have their legibility severely impaired by a smoky cockpit (in dense smoke, the pilot(s) essentially have to wait to do anything until the smoke momentarily lifts), and are completely useless in a zero-visibility environment.

With this in mind, do any airlines (passenger and/or cargo) have Braille checklists for use in situations of severely degraded cockpit visibility (such as a cockpit filled to the brim with dense black smoke)?


texts: Where can I find pictures of "endplate"?

texts:
Where can it possible to find pictures or drawings of "endplate"? (for "winglet" is much easier, but not endplate)

I'm asking what's written above, after I read the following text from Raymer and I need a better comprehension of it.

  The wing aspect ratio "$A$" is the geometric aspect ratio of the
  complete reference planform. the effective aspect ratio will be
  increased by wing endplates or winglets

  Endplate: $A_{effective} = A(1+1.9\frac{h}{b})$ - (12.10)   where $h$ = endplate height

  Winglet: $A_{effective} = \approx 1.2A$  -     (12.11)

  These effective aspect ratios should also be used in the induced drag
  calculations below. note that Eq. (12.11) for winglets is a crude
  approximation based upon limited data for wings of moderate aspect
  ratio

......................

  The extra drag due to non-elliptical lift distribution and the flow
  separation can be accounted for using e, the "Oswald span efficiency
  factor". This effectively reduces the aspect ratio, producing the
  following equation for $K$

  $K=\frac{1}{πAe}$ (12.48)

  If the wing has end-plates or winglets, the effective aspect ratio
  from Eq. (12.10) or (12.11) should be used in Eq. (12.48)

(Source: Daniel P. Raymer "Aircraft design . A conceptual approach" , Chapter 12 Aerodynamics)


texts: Is platinum present in a combustion chamber?

texts: Platinum group of metals (PGM) are very resistant to extreme heat. Why is platinum never mentioned in aerospace world? Is this a top secret?


texts: What should I expect to happen when I get on a skydiving flight

texts:
I am schedule to go on a short flight (skydive)* on a Cessna 208B Grand Caravan during an international visit to some friends. I found the serial number of the flight, here is it's record.

Since privately owned aircraft within skydiving community are known not to be maintained as well as commercial operations and sometimes these pilots have very little flying hours, is there anything I as a passenger can do to improve the safety of the flight? For example, what pre-flight checks should the pilot make before taking-off?

Note* Related to this question.


texts: Why do you need airplane mode on a device for a plane trip?

texts:
I'm about to take a plane trip to my dads house but I'm just curious why you must have airplane mode on?

I'm no aviation master here, just looking for information.


texts: Why do many aircraft have both all-moving tailplanes and elevators?

texts:
Many aircraft - particularly large commercial airliners - have both an all-moving tailplane (horizontal stabiliser) and elevators. (They also have a small third moving element on the trailing edge of the elevators too.)
As far as I can tell, all these surfaces do exactly the same thing, ie cause a change a pitch. Indeed this answer confirms that both stabiliser and elevators have the same effect, although hints there may be differences at transsonic speeds, something that doesn't apply to most airliners.
I understand trim is concern, but ultimately you're just trying to point the nose up or down. Especially with computers calculating optimum angles, having two control surfaces, which may counteract each other, seems to add a lot of complexity.
Of course there must be some advantage to having both, I'd like to know what that is?
 737 empennage (source)


texts: Why does the US use two types of aerial refueling?

texts:
There are two main types of aerial refueling, the boom and the drogue. The US uses both, while most other countries use just the drogue.

How are they different and why does the US use both?


texts: Assuming I'm rich, take a PP course and buy a Boeing 737 or A320. Could I fly these planes for non-commercial purposes?


texts: Why do the A220 cockpit seats have a cutout?

texts:
Why do cockpit seats on the A220 have a cutout on the bottom cushion? The answers to Aircraft pilot's seats: what is the notch for? explain that these cutouts allow for easier maneuverability of the yoke. However, this A220 cockpit has no yoke. Why does this cockpit have the cutout?

(source: thepointsguy.com)


texts: Why is indicated airspeed rather than ground speed used during the takeoff roll?

texts:
My instructor asked me this question during my lesson and I couldn't come up with any answers. He asked why do I need to look at the indicated airspeed rather than ground speed when in takeoff roll or as soon as we touchdown?

It would be great if you could give me the reference to back it up.


texts: Can I get a Private Pilot's License if I have controllable ADD and just send a waiver to my doctor?

texts: Hello I am a fan of aviation and would love to be a private pilot, but I have ADD that is controllable. I can control my ADD and I'm cancelling my medications. Can I get a medical certificate if I just send a waiver from my doctor to the AME or FAA? Thanks for the help


texts: What criteria does ATC apply to determine if an aircraft is established on the localizer if the pilot does not report it?

texts: How close in time or distance will ATC let a pilot fly to the localizer, before cancelling the approach clearance, where the pilot has not reported being established? Is it the controller's call when to cancel the clearance?


texts: Does an IFR flight at night in VMC count as “night VFR conditions” (FAR 61.129)?

texts: FAR 61.129 several times uses the phrase “night VFR conditions.” Does this mean strictly flights conducted under VFR at night, or does it include night flights conducted under IFR but in VMC?


texts: How precise and how accurate are typical altimeters these days? That is, if two planes are flying (side-by-side, very near each other), and both altimeters show the same Flight Level, what is the maximum vertical difference in actual altitude you would expect to see between them? (I.e. is it on the order of a few meters, a few tens of meters, etc?) Is there any legal standard for precision/accuracy of the altimeter that must be met (let's say in the US)?


texts: Why does the static pressure inside the cockpit vary from outside static pressure?

texts: When the static ports are blocked, pilots use the alternative static soure and it measures the static pressure inside the cockpit. And it is said that the static pressure inside is lower than the outside static pressure. I wonder why does this happen? Because you know cockpit is blocked from outside and how does the venturi effect applied inside the cockpit and static pressure inside?


texts: Janes aircraft recognition guide has a picture of this plane on the Lear 35 page. Does it have missiles on it or is this some special modification?


texts: Where can I get a picture of a specific aircraft by registration?

texts:
I'm actually building a website where I want to display pictures of a specific aircraft. So I have the registration and I would like to show a picture next to each registration. For example I have the registration: A7-BCW

I want to get the picture in a way like this:

website.com/a7-bcw.jpg

Is there any site where I can do this and where I'm allowed to use the pictures for my site (watermarks are OK and I would also display the copyright information)? Of course there is no site where I can look up every aircraft around the world, I just need it for the common airlines like Qatar, Emirates, Singapore Airlines, Delta, United and so on.


texts: Can an airliner be refueled while the APU is running?

texts:
Race cars can be refueled while the engine is running. I assume this is a dangerous task done by highly specialised technicians.

If ground support is not available, an airliner may keep the APU running to be able to provide power to restart the engines.

If ground support is not available and refuel is needed, can an airliner refuel while the APU is running (technically and legally)?

If the question is too broad, it can be narrowed to best sellers (B737 and A320 families).


texts: 91 year old father allowed to fly a plane again?

texts: My 91 year old father got his private pilots license over 60 years ago. He has not flown an airplane for 35 years and is saying that he can go buy his own airplane, again, and fly it tomorrow legally. He says that there is no one that checks for credentials such as up to date medical. He is 91 years old and thinks he can hop into a plane and pick up where he left off 35 years ago legally. Is this true? If so, very scary to think a 91 year old, who thinks he is just as good of a pilot as he was 40 years ago, could get away with flying a plane without anyone checking.


texts: Why pilots would leave the cockpit in a short flight?

texts:
I've occasionally read about pilots being locked out of the cockpit in flight, and was wondering:

Why might a pilot leave the cockpit during a short flight (1-2 hours)?


texts: Can you report a crash landing on an emergency frequency even if you are not at the airport?

texts: You see a crash landing near the airport but you're in a car, no other planes have reported the status of the plane, and Approach can no longer contact the plane. Can you report the crash on an emergency or approach frequency to the tower?


texts: When does ATC contact the pilot for a frequency change?

texts:
Usually, when the aircraft enters a new flight information region for example, ATC will ask the pilot to enter a new frequency. I'm curious about when they do. Is there a rule about it (in an IFR situation)? I assume it may be different between EASA and FAA regulations.

