Malenaspecial » 13 мар 2014, 12:35
‘A 777 needs a runway that is a good 2,000m (2,180 yards) long,’ says Robin Durie, an experienced commercial pilot.
After a plane has crashed, the black box transmits a homing beacon, but the range is only 2,000 or 3,000 yards, and even less if it is deep underwater.
Are there areas of the world where a plane can just ‘slip off the radar’?
Plenty. Tracts of Africa, much of the interior of Russia, jungles in Malaysia, for example.
Modern airliners use transponders, which transmit a unique four-digit code that is identified with the flight. It is these codes that are picked up by air traffic controllers and used to locate the aircraft.
If the transponder stops transmitting – either because it is turned off or as the result of a sudden, catastrophic incident – then over many parts of the globe, the plane would be invisible to air traffic controllers.
Why was no distress signal sent?
‘If you have some form of emergency, then the first thing the pilot does is to change the transponder code,’ says Mr Durie. ‘If you change your code to 7500, that means you have been hijacked.
‘Back at Air Traffic Control, a big red box appears around your flight, and people take notice very quickly.’
In the event of a serious malfunction, the code changes to 7600, and in a Mayday situation, to 7700.
Changing the code is as quick as entering your PIN on a cash machine.
‘The fact that the transponder code didn’t change suggests to me that whatever happened, happened really quickly,’ says Mr Durie. ‘This might mean an explosion.’
A pilot on another aircraft claims to have made contact with MH370 shortly before it went missing – but all he heard was mumbling. What could this mean?
'All pilots have frequencies that we use to chat on,’ says Mr Durie. ‘Often this is company traffic, when crew from the same carrier are simply talking to each other.
‘Technically, it’s not legal, but the practice is widespread and many pilots tune into the easy-to-remember VHF band of 123.45.’
If another pilot heard some mumbling, it is possible that it was chat coming from another pilot on the same frequency. However, it could have been a crew member from MH370.
‘The mumbling suggests to me that the pilot was passing out from a lack of oxygen,’ says Mr Durie, ‘which could mean that the aircraft had suffered an explosive decompression, such as a window popping out, or a small hole appearing in the fuselage.’
Would it be possible for a deranged or psychotic passenger to seize control and cause a disaster?
The door to the cockpit is locked, and can be opened only from the inside. However, large airliners carry an axe in a secret location in one of the galleys.
A fanatic who found the axe could break into the cockpit, but it is unlikely the axe could be found without the knowledge of the cabin crew.
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