It took two years to find the main wreckage of an Air France jet that plunged into the Atlantic Ocean in 2009. Closer to the area between Malaysia and Vietnam where Saturday's flight vanished, it took a week for debris from an Indonesian jet to be spotted in 2007. Today, the mostly intact fuselage still sits on the bottom of the ocean.
"The world is a big place," said Michael Smart, professor of aerospace engineering at the University of Queensland in Australia. "If it happens to come down in the middle of the ocean and it's not near a shipping lane or something, who knows how long it could take them to find?"
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Amid the confusion, officials involved in the search say the Malaysian jet may have made a U-turn, adding one more level of uncertainty to the effort to find it. They even suggest that the plane could be hundreds of kilometers from where it was last detected.
Aviation experts say the plane will be found - eventually. Since the start of the jet age in 1958, only a handful of jets have gone missing and not been found.
Relatives of victims from the missing Malaysian jet complete paperwork for their Chinese passports to be ready to travel to the crash site in Beijing. (AFP photo)
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"I'm absolutely confident that we will find this airplane," Capt. John M. Cox, who spent 25 years flying for US Airways and is now CEO of Safety Operating Systems, said Monday. The modern pace of communications, where GPS features in our cars and smartphones tell us our location at any given moment, has set unreal expectations. "This is not the first time we have had to wait a few days to find the wreckage."
Based on what he's heard, Cox believes it's increasingly clear that the plane somehow veered from its normal flight path. He said that after the plane disappeared from radar, it must have been "intact and flew for some period of time. Beyond that, it's all speculation." If it had exploded midair along its normal flight path, "we would have found it by now."
China's largest patrol vessel Haixun 31 (C) is seen at a port before leaving for search and rescue operations for the missing Malaysia Airlines jet in Hainan province. (Reuters photo)
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Malaysian civil aviation chief Azharuddin Abdul Rahman, whose agency is leading a multinational effort to find the Boeing 777, said more than 1,000 people and at least 34 planes and 40 ships were searching a radius of 100 nautical miles (115 miles; 185 kilometers) around the last known location of Flight MH370. No signal has been detected since early Saturday morning, when the plane was at its cruising altitude and showed no sign of trouble.
Azharuddin said the search includes northern parts of the Malacca Strait, on the opposite side of the Malay Peninsula and far west of the plane's last known location. Azharuddin would not explain why crews were searching there, saying, "There are some things that I can tell you and some things that I can't."
Some aviation experts are already calling for airlines to update their cockpit technology to provide a constant stream of data - via satellites - back to the ground. Information about key system operations is already recorded on the flight data and voice recorders - the so-called black boxes - but as this crash shows is not immediately available. Such satellite uplinks would be costly and the benefit is debated.
A Chinese relative of passengers aboard a missing Malaysia Airlines plane cries while leaving a hotel room for relatives or friends of passengers aboard the missing airplane, in Beijing. (AP photo)
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Just about every major jet to disappear in the modern era has eventually been found. The rare exceptions didn't involve passengers.
In September 1990, a Boeing 727 owned by Faucett Airlines of Peru was ditched into the North Atlantic after running out of fuel on its way to Miami. The accident was attributed to poor pilot planning and the wreck was never recovered.
More mysterious was the disappearance of another 727 in Africa. It was being used to transport diesel fuel to diamond mines. The owners had numerous financial problems and one day, just before sunset, the plane took off without clearance and with its transponder turned off. It is believed to have crashed in the Atlantic Ocean. One theory, never proven, is that it was stolen so the owner could collect insurance.
People prepare to release a sky lantern during a candlelight vigil for passengers aboard a missing Malaysia Airlines plane. AP
"I can't think of a water crash in the jet age that hasn't been solved ," said Scott Hamilton, managing director of aviation consultancy Leeham Co.
The Malaysia Airlines jet had been headed from Kuala Lumpur to Beijing. The 239 people aboard were mostly from China. In Beijing, passengers' relatives have complained that the airline has not been forthcoming with information, and that they've had to rely on news reports.