Thank you.


texts: What is the significance of the V1 ground roll of an aircraft?

texts: What is the significance of a V1 ground roll of an aircraft trying to take off? Why is minimum ground roll is measured in feet? What is the significance of VR (which is greater than V1 but less than V2)?


texts: What are FARs & where can I find them? What is FAR 23, 25, 135, etc?

texts:
The FARs (or Federal Aviation Regulations) are the regulations imposed by the FAA on aviation within the United States.

Many questions make reference to FAR 23, or FAR 91 etc. What are each of these? Where can one lookup the text?


texts: GARMIN GTS 855, can i changing the Altitude Display Mode from ARINC 429 command?

texts:
I have  GTS 855 without Garmin screen for control. I have my own screen that connect to the TCAS(GTS 855) via ARINC 429.
It's possible to changing the  Altitude Display Mode via ARINC 429 command?
Which label I need to send to the TCAS to change the altitude display mode?


texts: When should I start turning in this circling approach?

texts:
I've been practicing circling approaches in Homestead General Aviation Airport in Homestead, Florida (X51). I performed the RNAV (GPS) RWY 10 approach with circling minimums.

My questions are:

a) For example if the active runway is Runway 18, then how exactly is the circling procedure performed? Should I start circling after crossing the MAP (XAGUH), or before?

b) And if the active runway would be 36, then the circling procedure would be to enter a downwind, then a base and then a final. Until when should I maintain the Circling MDA?


texts: What is the longest range single-pilot certified (FAA and/or EASA) business jet?

texts:
I suspect the single-pilot business jet with the longest range is the SyberJet SJ30x:

NBAA IFR Range with 100 nm Alternate
M 0.76 (1 pilot + 2 passengers; passenger/pilot at 90 kg each)
2,575 nmi (4,769 km).

But I am not sure; also, there are many negative reviews regarding SyberJet company and its aircraft of which, by the way, only a dozen have been produced for now. Are there any single-pilot certified jet with longer range in comparison with SyberJet SJ30x?


texts: Do pilots of commercial aircraft have ready access to a map or data showing nearest airports in case of a need to make an emergency landing?

texts: As a passenger I often wonder that if a pilot had to make an emergency landing, do they have access to live information to direct them to the nearest airport or is this something that they have to rely on from air-traffic controllers?  I'm thinking that seconds could mean the difference between life and death and having information as such on-board could be a life saver, rather than rely on others to figure out where to go during a crisis.


texts: What is the significance of Slip-Skid Indicator in PFD?

texts:
Slip Skid Indicator as depicted in the picture below;

What's the significance of Slip Skid Indicator?

How Slip Skid Indicator is used in flying the aircraft?

What are other performance/operations needs to be taken care while this exceeds its normal bound?

Primary flight display with Slip Skid Indicator, Source - www.aboutflight.com


texts: Is it the tower's purview to recall an aircraft from the runway for loading the wrong cargo?

texts:
On August 17, Ryanair flight FR 11 entered the runway after already being delayed for 1.5 hours, only to exit at the first available opportunity. After being jokingly welcomed to Stansted from where we had very nearly departed, we proceeded to wait for at least 1.5 hours more while the wrong cargo was being unloaded to make way for the correct one.

The crew told us the delay was due to having loaded the wrong cargo, and made it very clear to us that this wasn't their fault, which I have no reason to doubt. The pilot made it sound like the tower told them to abort. We were already on the runway and turned back at the very last minute.

My question is this: Does the tower have the authority to tell an aircraft to abort take-off for having loaded the wrong cargo?

My impression is that the tower is a traffic cop and safety officer rolled into one, and operational questions such as which plane does this cargo belong are outside their normal range of concerns.


texts: 61 vs 141: What's better for future US ATP?

texts: The pros and cons of each are all over the internet. Price and flexibility, which of the two routes looks better when applying for an airline regional or legacy, does it matter? More importantly which better prepares you?


texts: If airliners and commercial planes have turbulence, can helicopters have turbulence?

texts: I was watching a video of an V 22 (Osprey) taking off and it had that white cloudy stuff that looked like turbulence around the propellers. Can helicopters have turbulence too? I know an osprey is not a full helicopter nor airplane but it has some features of a helicopter.


texts:
Let's take a look to itinerary of a flight from Dubai to Tokyo taken here

And from Tokyo to Dubai

It's the same airline.

One more example. Here is the route of flight from Istanbul to Tokyo

And from Tokyo to Istanbul

Can somebody explain why return route is so different flying from East to West?


texts: How exactly is the 51% rule applied for amateur-built aircraft?

texts: I understand that for an amateur-built that you are required to build at least 51% of the aircraft yourself, but how can there be kits which appear practically completed, just some quick assembly jobs? Could someone explain how this 51% rule works, and what is this percentage based on?


texts: Can I become a pilot if I am under treatment for Attention Deficit Disorder?

texts:
I know that before you even begin training in flight school, you are required to get a physical examination from a doctor to determine if you are fit to fly. Online articles stressed the importance of being completely honest with the doctor about any existing conditions.

I was just recently diagnosed with ADD (or rather, I described my issues to my regular physician and simply started receiving medication to treat it) and this is something I would naturally disclose at the physical examination.

Does FAA disqualify someone from getting their pilot's license on the basis of ADD?

I take medication for this once a day and it resolves any issues I face from it.


texts: Why does flying inverted in a jet trainer starve the engine of fuel when there's a pump?

texts:
Such planes have an engine-driven fuel pump. If the pump isn't strong enough, wouldn't suction feeding assist?

How does a modern fighter jet / aerobatic plane overcome this?

Also, any general information on inverted flight and its effects on fuel/oil/hydraulics is welcome.


texts: What is this thing on a FDX MD11 (MD10?)?

texts: I assume something forward looking; not sure why there and how they got this to play nicely with radar


texts: What kind of wing-surface area would Curiosity need to be able to fly in the atmosphere of Mars?

texts: The rover - without wings - has around 1000 kg of mass and Mars has 38% of Earths g. The density of the atmosphere is 1% of that of Earth. Assuming the surface area of the wings could be used for photoelectric cells having an efficiency of 40% at 500W/m^2, what wing dimensions, power and speed would this airborne rover need?


texts: Do real aircraft have something close to the GPS/NAV modes in FSX?

texts:
I am a long-time flight simulator player and also very interested in aviation. In FSX, all aircraft have a GPS/NAV knob which allows the pilot to switch between direct GPS autopilot and VOR navigation Autopilot. However, when I look at the main panel of a real Boeing cockpit, I don't see a GPS knob but I do see NAV V and NAV L buttons.

I know what NAV V and NAV L are (V for vertical autopilot, and L is the same as the NAV mode in FSX that keeps the plane on course), but do real aircraft (specially Boeing) have any function to keep the aircraft automatically on course and direct it toward the destination without using a VOR? Something that works very much like the GPS mode in FSX?

And in FSX I have to manually set the VOR frequency based on the navigation chart, in real life do the pilots have to do the same, or do they have some more advanced features?


texts: What are en-route VHF marker beacons (75 MHz)?

texts:
ICAO Annex 10, Volume 1 contains a section that gives the specification for en-route VHF marker beacons. What are they?

