Searching for the plane truth -- amid speculation

It's been more than 12 days since Malaysia Airlines Flight 370 went missing from radar screens, and hard facts about its fate remain in short supply.

To fill the vacuum, experts and amateurs have been conjuring and sharing theories about what may have caused the commercial airliner carrying 227 passengers and 12 crew members to seemingly disappear.

Here are some of the leading theories:

Pilot Chris Goodfellow, in a posting published by Wired Magazine, suggests a simple scenario in which a wheel of the heavily loaded plane overheated as it lumbered toward takeoff from Kuala Lumpur, Malaysia.

"Yes, this happens with underinflated tires," he wrote, adding that the tire may have smoldered initially and not caught fire until some time into the flight.

Once he became aware of the fire, pilot Zaharie Ahmad Shah would have turned left toward the closest, safest airport -- Langkawi International Airport, a 13,000-foot airstrip that has an approach over water, he said.

"The captain did not turn back to Kuala Lumpur because he knew he had 8,000-foot ridges to cross," Goodfellow wrote. "He knew the terrain was friendlier toward Langkawi, which was also closer."

The loss of the jet's transponders and communications could be expected in a fire, and a pilot's first response would be to pull the main buses -- conductors carrying a computer system's data and control signals -- "and restore circuits one by one until you have isolated the bad one," he said.

If the buses were pulled, "the plane would go silent. It probably was a serious event and the flight crew was occupied with controlling the plane and trying to fight the fire. Aviate, navigate, and lastly, communicate is the mantra in such situations."

He said radar reports that the plane ascended to 45,000 feet were unreliable. And, even if true, they are not necessarily damning. The pilot might have been seeking to quell the fire by going to an altitude with less oxygen, he said.

A reported rapid descent could have resulted from a stall at such a height, above the plane's limit, followed by a recovery at 25,000 feet. "The pilot may even have been diving to extinguish flames," he said. "But going to 45,000 feet in a hijack scenario doesn't make any good sense to me."

Goodfellow speculated that smoke may have incapacitated the pilots and crew, leaving the plane to continue on autopilot until it ran out of fuel or the fire caused it to crash. "You will find it along that route -- looking elsewhere is pointless," he concluded.

There is precedent for that. In 1999, a private jet carrying golfer Payne Stewart and five others crashed after apparently losing cabin pressure "for undetermined reasons" after takeoff from Florida, the National Transportation Safety Board found.

Fighter pilots were sent up to intercept Stewart's plane after controllers lost contact with it, and they reported its cockpit and cabin windows were frosted over.

The plane flew more than halfway across the United States, apparently on autopilot, until it crashed in a South Dakota field.

Jeff Wise, an aviation journalist for slate.com and author of "Extreme Fear," was unpersuaded on the tire fire/Langkawi landing theory for Flight 370. The pilot, who had been slated to fly to Beijing, did not enter the airline code for Langkawi as a destination in the jet's navigation system, he said.

And the change in course to a different destination was put into the computer that controlled the plane's navigation at least 12 minutes before the co-pilot said good night -- "in very calm tones" -- to air traffic controllers, he told CNN.

"So the change in course was not due to something that happened spontaneously, it wasn't a spontaneous reaction to some emergency in the cockpit," he said. "It had been planned out."

And the jet continued to navigate after it passed Langkawi, making at least two more turns, he said, citing Malaysian military radar. "So there was this careful, planned navigation that was taking place. This was not something that a plane would do on its own; this was something that a human being had to be telling it to do."

In addition, he said, Langkawi lies in neither of the arcs along which investigators believe the plane traveled.

Still, American Airlines pilot John Testrake said events could have played out as Goodfellow described. "It's a possible scenario, but there are a lot of possible scenarios, and that's just one of them," he told CNN.

The plane might also have landed on an island runway that was then covered with trees, he added. "It's anybody's guess. We're speculating; we're just speculating."

The notion of a crew member bent on annihilation may seem far-fetched, but it's possible.

For example, EgyptAir Flight 990 was flying 217 people from Los Angeles to New York to Cairo in 1999 when it crashed into the Atlantic Ocean. U.S. officials blamed a co-pilot, who was recorded repeating a prayer, for deliberately causing the crash, but Egyptian officials blamed mechanical problems.

The Malaysian Airlines flight, a Boeing 777, could have experienced destruction by pilot or crew, some say.

