texts: Do commercial aeroplanes use ABS to brake?

texts: I have read that the wheel brakes on an aeroplane are by for the most efficient means of stopping it. I was wondering whether in low grip situations, such as in rain or snow, an ABS (Anti-lock Braking System) system is used to ensure the wheels do not lock. If not, why is this not necessary?


texts: What information on a specific flight can be retrieved?

texts:
I would like to know where and what to search in order to have information on a specific flight (i.e. scheduled departure time, real departure time, technical failures reported, etc.)

I'm guessing that this information can be found :
in the airplane's log
at the control tower (or the aeronautical uthorities)

Can you please tell me more about all this, especially the technical name of the different documents and the information contained within?


texts: I’m a new PPL and I would love to become a CFI in the next 2 years (or so). My objective would be to transfer what I know (and will have learned) to aspiring pilots. I’m older, though (just about to turn 60). Put it bluntly: am I too old? I know that we can’t talk about people being too old for almost anything these days, but I really would like to know if anyone (e.g. a flight school) would hire an instructor who not only brings rather thin experience (300-400 hrs by then) but combines it with rather ‘advanced age’. The benefit for a school would be that this would be my ‘forever-job’ (first, part-time and then full-time after I retire from my ‘day-job’ in a few years), not a stepping stone to an airline career. Please, feel free to tell me what you really think…


texts: I imagine checking ILS accuracy by measuring ILS signals at various points along the approach path is routine maintenance, although I don't know how it is done. How often must this kind of check be done to ensure the ILS is still accurate enough?


texts: Can military officers change occupation to become pilots?

texts:
From what I have read, the paths to become a fixed-wing pilot in the Air Force, Navy, and Marines, are to go to a military academy, enroll in ROTC in college, or go to an officer training school after earning a bachelors degree. In any case, a person will know if they are going to become a pilot before they become a part of the military.

For someone who is willing to become an officer in the military but is not offered a pilot slot when they join, is it possible for them to change their occupation before their contract has ended?


texts: What is the diameter of the nozzle of Trent 1000?

texts:
I am researching how much force is needed to divert the thrust of a Boeing 787 on its service ceiling of 13,100 meters and at a cruising speed of 913 km/h (data found on Wikipedia).

As I would like to fit a diverter to it, what is the diameter of the nozzle of Trent 1000 engine?


texts: Why are some US fighters' canopies tinted while others are not?

texts:
Ok, I'm sure we've all seen how some particular US fighters have tinted glass canopies (I'm not sure what you would refer to the glass as), while others do not. Looking at the currently in-service aircraft jet fighters, the newest kids on the block have very noticeable and iconic canopy tints. The F-22 Raptor has its iconic orange/yellowish tint that, depending on the viewing angle, can sometimes look golden. The F-35 Lightning II has been seen sporting several different colored tints such as a faded pink, blue, or yellow. The F-16 Falcon and the F-18 Hornet both have a traditional black-colored tint. However, the F-15 Eagle does not seem to sport any canopy tints. Same with the F-14 Tomcat, although it is no longer in-service and the majority of the F-14 fleet has been dismantled.
So, here is my question: Why is it that only some US fighters have a tint while others do not?
My first assumption is that it would be to protect the advanced avionics from being viewed, while other, more outdated aircraft do not need as much protection of their avionics and flight systems, which would explain the F-15. However, I may be wrong about all of this and the tint may purely be to prevent the pilots from being blinded by the sun.
I have yet to find a definitive answer to the whole tinting phenomenon anywhere on the web, so I would like to see if anyone here would perhaps have the answer I'm looking for.


texts: What are the ICAO fuel reserve requirements?

texts:
How much reserve fuel are private and commercial aircraft required to carry by ICAO rules?

I heard that it changed recently (about a year ago) and is a little complicated.  How is it calculated for a particular flight?


texts: What are the meanings of these terms related to instrument flight?

texts:
Please describe and define the following terms:

Homing
0 degree relative bearing
Tracking
Hold
Entry
Holding pattern

What are its uses and purposes?