I suspect they are a relic of the past. Are they still in use anywhere in the world?


texts:
What's the difference between an airplane that stalls nose down or just mushes in a stall?

I understand most GA planes go nose down after a stall, but some GA planes
don't drop their nose at all, they mush (they just drop in altitude).  How are these planes different?  Is their CM curve near horizontal, instead of negative, so that they fly almost neutral with little static margin? Or do they have a high horizontal tail volume and so with stick back, they just stay almost horizontal, or other?


texts: How long does it take for a contrail to hit the ground?

texts:
I'm not even sure if they end up falling to earth, or if they accumulate and form/join other clouds or whatnot, which is part of the reason I'm asking this question.

In contrails, heavier particles fall faster than the light ones, so as the contrail disperses it spreads vertically as well as horizontally.

How long does it take for a contrail to fall back to earth if at all?  If they do make it to the ground, is it then water vapor that touches down?


texts: What is the difference between LNAV/VNAV and LPV minimums on an RNAV approach?

texts: This approach shows two sets of minimums that both have vertical guidance with a Decision Altitude (DA).  What is the difference between LNAV/VNAV and LPV, and why does LPV have lower minimums?


texts: What are the printouts/paperwork a captain does at the check-in desk?

texts:
While flying American out of Chicago yesterday I noticed that when the captain arrived he went to the check-in desk and first read the monitor of a computer there for a minute or two, then he printed out a one or two page document from a dot matrix printer at the desk. Then for several minutes he made notations on the printout with a pen. Finally, he printed out a much longer document, maybe five or six pages long, folded it up, then went down the jet bridge together with the FO who arrived just as he was finishing up with the printouts.

Can an ATP, ideally an ATP who flies with American, tell me what exactly those two different printouts were and what notations he would have been making on the first one?


texts:
The common battery voltage on aircraft is commonly referred to as "28 volts".   What does that really mean in terms of a lead-acid battery?

In many uses, such as cars ("12V"), trucks ("24V") forklifts and golf carts ("36V" or "48V"), locomotives ("64V"), the nameplate number is exactly twice the number of lead-acid "cells".   But in reality, the fully charged/charging/float voltage of the system with alternator running is higher - cars 14V, trucks 28V, locos 75V.

Battery units are generally sized at 3, 6 or sometimes 4 units (6, 12 or 8 volts nominal).

So, when aircraft power is specced at 28 volts -- do they actually  mean a 14-cell lead-acid battery or  two 7-cells (which is almost unheard of)... or do they actually mean a 12-cell battery with a "float" voltage around 28V, (built out of two common-as-dirt "12V to everyone else") batteries?

I hope this isn't overloading this question too much, but when nickel-cadmium packs are used, does that have 20 cells, or 19 or some other number?


texts: Where can I find details of the holding models for JFK, Schiphol, Heathrow and Dubai?

texts: Does anyone know the stack (holding) models for the JFK, Schiphol, Heathrow and Dubai airports? I mean, not where the aircraft hold but rather how is it planned and what concepts are used? Or how I can find that data?


texts: Is there a legend for figure 15 in the Airman Knowledge Test Supplement for Instructors?

texts:
Here's why I'm asking. While using King's free practice test tool, I ran into a question:

about figure 15: in the Instructor test supplement asking about the percentage values for the MID area. I would just memorize the answer, but that's not a thing anymore, so I'm trying to find out where I can get the actual information. It seems like convective outlooks and "TSTM" outlooks are different things, as I have found both on NOAA's website. AC 00-45H only talks about convective outlooks, and doesn't even tell you the percentage values. I found this on the website that breaks it down.

But, that's not for the chart in the test supplement. The closest thing I found on NOAA's website now just shows the percentage values directly on the chart, and they are very different from the answer choices on this particular question.

I hope there is a legend somewhere staring me in the face and I've just missed it!

P.S. King says the answer is A.


texts: Can I use dual time for the 10 night takeoffs and landings required in 61.129?

texts:
For the 5 night VFR hours and 10 T/O at class B/C/D required in 14 CFR 61.129(a)(4)(ii), can you mix/match solo and dual instruction (as PIC) time for these hours and landings? In other words, are they combinable? I may reach all 5 solo but definitely have more than 5 night dual (as PIC).
Also, does being under the hood dual with CFI count? I would expect not since you're not flying "the traffic pattern" (i.e. right base, straight in, etc.) but just wanted to get consensus.


texts: Are the A400M propellers rotating in the wrong way in "Mission Impossible: Rogue Nation"?

texts:
At the beginning of the movie Mission Impossible: Rogue Nation we can see an A400M taking off.

When the engines start, the propellers turn in opposite directions. As I understand it this is not a common configuration but correct for the A400M according to Wikipedia. However, the Wikipedia article also says that the configuration is "down between engines (DBE)" which is opposite from what we see in the movie.

Did the movie get it wrong or did they use a special/early version of the A400M which worked differently?
I'm also a little confused about the propeller blades, do they have variable pitch?


texts: What should I expect for an unannounced GA visit for touch-n-gos at San Jose?

texts:
I understand that KSJC is a busy airport. I have done touch'n'gos at Oakland (also a busy Class C airport), but they have three dedicated runways for GA aircraft.

There is nothing about which runway is preferred for GA operations at SJC in the Airport Facility Directory notes.

What should I expect if planning an unannounced trip to SJC (arriving from the north/north-east)? Are touch-n-goes tolerated (i.e. staying in the pattern)? Which runway should I expect to be directed to? Is there anything else I should know?

I'm looking for local knowledge from someone with experience flying in the area, for example "GA operations are usually conducted on 30L, as the air carrier terminal is on the the other runway, and transient parking is adjacent to this runway" [I'm not sure this is the case, this is just an example of the type of information I'm looking for].


texts: How does one determine if an airplane meets airworthiness directives?

texts: There seems to be no way to determine if airworthiness directives for your airplane have been complied with. Does anyone know? I found this FAA website but you can type in a type of aircraft and nothing comes up. Also does anyone know where I can find safety bulletins for an aircraft?


texts: From which stages is the bleed air from a GE90?

texts:
I'm doing a university project on the GE90-115b engine and I'm having a hard time understanding this EASA type-certificate data sheet. In particular I can't figure out the air bleed extraction section (page 10 section 10). Is the stage number counted from the fan stage or from the LPC 1st stage?

Are there some specific reason for the choice of extraction air from "middle stages" instead of extracting it partially from low pressure stages and partially from high pressure ones?


texts: What is the safe speed to use highspeed turnoff?

texts: I understand that high speed turnoff is for the plane to exit the runway asap. What is its design specification and how fast can a plane use highspeed turnoff? Assuming only A320,737 and larger.


texts: Why can't Centre of pressure and Centre of Gravity coincide?

texts:
I understand that normally CG is placed ahead of COP so that a tail down force can make the aircraft stable. But why can't the COP and CG be placed in the same position so that there needn't be a tail down force to stabilize the aircraft.

I read an answer in Quora saying that "When the CG and CP coincides, the pitching moment will be 0 as the distance between them is 0" What does that mean?


texts: How should Isopropyl Alcohol be used as an AvGas Fuel System Icing Inhibitor?

texts:
I understand that 100% Isopropyl Alcohol (IPA) is used as a Fuel System Icing Inhibitor (FSII) additive in aviation gasoline systems—including 87 through 100LL fuel types—for cold weather operations. I know that IPA is, or can be, included as part of AvGas formulation. However, I am referring to operational use of IPA as an additive when fueling the aircraft. Pure IPA is also known as anhydrous isopropanol.