Some of those reports, however, have led to dead ends. Those false alarms appeared to leave searchers with little to go on.
The flight "was very high up in the air early in the morning, when it was still dark," Azharuddin said. "We have no witnesses on the ground and nobody on the plane can be contacted. The area is over the sea, so it's not as easy as that. There are a lot of constraints."
Clouds hover outside the window of a Vietnam Air Force search and rescue aircraft An-26 on a mission to find the missing Malaysia Airlines flight MH370, off Vietnam's Tho Chu island March 10, 2014. REUTERS
Whether the plane broke up in midair or crashed into the water, there would be some debris.
If the plane broke up "for some aerodynamic reason, like the wing fell off or there was a depressurization, there'd be big chunks of wing and fuselage all over the place. So it'd be very unlikely that it would just be destroyed and turned to dust," said Smart, the aerospace engineering professor.
He added that much of the wreckage may be at the bottom of the sea, which is 50 to 60 meters (165 to 195 feet) deep in the area where the plane was last detected.
The size of the debris field will be one of the first indicators of what happened, aviation experts say. A large, widespread field would signal the plane likely broke apart at a high elevation, perhaps because of a bomb or a massive airframe failure. A smaller field would indicate the plane probably fell intact, breaking up upon impact with the water.
Discovering the debris can take days.
A helicopter prepares to land onboard the China Maritime Safety Administration (MSA) ship Haixun-31 during a brief stop in Sanya in southern China's Hainan province. AP
A week after an Adam Air flight carrying 102 people vanished over Indonesian waters on Jan. 1, 2007, an Indonesian navy ship detected metal on the ocean floor. But it would take another two weeks for the U.S. Navy to pick up signals from the flight data and cockpit recorders, and seven months for the boxes to be recovered. The fuselage remains on the ocean floor, and Adam Air is now defunct.
The Malaysian Airlines jet could be less of a challenge than the Adam Air crash in one respect: It was last tracked over much shallower water.
But for now, the mystery is overwhelming.
"It's hard to imagine what could have caused it with these modern planes," Smart said.
A woman holds a candle as she takes part in a candlelight vigil held by Malaysian ethnic Chinese for the passengers of Malaysia Airlines MH370. REUTERS
Here are main the similarities and differences to AF447 case:
- Still missing three days into the search. The Air France plane was located nearly two years after its disappearance. Only a few pieces of the tail were retrieved a week after the crash.
- Cruising. Airliner was above sea and at cruising altitude.
- Number of passengers. MH370 had 239 and AF447 had 228, including 12 crew in both cases.
- Safety. Both the Malaysian Airlines Boeing 777-200 and Air France Airbus A330 have outstanding safety records.
- No mayday call. Aviation experts say that is not surprising, arguing that in the event of a sudden technical problem the crew's priority is to find a solution.
- Repairs. Both jets suffered minor damage on the ground and underwent repairs. In the case of flight AF447, it was established there was no correlation with the crash.
- ACARS. The Airbus had sent 24 automatic messages listing technical "events" in four minutes through the Aircraft Communications Addressing and Reporting System (ACARS). The Malaysian jet was equipped with ACARS but the airline has not yet said whether any messages had been received.
- Cruise phase. Both planes were cruising when they disappeared but in the case of flight MH370, the cruise phase had just begun, meaning the captain was likely in command of the flight deck. On the Airbus, the captain was resting and only returned to the cockpit moments before the jet went down.
- Weather. Conditions appeared good on the Malaysian aircraft's path while the Air France flight encountered major turbulence.
- Radar. Flight MH370 went missing in a busy area for air traffic, likely to be well monitored as it is close to several countries. The Rio-Paris flight went down over the Atlantic, outside of radar coverage.
- Recovery. The Air France jet crashed further away from the coast and into very deep waters, a complicating factor for the investigation.
- Relevant authorities. The AF447 crashed in international waters, allowing for French investigators to take the lead. Since the MH370 has yet to be located, it is unclear whether the Malaysians, the Vietnamese or other authorities should be in charge.
(AFP and AP inputs)