The specter of a modern long range jumbo jet suddenly falling from the sky with no distress call suggests horrific causes. Two hundred and thirty-nine souls have apparently lost their lives as Malaysia Airlines Flight 370 suddenly disappeared from radar and contact, and an oil slick has been spotted in the South China Sea.  

Most (153) of the passengers on board were Chinese, but there were also “five Indians, four French, three US citizens, two passengers each from New Zealand, Ukraine, and Canada, and one each from Russia, Italy, the Netherlands and Austria.”

Relatives waiting in Beijing are understandably distraught:

Relatives of the passengers were directed by the Chinese police to the Lido Hotel in Beijing where they waited for news in a large conference room.

Angry relatives accused the airline of keeping them in the dark and failing to provide updates as they were received.

About 20 people stormed out of the room at one point, enraged they had been given no information.

"There's no one from the company here, we can't find a single person. They've just shut us in this room and told us to wait," said one middle-aged man, who declined to give his name.

"We want someone to show their face. They haven't even given us the passenger list," he said.

Another relative, trying to evade a throng of reporters, muttered: "They're treating us worse than dogs."

There are only a few possible causes of the sudden disappearance of a modern airliner. None are comforting:

1. Some kind of equipment malfunction that completely preoccupied the crew and led to a sudden crash. This almost never happens, but did occur in the case of Air France 447 lost in the South Atlantic on the way from Rio de Janeiro to Paris, when ice crystals apparently led to the auto pilot shutting off, and crew mistakes coping with the situation caused the crash. In the early days of jet airliners, Comet aircraft were lost when the cabin blew apart under pressure, but this is highly unlikely given the advances in materials. Still, Aloha Airlines Flight 243 did suffer an explosive decompression in 1988 on Boeing 737, and was at low enough altitude to survive.
2. Pilot suicide cannot be ruled out. An Egypt Air Flight 990, a Boeing 767, crashed into The Atlantic Ocean when its first officer likely deliberately crashed, according to the US NTSB. Egyptian civil air authorities disputed this conclusion, blaming mechanical malfunctions, but the NTSB countered that the flight data recorder showed aircraft movements that could not be explained by mechanical malfunctions.  
3. Terrorism, including hijacking, a bomb or a ground to air missile, cannot be ruled out. Malaysia Airlines (then known as Malaysian Airlines System – MAS) Flight 653 was lost in 1977 when it crashed, apparently having been hijacked after take-off, with the loss of all hundred people on board the Boeing 737. It must be noted that China sufferedd a bloody terror attack from jihadists, killing 29 people,  at the Kunming Railway station last Saturday.

None of these possibilities is comforting.

Malaysia Airlines is regarded as having a good safety record, but has suffered large losses over the years, though it is backed up by the oil-rich Malaysian government, and is still ordering new aircraft, despite its losses.