What documentation is available to support such use?
What is a proper treatment ratio for using IPA as an FSII (or what is the concentration limit)?


texts:
In my understanding, "F" stands for "fighter" (air-to-air) and "A" for "attack" (air-to-ground). E.g.,

the F/A-18 Hornet can attack air and ground targets, which is why it's called F/A-18.
the A-10 Warthog is used as an attack aircraft, which is why it's called A-10. However, it's also capable of attacking air targets using IR missiles.

The F-15E Strike Eagle is also capable of attacking air and ground targets. So why is the Strike Eagle still called F-15E and not F/A-15?


texts:
The answer to this question identifies the "pods" as tip tanks.

Why do manufacturers sometimes use tip tanks rather than wing tanks? Or is it only when the wing isn't large enough to hold the desired fuel quantity? It seems like filling the wing with fuel first would be more efficient due to less drag.


texts: On the 737NG, after deployment of spoilers automatically after landing, do the spoilers automatically go back down?

texts: So, I was just wondering whether the spoilers on a 737-800, after automatic deployment when landing, will go back down automatically, or need manual input by pilots for the spoilers to go down.


texts: What are the limitations to adding wings with engines to a helicopter?

texts:
I've probably seen this in science fiction and cartoons but never in real life. Rotor wing aircraft (helicopters) have numerous advantages over their fixed wing counterparts, and vice versa. For example, helicopters can take off and land vertically and do this almost anywhere. But fixed wing aircraft can fly further, faster and are more fuel efficient than helicopters of similar weight.

What are the limitations to adding folding wings to a helicopter, each equipped with a turboprop or turbofan whose shafts connects with the helicopter fan blade for vertical take off?

Once enough speed is gained from the vertical takeoff helicopter phase, the gearbox connects the turboprop or turbofan, they power it enough for it to generate lift at the fixed wings and when the wings are generating lift, the gear box disconnects the helicopter blades and they fold and are housed in the fuselage (like landing gear) to reduce drag. The fixed wing part of the flight takes over for faster speed, more efficient cruise and better range. The same process applies for landing.

I know there are turbofan aircraft that are a cross, their advantages of fixed wing over rotorwing are limited and their wings do not fold.


texts: Do modern Terrain awareness and warning system (TAWS) have blind spots?

texts: Do Terrain awareness and warning system (TAWS) have blind spots when the helicopter is in unknown territory with unpredicted terrain or the TAWS systems coming nowadays have each and every terrain on earth?


texts: Why do military jets sometimes have elevators in a depressed position when parked?

texts: Why do they have elevators in such a position as if the joystick is pushed forward, even though there's nobody inside the cockpit?


texts: Where can I find a database of SIDs, STARs and approaches?

texts:
I am investigating SIDs, STARs and approach procedures. I have a couple of questions about it:

Is there a way to get SID, STAR, and approach data from airports around the world? I don't mean from the AIPs but rather from a database.
Is there a way to simply calculate (some algorithm maybe?) and reproduce the shape of the legs of such trajectories? I mean some sort of simplification in order just to have an idea of what SID, STAR and approaches look like.


texts: What is the purpose of the extra wheel on the XB-70 main gear?

texts:
This photo of the XB-70 Valkyrie's main gear shows a small wheel between the two main wheels:

Courtsey of AirPigz.com

This smaller wheel doesn't touch the ground, though I can see where it might as the side walls of the main tires compress under landing weight.

The AirPigz site promised an explanation, but none has been forthcoming (in the 4+ years since that was posted), and I couldn't find any information on it on Wikipedia, either. Does anyone have any information (real or speculative) on what it's for?


texts: What is the difference between RTK GPS and GBAS?

texts: My understanding is that real-time kinematic (RTK) is also a differential GPS technology to enhance accuracy by using a ground-based station to provide the correction data to the onboard GPS receiver. Is it similar to GBAS? Then what is the difference between RTK and GBAS?


texts: How do helicopters avoid detection from enemies by using IR suppressors?

texts:
no IR suppressor

 IR suppressor

All I know is that it blends the hot air before releasing it How does an IR suppressor help an aircraft avoid detection from a missile? Wouldn’t the entire helicopter show up on the IR?


texts: Can thrust be produced only using the forward speed of a nozzle?

texts:
Why can't a nozzle that is already in relative motion to the air produce thrust by speeding up the air that passes through inside it?
So let's pretend you're in a glider with two converging nozzles (without fans or burning fuel), one attached to each wing. Shouldn't the air passing through speed up due to continuity, and provide a forward force on the plane?
Obviously this does not work in real life so I would like to know why. Is it because the bottom an top surfaces essentially function as a diffuser, which slow the air around?


texts: How is the actual ground speed of an airliner measured?

texts:
Do pilots have the "ground speed" information available?

If so, how is the ground speed measured? Or do they rely on GPS info to calculate it?


texts: how to simulate the performance parameters wand EGT parameter?where can i get the data?

texts:
I went through a lot of research papers and (kind of) understood the parameters needed for Engine Condition Trend Monitoring. From what I've understood, I need N1speed,N2 speed, Pitch, AOA, Exhaust Gas Temperature, Fuel Flow, Low Pressure Fan Speed, High Pressure Rotor Speed, Engine Pressure Ratio and EGT Margin data.
I'm doing this as a part of my Mtech project and I need some sample data to start working. Also, please correct me if I'm wrong because I'm very new to all this.


texts: Where is RC aircraft flying allowed in the US?

texts:
In the US, where are you allowed to fly RC aircraft? AMA says you should stay away from airports and below 400 feet. Is there any actual law about this?

I'm guessing you are free to fly on your own property. How about other places? Does it have to be an actual RC field? Can it be a park, as long as you don't endanger anyone?

If this varies with local rules, is there some reference for finding more information about which areas allow/disallow it?


texts: When do the lift and drag vectors contribute a force component along a glider's path of travel as seen from the ground?

texts:
It is often said that the lift vector helps to propel a glider forwards.  The lift vector has no component acting parallel to the glider's trajectory through the airmass, but in many cases the lift vector does have a component acting parallel to the glider's trajectory as seen from the ground.  Note that for a given airspeed, the direction of the glider's trajectory through the airmass-- i.e. the direction that is exactly opposite to the "relative wind" that is "felt" by the glider-- is not affected by sustained updrafts, downdrafts, headwind, or tailwinds.  But this is not true of the glider's trajectory as seen from the ground.  A glider in a powerful mountain wave updraft may be rising straight up as seen from the ground, while the trajectory through the airmass will still be the normal glide path that would be obtained at whatever airspeed the glider is flying at.

Under what circumstances does the lift vector of a glider contribute a force component along the glider's path of travel (trajectory) as seen from the ground?

Under what circumstances does the drag vector of a glider contribute a force component along the glider's path of travel (trajectory) as seen from the ground?

Likewise for a powered airplane.

Note -- to avoid any possible ambiguity, please be aware that this question is using the word "lift" exclusively to mean an aerodynamic force generated by the aircraft, not to mean rising air.  These are two completely different things.