Any one to suggest a thorough instrument book as well.


texts: What are the relative contributions of the body and wings to missile lift?

texts:
Slender bodies like arrow shafts, airliner fuselages, and submarine hulls are all capable of generating lift, albeit much less efficiently than a high aspect ratio wing. They also generate little drag, which is their main advantage. I would like to know how their lifting properties compare to that of a wing; to this end I would like to refer to a use case where the slender body makes up most of the airframe: guided missiles.

Consider a missile with a long slender body and short lifting surfaces, with a "conventional" air to air missile aspect ratio like that of the R-27 or AIM-120. The exact wing and control surface layout is not relevant, only the form factor. This means we should purposefully exclude munitions equipped with a moderate aspect ratio wing such as the TLAM or JSOW: I am interested in low aspect ratio BVR designs:

To avoid complications due to the engine or absence thereof, consider it flying in the coasting phase. The lift needed to stay aloft or even climb is then provided by a combination of the wings and the slender main body (where the guidance systems, warhead and sometimes engine are housed).

The question is, what is the proportion of lift coming from the wings compared to that of the fuselage?

NOTES:

A good answer should use a real or realistic design to base their calculations on.
I have purposefully left the choice of design open, so people can pick one they are familiar with or have data on. All that matters to me is that the general shape must be similar to that of modern AAMs.
Feel free to elaborate on how the lift proportion changes at different flight conditions (subsonic vs supersonic); it is quite clear that higher speeds lead to smaller wings.
I am aware that short range WVR missiles like the R-60, R-73 or AIM-9 are designed to reach their target before engine cutoff or shortly after; this has no bearing on the question.
This answer below presents a good extreme where most of the lift has to come from the body, because the only fins are too far away from the center of mass. In such cases, where the fins act as a stabilizer, their lifting force can still be calculated and compared to the total lift required, if we can assume the location of the CG.


texts: Can I apply for a Gold Seal any time, or only when I renew my CFI certificate?

texts: Basically my CFI certificate expires almost a year from now, but I have met the requirements for Gold Seal. Can I obtain my Gold Seal now, or do I have to wait until its time to renew my CFI?


texts: What is the folded size of a sectional map?

texts: Bending aluminum for a map box, and am curious as to the folded dimension of a sectional chart. My present resources use moving maps on EFIS and iPad, but I would like to carry standard paper charts.


texts:
A seaplane cannot use brakes to slow down, like a land-based aircraft. So how does one slow it down?

I am asking this in the context of landing, taxiing, aborted takeoff etc., as long as the plane is on the surface of water.

I imagine a few possibilities:

Land on a really long "strip" to ensure that water friction slows the aircraft down enough, then remember to not taxi too fast because you cannot slow down
If the plane has a variable pitch propeller, probably you can go to beta range to produce reverse thrust (what to do if the plane has a fixed pitch propeller?)
Steer left and right repeatedly (but wouldn't this cause stress on the airframe / chance to flip the plane?)


texts: Why are only some aircraft in this formation creating contrails?

texts:
The Republic Day celebrations at New Delhi, India had a series of flypasts by the Indian Air Force.

What struck me the most was that in a formation with a C-17 in middle and two Su-30MKI flanking it, there were contrails visible from the Su-30MKI but not from the C-17:

Both the C-17 and Su-30MKI have turbofan engines. For C-17, Pratt & Whitney F117-PW-100 and for Su-30MKI Lyulka AL-31.

As per 'How does contrail formation differ from turbofan to turbojet?', contrails depend on the bypass ratio of the turbofan engine:

  (...) higher bypass engines available today increase the contrail occurrence.

As per available sources, the F117 has a bypass ratio of 5.9:1 and the AL-31 has a bypass ratio of 0.59:1. So, the F117 has higher bypass compared to the AL-31 (or maybe I'm wrong).

What would be the reason that in the first two photographs, the C-17 engines do not form contrail whereas the Su-30MKI seem to?

One possibility is that, this difference is due to possible different power settings on the two aircraft engines for the same speed (considering the different intended role).

