texts: What are these engine gauges in the Comet 4 for?

texts:
What are these gauges on the Comet 4's engine-gauge panel (between the captain's and first officer's instruments, above the throttle levers), marked "POWER LOSS INDICATOR", for?  (Sorry for the blurry image.)

(Image cropped and annotated by me; original by Geni at Wikimedia Commons)

I'm assuming they're engine gauges of some sort, since there're four of them and they're located immediately below the engine RPM and EGT gauges (and above the throttle levers); could they be for monitoring engine performance during hot-and-high takeoffs?

They are apparently not present in the Comet 1, which instead has engine oil temperature/pressure gauges in this area (see pages 59-60 of this PDF, marked as pages 58-59).


texts: Choosing $\phi/\beta$ in Lateral-directional control design

texts: In designing the Lateral-directional controller for aircraft, there is a parameter called $\phi/\beta$ that is defined as the ratio of the magnitude of the bank angle to the sideslip envelopes in the dutch-roll mode. For example in MIL-STD-1797, a lot of requirements are based on this parameter. However, there is no clue how this parameter is chosen itself in the design process. How can one choose this parameter in the design process?


texts: Why does the SSM decoding vary between different A429 label types

texts:
For A429 there are different label types, for example: BCD, BNR, Discrete...
These types have their corresponding SSM (Sign/Status Matrix) that is unique, for example an SSM of "00" represents a failure for BNR but represents a normal operation for a Discrete.

Could someone explain why is that the case? Why not just have a the same SSM interpretation for both Discrete and BNR?

I looked online for an answer but to no avail.

Thank you


texts: Do hot air balloon pilots file flight plans?

texts: Are hot-air balloon pilots ever required to file flight plans? (can they file?)


texts: Could a landing gear jettison mechanism be practical when ditching?

texts:
Reading this answer about GA aircraft ditching, I wondered if, considering conventional fixed landing gear aircraft (taildraggers) which often operate overwater, having the ability to jettison the landing gear before ditching would increase safety by reducing chances of flipping inverted when wheels contact water?

Regardless of how this mechanism would work, explosive bolts or manual release mechanism, would this added complexity/weight be practical considering ditching probabilities, and are there been studies about this?

Here's a video showing one Cessna with retractable landing gear, ditching gear up, avoiding it to flip inverted.

https://www.youtube.com/embed/8rr2ZjGbdAA?start=23&end=33


texts: What are the drawbacks for manufacturing a large airliner capable of water landing?

texts:
Emergencies are rare but still occur. Apart from weight and extra fuel costs, What are the drawbacks for manufacturing a large airliner capable of water landing in case of an emergency?

Assuming the extra weight problem could be mitigated through design and cost cutting techniques and advances in material science would this be feasible for airliners?


texts: Why are special aircraft used for the carriers in the United States Navy?

texts:
Why are aircraft such as the legacy F-14 and now the F/A-18 used by the US Navy carriers?

It seems to me that developing a new aircraft from the ground up is very expensive. Is it not possible to have converted F-16 or F-15's for carrier operations? Obvious modifications such as folding wings, stronger undercarriage, hook, etc. I'm sure there are many more I'm not aware of.

Is the reason that these aircraft (F-16, F-15) are not suitable for carrier operations, even with modifications?

Isn't this what the Russian Navy did with their fighters? The carrier versions of the MiG-29 and Su-27?

What are the reasons the US employs unique carrier aircraft? Is the reason political? Technical?


texts: what is the highest and lowest air pressure induced by an aircraft at supersonic speeds?

texts:
When an aircraft is supersonic, is the greatest pressure at the wing leading edge, below the wing surface or in front of the shock wave, or another location all together.

Also is the lowest pressure at the upper wing surface or behind the shock wave or another location all together?

Is there a pressure range for these values just to give a point of reference?


texts: What is the average climb gradient of an aircraft during the takeoff and early phase of a departure procedure?

texts:
On chart plates it is written the minimum climb gradient with which an aircraft should climb for obstacle clearance or after ATC request (for traffic flow management etc.).

However, since this is the minimum required climb gradient, I am curious about what practically happens during real flights. For example, if a chart plate instructs an initial climb with a minimum climb gradient of i.e. 320 feet per nautical mile, will the aircraft try to maintain this minimum climb gradient until the termination altitude? Will it climb with the maximum climb gradient that its performance characteristics allow?

In other words, given an assigned climb gradient from a chart plate (i.e. from DEEZ5: "Standard with minimum climb of 250' per NM to 300), what would the average climb gradient of an aircraft during the initial climb phase be, provided that this value is taken into consideration not only for a lower but also for the calculation of an (hypothetical) upper limit?


texts: Is it common for jets not to have backup manual control system for emergencies?

texts:
In July 1989, the United Flight 232 crashed in Sioux City, Iowa, while the pilots were trying to land on the runway without any yoke control. Today, I was reading the PHAK and found this phrase: "In the event of complete (hydraulic or electrical) power unit failure, movement of the control surface can be effected by manually controlling the control tabs" (4-46).

Why didn't the pilots of the United Flight 232 have a backup manual control when their hydraulic system failed? Is it because the aircraft (DC-10) was equipped with three independent hydraulic systems, which were considered to provide adequate redundancy for emergencies? Then, what about other modern passenger jets like Boeing and Airbus models? Do they have a backup manual control system in case of such a hydraulic or electrical control system failure?


texts: How do you calculate coefficient of drag at an angle?

texts:
I am trying to make a simple 2d drag simulator for an object in freefall with an x and y component of wind. If I knew the coefficient of drag on the bottom and side of the object could I use theta to get the approximate CD at an angle?

Probably and oversimplified function but something like:

$CD_{\theta} = CD_{bottom} + (CD_{bottom} - CD_{side})*\frac{\theta}{\pi/2}$


texts: Why is EGT decreasing on a jet engine when the generators cut in (take over)?

texts:
Is the EGT decrease related to the generators cutting in or is it related to the fact that the fan is now providing enough ventilation air for the engine?

When I say cut in I mean that the engine driven generator has taken over in supplying the electrical load from the APU driven generator.


texts: What should I look for in weather reports in order to pick a day for glider flying?

texts: I understand weather can change unexpectedly, and local sky condition (e.g. cloud types) can't be predicted, but if I want to fly glider at a specific location, say, some time next week, and use weather forecast to pick the best possible day, what should I look for? e.g. "Cloudy" vs. "partly cloudy" vs. "overcast" vs. "sunny", is one preferable to another? (I wish the forecast would say something like "Cumulus clouds abound")


texts: Can I wear a helmet camera in an open cockpit?

texts:
When flying an open-cockpit plane (specifically a Tiger Moth):

By Towpilot (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons

Where helmets are worn, what precautions or certifications need to be observed to mount a small video camera (such as a GoPro) thereto, if it's even possible? Obviously it would be very bad if the camera were to come undone in flight, and there might be an effect on the helmet's impact protection, so my guess would be that it's simply not allowed, but perhaps it can be done if certain conditions are met.


texts: Why were the fronts of the Messerschmitt Me-109 painted yellow?

texts:
After seeing the movie Dunkirk I learnt that the Luftwaffe didn't actually use the yellow coloring on the Me-109 until a few months after the battle of Dunkirk. Was this perhaps done to avoid friendly fire? I'm eager to hear other possible explanations.

Thanks!


texts: How to command autopilot to start a fixed rate descent?

texts: Is it possible to command an autopilot to start a fixed rate descent? For example to avoid weather during the cruise phase? From what I have read the autopilot would maintain constant speed and altitude until interrupted but havent found a fixed rate descent function.


texts: Is this calculation for the 'free' climbing speed when flying in a headwind with a gradient correct?

texts:
From energy considerations, it can be found that a plane flying straight and level, if it enters a headwind with a positive gradient, will climb, extracting energy from the wind gradient.

The extra energy involved will be

$E_{EXTRA}  = mg(h_f – h) = \frac{1}{2} m (vfg^2– vg^2) $

where $m$ is the mass of the plane, $h$ the initial altitude, $h_f$ the final altitude after the climb, $vfg$ the speed of the plane (when starting the climb) in relation to the mass of air present at the altitude where the climb will end, and $vg$ the TAS of the plane when starting the climb.

Now, the question is what the extra power of that airplane will be when climbing under those conditions. It’s clear that there is an extra power, since energy is being taken from the wind gradient at a given rate…

As that rate is related to the magnitude of the gradient, we may say that, for a given wind gradient $ß$, the extra power $P_{EXTRA}$ will be:

$P_{EXTRA} = E_{EXTRA} · ß$

$P_{EXTRA} = \frac{1}{2} m (vfg^2 – vg^2) ß$

Knowing the power, we can now find also the extra vertical speed w of the plane of mass m due only to the gradient:

$w = \frac{1}{2} m (vfg^2 – vg^2) ß/mg   =  (vfg^2 – vg^2) ß/2g$

In order to 'test' the formula, we may think that the difference between the wind speeds at the top and the bottom of a 'block of wind' is $12 m/s$, that we fly with a TAS of $vg = 60 m/s$ and that $vfg = 72 m/s$. We set the gradient at $10 m/s/100m = 0.1 s^{-1}$. Thus, the height of the ‘wind block’ will be 120 m.

Then,

$w = (722 - 602) · 0.1/2 · 9.8  = 8.08 m/s = 1591 feet/min$

Not implausible, I think…


texts: What are the differences between a slot and a slat?

texts:
If you look at image 5-18 in the PHAK Chapter 5 about leading edge lift devices you see this:

However the paragraph preceding it states

  High-lift devices also can be applied to the leading edge of
  the airfoil. The most common types are fixed slots, movable
  slats, leading edge flaps, and cuffs.

So is this a typo? Should the image say 'movable slat' instead of 'movable slot'?

This leads into my main question which is, what are the differences between a slat and a slot? If I were to get asked this by an examiner what would a good response be?


texts: When is a 100-hour inspection required if alternating commercial and private use?

texts:
First, a setup rehashing common knowledge: A plane owner, who's also a CFI, gets an annual done on his Cherokee and teaches out of it for 100 hours in three months. He flies it to a repair shop 3 hours away for a 100-hour check. After the 100 hour check is complete, he can legally use it to teach for 97 hours before the next 100 hour is due (if he doesn't reach a required annual first). This is because there's a 10 hour window past the 100 hour limit to fly a plane to a place where it can receive its 100 hour service, but that window doesn't add to the time of the next 100 hour time requirement for commercial use.

