texts: Why is being a commercial pilot stressful?

texts:
Being a commercial airline pilot regularly appears around the top of "most stressful jobs" lists.  I do not doubt that this is a stressful job, but as an outsider with no aviation experience whatsoever I do not understand why.  I am curious to hear a first-hand explanation.

I have always imagined flying long-haul to become very tedious and repetitive after a while.  The only significant source of stress I can see is time away from family/relationships (which admittedly I couldn't cope with, but it doesn't seem sufficient a reason to propel this to the front of most stressful professions).


texts: What kind of filters are being used to filter the bleed air?

texts: Bleed air is using by airplanes for various purposes including deicing and also to feed air conditioning units that maintain temperature inside cabin. What kind of filters does bleed air pass through before reaching the cabin?


texts: Why didn't the U-2 spyplane have any chaff?

texts:
The U-2 spyplane was shot down over Russia in 1960 and over Cuba in 1962, both times by a radar-tracking missile. Why wasn't it equipped with any chaff to throw off the missile?

Chaff is just a cloud of aluminum particles that return a big radar blur, masking the real craft so it can get away. The missile would home in on the chaff instead since it's a big juicy radar target. Chaff can be stored in very small cylinders near the tail of the plane, and the radar lock warning would let the pilot use it at the right time.

Chaff was invented in World War 2, giving plenty of time all the way to the sixties. So why wasn't this airplane equipped with chaff?


texts: How do I get certified to fly under FAA 333?

texts:
tl;dr: How do I go from non-airman to commercial UAS pilot under an FAA 333 exemption?

I understand that the rules are imminently changing, but waiting for the formal implementation of the NPRM could mean a very long wait before even getting started, and there is already a backlog of section 333 petitions.

Say I have a small (under 55 pounds) quadrotor aircraft, and I want to fly it for "civil operations" (commercial). As a non-airman, what do I need to do before I can operate the craft in this manner?

As near as I can determine, the process is something like this:

Obtain a pilot license
File a petition for part 333 exemption
Acquire either a SAC or Waiver/CoA

Do I really need to obtain a pilot license of some sort for real aircraft (either PPL, sport, or recreational) for this purpose, or can I legally operate the craft using some other short-cut? Is there a difference if I plan to fly a craft with a SAC rather than a craft which has none?


texts: Are there any footwear regulations for private pilots?

texts: Just wondering, as I'm working on my PPL during a hot summer, if it's legal (but probably more importantly, a good idea) to wear flip flops to fly a plane? I'm training in a 172, if that's an important factor.


texts: Why was the Sikorsky Firefly built but never flown?

texts:
Sikorsky Firefly is the electric helicopter that has been built but never flown. How do such histories happen?
If the design looked so unsafe that there was not enough courage of trying, why this was not discovered much earlier? If they changed they mind, lost the investor, why not to try at least once anyway if there is already a machine standing ready to power up? Is there any certification for even the first ever flight a prototype may fail to pass?
Stories like "a single prototype was tested but not more ordered" look much more logical (they did not like it after the tests).
What are the most usual reasons behind the "built, never flown" histories?


texts: I have my FAA Private Pilot License but I live in Chile, The thing is that I was asked by the father of a friend of mine to join him on a C182 flight in Chile (Chilean Aircraft). So, can I log  that time in my Log Book? Even though I did my training in a C172 and don’t have the High Performance endorsement?


texts: How can I triangulate a position using two DMEs?

texts: What is the formula for determining an aircraft's position (latitude, longitude) using barometric altitude and the ranges to two DMEs?


texts: Can a pilot rated in one category solo in another category without a current flight review?

texts:
Scenario:

A pilot is rated to fly gliders in the United States.
The pilot allows his glider flight review to lapse.
That pilot now decides he wants to get a type rating for the airplane category, single engine land.

Question:

Does the pilot have to be flight review current in order to solo in a powered airplane?
(Secondary question, as long as we are at it) Does the pilot have to be flight review current in order to take the FAA practical (check ride) in a powered airplane?

Note: I'm most interested in the answer under US FAA regulations, though the answer in other countries would be of interest as well.

I have spent some time looking over the FARs, specifically 14 CFR 61.56 and I cannot find anything conclusive either way.

I should mention that I suspect the answer to this question to be no, though I am not prepared to offer evidence to back this up.

I've already seen this related question asking whether a biennial flight review is valid for any airplane category, but I don't believe it's a duplicate because that only covers the situation where the pilot is rated in both catagories. This question refers to the situation where the pilot is rated in one category, but not the other.


texts: Does flutter disappear above the flutter speed?

texts: Okay, lets assume we have an airplane with some sort of superstrong wing, but otherwise conventional configuration. We accelerate it gradually. Eventually, it will reach flutter speed, at which the wingtips will flap up and down with ever increasing amplitude in a standing wave. But we don't stop there - we keep accelerating. 1.5x flutter speed. 2x flutter speed. 5x flutter speed. 10. What happens to the flutter? Does it disappear, then reappear again with more peaks and troughs of the "standing wave", at every multiple of the initial flutter speed? Or does it continue to get worse and worse?


texts: What is this intake bottom the wing of C-5 and why is it placed there?

texts: There are two intakes bottom the wings of C-5. What are those and why are they placed there?


texts: Why does indicated airspeed change with altitude?

texts: I know that if you fly at a low altitude and at a high altitude at the same TAS, your IAS will be lower at the high altitude than at the low altitude.   Why is this though?   Wouldn't the static vent account for the change in pressure?   I have heard it has to do with the change in density but why would this effect the system as it measures pressure not density?   Maybe because ram air pressure (measured by the pitot tube) is affected by density?


texts: Most turbofans nowadays use "variable stator vanes"; what are these, what is their purpose, and how does it affect a gas turbine's performance?


texts: For how long can a single-engine turboprop safely run the engine at idle?

texts: Can a single engine turboprop (such as a Piper Meridian or TBM) allow idling long enough to drop off a passenger or package without shutting down the engine? If so, would the prop be feathered but still spinning? Would idling with the prop not spinning (if possible) hurt the engine?


texts: What causes the horn-like noise during the start-up of some jet engines?

texts:
Here's the specific sound I'm talking about (it starts specifically 56 seconds into the video, as well as at 2:02 for the second engine):

I've only really heard that sound on low-bypass engines (F/A-18s, BAE Hawks, etc); they don't occur right at engine-start (so as far as I'm aware it's not just bleed air being blown into a turbine for spin-up); I was thinking that it's perhaps either fuel flow causing an increase in exhaust flow through a slowly-moving turbine, or that it might be the hydraulic pump (or something similar) connected to the engine accessory drive.


texts: Do aircraft have siren to warn public in case of a crash over land?

texts:
The recent crash of a Taiwan aircraft, got me thinking, do aircraft have built in siren, which can warn people on the ground of a possible crash to give them some headway.

If that is not practicable or feasible, then what solutions are feasible, or one should abandon the idea altogether and think of making planes safer in the first place?


texts: Does the SAS (stability augmentation system) actuators of f-14 use jet-pipe or flapper-nozzle technology?

texts: F-14 uses electrohydraulic servo actuators for its SAS. What type of hydraulic amplification is used in F-14? jet-pipe, flapper-nozzle or something else?


texts: What is the meaning of first flight and introduction in aircraft production?

texts:
They are info from wikipedia (here and here). I don't know many about the B-52 Stratofortress, but I'll take another case. The N-250 I remember its first flight which was performed with large scale, watched by Indonesian's former President and many other high rank officers. I remember the date, or at least the exact year. It was 1995.

Then my question is, if 10-Aug-1995 was its first flight which was performed with great fully, then what is the meaning of introduction (15 June 1997 in this case)?. If it was widely open to public when performing first flight, then why does an airplane needed to be introduced?


texts: How do airports determine when they should change their runway numbers?

texts:
Runway numbers in most of the world are based on the runway's orientation relative to magnetic north.  For example a runway with a magnetic heading of 135° to 144° will be numbered 14, and one with a magnetic heading of 145° to 154° will be numbered 15.
Runway numbers are occasionally changed due to changes in the Earth's magnetic field.

At my home field Runway 14/32 is oriented 145.7°/325.7°, per the FAA's airport diagram, and it has been this way for some time (I first recall noticing it over a year ago).
My understanding is that this runway should, at some point, be renumbered 15/33.

How does the FAA determine when to request that an airport change its runway numbers?
Is the decision to update the runway designation made by the FAA, or by the airport's management?


texts: How to interpret the term "standard" which is found in FAA's Obstacle Departure Procedures (ODP) and Standard Instrument Departure Procedures (SID)?

texts:
This might be obvious, but I find it difficult to interpret correctly the term "standard", when it refers to the takeoff phase of the flight.

Take, for example, the takeoff minimums for the La Guardia airport, page L16. For Runway 13, it states 400' ceiling height and 2¼ statute (I think) miles visibility but it does not mention any climb gradient. Is it implied that it follows the "standard" climb gradient of 200 feet per nautical mile? Next, it states that alternatively one can takeoff with the "standard" visibility rules, but only with a climb gradient of at least 280 FPNM until it reaches to 500 feet altitude. Which exactly are these standard visibility rules? The only source I remember finding states a requirement for 1 statute mile visibility for 1-2 engines aircrafts and 1/2 statute mile visibility for aircrafts with more than two engines, but no requirement for ceiling height.

Another example can be found by looking at this SID. Its takeoff minimums description states that for runway 4 "Standard" takeoff minimums apply. In addition, for runway 13, it states "400-2 or Standard with minimum climb of 280' per NM to 500." Does this mean that for "400 feet ceiling height - 2 statute miles visibility" the "standard" 200' per NM climb gradient applies, while for "standard" visibility a 280' per NM climb gradient is required?

I would be really grateful if someone could help me clarify the above rules.


texts: Are there big differences between Douglas Commercial 3 and Douglas Commercial 4?

texts:
I always thought of the DC-4 as a DC-3 with two added engines and somewhat improved hydros.

What are the actual differences between them?


texts: How are runway changes performed when radar vectoring is available?

texts:
When the time comes to make a runway change, let's say because wind has changed direction, how is this performed?

