Alaska Air Crash Flight 261
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JIM LEHRER: And with us once again is Lee Dickinson, a former member of the National Transportation Safety Board. He’s now the director of Exponent Failure Analysis, an engineering and investigative firm that specializes in transportation accidents.
Welcome again, Mr. Dickinson. What could possibly have happened to that stabilizer? What are the possibilities?
LEE DICKINSON: Well, there could be a number of possibilities, Jim. You’ve heard from Chairman Hall and John Hammerschmidt that they have information from a number of different sources — the cockpit voice recorder, information from the aircraft control tapes, which are really the Federal Aviation Administration’s tapes. They have indicated that they had a jammed stabilizer, in this case a jammed horizontal stabilizer.
So your viewers will understand, the rear end of an MD-80 is known as a T-tail. In other words it’s basically looking like so. My right hand is the top portion is the horizontal stabilizer. The vertical stabilizer would be my left hand. The horizontal stabilizer, our understanding, it jammed according to the crew, which means that it was in some-up or some-down condition. That is driven electrically from the cockpit. It can be overcome by manual controls. There are things called elevators on the rear end of the horizontal stabilizer that a crew or that the pilot can help to keep the nose of the airplane either level, up or down. Apparently that jammed and that’s what the Safety Board is investigating now.
JIM LEHRER: The manual part jammed. I mean, first of all the electronic part didn’t work and then the manual part must have also jammed, right?
LEE DICKINSON: Well, we don’t know the second part of your answer. As a matter of fact, they’re trying to figure out if the first part also happened. Apparently according to the crew it did jam. One of the things that the Safety Board will be looking at is listening to the cockpit voice recorder, what the people are saying, what the crew was saying, what the captain and the co-pilot are saying. Since we now know that the flight data recorder has been recovered they will want to look at and read out the information from the flight data recorder.
If it is a sophisticated flight data recorder, and it’s my understanding that this airplane is only eight years old, that one of the variables or one of the parameters on this flight data recorder should indicate what was going on with the horizontal stabilizer. If that’s the case, that will tell you what the aircraft was actually doing and they will then coincide that or they will synchronize that with the information from the cockpit voice recorder. So, you’ll see what the airplane was doing at the same time that you’re hearing what the cockpit crew are saying.
JIM LEHRER: Now, just so we understand this, the stabilizer, this horizontal stabilizer, that is a basic part of making this airplane fly, is it not?
LEE DICKINSON: That is absolutely correct. That is what really controls the pitch of the airplane. Does it fly level? Can it ascend, nose up or nose down?
JIM LEHRER: And the pilots, when they move the stick, the yolk, that’s all part of that. I mean, this is not some obscure button that they have to push or anything like that?
LEE DICKINSON: Well, you’re basically on target with that. It is controlled by the yolk. They also have usually an electric trim, which is a button which helps to dampen out, if you will, any outside turbulence. That’s tied in not only to horizontal stabilizer but the elevators that I was mentioning, which are raised or lowered at the aft-end of the stabilizer itself.
JIM LEHRER: Do all airplanes have these things?
LEE DICKINSON: Yes they do.
JIM LEHRER: Has there been a history of problems with them?
LEE DICKINSON: Not that I’m aware of. Yesterday there was information early on that I think it was either yesterday — there was an American Airlines that —
JIM LEHRER: Yeah. Outside of Phoenix.
LEE DICKINSON: That’s correct. It’s my understanding that the Safety Board has removed or the flight data recorder has been removed from that American Airlines MD-80 and sent it to Washington, D.C. And they will read that out and see what was going on with that airplane to see if it has anything to do with or how it helps in this investigation.
JIM LEHRER: The announcement on that one used the same word “jammed,” that the horizontal stabilizer jammed and that’s why the pilots returned to Phoenix.
LEE DICKINSON: That’s my understanding.
JIM LEHRER: But as far as you know, this has is not a common thing, right?
LEE DICKINSON: That’s correct. One thing I have to caution you or your viewers on also is that because it looks like right now the Safety Board is focusing on the stabilizer, the horizontal stabilizer, that does not necessarily mean that that was a trigger event. One of the things that the Safety Board will do when they’re completing the investigation is to see whether or not something else may have happened which then indeed may have caused the stabilizer to jam, which then could have caused something else.
JIM LEHRER: You told Gwen Ifill the other night that usually it’s not just one thing that goes wrong. A lot of things have to go wrong at the same time, right?
LEE DICKINSON: That’s typically what happens in an accident, that’s correct.
JIM LEHRER: So, when you heard what the NTSB investigators said, that the plane –when they use — when they say inverted, they mean upside-down. This plane was flying upside-down for a while, right?
LEE DICKINSON: Again, you have to be careful about that. They said the word inverted. And that also was tracking what a number of the witnesses said. But inverted could also mean if it was beginning to roll and then maybe go down in what’s known as a roll, at some portion of that roll the plane would indeed be inverted. That doesn’t necessarily mean that it’s flying level.
JIM LEHRER: I see. But corkscrewing and all of this sort of thing, is that consistent with a horizontal stabilizer problem?
LEE DICKINSON: That could be because if you can’t get any movement and if you get a jamming of the stabilizer, then you don’t have this pitch control that we were talking about before. But usually pilots are taught or trained for different scenarios where they may get a problem with the horizontal stabilizer.
So, again, this is something that the Safety Board will have to be thoroughly looking at — not only what could have happened but what was the crew doing. We also know that they were talking to maintenance to their company in Seattle to try to troubleshoot, if you will. Apparently according to Chairman Hall today they were doing this for about 30 minutes. There’s no question that the Board will be looking at exactly what the crew was doing, what the procedures call for and what should have been going on.
JIM LEHRER: Is that a common practice where if you’re flying along and you have a problem that you get on the radio with your maintenance folks back home?
LEE DICKINSON: I won’t say it’s common but it’s not uncommon. If indeed there is a problem that the crew cannot handle themselves, the smartest thing to do would be to get in touch with your company to find out what should they do if indeed they are presented with a problem.
JIM LEHRER: Finally Mr. Dickinson, we have of course been — there have been several major airplane crashes lately. The Egyptair, TWA, where they never have found — they haven’t found out yet exactly what happened. In some cases it’s been several years — less time in the other. Based on your experience, does it look like from this early few days that we’re going to know what happened in that Alaska Airlines crash?
LEE DICKINSON: I firmly believe that the Safety Board will determine not only what happened, Jim, but why. And that’s really the probable cause. I think they will make that determination.
JIM LEHRER: Do you think that what we know leads you to believe that this mystery — this will not be a mystery that will go off into the books forever.
LEE DICKINSON: This mystery will be solved.
JIM LEHRER: Mr. Dickinson, thank you again.
LEE DICKINSON: You’re welcome.