Now to my questions. In the above scenario, does the 10 hour window even apply to the owner? He's flying his plane non-commercial, not for hire, so in that capacity he should be able to fly it as long as he likes (until the next annual is due, of course).

What if the owner in the above scenario teaches out of his plane for 100 hours after the annual, stops teaching and flies his plane personally for 50 hours, then decides he wants to teach in it again? Can he get a 100 hour check to get the plane legal for commercial use? Is the next 100 hour due in another 50 hours? What if instead he flies it personally for 100 hours after the 100 hour is due? Does that mean he has to get two 100 hour checks done in a row to use it commercially again? Or does he have to get a full annual to reset the 100 hour clock?


texts: Is it legal to make a non-military stealth plane?

texts: Just as military camouflage can be legally worn by civilians on most jurisdictions (e.g., in the U.S.), can I create a stealth aircraft for non-military use? More precisely, can I register and fly the thing?


texts: Is it normal that an ELT activates during a strong up draft in flight?

texts:
I was flying a PA 28 181 Archer on a nice clear day at cruise speed level flight 3000ft. Suddenly, from nowhere it was hit by an up draft that lasted I would  say less than a second. I got pain in my back. Then I noticed that the led in the RCP of the ELT (Kannad 406 compact AF) was triggered.
Is this normal? Did anyone experienced anything like this?
Should I take the unit to the repair shop? It is only 3 years old.


texts: Why do modern fighter aircraft still use transparent canopies instead of cameras feeding imagery to screens?

texts: The F-35 loves to boast about the HUD letting pilots see 'through' the aircraft, but I was wondering why they even have a transparent canopy instead of embedding the pilot deep in the fuselage like the BAe P.125 (https://www.reddit.com/r/WeirdWings/comments/b240pq/bae_p125_the_cancelled_british_equivalent_to_the/)?


texts: Could compressor stalls be caused by air in supercritical conditions?

texts:
It is likely that in compressors of jet engines appear conditions that cause the intaken air to become supercritical, cf Is the air in a jet engine supercritical? .
Is it possible that supercriticality of the fluid (air) is one of the causes for compressor stalls or compressor surge ?


texts: What does shimmy in nose landing gear mean?

texts: While I was reading a small article on "Reasons for RTO", I came across a situation where the pilots aborted takeoff because of "landing gear shimmy". What does that mean?


texts: What API can I use to get FAA NOTAMS or will this one I found work?

texts:
I am not sure if this is the correct place to ask this because it has to do with APIs with XML/JSON/SOAP, but it also has to do with aviation.

I am in dire need to find an API associated with the FAA to get NOTAMs for areas and airports. NOTAMs are Notices to Airmen, and it will be a useful feature in a service I am creating.

I have done extensive searching for a NOTAMs API, but I cannot find anything except this:
https://notams.aim.faa.gov/notamWFS/

However, this website requires registration which is just a broken link. Any suggestions on how to use this?

Do you know of any other NOTAM APIs available?
Also, if possible, do you know of a weather API which has the same information included in an ATIS/AWOS reporting station?

I was able to find working APIs for US regulations and general weather (not specific enough) and pilot information, but I cannot find any for specific weather or NOTAMs.

EDIT: A friend of mine was able to click the registration button, and it didn't give him an error. He sent me the link and I am now trying to register on the site I found.


texts: What kind of aircraft may land on iced areas, like Antarctica?

texts:
I know some aircraft may land on iced surfaces. what are the difficulties associated and is this limited to specially designed aircraft.

Is there some conditions necessary for the landing and the next takeoff.
Where are the main iced airfields currently active?


texts: Traversing a tall suspension bridge during low overcast

texts:
Suppose a pilot is flying VFR with excellent visibility and calm wind but with a ceiling of 1000, along a wide river at 500 feet. At some point she approaches a suspension bridge. Climbing and trying to cross in between pillars would be illegal due to getting too close to the clouds.

Now, would it be illegal and/or be considered excessively hazardous to fly under the bridge assuming that the vertical clearance above the river is around 300 feet?


texts: Why don't pilots control window shades & seat recliners?

texts: Every time before landing or take off, the cabin crews continuously remind passengers to pull up the window shades, straighten their seats and what not. My question is why can't pilots be given control of these things, at a flick of a button they can open / close all window shades and upright all seats. It's 2015 not 1980.


texts: Did these pilots break any regulations by hand-flying an A320 for most of the cruise?

texts:
A couple of days ago, I flew with a popular budget airline within Europe. The aircraft was an A320. It was also a brand new one (only in service since June 2018 and produces 15% less noise and fuel emissions than previous models, or so they told us).

Anyway, onto the question. During the flight, I asked a member of CC if I could meet the pilots after landing, they asked for me and the pilots agreed. They seemed happy to have a chat, I asked them how much hand-flying they had done on the 3 hour flight we had just completed (after reading on here the average for this type is 3 - 7 minutes per flight). The captain sheepishly grinned and pointed at the FO...I turned around and he was laughing. The captain then told me that since the weather was so nice, the FO, who was still fairly new, asked if he could take control. Turns out he ended up hand-flying most of the cruise!

The captain then assured me that pilots don't use passenger flights to 'practice' their skills however, and that it was actually permitted and encouraged by this airline.

I thoroughly enjoyed the 'insider' knowledge of that flight and didn't mind one bit whether the pilots chose to use auto-pilot or not, but my question is - was this actually permitted? I have read, on this site, that the A320 has specific instructions in the manual that pilots must engage auto-pilot after 10,000 ft until approach.


texts: What are the advantages or disadvantages of a mid wing design?

texts:
Are there advantages or disadvantages to a mid wing design for a monoplane? If so, how would this design compare to a high wing or a low wing monoplane design?

What might be the aerodynamic advantages or disadvantages?
What might be the design or structural advantages or disadvantages?
What might be the control or flight characteristic advantages or disadvantages?


texts: How do you maximize an electric engine's thrust?

texts:
I've been recently looking for answers to this question on the internet but the jungle of propellers, fans and electric motors didn't quite get me an answer.
How would I have to design an electric engine to produce as much thrust as possible on an area as small as possible, so the thrust/area ratio should be high. Also, assume there's enough power available.
Would I use propeller and if so, how many blades?
Would I use a fan like the turbofan of a jet engine?

With the optimal solution, which thrust do you think a 500 mm prop/fan could produce?


texts: Is it safer to do a regular approach than a short approach?

texts:
All things equal, from a standard traffic pattern at a towered airport, is it safer to do a short approach when approved by tower, or a normal one? Assume a Cherokee, Cessna 172, or similar small trainer.

My gut is a short approach should be safer, because I stay closer to the airport in case something goes wrong and I can let up on the decent rate if I hit unexpected wind shifts. However, I descend at 1000fpm in a slip, instead of 500fpm with my nose pointing to the runway. The workload also tends to be higher because there is less time.


texts: Where is Ronda's airstrip, or why does Ronda have an airport code (RRA) if it has none?

texts:
I'm puzzled by Ronda, Spain having an airport code.  Ronda has no airport.  I've never seen an airstrip anywhere near either,

Wikipedia notes that some railway stations have IATA codes, but notes that The IATA codes for railway stations normally begin with Q, X or Z, except when the station shares the code with an airport.  So according to the IATA codes it does not refer to the railway station.  ITA Matrix does not know RRA.

The tourist website andalucia.com includes Ronda in a list of unsurfaced airstrips, but uniquely without coordinates.  Other websites place the airstrip in or near the city centre of Ronda, which is untrue, as a topographic map confirms.

Does Ronda have an airstrip?  If yes, where?  If no, why does it have an IATA code?


texts: What is the relation between maximum airspeed and engine power?

texts:
I know that the drag force on an airplane scales as (velocity)^2 which implies that doubling the airspeed will produce a 4x increase in the drag force. So my question is:

Imagine we have an airplane that flies 100MPH on 100HP. If we replace the engine with one that produces twice the power (200HP) I would anticipate that, everything else being equal, the most speed increase I could possibly expect would be (100MPH) x sqrt(2) or about 140MPH- and that if I wanted to double the airspeed I would need a 400HP engine. Is this correct?


texts: How does take off mass impact induced drag?

texts:
In this answer to another question, it was stated that:

  Take-off mass: If you take no payload, the aircraft will produce less induced drag and reach a slightly higher range

How does a change of weight inside the same shaped container increase induced drag, since the air doesn't come in contact with the cargo?


texts: Can thermals or high density altitude improve fuel efficiency?

texts: Suppose a pilot is just cruising around building flight time. In order to get the most flight time for fuel, would flying on a dry cold day or on a hot thermal filled day save fuel?


texts: Can an N registered aircraft operate scheduled service from USA to/from a Category 2 country?

texts: Am looking at economics of a scheduled service between Honolulu and Tarawa but need an N registered aircraft to do it.


texts: How does a CVR / FDR determine when to stop recording?

texts:
For example, the CVR records only about 2 hours of data.

Overwriting important data must be avoided, and thus the recorders should know if a catastrophe has happened. Then they can stop recording (to protect the already recorded data from overwriting), and start signaling the rescue team.

What is the logic used to stop recording?


texts: Can drone with two propellers above one another fly vertically upward without spinning?

texts:
Basically, like the propellers setup in this image without the tail end bit:

Where the propellers will be spinning in opposite directions. This would, in theory, counteract the angular momentum to a degree right? So would this be able to fly vertically upwards without spinning?


texts: Do U.S. aircraft carriers still include a Marine Corps squadron?

texts:
When I was in the 3rd Marine Air Wing back in the early 70s, there was one Marine Corps squadron on each navy aircraft carrier, but on some shows I've seen recently (mostly on the Smithsonian Channel) I haven't noticed any Marine Corp aircraft. This leads me to wonder if they're stilled deployed on the carriers.Edit: I found this picture in the 2018 Marine Aviation Plan
Notice the "VMFA-251" marking on the fuselage. This would make it a Marine Corps aircraft. Just above the picture is this blurb:

  The F/A‐18A‐D community continues combat operations for the sixteenth straight year as Hornets support Operation INHERENT RESOLVE: Landbased with SPMAGTF‐CR and shipboard on aircraft carrier deployments as part of our TACAIR Integration (TAI) commitment.