Aircraft might already be on finals, what does ATC do? Do they ask them if they want to continue with the approach or be vectored to another runway?
Aircraft might not be on finals but being vectored to the finals. Same question here.
Finally, there might be aircraft on the ground already taxied to the runway. Do they takeoff anyway or do they taxi to the new runway?


texts: Under what conditions can a flight continue beyond the point of in-flight re-planning?

texts:
I'm studying ICAO Annex 6, but I am confused a little bit about the paragraph below:

6-2.2.3.4.2(b)
A flight to be conducted in accordance with the instrument flight
rules shall not take off or continue beyond the point of in-flight
re-planning unless at the aerodrome of intended landing or at each
alternate aerodrome to be selected in compliance with 2.2.3.5, current
meteorological reports or a combination of current reports and
forecasts indicate that the meteorological conditions will be, at the
estimated time of use, at or above the aerodrome operating minima for
that operation.

Here I have simple question about following situations.

Can I continue flight at the point of in-flight re-planning if:
"destination airport WX > minima" & "alternate airport WX < minima"

Can I continue flight at the point of in-flight re-planning if:
"destination airport WX < minima" & "alternate airport WX > minima"


texts: How fuselage creates lifting force when plane flying on a side?

texts:
On a question "How plane able to fly on a side" people answer that it's because fuselage shape crate lifting force and plane should have enough thrust.
But that seems vague to me.
How fuselage creates lift ? Wing shaped that way that more air goes under it, so there more pressure below wing than above it. But fuselage is the same from both sides, so how it able to create lift after rotated on side ?


texts: If I've done multiple checkrides, when is my next flight review due?

texts:
Currently, I hold a Commercial Pilot Certificate, the question is when is my next flight review due?

Certification Dates are as follows:

Private Pilot - 02/05/2017
IRA - 11/10/2017
Commercial Pilot - 02/01/2018

It's supposed that a checkride counts as a Flight Review, so every checkride would add 24 calendar months to the initial?

Or it's just 24 calendar months after the last one?


texts: How many airport charts do airline pilots have in the cockpit?

texts:
I always wonder how many "backup" approach charts and airport diagrams airline pilots have in case the plane has to divert. I imagine a few possibilities:

There are no approach charts in the cockpit. The only ones the pilots have are those with the flight plan: the departure, destination and any alternates they picked along the route. If the plane must land somewhere else, the pilots will ask ATC to guide them in.
All of the fleet's destinations are available in the cockpit. If the plane diverts to any one of these airports, it is likely that there will be a ground crew to serve the passengers.
Every airport that can accommodate the size of the airplane is available, irrespective of whether it is a destination of one of the airline's routes.
Every airport within the operation area, no matter how big or small, is available.

I imagine with more airlines using Electronic Flight Bags, this would be a non-issue as one can easily load all available charts in the world onto the tablet, and updating them is trivial. Still I am interested in knowing what airlines typically do.


texts: Where is the weather data for the Garmin G1000 retrieved from?

texts: In a few videos I saw the possibility of looking for example at wind data. Now my question would be where does the G1000 gets the data from?


texts: Need communication example departing and arriving uncontrolled airport within class D

texts: I'm looking for a communication pattern to depart and arrive an uncontrolled airport within class D airspace VFR. One example can be F69 which is within KADS. This case looks even trickier because this airspace is right under class B. It seems to me it is possible to go under class B especially if going east. Would it be recommended considering how busy class B can be or it is actually a viable option to go from F69 into class D and then class B? It would be great if somebody could post links to videos. I'd like to know exactly what to tell and what to expect in reply for both cases departing and arriving.


texts: Does turbulent flow encourage/avert flow separation?

texts:
I know that turbulent flow has more energy than laminar flow and hence can sustain adverse pressure gradient for a longer period of time. It basically delays flows separation.

But referring to this source from aviationchief.com, turbulent flow encourages flow separation.
I'm not exactly sure whether statement is true so can anyone give me an explanation behind this concept

This is what I think - Since turbulent flow is known for having skin friction drag, it slows down air after the suction peak. This slow down of air (due to pressure rise and skin friction caused due to turbulent flow) is gonna cause flow separation.


texts: What could cause an irregular climbing pattern on takeoff?

texts:
Yesterday (Dec 21, 2015), I was on board Ryanair flight FR4966 from London Stansted (STN) to Lamezia Terme (SUF). The aircraft was a Boeing 737-800, registration EI-EFW.

On takeoff, the climbing pattern didn’t seem very regular to me. It was clear that the engines were first running at full power, but then decreased their thrust and our altitude seemed not to increase as it would regularly do. I was certain we were about to return to STN due to some kind of malfunctioning. However, we reached our destination flawlessly.

Later, I checked the climbing pattern, and my impression was confirmed. You can see below that the climbing pattern was initially steep, but at an altitude of approximately 5,700 feet, the aircraft stopped climbing and proceeded at the same altitude for about 5 minutes.

My question: what caused this steady situation? Did the aircraft undergo a malfunctioning that the cabin crew was able to cope with? Or was it just due to the fact that we were overflying London — a congested airspace — and that was our assigned altitude?


texts: Why are follow-me cars used in Gran Canaria Airport in good visibility for incoming aircraft?

texts:
I've been at GCLP (Las Palmas de Gran Canaria, Spain) a few weeks ago.

I've observed that all incoming traffic was guided by a Follow Me while outgoing traffic went without one.

I was curious about that and looked for an airport chart to find more about it. The latest I've found is a Jeppesen chart from DEC 2004... so a bit outdated.

There it states in the LVP (Low Visibility Procedures) section only, that pilots have to wait at apron entry for the Follow Me while outgoing traffic should avoid requesting clearance in such a situation.

There is no notice, about what applies when LVP is not active.

What could be the reason for doing this even in good weather situations (visibility was at least 10km, if not even more)?


texts: How to convert an EASA ATPL(H) IR to ATPL(A)?

texts: If you are holding an EASA ATPL(H) IR, how can you convert it into ATPL(A) and would you be able to credit your heli hours? As I've 400 hours and it would get longer to build hours with ATPL.


texts: Which airliners have carried the most passengers?

texts:
I'm fairly sure that the Boeing 737 series will be in first place, with the Airbus A320 family coming second and perhaps the 727 third.

However, perhaps there are some estimates of actual figures that would provide more information.

See also Which individual aircraft has carried the most passengers in its lifetime? for a related question about passengers carried by an aircraft series.


texts: When are aircraft required to dump fuel for emergency landings?

texts:
I've heard that in a lot of instances a jet that is making an emergency landing is required to dump excess fuel.  In a lot of instances this would make a lot of sense.  For example, if the gear cannot be lowered and the plane must land on its belly.   The last thing you want is a hundred tons of jet fuel involved.

But, I have to assume there are also emergencies where a plane isn't required to dump its fuel.  I just am not sure what they would be?

So, my question is: When are aircraft required to dump fuel before landing (or, at very least, when is it advisable to dump fuel before landing).

Bonus points:

How much fuel does an aircraft retain after an emergency dump? I'm
assuming they don't dump it all or they would have no fuel to
maneuver with.
Examples would be great.


texts: What are the durations of strokes and events in a 4-stroke engine?

texts: I'm learning about engines, and I understand the basics of how a 4-stroke engine works, but I've seen lots of true or false questions such as "The power stroke is shorter than the intake stroke" or "The power stroke is longer than the power event". What's the difference between strokes and events, and where can I see more about how long each one takes?


texts: What is the meaning of the percentage used to describe the thinness of this glider's airfoil?

texts:
In a glider review for the Schempp-Hirth Discus, I encountered the following paragraph:

  The Discus 2 airfoil is thin (about 14.5 percent), incorporating studies by K.H. Horstmann and Dr. Wuerz (wing) and Luc Boermans (tail).

After researching this a bit, I've been unable to find an explanation for what "14.5 percent" was referring to.

I thought perhaps that it is the ratio (14.5/100) of the thickness of the wing to the width of the wing, but that is really just an educated guess.

The Wikipedia page on airfoils has a section entitled Thin airfoil theory, with two bullets which also might qualify:

  (1) on a symmetric airfoil, the center of pressure and aerodynamic center lies exactly one quarter of the chord behind the leading edge
  (2) on a cambered airfoil, the aerodynamic center lies exactly one quarter of the chord behind the leading edge

Is this "one quarter" the ratio that is mentioned in the article?

I did see this post, but had trouble seeing how the 90% and 99% numbers mentioned in the answer are related.


texts: Can a jet stream make a subsonic plane fly at a supersonic speed relative to the ground?

texts: If a plane flies with a jet stream, its speed relative to the ground is the sum of the speed of the jet stream and the speed of the plane relative to the air in the jet stream. If the speeds that are added together are subsonic, can the resulting speed of the plane relative to the ground become supersonic? If it can, does the plane create a sonic boom on the ground?


texts: What is minimal altitude that aircraft (rocket?) can fly above any country without any permission? I mean, at what altitude ends country's airspace?


texts: Can APU start in-flight using RAT or battery power?

texts: Is it possible for a passenger jet to start its APU using power from the RAT? If so, are there plausible benefits to doing so (like supplying hydraulic pressure to the wheel brakes)? Do modern passenger jets frequently (ever?) operate with the APU not running?


texts: Approximately what percentage of aircraft are equipped with RNAV?

texts:
I was hoping someone could provide me with an estimate of what percentage of aircraft are equipped for RNAV (Area Navigation). I'm more interested in commercial aircraft, but business and general aviation would be nice to know too.

This is for my own curiosity, so speculation is perfectly fine.


texts: When were checkerboard fiducial markers first used in aircraft development?

texts:
It's common to put checkerboard fiducial markers on aircraft to help analyze rates and orientations from photographs and film.

When was this practice first used on aircraft?

Flight test versions of the German V-2 rocket were painted in a checkerboard scheme, presumably for fiducial-marking purposes (or just high visibility); was this already established practice at the time of the first V-2 test flights in 1942?


texts: What is the difference between Level Change and ALT INTV during VNAV descent?

texts:
I'm confused between the two. During descent for 737 PMDG, I usually start a descent via ALT INTV, but sometimes the plane doesn't response to ALT INTV but responds to LVL Change instead.
I need help to understand the difference.


texts: What are the most maintenance-intensive parts of a helicopter?

texts:
Which components of a helicopter are the "driving" ones that require most regular attention and down-time, and how often do they last between inspection or overhaul? I don't have a specific model in mind, but something along the lines of a 4-passenger light transport heli

Along with this, are there developments that might increase these intervals, and how much is defined by the manufacturer vs regulatory bodies (FAA/CAA/EASA etc.)?


texts: Can an F-16 land on an aircraft carrier, at all?

texts:
Looking at the F-16 again, I noticed the tailhook which it seems to have. I know the F-16 is not designed to land on any aircraft carrier, however, if it was between ditching in the ocean and attempting to land on a carrier. During wartime or any emergency; if the F-16 found itself over an ocean and needed to land, and there was a friendly carrier nearby. Could it be done?

