107
votes
Accepted
How did the 9/11 hijackers find their way to New York City?
Several of the hijackers, including Mohamed Atta, held at least private pilot certificates and had undergone ATP level jet training in DC9 and 737 full motion simulators in December of 2000. Atta ...
- 70.4k
95
votes
Accepted
Why do aircraft models end their life as freighters?
Passenger operations are overwhelmingly scheduled whereas cargo is on demand and thus less easy to plan. The upside: A cargo plane crew will fly quite diverse routes. The downside: Capacity ...
- 226k
95
votes
Accepted
Why is the lower deck of the Airbus A380 curved like a single deck airplane?
The cabin interior is curved to accommodate, among other things, the brackets holding the upper deck floor beams.
These brackets are a structural feature that transfers the weight of the upper deck ...
- 19.3k
83
votes
Accepted
Why do airliners have to park so accurately?
This is to ensure that there is space for all equipment around the aircraft. It's not critical to the centimeter, but if it's off by a meter or more there may be problems. For example, the tail may ...
- 4,526
77
votes
Accepted
How hazardous is it if an engine cowl falls off?
I work in aero engine safety but not for the company that manufactured the engine in the event you mention.
Parts falling off engines is Not Good. We worry about them hitting people below the ...
- 835
75
votes
Accepted
Can a human get sucked into a jet engine?
Yes. Human beings can get sucked into jet engines if they are close enough- this has happened multiple times in a number of aircraft ranging from A319 to A6E intruder.
However, it happens only in ...
- 99.6k
73
votes
Accepted
Has any passenger airliner ever offered forward-facing windows?
We could start with the Tupolev ANT-20 with its rather daring forward-facing passenger gallery. [edit - the prime seat right at the front in the gallery was for the navigator and his equipment.]
...
- 10.2k
67
votes
Accepted
What prevents a commercial jet from electronically "resetting" the way a computer sometimes does?
I'm a programmer and private pilot, so maybe I can help dispel some of those fears.
The computers that run a commercial airplane are conceptually much simpler than the one that runs your phone. This ...
- 12.8k
62
votes
Accepted
Why don't airliners use in-air refueling systems?
Fuel Quantity Unlike smaller fighter jets, you would need to offload a substantial quantity of fuel. For a B777, you're looking in the range of 60 tonnes of fuel for half a tank. The boom of a KC-135 (...
- 33.1k
62
votes
Accepted
Has any airliner ever collided with a glider?
Yes. (I found this by Aaron Holmes's hint that he searched only English sources.)
On 1999 Feb 12 at 3:40 pm, a Grob G103 sailplane F-CGXB (possibly "in wave flight") collided with an Airbus ...
- 9,907
58
votes
How did the 9/11 hijackers find their way to New York City?
All of the hijacked flights were going in different directions and had to be piloted to a different destination. The hijacker pilots had different degrees of success in doing this. The flight paths ...
- 13.1k
53
votes
Can a human get sucked into a jet engine?
what is the minimum or maximum weight that these engines can suck?
Quite a lot, considering they can ingest ramp equipment...
This is a JAL 747 ingesting a baggage container.
Delta L-1011 doing the ...
- 1,581
53
votes
Accepted
Can airliners be considered as GA?
GA refers to why you fly your plane, not what kind of plane it is. For example, John Travolta has (had?) his own personal Boeing 707, which is the first generation of jet airliner from Boeing. When he ...
- 9,122
52
votes
Accepted
Can commercial airliners fly over central Antarctica during winter?
Surface air temperatures aren't really going to be relevant for an airliner. The temperature of the troposphere doesn't vary that much. In fact, the troposphere is warmer at the poles (from Wikipedia ...
- 9,122
50
votes
Accepted
What is this line found above the door on many aircraft?
These are rain gutters.
They are designed to catch rain that runs off the upper surface of the aircraft fuselage and channel it away from the open aircraft door so that the water does not enter the ...
- 16.5k
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 ...
- 70.8k
48
votes
Is it possible for an airliner to safely fly with doors open?
The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a modified 747 that has an 5.5 m x 4.1 m door that is opened during flight for the installed in infrared telescope. But the door is ...
- 581
47
votes
Why do airliners have to park so accurately?
I worked for 3 years as a ramp agent and there are two reasons:
Jet bridges and safety.
Jet bridges have plenty of leeway, but not a lot. This gets worse in winter because those things hardly move ...
- 821
47
votes
Why then don't aircraft fly even higher, for even greater efficiency?
Some do (or have in the past) but very high altitudes present their own issues. Historically the Concorde cruised anywhere from FL550 to FL600 and was actually allowed to climb and descend at its ...
- 99.2k
47
votes
Is 'bouncing' an airliner on landing in high winds a deliberate technique, or something always unexpected?
Bouncing a landing is neither intentional nor desirable. There are several reasons why a student pilot might bounce, but for a professional pilot, it's most likely related to wind gusts, which are a ...
- 27.4k
47
votes
Why is waste water from lavatory sinks dumped outside in mid-flight?
“Grey” water from the lavatory and galley sinks is dumped overboard through electrically heated drain masts.
It is much cheaper and simpler to drain it overboard rather than store it. Dumping it also ...
- 36.8k
45
votes
Accepted
Is gravity less on an airliner at cruise altitude?
There is less gravitational force, but by how much? An insignificant amount.
The gravitational force of attraction between two objects is given by,
$\displaystyle F_{\mathrm g} = \frac{G m_{1} m_{2}}{...
- 99.6k
45
votes
Accepted
Is there any emergency situation in which jet engines would not be shut down before passenger evacuation of a transport aircraft?
It is possible for the engine to not respond to shutdown sequence, so you'd have to get the passengers off before dealing with the rogue engine.
In the Qantas Flight 32 one engine had an un-...
- 3,549
45
votes
How much of an improvement would a 1% weight decrease on an airplane be to the industry?
There is an easy way to get an idea of what magnitude the savings are: The Breguet equation can answer this. You first calculate a reference aircraft and then start all over with one that weighs 1% ...
- 226k
45
votes
Is it illegal to partially block the aisle on a passenger airliner?
Cargo cannot block the aisle -
FAR Part 121.285, governing U.S. Air Carrier Operations, states in pertinent part:
FAR 121.285-
(emphasis mine)
(c) Cargo may be carried aft of a bulkhead or divider in ...
- 27.8k
45
votes
When does an airliner switch from using the tiller to the rudder?
I flew for two 747 carriers that never bought new aircraft, and thus this answer applies to 747-100/200 aircraft as originally manufactured for a number of different airlines.
The tiller is active ...
- 39k
44
votes
Why are safety demonstrations done while taxiing?
Many passengers don't reach the gate until seconds before the gate closes for a variety of reasons. They won't get the pre-boarding briefing.
Taxiing is the only time before takeoff where the crew ...
- 27.3k
Only top scored, non community-wiki answers of a minimum length are eligible