This certainly implies that some Marine Corps aircraft are deployed on some aircraft carriers, but not necessarily all of them.


texts: Why does Schiphol airport have such a long taxi way?

texts: I heard that from runway 18R-36L the taxi time is around 20 minutes, I heard that this runway was built and is used mainly to reduce noise pollution, but what reasons are there for the length of the taxi?


texts: What are the tools that aid accurate tiller-steering in large airliners?

texts:
Airliners often need to make rather tight turns at airports. It's difficult enough maneuvering around small obstacles in a car if they can't be seen, and that's with the benefit of a good awareness of the positions of wheels, good visibility, etc. This must be much more difficult in an airliner.

For example, at a T, how do you know how far you need to stick your nose into the grass before you start turning, to keep reasonably close to the centreline? Is it just a matter of expertise and experience, or are there hi-tch gadgets or maybe lo-tech marks and sight-lines which help maneuverer these elephants around?


texts: Is a TCAS capable of handling three (or more) planes on "crash course"?

texts:
I asked myself if the TCAS is capable to handle, the very unlikely situation, that three (or more) planes are simultaneously on "crash course" (Sorry, got no other word for it).

If not, how would the TCAS "react"?

Thanks.


texts: Is an 400+% increase in lift with distributed propulsion realistic?

texts:
Is an 440% increase in lift with distributed propulsion realistic?

I understand NASA swapped out the wings on their test plane with distributed propulsion from 17psf to 45 psf.  That's a factor of 2.6, which is an increase in efficiency of 260%!!

If the original wings have a cL of: 50% classic airfoil cL max of 1.5 + 50% slotted flap cl max of 2.7. that works out a wing cL max of about 2.1

So... cL of new wings must be a cL of 2.1 x 2.6 = 5.5, or an increase in cL of about 3.4.

S0... if I start with a foil like the Selig1233, with a max cL of 2.5, a slat adds .7 plus 3.4 for distributed propulsion, I'm looking at a total cL of 6.6.

A cL of 6.6/1.5 is a 440% increase in lift.

Is this realistic?

If not, what is?

Use would be for a small ultralight, max speed about 60mph.


texts: What are these shaded areas? I looked in the Jeppesen legend, but couldn't find the answer. Thanks


texts: What work besides flying planes does an airline pilot regularly do?

texts:
What are the typical non-aircraft duties for an airline pilot?

By non-aircraft, I'm asking about time spent in the office, in meetings, training (whether in a simulator, class or other non-aircraft environment), deadheading or being at the airport but not actually in the aircraft.

I understand there is paperwork and pre-flight planning done on the ground between flights while in the cockpit, so I'm not asking about this. I'm really trying to get an idea about what other work related activities you do which does not involve you being in the cockpit (except perhaps purely as a work-related passenger).

Another way of asking this question would be, "what work besides flying planes does an airline pilot normally do, or might reasonably be expected to do, as part of his or her job?"


texts: What are the elements of an approach briefing?

texts:
I've heard that before landing an airliner, the pilots perform a mini-briefing to agree on what they will do and what they can do if something goes wrong during the approach and landing.

Is this true?
What is it called? (my best guess would be "approach briefing")
What elements does the briefing contain?


texts: Will helicopter control inputs be reversed because of precession if the fuselage starts a rapid spin?

texts: My question stems from a loss of tail rotor effectiveness. If a helicopter with a counterclockwise rotating blade like the R22 loses the tail rotor and the fuselage starts a rapid right turn and thus gains momentum, will the control inputs be reversed or will it create a double gyro from the main rotor system  and cause control inputs to be normal?


texts: Why do modern airliners have windscreens which open?

texts:
I'm sure it must be nice for pilots on a hot day to pop open their windscreen while waiting on the tarmac, but is there a good engineering or safety need for them? There must be a significant amount of cost and time effort in making a windscreen both openable and safe. If the pilots really need some fresh air, they're usually pretty close to the passenger door.

I can imagine there were valid historic reasons for having them: when planes were smaller and instrumentation not so sophisticated, you might literally want to take a proper look at your propellers spinning before setting out. But why do we persist with them?

737 Max with both its cockpit windows open source

Airbus A380 with open window source


texts: What kind of input is used by NASA's TASAR?

texts:
I've found the Aviation SE to be a really interesting read so far, I'm excited to be here! I'm fairly new, but I'm also old!

What are the inputs for TASAR to crunch flight path optimization? Is it taking a look at the aircraft performance model, wind and weather, and ADS-B IN? Maybe TCAS-II traffic info? Would the weather data come from the onboard WXRadar or ground data?

I've read a few data-points that the long range weather info pilots tend to use is from received data (maybe ground radar or sat based weather data? both?), but the data is delayed to the point of being less useful, would the weather data need to take inputs from both Weather RADAR and NEXRAD type inputs?


texts: What are the considerations for landing on ice runways?

texts:
In Greenland there are a number of ice runways and I have heard that it is no difficulty landing on them. One would think they would be slippery and the aircraft might slide off the runway or ground loop. However apparently that does not happen.

Are there any special considerations for landing on an ice runway? Is there an increase in minimum landing distance?


texts:
If someone with no night vision were in the cockpit of a nocturnal flight, that person's situation would resemble Instrument Flight Rules. Am I correct? So:

In theory, can someone lacking night vision operate an aircraft with no more danger than a pilot on IFR?

Can someone lacking night vision get a pilot's licence?

An answer that is valid for India, China, EU or the US is appreciated


texts: Main structural (and any other) impact of hard landing

texts:
I was reading this question related to the parts suffering the most G forces. Reflecting about that question I question myself about hard landing, which is not a normal operation.

So, my especific question is: when an airplane is suffering a hard landing event, which are the structural parts (and any other part that might not be structural and I might be forgetting) that are suffering the main damages and why?

Will this answer depend on the airplane vibration mode (i.e. location of engine masses)?


texts: Are same-era military aircraft cockpits designed to be familiar to transitioning pilots?

texts:
The wonderful SR-71 ha what looks to me an intimidating cockpit:

However, lots of planes of that era have ostensibly-similar cockpits to the layman, take this F-5 for instance:

I choose the F-5 as it was flying around the time the SR-71 was introduced, and thus potential SR-71 pilots may have been familiar with it. Would the cockpit designers have taken this into consideration? In general, are next-generation airplane cockpits designed to be familiar to pilots of current-generation aircraft?

Elements that may or may not be taken into consideration:

Placement and relative placement or grouping of instruments
Size and relative size of instruments
Lighting, colours
Calibration
Materials selection


texts:
From this Wikipedia article

  A fighter pilot based at Andrews Air Force Base, Billy Hutchison, claims that while in the air he spotted Flight 93 on his scope and planned to first fire his training rounds into the engine and cockpit, and then ram the airplane with his own jet.[135][136]

One of the references refer to these as "practice rounds".

What are practice rounds? Are these a special type of ammunition with inferior performance to standard ammunition for the M61?

From the M61 article I found that these rounds appear to exist: "PGU-27 AB training rounds"

Are these the correct rounds the plane was supposedly loaded with?

The article seems to claim they are both cheaper and more effective than standard rounds, but maybe I'm reading it wrong.


texts: Why is there such a low level of automation in the aerospace industry (compared to other industries such as automobile)?

texts:
I have been watching some episodes of the documentaries made by National Geographic lately and I have noticed something that I can't find an explanation for.

In this episode of Megafactories - Eurofighter Typhoon, starting at 17:21, the amount of automation in the factory is apparently very low and the workers seem to be doing everything with their hands.

On the contrary, in this episode about the Volkswagen factory in Wolfsburg, starting at 24:05, the process is much much more automated and there is almost no one around doing anything by hand.

I have always thought that the aerospace industry is one of the most sensitive industries and the highest levels of accuracy, precision and consistency are required. But those documentaries show the opposite to this.

So is there a reason as to why this Eurofighter Typhoon factory is so much less automated than this Volkswagen one? Is there something I might be missing that would make a less automated factory a better choice for the aerospace industry?


texts: Why don't airliners use noise cancelling?

texts:
Some cars have started using noise cancelling in their cabins, through the speaker system. It's a well established technique for dealing with low frequency noise like engine rumble and wind noise.

So why don't modern airliners use it?


texts:
Was interesting to watch the explanation about glider here, especially about the glide ratio. Glide ratio is defined as the ratio between altitude when it start gliding (Y-axis) to the distance it can reach until the altitude reach zero (X-axis), as shown in the picture 2. Gliding is a descending, opposite of climbing, which is ascending. All airplanes are designed to be able to glide to anticipate the worst case when the engine is failure.

There are many discussions how to calculate an airplane when ascending, explains the relation of wing area, wing ratio, airplane load, initial speed (velocity), and the power it requires to meet the ascending rate. Then my question is, how do I bind such that information when calculating the glide ratio/distance?

Edit:
I believe the weight of the airplane contributing the glide distance (ratio) it can reach. Just consider two identical airplanes (say it Cessna 172), one is fully loaded and another one is not loaded at all (except the pilot, of course). They fly at the same speed and turned off the engine at the same time.

Also consider two airplanes (also Cessna 172) with exactly same weight and load, but fly at different speed and then turned off the engine at the same time.

From both above illustrations, we know their momentums are different. Is not the momentum contributing to the glide distance (ratio)?


texts: How can someone get clarification from the FAA on the intent of a regulation?

texts: How does someone request a letter of interpretation from the FAA if a particular situation surrounding a regulation or policy is not clear?


texts: If there is a misprint on an instrument plate, is a pilot required to comply with it?

texts:
This is a snippet from the KESC RNAV 36 approach.  It's a real procedure, I didn't photoshop it except to add highlighting.

Let's say I was in the position that the blue aircraft is in (roughly 10 miles from WOKOL bearing approximately 320), and I had been cleared to WOKOL for the RNAV 36. I am assuming ATC did not explicitly tell me to do a procedure turn.

What am I supposed to do when I get to WOKOL?  The plate says NoPT, which is obviously a mistake.  Do I still fly the course reversal?  Do I whip into a 150 degree left turn over WOKOL as illustrated?