For this we assume an unmodified F-16, any of the F-16 variants are candidates for this thought experiment. However, I assume the lighter F-16A (I assume they all have the hook, even the early block A variants?) is better, since it has less mass which needs to come to a full stop?

I understand that this will probably be speculation at best, I'm just curious. Forgive me. If someone happens to know the figures of maximum load on the F-16 tail hook versus what would roughly be required, that would be awesome. However, I'm also taking just educated guesses.

My own layman efforts towards an answer, limited to mostly just identifying some obvious issues:

Is the F-16 tail hook even compatible with the arrest system an aircraft carrier uses? Perhaps it wouldn't catch the arrestor cable at all.

If it does catch it, perhaps it is not designed for that kind of abuse, and would tear straight off the airframe if this was attempted.

For carrier landings, the aircraft will typically from what I understand not flare and make hard landings which really beats the undercarriage. I'm not so concerned with the undercarriage breaking, it would be better to recover an F-16 with broken undercarriage than losing it to the ocean.

However, if the undercarriage does break, it might prevent the hook from catching the cable at the correct angle. Even if it does grab the cable, perhaps the aircraft with broken undercarriage would risk sliding off the side of the deck.

From what I understand, there are no barriers on modern Nimitz carriers any longer. Hence they will not be considered as an option. Perhaps a barrier could catch an F-16 but I'm more curious about the properties of the hook, undercarriage, and other issues with landing on a carrier.

I know landing on a carrier is hard, so what is it that makes it so hard for an F-16?


texts:
This question is bordering between aviation and biology. I am posting it here, since it is really about aerodynamics.

At first, one would think, that birds should be aerodynamically stable to save themselves the effort of maintaining stable flight.
However, even if humans had rigid joints they are in an unstable configuration other than four-legged animals. Thus, stability does not seem to be a must for biology, at least in certain aspects.

So, are birds aerodynamically stable? Are all of them, or are some species which are and some which aren't?


texts: What would have happened when the Concorde's low-pressure emergency system brought it lower mid-flight?

texts: My understanding is that the Concorde was equipped with a system that automatically lowered the aircraft to a safe altitude if cabin pressure was lost. I know such emergency never occurred in its history but did the Concorde have the range to make it to the closest airport if say this happened in the middle of the Atlantic. With a range figure of approximately $6500$ km at Mach $2.0$ and $50000$+ feet cruise, it is not clear that this bird would make it to land in such an emergency given it was terribly inefficient at low speeds and altitudes. What happen if this emergency had ever happened?


texts: Does the velocity of air in an engine increase in the compressor section or turbine section?

texts: I think it increases in the turbine section because the pressure and temperature decrease so the velocity increases but I'm not sure.


texts: Does the definition of visibility take object size into account?

texts:
Overall, visibility is the distance at which objects may be discerned.

Does this definition take into account the size of the objects? Obviously large objects can be seen from farther away than small ones.


texts: Can heat from the engine inlet be used to produce thrust?

texts:
As the engine inlet temperature increases, Is more heat energy provided by air?
if yes then can we utilize that heat energy to produce more thrust?


texts: What was the motivation for revoking the licence to the pilots of Northwest flight 188?

texts:
This video describes Northwest flight 188, where two pilots overshot their destination by 150 miles, without contacting ATC for an hour. They cited 'cockpit distractions' as the reason and subsequently, both had their licenses permanently revoked.

What exactly was the license removal be for? Overshooting the runway? Not contacting ATC for an hour? And what are the quantitative rules on this, i.e. how long would you have to not contact ATC for or how many miles off course would you have to go to get your license revoked liked these two did (in a commercial setting)?


texts: Is there any U.S. / FAA regulation that could apply for aviation software?

texts:
I want to build some software applications applied to the aviation industry and would want to know if any U.S. / FAA regulation could apply in the design of them.

I know there are some regulations when a software holds information related with finance, health or kids.


texts: How is the battery power on the Airbus A340's electric system switched?

texts:
On the electric panel of the Airbus A340 there are three battery buttons (BAT 1, BAT 2 and APU BAT, indicated by (3) and (4) in the diagram) controlling battery charge limiters. When the aircraft is on the ground, below 50kts and batteries are the only power sources (as FCOM states) batteries 1 and 2 should be connected to the DC-Battery bus (DC_BAT_BUS) and the DC-Essential bus (DC_ESS_BUS).

source: Airbus A340 FCOM 1.24.20 P1 REV08

Should both of battery buttons 1 and 2 be pressed to Auto mode to have these connections? Or it is possible to connect battery 1 separately from 2 to DC_BAT_BUS? Seems that both buttons should be pressed to have such connection to DC_ESS_BUS, but for DC_BAT_BUS it is not so obvious.


texts: How does keeping the parking brake applied when brake temperatures are high contribute to the dragging brake phenomenon?

texts:
While going through a presentation on the Airbus WIN application with regard to cost saving practises. It was told with regard to brake life. If the parking brake was applied when the brake temperatures were still high that it can contribute to the dragging brake phenomenon.

Could someone help explain how does this happen ?


texts: Why does the cabin pressurisation switch have a manual mode?

texts:
Reading about Helios Flight 552 it is clear that the pressurization switch on a B737 has two modes: AUTOMATIC and MANUAL

Since it appears that one of the causes of the accident was an incorrect setting of the switch to MANUAL and due to hypoxia the first officer didn't spot the problem, why is it that a MANUAL setting is offered if it can lead to such disasters?

What is the use of the MANUAL position of the switch if the setting has to be set to AUTO for the flight?


texts: What is the descent rate in emergency situations?

texts:
I fly a plane at 40000 feet. There is a sudden depressurization; what is the maximum vertical speed I can keep to come back at a proper altitude?
Is this speed different for different emergency situations? (Engine stopping/fire/general emergency).

Are there any numerical maximum values in different scenarios for, for example, a A320 or a B737?


texts: Where can I find the number of commercial jets that a country or airline purchases annually?

texts: Is there any authoritative source from where we can find out the number of commercial jets that a country or airline purchases annually?


texts: How do non-US pilots get the hours necessary for an ATP?

texts:
I'm wondering about the possible lack of real-world flying experience by pilots in non-US carriers

In the US, aspiring airline pilots can work at a variety of jobs, like instructing, towing banners, crop dusting, etc, or part 135, to build time towards the 1250 hours now necessary for a restricted ATP to act as Second In Command (SIC) in carrier operations.

How do non-US pilots who don't have a military aviation background build the hours necessary to obtain an air carrier license in their own country? Are they all ex-military? Do they only need an ICAO-compliant commercial license and not an Air Transport Pilot License (ATPL)? Do we have 250- or 500-hour commercial pilots flying SIC into JFK?  Do these pilots have experience flying non-pushbutton aircraft?

Not sure if this is credible, but, as an example, there are fewer than 30 non-air carrier turboprops (Caravans, twin Cessnas, twin Beeches, and a lone Cheyenne) registered in Malaysia, and 10 are registered to the air force. The same site says Jordan has 7, 6 of them in the air force. Where are the national air carrier pilots getting their twin time? SIC in domestic carrier ATRs and Dash-8s?


texts: Can pilots use PAN PAN Medical, even if they were not on MedEvac mission?

texts:
If there is a medical emergency on board, on a passenger or crew member, will the crew be cleared to use PAN PAN/MAYDAY MEDICAL on their R/T?

Is there any DOC in which regulates these phraseology?


texts: What are the effects of communicating on VHF/UHF on a RMI's ADF needle?

texts:
Say you've properly tuned an ADF station in COMP mode so that the BRG needle on your RMI is pointing towards your station. Then you tune the same ADF frequency on your V/UHF radio. Does anything happen to your needle at this point? How about when you transmit on that frequency?

Edit: Meant RMI


texts: How do preceding aircraft affect the ILS signals?

texts:
(airliners.net) Planes on approach in sequence to London Heathrow.

When LVP is in effect, the ILS area is protected.

I'm wondering, when there is a queue to a runway, how does the long queue affect the signals for those behind?

I'm guessing it does somehow, and the answer may shed some light on the new Enhanced ILS.


texts: Do pilots pilots keep track of their groundspeed, by head?

texts:
For VFR nav. flights, do pilots have to keep track of their groundspeed, by head (done so by considering wind speed, wind direction, crosswind, tailwind etc.)?

And the purpose of this, is to check that you are on par with your pre-planned flying time?


texts: Why are heading in PFD and map off by exactly 10 degrees?

texts:
I was flying on my X-plane 11 flight simulator today and noticed something quite unsettling.

This was a VFR flight between KIAD and KDCA. I pulled up my map for reference and noticed I was flying orthogonal to the map's north direction, even though I was flying a heading of 100.

The image shows the map and the PFD for your reference.

What is going on? Did I mess with some heading calibration setup? 100 degrees and 90 degrees are perfectly 10 degrees off, so I don't think this has to do with magnetic north issues.

P.S. Strangely, I got to my destination simply following the headings from ATC.


texts: What are the reasons for an installed engine to produce less thrust than an uninstalled engine?

texts: Is this only due to the various flight conditions encoutered during operation, such as side winds and turbulence, or are there other reasons? Also, is interference between fuselage and power plant involved?


texts: What is (theoretically) the most efficient shape for an aircraft, assuming you don't have to carry any cargo?

texts:
Assuming that you don't need to have any large piece on the underside dedicated to storage area/people (as all planes do) and you don't care about stability, what is the most energy efficient form for an aircraft in terms of energy required to maintain altitude? I would guess that it is the flying wing.

