164
votes
Why do airplanes use MAYDAY when in danger but ships send SOS?
The difference here isn't between ships and aircraft: it's between Morse code and voice.
The SOS signal is only for Morse code. It's short, easy to send, and easy to recognise. But it's not as ...
- 12.6k
82
votes
How miraculous was the miracle on the Hudson?
This would be an extremely difficult question to answer without being opinionated, but I'll give a try. As part of the investigation, the NTSB, along with other agencies carried out a number of tests ...
- 98.8k
74
votes
Accepted
What are the advantages of squawking 7700?
If you make a radio call, unless you are on 121.5 (or 243 military), then only the station you are talking to will initially know about the emergency. Initial calls should always be with the unit you ...
- 30.9k
63
votes
Accepted
Why not just drop an engine on fire?
The current position of regulators like the FAA is that dropping things off of airplanes in flight is a bad thing. Dropping extremely large and heavy things like engines would be extremely bad. This ...
- 69.9k
63
votes
Why are there many pilots who don't say "mayday, mayday, mayday" to declare an emergency?
I'm a controller, not a pilot, so I can only speak from my own perspective.
What we are taught in ATC school is that many pilots are reluctant to use the word mayday because they feel it might ...
- 35.2k
61
votes
If a typical passenger plane had total failure of all engines mid-flight, is it possible for passengers to survive?
Air Transat Flight 236 experienced a complete power loss over the Atlantic Ocean in 2001. Yes, all passengers and crew survived after the aircraft glided 75 miles to a runway on the Azores islands.
...
- 802
61
votes
Accepted
Why is the time of useful consciousness only seconds at high altitudes, when I can hold my breath much longer at ground level?
When you are breathing, oxygen ($\mathrm{O}_2$) and carbon dioxide ($\mathrm{CO}_2$) are exchanged between the alveoli in your lungs and the environment. This gas exchange is based on diffusion, which ...
- 47.6k
58
votes
Accepted
What prevents a passenger from opening the emergency door on his own will, mid-flight?
At cruising altitude there is between 4 and 8 tons of pressure acting on the inside of the door. There aren't too many passengers capable of exerting that much force on the handle (and even fewer ...
- 14.6k
56
votes
Why did the Swiss International Air LX40 (a 777-300ER) emergency land at Iqaluit airport?
Given that the 777-300ER could have easily flown the remainder to LA with one engine -- which means it could have easily diverted to a nearby larger airport -- why didn't it?
Standard operating ...
- 54.6k
51
votes
Accepted
What level of damage to an aircraft is acceptable to let it depart?
Aircraft Maintenance Engineer here.
To evaluate if an aircraft is safe to fly we use three main reference documents:
1. MEL (minimum equipment list).
This document contains the list of elements ...
- 1,132
50
votes
Accepted
Why are pilots deemed unfit to fly after emergency ejection?
Ejection Seats are not a free ticket out. They are incredibly violent and rough on your body. This newspaper article has a more chilling quote from an interview:
About one in three will get a ...
- 32.8k
50
votes
Accepted
What is the procedure when an aircraft with an emergency can't land due to a blocked runway?
What's the procedure? The procedure is, be creative to save as many lives as possible!
Really. The procedure is to determine a course of action which will likely result in the best outcome for ...
- 39.3k
50
votes
Accepted
Why does ATC ask a crew who has declared an emergency if their aircraft will be overweight when landing?
If an aircraft encounters a serious problem quite soon after departure that forces it to land immediately, the aircraft may be above its certified maximum landing weight. This is because there is ...
- 35.2k
49
votes
Accepted
Do jet aircraft have an emergency propeller?
I think you might have heard about the Ram Air Turbine, which is deployed in case of some aircraft in case of loss of main electrical power supply. From A320 Systems briefing:
In case of total loss ...
- 98.8k
47
votes
Accepted
Why evacuate upwind?
There are two problems linked to the wind after accidents:
Inflating the slides.
Running away from the aircraft when on the ground
@DavidRicherby listed the reasons related to running away upwind to ...
- 68k
47
votes
Accepted
How should passengers report SOS signal sightings?
There is a procedure, at least for the aircraft crew.
It is appropriate for a flight crew to transmit a "pan pan" or even a "mayday relay" so a passenger should immediately inform the senior cabin ...
- 30.9k
47
votes
Is it practical to intentionally stall an aircraft to execute a fast, controlled descent?
It isn't practical for a number of reasons:
Intentional stalls are inherently dangerous. Stall-spin accidents are a major cause of accidents, stall recognition and recovery are taught specifically to ...
- 50.6k
46
votes
Accepted
Do you have to explain what your emergency is?
The order is "Aviate, Navigate, Communicate".
As a pilot, your first responsibility is to keep the plane flying. After that it is to avoid hitting something or to avoid getting lost. After ...
- 35.2k
46
votes
Accepted
After declaring an emergency can a pilot legally resume normal navigation without landing?
You haven't missed anything. There's no regulation saying that if you declare an emergency that you must land, if a situation resolves itself or the actions taken mean that a flight is no longer in ...
- 50.6k
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-...
- 3,538
45
votes
What is typical ATC procedure when a non-pilot calls from a commercial flight for help?
There is absolutely nothing "typical" about such a situation, which is also why - as is the case for most abnormal situations and emergencies - there are no detailed and specific standard ...
- 35.2k
44
votes
Accepted
Can a plane fly without the vertical stabilizer?
The plane will probably crash.
The vertical stabilizer provides stability in yaw to conventional aircraft. Aircraft such as the B-2 manage to provide stability through computer control, and aircraft ...
- 69.9k
44
votes
Accepted
Pilot passed out in a small GA plane. What can a passenger do?
Best case scenario: You're straight and level, on frequency with some form of human being, there's no immediate danger and you have the know-how to transmit. In that case, that human will provide you ...
- 26.4k
44
votes
Accepted
Why can't you ditch your aircraft in the sea?
The writer was dramatizing things a bit maybe, it's possible to ditch a jet fighter and survive, however your chances are much better ejecting.
Ditching is an option for any aircraft, with some ...
- 50.6k
42
votes
Accepted
Does air traffic control identify a distress situation when an aircraft flies triangles in the sky?
To my surprise, this does exist, at least in the UK. According to the Manual of Air Traffic Services:
7 Emergency Triangle Procedure
7.1 Pilots lost or uncertain of position and experiencing ...
- 70.6k
42
votes
Why can't an Airbus A330 dump fuel in an emergency?
To supplement Jimmy's answer, if they had to land right away, they could have; it just would've resulted in an overweight landing being recorded, and which on most airliners triggers a special ...
- 110k
41
votes
Why are cockpit alarms still so distracting and unable to be silenced?
A stall condition needs to be handled now, and once it's handled, the alarm will go away. What you don't want to happen is you are in an approaching stall condition, the pilot hits a "silence&...
- 35.2k
40
votes
Why evacuate upwind?
If there is a fire, any smoke and flames will blow downwind. If there is a fuel leak, the fuel vapours will be blown downwind, risking a fire or explosion there and potentially making it hard to ...
- 11.8k
39
votes
Accepted
Can civilian aircraft fly through or land in restricted airspace in an emergency?
FAR 91.3 states that any pilot in command may deviate from any regulation or rules to the extent needed to deal with the emergency. That includes entering restricted or prohibited airspace.
In the ...
- 66.8k
38
votes
What are the advantages of squawking 7700?
Aircraft squawking 7700 are getting a special indication (e.g highlighted, distinct colour, boxed) on Air Traffic Control (ATC) displays. This helps to identify the emergency aircraft not only to the ...
- 75.4k
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