Here are some relevant passages from the AIM:

AIM 5-4-9:

  The procedure turn or hold-in-lieu-of-PT is a required maneuver when it is depicted on the approach chart, unless cleared by ATC for a straight-in approach. Additionally, the procedure turn or hold-in-lieu-of-PT is not permitted when the symbol “No PT” is depicted on the initial segment being used, when a RADAR VECTOR to the final approach course is provided, or when conducting a timed approach from a holding fix.

AIM 5-4-5 (D. 2. b.)

  The published procedure will be annotated to indicate when the course
  reversal is not necessary when flying within a particular TAA area;
  e.g., “NoPT.” Otherwise, the pilot is expected to execute the course
  reversal under the provisions of 14 CFR Section 91.175. The pilot
  may elect to use the course reversal pattern when it is not required by the procedure, but must inform air traffic control and
  receive clearance to do so.

If an instrument plate contains errors, am I still required to comply with them?


texts: On crosswind landings, is it preferable to side slip or crab on final approach?

texts:
I've seen several instructional videos on crosswind landing techniques.  Some advise the pilot to crab the aircraft until just before touchdown when he/she should kick the rudder over to align the aircraft with the runway centerline.  Others advise the pilot to slip the aircraft all the way down so that no other cross control maneuver is needed.  Many of these videos also acknowledge the other way of doing things but say that their method is superior.

Is there an accepted "safer" method for flying a final approach with a crosswind or is it an entirely personal preference?


texts: What is the optimum design: elliptical lift distribution or elliptical span loading parameter distribution?

texts:
I am getting very confused with these terms. I'm trying to analyse a span loading  distribution given as cl(y)c(y)/ccL. This distribution is almost elliptical but when I plot just cl(y) it changes and I have more cl near the tips due to the reduction in chord.

This made sense from my point how view since the AR is low, the sweep is high and the taper ratio is small. It is like the figures I remember for these cases. However, when I have searched in google I have seen this image:

This wing is pretty similar to mine, and the distribution is similar to my cl(y) distribution. However, the parameter here is cl(y)c(y)/ccL!!

I don't understand completely the difference. When we talk about elliptical distribution for minimum induced drag it is about cl(y) or cl(y)c(y)/ccL? Why is this parameter used and plot and not cl(y)?


texts: What was the first production jet engine to use a semiconductor based control system?

texts:
What was the first operational jet engine to use a control system containing semiconductors? This would include analog systems as well as digital ones. I am assuming that analog ones came first.

This would have to be a component used for normal operation of the engine, it would not include any equipment used for maintenance or diagnostic of the engine while on the ground.

Additionally it would have to be an aviation jet engine actually installed in aircraft that flew. Not just an engine used for R & D purposes on the ground.


texts: What are those things under the Concorde’s cockpit windows?

texts:
I’ve noticed there are little bits sticking out under Concorde’s cockpit windows and they’re too small to be canards. Are they some kind of vortex generator or something?

(Source)


texts: Where to find historical locations of North Atlantic Tracks?

texts:
I'm looking for historical, daily locations of the North Atlantic Track (NAT, published daily as NOTAM) system for the past 10/20 years.  I've already contacted what feels like dozens of organizations (FAA, Gander, Shanwick, ...) but no-one seems to actually archive the NAT locations.

I'd be extremely grateful for any pointers towards possibilities to acquire these data, be it free or paying.


texts:
In this AVWeb article, numerous references are made to 500 and 1, with other references to 3,000 and 5.

Based on the statement The current observation was 800 overcast and four miles visibility (in the second paragraph), I would presume that 500 and 1 means a 500 foot ceiling and one mile visibility, is that correct?


texts:
On average, how many landings does a student pilot need before their first solo?
I know it depends on individual students, but roughly what is the number?
Or you can just tell me your experience.


texts: How to not converge or diverge from the runway when there aren't checkpoints?

texts: When flying circuits under VFR, if there is no clear distinct checkpoint available, what can you do/use as a checkpoint? I suspect the runway but please correct me if I'm wrong. How do you make sure you don't converge, diverge from the runway or stray away from the centreline?


texts: Why do airplane indicators start at 12 (o'clock), unlike cars that start at 7?

texts: A car's speed and RPM indicators usually start at 7, lower left, but airplanes' altitude and airspeed indicators start at noon. What's the origin of this convention?


texts: How much does the landing gear compress on a fully loaded airliner on the ground?

texts:
When an empty airliner is loaded with passengers, cargo and fuel, the extra weight compresses the gear strut and it sinks. Jet bridges are designed with this in mind.

How much height does it actually sink?

For the purpose of the question, I am interested in any typical commercial airliner models.


texts: Why does the Hinch Mountain VOR (as an example) have void areas below certain altitudes published in the U.S. Chart Supplement?

texts:
I was digging around the SE region Chart Supplement, and I was reading KSRB (Sparta, TN), and this "VOR unusable" listing is contained in it:

The sectional chart shows that it is nearly on top of a hill. I've made some visual marks on this to help everyone visualize.

Hench Mountain is a Low Altitude VOR, so by normal standards, service should be clear all the way around at 1,000 ft above it's altitude:

Why are there unusable areas more than 1,000Ft above the elevation of the VOR?  I've flown over it, and there are no obvious obstructions, it sits on top of a flat hill as you can see in this video I found on Youtube.


texts: What is the difference between Mechanical Engineer and Aerospace Engineer?

texts:
I really want to get into the Aerospace Engineer industry (I want to design the plane's airframe and basically a little bit of everything) but have no idea what to major in for any job.
I'm really thrown off by all these sites which have mechanical engineer and aerospace engineer jobs but they consist of basically the same job description.
Can you please clear this confusion for me?


texts: Are the items in newbie "kits" actually used during or after training?

texts:
I want to start training for my Private certificate but I do not want to waste my money.  I'm already purchasing an online course for ground school.  Generally speaking, are the following used during or after training?  And, if so, would a $150 US price tag be worth it?

Electronic E6B Flight Computer
FAA Aviation Weather Text Book
FAA Airplane Flying Handbook
Private Pilot Maneuvers Guide
Pilot's Handbook of Aeronautical Knowledge
Pilot's Log Book
FAR/AIM Fuel Tester
Flight Gear HP Crosswind Bag
Sectional Plotter
VFR/IFR Flight Plan Forms

Thanks, in advance.  I'd rather spend my money on flight time than nonsensical items.


texts: Where do standard torque values in maintenance manuals come from?

texts:
Maintenance manuals of today's civil aviation aircraft (from both Boeing (e.g., B-737) and Airbus (e.g., A320)) have special chapter to describe "standard torque value" for fasteners and connections. These values are determined by material, size, etc.

I wonder where and how these values come from. Could anyone provide me with detail about this?


texts: How common are missile defense systems on civil airplanes?

texts:
I've just stumbled upon Why don't El Al 747's stay at the gates at JFK? in the hot topics.
I kind of get why El Al decided to put missile defense systems in their planes but I was wondering: How common is this? Are there other airlines who do this?


texts: Which light aircraft are known to have a quiet cockpit?

texts:
Are some light aircraft known as being significantly quieter in the cockpit than others ? How quiet might the quietest light aircraft be from the inside ?

At least ten years ago I was reading an aviation magazine and there was an article about someone who had gone all out to make their aircraft cockpit as quiet as possible. I can't remember the details but they'd made a whole lot of modifications with sound reduction in mind.

Ever since then I've wondered: are some light aircraft really noticeably quieter than others (and do they get sold on the basis of them being quieter) and is modding your aircraft to make it quieter a common thing ?

(I am of course referring to closed cockpit aircraft, I appreciate a Gypsy Moth would inevitably be quite noisy !).


texts: Can an AFSP training request be renewed when the current one has not yet expired?

texts:
My Alien Flight Student Program (AFSP) training request expires in about two months, so the aviation school I'm learning with asked me to just go ahead and create a new training request so there's no wait time between my current request expiration date and whenever the new one would come in.

However, I cannot find an option to create one when the current one is active looks like.

Can you apply for a new training request before the current one expires? If so, how many days before?


texts: What can cause my radio to transmit nothing but a terrible noise?

texts:
I have replaced the noise filter and checked the jacks. It does not matter what headset or jacks are used. I replaced the audio panel and had the radio serviced. When I transmit all I hear is a low screech. Others simply reply to transmissions with a simple I cannot understand anything.
Two people can talk inside the airplane with no noise and reception is clear. I have also checked voltage and connections going to the radio as well as installed a new high quality line filter. Both push to talk switches cause the same noise, I have tried flipping things on or off running the trim etc. no change.


texts: Is it safe to takeoff with some ice and snow on the wings?

texts:
I took a look at the post 'What things can a passenger look out for, to indicate an emergency?', and remembered this video I've seen.

Obviously, video uploader claims that this take off was unsafe due to some ice and snow on the wings. Was he right? Were the pilots really breaking any regulations?


texts: Is it possible to play music in the cockpit?

texts: I was wondering that if a pilot's flight had been delayed or a pilot had nothing to do, would it be possible for a pilot to play music in the cockpit?


texts: In an engine failure, should I expect less range than with the engine in idle?

texts:
I fly a C172 (fix pitch propeller) and when my instructor and I practice a simulated engine failure, we do not turn off the engine, instead we set the engine to idle.

In an actual engine failure, should I expect less range than with the engine in idle?


texts: What are the rules in the UK about overflying built-up areas for fun?

texts:
I live in North London.  It's not like we don't have a fair amount of noise pollution from the sky, with helicopters, and jets landing at LHR with a stupidly shallow glide path angle.

But in addition, quite often on a Sunday afternoon I hear this buzzing of a small propeller plane.  It often seems to circle the area quite a few times before eventually going away.  We had one today: I looked at it, and (this time) it was a small plane with two props, one on each wing.  I have no idea what type of aircraft it might have been.  It was flying low enough for the buzzing to be distinctly intrusive, and therefore affecting potentially tens of thousands of people.

It may not have been a flight simply for fun. I presume there's no way of finding out... but does anyone know what the rules are for just randomly deciding to fly over a built-up area like this for the fun of it?

PS I have friends in Cambridge and you often see small light planes overflying that town. They have a friend who owns a light aircraft, and once or twice my friends have said "oh, yes, that's Jim's plane", and have confirmed he does it for recreation.


texts: How might one obtain aircraft registration numbers for past flights (months ago)?

texts:
I am trying to obtain tail numbers for some flights to retrospectively complete my 5 month old's new passenger flight log book. Antonakis, FlightRadar24 and FlightAware sites are not giving me the answers since the flights took place too long ago.