What it should do:

Use computer control if needed to reduce power requirements

All other requirements take second place; efficiency is the dominant goal.


texts: What is the difference between a turbofan and a turboprop engine?

texts: I'm not an aircraft expert and I just realized that there are two different terms - turbofan and turboprop. I always had them combined in my head as a term for a large jet engine (like you would see on a 747). Apparently this is not the case though. So what is the difference between them? Are there other types of "turbo" engines?


texts: Is there a standard format for pre-departure clearances?

texts:
I am curious to know, from current airline pilots, if the formatting - and therefore reliability and ease of use - of pre-departure clearances (PDC's) has improved since they were first introduced?

Back then we would see differing formats, incorrect flight numbers and routings, and the like.  ATC would send them to the company and then the company would give them to the flight crew together with other relevant documents.

I'm sure that the process has greatly improved since those days, but I'd like to know if PDCs have now been standardized?


texts: How many labels are defined in ARINC 429 for calibrated altitude?


texts: What is the behavior of false glideslope signals?

texts: I know that an ILS transmits not only the correct glideslope but also signals that can be interpreted as a false glide path. But I'm not familiar with the details of these erroneous indications. What causes "side lobe" or "mirror" false glideslopes? How many are there, where are they located, and what sensing do they cause in the aircraft? What is the typical behavior of a glideslope signal outside its usable range, or is it completely unpredictable?


texts: Do special procedures exist to limit pilot workload during pilot incapacitation?

texts:
Although pilot incapacitation is rare, the website avherald.com lists several occurrances of flight crew incapacitation, alone two events reported yesterday.

FAA AC 25.1523-1 requires all aircraft to be capable of operation
by one pilot only from either seat, so just one pilot can safely fly the aircraft - albeit under increased workload.
In case of flight crew incapacitation, do airlines (or regulatory bodies?) have dedicated Standard Operating Procedures (SOPs) for the remaining pilot? Obviously, the pilot would declare PAN/Mayday and assess whether it is safer to land asap or continue. Or are there no special procedures because it happens so rarely?

Are there any procedures to limit pilot workload in these instances, such as shortened procedures, ask a cabin crew member for assistance such as reading checklists, any support from the ground / airline operation center...? The remaining pilot must execute all tasks of Pilot Flying and Pilot Monitoring, which means heavy workload during final approach.


texts: Why do turbofans go faster than turboprops?

texts: Can someone explain why turboprops are less effective in terms of thrust than turbofans? But at the same time, why turboprops burn less fuel? For example, the Bombardier Q400/De Havilland Dash 8 has a fuel burn of 2.79L/seat/100km, whilst the 737 MAX 8 with the same number of engines burns 2.93L/seat/100km, but the Bombardier has a max. cruising speed of 360 knots and the Boeing plane can go up to 526-527 knots, even though it's heavier.


texts: How to find total climbing time based on Rate of Climb?

texts:
I am unsure on how to solve this problem. The only clue i have is to integrate ROC to find time.

A jet aircraft has the capacity to fly at an absolute altitude ceiling of 11000 m,
and a rate of climb (ROC) at sea level of 20.87 m/s. Calculate the time to climb
from sea level to 8000 m. Assume a linear variation of the rate of climb with
altitude during the whole maneuver.


texts: Can you fly the plane manually without disengaging autopilot?

texts:
Let's say you are engaged a Boeing 777 with autopilot on and you bank or pitch. Will the plane respond?.
If so. will the plane try to return to its parameters once you quit handling the controls?.
Same question for any Airbus.

I read that in the case of a TCAS RA you need to disengage the autopilot and fly manually. But let's suppose your TCAS tells you to Climb and you pull your yoke without disengaging the AP. What would happen on a Boeing or on an Airbus?


texts: Does a Mach 1 plane hear a sonic boom from a Mach 3 plane overtaking him?

texts:
Let's say Bob is flying at Mach 1 and then John, in another aircraft, overtakes him at Mach 3. They are flying parallel to each other, say 500 meters apart. And there is no wind. Their relative speed is Mach 2 of course. Does Bob hear a sonic boom from John, and why or why not?

Please explain it sufficiently enough so that I can apply it to other situations. For example, would it still work if their speeds were more like Mach 1 and Mach 1.25?


texts:
What was the mass of a fully fueled Hindenburg (discounting any cargo other than fuel/gaz) ?

I do mean to exclude any lift provided by buoyancy.


texts:
Reading this article (on the Boeing 737 MAX saga; irrelevant), I found the following excerpt:

  Boeing ultimately accepted Davies recommendation and, we understand,
  halted production of the 707 for 10-11 months, whilst a new fin was
  designed and installed.  All existing 707s were then retrospectively
  modified.  A ventral fin was also installed on some variants to
  prevent ‘fully stalled take-offs’ which the Comet was also susceptible
  to.

I tried to search, but I found nothing on "fully stalled take-offs", whether about the Comet or any other aircraft.

So, what is a "fully-stalled take-off"? Are some aerodynamic designs (or aircraft models) more susceptible to it?


texts: How are Virgin Galactic's SpaceShipTwo's windows so large?

texts:
From Virgin Galactic on SpaceShipTwo:

  Windows in the passenger compartment will be 13 inches (33 centimeters) wide by 17 inches (43 centimeters) tall.

IMO that's enormous for an airplane, especially for a spaceplane! But, wouldn't such large windows cause problems? The Concorde had particularly small windows (passengers say that it's almost passport book sized) to maintain the integrity of the airframe and cabin pressure if a window happened to crack at 60,000 feet AMSL.

But wouldn't such a large window cracking at 110 km AMSL on SpaceShipTwo definitely cause cabin pressure to equalize to atmospheric pressure in seconds? What redundancy does SS2 have to prevent catastrophe in such an event?


texts: How to correct for crosswind in VOR holding pattern without wind information?

texts: I've heard many articles about crosswind correction in VOR holding pattern. They mainly tell the outbound leg=correction times three things for slow speed aircraft. I notice all of them require wind information in holding pattern. What if somehow under some circumstances the pilot doesn't have the wind information whatsoever in holding pattern? Like the wind may change unexpectedly. Is there any method to maintain precise 4 minutes holding pattern in such condition?


texts: What are the differences between the different types of TCAS?

texts: In discussions about TCAS I've overheard mentioning different levels such as "TCAS 1" or "TCAS 3." What are the different types of TCAS and how are they different?


texts: Can noise from the passenger cabin be picked up by the cockpit voice recorder?

texts: How sensitive is the cockpit voice recorder?  Can it pick up sounds from the passenger cabin?


texts: Why burn fuel at departure airport instead of flying to destination before emergency landing due to deflated tire?

texts:
A Southwest airliner recently had an issue where a "deflated tire indicator" showed on one of the landing gear tires after takeoff from Oakland, CA. They circled nearby for 4 hours while burning off fuel before landing back at Oakland.

In a circumstance like that, where there's no flight control or aerodynamic problem (i.e. landing gear door stuck open), why wouldn't the flight continue on to the destination airport and burn fuel along the way? The flight time is close to the amount of time they spent circling to burn off fuel, so it's not like they get on the ground any faster by staying near their source airport.

Note that this particular plane landed safely and inspection showed no indication of any real issue with the tire, but even if it did have a flat tire, would it be any worse to go on to the destination?

I suspect that it may be just in case another in-flight emergency forces the plane to divert to an alternate airport that may not have the full emergency equipment to deal with a landing gear problem, which raises the question: if the flight had departed from a small airport with limited emergency support, would the plane travel to an alternate airport with better emergency support?


texts:
Wikipedia lists the prices for F-16 as:

F-16A/B: US\$14.6 million (1998)[4]
F-16C/D: US\$18.8 million (1998)[4]

However, this is clearly outdated, and I suspect that the aircraft in the worst conditions are being used for these conversions.
It would be interesting to see a ballpark figure out the actual worth of these drones, excluding and including the conversion process.


texts: Is there a specific aviation term for suicide by pilot?

texts:
CFIT, controlled flight into terrain, refers to an aircraft being unintentionally flown into the ground.

Is there any term specific for suicide by pilot?  CFIT would not apply to that situation.


texts: What is the relationship between angle of attack and wake turbulence?

texts: It is said that when the preceding airplane is heavy, clean, and slow, wake turbulence is much hazardous due to greater angle of attack is requried. However, why does increasing angle of attack result in increase in wake turbulence? (or wing tip vortices)


texts: Is there a name for the area for aircraft to back track near the runway threshold?

texts:
Some airports have an area, on the threshold, used to back track the aircraft, mainly because of the their wingspan, they look like a half wheel.
Is there any designation for this area?


texts: Why does a pilot want to hold a Squawk Code when leaving Class B airspace?

texts:
I was listening to liveATC today... Controller clears this guy into the class B for a transition and throws him a code. Some time passes and the pilot has now transitioned the bravo and is leaving the airspace. The conversation goes roughly like this:

ATC: N12345 are you going to want a handoff?

N12345: No sir but we'd like to hold our code

ATC: Okay, N12345 you are leaving my airspace, radar services terminated, squawk VFR, frequency change approved, see ya!

Now, I guess this boils down to two questions:
1) Why would he want to keep his code if he's not being handed off to another controller? What difference does that make?
2) Why did the controller still say to squawk vfr, even if the pilot wanted to keep his code and the controller said that's fine? Didn't the pilot go against an atc order by keeping his code and not squawking 1200?

I'm a sport pilot and have yet to use flight following (nor do I have my class B endorsement), so maybe I'm just missing something due to lack of exposure!


texts: Is an ultralight aircraft allowed to fly near Class B airspace?

texts:
May an ultralight vehicle operating under FAR part 103 operate within Class G and E airspace while within the mode C veil surrounding a Class B airport?

Quoting directly from Title 14 CFR 91.1 Applicability

  FAR 91.1(e) This part does not apply to any aircraft or vehicle governed by part 103 of this chapter, or subparts B, C, or D of part 101 of this chapter.

Part 103 addresses airspace in this way
103.17 Operations in certain airspace

  No person may operate an ultralight vehicle within Class A, Class B, Class C, or Class D airspace or within the lateral boundaries of the surface area of Class E airspace designated for an airport unless that person has prior authorization from the ATC facility having jurisdiction over that airspace.

Where can I find a restriction that applies to ultralight operation within the mode C veil but still in Class E or G airspace?


texts: Why is there a relationship between maneuvering speed and weight?

texts:
Could you explain the relationship between maneuvering speed and weight?
Why are they linked?


texts: How to measure the aircraft maintenance cost of a operator? What tool or mechanism can be used to measure such performance? Or what index can be used to determine the performance?


texts: Does the crew have a professionally mandated responsibility to inform passengers of a potentially fatal emergency?

texts:
This follows on from the question here on an incident wherein a passenger asked crew about an aberrant situation during a flight.

