CNN Access: Expert explores crash cause

NEW YORK (CNN) -- Federal aviation officials are investigating the cause of the crash Monday of American Airlines Flight 587 in New York. Some investigators are taking a closer look at the plane's engines, but it's still too early to know exactly what caused the accident.

CNN's Paula Zahn talked to Mary Schiavo, an aviation disaster attorney who is former inspector general with the Department of Transportation, about the possible cause.

CNN: Before we specifically we talk about the CF6 engines, give us your insights as to what you think the cause of this crash was. I know everybody says it's irresponsible to reach any conclusions, but there are some facts that you are certainly familiar with. What do we know? What does that rule in? What does that rule out?

SCHIAVO: Well, just the way that the accident unfolded -- and fortunately we do have another pilot eyewitness account -- it is consistent with an uncontained engine failure, a problem or explosion in the engine. I think just in terms of losing the one engine, losing pieces of the plane, the shower of the parts, is consistent with an uncontained engine failure, which is literally the engine comes apart -- hot, spinning metal, combustible fuel, very consistent with that type of thing.

And we aren't really speculating. What we're looking at is other accidents. That's what the National Transportation Safety Board does. That's what we do when we try to figure out what happened in an accident, and there are literally four similar instances to this one with this kind of an engine.

There was one in Brazil, one in Puerto Rico, one in Philadelphia that you just mentioned in your report. And then, of course, also people look back to the Sioux City tragedy, which was a GE engine -- not this one, but so there are similar circumstances where engines have come apart. … So we're not just guessing when we say it looks like the engine. There are similar circumstances.

CNN: So that, you think, is sort of the No. 1 focus of this investigation at this hour?

SCHIAVO: I'm sure that it is, and also if you did have this occurring in flight, what probably happened is the wing on which you lost the engine, you would obviously lose your left turn towards that. The pilot then, apparently from another pilot eyewitness report, tried to turn back to the airport. That is -- I'm sure those facts will differ as the hours and days go on in the investigation.

But that would be consistent if you had … tried to maintain your altitude and get back. And at that point, if you were turning and were no longer able to control the plane, you could have a structural failure and parts of the plane literally would start coming off, depending upon the forces on that aircraft.

CNN: You and I both listened to, as did our audience, this report by Charles Feldman that preceded you where we talked about the airworthiness directive issued by the FAA. Given your experience with these kinds of cases, once a directive is issued, how much pressure is brought to bear on the airline to live up to that directive?

SCHIAVO: Well, once a directive is issued -- and there actually are several directives pertaining to these engines, not just one -- the airline is given a matter of months or in some cases a matter of years to comply with it. In this case it was an inspection that we're focused on. By the way, there was another AD in the pipeline. It was open for comment until December 31 concerning GE engines, and they hadn't issued that one yet. That would have reduced the life cycle of some of these engines by as much as one-third. And then the airlines basically are given time to comply.

They don't have to rush out and do it unless it's an emergency order. Sometimes in the wake of these tragedies, if it was the subject of a pending order, the FAA will change it to an emergency directive. That happened after the last airline tragedy. They had an opened unfinished AD and then they made it an emergency.

But ordinarily the airlines are just given their time deadlines, and then no pressure is put on them unless they fail to meet the deadline. In that case, they can apply for a waiver to extend it.

CNN: I don't want to go too far down this line accusing GE of having done anything wrong here, but you heard what the spokesperson told Charles Feldman, that they did, in fact, re-examine specific parts of this engine and they could find nothing to change. If that's the case, then they're saying that publicly, what does that mean?

SCHIAVO: It could mean a lot of things. For example, in the Sioux City accident it was a flaw that was embedded in one of the disks, literally out of the factory door, and they had actually seen it on previous inspections of this plane. I think on one of the previous inspections, the crack was actually visible. On these planes they had to do ultrasonic examinations, which was required by the AD, and if it was within tolerances or if it didn't fall within the replacement, then the carriers that operate these engines were free to proceed.

And so in many cases you are relying on experience gathered in the field and you're relying on the FAA to either agree or disagree and push this to an AD. So the manufacturer in some cases, you know, may be going on past experience and think that some things are within tolerance. Sometimes you learn an awful lot from an accident as well, but you know the AD isn't always the answer on everything.

CNN: How concerned are you about the security in place at maintenance facilities where work is done on engines of this sort?

SCHIAVO: That's a big concern because there isn't much external security. The repair facilities and the airlines that use them are supposed to maintain their levels of security, etc., but there's very little, and I'm sure that the FBI, since this plane had been in maintenance the day before this accident, has probably grabbed all those records and has started questioning those people -- maybe has questioned them all at this point. I'm sure that was their first thought as well.