Note -- the scope of this question is meant to be confined to linear (but not necessarily horizontal) straight-line flight with constant airspeed and groundspeed, at least over the short term.  We're assuming the glider (or airplane) is flying in an airmass that is locally uniform. In other words, if the glider has entered a thermal updraft or penetrated through an abrupt wind shear or flown from sinking air into a ridge updraft or wave updraft, we're assuming that it has been in the new airmass long enough to come into equilibrium, so that net force is zero for the time being.  This is not a question about "dynamic soaring" as practiced by the albatross over the open ocean, r.c. glider pilots flying in loops on the lee side of the hill, someone trying to put into practice Taras Kiceniuk's ideas about exploiting the boundaries between still air and downdrafts as a source of energy, etc.  Those subjects are worthy of an ASE question, or many questions, but this is not that question.


texts: How much thrust can the thrust reversers create?

texts:
Let's say for the sake of the question, the plane is an 787 Dreamliner and the engine is the General Electric GEnx-1B64 (that according to Wikipedia can produce a maximum thrust of 284 kN)

In comparison to the "regular forward" thrust that a jet engine can generate, how much thrust can we apply to this engine in the reverse mode?
Can we apply full power in the reverse mode?


texts: Inviscid aerodynamics: why is circulation zero at the wingtip?

texts:
I read that the circulation at the wingtip for a finite wing is $0$. I am a little bit confused about this statement. First, it is said that drag due to lift (aka induced drag) generates vortices at the wingtip. But on the other hand in Prandtl's lifting line theory the circulation at the wingtip dies off. I thought about some explanations but I would like to know which one is really true. I also welcome any additional explanations.

Pressure difference at wingtip is $0 \implies $ no lift $\implies \Gamma = 0$.
Indirect: If the circulation at the wingtip is not equal to $0$, then the downwash due to wingtip vortex is infinitely large, which is not possible. This gives $\Gamma =0$ by contradiction.


texts: Can the touchdown RVR be replaced by the midpoint or rollout RVR?

texts: When there are three RVRs equipments in place and an ILS approach chart minumum for the runway simply says "RVR 800m" without any additional notes, is the touchdown RVR the only controlling RVR? If so, what if the touchdown RVR is out of order? Can the touchdown RVR be replaced by either the midpoint or rollout RVR?


texts: What is the standard rate of turn for heavy aircraft?

texts:
I have heard and read many times that for "heavy aircraft", they use a standard rate of turn which is 1.5° per second (4 minute turn), but I have never found an official source which addresses this. Although... I'm actually not even sure where the normal 3° per second (2 minute) standard rate turn is defined either.

The wikipedia entry on ROT (Aviation) says:

  Light aircraft are equipped with 2-minute turn indicators while heavy aircraft are equipped with 4-minute turn indicators.

I don't see why "heavy" would have anything to with turning rate, but airspeed certainly does.
So, I'm wondering if this is true, or just something they think is true because airplanes often use half-rate turns at airspeeds above 250 knots and bank limiting prevents them from making a standard rate turn at airspeeds above ≈ 200 knots?


texts: Where can I find the specific power output of a specific NDB?

texts:
As a rule of thumb I can get an approximate range of an NDB with the formulae:
Over sea: range=3SQRT Power
Over land: range=2SQRT Power
To use this formula I need to find out what Power has the NDB that I need to use; Where should I look to find out?


texts: How often do runways need to have typical maintenance?

texts:
At a large airport (think Heathrow, JFK, O'Hare), I would imagine that the runways take a lot of abuse from all the huge planes landing on them.  So, a quick multipart question:

How do large passenger planes damage runways?  Does it differ depending on the surface?
How long can a runway sustain this damage before the runway must be repaired or resurfaced?

Keep in mind, I'm talking about normal wear and tear.  So, I'm not really wondering how long it takes to repair a runway after a 767 lands with it's gear up, for example.  Rather just wondering how the normal maintenance cycle works.


texts: Is a failed ditching of an aircraft also Controlled Flight Into Terrain (CFIT)?

texts: Does CFIT apply in case of a plane (not an seaplane) failing a "landing" emergency in the open sea?


texts: Does a military equivalent to civil ATC exist?

texts:
There are specific military ATC facilities, e.g. at military airfields, or temporary airstrips:

Mobile ATC towers used by US Air National Guard’s for access to hurricane-devastated areas. Source: AAR

But is there usually an overall specific military ATC system for training and/or war operations so that:

Military aircraft / formations are kept separated.
Drones and aircraft don't collide.
Military traffic is well-ordered over large areas.

The scope for answers could be NATO or other large military organization worldwide.


texts: Have there ever been any accidents within holding stacks?

texts:
At a busy airport, up to a dozen aircraft waiting to land may fly the same holding pattern at the same time, separated vertically by 1,000ft. — a stack. Some ATC towers have dedicated Stack Controllers.

It's all very routine, but have there ever been any instances of incidents or accidents in stacks?

To the layman, it might seem like stacks could be hazardous — e.g. what if a plane in the middle of a stack lost an engine?


texts: What are the rules for Public-Use Operations?

texts:
On another aviation board I'm on, (link), one poster is making the claim that operators of airplanes for Public Use Operations (eg. Police planes, Search-and-rescue aircraft, most government planes), do not even technically need a pilot's license, and do not have to meet FAA maintenance rules.
He even cites an FAA Advisory.

I find this extremely hard to believe. But I haven't found anything to refute this.

What are the rules for Public Use Operations, and what role does the FAA play in keeping them safe?


texts: Why is the nosewheel of the MiG-29 placed in front of the engine intakes?

texts:
Why do MiG-29 have a front-wheel of landing gear placed in front of an intake? would not it throw water or stones into the intake as mentioned in Raymer?

I am designing an aircraft based on the reference aircraft MiG-29.
I have used an RD33 twin-engines with twin intakes placed in chin position beneath the fuselage. Which design configurations should be kept in mind?
The intake I have selected is a ramp intake.


texts: Was Stringfellow's 1848-1868 motor a revolutionary aviation engine or just a useless low efficiency toy which never powered a flying model plane?

texts:
I took a look at the 1848 Stringfellow's aviation steam engine and I do not really understand how it was capable to power a model plane in horizontal flight as long as the motor itself was just an ordinary toy of the time and the boiler is a below-average design, as long as the fire is not surrounded by water from all sides to transfer the energy of the fuel with maximum efficiency to the working fluid. The fire burns around the upside-down cones containing water and it radiates a good part of its energy through the thin metal walls of the boiler.
The Scientific American (Vol. 20, Iss. 11, p.69; Mar 13, 1869) says that a later version of this engine (1868) achieved a pressure of 100 $lb/in^2$, after 7 minutes from the moment the fire was started, and was able to turn two propellers 3 ft in diameter at 300 rev/min. The dry mass of the motor and boiler together was 13 lb.

IS A FLYING MACHINE A MECHANICAL POSSIBILITY?
… The organization of the Aeronautical Society, which gave its first
exhibition at London last June, is an evidence that the belief is
gaining rather than losing ground. … what are we to say of an engine
weighing only sixteen lbs., and being able to work to one-horse power?
The council of the society voted their £100 prize to Mr. Stringfellow
for an engine of this description; and whether or not it ever becomes
the motive power for flight, it would seem, from its ingenuity, to be
well worth the reward. “The cylinder,” the report tells us, “is 2
inches in diameter, stroke 3 inches, and works with a boiler pressure
of 100 lbs. to the square inch; the engine working 300 revolutions per
minute. The time of getting up the steam was noted; in three minutes
after lighting the fire the pressure was 30 lbs.; in five minutes, 50
lbs.; and in seven minutes there was the full working pressure of 100
lbs. When started, the engine had a fair amount of duty to perform in
driving two four-bladed screw propellers, 3 feet in diameter, at 300
revolutions a minute.”
The data for calculating the power are taken as follows: Area of
piston, 3 inches; pressure in cylinder, 80 lbs. per square inch;
length of stroke, 3 inches; velocity of piston, 150 feet per minute; 3
× 80 × 150 = 36,000 foot-pounds. This makes rather more than one-horse
power (which is reckoned at 33,000 foot-pounds). The weight of the
engine and boiler was only 13 lbs., and it is probably the lightest
steam engine that has ever been constructed. The engine, boiler, car,
and propeller together were afterwards weighed, but without water and
fuel, and were found to be 16 lbs.”
This engine seems to demonstrate the possibility of making engines
light and powerful enough for purposes of flight.