Gathering from the answers to the question, flight crew's priority is to handle the emergency, and part of that is keeping passengers cooperative and calm, whether by informing them of details or perhaps omitting them in the interest of maintaining decorum.

However, in the case of a potentially fatal emergency, wherein passenger death is probable, despite the interest to maintain calm, does the crew have a professionally mandated responsibility to inform passengers? There are obviously moral and ethical motivations for this, but these might be beyond the scope of the site and as such I am asking how these issues are dealt with.

By "professionally mandated responsibility," it can be by laws in the appropriate jurisdiction, regulations and internal policies by the airline, common practice, or guidelines set by an aviation body.


texts: How does bank angle differ from roll angle with respect to stability in fixed-wing aircraft?

texts:
I would like a clarification on bank angle and how its different from roll angle with respect to to fixed wing aircraft. It is my understanding that the bank angle is a result of rotating the aircraft body to the stability frame, implying that if the angle of attack $\alpha$ and the side slip angle $\beta$ are zero then, and only then the bank and angle and roll angle are the same. Based on Stevens and Lewis Aircraft Control and Simulation (which doesn't define bank angle) the rotation from body to stability(wind) frame is given by
$$
C_{w-b} = \begin{bmatrix} &\cos\alpha \cos\beta & \sin\beta & \sin\alpha cos\beta \\ &-\cos\alpha\sin\beta & \cos\beta & -\sin\alpha\sin\beta\\ &-\sin\alpha & 0 & \cos\alpha  \end{bmatrix}
$$

Therefore, the bank angle $\mu$ I think is given by:
$$\mu \triangleq \begin{bmatrix} &\cos\alpha \cos\beta & \sin\beta & \sin\alpha \cos\beta \end{bmatrix} \begin{bmatrix} \phi \\ \theta \\ \psi\end{bmatrix} $$

where $\phi,\, \theta,\, \psi$ are standard aerospace Euler angles defined based on a 3-2-1 rotation.
My specific questions are:

1) is my understanding and calculation of bank angle correct? If not can someone point me to a good resource for this. I was surprised to be able to find a clear definition and formula quickly.

2) by multiplying the second and third row of $C_{w-b}$ with Euler angles we obtain a set of other two angles relative to stability frame. Do these angles have any names or specific role in aerospace dynamics/control?


texts: How does SLATS/FLAPS retraction damage the RTLU mechanical stop if we retract them after the ADIRS are set off?

texts:
From the A320 After landing FCOM NORMAL PROCEDURES:

  To avoid damage on the RTLU (Rudder Travel Limit Unit) mechanical
  stop, the SLATS/FLAPS should be retracted before all ADIRS are set to
  OFF simultaneously.

What happens if the SLATS/FLAPS are retracted after the ADIRS are set to OFF? How will the RTLU be damaged?


texts: Why does the Boeing 787 use Cabin Air Compressors (CACs)?

texts: What are the advantages of this new air conditioning system compared with the traditional engine bleed systems? More engine output power, or easier adaption to future aircraft design?


texts: What are the best practices for gathering preflight weather and information?

texts:
As a VFR student pilot, I'm still developing a pre cross-country flight routine. Weather has without a doubt been the most difficult portion of my preflight information to digest, as there are so many different sources and formats for it.

What are the generally acknowledged best practices (and sources) for assembling a complete understanding of all weather pertaining to a cross-country flight in a timely manner?

EDIT: This question is primarily focused within the continental United States, although answers pertaining to any region are more than welcome.


texts: What are the equations to compute takeoff and landing distance?

texts:
I am flying a Piper 28-336 Dakota. Based on this paper I was able to reproduce the take-off distances from the POH and incorporate the calculations directly in Excel. It can be seen that the effects of temperature and weight on the takeoff distances are not linear and can be approximated by (with no wind correction and based on the above paper)
$ReferenceDistance\times[(1-Altitude)/145442]^{5.2}\times(273.15+15)/(273.15+Temperature)]^{DensityRatio}$$\times(Weight/3000)^{WeightRatio}$

However for the landing distances it seems that the above formula does not work as the landing distance seems to be more "linear" than the takeoff distances.

Can anyone provide the precise equations to be used for computing the landing distances as a factor of altitude, weight, temperature and winds? Or references that include those equations?


texts: What is this 'ball' in front of the cockpit of some fighters, e.g., an Su-57?

texts:
What is the lump/ball thing visible below and to the left of the canopy in this image of a PAK FA (which became the Sukhoi Su-57), and what is it for? It's also seen on other fighters.

Image source


texts: Is there a limit to a subsonic ramjet's pressure ratio?

texts:
Subsonic ramjets have high specific fuel consumption. This indicates to me they must have a low pressure ratio.
Is there a limit to how high pressure ratio one can achieve with subsonic air? Why can't you just increase the area ratio between inlet and the diffuser exit?


texts: Which one is more effective produce power of this two turbine's location?

texts: Consider we have the exactly same turbine which is possible to be mounted to the tail (left picture) and to the wing (right picture) as picture below. Which one will produce more power to the airplane? Need physics analysis.


texts: What is this aircraft seen at Peachtree City, GA?

texts: Sorry for the poor quality, but this jet was taking off from Peachtree City Regional on Sunday 13 May. Anyone know the aircraft?


texts: Would an airliner be allowed to take off in snow?

texts: Im going to fly to Tucson tommorow. The weather is telling me its going to snow in Denver. So would snow cause a delay or are airliners allowed to take off in this kind of weather?


texts: What measures were taken to keep Soviet airline pilots in the Soviet Union?

texts:
How did the Soviet Union keep airline pilots from leaving the country?

It seems like it would have been pretty easy to do since the pilots are already in the air. And I would guess at least some flew close to the borders.


texts: Which approach category minimums should I use when conducting an instrument approach?

texts:
FAR 91.3 says:

  Aircraft approach category means a grouping of aircraft based on a
  speed of VREF, if specified, or if VREF is not specified, 1.3 Vso at
  the maximum certificated landing weight. VREF, Vso, and the maximum
  certificated landing weight are those values as established for the
  aircraft by the certification authority of the country of registry.
  The categories are as follows—

  (1) Category A: Speed less than 91 knots.

  (2) Category B: Speed 91 knots or more but less than 121 knots.

  (3) Category C: Speed 121 knots or more but less than 141 knots.

  (4) Category D: Speed 141 knots or more but less than 166 knots.

  (5) Category E: Speed 166 knots or more.

So an aircraft category never changes because it is always Vref at max landing weight.

What if I fly an approach at a speed that falls into a different category?  For instance, a jet may land at significantly less than this speed if very light, or more than this speed if landing with less than full flaps due to a failure (or any other operational reason).  Which minimums do you use then?


texts: Are flight attendants paid in the same way pilots are paid?

texts: I understand that airline pilots are generally paid for their time "in flight", which means the clock starts when the aircraft begins to move away from the gate. Are flight attendants paid in the same way?


texts: Do commercial jets ever make 360 in the pattern for separation?

texts:
It's not uncommon for GA aircraft to circle in the pattern for separation purposes. Does that ever happen to big commercial jets?

Imagine an airliner were cleared for a visual yet forced to execute a go-around and instructed by ATC to take a pattern. When there's another traffic on final, is it a viable option for ATC to instruct the jet to make a left or right 360 for the traffic on final? Does it actually happen in the real world?


texts: How much might soft skin reduce aircraft skin friction?

texts: According to Peter Kampf's answer here, soft skin can damp a (vibrational?) mode that cause laminar flow to become turbulent. Thus, it could help delay boundary layer transition. My question is, for a modern large transonic jet (737+), how much may this reduce drag?


texts: How many VHF system can be in MEL for an A340?

texts:
How many VHF (Voice Communication) system can be in MEL for A340 aircraft?

What are the guidelines to decide that and is it different for aircraft operating under FAR 121, 125 and 135?


texts: Which way should I rotate the propeller of a C172?

texts: During pre-flight which direction should I be rotating the propeller of a Cessna 172 if I need to reach the alternator belt?  I thought I was told "In the direction it rotates during flight"; however I feel there was some misunderstanding. Isn't there the possibility of accidentally hand propping if I do it that way on a warm engine? Today I rotated it clockwise in the direction of the blade and it kicked over and popped me in the knee (leg shouldn't have been there - lesson learned!) Please help me clarify!


texts: What callsign would a medical emergency flight use?

texts:
I see medical emergency helicopters taking off and landing several times a day from the hospital near my office. As I understand from an earlier question, they are probably flying VFR, below controlled airspace and likely without ADS-B.

I would assume, however, that these flights are in touch with the local ATC, and they are certainly announcing their presence on the locally monitored channel(s). Is there a particular set of call signs or other indicators that are used by these flights to indicate to other traffic that, while this flight itself is not in any sort of mayday situation, it needs priority handling and that everyone else needs to get out of the way as lives depend on the speed of this particular flight?

I am asking particularly for the USA/FAA, but would be interested to know if there are differences in other countries around the world.


texts: Where can I get an list of ATC phraseology terms in Spanish?

texts: I'm considering flying in a Spanish-speaking country and would like to have a passing familiarity with how to communicate with ATC in Spanish. Is there an ATC English-to-Spanish dictionary?


texts: Where did the terms QNE, QNH, and QFE come from?

texts:
In the aviation community (at least outside North America), the terms QNE, QNH, and QFE are used to describe standard pressure, local altimeter, and field elevation, respectively.

But what is the origin of the "Q" code names?


texts: What mental health standards must a candidate meet in order to qualify for a pilot's medical certificates?

texts:
What are the mental health standards (if any) that a candidate pilot must meet in order to qualify for a medical certificate?

Answers for Canada, the US, and Europe would be particularly interesting to me.


texts: How do weapon pylons attach to a fighter's wings? I'm particularly interested in the inner structure.


texts:
While listening to Air Crash Investigations, the pilots used the 24-hour format in a different way than we do.

Example: 07:57 hrs would be said as oh-seven-five-seven hours (which makes it a little confusing as one might think of them as co-ordinates) instead of saying 7-hundred and 57 hours.