This is the flight information that I have:

Flight No.    Date          Route

AC 8036       29/10/2015    YYZ-PIT
AC 8037       02/11/2015    PIT-YYZ
AC 7508       05/12/2015    YTZ-YUL
AC 7521       12/12/2015    YUL-YTZ

Any help or instructions on where to obtain info would be greatly appreciated.

Note that this question is not a duplicate. This question is not answered by the question, How to determine the aircraft tail number on a particular flight?, since these flights occured too long ago to be found through the methods discussed in the answers to that question.


texts: Are there any photos or videos of the drones at Gatwick?

texts:
The Gatwick Airport drone incident from 19-21 December 2018 involved "67 reports of drone sightings close to the runway" (Wikipedia).

However, police stated there were no photos or videos of the drone (The Guardian, 23 Dec.).  Later, police said that statement had been the result of "poor communication" (The Guardian, 24 Dec.).

Regardless, I haven't found any photos or videos of the drones.  Are there any?  If not, why not?  Were they too small (or far away) to be seen by a cellphone camera?  But then how could humans see them?  How can 67 people see a drone in this day and age and none of them record it?  Is it plausible that there actually were no drones?


texts:
Recently, there's been a lot of coverage in the news of drones disturbing operations at airports.
Do airports have a method to detect drones? If yes, how does it work? If it's still an emerging technology, is it something being looked into?


texts:
I'm a Chemistry student preparing an in-class lab demonstration that involves the combustion properties of jet fuel used in typical US based airliners.

Is all jet fuel the same, or do I need to consider specific blends when designing my experiment? Is there a standard chemical formula for jet fuel?

And for bonus points, are there any critical handling considerations?


texts: What happens when lightning strikes an airplane?

texts: What happens to an airplane when hit by lightning?


texts: What are the main factors that make an aircraft have good STOL performance?

texts:
What are some of the main characteristics and design principles utilized to make an aircraft have good STOL performance?

As a bonus, what are some disadvantages to some of those characteristics and thus reasons why they aren't utilized on all aircraft design (cost aside).


texts: What is the linkage connecting the body landing gear on the C-130?

texts:
I can't seem to find a diagram that includes this tube linking the front and rear body gear on each side. Is it structural, or hydraulic, or maybe something else entirely?

Image source: https://www.airport-data.com/aircraft/photo/001380858.html

Additional photo: https://www.airport-data.com/aircraft/photo/001454050.html


texts: What are the pros/cons of low/forward powerplants on helicopters?

texts:
(Original)

The double-decker Westland Wessex has a pair of side-by-side Gnome turbines low and forward (blue rectangle above).

What are the pros and cons compared to the center-high more typical placement of nowadays?

Of the cons is perhaps the longer shafts I drew above, which are concluded based on pictures that reveal the orientation of the engines and pictures of a partition between (but aft of) the two cockpit seats.

I searched for clear cutaways on Google and Flight's archive. Also checked the Wikipedia page regarding the engine placement.

The Wessex is developed from the Sikorsky H-34 that had a radial engine in the same location.


texts: Before  WWII, flying boats were a popular form of transport, and the advantages are many: No need to build runways, capability of emergency landing on water, availability of large landing sites and no tire wear and tear. Why have they been abandoned?


texts: Can a wooden/fabric cover design be built of metal?

texts:
I know this question is somewhat general and could vary from plane to plane so I will elaborate on the plane in question.

The specific plane I am curious about is the Mooney Mite which has a metal center section but wooden wings and wooden rear half and empennage which at the age most of these planes are is prone to issues. It seems like a great little plane.

My question is can one be built out of aluminum to the same specs (maybe with a bigger engine) and still fly properly or will the weight change (CG change) affect the plane too drastically?

Likewise could a Piper Cub or similar be made of all metal (again with a bit more power up front) and still be an effective plane?

For the record I do not currently have plans to build this plane (although it was available as a kit plane at some point in history. I am aware of the certification issues with making alterations like to an existing plane. I was asking more about if it was possible from an aeronautical standpoint.


texts: Iris Precursor - 4D Air Traffic Control System

texts:
I just read this article . From the article at the very end -

  ESA claims that the new tech, which may eventually require an Iris
  terminal/transponder to be attached to every plane in European
  airspace, provides "4D" flightpath control. Prosaically, this means it
  provides four coordinates, locating each aircraft according to
  latitude, longitude, altitude, and time—which ESA says "will enable
  precise tracking of flights and more efficient management of traffic."

While it would be known in time whether it truly works as advertised or needs kinks to be worked out, something like this should have made events like 'disappearances of MH370' much more rarer as rescuers would have much more precise locations to search in case of any untoward incident.

The simplest way to think of it is like the radio and Uber cabs which constantly ping back to the home location so they know where the drivers are at all times. Just an expansion of the idea at a somewhat ridiculous height :)

Do people think it should improve the safety of the aircraft or it would be another tech. that is just as liable to fail as others ? Hopefully people keep an eye on this technology and where it goes. If anybody knows any similar technology, feel free to share as well.


texts:
I am 2nd year PhD student in Physics.

Can you think of any UAV project which won't contribute to army? UAV designing is a career of my dream, but I want to serve the greater good. However, all advances are developing in military field.


texts: Would it be realistic to live in an airplane?

texts:
I've been playing with the idea of someday modifying a small airplane to create a sort of flying RV/Camper. The passenger seats would be removed and replaced with a flat, raised surface that would run along the wall to be used for a bed, or a desk during the day. A small chair and portable toilet could be secured below that, with room for food, etc.
Would this be usable in practice? Can a certified aircraft be modified in this way? Is it allowed to sleep in a plane on the apron overnight? Is external power ever available near airplane tie-downs? Etc.
I'm mostly asking about the U.S., but I'd be curious about other countries as well.


texts: Can airplanes benefit from this "roughness" on bird wings?

texts:
Why do birds have so much rough surface (overlapping feathers) compared to aircraft? Isn’t that cause additional skin friction drag?
Could planes maybe benefit from this?
link:
https://www.researchgate.net/publication/263394314_Gliding_Swifts_Attain_Laminar_Flow_over_Rough_Wings


texts: Can I check my density altitude with brake tension?

texts:
The same way one would apply the brake and accelerator, the more torque the more break is needed to hold the car, can a plane use this same technique to check the plane thrust and air density before take off?
Using a brake pressure gauge, could density altitude be measured by how much pressure is needed to hold the plane in place?


texts: How can I modify a fuselage to increase the payload?

texts:
I'm designing a regional turboprop for a university assignment. The design requirements are very similar to the Dash 8 Q400 in terms of passenger capacity (90 pax), speed, range, runway length requirements. The difference is the payload mass required is 35% greater (8,500kg to 11,500kg).
So I've sized my wings and my engines and control surfaces and flaps and they're all bigger. My issue now is the fuselage. Since the passenger capacity is the same I have less motivation to increase the dimensions.
Increasing the diameter for the sake of more internal volume seems inefficient; I don't need more aisle and armrest space. On the other hand, increasing the length (without increasing diameter) would mean a heavier fuselage structure.
Even once the fuselage is lengthened, where do I put the cargo? For the Q400, cargo holds are right at the aft and just before the cockpit. But if this is my solution I'll be shifting the centre of gravity and creating even greater bending moments.
My ideas so far are to create a  near c.g. cargo hold that would likely split seating or to utilise space available under the floor of the cabin. I haven't seen any designs that support these ideas though (for narrow bodies).
I tried to look for twin-engine turboprops with similar payloads, the only one I found was the C-27J Spartan (military transport), but it's practically designed for cargo.
Could someone give me some wisdom on how I should proceed? I've done quite a bit of reading and research but can't resolve this aspect of the design.
Here's the 74 seat cabin layout for the Q400.


texts: What made 800 feet and later 1,000 feet attractive as the standard traffic pattern altitude?

texts:
The value of a commonly understood traffic pattern altitude is obvious, but what is the history behind TPA of eight hundred feet in particular? Why not 700 or 900?

Was the later move to 1,000 AGL because of easy math only, or were there other reasons?


texts: Does airspeed affect the critical angle of attack on an airfoil?

texts: I understand that the critical angle of attack is mostly affected by the shape of the airfoil.  However does the airspeed of the airfoil or the density of the air affect the critical angle of attack?  I would think that the airspeed or air density would affect the laminar flow properties and could change the critical angle of attack of that airfoil, perhaps only slightly.


texts: What exactly are those openings in the bellies of many jetliners?

texts:
I have circled the areas (in yellow) under the belly of the 737.

What exactly are those?

(airliners.net)


texts: Why are aircraft tires not pre-spun prior to landing?

texts:
Currently, as far as I know, most modern (big) airliners do not pre-spint the tires before landing. The question is why not, as there are certain benefits. This question was asked here before Why are aircraft tires not pre-spun prior to landing to preserve them? , but I think not all benefits were mentioned there, especially not the passenger comfort.

Advantages: From most important to less:

Comfort: At the moment of touch down, the gears are fiercely slammed backwards. The passengers won't experience this any more, which ads up to their complete flight experience.
Safety: A slipping wheel has no grip, also not sideways. Also the aircraft will be more stable at the moment of touch down (see 1). When it does not work, we are just back to the currently accepted old situation. Even when it fails in the sense that the tires spin too fast!
Tires last longer: This saves money for replacing them and the saves the time to do so. Most delays I personally experienced by interim maintenance on aircrafts were by maintenance that consisted of one tire replacement only! Still most tire wear does not come from the touch down moments.

Disadvantages: From most important to less:

Costs: Of course it will come with a price and add extra weight to the aircraft, etcetera.
Control: The gyroscopic effect of spinning wheels have their influence on the behavior of the aircraft. But this problem is already there just after takeoff. Would an A380 pilot really notice?? Or is it a minor issue at takeoff that would be a major one at landings? Please tell me!
More difficult tire maintenance scheme: For each tire a log needs to be maintained of how many times the tire touched down where the system was both working and not working.

Design considerations: The system can take the time from when the gear is completely down to touch down to spin-up the tires. It is not a problem when the tires' speeds to not exactly match each other or the landing speed.