"It's my belief that there was probably some type of struggle in the cockpit where it was one of the pilots that maybe had a meltdown or did something nefarious to the airplane," said Mark Weiss, a retired American Airlines pilot captain who has flown the Boeing 777 and now works at the Washington consulting firm Spectrum Group.

Or there could have been another crew member or an uninvited or invited guest in the cockpit who "was bent on perhaps committing suicide or doing some destruction on the aircraft," Weiss added.

Though allowing guests to enter the cockpit would be improper and "should be disconcerting to anybody," Weiss said, there is no one on a plane who can order them not to do so. Weiss cited a woman's report that co-pilot Fariq Abdul Hamid, 27, invited her and her friend into the cockpit, where they sat from takeoff to landing during a 2011 flight from Phuket, Thailand, to Kuala Lumpur.

"That's an enormous breach of security," Weiss said of cockpit guests.

But none of us will know what really happened in the cockpit "until we have the cockpit voice recorder and the flight data recorder," he added.

And Malaysian opposition leader Anwar Ibrahim told CNN's Christiane Amanpour on Wednesday that he has met Zaharie "on a number of occasions" and said that the pilot is no extremist.

"He supports our multiracial coalition. He supports democratic reform. He is against any form of extremism," Anwar said. "And we take a very strong position in clamoring for change through constitutional and democratic means."

Some have tried to tie Zaharie to Anwar as a family relation.

Anwar's press secretary told CNN that Zaharie is the opposition leader's -- wait for it -- son's wife's mother's father's brother's son.

"What my daughter-in-law told me is that he is a family member, not too close, but she calls him 'uncle,' which is quite common here," Anwar said. "But I know him ... basically as a party activist."

No information has emerged suggesting either of the men flying the jet had a history of mental illness or radicalism. The flight was piloted by Capt. Zaharie, a 53-year-old Malaysian family man with more than 18,000 flying hours compiled during 33 years experience at the airline. He was a veteran flier.

Peter Chong, a friend of Zaharie's, said early this week that he was bothered by speculation about the captain's possible role in the disappearance and questions about possible ties to terrorism.

"I think it is a little bit insensitive and unfair to the family," he said, adding that he knew of no evidence to suggest any ulterior motives on Zaharie's part.

The first officer also has a stable work history: He has been at the airline since 2007 and has compiled 2,763 hours of flying time. He had recently switched to working on the Boeing 777 and had a brief moment of fame when he was featured in a story on "CNN Business Traveler."

Commandeering isn't to be confused with hijacking, a political act in which demands are issued by the hijacker, said CNN national security analyst Peter Bergen.

A commandeering is more idiosyncratic, where motives aren't immediately clear, he said.

Some counterterrorism officials say that could be the case with the Malaysian flight, he said. "The plane could have been commandeered," according to Bergen.

Commandeered flights predate the September 11, 2001, terrorist attacks on the United States, he said.

For example, in 1994, the cargo plane FedEx Flight 705 was commandeered by an employee with a hammer and spear gun who burst into the cockpit and wanted to crash the plane into FedEx's Memphis, Tennessee, headquarters. The crew thwarted that takeover attempt.

In 2000, a passenger with a suspected history of mental illness commandeered British Airways Flight 2069 between London and Nairobi, Kenya, and put the plane carrying 300 passengers into a nosedive until the crew subdued him.

"So commandeering would fit with the few facts that we do know and certainly a theory that we haven't heard a lot of that isn't a conspiracy," Bergen said.

Since September 11, 2001, airlines around the world have put in place procedures to keep unauthorized people out of the cockpit; speculation that those procedures may have been flouted during the flight is just that.

That the plane terminated transponder data before its disappearance has led some experts to suspect a hijacking.

The political motivation for a hijacking, however, would be as mysterious as the plane's whereabouts.

"If you are dealing with hijackers on board the aircraft, whether it was an organized gang, or whether it was some psychologically disturbed individual that ... managed to gain access to the flight, they can neutralize the crew," said Philip Baum, editor of Aviation Security International.

"But then again, there wouldn't necessarily be any communication at all -- as we witnessed on September 11th," Baum added, referring to the 2001 terrorist attacks. "If there was an explosive decompression, if a bomb detonated on board the aircraft, then again there would be no communication."

One possible motive could be terrorism. Authorities haven't ruled out that possibility, though experts are divided on this theory, partly because no one has claimed responsibility.

