It happens every time. An airplane crashes, hundreds are killed, and immediately, before any facts are apparent, everyone wants to pinpoint a cause. It's as though there is a giant void that must be filled, and if it can't be filled by facts, it's filled by theories. Which, of course, are just that -- theories.
It's no different with the crash of MetroJet Flight 9268 in the Egyptian desert. The Russian plane broke apart in midair, killing all 224 people on board. We've heard early speculation of a missile and a fuel tank explosion. There was talk of previous damage to the aircraft's structure from a tail strike. Now we're hearing that a bomb may have been smuggled on board.
But there's a lot more information left to come. Investigators will be analyzing parameters from the flight data recorder that will show how the plane's systems were performing. The debris field will yield important clues. The condition of the wreckage will show if a high-order explosive is to blame.
Confused? Sure you are. So here's a handy guide to wading through news coverage of aviation disasters.
1. The first thing you hear is probably wrong. In the early days after a crash, you're likely to read headlines like "Conflicting Theories Swirl." Ignore it. And if you do read a story with a headline like that, note the sources. Are the people being quoted actually knowledgeable about the situation or are they just speculating? Anybody can speculate.
Does the person or entity being quoted have a vested interest? If an airline says mechanical failure or pilot error is "impossible," remember that airlines get sued over mechanical failure and pilot error. Are airport officials downplaying any possibility of terrorism? Of course they are.
2. At some point you might hear someone say, "Airplanes don't just (fill in the blank)." Many times that person is wrong. For instance, "Airplanes don't just fall out of the sky" was heard after the MetroJet crash. Actually, sometimes they do, although admittedly, it's very rare.
While "falling out the sky" is an amateurish way to put it, airplanes do sometimes plunge to the ground or explode in midair for no immediately apparent reason. But that reason does become apparent over time.
3. Sometimes, whatever is happening is indeed happening for the first time. The pundits might say, "That's never happened before." But that doesn't mean it can't happen. In 2000, two experienced pilots lost control of Alaska Flight 261 as the plane plunged into the Pacific Ocean.
It turned out that the wrong kind of lubrication on a jackscrew had worn away the grooves, rendering the component useless in its job controlling the horizontal stabilizer in tail of the plane. That had never happened before. Until it did.
4. Let's go back to No. 2: "Airplanes don't just fall out of the sky." When USAir Flight 427 crashed in Pennsylvania in 1994, killing 132 people, investigators were mystified. The sky was clear, the pilots were chatting amicably when the plane rolled to the left, turned over, and then headed for the ground, plowing into the earth at 300 mph.
In one of the longest investigations in aviation history, the National Transportation Safety Board determined that the rudder had moved to the opposite position the pilot commanded because of a problem in the servo valve that controlled it.
5. And sometimes, even when it really, really looks like a bomb, it isn't. In the case of TWA Flight 800, the Boeing 747 that crashed off the coast of Long Island in 1996, investigators found tiny traces of residue of a plastic explosive on the interior of the plane. It was puzzling because the condition of the wreckage did not suggest a bomb. But there it was, bomb residue.
But then FAA records revealed the aircraft had apparently been used on the ground as a training site for bomb sniffing dogs, an exercise that required traces of the chemicals in the explosive to be placed in the plane. It wasn't a bomb. The plane exploded in midair when faulty wires sent a power surge into the center fuel tank, igniting the explosive fuel vapors.
A final thing to remember is that air travel is still very safe. NTSB accident investigators work hard to push regulators after each crash to come up with ways to prevent whatever happened from ever happening again. The system doesn't always work, but it has made many aviation safety issues obsolete. Because of aviation's successful safety record, the cause of the next crash could well be something that has never happened before and no one anticipated.
Sylvia Adcock covered aviation safety and security for Newsday from 1996 until 2005. She is the editor of NC State magazine, the alumni magazine of North Carolina State University in Raleigh. The opinions expressed in this commentary are solely hers.