Another thing was that such contrails were not visible on any other fighter aircraft (e.g., Tejas/LCA). Or even another pair of Su-30MKI along with a AEW&CS aircraft:

Notes:

Sorry for the poor quality of photos due to the poor visibility in Delhi (winter fog/smog).
Some photos are here:

thequint.com
blogs.wsj.com
indiatimes.com


texts: Would adding a fairing to landing gear to spin the tires before landing yield enough benefits?

texts:
I was reading answers to this question: How long do airliner tires last? Can this be improved? and it seems to be reasonable to keep things simple and rethread tires instead of designing motors to spin them up.

However, what if one was to implement a simple aluminum housing like the one in the drawing below which will provide the following benefit.

When gear is deployed, due to friction of air only on the exposed part of tire thread, tire will spin up on it's own.

Has this ever been considered? Why would this kind of design work/not work for large airliners?

NOTE: the inside of the wheels are open for cooling purposes as well as various ducts can be incorporated for efficient cooling of the brakes.


texts: What is the function of the protruding outlet on the Trent XWB?

texts:
Original by Bernd Sieker from Germany (Trent XWB) [CC BY-SA 2.0], via Wikimedia Commons

Above is a photo of the Rolls-Royce Trent XWB highlighting the aft facing outlet in question.

In a video for the A350 you can see condensation coming out of it. Since I haven't noticed such protrusion on other jet engines before, it got me thinking, can it be a pressure relief outlet to allow higher fan RPM without choking the burner?

In other words, the engine would bite off more than it can burn to gain higher bypass thrust, and yet still be able to vent the extra air when not needed, at idle power for example.

Or is it just an oil drain for the accessory gearbox? That wouldn't explain the condensation though. Educated guesses are welcomed. I couldn't find anything on it.


texts: Could the toilet be used as an extra passenger seat?

texts:
In the US, if the toilet had a seat belt, would it be legal for an airline to board one more passenger than the number of normal passenger seats, requiring that whoever used the toilet last must remain there until the next person needs to use it?

Inspired by: "A new engine inlet reduces vibration and cabin noise, the lavatory receives a belted seat allowing a fifth passenger and the Garmin G3000 gets computed take-off distance and stability/angle of attack protection."  -- HondaJet Elite

Related Embraer Phenom 100


texts: Does the 300 hp IO550 conversion require an auxiliary tank on the Cessna 182?

texts: Does the 300 hp conversion with a continental IO 550 always require an auxiliary tank when used on a Cessna 182?  I see some of these conversions indicate an auxiliary tank is present under pilot seat but I would like to try to avoid this.


texts: Is it possible to land a plane only with the Garmin® Synthetic Vision?

texts:
A synthetic vision system shows the pilot the position of his plane in a 3D-modelled flight environment.

It's like a 3D TAWS. It also shows the position on the runway:

As I have seen, this feature works quite good. It's sometimes a bit off the centerline, but on the runway.

It is clearly stated that this is only to be used as feature to enhance the situational awareness. And I am also quite sure that this is not authorized as primary navigation source.

But imagine: You are flying in zero visibility. You have an emergency and must land. There is no ILS. (You have done no flight planning and the bad weather surprised you)

Would it theoretically be possible to land a plane only with this synthetic vision?
Is it accurate enough?
Would the plane at least come down in one part?


texts: Do Boeing and Airbus learn from each other?

texts:
Air France Flight 447 crashed into the Atlantic Ocean in June 2009. It was later revealed that the FO was unwittingly pulling the sidestick back, stalling the aircraft. The aircraft was an Airbus 330.

China Airlines Flight 006 almost crashed in February 1985 when the captain failed to step on the rudder after a sudden single engine failure at its cruising altitude and it got into a steep spiral. It recovered from the spiral descent thousands of feet above the Pacific Ocean but it experienced significant structural damages. The aircraft was a Boeing 747.