Still, the absence of a claim of responsibility doesn't mean it wasn't terrorism. "There might be another reason for them not coming forward at this point," said Shawn Henry, former executive assistant director of the FBI. "If it was a terrorist incident ... if this was part of a much larger or broader potential act, and for whatever reason, they wouldn't come forward at this point, but at a later time."

In a less sinister but equally lethal hypothesis, some experts theorize the plane crashed because of a mechanical malfunction -- or perhaps a total electrical failure.

Aviation consultant Kit Darby has said that it's possible there was a power failure, and that the pilot was attempting to get to a runway when the plane lost communications. There's also the possibility that the tail or a wing tore from the fuselage. This particular Boeing had suffered a clipped wingtip in the past, but Boeing repaired it.

Another possibility is that a window or door failed, which would cause the temperature inside the plane to drop to 60 degrees below zero, creating a freezing fog and giving crew members only seconds to don oxygen masks before becoming disoriented and then incapacitated.

The possibility of electrical failure is improbable, but not impossible, according to Jim Tilmon, an aviation expert and retired American Airlines pilot. It "is very, very hard to imagine" because the Boeing jet has so many generators aboard, he said.

"If all the engine generators fail, they still have what's called the RAT (ram air turbine). That's the generator that literally falls out of the bottom of the airplane, has a propeller on it, and ram-air turns that and gives them generating power enough to go ahead and fly the airplane safely.

"Electrical failure -- it'd have to be total ... absolutely incredible, like we've not heard of before," Tilmon said.

The absence of a debris field could suggest that the pilot made an emergency landing on water and the plane then sank intact, but there is still the mystery of the distress signal. There wasn't one.

The possibility of failure of a window or door would be remote, given the Boeing jets' reliability.

Unconstrained by the professional accountability under which the experts labor, some Internet users have offered their own blue-sky theories:

A meteor was reported in the area around the time Flight 370 took off.

This seems to be atop a list of strange theories popping up in the absence of empirical data explaining the plane's disappearance. Given what little is known about the flight path, and the astronomical odds against such an event, a meteor strike seems like an ultralong-shot explanation.

None.

Any such effort would have required the involvement of dozens, if not hundreds, of people, many of whom would have relatives, boyfriends, girlfriends and Facebook accounts. A story as combustible as this one would not remain secret for long.

None, though that has not stopped people from conjecturing, or encouraging others to do so.

"What I have failed to read so far is the possibility that the pilot in command intentionally turned off the engines and performed a dead-stick landing at their intended destination," CNN.com reader Dave Mathews said in an e-mail. "Planes are essentially gliders with power and a 777 is no different, it is simply a big glider which makes zero noise with no power."

He cited the story of the Gimli Glider, an Air Canada Boeing 767 whose captain glided it to safety when it ran out of fuel and lost power during a flight in 1983.

"Whoever is brazen enough to steal a jetliner is brazen enough to perform that maneuver intentionally," said Mathews.

Why would someone steal, hijack or commandeer a 777-200ER only to use it later? "Without passengers, baggage or cargo and stripped down to only the bare essentials for the interior cabin, what you have is basically a flying gas can that could reach any point on earth, and one can only look back at history as to what they would intend to do with it once they reached their target," Mathews said. "The only aircraft better suited for this that they could have targeted was the 777-222LR, the longest range airliner in the world."

James Kallstrom, a former FBI assistant director, said this week that it's possible the plane could have landed somewhere, though he added that more information is needed to reach a definitive conclusion. He referred to the vast search area.

"You draw that arc, and you look at countries like Pakistan, you know, and you get into your Superman novels, and you see the plane landing somewhere and (people) repurposing it for some dastardly deed down the road," he told CNN's Jake Tapper. "I mean, that's not beyond the realm of realism. I mean, that could happen."

An action like the one performed by the Air Canada pilot would best be highly dangerous and would need to be performed under ideal conditions.

And Kallstrom acknowledged the difficulty of basing any conclusion on scraps of information that sometimes conflict.

"We're getting so much conflicting data," he said. "You veer one way, then you veer the other way. The investigators need some definitive, correct data."

None.

None, and -- if you believe that aliens abducted the plane -- we've got a bridge to sell you.

Speculation abounds.

"Everybody wants to get a handle on something right now," former Federal Aviation Administration investigator David Soucie said of the myriad theories. "No one has an answer, so they're going to try to put one on it. So that creates all kinds of assumptions."