Flight QZ8501: 5 things that could have gone wrong
PUBLISHED ONDecember 30, 2014 10:35 PM
It is not an exact science.
That is how Australian airline pilot Mark Tonta describes flying into tropical storms.
Mr Tonta, who flies private planes, said radar is used to avoid the storms "to the best of our ability".
"But the equipment we have on board for weather avoidance cannot tell the exact height of storm clouds. Only experience helps you to form a plan of track change and level change," he said.
Although the reasons for AirAsia Flight QZ8501 going missing yesterday are still unclear, Indonesian authorities said the plane had been flying at 32,000 feet and the pilot had asked to fly at 38,000 feet to avoid clouds.
Mr Tonta felt that to fly into a fully active large storm that is near 52,000 feet could be "from poor decisions made for a number of reasons, even technical problems such as radar failure".
BREAK UP
"Entry into this sort of storm could cause the aircraft to break up in flight for sure," he said, adding that a lack of distress call could also be because of the extreme conditions on board such as violent turbulence.
A former pilot, who declined to be named, said he would usually try not to fly into a storm if possible.
"But if I have to then, I would make sure everyone is strapped in before selecting the recommended penetration speed to do so," he said.
He recalled a flight from Kuala Lumpur to Singapore which encountered a storm that caused the whole aircraft to shake violently.
"I had the autopilot on, but because of the violent vibration, I was guarding it closely and ready to take over should it trip ... Since that experience, I have learnt to respect the force of nature," he recounted.
Mr Tonta said pilots should never make a choice if there is no Plan B.
"Sometimes it's hard to see on radar past the storm just in front ... so you always keep an option that is safe. Maybe you burn more fuel or have to divert to another airport but always have a plan B," he said.
1. HIGH SPEED OR LOW SPEED STALL
Sufficient airspeed must be maintained in flight to produce enough lift to support the airplane. At a specific angle, air going over a wing will separate from the wing, causing the wing to lose its lift (stall).
2. AIRCRAFT ICING
If present on pitot static tubes, which are used to measure pressure, this can cause instrument errors.
3. PENETRATION SPEED
The faster the plane strikes an up draft or down draft, the greater the shock.
4. LIGHTNING STRIKE
This can cause electrical surge or damage to the instruments. For instance, a lightning strike can turn coloured computers and flight instruments to monochrome.
5. HUMAN ERROR
When the pilot's decision may not be the right one.
Timeline of flight QZ8501
6.36am (Singapore time; 5.36am Surabaya time)
AirAsia Indonesia Flight QZ8501 takes off from Surabaya's Juanda International Airport. It was scheduled to take off at 6.20am Singapore time. It goes to 32,000 feet and is meant to take the expected flight path M635.
7.12am (Singapore time)
In the plane's last contact with air traffic control, the pilot requests to divert from the flight path to avoid poor weather. It also requests to climb to 38,000 feet. Air traffic control agrees.
7.16am (Singapore time)
Indonesian air traffic control is still able to detect the plane on radar.
7.17am (Singapore time)
This is when the plane loses contact with air traffic control, said Mr Djoko Murjatmodjo, the director-general of aviation at Indonesia's ministry of transportation.
8.08am (Singapore time)
Incerfa - also known as the Uncertainty Phase, when the time of last contact between an aircraft and air traffic control exceeds 30 minutes - is activated.
8.28am (Singapore time)
The next phase, Alerfa, also known as Alert Phase, is activated.
8.55am (Singapore time)
The aircraft is considered to be in Detresfa, or Distress Phase, and is officially considered missing. During this phase, search operations are activated.
1.48pm (Singapore time)
Indonesia news portal Detik.com reports Indonesian Transport Minister Ignasius Jonan as saying that search operations are being focused on an area off East Belitung. Unconfirmed reports of the plane crashing in the area emerge.
3.58pm (Singapore time)
AirAsia boss Tony Fernandes tweets that he is flying to Surabaya, where the passengers' next-of-kin have gathered at Juanda Airport. In Singapore, next-of-kin are briefed in a holding room at Changi Airport Terminal 2.
4.29pm (Singapore time)
The Civil Aviation Authority of Singapore says Indonesia has accepted Singapore's offer to assist in search-and-rescue operations. Singapore launches one C-130 aircraft for the search.
6.30pm (Singapore time)
The C-130 reaches the search area.
7.25pm (Singapore time)
Indonesia announces it is halting search-and-rescue operations for the night due to poor light and weather conditions. Operations are expected to resume early today. The Singapore air force will send two C-130s for the search today.
This article was first published on December 29, 2014.
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