Some people say that the first accident could have been prevented if the sidesticks of the pilots had been inter-connected such that when one pilot moves his sidestick the other moves the same, just like the yoke system of Boeing aircraft. Also, some people say the second accident could have been prevented if the autopilot system had been programmed to correct excessive roll or pitch maneuvers caused by the pilot's control inputs or their absence.

But it looks like neither of the companies has adopted such suggestions, and that got me curious. Do they learn from each other? Do they correct their systems based on their competitor's accidents?


texts: Is separation provided in class F airspace?

texts:
According to the Wikipedia page on different airspace classes, separation is provided for IFR/SVFR to other IFR/SVFR in class F airspace. In ICAO Annex 11 from 2018 (p.36 in the pdf file), I can't find anything about separation being mentioned.

  Class F. IFR and VFR flights are permitted, all participating IFR flights receive an air traffic advisory service and all flights receive flight information service if requested.

I'd like to know if I have missed something and the Wikipedia page is right nevertheless?


texts: How can I use the "control hinge-moment coefficient due to tab" for sizing a trim tab on an elevator?

texts:
I calculated the control hinge-moment coefficient due to tab by using the dimensions of a tail and its elevator. However, the trim tab dimension parameters in the calculations were approximated values corresponding to similar aircrafts' tail geometries. Thus, what are the next steps to find the precise trim tab dimensions, and what is the role of the control hinge-moment coefficient due to tab in sizing a trim tab?

Notes:

the dimensions of the tail and elevator are precise and could not be changed
hinge-moment coefficient due to elevator is known


texts: What does ATC mean when they say "no longer a factor"?

texts: During radar vectors, the ATCo informed to the pilot, "no longer a factor." Please, can you clarify to me what this radio transmission means?


texts: How is a glider recovered and returned to an airport after landing in a field?

texts: If a glider has a safe normal landing in a cow pasture or other farm field and has no damage, how is it typically recovered to be returned to an airport for a future flight?  Are the wings designed for quick/easy removal and the wings and fuselage are just hand-carried to a long trailer waiting on a nearby road?  That's kind of how it's done (I believe) with balloon landings, but not sure what the process is for gliders.


texts: What notification am I required to give when starting an engine?

texts:
This question is related to a single-engined piston-powered airplane.

I was at a small airport. I noticed another plane parked behind mine. The pilot/owner was in the process of covering up his plane. I walked up to my plane, did some preflight checks, entered the cockpit, did my engine start checks, shouted as loudly as I could - PROP CLEAR - waited a few seconds and then started the engine. A few seconds later the other pilot walked up to me and was enraged that I had started the engine without notifying him. I told him that I shouted but he claims he didn't hear me.

What is the correct procedure/etiquette in this situation?
Was I supposed to walk up to him and notify him before starting the engine?


texts: How do aerodynamic loads explain the Spaceship2 accident?

texts:
From the NTSB's preliminary report, we read in the "Findings" section:

  Although the copilot made the required 0.8 Mach callout at the correct point in  the flight, he incorrectly unlocked the feather
  immediately afterward instead of waiting until SpaceShipTwo reached
  the required speed of 1.4 Mach.
  The unlocking of the feather during the transonic region resulted in uncommanded feather operation because the external aerodynamic
  loads on the feather flap  assembly were greater than the capability
  of the feather actuators to hold the assembly in the unfeathered
  position with the locks disengaged.

Taking into consideration that, as reported elsewhere:

  The vehicle's two tail wings are supposed to move when the spacecraft
  hits a certain speed, a maneuver known as "feathering." This
  repositioning helps to increase drag in order to slow the vehicle down
  for reentry.

From the article above, let's also take note of the visual depiction of such configuration change:

How is possible that this configuration change, meant to increase drag, needs a "preventing" (for lack of a better word) mechanism?
Since the repositioning helps to increase drag, how do the aerodynamic loads make the repositioning occour?
Wouldn't the (additional) drag on the tail section make it go back down again?


texts: How many planes did the Soviet Union lose to Stinger missiles during Afghanistan War?

texts:
I have read Wikipedia articles about the war in Afghanistan, and it is often said that the Stinger had a great impact on the air mobility of the Soviet military.

