How crash probes make aviation safer
Investigators for the Comair flight will look at everything from pilot behavior to runway signs.
One of the first aviation maxims aspiring pilots learn is that every accident is caused by a chain of events. And every accident is a lesson to learn from.
Investigators for the National Transportation Safety Board (NTSB) are now trying to understand exactly what prompted the crew of Comair Flight 5191 to take off from a runway that was too short for the plane's size.
It's the first step in exhaustive analysis done after every accident, which has helped the nation's aviation industry to be one of the safest in the world. Sunday's crash, which killed 49 people and left one – the copilot – critically injured, was the first deadly accident in US commercial aviation in more than three years. In the coming months and years, investigators will scour every aspect of the crash – from the performance of the plane to the orders issued from the control tower to how much sleep the pilot had had. The knowledge gleaned will then be used to enhance the safety of everything from pilot training to navigational technologies to the way planes are designed.
Aviation analysts contend that accumulated knowledge and advances in technology will eventually result in only two kinds of aviation accidents: those like Sunday's crash, where the cause is fairly obvious from the start, and those like TWA Flight 800 that crashed off Long Island in 1996, where the cause will never be known for sure.
"Aviation safety in the future is going to be a lot different than it was in the past," says Darryl Jenkins, an aviation expert and consultant based in Marshall, Va. "Since we've been through so many things, and learned so much, accidents will either be obvious and a tragedy like yesterday or we won't know what to make of it, as in Flight 800, where we think we know but we won't really know."
Aviation investigators did conclude that the cause of the Flight 800 crash was an explosion in the fuel tank, but they were never able to conclusively determine what sparked it – whether it was a corroded wire, excess heat from the air-conditioning system, or some other factor. As a result, the NTSB recommended a series of changes, including regular fuel-tank inspections and changes in future fuel-tank designs.
While the NTSB has confirmed that Comair Flight 5191 was on a runway that was too short to give it enough speed to lift off, investigators still need to determine why that happened. The causes could range from someone forgetting to turn the lights on for the proper runway to overgrown grass that obscured the signage to the pilot being distracted.
"Accidents are rarely caused by one thing but usually a chain of improbable events," says Stuart Matthews, president and CEO of the Flight Safety Foundation in Alexandria, Va. "So if you can disrupt one link of the chain, then similar accidents may be averted in the future."
For instance, if investigators determine that the grass was too high and impeded the view of signs to the proper runway, the NTSB may recommend that airports be required to cut their grass during the summer X number of times a week. Or if lights identifying the proper runway had blown out, it may require changes in light-bulb maintenance.
"That's how we improve safety," says Mr. Matthews.
If the accident is eventually determined to be pilot error, it could also lead to changes in, say, how much sleep pilots are required to have between flights or the type of training they receive.
"That tells you how incredibly safe this system is despite how fearful some people are of flying," Richard Gritta, an aviation analyst at the University of Portland in Oregon. "And people are always working to make it safer."