However, nothing is said about the capacity of the boiler to maintain a suitable pressure for, say, at least 30 seconds, an interval of time that would have allowed a short flight. Another thing would be, if this engine was able to fly a model plane in 1848, why did it not repeat the performance in 1868?

Source: John Stringfellow, engine, 1848
With the data in the Sci. Am. article of Mar 13, 1869, I calculated that Stringfellow's engine needed 1.54 liters of steam at 5.44 atm each second in order to work at the desired power.
Judging from the total size of the recipients that contained the steam (which is below 15 liters) and the time needed to reach the necessary pressure, of the order of 7 minutes, this engine would have functioned at most 10 seconds and then it would have needed a few minutes to build up again enough pressure for another few seconds of generating mechanical power.

Source: The Conquest Of The Air
Question: Was John Stringfellow's 1848-1868 motor a revolutionary aviation engine or just a low efficiency toy well behind its time? Was this device really capable to power the 1848 model aeroplane of the above mentioned inventor?
(A link to an exact working replica of the 1848 engine and plane would answer my question immediately.)


texts: Is it feasible to add an aftermarket hydrofoil to a light aircraft?

texts:
Could long, aftermarket hydrofoils be added to the water-skids of a plane (like this Cessna with pontoons or smaller)

Cessna 208 Caravan
not designed to have a hydro foil, to increase its ability to land on choppier water?
In theory, the pilot would first enter the water with the skids, clear of the chop, then stall the hydro foil similar to stall landing a plane thus giving the plane a soft or possibly vertical landing.

Grumman JRF-5 with hydrofoils


texts: What prevents Low Cost Carriers (LCCs) from cutting cost that compromise safety?

texts:
I was reading an article about LCCs and here is an excerpt that got me thinking.

  While budget airlines cut other corners to keep fares low, they do not
  — actually cannot — compromise the safety of their passengers in the
  process.

What prevents low-cost carriers from cutting corners that might compromise the safety of their passengers?


texts: When may passengers board the aircraft and who makes the decision?

texts: Who decides when the passengers may board the aircraft? Is this a pilot or cabin crew decision, and what are the prerequisites / conditions (cabin checks completed, flight plan filed, ...?) for this decision?


texts: What are the differences between turbojet and turbofan (low and high by-pass ratio) in the graph of thrust relative to speed?

texts:
What are the curves of thrust relative to velocity of the turbojet, low-bypass turbofan and high-bypass turbofan engines from static thrust to Mach 4 generally. Approximation is okay as long it has any Mach or other speed values. Graph is preferred, because most graphs of these values I have found are starting at around Mach 0.5 or completely without any axes description.
Mostly I want to know is what difference there is at speeds of 0 to Mach 1 in these three engine types.
(I have wrote question containing around 400 words so I reduced it to this after getting suggestion its too long)


texts: What do the components of a shockwave's visual artefacts represent?

texts:
On a recent flight, I was able to observe visual artefacts over the wing (Boeing 767-300 in cruise).

You can see them in the image below; they look like creases in a surface. They moved forwards and backwards over the wing. Later in the flight they extended to the end of the wing; at this point, they extended no further than a few metres.

I've added red and yellow arrows pointing to their ends - as you can see, one of them appears to fork.

Adjusting brightness and contrast makes the artefacts more visible:

I understand that this artefact is caused by a shockwave produced by supersonic airflow over the forward part of the wing.

I'd be interested to know: what exactly is it that I am seeing?

Is the artefact projected onto the surface of the wing, like a
shadow?
Is the artefact a refractive distortion caused by different air
densities?
In this image, there appear to be two creases, one behind the other -
what do they represent?
What does the fork at the right-hand end of one of the 'creases'
represent?
What do the darker and lighter portions of the 'creases' represent?


texts: Explained intuitively, why does aspect ratio affect induced drag?

texts:
Over the last few hours, I've been trying to intuitively understand induced drag, and how aspect ratio affects it. I already know the equations, but while they explain the relationship, they do not really explain anything, I want to understand what is happening physically. I've read on many answers in this community, specially by Peter Kämpf, but I've been unable to attain an intuitive understanding.
I will explain my line of thinking, hopefully I can be corrected on any misconceptions, or wrong assumptions.
First of all, my way of thinking about lift is simply airflow being redirected. If airflow is redirected by a surface, a force in the opposite direction is applied on said surface. This means that for lift to be generated, downwash must exist, therefore induced drag is an inseparable side-effect of generating lift.

Let's imagine 2 theoretical wings, both of which have the same area, but differ in aspect ratio.
If induced drag depends on the downwash angle, why would a longer wingspan reduce the angle? If the downwash angle is reduced, then the amount of air being redirected (total mass) must increase to keep lift equal, how can that happen when the wing area is equal?
All of the sources I am able to find blame induced drag solely on wingtip vortexes, since they cause downwash, but the entire wing is creating downwash, so what gives?
If tip vortexes are what cause induced drag, how does a longer wingspan reduce the induced drag coefficient? As an example: If the span of rectangular a wing is increased without changing the chord length, the aspect ratio will increase, which according to the math, will lower the induced drag coefficient. How does a longer wingspan affect the vortexes such as to reduce the downwash?


texts: Why does the FAA not support UL102 (formerly 100SF) unleaded av-gas as an alternative to 100LL fuel?

texts: The specifications for UL 102 are described in this Wikipedia article.  The fuel appears to exceed the specifications of 100LL in octane number and energy per unit volume although the fuel weighs 7 pounds per gallon instead of the 6 pounds per gallon for 100LL.  Is the additional weight the reason the FAA rejected this fuel as an 100LL alternative?


texts:
Is military grade jet fuel more expensive than civilian grade?
Why are governments moving away from military grade jet fuels?


texts: Why do different sites list different lengths of the lower deck bulk cargo compartment for the A330-300?

texts:
From the following two links for Airbus A330-300, the length of "lower deck bulk cargo compartment" has two different values.

a) Air China lists the value as 511 cm

b) Airbus (see pg. 112) lists the value as 404 cm

Why?


texts: What would the altimeter indication be through a cold front?

texts:
Cold air is heavier than hot air because of its greater density, so the QNH of an airport inside a cold front would be higher. Flying towards the cold front would be, "low to high, hello sky".

But I also know that for altimetry, cold air generates lower pressure inside the pitot-static system than warm air, and it would increase the altimeter reading, so "hot to cold, look out below".

I'm confused because of the 2 contradictory factors. If we fly towards a cold front without adjusting the altimeter setting, would there be an increase or a decrease in the indicated altitude?

There's an ATP question:

  Event after an aircraft passes through a front into the colder air.

Answer:

  Atmospheric pressure increases.

Well, yes, that's why QNH would be higher, but our altimeter would sense the temperature and "feel" a decrease in atmospheric pressure.

So, what would be the real indication of the altimeter in this situation?


texts: What Transponder code to use flying between Oakland and Hawaii?

texts: Where to find the appropriate Transponder code for crossing the Pacific?


texts: Does Daylight Saving Time affect the flight time?

texts:
Say an example flight FRA-LHR, was scheduled say 9am every day. Now will that flight be then moved to 10am once the change to DST happens or will it remain at 9am?

I would expect the flight times schedule to remain the same i.e. the daily morning FRA to LHR flight will be always departing at 9am (independent of summer/winter time changes). My knowledge in this area is limited so I wanted to know what the experts on this site say.

