Singapore (AFP) - Nearly three
days after it disappeared while en route from Kuala Lumpur to Beijing,
mystery still shrouds the fate of Malaysia Airlines flight MH370 and the
239 people on board.
No debris from
the Boeing 777-200ER has been recovered despite an international search
involving the navies and air forces of several Asian nations as well as
the United States.
Following are some questions surrounding the disappearance and the search, and answers by industry experts who spoke to AFP:
Q: Could the plane have disintegrated in mid-air?
The
failure of the plane's pilots to send a distress signal has given rise
to speculation there was a sudden catastrophe -- possibly caused by a
mechanical failure or an explosion.
The
lack of wreckage recovered so far also suggests a high-altitude
disaster which spread debris across an area too wide to be easily
detected.
"If it had been an
impact at sea level of the whole craft, chances are more debris will be
found immediately," said Chris de Lavigne, an expert on aerospace and
defence issues at business consultancy Frost & Sullivan.
Sudden,
accidental structural failures are considered extremely unlikely in
today's passenger aircraft. This is especially so with the Boeing
777-200, which has one of the best safety records of any jet.
Authorities said the plane was at cruising altitude, 35,000 feet (11 kilometres) above sea level, when it last made contact.
"It's
the safest point in the flight," de Lavigne said. "It's an extremely
safe aircraft with very, very few incidents in its history. This is just
overly puzzling."
Q. Have there been other plane mysteries like this?
Air
France flight 447 crashed into the Atlantic Ocean in June 2009 while on
a flight from Rio de Janeiro to Paris, killing 216 passengers and 12
crew. Debris was not found for days and it took years to locate the
wreckage. Investigators eventually concluded that both technical and
human error were to blame for the tragedy.
Adam
Air flight 574 with 102 people on board disappeared from radar in
January 2007, also at its cruise phase during a domestic flight in
Indonesia. Debris was found nine days later after an extensive search
and it took months to recover the plane's black box.
Indonesian authorities said the pilots lost control after becoming preoccupied with malfunctioning navigational equipment.
Q: What are the theories on what happened to MH370?
"One possibility is a mid-air explosion," said Gerry Soejatman, an Indonesia-based independent aviation analyst.
"The
other is when there is a simple problem and then the crew tries to
diagnose it, gets caught up in it and then they don't realise what's
happening and the plane crashes. That's what happened with the Air
France case. At the moment, until we find anything, it has to be one of
these two scenarios."
De Lavigne said that at this stage, with so little information, all possibilities must be considered.
"It's either a serious mechanical failure or something a little bit more sinister," he said.
"It's
pretty surprising that there was no SOS call from the plane and it just
disappeared. It would lead to the conclusion that something fast and
drastic happened."
Malaysian authorities have launched a terror
investigation, but are refusing to rule anything out, including a
possible hijacking.
Q: Why is it so hard to find evidence?
The region being searched,
including the Gulf of Thailand and the South China Sea, are busy
shipping lanes with large amounts of flotsam that will complicate the
search for any wreckage.
"When
they see something, it is not blatantly obvious that it is a wing or
tail. They have to go and examine what it is, it takes time," Soejatman
said.
Q: Why have authorities not picked up any signals?
Aircraft
have an Emergency Locator Transmitter (ELT) which is designed mainly
for when the plane crashes on land and pilots are still trying to
control it. In the event of a major crash, it may not work.
"Basically
what this beacon does is simply say 'I've been activated, find me!'"
Soejatman said. "It is not fool-proof but it is the best thing that we
have at the moment."
The plane
also has a "black box" consisting of the cockpit voice recorder and the
flight data recorder. If immersed in water they should activate a
"pinger" that can draw investigators to the location. However, the sound
cannot be heard over long distances.
"You
need a ship equipped with a listening sonar to pick up the signal
within the area," Soejatman said, cautioning however that the shallow
waters of the MH370 search site could create interference.
The
missing Boeing 777-200ER was also equipped with ACARS (Aircraft
Communications Addressing and Reporting System), a system which sends
short messages to ground controllers -- either automatically or manually
depending on the airline.
"If
Malaysia Airlines does have these messages, that would be very useful"
to determine events before it lost contact, Soejatman said.
Malaysia
Airlines' chief executive Ahmad Jauhari Yahya told reporters at a press
conference late Monday that the missing aircraft was equipped with
ACARS, but did not provide any further details.
An
airline representative later confirmed: "The aircraft has got the ACARS
system which transmits automatically. There were no distress calls. No
information was relayed."
Q: Is security at Kuala Lumpur International Airport questionable?
Revelations
that at least two people aboard the plane were using stolen European
passports have heightened fears about a security breach.
Rohan
Gunaratna, a terrorism expert at Singapore's Nanyang Technological
University, said the passport issue could indicate a "glaring flaw" in
the airport's immigration clearance.
He noted that Interpol maintains a database of stolen passports that should have raised alarms at the immigration counter.
"There are two categories of people who use these (stolen passports) -- criminals and terrorists," he said.