130
votes
Accepted
Why do we need to starve the engine before turning it off?
The reason is the large spinning thing on the front. Residual fuel in the engine has been known to auto-ignite (i.e. combust without a spark), causing the prop to spin, causing serious injuries and ...
- 52.9k
125
votes
Accepted
Why are fuel tanks located in wings?
Several advantages:
Wing structures are hollow and voluminous in order to provide structural rigidity against flutter and carry flight loads. This provides the space needed to store fuel.
On a ...
- 72.8k
84
votes
Why are fuel tanks located in wings?
I see what you're saying, but there's something you're overlooking in your logic. You're looking at an airplane sitting on the ground, where the wheels are near the fuselage and most of the wings are ...
64
votes
Accepted
Why do many GA aircraft not have a "Both" fuel selector?
A quote from the book of regulations, Chapter 14, part 23, verse 951(b):
...
- 68.3k
62
votes
Accepted
Why didn’t the Captain of Cathay Pacific flight 780 shut down engine 1 and land with a more reasonable speed?
You can find the full incident report here and this topic is touched upon briefly, but in short they had little to no time to entertain any other options but a full speed landing.
It was not until ...
- 100k
61
votes
Why didn’t the Captain of Cathay Pacific flight 780 shut down engine 1 and land with a more reasonable speed?
Engine #2 wasn't doing its job either
Had the situation just been engine #1 stuck at high thrust, with engine 2 normally controllable, than what you describe would be a reasonable response to the ...
56
votes
Accepted
Why do jet engine igniters require huge voltages?
In short, 40 kV isn't that much voltage for applications that are intentionally creating an electrical arc. Car spark plugs also use voltages in the tens of thousands of volts for the same reason, for ...
- 19.4k
49
votes
Why are fuel tanks in the wings filled first, and why are they used last?
Having all the payload of a plane concentrated at the fuselage creates a large bending load on the wings in order to support that weight. Storing fuel in the wings allows some of that weight to be ...
- 71.8k
47
votes
Is fuel moved around during flight on a passenger or cargo plane? If so why?
Maybe
This is dependent on the air frame and varies from plane to plane and not all planes have capability of moving fuel although most large planes do. The Concorde moved fuel all over the place ...
- 100k
39
votes
Why do we need to starve the engine before turning it off?
Combustion in a gasoline internal combustion engine for most aircraft, requires four things: fuel, oxygen, compression and ignition.
If the engine is starved of fuel, accidental combustion (and an ...
- 17.7k
37
votes
Accepted
Is there a tank priority sequence for using the fuel tanks?
Which fuel tanks are used in order of priority in aircraft?
What you're talking about, in large aircraft, is often referred to as the fuel burn schedule. Light aircraft generally do not have a fuel ...
- 39.2k
36
votes
Why aren't "fuel polishing" systems removing water & ice from fuel in aircraft, like in cruising yachts?
The simple answer is weight/risk/added complexity: the systems are heavier than they are worth for the problems they avoid in aircraft.
While ice blockage has been an issue for aircraft in the past, ...
- 100k
35
votes
Why do jet engine igniters require huge voltages?
That's nothing special. Car ignition coils also put out 40kV (try grabbing a spark plug wire on your car, that is leaking spark due to insulation breakdown, with your hand while it's running; FUN FUN ...
- 126k
34
votes
Accepted
What is the purpose of the fuel shutoff valve?
It's both a maintenance and safety feature.
You need a way to cut off fuel flow to the engine compartment, either to work on the engine, or because of a fire at the engine, or because you are doing a ...
- 126k
29
votes
How does the fuel pump work in a PA-28 and when should I use it?
The PA-28 Family of aircraft have two fuel pumps, an engine driven mechanical pump that is always pumping (so long as the crank shaft is spinning) and is considered the "main pump". The ...
- 100k
29
votes
Why aren't "fuel polishing" systems removing water & ice from fuel in aircraft, like in cruising yachts?
Sheer volume is the reason.
Aircraft use fuel at an astounding rate.
A Panamax-class container ship is enormous - bigger than the USS Iowa or the Essex class aircraft carriers on display at many major ...
28
votes
Why are fuel tanks located in wings?
added weight increases the structural load applied to the wings
different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-...
- 1,047
27
votes
Accepted
Is excess fuel leaking normal during take off of a B737?
No it is not normal. It can happen if the wing tanks are fully filled, typically for long trips or when the airline is tankering fuel to airports where fuel is more expensive. When cold fuel warms up ...
- 82.9k
26
votes
Accepted
How is fuel managed in the Zero-G A310?
I wrote an email to AirZeroG and asked them:
Other than the interior, are your aircraft modified in any way to handle zero-g flight?
Here is the response that they gave me:
Dear Sir,
...
- 36k
26
votes
What could the fuel pump failure have been that my flight experienced?
The conversation may have been about fuel pumps or fuel transfer valves but the flight attendant was probably told that as a simple explanation - it would not have been the real cause.
Aircraft have ...
- 11.3k
25
votes
Is fuel moved around during flight on a passenger or cargo plane? If so why?
Yes fuel is moved around, and balance is indeed an issue. The A330 has trim tanks in the horizontal stabiliser, and so does the A380. Fuel can be stored there to balance the aircraft - without trim ...
- 61.3k
25
votes
Is fuel moved around during flight on a passenger or cargo plane? If so why?
In 747-100/200 aircraft, takeoff was accomplished tank-to-engine (meaning each engine was fed from it's corresponding main tank). After takeoff the fuel burn schedule called for center tank fuel to be ...
- 39.2k
24
votes
Is there any work on improving fuel tanks so they could store hydrogen?
First, to debunk a myth regarding the Hindenberg, which always gets brought up whenever hydrogen is mentioned. Hydrogen is less safe than liquid fuel, but it is not less safe than natural gas or ...
- 1,271
24
votes
Why didn’t the Captain of Cathay Pacific flight 780 shut down engine 1 and land with a more reasonable speed?
From the incident report section 1.1.4:
a. At 0519 hrs during the descent to a cleared level of FL230, ECAM
messages “ENG 1 CTL SYS FAULT” and “ENG 2 STALL” were annunciated
within a short ...
- 52.9k
23
votes
Accepted
What is the appropriate fuel tank selection to land a 172?
You should check your POH but it may just be that the instructor in question was recently flying a lot of Pipers and it was force of [bad] habit.
This POH for the 172S is in agreement with you.
...
- 100k
22
votes
Accepted
Is there any work on improving fuel tanks so they could store hydrogen?
In gaseous form, the amount of -- the mass of -- hydrogen you could store in the volume of aircraft fuel tanks would be negligible. In order to store enough mass of hydrogen, you'd have to store it ...
- 49.8k
21
votes
Why nitrogen generation system is only present in centre tank only?
The inerting system was added to the A320 as a result of a new FAA regulation in 2008:
On 21 July 2008, FAA required
operators and manufacturers
to incorporate a Flammability
Reduction Means (FRM) or ...
- 54.3k
21
votes
Accepted
Do pilots need a fuel pressure/temperature gauge?
Much depends on your specific aircraft. Some have a need for fuel pressure values, others don't. Likewise fuel temperature readings.
On the 737, there is a light as you describe next to each fuel ...
- 49.8k
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