My question is more directed at the flight schedules i.e. the daily flight scheduled at 9am for example - does it undergo schedule change and is moved to 8am/10am or is this time fixed (underlying assumption being: in general a flight is scheduled for a certain time to meet a demand, so moving the local time is not necessarily feasible).


texts: is it mandatory you put a ground cable for airbus aircraft parked over night?


texts: Will occupants usually survive a decent autorotation?

texts:
When I learned to fly helicopters, I of course spent significant time learning about and practicing autorotations.

The CFI at my school, who had around 15,000 hrs (that's right, fifteen thousand!) said a few times that practice, knowledge and currency are vital — but as long as you got the entry right (following which you can fly to the ground) and executed at least a decent attempt at the flare and cushion, you would survive. Is this a correct take on the survivability of an autorotation? Do fatalities arise primarily from errors during the autorotation entry or flare?

While you might not get to use the machine again, and you might spend some time in hospital, you would live to fly another day.  I am assuming a reasonable place on dry land is available to finally come to rest and no post-crash fire.


texts: Is there a 180HP conversion available for a 2011 160HP Cessna 172R with a Garmin G1000?

texts: I've recently purchased a 2011 172R (160HP) with a G1000 on the sellers promise that I can apply a propeller switch and modified air intake STC to get the derated engine back to 180HP. However, the holder of said STC, AirPlains, shows the kit is only applicable to 1996-2004 172Rs without a G1000. Are there any other manufacturers that can apply this conversion on a later-model 172R, or am I stuck with my 160HP?


texts: Do Military Turboshaft engines have a distinctly different sound from Civilian ones?

texts: I live in India, and near an airbase so there are a moderate amount of helicopters flying overhead. My friend claims that he can distinguish between a civilian helicopter or a military one based on the engine noise. He says that military helicopters have a higher pitched whine in their noise that is absent from civilian ones. I have heard it myself but I have no idea if it's perception after he told me or reality. Is there any truth to this? Keeping in mind that most military choppers are Russian/Soviet designs in India while a lot of civilian choppers are Bells


texts:
An answer to another question on Aviation.SE asks about the historical development of FAR 61.57.

How has FAR 61.57 changed over the years?


texts: Why is there a difference in the max spoilers extension between the A320 and A321 in a roll?

texts:
I was recently reading the Flight Controls chapter in the FCOM and I read that spoilers 2-5 extend a maximum of 35 degrees on the A320 however on the A321 spoilers 2,4 & 5 extend a max of 35 degrees but spoiler 3 extends only a max of 7 degrees (during a roll).
What is the reason behind this?


texts: Cruise Mach Number less or more than Critical Mach Number

texts: Do commercial airplanes cruise at Mach number higher than the critical Mach number? And what is the critical Mach number of airplanes like B777 or A330?


texts: Are taller landing gear bad for aircraft, particulary large airliners?

texts:
Buiding larger engines for larger aircraft as opposed to smaller but many engines has proved to result in more fuel efficiency.
Having established one of the main drawbacks or impediments to building larger engines are ground clearance for engines in light of aircraft/airliners in their current under wing configuration. This configuration in light of current technological advancements seems to offer the greatest advantage in terms of control of the aircraft, stability and weight closest to the center of gravity when flying among other things.

If space to store the retracted gear were not a problem due to some new design, are taller gear for airliners necessarily undesirable for landing and take off? Do they present some technical problem if for example they were strengthened, the extra length would present some problematic leverage problems as they get closer to the pivot and "load"?


texts: What happens when an airplane stalls and why do pilots practice it?

texts:
When a non-pilot hears the word stall, it brings to mind what happens when a car stalls -  the engine quits. It seems like that would be a dangerous scenario in an airplane.

From a non-pilot perspective, what happens when an airplane stalls and why is it important for pilots to practice it?


texts: In the gyroscopic precession left turning tendency, why does a pitch down cause a forward force at the top of the propeller?

texts: I'm a student pilot, and all the textbooks and online resources I'm reading show a pitch down as a forward force acting on the top of the propeller (causing the resulting forward force on the right side of the prop, thus a left yaw). Where does this force come from? Isn't a pitch down a downward force on the prop hub, since the rotation is occurring about the airplane's center of gravity (behind the prop)?


texts: Do flight schools typically have dress codes or expectations?

texts:
I attend a local flight school for lessons once or twice a month. I normally wear a hoody and some tracksuit bottoms as they are comfortable for me and I like to be comfortable whilst doing something that I need to apply focus to (I dress similarly for my job as a developer).

Most people that are there for lessons are dressed very smartly, usually in a shirt and tie. I presume this is because they want to impress people, as they are attending the airport they hope to work at in the future (it's a big airport). I am just doing this for a hobby, but the fellow students often look me up and down, usually looking confused and/or disapproving.

Do flight schools typically or traditionally have more formal dress codes or expectations than this? Are there substantive reasons for why certain clothing choices would be required or expected?


texts: What would prevent the installation of windows on the roof of an airliner?

texts:
What prevents airline manufacturers from putting a strip of glass along the roof of the aircraft? It would be a good addition in terms of cabin view, light inside the cabin, etc.

Would it compromise the structural integrity too much?

Edit: The image is for representational purposes only. My question does not pertain to a installation similar to this image


texts: How does the CFM LEAP-1B engine achieve the same efficiency as the LEAP-1A despite its lower bypass ratio?

texts:
The CFM LEAP engine comes in 3 variants (1A, 1B, 1C). The larger LEAP-1A and LEAP-1C variants have bypass ratios of 11:1, while the smaller LEAP-1B only has a bypass ratio of 9:1.  For turbofan engines, we know that the higher the bypass ratio, the higher the propulsive efficiency of the engine, which results in a lower fuel consumption.

So how does the CFM LEAP-1B engine achieve similar efficiencies to its larger siblings when its bypass ratio is considerably lower?


texts: Has anyone created (or proposed) a database or clearinghouse of local and state codes, restrictions and prohibitions applicable to UAS?


texts: What implications does automobile electrification have for the supply and cost of Avgas?

texts:
The electrification of automobiles has been picking up pace recently, with various countries and manufacturers setting targets for an electric- or electric/hybrid- only future.

If these plans come to fruition and are widely adopted, the demand for gasoline, and therefore its supply, would decrease considerably. While avgas is something of a specialty product, I would guess that it shares the bulk of its components, and their manufacture, with automobile gasoline.

Have there been any studies of the consequences of this change on the inflation-adjusted cost and its supply of avgas (though I imagine it will be available at some price), and also on motor gas for those aircraft that can use it?


texts: Can the ILS glideslope be intercepted from above?

texts: Is it recommended to intercept the ILS glideslope from above? Are there any special considerations like unstable approaches or GPWS warnings?


texts: Why has aluminium, rather than steel, prevailed in airliner construction?

texts:
As any cyclist knows, steel has many advantages over aluminium:

it's stronger (for the same size)
it can handle greater forces without needing to be stiffer
it has better fatigue characteristics
it's easier to work with
and most importantly of all, it offers a more responsive and comfortable ride.

On the other hand aluminium is much lighter (for the same strength), which obviously is pretty important in an aircraft.

Even so, steel-framed bicycles aren't always heavier, or significantly heavier, than aluminium-framed bikes of similar strength, and in engineering the strength of a construction is not only determined by its materials, but also its design.

When did aluminium become the default material for the vast majority of an airliner's construction, and is its strength-for-weight advantage the principal reason?


texts: Can experts identify the model using this part (FOD prevention purposes)?

texts: We found this part of an aircraft recently and, in order to improve the safety levels at our airport, we would like to know what possible aircraft model (or models) are compatible with this cover so we can locate it.


texts: How realistic was the airplane scene in Terminator Dark Fate?

texts:
In the movie Terminator Dark Fate, the C-5 Galaxy Grace (Mackenzie Davis) is flying gets hit by another plane (I think it's a KC-10 Extender) piloted by the Rev-9 Terminator.