What is the correct way for pilots to say the time?


texts: Can an Airbus A380 or Boeing B747 fly with only 2 engines?

texts:
What would happen if, during cruise at a high gross weight, one of these airplanes suffered a double engine failure:

With one failed engine on each side (leaving one working engine on each wing)?
With both failed engines on the same side (leaving the aircraft with two working engines on the left wing and none on the right wing, or vice versa)?

I know that airplanes with two engines can still fly with only one working engine (by using the rudder to counter the yawing moment created by asymmetric engine thrust, placing the aircraft into a sideslip).


texts: Given the similarities between Lift and drag and their very similar relationships to the density, surface area, and airflow velocity, could one, in theory, describe aerodynamic lift as a kind of drag where most of the force from lift is just directed in the vertical direction where this vertical component of the force opposes gravity?


texts: What are the reasons for this radial piston engine shut down procedure?

texts: In a radial piston engine, before the engine is shut down the rpm is brought to a considerable high power setting of approximately 1950 rpm. This is to burn the unburnt carbon in the spark plugs. Are there other reasons for this specific power setting to be selected before the engine shuts down?


texts: Why do we seldom see small unmanned aircraft with gasoline engines?

texts:
Most commercially available FLYING WINGS (RC aircraft or UAVs) are battery powered. Why aren't there more with with gasoline engines?

PS: Sorry I edited. The question is specific about flying wings configuration.


texts: Should an emergency field landing be performed with landing gear down or up?

texts:
Suppose you are flying an aircraft with retractable gear and have to make an emergency landing on that big "flat" stretch of grass up ahead and have only one shot at it, what's better, do it with wheels down or up.

Obviously, if the ground is flat enough, wheels down may be great and may even let you recover your aircraft basically undamaged. However, hitting a rut or other obstacle with the gear could have some rather unfortunate consequences.

That left me wondering which is better, dropping the gear and hoping for the best, or a controlled belly landing. (Also hoping for the best!)

I also wonder what, if any, instruction is given on this situation during flight training.


texts: Why don't nose landing gears have brakes?

texts: Nose brakes can help the aircraft in braking and it can also help in reducing the travel on the runway length. So why don't we use brakes in the nose landing gear?


texts: Why is the V1-speed callout automated in modern commercial aircraft while VR is not?

texts: In some modern aircraft such as the Airbus A380 or Boeing B787, the callout of the V1 speed is automated through a synthetic voice, based on the V-speeds entered into the flight management system. However, the rotate speed VR is still announced by the Pilot Monitoring. Why is the VR callout not automated?


texts: What is qualitative relationship between surge line, stage characteristic and throttle characteristic?

texts:
I have referred to standard author books and online tutorials but I am still quite confused about how the Stall and Throttle characteristics lead to Surge.

1.  Why and how does the throttle characteristic affect the compressor performance because as far as i know, the next consecutive element in an engine after a Compressor is a Combustor, and the throttle comes at last,after combustor and turbine,  assuming throttle is same as nozzle (if not please correct me).

Assume i am talking about turbojet engines and Axial compressor, just to have a picture in mind.

2. How does the throttle characteristic curves come out to be like that?

And why does the mass flow decrease when we throttle the compressor?

3. I am also unable to grasp the concept which causes the evil fluctuations in the flow during surge, which leads to reverse flow and damage of the components.

Source:- Hill Peterson- Thermodynamics of Propulsion.

Someone please explain the concepts as much as possible.


texts: What modifications would be required to use a DHC-6-400 for Carrier Onboard Delivery work?

texts:
In the spirit of our small airplane landing on a carrier question, I decided to up the ante slightly in a couple of ways.

Let us say some enterprising foreign navy has found a small flattop under their Christmas tree this year, and is in need of some aircraft to fly off it.  Of course, tactical aircraft are a necessity, and to that end, they could obtain some used A-4s as a starting point for their fledgling naval aviation branch.  However, there are other important aircraft on a carrier deck, one of them being the Carrier Onboard Delivery plane.  A bright young naval officer there decides "Hey, we should see if some small civil planes might work for what we need", and does a bit of research, stumbling upon the DHC-6-400 with its widespread support base, ease of maintenance, good STOL performance, and current production availability.

How much modification would our enterprising foreign navy need to ask Viking Air to do to their order of DHC-6-400s to be fully usable from a carrier deck?


texts: What additional functionality is provided by the F-14 nose pitot, absent in early models?

texts:
Early model F-14A had no nose pitot:

... but they seem to have quickly acquired them sometime in the late 1970s. The Iranian F-14s have them, and it's quite hard to find a picture of an F-14 without a nose pitot.

This is the nose pitot that appears on the majority of F-14s:

I believe the nose pitot measures angle of attack, a measurement I would have thought was critical to a big carrier-based aircraft like the F-14 from the outset.

So, why were the nose pitots introduced, and what effect did it have on the nature of piloting an F-14?


texts: Is it worth reporting that I saw a green laser being pointed at the aircraft as a passenger?

texts:
I was on approach to Vienna yesterday evening when I observed two 2-second green laser flashes 5 seconds apart from one of the rear passenger windows of the B737 where I was seated being pointed at the aircraft.

I'm wondering if and what I should do since green lasers are dangerous, and I'm convinced the aircraft was being targeted. Should I report this to the relevant authorities? Is it very common or a rare occurrence? The co-pilot didn't seem very bothered about it in any case and he hadn't seen it.

Updates:
20th December 2014: Sent an email to the relevant Austrian authorities. Will see if I get a reply.
22nd December 2014: Sent a report to AustroControl as well.
8th June 2015: No reply to date.


texts: What's Concorde's engine fan blade tip speed at full thrust?

texts: I can't find anything on the web about the Concorde's Snecma engine fan blade tip speed at full thrust. Any ideas?


texts: Would all these three things have the exact same effect on the flight duration of a glider?

texts:
Consider a glider trimmed to fly at some given angle-of-attack, gliding in smooth air (no thermal convection, ridge lift, wave lift, etc.).  If air density is somehow kept exactly constant in all cases, and the glider is launched from the same initial altitude relative to the ground in all cases, would the flight duration be the same in all three cases?  (A yes/no question.)

Extra weight has been added to the glider, exactly at the CG, doubling the glider's weight.
We've increased the value of the gravitational constant from 9.8 m/s/s to a higher value (twice as high).
We've caused the earth (and atmosphere) to steadily accelerate straight “up”, at 9.8 m/s/s, thus creating an apparent increase in the gravitational constant (to an apparent value double the actual value).  (Acceleration starts well before the glider is launched, not mid-flight.  Glider is also accelerating along with everything else at instant of launch, i.e. the atmosphere isn't rushing up past the glider at the instant of launch.  For example the glider could launch by rolling off a ramp mounted on a high tower connected to the ground.)

(Edit: to make this more clear, imagine that a giant rocket engine attached to the other side of the earth is causing this acceleration.  The earth itself is the only thing that is being directly acted on by the accelerating force; the atmosphere and glider each experience the results of this acceleration in a less direct manner.)

Also, if “yes”, then a second question — launched in equilibrium (exactly at its steady-state trim speed for the existing conditions) from a given height, would the glider stay up for a longer duration or a shorter duration after we've made one of these changes?

The intent of the question is to compare the steady-state in-flight dynamics, not some difference  relating to some possible slight variation in the initial kinetic energy imparted at the instant of launch, etc.  In each case, the glider is understood to be launched at its steady-state trim speed in relation to the existing conditions.


texts: How do I determine the center of gravity on aircraft?

texts: What are the parameters considered and what formulas are used to find the Center of Gravity on an aircraft?


texts: What is the maths behind the descent rate calculation?

texts:
The descent rate calculation states that descent rate is calculated by 'groundspeed / 2 * 10'.

Another document stated that the ground speed should be multiplied by 5 (or more accurately 5.2) to acquire the descent rate. The 5.2 value is found by finding the gradient for 3 NM for 1000 feet (based on the 3:1 glide ratio), which is 5.2% (found using tan of 3 degrees). The document can be found here: https://www.ivao.aero/training/documentation/books/SPP_APC_Top_of_descent.pdf

My question is: How was the formula created? It's interesting that I can't find any info on this on the internet. Can someone show the maths behind this formula?


texts: Is using flaps the same as increasing the AOA?

texts:
The purpose of trailing edge flaps is to give the aircraft more lift at lower speeds.

But do simple flaps beneficent more than increasing the angle of attack?

The image looks like part of the wing just had it's angle of attack increased, and the other part did not.

Also considering flaps lower a wings critical angle of attack, and increasing the lift coefficient are they really just another way of changing the angle of attack?

If so why do smaller planes use them instead of setting up the landing gear to takeoff/land with greater angles of attack?


texts: How are electronic instruments and other equipment powered in a glider?

texts: Radios and other electronic devices must be battery-powered. What sort of battery - and does its capacity impose a limit on flight duration, or can they be recharged in flight with a turbine?


texts: Why do suborbital planes feature H-tail and/or large wingtips?

texts:
Spaceplanes that are suborbital are mostly supersonic and feature H-tail or rather large wingtips. This looks to be similar to a H-tail configuration but I'm unsure abut how it works, which is why I say large wing tips. They focus on a delta wing and elevon for the pitch and roll and yaw seems to be controlled using this.
For example look at the following spaceplanes.

References:
1. https://www.virgingalactic.com/articles/VSS-Unity-First-Powered-Flight/
2. https://www.sncorp.com/what-we-do/dream-chaser-space-vehicle/
3. https://www.flyfighterjet.com/xcor-lynx-space-flight


texts: Do existing large commecial jets make use of differential thrust to control yaw?

texts:
Does existing Avionics / Control Systems on large Commercial Jets make use of differential thrust of engines much?

e.g. I was contemplating applications of this sort: Normally the thrust provided by each of multiple jet engines will be different due to difference in age, wear, build etc. and this is usually compensated by rudder trim.

But instead, would it be feasible for a controller to detect the slight yaw moment and modulate the throttle setting to compensate thereby negating the use of rudder trim?

What about a more general strategy in which the use of rudder trim, or more extremely rudder itself is reduced via automated differential thrust modulation of jet engines? i.e. Using differential thrust not just yaw compensation but yaw creation as well?

Do such systems already exist? Or is there a fundamental flaw in my reasoning that make these ideas not viable?


texts:
What is the difference between ACARS and ADS-B?