Beside the role of interdiction (A2AD) of the helicopters to go to the mountains and deliver assault and special troops, did the American-built missile destroy or damage a lot of airplanes and helicopters?

What sort of technologies and tactics did the Soviet Union deploy to avoid being shot down?


texts: Could a wing be designed to exploit both normal flying and ground effect?

texts:
Ground Effect planes' wings are stubby and the height over the ground or water is limited to wing span.
Could a wing be designed to exploit both normal flying and ground effect together to give the plane more clearance over waves without loosing all the benefits of the ground effect?


texts: Why are flight instructors in the US called CFIs?

texts: I live in EASA-land (Europe), here we call our flight instructors simply that, "FIs". That they hold an instructors certificate is simply implied. Why are flight instructors in FAA-land (US) called CFIs? Is there any historical reason why the "C" is always added to the abbreviation, e.g. in the past there was a difference between certified and non-certified FIs (if there ever was such a thing)?


texts: Why do large aircraft have their engines mostly on the wings, while smaller ones tend to have them in the tail or the tip?

texts:
Large passenger planes almost always have their engines hanging from the wings, Fighters usually have them in the rear, and small Cessnas have them on the nose.

What is the reason for these variations in design?


texts: When planes engage with guns, many of the shots are misses... what happens to the bullets? Do they kill people on the ground and damage facilities? Do we have any records of this happening?


texts: What are the circles/holes ahead of the wing of an MD-82?

texts:
In the picture below I noticed there are three circles or holes of some kind ahead of the wing, what are those?

(airliners.net)


texts: How can I determine whether or not an airport has an ATIS?

texts:
Where can I find the ATIS code and frequency for an airport through a VFR chart? For example, in the case of Frankfort airport (in the attached image), I can see the AWOS frequency but I am unable to locate the ATIS code and frequency.

Actually, Im try to fill a VFR navigation log at am unable to find the information to be filled in the Airport and ATIS advisory section. My departure airport is FKR.


texts: Has the wrong engine ever been mounted after maintenance?

texts: Keeping in mind that a plane can fly with different engine models (e.g. for test purposes), has an error ever happened during normal operations that led to the wrong engine being mounted? Is some kind of calibration or check necessary before flight to ensure that the engines are the correct ones?


texts: Is it possible for an airplane to produce thrust from compress air without using fuel?

texts: Is it possible for an airplane to fly as it compress the atmospheric air during flight?


texts: When was Kai Tak permanently closed to cargo service?

texts:
Kai Tak Airport in Hong Kong was closed to both passenger and cargo service early in the morning of 6 July 1998, with all flights moving to the brand-new airport at Chek Lap Kok.  However, shortly afterwards, Kai Tak was temporarily reactivated for cargo service (quoting Wikipedia; emphasis added):

  Government reports later revealed that Chek Lap Kok airport was not completely ready to be opened to the public despite trial runs held. Water supply and sewers were not installed completely. Telephones were installed, but the lines were not connected. The baggage system did not undergo extensive troubleshooting and passenger baggage as well as cargo, much of which was perishable, were lost. The government decided to temporarily reactivate Kai Tak's cargo terminal to minimise the damage caused by a software bug in the new airport's cargo handling system. During this period, the airport was given temporary ICAO code VHHX.

The article makes no mention of how long this arrangement lasted.

When did Kai Tak close as a cargo airport for the second and final time?


texts: Can jet fighter missiles descend or ascend?

texts:
I am wondering that if missiles fired from jet fighters can ascend or descend?

Are they going to aim only horizontally?


texts: If everybody jumps in an airliner, would the pilots notice?

texts:
I often have this thought when stretching my legs on a long haul flight: jump up and down in the cabin and see whether the pilots complain. Alone, it is unlikely my weight would have any noticeable impact on the plane's attitude, and I'd likely annoying some flight attendant or passenger around.