Simple implementation: Attach an electric motor to each axle of the main gears. At take-off they are disconnected, otherwise they would act as dynamic breaks. At landings they always just operate at full capacity. The size and power of these engines need just be enough to overcome slightly more than the resistance of the axle itself and should be just at the level that, after a minute, the tires keep spinning at an average landing speed (and don't speed up any more). For the (tire maintenance) logs each axle also should have a detection for if it is spinning above a certain speed, like faster than half the average landing speed.

What is the decisive reason something like this was never implemented on a modern (big) jet aircraft?


texts: Is there a downside to trying multiple flight instructors?

texts:
My local airport has a Part 61 flight school and gives students the option of selecting among three Certified Flight Instructors. Farhan and others have posted excellent explanations of characteristics to look for in instructors.

Other than wasted time and money, is there any downside to doing an "Introduction to Flying" lesson with each of the three instructors and seeing which one I like best? Similarly, am I likely to offend CFI's that I'm "looking around" other options?


texts: Can a helicopter have a fully mechanic "elevator"?

texts:
After a research, I've seen prototypes of planes with elevators. What if it could be used as part of the "Air Ambulance" technology on helicopters? Because helicopters have to land first to pick up patients, would it be better to use an "elevator" to lift them into the helicopter when it is hovering?

If this have been made before, can you point to a prototype?
And if not, why it haven't been made? Is it non-doable in terms of physics and engineering?


texts: Surface deflection if loss of hydraulics on combat jet

texts:
In a typical combat jet from the 1970ties, at loss of hydraulic pressure, how does the deflection surfaces behave?

If it happens on the runway, will the weight of the surfaces make them deflect downwards?

If it happens at speed, will they align with the incoming airstream?

I heard something about a Hydraulic lock, is such a thing common in fighter aircraft and will it make the surfaces 'freeze' at hydraulic loss?


texts: What to do when pneumatic air cycle kit stops working mid-flight on Boeing 737-800?

texts: If you are flying a B738 at FL390, and one PACK (pneumatic air cycle kit) becomes inoperable, do you have to descend to FL250? If so, do you need to divert for fuel?


texts: I’m flying on a WestJet Boeing 737-800 from Honolulu to Vancouver and then on to Toronto in July, returning on the same type of aircraft in August. Are these aircraft still grounded and are they similar to the MAX 8?


texts: When does the airline check if an airplane can reach its destination?

texts:
It is known that - for example - LaMia Airlines Flight 2933 needed to travel 1,605 nautical miles (2,972 km), which exceeds the range of the Avro RJ85 at 1,600 nautical miles (2,963 km).
At what point in flight planning does the airline calculate and determine if an aircraft has enough fuel/range for its intended flight?


texts:
I am currently reading docs regarding slots, where the following is mentioned:

All SCR messages in linked (turn-around format) using aircraft
subtypes only (e.g. 73G or 738 instead of 737).

Not sure what is meant by the above sentence. My understanding is that whenever you submit slot requests with SCR messages you need to use the IATA aircraft code as defined here.
The Worldwide slot guidelines also mentions:

Operating a flight in a significantly different way to the allocated
slot – including a different service type, aircraft subtype, aircraft
capacity, or origin/destination – without the prior confirmation of
the coordinator as set out in 8.10;

So what is exactly the difference between an aircraft type and an aircraft subtype? Does the link provided above refer to aircraft subtypes?


texts: What do those writings mean that are on the landing gear doors?

texts: I've been watching carrier videos a lot these days and I notice these writings. What do these writings means? I didn't upload all of them, most of the time there are location names and sometimes person names. What is written on those doors? This says UK, this F-18 belongs to US, this is a screen image from a video that was recorded in Naval Air Station Whidbey Island


texts: How to fill out IFR flight plan for manned helium balloon flight into class A airspace with no predetermined route or destination and less crew?

texts:
Per FAA regulations, an IFR flight plan must be filed before going above 18,000 feet MSL as this is class A airspace.  How do we fill out the IFR flight plan if the destination landing site and the route taken of the lighter than air aircraft are unknown, and one of the crew members will be disembarking in flight and parachuting down?

Note: This operator does this on a regular basis.  They use manned helium lighter than air craft, not hot-air balloons as answered on previous questions so this question is not a duplicate.


texts: Who invented the cabin chime? What aircraft was the first to use it?

texts: While looking for one to set as my ringtone, I became interested in the history of the cabin chime - the "bing-bong" noise heard on practically every commercial airliner today. I've found tons of downloads for the sound itself and a few posts by pilots and cabin crew on what different chimes or sequences of chimes mean, but nothing on its origin. Anyone?


texts: What is the encoding difference between ARINC 429 BNR and BCD formats?

texts:
I think I have an understanding of the differences between the types of ARINC word formats, but would just like to get some input to see if my understanding is correct. In the ARINC 429 specification, it is discussed that there are some differences in how messages are handled between the two formats.

Data Field

This one just seems like basic arithmetic concepts and doesn't concern me as much. From what I understand, the BCD data-field works the following way:

Data-Field = 0x12340, means that the data is actually 12,340 (twelve thousand, three-hundred-forty) in base-10.

Then, BNR data-field would work like:

Data-Field = 0x7FD1C, means that the data is actually -740 (based on two's complement arithmetic).

Sign-Status Matrix Field

The operational codes just mean different things. Or in other words, the code numbers are the same, but the codes themselves have different meanings for BCD messages than BNR ones. Now, if there aren't any other differences, I would also like to know why the op-code schemes are slightly different.

My Question

So, I guess in a single sentence my question would be: are these the only differences between the types of ARINC messages?


texts: Was the introduction of the A320 flight control system controversial?

texts:
There were multiple severe accidents briefly after the entry into service of the A320, many involving to varying degree the augmented control system as a cause. In my eyes the A320 seems to have a very aggressive manipulation of the aircraft controls historically early (1987).

Conversely, the introduction of composites of the Boeing 787 generated a lot of stir and questions about safety, repairs, and lifespan.

Was there ever any questioning of the Airbus augmented control prior to the introduction to service?


texts: Adjustment for non-balanced passenger loads?

texts:
It is well established (How Centre of Gravity (CG) is adjusted? and elsewhere) that adjustments can and need to be made to insure that airplane loading maintains a suitable center-of-gravity for the aircraft fore/aft.  However, these questions and answers appear to deal only with fore/aft adjustments.  Does a plane such as the MD-88 which has unequal seating (3 seats on the port (left) side of the aisle and 2 on the starboard (right)) have much of an issue with port/starboard balance, and if so, is there standard way of dealing with more passenger weight on the port side of center-line?

I would assume this could be handled with unequal fuel tank loading in each wing, or air surface adjustments, but am curious if in practice this is an issue or not.  Or is there anything built into the design of the aircraft to handle this expected unequal passenger loading?


texts: Are US pilots permitted to carry & use their firearm in countries where guns are illegal?

texts:
On the question of Are pilots armed?, one thing this made me think is: for the few that are armed, are they allowed to bring their weapon into, for example, the UK?

What is the procedure? Does the gun stay in the cockpit or does it need to be checked by security once on the ground?

Presuming a pilot had to fire a gun over EU airspace, is he breaking the law?


texts: Why is the reheat exhaust flame of some fighter aircraft blue while for some it is orange?

texts: Why is the afterburner flame of some fighter aircraft blue while for some it is orange?


texts: What is the purpose of a movable inlet on a jet engine?

texts:
I was reading that aircraft like the F15 and SR-71 have movable inelts. Whats the purpose of this?
I was also reading aircraft like the F-22 doesn't have a movable inlet. Why?


texts: How should private airports or locations not regularly intended for landing be identified if you land at or take off from them?

texts:
How are runways on sectional charts that are listed as private identified?

Lets say I fly from a public airport to a private strip; I would log the departure airport as BNA, but what would I list the private strip as?

Generally, what is the accepted norm?


texts: How are helicopter cyclic and collective jacks connected?

texts: Regardless of the degree of collective pitch applied, the cyclic pitch controls must retain their full range. Both controls are via jacks, so how are the jacks connected?


texts: Why are cabin doors outlined with a different color than the fuselage?

texts:
On almost all airliners I have seen, the doors are painted inside a rectangle which appear to reflect more light. This is the case whether in the aircraft has its manufacturer's paint or an airline's custom livery.

What is the reason behind this?

It can be seen in these pictures.

Image Source

Image Source


texts: For a same propeller solidity, what are the tradeoffs between blade activity factor and blade number?

texts:
In order to absorb more power for a given prop diameter, we can design the propeller with a higher activity factor-- basically what amounts to wider blades-- or we can also design it with more blades. Both increase the solidity, and thus the ability to produce more thrust, but what drives optimal design? Longer chords mean more drag on an individual blade, but more blades mean more disruption of the airstream. Why and when choose one over the other?
Low blade count, low activity factor:

Low blade count, high activity factor:

High blade count, low activity factor:

High blade count, high activity factor:


texts: What type of batteries are used in airline planes?

texts:
In Embraer 145 and Boeing 777
I mean material, recharge cycle,  nominal current and voltages. From the comments I don't understand the difference if the plane is turboprop or turbofan.


texts: Are there any autopilots that are capable of landing a damaged aircraft better than any human?

texts:
How close are we to commercial aircraft with autopilots that can, as safely as theoretically possible, land an aircraft with damaged, missing, or otherwise inoperative control surfaces; or altered aerodynamics (e.g. ice on the wings), missing or misleading avionics (e.g., frozen pitot tubes), etc.?

Remember the Gimli Glider? An autopilot that could do that would be a good start.

And the computer in Space Shuttle Columbia made a valiant effort to keep the nose pointed in the right direction even as the aircraft was disintegrating.


texts: If sweep delays compressibility, why does 747 cruise slower than A380?

texts: B747 has a sweep angle of 37 deg and A380 has a sweep angle of 33 deg. If the main reason for sweep is to delay compressibility effects and increase operating Mach number, why does B747 cruise at a lower speed than A380?


texts: Has any Cessna Denali ever flown yet...?

texts:
With all the articles and hypes around the new Cessna Denali with its GE catalyst turbo-prop engine, I am wondering has any prototype of this plane made it into the air yet?

