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Ok..ni satu lag article speku oleh mat salleh
Could missing MH370 flight have been ‘swapped’ mid-air? By Ian Black
Aviation expert and former Malaysian Air Force instructor examines some theories about disappearance
Aircraft expert Ian Black previously worked as a fighter weapons instructor for the Malaysian Air Force, and is author of two aircraft operations manuals, for the McDonnell Douglas F-4 Phantom and the Royal Air Force's Tornado.
He flew the Tornado in the first Gulf War and over Kosovo. He is now an A340 Airbus airliner captain with Virgin Atlantic. He spoke to Yahoo News UK about the mystery of missing MH370.
Could the aircraft have been ‘swapped’ mid-air?
Generally air traffic radars use something called a “Squawk” code – this is 4 digits, say "1234" – that is then used to transmit information to the ground radar of the aircraft’s position and other relevant detail. This is very easily disabled – it is operated with a simple on/off switch. The Boeing 777 has two separate systems for safety in the event of failure.
There is another angle which, I think, might be a possibility: That the MH370 switched codes. If MH370 had a code of, say 4376, then it would be pretty easy to get another aircraft, say a Gulfstream 5 private jet, to fly up behind it and swap codes. The Gulfstream sets its "Squawk' code to the same as MH370's code of 4376, then the B777 takes on the Gulfstream's code, and they then split... It would certainly make it easier for the B777 to continue on undetected.
Why did the Malaysian air force not scramble their fighters?
I actually trained the Malaysian air Force at Kuantan Air Base on the east coast of Malaysia, and they have two MIG-29 fighter aircraft sat on alert 24/7, ready to scramble should an unknown aircraft enter their airspace...why were they not scrambled?
Most countries in this region spend billions of dollars on defense – in particular, air defense – protecting their international airspace and waters.
The Indian Air Force have stated they only turn on their radars on a "need-to" basis – I think that's very unbelievable. I find it almost impossible that a Boeing 777 could be flying over land – whether that's Vietnam, Malaysia, India or further north without anyone seeing it.
Could one pilot have ‘knocked out’ the entire passenger section?
Malaysia Airlines have stated that the co-pilot and captain did not ask to fly together and it was natural rostering that had them crewed on the same flight, so we could probably say that the two were not working as a team.
On all airliners now there is what’s known as a “locked door” policy. That is to say the flight crew are locked in behind a ballistic door, and only allow authorized people in via a video entry system. However, with only two pilots, if one pilot leaves the flight deck to visit the bathroom, he cannot get back in unless the other pilot opens the door. Although there is an emergency code, it is possible to lock the other pilot out. In this scenario you would imagine the other pilot [and passengers] would do everything to gain entry and start using phones, etc. In the cabin there is a medical emergency system, which allows the crew to talk to various medical centers from the cabin.
My only thought on this was the person left in the cabin could have put on his oxygen mask – turned off the passenger oxygen emergency supply and depressurized the aircraft – [and] in a few minutes all the people in the cabin would be unconscious. The pilot could then repressurize the aircraft and remove his mask and fly normally with 250 [passengers] behind him incapacitated – not impossible.
It wouldn’t be difficult for one of the two pilots to either spike the other one's drink as well, or simply kill him behind the locked door – we carry an axe in the flight deck – for emergencies.
Why it’s not likely to have been an accident
Boeing tends to be fairly conservative in their approach to design, sticking to tried-and-tested forms. The B777 has only had three confirmed write-offs since its introduction to service in 1995, and more remarkably, these have all happened on the ground.
So it's quick to see that in 20 years service, no Boeing 777 has blown up in mid-air, had an in-flight fire causing a crash or any other major incident. So what possible causes could lead to a B777 vanishing from the sky?
The B777 has a dual INS/ GPS navigation system that guides the aircraft along airways – their preordained routes – with an accuracy of a few meters. The only time aircraft leave the airway is to avoid bad weather – thunderstorms or clear air turbulence, or occasionally, in the Far East, volcanic ash clouds. As far as I’m aware, there was no bad weather along its intended track, so there would be no reason to divert off course.
Why a bomb or depressurisation is unlikely
If it was a bomb, these are often designed to detonate on a pressure switch, so as the aircraft reaches a certain altitude, the pressure device will detonate, and the bomb will go off. The bomb will normally be in the hold and cause a rapid loss of pressurization, and/or the aircraft to break up. As no wreckage has been found on the original track – within 100 miles of Malaysia, which is where any pressure-activated device would have detonated – I think we can count out a bomb.
Perhaps there was a rapid depressurization? For example, a door [or] cargo door blows open, the aircraft loses pressurization and the oxygen masks, for some reason, fail to come down.
This is unlikely, as the flight crew have a separate system to the passengers and it would need multiple failures for both to go wrong. Also, in the event of losing cabin pressure, the crew would at least have a few seconds, maybe minutes, to put out a mayday call. So again, this would be highly unlikely.
Could the aircraft still navigate with its communications turned off?
For guidance, the Boeing 777 uses a mixture of inertial navigation and GPS. The inertial navigation system is quite old in terms of technology – it dates from the 1970s. But it's very reliable, and will allow aircraft to fly accurately along air routes. Its biggest advantage is that it is an “onboard” independent system, so therefore, unjammable by outsiders. The B777 has three individual systems to cater for failure and or error. They are also used to supply other information to vital flight control systems, so are therefore never turned off.
In addition to [inertial navigation], modern airlines use GPS, the same as in every modern car. Normally, the information is mixed with the INS to give what is known as a “blended” position, i.e., all the information is mixed together to give a very accurate position – accurate to within a few centimeters. The GPS is pretty much unjammable. Airliners normally take information from up to 5 satellites. It can easily be turned off in the flight deck, but as it does not transmit your position and is therefore “covert,” it never is turned off.
The likeliest explanation
In my view suicide looks unlikely – he would have to have been very lucky to kill the other pilot, then fly undetected to a remote spot in the sea and either crash or run out of fuel – it doesn’t add up. Why wouldn’t he have just flown into the Petronas Towers in Kuala Lumpur?
At this stage I have an open mind as to what’s happened – I sadly, however, don’t think it’s an accident. Which leads me to think it must have crash-landed over water – if it’s landed on a remote strip, even camouflaging it would be hard. If it has crashed into the sea, wreckage will be found – perhaps not in the next week, but eventually it will be found.
Ian Black is the author of two Haynes Manuals, the McDonnell Douglas F-4 Phantom Manual and the RAF Tornado Manual |
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Post time 19-3-2014 05:15 PM
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