But let's say I manage to get all passengers on the flight to cooperate. Everybody jumps up pretty much the same instance (within reasonable human reaction time). Will the pilots notice its effect?


texts: Where is the lateral position of the aerodynamic center?

texts:
There is plenty of literature that describes how to find the aerodynamic centers (AC) longitudinal position.

But where would it be lateral?

My guess is somewhere near 1/3 out the wing from the fuselage, but I do not know..or would it maybe be close to the mean aerodynamic chord line?


texts: Is the sweep angle of an inverted wing zero degrees?

texts: Is the sweep angle of an inverted wing zero degrees, when the angle between the fuselage and the inverted delta wing is 90 degrees? Or is it different because the span of the wing isn't constant over the chord.


texts:
A simple question that I could not find an answer to:
When is a sailplane a sailplane (from a regulatory point of view), especially a powered one of the TMG (touring motor glider) variety?
EASA has some quite simple definitions, presumably modelled over the similar ones from ICAO, according to which:

‘Sailplane’ means a heavier-than-air aircraft that is supported in
flight by the dynamic reaction of the air against its fixed lifting
surfaces, the free flight of which does not depend on an engine.
‘Powered sailplane’ means an aircraft, equipped with one or more
engines having, with engine(s) inoperative, the characteristics of a
sailplane.
‘Touring motor glider’ means a specific class of powered sailplane
having an integrally mounted, non-retractable engine and a
non-retractable propeller. It shall be capable of taking off and
climbing under its own power according to its flight manual.

From this simple chain of definitions, it would seem that, for instance, a Cessna 152 could be classified as a TMG: It can take off and climb under its own power, and with the (non-retractable) engine inoperative it will do free flight sustained by its "fixed lifting surfaces", otherwise known as wings.
Since a Cessna 152 is not normally seen as a glider, I presume that there are more rules that need to be respected before a plane can be called a glider (or sailplane in EASA's classification).
I know that CS-22 contains the specifics, but is there a simple set of rules to determine if an aircraft belongs to the class of (powered) sailplanes as opposed to normal aeroplanes?


texts: Why does the MH370 ATC transcript never mention QNH? When is QNH given to aircraft?

texts:
Looking at the ATC transcript from MH370, I noticed that nowhere is the QNH communicated to the aircraft. That seemed odd to me... it seems that every time I talk to a tower or airways they tell me what the QNH is in their location.

So, is it normal for airliners to not be told what the QNH is before takeoff? Or in communications with DEPARTURE or RADAR?


texts: Why is using opposite rudder and aileron necessary in left turn for coordination?

texts:
This question goes against everything I've read or heard with the exception of a suggestion from my CFI in my last flight lesson, so I was hoping to get some clarification:

During a left turn into our crosswind leg my instructor informed me that I shouldn't be using so much left rudder, and in fact, might even need to use some right rudder to stay coordinated due to the left turning tendencies of the plane. I could somewhat understand given that I definitely noticed a tendency for the plane to roll more when turning left than right, but still I would think the antidote for that would just be less left rudder, not opposite rudder.

This does not make sense to me. In what situations would I need to do this? I was still able to perform my turns just fine with slight right rudder on my left turns, but I would like to understand this more.

FYI - I'm flying a Piper Cherokee 140 (PA-28-140)


texts:
In an aircraft like F-16, how do the pilot prevent going faster than Vne (velocity, not exceed)?

From the block 50 manual it seems to indicate Vne is 800KIAS/2.05M.

I believe even the earliest F-16s could go mach 2, so the newer with their much more powerful engine should easy exceed 2.05 mach.

Is there an automated system that reduce throttle when exceeding?


texts: Why do aircraft of the same model get progressively larger engines as they mature?

texts:
For example, the Cessna 172 started production with the Continental O-300 145hp engine but today sells with the IO-360. Granted that engine is more "modern" but 145hp with the O-300 still feels too little for such an airplane.
The Robinson R22 started with the O-320 and eventually jumped up to O-360.
Do the designers not feel the lack of power when test flying the aircraft? Are we getting fatter?


texts: How "full-motion" is a full-motion simulator?

texts:
How "full-motion" are simulators?  Do they just simulate the major motions of the airplane in response to the flight controls, or do they also simulate the minor forces of the flight, such as the vibration from the engines?