I understand that the performance figures can be partly calculated but am wondering how they can be so specific about its speed, range, load, and fuel consumption? Thank you.


texts: What is the difference between a positioning flight and a ferry flight?

texts: What's the difference (for the purpose) between positioning and ferry flight?


texts: How does the Mi-26 tilt its rotor like this?

texts: I watched this video on YouTube, which shows an Mi-26 taking off with its rotor tilted forward about 45 degrees. Is the video fake or is it real, and if it is real, how does the Mi-26 do such a thing?


texts: How should I handle a change of address for a Student Pilot License in the USA?

texts: I have moved to another place from current address with in same city, Do I have to change my address to the new one on my FAA Student Pilot License? If yes, how do I do it?


texts: Why have different pattern altitudes for different aircraft?

texts:
In the FAA AFD for Santa Rosa airport (KSTS), the pattern altitude is given as 1,000’ AGL for small aircraft, and 1,500’ AGL for large aircraft.

Why do these altitudes differ? Doesn’t it compromise having a uniform pattern altitude so aircraft can see each other?


texts: How much does it cost to learn to fly in the UK, and what restrictions are there?

texts:
Flying has been a dream for me since I was a little boy. My absolute dream career was to be a fighter pilot in the RAF. It's obviously a very hard career to get into, however I fell even before the first hurdle when I found out that I'm colour blind.

Finding out I was colour blind actually closed a lot of potentially enjoyable careers. Police, Armed Forces, Electrical all reject colour blind people.

I'd love to be able to fly, freely in a light aircraft - something like a glider or mosquito helicopter, but I just can't figure out where I need to start. Also, I'm not sure if it's financially viable.

Could someone give me a breakdown of costs and commitments needed?

Also, I'm assuming that being colour blind doesn't automatically mean I'm not able to fly?

Also, I'm in the UK


texts: Why do Computer Navigation Fixes still exist now that GPS waypoints can be used to define tracks?

texts: A CNF is a point that defines a navigation track for a GPS, but why is it used when you there are GPS waypoints that are created to define a track?


texts: Do the pilots have to recalculate the balance when 6 passengers show up last minute in a 737?

texts: Few years ago me and my mates forgot the checkin time and were late for flight. We were late for check-in counter closure (30 minutes before flight if i'm not wrong) but the staff allowed us to go on. We had no checked luggage. There were 6 of us so at least 400 additional kilograms to be carried. Do the pilot need to recalculate mass and balance or is it within the allowance?


texts: Distance of downwind leg from runway in glider landing pattern?

texts:
Is there guidance from the FAA or AGA on the distance of the runway from the downwind leg of a landing pattern for a glider?

For powered aircraft, the FAA recommends in its flying handbook (FAA-H-8083-3B) that the downwind leg be flown from 2500 to 5000 feet out from the runway, a pretty wide variance.


texts: Is it possible to 'retrofit' electric flight control actuators to replace existing hydraulic actuators on aircraft?

texts:
Read a bit about the potential cost savings of replacing existing hydraulic aileron actuators on large commercial aircraft such as the A350/380 with electrohydraulic/electromechanical actuators.

Airbus estimated that it achieved approximately 1,000 pounds of weight reduction on the A380 aircraft when a hydraulic aileron actuator is replaced by electrohydraulic or electromechanical actuator.
Source: http://mil-embedded.com/articles/motor-control-more-electric-aircraft/

Does anyone know if there are any ongoing efforts anywhere into replacing existing actuators with the 'more electric' EHAs/EMAs? Any insight is appreciated!


texts:
This aircraft was circling very low during the day, wondering if anyone could identify this plane.

this was spotted flying over the san francisco bay area.


texts: What rating can I add to a commercial certificate with the least time/effort?

texts:
I have an FAA commercial certificate with ASEL, AMEL, ASES, Glider and Instrument ratings (alongside specific type ratings). What additional certificate or rating will require the shortest amount of training to add?

It could be anything from sport pilot through ATP certificate, for any class: weight shift, multi engine seaplane, gyro-copter etc.


texts: How does the power requirement change when weight and speed change?

texts:
Suppose I have an airplane with a certain weight M, which uses a certain amount of power P, to fly at a certain speed V.

If I use the same airplane, but quadruple the weight (4xM) and double the speed (2xV), what is the resulting need in power?

I would like to understand the physics of this, for an ideal system. We can ignore how efficiencies change with velocities, etc.

Here is my reasoning: the airplane needs four times the lift to fly in the same mode, which will be provided since the speed has doubled. The only force the engine needs to overcome is the drag, which is four times higher, i.e. the required power is 4xP, four times higher.


texts: Is there any use for variable shape wings within aviation?

texts:
I am working on a variable shape airfoil which is originally intended for sailboats. However, I am wondering if there might be an application for such a design within aviation? The design I am working on can change thickness, camber, and twist quickly at the same time. The whole wing asymmetry can be mirrored within a second as well.

Is there an application for variable wing shape or geometry similar to this in aviation?


texts: What causes the inside glass of flight instruments to get hazy?

texts:
Sometimes on analog flight instruments (aka steam gauges) there is a haze or fogginess on the INSIDE of the glass that is NOT condensation. You can often find it on older aircraft with older instruments. But the instruments don't all develop the haze. I've spent some time trying to determine what this is and I found a few explanations, but only one of them addresses haze/fogginess inside the glass. This is one explanation I have found:

On instruments connected to pitot static system, it is the result of small air leaks which allows air to flow into the instrument and behind the glass, overtime it causes glass to get hazy on inside due to particulates in the vacuum air.

I find this to be credible but would like confirmation.

Additionally, I've noticed similar haziness/fogginess on non-pitot static instruments like Manifold Pressure, Tachometer, and others. So, there is likely another explanation for this.


texts: To what requirements / assumptions RSAs & EMAS designed?

texts:
I've several questions regarding runway safety area (RSA) and engineered materials arresting system (EMAS):

Is RSA/EMAS designed for impact loading at the point of touchdown and to absorb energy of the moving aircraft for deceleration?
Assuming that the landing gear is down: Can the load be assumed to be distributed equally through all wheels?
Are the brakes applied to assist deceleration over the EMAS?
What happens in case of belly landing and when there are burst tyres?
Is there any other loading case?
What are the max design loads and velocities?


texts: Do today's aircraft still have INS (inertial navigation system)?

texts: Do today's new aircraft like Boeing 787 still have INS (inertial navigation system)?


texts: How does Kalman filtering work in inertial navigation systems?

texts:
As far as I understood it correctly most INS-systems use a Kalman filter to compensate measurement errors.
I would like to know:

Does the Kalman filter compensate the errors from all the onboard sensors?
IIRC the Kalman filter is a tracker, that predicts future computation values. How is this useful here?
Is this used on IRS as well? Or only on older INS?

Thank you


texts: Why are 737-200 engines more susceptible to separation?

texts:
It seems the 737-200 had an issue with separation of engines from the wings. Considering that the engines are mounted completely under the wings, there should be more attaching points than a modern jet engine the question is why is this aircraft so prone to this sort of incident? Is it something to do with the airflow and the forces associated to it? Or is it purely a manufacturing defect?

Source:
https://www.flightglobal.com/news/articles/nationwide-737-engine-loss-inquiry-finds-fatigue-crack-in-mount-220017/

Snippet from the article:

  Fatigue failure of aft cone bolts has been attributed to a number of
  engine-separation incidents involving 737-200s – among them a US Air
  aircraft at Deptford in December 1987, a United Airlines jet at
  Chicago in January 1989, and a Delta Air Lines aircraft at Dallas in
  January 1992. All three lost their right-hand engines on take-off.


texts: What is the main reason of air-cooled radials producing much less HP/L compared to liquid cooled Vs?

texts: Is it because of the inherent limitations of cooling the cylinder walls, only 2 valves per cylinder, relative ease of scaling up instead of dialing up the boost, or some other reason?


texts: Why does Airbus suppress stall warnings in certain situations?

texts:
I was reading about Air France 447 and came across the line:

  The stall warnings stopped, as all airspeed indications were now considered invalid by the aircraft's computer due to the high angle of attack.

In short, due to pilot error, the aircraft (A330) reached a 40 degree angle of attack while under Alternative Law (due to icing conditions) and stalled at 52 kts. Further confusion came from the stall warning suppressing itself after some period of time.

  Roughly 20 seconds later, at 02:12 UTC, the pilot decreased the aircraft's pitch slightly, airspeed indications became valid and the stall warning sounded again and sounded intermittently for the remaining duration of the flight, but stopped when the pilot increased the aircraft's nose-up pitch.

It would seem, if the aircraft was stalled, and the computers knew the angle of attack was still far greater than normal, that it's most reasonable to assume the aircraft would still be in a stall even after other sensor data became unreliable. Also, if no airspeed sensors are reading valid data... seems it's most reasonable to assume the aircraft is in a stall... or on the ground (but wheel load sensors can corroborate when that's the case) - not just give up and assume everything is fine.

It seems to me, that perhaps this stall warning is at least partly at fault for this accident.

Why did Airbus design the stall warning system to suppress warnings in this situation?


texts: What are the effects of rotating airfoil sections to match wing's dihedral?

texts: While designing a wing, what are the advantages and disadvantages of rotating the airfoil sections to match a linear dihedral (airfoil sections always perpendicular to the dihedral line)? Does the lift force component tilts inwards and because of that, horizontal component  cancels out and there is a decrease in lift?


texts: I pilot the plane cessna in the simulator for a long time, and I always saw this VAC indication next to the Ammeter. What is VAC for and how to read it?


texts: What education is needed to become a civil pilot?

texts:
I'm from Croatia and I'm intersted in becoming a pilot, but however, I'm not going to the college deisgned for that (I'm studying IT, not aeronautics).

Nevertheless, I contacted Croatia Airlines and they told me that I needn't have an aeronautics college degree, but I do need these qualifications to apply for the First Officer (Co-pilot) position:

hold a valid CPL (A)
hold a valid multi-engine instrument rating (airplane) (ME-IR(A))
successfuly completed a Multi Crew Coordination (MCC) Course
hold a Category 1 Medical Certificate
hold a valid Associate Degree
hold at least English Proficiency Level 4
hold a certificate of passed ATPL (A) theoretical knowledge examinations according FCL.515
be minimum of 21 years of age
total flight time:

Ab-initio pilots: at least 250 hours total time, to include 100 hours as pilot-in-command of airplanes
Pilots with valid type rating: a minimum of 500 hours on respective type

So, I have a few questions.

