The EgytpAir Crash
Aviation Analyst John J. Nance Talks About Flight 990 - October 31, 1999

November 1, 1999 - Investigators, having lost hope of finding any survivors, are now searching for the wreckage, bodies and a reason for the crash of EgyptAir Flight 990.

What caused the crash and the deaths of the 217 people aboard? Was it a mechanical failure or terrorism? Those are the questions for investigators. To discuss the EgyptAir crash we were joined by aviation analyst John J. Nance.

Moderator at 3:04pm ET
Welcome, John J. Nance. Let's begin.

Danny from [208.202.161.150] at 3:04pm ET
How long can you suggest this investigation may last?

John J. Nance at 3:06pm ET
Complex accidents, and they are always complex, take a minimum of 6 months to just assemble the basic facts. More detailed analyses can add as much as a year or two, as in the case of the USAir 737 crash investigation. In this case, because of the water location of the wreckage, I would be surprised to see a final report inside 18 months at the minimum. If the answers are not readily apparent when the cockpit voice recorder and flight data recorder are debriefed, that 18 months could turn into years.

Mimi from [207.245.51.134], at 3:06pm ET
When a plane goes down the way Flight 990 did, do passengers feel that the plane is going down?

John J. Nance at 3:10pm ET
When a commercial aircraft goes into a dive as steep and precipitous as the preliminary radar data seems to indicate, a well known psychological profile suggests the response on the part of the passengers to be utter disbelief and more of a shock condition than one of feelings of impending mortality. In this particular situation, we don't yet know enough of the flight path of the aircraft from cruise altitude to the water, nor do we know anything about what started this fatal sequence, leaving us unable to speculate regarding what the passengers would have heard, thought, or felt. Obviously, this was not the same nightmarish scenario, at least at 33,000 feet, as with TWA 800 where the opening round of the problem was the splitting in half of the aircraft. While we don't know whether this 767 began to break up on the way down, there are some indications that perhaps it hit the water relatively intact, and that makes it quite different.

joes from fx.dialisdn.com at 3:12pm ET
John, in 1991 the Lauda 767 crash was said to be from the engine thrust reverser engaging. My question is are the thrust reversers automatically engaged or done manually? Also, do both thrusters engage together or separately?

John J. Nance at 3:14pm ET
While the problem that permitted the #2 engine thrust reverser on the Lauda Air flight in 1991 to come open at a high engine power setting should have been fixed throughout the 767 fleet many years back, the fact is this remains a complex system. To answer your questions specifically, it is the pilot's hand that determines whether both thrust reverse levers are deployed at the same time on the ground and it has always been felt that there is far too much danger in automating this function to justify making the job of deploying thrust reversers yet another "autopilot" function.

Michael H. from [128.220.193.79], at 3:15pm ET
What are some possible mechanical failures that could cause such an airplane to fall so quickly?

John J. Nance at 3:18pm ET
One of the difficulties that I think for all of us associated with aviation safety are having with the early facts on this accident, is that none of us can conceive of a specific failure which could cause the flight path that is beginning to emerge. This doesn't mean that it can't be a mechanical problem or material failure anymore than it means that it has to be a result of sabotage. In fact, one of the strange aspects is that the facts as we know them (or believe we know them) do not point to either conclusion. Could I formulate numerous possibilities to explain a 23,000 ft/min dive? Of course. But the point is that what little we know of the flight path just doesn't suggest any simple explanation, or for that matter any one explanation.

marshall from [207.181.81.195], at 3:18pm ET
What type of routine inspection is done during a return stopover or segment on an international carrier? Do these carriers contract American maintenance technicians while on these international segments and are some service issues not dealt with while on a return flight segment?

John J. Nance at 3:22pm ET
Every airline, especially foreign airlines, approaches the task of maintenance away from their home base somewhat differently. While I can't say what Egypt Air's method is, the majority of foreign carriers with limited flights into the U.S. use contracted maintenance personnel who, for the most part, will only work on the aircraft if something is specifically reported as inoperative. The pilots make a certain ground check and there are other very quick checks done at the gate by maintenance personnel, contract or otherwise. But this is not the sort of in depth, major maintenance that could find a deeply embedded problem with the aircraft.

Jeremy from [209.218.103.44], at 3:22pm ET
What kind of catastrophe could occur that would keep the pilot(s) from relaying a may day or warning of some kind to a control tower?

John J. Nance at 3:25pm ET
Any emergency that challenges a flight crew's control is going to cause you as a pilot to focus all your attention on maintaining or recovering control and not talking about it on the radio. While we, as pilots, are quick to bring our brethren on the other end of the radio frequency (air traffic controllers) up to speed, you'll only do that when the emergency has been stabilized because, after all, they can't reach out and fly the airplane for you. In this instance, it's just too soon to know for certain, but it would be a safe bet that these pilots, like all professional airmen, were fighting until the very last breath to regain control and overcome whatever happened to their airplane.

Moderator at 3:29pm ET
Thanks to aviation expert John J. Nance for joining us today.

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