(Bonus question: if they simulate engine vibration, do they simulate the severe vibration from an engine that's just thrown a fan blade?)


texts: "right traffic pattern" vs. "right-hand traffic pattern"

texts:
Is it officially called "right traffic pattern" or "right hand traffic pattern"? I'm mostly interested in EASA terminology, but also FAA / other areas of the world.

Background: After I always said "right-hand traffic pattern" on frequency I got feedback from other pilots that I should leave out the word "-hand" to keep communication on frequency on a minimum - so I was now wondering, if there is any official terminology for that to be used. When looking in the Eurocontrol Phraseology Database, I only found "right hand pattern" for holding patterns.


texts: Why was the F-14 retired 15 years ago while the contemporary F-15 is still operational?

texts:
The F-14 and the F-15 were designed in almost the same years and each one was at the top of its own "compartment" (respectively, US Navy and US Air Force).
However, almost 15 years ago, the F-14 was retired in favor of the F/A-18, surely less powerful but probably more multi-role (while the F-14 was improved too for ground attack), while the F-15 was not superseded by the new F-22.
So, the F-14 was replaced by a project that already had 16 years on its shoulder in 2006 — the F/A-18 was a project of the 80's — but F-15 continues to be side-by-side with the F-22.
Why these complete different approaches to fleet renewal?


texts:
You have been given wind direction and speed, how would it be expressed?

Thanks


texts: How are compressor blades connected to the shaft in turbojet engines?

texts: The below figure is about rotor and stator blades of compressor . How these are connected to the compressor shaft in jet engines ?


texts: When the air-plane reaches to the altitude of about 12,000 m or so, the airplane's outside cover is very cold due to the air temperature or very hot due to the friction? Or it depends on different parts of the airplane?


texts: Do any airbridges move vertically to match arrival/departure halls?

texts:
One of the things that always baffles me is that airports almost always have the arrivals and departures sections on different levels, but that you exit the aircraft into the departures hall. In some airports this leads to long walks along labyrinthine corridors to customs.

Now it seems to me that one could easily raise and lower the other end of the bridge to match the hall being used. Domestic flights could exit directly onto the arrivals level, and international to the customs. Yes, this would increase the complexity of the bridges, but much less than the reduction in complexity of the rest of the airport layout while eliminating many escalators and elevators.

Does anyone know an airport that does something like this?


texts: Why does the Embraer E-Jet Family have doors of different sizes?

texts: I just noticed yesterday that the right and left forward doors of all E-Jet Family aircraft have different sizes (both in height and in width). What is the reason behind this design difference?


texts: Why are static ports external on a non pressurized aircraft?

texts:
Seems like the intruments in a non pressurized aircraft have access to the static pressure right where they are. It seems like external ports would be subject to more error being exposed, and lines that can be obstructed.

What benefit is having the external ports?


texts: Are we at peak speed efficiency for jet airliners at Mach 0.85?

texts:
The cruising speed of large jet airliners has not increased in the past four decades. The 747 cruised at Mach 0.85 and the new Dreamliner 787 also cruises at Mach 0.85 even though it was designed 40 years later (1969->2009) and uses advanced, composite materials and more powerful and efficient engines.  Meanwhile, faster airliner designs have been shelved, most notably the Sonic Cruiser (Mach 0.98).

This seems to indicate that as long as we value fuel efficiency over travel time, that we have reached peak speed efficiency at Mach 0.85 and that the only difference will be the comfort (or discomfort) of travel at that speed.

Are there fixed physical limitations at Mach 0.85 that make this the most efficient speed for jet airliners? Does this mean that even with advances in materials science and jet engine technology, we will not see significant transoceanic speed increases in the foreseeable future - so long as fuel efficiency is primary? Will airline travel forty years from now -- 2054 -- still be at Mach 0.85?


texts: What additional considerations do pilots have when deviating from the planned routing on flights dispatched under Method 2?

texts:
This article about Method 1 and Method 2 gives a brief explanation of Methods 1 and 2 in terms of dispatching flights under 14 CFR 121. Here's an excerpt.