Does someone know where I can get my licences for being an civil pilot in Croatia?
About theoretical knowledge (physics, mathematics):

Could I watch MIT OpenCourseware on that (and if I do, should I watch this or this?
I stumbled upon Flying Academy website (can't post the link because I'm new here) and it says "Sufficient level of knowledge of Mathematics and Physics".
What is sufficient and what would I have to learn?

I know I have a lot of questions, but I would really like to become a pilot one day and I believe I am self-disciplined enough to learn on my own. Can someone show me the way?


texts: Can MIL-PRF-5606H hydraulic fluid be used in place of MIL-PRF-5606?  My airplane is a 1966 Piper Cherokee 6.


texts: Can European (or more generally, non-US) airspace users airfile IFR flight plans?

texts:
In the US, there are two ways to airfile an IFR flight plan:

Call Flight Service on the radio via the nearest FSS RCO and ask them to file the plan
Ask the ATC entity you're talking to for a "pop up" IFR clearance

Is there any equivalent to either function in European (SES) airspace?  Or is Europe a continent where airfiling IFR flight plans is not possible?  (Bonus points if there's some sort of ICAO standard way of handling airfiling.)


texts: How can a pilot fly a distance of 594 NM connecting two VOR's?

texts:
I was researching worldwide airway designations when I stumbled upon this airway in Brazil: G678 with an MEA of 15,000 feet and a distance of 594 NM (nautical miles) between navaids.

It's drawn between the BSI and ATF VOR's. Mid-airway around S12°50.12' W52°4.38'.

Flying at 15,000' with BSI at elev ~3500', the line-of-sight is 166 NM. And as far as I know a high altitude VOR reaches out to 130 NM, maybe more, but certainly not 300 NM, right?

The "G" designation is for a non-area navigation route per ICAO annex 11. So it's a non-RNAV route. It's even colored black (vs. blue) on skyvector.

  A, B, G, R for routes which form part of the regional networks of ATS routes and are not area navigation routes.

So, how can it be flown?


texts: Why do fighter jets still have guns/cannons?

texts:
I noticed that the "new" F-35 still has a GAU-22/A cannon installed in it -- albeit with only  182 rounds (more with ammo pods).

Why do fighters still have cannons? The day of dogfighting is long over, now it's just fire some missiles and forget.  Even if they expended all their missiles, 182 cannon rounds is only 6 seconds of firing  (I think the GAU is rated to 1800 rpm).

The only reason (and I'm not sure if I should answer my own question) is that they need something to shoot warning shots over the bow of another airplane. But that seems an awful amount of weight for this rare occasion. And it'd mean loading tracer rounds.

Or is just a vestigial organ, like the sabres on the side of full dress military uniforms?


texts: Are there limitations in US legislation on a US citizen to own a MiG-15 in Europe?

texts:
If US citizen buys cold war era MiG-15 jet fighter aircraft, which:
- had been acquired from the museum (facility of the Ministry of Defense one of the European Union countries, member of NATO) by private person (contract document is available);
- is still located in that country;
- at least for time being the plane will stay located in that country even after the US citizen buys it from that private person;

Now, since that US citizen is also dual citizen of that country:
- Is there anything which he needs to do to be in compliance with US law?
- Is there anything which he should not do to be in compliance with US law?
- Or, since the plane will stay in that country (no import/export will take place), is everything basically governed by that country law only and he is good just to stay in compliance with the law of that country?

Does the same apply to any weapon/armament accessories present like cannons, gun camera, gun sight, ejection seat? E.g. cannons are now independently stored at the third party, licensed to handle military material. He would not get cannons to his possession until unless they are modified (deactivated) according to the law of that country.


texts:
General weather reporting for wind direction in Australian Standard the degrees in wind direction identifies where the wind is coming from.

Is it the same around the world?


texts: Is there a model to calculate fuel burn over the Atlantic ocean given an arbitrary aircraft identification?

texts: Is there any accurate model that can take flight data, plane identifications and compute the amount of fuel that the aircraft would burn flying a set route over the Atlantic ocean.


texts: How can you calculate the vertical speed of an helicopter during auto-rotation?

texts: How can I calculate velocity of a helicopter when it falls with autorotation when the engine fails, given all the parameters such as mass , height , wing size etc.


texts: How does flying a helicopter compare with flying a fixed wing plane?

texts:
There has been a lot of interest in the ease of flying a helicopter recently, and questions have arisen on how easy it is to control a helicopter in less than ideal circumstances such as low visibility.

What are the main difficulties in controlling a helicopter, compared to controlling a fixed wing aeroplane in similar circumstances?


texts: What avionics systems are interfaced with ACARS?

texts: I am a librarian looking for sources of information to help answer the following questions for one of our researchers: 1. what avionics systems are interfaced with ACARS and 2. how is the interaction between ACARS and these systems designed to occur in practice? As I am not very familiar with this subject, any information or pointers to information would be appreciated.


texts: Is prior clearance into Class B airspace revokable?

texts:
I was piloting outside of Class B airspace in an area well known for being difficult from which to contact ATC via radio because of mountainous terrain. When I did get cleared into Class B, I was only about a mile outside of Class B airspace. Immediately, another controller took over (different gender / same frequency), revoked the clearance, and said to stay clear of Class B and scolded me for only being one mile outside of Class B. (I complied with that request, never entering Class B – so there was no violation.)

Question: Can you legally be “uncleared” into Class B after receiving a clearance into Class B?
Could you speculate on what may have happened?


texts: Are there countries where commercial flying can be conducted with a Mexican DGAC private pilot license?

texts: I have a Mexican DGAC licence. Can I work in other countries, or do I need to get another licence? (for example an FAA one if I want to work in the US)


texts: Obtaining Captain's name on historical flights?

texts: Is it possible to find out the name of the Captain on a previous flight?


texts: What is the name of centre of mass speed of an aircraft?

texts:
I have a list of positions (X [NM], Y[NM], Z[NM]) of an aircraft. Every coordinate is given every 1 second.

I calculate the speed [knots] between two consecutive coordinates in the following way:

$S_{i+1}=\frac{\sqrt{(X_{i+1}-X_{i})^2 + (Y_{i+1}-Y_{i})^2 + (Z_{i+1}-Z_{i})^2}}{1s}3600\frac{s}{h}$

It's basically space over time.

Does this 3D speed have a specific name?


texts:
Other questions on this site say that go-arounds are roughly 1-3 per 1,000 landings. But in many of them, as described by passengers, the wheels don't actually touch the ground. Recently I had a touch-and-go (at Nuka Hiva, a small airstrip on a cliffy island in the Pacific) where our wheels most definitely touched the ground but we immediately accelerated and went around. The brief announcement said it was due to wind shear - we were safely on the ground on the second try so all's well that ends well.

I'm curious as to whether a true touch-and-go when a pilot is not practicing touch-and-go, on a commercial flight, is a significant rarity. By coincidence, this very same flight started with my first ever aborted takeoff, because a fuel overfill on one side had left us unbalanced; we returned to the gate and span one prop for 10-15 minutes then took off without incident. Am I in lottery-ticket territory?


texts: Can a commercial airliner sink to the bottom of the ocean?

texts: Is it possible that a commercial airliner could hit the ocean surface at such an angle that it made a deep dive intact, got filled with water, sank, and got stuck in mud at the floor of the ocean?


texts:
Source: Wolfgang Langewiesche - Stick and Rudder; An Explanation of the Art of Flying

I ran across a mushing glide in Wolfgang Langewiesche's - Stick and Rudder; An Explanation of the Art of Flying book and across this topic.

The author says: This gait is sometimes used by a skilled pilot, during an approach to a landing, to steepen the descent and at the same time make sure that the airplane will not pick up excess speed, as it would if the descent were steepened by diving.

I think that the same (or similar) effect can be achieved with forward slip, which, unlike mushing glide, points the nose down, thus giving a pilot a better view during approach while having a higher airspeed as a hedge from the stall. Besides better visibility and higher stall safety margin I assume (but with no scientific proof) that the descent angle with FS might actually be steeper, especially if a pilot slips at Vfe thus creating a large amount of drag.

That being said I wonder which flight condition/maneuver allows steeper approach and if there's any particular benefit of mushing glide to FS? What are your thoughts of this kind of approach?


texts: Who said "A little of all of us goes with every pilot we lose"?

texts:
The only attribution I’ve ever seen for the quotation below is “Anonymous FAA Inspector.”

  Whenever we talk about a pilot who has been killed in a flying accident, we should all keep one thing in mind. He called upon the sum of all his knowledge and made a judgment. He believed it so strongly that he knowingly bet his life on it. That his judgment was faulty was a tragedy, not stupidity. Every inspector, supervisor, and contemporary who ever spoke to him had an opportunity to influence his judgment, so a little of all of us goes with every pilot we lose.

Who originally said or wrote these words? What were the motivating circumstances?


texts:
I have tried to calculate all the losses associated with the serpentine intake to calculate the total pressure recovery.
I have considered the frictional losses, pressure loss due to bend, approach pressure loss and interaction loss. Now I should consider the adverse pressure gradient across the duct, so I am thinking of approaching it indirectly using the effects of adverse pressure gradient on the turbulent boundary layer.
I tried searching what would the effect would be of adverse pressure gradient on the turbulent boundary layer (i.e. change in turbulent boundary layer thickness due to adverse pressure gradient), but I am unable to find any promising results.
Hence, I would like to know if there is any formula or method to calculate the same mentioned above?


texts: What is the ATC protocol for hijackings?

texts:
If a commercial aircraft is successfully hijacked, by a competent pilot / pilots, and they make contact with ATC for regular requests (i.e. weather updates, flight path information or clearing air traffic), will ATC still aid the (new) pilots, or do they have some other procedure, like trying to persuade them to hand control back to the original pilots?

I'm just wondering if there is a formal procedure for such an event, as I'm guessing it's rather unlikely that they would contact ATC like that. But always possible, of course.


texts: What happens to Flight Testing Aircraft after Testing is over?

texts:
Are aircraft used for flight testing typically sold to Airline customers after their use for flight testing is over?

e.g. The aircraft shown in this SE Aviation Question:

Why are these windows on some airplanes red?

Sounds like a lot of money to waste so I expect they would be sold for some revenue but to what end use is the question.


texts: If they carry a lot of weight inside, what avoids them from falling down to the passenger's heads? What holds them? How are they mounted inside the cabin?