For weather information in-flight or pre-flight which one is used?


texts: How does the noise of a 2-to-4-seat helicopter compare with that of a similarly-sized fixed-wing aircraft?

texts:
We are considering allowing helicopters on our private airstrip (2600 ft strip). Noise on the ground (and approach) is the concern from the community.

Does anyone know approximate dB ratings for a typical 2-4 seat helicopter vs. a 2-4 seat fixed-wing propeller aircraft? I know there is no exact comparison, but just an approximation would be helpful.


texts: What's the pilot's typical reaction time to co-pilot's callouts?

texts:
How long does it take on average before a pilot initiates an action in reaction to a co-pilot's callout? Are there any research data on this subject?

I'm asking this question in relation to the V1 speed, or more specifically to figure out whether it's a reasonable procedure to require pilots to continue takeoff (even) when an engine has failed one or two seconds prior to reaching the V1 speed, taking into account their reaction time.


texts: Single Engine operation on Twin Engine aircraft

texts:
I recently came across ETOPS and I wanted to know:

How does a twin-engined aircraft  balance out the lack of thrust on one side in the event that one of the engines is non operational? Any information is appreciated.

Apologies if this has been asked before or if it doesn't comply with other standards. I'm new around here and couldn't quite find anything that addresses what I wanted to know. If someone can point me in the right direction, I'd appreciate it.


texts: Where to download NAT Track Message (original and official source)?

texts:
I am studying about North Atlantic tracks.
I know the message is usually distributed to interested parties via AFTN and is published by Shanwick or Gander. I would also like to get such information from the same source.

Where can I download NAT Track Messages in their original format (I guess it is the AFTN Message Format)?

Note: I want the official and original message possibly. I don't want other websites that show me NOTAMs or other formats that are not official. I am interested in the original message.


texts: Are the N1 and N2 tachometer generators installed on 727 / JT8D engines line replaceable units?

texts: Each JT8D engine on a 727 has two tachometer generators as part of the engine tachometer system to measure N1 and N2 speeds. Are these generators line replaceable units? How long would replacement of just one generator take?


texts: What is the process of 'blending' that is used as part of jet engine maintenance?


texts: Does it ever happen that increasing the prop RPM without moving the throttle actually decreases the thrust and power delivered to the airframe?

texts:
A) In an airplane with a piston engine and a constant-speed prop, flying at some given airspeed with the manifold pressure and RPMs in a typical cruise configuration, would it ever happen that increasing the prop RPM higher and higher without moving the throttle would at some point actually start to decrease the thrust and power delivered to the airframe?

Assume no electronic engine controls such as FADEC.

I'm imagining a case where flattening the pitch of the prop blades would decrease the thrust and power delivered to the airframe, because the prop blades would be meeting the local airflow at a lower angle-of-attack, despite the increase in RPM.  I guess an extreme case would put the prop blade at a small negative angle-of-attack to the local airflow, so that the prop was acting to drive an increase rather than a decrease in the engine RPM-- obviously this would increase the RPM but would decrease the thrust and power delivered to the aircraft, at least in the forward direction.

B) It occurs to me now that such a thing might happen at lower throttle positions but not at higher throttle positions.  So a second part of this question is, on final approach with the throttle at idle, is it true that the prop exerts more of braking effect on the airframe when the prop lever is set for high rpm than when the prop is set for low rpm?

C) And the third part of this question is, for some given airplane cruising at some given airspeed with RPM and manifold pressure initially "square", what is an example of the highest initial manifold pressure at which we might find that advancing the RPMs higher and higher without changing the throttle setting might eventually cause a drop in the power delivered by the prop to the airframe?  Or is this something that would only happen at very low power settings, such as would be used in a descent, and would never happen at any power setting capable of sustaining level flight at any airspeed?  (This is basically a more refined version of part A.)

The intent of the question is that the advance in the RPMs is intentional and goes no further than the max allowable RPM of the engine and prop.  Clearly a "runway" prop would be an extreme example of these dynamics but the question is intended to be constrained to the normal allowable operating envelope of the prop and engine.

Some related questions and answers on ASE--

Manifold pressure vs rpm vs power obtained and more about constant speed prop

On a constant speed propeller, how is blade pitch related to airspeed and efficiency?


texts: If AWOS reports IFR conditions but I can see at least three miles, can I take off or land?

texts:
The uncontrolled airfield where I have my airplane gets foggy in the morning occasionally, but there have been times when there is just a little fog where the AWOS station sits so it reports 1/4 mile visibility and undetermined ceiling, yet the runway farthest from it is clear and there are no clouds. My flight instructor and ground school instructor said you must always comply with the AWOS reported conditions, yet my flight examiner (I just got my private pilot license) said a pilot can overrule the automated station if it is clearly wrong. Machines can break and are limited to where their position is.
FAR 91.155 talks about visibility, but doesn't mention how it is determined. Flight visibility is determined by the pilot, so I interpret this to mean he can overrule the AWOS if it is clearly wrong.

(d) Except as provided in §91.157 of this part, no person may take off or land an aircraft, or enter the traffic pattern of an airport, under VFR, within the lateral boundaries of the surface areas of Class B, Class C, Class D, or Class E airspace designated for an airport—
(1) Unless ground visibility at that airport is at least 3 statute miles; or
(2) If ground visibility is not reported at that airport, unless flight visibility during landing or takeoff, or while operating in the traffic pattern is at least 3 statute miles.
(e) For the purpose of this section, an aircraft operating at the base altitude of a Class E airspace area is considered to be within the airspace directly below that area.

Another question about (e), after reading it about 5 times: my airport is class G up to 700 feet, then turns into class E above that. Does (e) mean that if I am at 700 feet AGL, I am still in class G? Of what significance is this?


texts:
This question came up after reading the following comments on the answer to this question: Raising the flaps right after touchdown. Good or bad?

Philippe Leybaert Jan 20 at 23:00

  The retractable landing gear is an excellent point. It makes perfect
  sense. I've read a few stories of pilots retracting the gear after
  landing instead of raising the flaps.

voretaq7♦ Jan 20 at 23:02

  The retractable landing gear issue is particularly notable because
  early in the landing roll you may not have enough weight on the wheels
  to activate the squat switch that prevents you from retracting your
  gear while you're using them to hold the plane up. Your perfect
  landing could turn into a nice, smooth gear-up incident if you bump
  the wrong switch.

Questions

How does the squat switch work (which prevent gear up on the ground)?
Are there any reports on issues of gear up on ground? (I only know
one)?


texts: What is the average deviation from the PAPI glide slope at the threshold?

texts: If one approaches with three red and one white light what will be the average deviation from the standard threshold height of 50 feet?


texts: Why doesn't EVA Air BR087 (Taipei to Paris) follow the shortest path?

texts:
I've noticed that the flight BR087 from TPE to CDG doesn't follow an orthodrome.

Instead, it seems to take great pains to avoid the Chinese airspace entirely.

Why? EVA Air has other flights connecting Taiwan to China.

For instance, a similar flight KLM808 follows the orthodrome more closely :


texts: Does aircraft/ATC get any information directly from a weather balloon?

texts:
We have been launching radiosonde (a meteorological instrument containing GPS and other sensors to measure meteorological variables attached to a balloon filled with Hydrogen) to obtain meteorological data of the atmosphere.
This radiosonde transmits the information to a ground station we have in a frequency close to 400 MHz (well, this is what we uses, not sure about others). We frequently update the vertical height, direction, bearing position etc to our nearest ATC.
I was told that ATC and aircraft get information from the radiosonde directly (I am not sure what sort of information they get) other than what we give to the ATC.
So, I want to know whether ATC/aircraft get information directly from a radiosonde and if they do, what sort of information do they get?
I am not concerned about the radiosonde's meteorological data going into the weather models for forecast products that is available to aviation industry. What I need to know is if ATC/aircraft can know the position of the balloon/radiosonde directly by the information the radiosonde transmits?
In essence, can ATC/aircraft track a radiosonde without inputs from the agency that launches/manages the radiosonde?


texts: What would be the impact of replacing the engines on the 737 MAX, not just reworking MCAS?

texts:
There has obviously been a lot of focus on the MCAS failure following from the 737 MAX crashes. However, the MCAS appears to be a compensating control for design decisions, specifically the replacement of the CFM56-7BE engines on 737NG with the much larger, more efficient LEAP-1B. That in turn necessitated a higher ground clearance.

In lieu of redesigning the landing gear to provide greater clearance (and raising the overall height of the plane), the engine pylon was redesigned, moving the engine further ahead of the wing and closer in line with the wing surface. There were other changes as well.

The re-positioned engines changed the thrust line. The resulting control characteristics were compensated for in software, with the MCAS addressing a very specific negative flight characteristic.

Notwithstanding the new engines being more efficient (resulting in lower operating costs), is it possible and what would be the impact of retrofitting the existing fleet of 737 MAX with an engine and pylon in the previous position ? Could for example, the CFM56-7BE and pylon be retrofitted?

There are plenty of plane models offered with multiple engine configurations, though I imagine they are fit off a similar pylon / housing.

If I were an operator of MAX fleet in which the public has lost confidence in flying on, I'd like some other option than scrapping the fleet. Edit/Addenda: I don't know anyone is planning to scrap the fleet and it's far too early to suggest what the final outcome may be as this story plays out. There have definitely been order cancellations, orders lost and questions surrounding the plane's certification. You can't cancel an already delivered/completed order; it would be difficult to force Boeing to buy them back and replace them (with what?). IF Boeing offered to "retrofit the MAX as an NG-like", it might be the best possible outcome for all.

It certainly seems less drastic than Boeing starting from a completely different base design or losing customers to Airbus.


texts:
In this situation, I would be flying from Richmond Executive-Chesterfield (FCI) to New Kent Co (W96).

Can I land at an uncontrolled airport under class C without talking to ATC?

Picture source: SkyVector


texts: Why are the A300/310’s electric pitch trim switches inhibited with the autopilot engaged?

texts:
The A300/A310, like most other aircraft (except for some small general-aviation aircraft), has an adjustable-incidence-angle horizontal stabiliser, which is used to trim the aircraft in pitch (for instance, to change the aircraft’s speed or compensate for shifts in its center of mass) without the need for large elevator deflections (which would increase the stress placed upon the elevator control linkages and actuators, shortening their lifespan, and, if the autopilot was flying the aircraft, would  result in large pitch excursions upon autopilot disconnect as the elevator returned to its neutral position).