FAR 121.191 requires that we dispatch our aircraft on a routing, weight and expected enroute temperature, that complies with a minimum terrain clearance requirement after an engine failure.
It also requires that we have a plan in place that allows a diversion to an alternate airport enroute,  following an engine failure and drift down, with a specific terrain clearance if we do not have the performance to continue to the destination.

My question about flights dispatched under Method 2 concerns route changes. In practice, I'm quite sure that pilots operating aircraft with a Method 2 dispatch release deviate from the planned route on the dispatch all the time. Reasons might include a shortcut request to air traffic control or deviations for weather. Weather deviations seem like the most relevant here because they can sometimes be quite significant.
What additional considerations do pilots have when accepting route changes on flights dispatched under Method 2? Couldn't changing the route render the Method 2 calculations irrelevant?


texts: How is a "conflict" between aircraft predicted and determined?

texts:
To answer my question about the prediction and determination of conflicts, we need a clear definition of the term. As far as I know is the term conflict often mistaken with the term loss of separation.

Let me start with the definition of conflict:

  Converging of aircraft in space and time which constitutes a predicted violation of a given set of separation minima. (emphasis mine)

Whereas the definition of a loss of separation is:

  A defined loss of separation between airborne aircraft occurs whenever specified separation minima in Controlled Airspace are breached. Minimum separation standards for airspace are specified by ATS authorities, based on ICAO standards. (emphasis mine)

To summarize the matter, a conflict between two aircraft occurs, not when there is a loss of separation, but when there is an impending loss of separation.

Seems pretty straightforward, right?

The challenge is that little word predicted. Who predicts the converging, when and by which measurements? When does a conflict occur in the eyes of an ATC-controller or a network manager? A related question is At what distance between two aircraft will the air traffic controller get an alarm?

I think this is a rather gray area, where probabilities come into play.


texts: For commercial flights, is there regulations imposing a minimum fuel reserve upon landing?

texts:
In aviation, weight is tightly linked to efficiency. The more fuel you take, the more weight you add and the less money you earn. On the other hand, you want to pack more to deal with unexpected headwinds or busy airports.
Following the 2008 economic crisis, banks were legally forced to increase their cash reserve to be able to withstand more uncertainty.
I understand that you get a priority landing spot if you're low on fuel but it only works when it's a marginal event. With fuel being one of the major cost of airlines, the pressure put by low cost operators, a will to reduce CO2 emissions, the advent of statistical analysis, it would be logical to see this reserve shrink with time until an accident happens; unless there is a legal limit no operator would dare going under?
I have no clue how well internationally-coordinated airlines regulation are (I would say not so good as the 737-max re-certification is done separately at least in the US, Europe and China), so any country specific value or international guideline is appreciated.


texts: Do any airports other than Mataveri restrict the number of airplanes that can fly within their sphere of influence at any one time?

texts:
Mataveri International Airport (SCIP), located on Rapa Nui (Easter Island; Isla de Pascua) in far southeastern Polynesia, somewhat famously, bans more than a single airplane from flying within the area of airspace that is closer to Mataveri than to any other airport (what we might call Mataveri’s “sphere of influence”) at any one time.

This is because:

Mataveri is the most isolated airport on Earth, such that a smaller airplane could easily find itself near the limits of its endurance if it were to be flown there and then forced to divert.
Mataveri has only one runway, meaning that, if said runway were blocked by a crashed or otherwise disabled aircraft, the airport would have to be closed until the runway could be cleared.

My question is: do any airports other than Mataveri restrict the number of airplanes that can be within their sphere of influence simultaneously?


texts: Why does an engine bleed system failure restrict operating elevation?

texts: Why are airplanes not permitted to operate to/from airports at over 9,200 ft if Engine Bleed Air Supply System #2 is inoperative?