What I want to know is how realistic (or not realistic) is this scene. Wouldn't wake turbulence cause an issue?

Part 1 of the scene:

Part 2:


texts: What are the advantages of a Pelikan tail compared to a V-tail?

texts: The Pelikan tail was originally proposed for the X-32.  Why was the Pelikan tail proposed rather than a V-tail?  What advantages and disadvantages does the Pelikan tail have compared to a V-tail or a conventional tail?


texts: Why was Concorde never sold as a private business jet?

texts:
Airliners like Boeing 747 and even Airbus 380 are at times considered as personal jets for extremely wealthy people. Looking from the side, Concorde was ideal for this role: while not very big, it probably could provide luxury transportation for ten VIPs or thereabout, adding to that something that looks more valuable and more exceptional than just a "flying palace" - speed like no other. New supersonic aircraft like Aerion AS2 are often seen in this role. However, it looks like rich individuals only bought various bones of Concorde after retirement.

The fate of F-BVFD looks especially strange. As I understand, it has been retired very early, in airworthy condition, just for being a surplus aircraft. After standing for many years in the open air, it deteriorated and then has been scrapped. I cannot imagine it to cost a lot during these years of standing. Why did nobody try it for personal use? Also, some pre-production aircraft have been retired after logging not so many hours and were airworthy.

Surely, Concorde uses lots of fuel, but probably the A380 burns no much less if per flight (not per passenger). And it only could fly supersonic over sea, but was surely capable of the fastest possible subsonic flight over the land.


texts: Is it possible to see the same sunset twice from an aircraft?

texts:
If I initiate a climb just after watching the sun go down below the horizon, how fast would I have to climb in order to watch the sun come back up, so that I could then level off and watch the sunset for a second time?

I've Googled the answer, and several different articles have said that I'd need a minimum rate of climb of 5000 ft/min. However, I've also read several articles that said you can do the same thing in the Burj Khalifa's elevator, and it maxes out at 2000 ft/min. So, which of these is correct, if any?


texts: Is there an exact solution for induced velocity during vortex ring state?

texts:
In plots such as these, the section between -2 and 0 has no exact solution. As shown in the first image, the other two formulas are known, but not during vortex ring state because, as seen in the second image where the functions continue, neither match the data. After a bit of analysis, I have found that the following function is a close fit to the approximation given in the first image:
$$f(x) = \sqrt{1-\frac{x^2}{4}} + \frac{x(x^2 + x - 1)}{2}+\frac{4x^3}{x^3-8}$$
But I am not aware of any way I could even go about proving this is or is not the exact solution.
Thanks


texts: How do we get Required RVR or Actual RVR for an instrument approach?

texts: When executing an instrument approach, when the pilot should start reference the RVR reported. Also, How do we get the required RVR for the current approach in execution and actual RVR. I think actual RVR can be part of METAR data. But I am not sure on the required RVR.


texts: How much aluminum was used in the Boeing 727?

texts: What is the weight of aluminum used in the Boeing 727 fuselage? Do you know where I can find it? Any manual or site or something like that?


texts: How are insects and arachnids kept out of commercial passenger airliners?

texts:
If a commercial passenger airliner were to land in a place infested with insects or arachnids, wouldn't it be dangerous to have those animals enter the aircraft?

For example, suppose if mosquitoes, bees, or spiders were to enter the cockpit, wouldn't that be a huge distraction for the pilots? Wouldn't that potentially compromise the safety of the passengers?

The main questions are:

Are there established methods/protocols/regulations for ridding aircraft of potentially dangerous insects?
If so, what are they?

(Note: I am new to all of this. A thought occurred to me that mosquitoes onboard aircraft could potentially endanger the passengers onboard).


texts: Why don't short-haul regional jets go for composites?

texts: We have seen Airbus and Boeing going all the way for composites on their A350 and 787, but when it comes to smaller planes like the Embraer E-jets or the Bombardier C-series, they choose to use aluminium, I'd like to know what are the reasons for this to happen, why is more cost-effective?


texts: Why do high altitude sky-divers say 'Exit' multiple times?

texts:
This is something that has always puzzled me.
https://sndup.net/6vn8/a

Unfortunately, I can't find a video in which I heard them say it, but right before they left the plane, I heard

  Exit exit exit exit exit exit

through a radio or megaphone.
I found audio of this, but maybe you might not be able to benefit from it because there are no visual cues.


texts: How are disabled passengers evacuated during emergency?

texts: Basically the title. However, I would request if someone can throw some light on how FAA or the airlines train the crew to handle emergency evacuations with a disabled person on board. Are the ramps and slides accessible to persons with disabilities?


texts: I read a lot about boundary layer but I don't know exactly what boundary layer is yet.


texts: Why is the time of useful consciousness only seconds at high altitudes, when I can hold my breath much longer at ground level?

texts:
This answer says at FL500 (50,000 ft; 15,250 m) the time of useful consciousness is only 6 to 9 seconds.

But if I just stop breathing at any arbitrary time, without any preparation, I can easily continue without air for about 20 seconds. How can these times be so short?


texts: What effect does driving convictions have on a PPL?

texts:
Recently, I was driving some friends around when they started complaining that I was driving "too slow" (basically not over the speed limit). I stated that my reason for being cautious was I did not want to jeopardise my PPL / NPPL (in progress).

I would like to know however, what driving convictions actually do affect pilot licenses or get them revoked?


texts: If a plane had a laser/infrared ruler its four extremities pointing downward, could that work as an altimeter device?

texts: Laser noob here. I don't know what the maximum range on a high powered laser is, nor a low-powered laser for that matter. Just wondering if this is at all possible. I mention four extremities because it would a combination of the four different laser readings of height. I guess it could be most useful over water, but things could get complicated if flying over rough regions with mountains and valleys, but could be helpful if use in conjunction with a map.


texts: What is area in equation of lift?Does it remain constant during flight?

texts: I am beginner & learning aerodynamics concept. What is area in equation of lift(L) =Coffecient of lift x area x density x square of velocity/2. Does increase in angle of attack increases the area & thus increasing lift?


texts: What does the term "tanker" mean when used in regards to a passenger airliner?

texts:
In a comment on this answer:

  Airlines will tanker fuel if it's substantially cheaper at another airport

I've wondered what that term meant before, and now this comment leads me to think that airliners will carry more fuel than what's required for a trip, because carrying the fuel might be cheaper than buying it at the next airport.

Can someone provide more detail on why and when an airline might do this, the calculations that are involved, and any other interesting information on this topic?


texts: Am I Required to Use the Runway Advised by a Unicom?

texts: Let's say that an uncontrolled airport's ASOS reports wind 060 @ 6 knots.  The airport's unicom advisory states that Runway 22 is in use.  Am I required to use Runway 22, or can I use Runway 4?


texts: Were inclined runways ever under consideration?

texts:
A long time ago I read an article (in Popular Science, probably) of a plan for an airport runway constructed on a grade, so that one end was ten stories higher than the other. The idea was to save gas: at takeoff, the plane would be going downhill and get a speed boost from gravity. When landing, the plane would be going uphill, and take less engine power to stop because gravity is slowing it down.

Did anyone ever research or actually test this plan? Does it seem practical?


texts:
We have several questions here about what happens to an aircraft when it gets struck by lightning (e.g. this question), and at least one answer from a former pilot who knows he was struck once and thinks he was struck other times. How frequently do aircraft get struck by lightning?

Additional commentary on how do you know you've been struck would be appreciated, but I'll make that a separate question if it's more appropriate.