There are three methods by which the horizontal stabiliser can be moved:

The A300/310’s autopilot, like those of most other autopilot-equipped aircraft, automatically trims the aircraft in pitch when engaged; it moves the stabiliser by applying power to a set of electric motors which rotate the stabiliser jackscrew, moving the stabiliser’s leading edge up or down.
In manual flight, the aircraft is usually trimmed by using two sets of electric trim switches (one on each of the two control yokes), which, like the autotrim system, apply power to a set of electric motors which rotate the stabiliser jackscrew.
As a backup, a manual pitch trim wheel is mounted on the center console between the pilots; this wheel is connected to the stabiliser jackscrew via a cable mechanism, and, when used, manually rotates the jackscrew directly.

If the autopilot is engaged, the electric pitch trim switches are inhibited, and cannot be used to trim the aircraft; the aircraft can only be manually trimmed by rotating the manual trim wheel, which disconnects the autopilot.  As a result, in the event of an autotrim runaway, the pilots need to take one hand off the yoke to manually trim the aircraft against the malfunctioning autotrim.  This is especially critical in two specific autopilot modes (LAND and GO-AROUND), where pulling or pushing on the yoke to use the elevators to manually counter the autotrim-induced pitching moment will not disconnect the autopilot if the aircraft is less than 400 feet AGL (and, originally, would not do so no matter what the height AGL); indeed, doing so will cause the autotrim to trim further and further against the pilots’ control inputs, exacerbating the problem at a time when maintaining pitch control of the aircraft is (due to the very limited altitude available with which to work with) far more critical than in most other phases of flight.

So why are the yoke-mounted electric pitch trim switches inhibited and inoperative whenever the autopilot is engaged?


texts: Can someone identify if this is a Boeing or an Airbus?

texts: I would like to know if this is a Boeing or an Airbus. Maybe there is an Aviation Wizard out there. It's an EasyJet plane.


texts: Where can I find details about a Cambridge Scientific Instruments Fuel/Air ratio Indicator?

texts: In our restored Harvard Texan T-6 WW2 trainer aircraft, a Fuel/Air Ratio Indicator was installed. We cannot locate the wiring diagram of this system or information for the Cambridge Scientific Instrument Co. The instrument is P/N. 11622-1 Spec 94-27992. Please help us with the required information, or the indicator's pinout and functions.


texts: Why does a rectangular wing stall first at the root? as opposed to tapering of the wing which causes the stall at the tip and moving inboard?


texts: How do aircraft follow the tarmac lines while taxiing?

texts: How does the pilot determine he is on the yellow taxi line at all times, since he doesn't have a direct view to the ground below? I am sure there must be some equipment, but I just don't know what.


texts: Does the temperature of the body of an aircraft increase its efficiency?

texts:
I am working on a prototype for an airplane. I was wondering, can the temperature of the body of the plane make it more efficient? If the structure is at 25°C, does it need less energy to maintain a steady state flight than a structure at -20°C?

I had this idea about excess energy that could be collected during the day, and was wondering if there is any chance that when the batteries are fully charged and there's still excess power being generated, I could use it in order to increase the performance of the aircraft.


texts:
I was watching a video where a plane an MD-82 descended 18,000 feet per minute and crashed into a mountain.
The plane was not upside down/on its side/spiraling- it had about a 5 degree pitch up the whole time.
My question is: Would this rapid descent kill you, or at least make you pass out? What is the descent rate that would simply just make you go unconscious?


texts: Why is IndiGo adding A320NEOs more aggressively than any other airline?

texts:
Currently there are about 45 NEOs with PW engines and 6E operates 17 of them. These PW engines have notoriously reported many engine issues and 48 of them have been replaced so far. IndiGo itself has faced 6 engine replacements so far.

Usually, we see that when an Aircraft type reports so many problems, airlines usually halt deliveries until the manufacturers fix them. Even with A320Neo, Qatar Airways has cancelled their order for PW NEOs and Lufthansa is deferring the deliveries.

Why is it then IndiGo is adding them so aggressively? It plans to add 4 NEOs in March 2017 only.


texts: Does True Course, Magnetic Heading, or Magnetic Course determine cruise altitude?

texts:
Imagine I plot a course on a sectional chart. The straight line plotted reads a 345° course. The nearest isogonic line is 14° W (so +14°). Weather information calls for a wind correction of +2°. Since 345+14+2=1, my magnetic heading would then be 001°.

What course or heading am I to use for choosing my cruise altitude (considering the east/west rule)? Do I use the true course that I plotted on the sectional, the magnetic course, or the magnetic heading?


texts: What technical problems stopped scramjets from being used on hypersonic aircraft?

texts:
I have been researching hypersonic aircraft and scramjet engines after running a few calculations looking at ramjet/rocket hybrids for making single stage to orbit vehicles. After doing the analysis and reading a little bit of the development history, I am still a little baffled as to what stopped the development of the engines to get deployed on aircraft and rocket.

What is keeping the engine cool enough to not melt or fly apart at design speeds? Was it making sure the inlet compressed the air quickly enough without slowing the flow with a normal shock? Was it making sure the structure of the engine was light enough to still produce enough thrust to fly the aircraft?

If these were the problems, why were they hard to solve? Was it that we did not know how to get enough cooling for low pressure drop? Or know how to locate shockwaves in the intake because the ratio of specific heats changes?


texts: Was this an unusual landing sequence for an airliner?

texts:
About a month ago I encountered an unusual landing during a flight from Bangkok to Krabi airport. We were flying Boeing 737.

We took off 30 minutes late. Our flight should've taken 90 minutes but it actually took less than 70 minutes so we arrived almost on time.

The seatbelt sign turned on around the 60th minute while we were still probably in 10000 meters (I don't know the cruising altitude for sure). The whole landing took less than 10 minutes. I guess the landing gear was deployed at around 6000 meters which seemed unusually high to me. The pilot also performed several rather sharp roll maneuvers and at one point he broke his descend and even entered a rather sharp climb. All this with landing gear out. I have to say that many passengers were quite terrified at the moment. The landing itself was hard but not that much.

I have been  wondering if it was a common maneuver (to decrease speed perhaps?) and would be interested to learn more about it. Does it have something to do with the flight speedup? How is it even possible to be so much faster on such a short flight?


texts: Does transition to GBAS navigation require alignment of the intermediate segment with final segment?

texts:
I am studying how the Ground Based Augmentation System (GBAS) affects the Instrument Approach Procedures, and I noticed that in ICAO's Aircraft Operations manual (8168, Volume II) it states:

  Part III, Section 3, Chapter 6, 6.3.2: "The intermediate approach segment of a GBAS procedure shall be aligned with the final approach course."

I would like to make sure if the rule concerning the alignment of the intermediate segment with the final segment implies that the whole segment (each leg of the intermediate segment) has to be aligned with the final, rather than only the last leg.

Could someone point me in the right direction?


texts: Where are the communications antennas normally located on general aviation aircraft?

texts:
In the past I have had instructors suggest that I use COM1 in the air and COM2 on the ground. The rationale was that most aircraft have the COM1 antenna on the belly making it favorable for air to ground when in the air and COM2 on the roof making it favorable for ground to ground when on the ground.

It can definitely be helpful to use the top antenna for ground communications and the belly antenna for air.

I frequently fly a late model PA-32 and I haven't found documentation on which communications antenna is which.

I also frequently fly Cessna aircraft which usually have all comms antennas on the roof.

I sometimes fly an SR-22 and my instructor suggested using COM1 on the ground and COM2 in the air. This is reverse from what I thought was usual, but indeed the SR-22 AMM shows that the COM1 antenna is on the roof with COM2 on the belly.

Is there really a rule of thumb here or does it vary so much from one aircraft to another that no rule of thumb is possible to say?


texts: When flying VFR without GPS, how do pilots know if they are inside controlled airspace or not?

texts: How do VFR pilots know whether or not they are inside controlled airspace if they don't have GPS onboard?


texts: What is the difference between ILS and VOR/DME?

texts: I have wondered many times about the difference between VOR/DME and ILS and which one is better for carrying out approaches. Why do pilots use VOR/DME when the ILS is a better option because it is precise and VOR/DME is a non-precision approach?


texts: Would it take 7 to 10 times more energy to lift a turbofan-helicopter?

texts:
I want to figure out how much energy it would take to lift a turbofan-helicopter.

For reference I started with a rotor helicopter and assumed $T=100\ \mathrm{kN}$ gross weight and $d = 16\ \mathrm m$ rotor diameter (compare S92 or AH64).

Using the propeller-formula
$$
T = ( 0.5*P^2*\eta_\text{tot}^2*\pi*d^2*\rho_\text{air})^{1/3}.
$$

with $\eta_\text{tot}^2=0.58$ (source) I get an engine-output of $P=1\,870\ \mathrm{kW}$

If I now take a typical turbofan and a take-off $tsfc$ of $10\ \mathrm{g/(kNs)}$ I get a fuel consumption of $1\ \mathrm{kg/s}$ for my $100\ \mathrm{kN}$ helicopter. If I furthermore assume 30% overall efficiency and $E_\text{Jetfuel}=43.5\ \mathrm{MJ/kg}$ I get an energy demand of $13\,050\ \mathrm{kW}$ to run the fan (neglected all the other stuff taking energy from the shaft).

Does this mean it would take 7 times the amount of energy to lift a turbofan-helicopter (with engines running at full throttle)? Or a magnitude if I assume cruise tsfc...

Does this suit with your experience? Or is there a big error/misconception in my short calculation?


texts: Has the FAA banned FPV for model aviation?

texts: On the FAA website the FAA says that you should not fly your model aircraft out of line of sight. Does this mean you cannot use FPV goggles?


texts: Can line and light maintenance be combined?

texts: Is there any possibility to combine line maintenance and light maintenance (containing A, B and C check) under the name of line and light maintenance? In real is there any company which possesses a line maintenance which carried out "A" check and so on?


texts: Where are the bags generally stored on an airliner?

texts: I don't mean carry on bags. What I mean is where are the locations of the non carry on bags on an airliner. Also does it depend on the airliner of where the bags are stored.Source:(gokaysarioz.com)