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Were Engine Inspection Times a Factor in Plane Crash?
Aired November 12, 2001 - 14:57 ET
THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.
THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.
AARON BROWN, CNN ANCHOR: Miles O'Brien in Atlanta -- Miles, I think as many of you know from our coverage over the years of space and other aviation related stories -- I won't tag you with the title expert, but I will say you know a good deal about all of this stuff, far more than I.
I know there are some things you want to talk about based on what you've heard. I wonder if you could answer the question Judy raised though, about why one engine has more -- went more hours without being inspected than the other? One engine on the plane had been inspected, I think, 640 hours ago, the other almost 10,000 hours ago. I gather they swap these engines out from time to time for a variety of reasons?
MILES O'BRIEN, CNN CORRESPONDENT: Yes, that's exactly what happens. They swap them through. It's not like there a pair of engines that follow each and every jet as it goes through its lifetime. These engines are swapped out, a new one is put on, the airplane put back into service, that engine is overhauled, and so on and so forth.
And so it's not uncommon for one engine to be what they call a relatively high-time engine, ready for an overhaul fairly soon, twinned up with one that just came out of the engine shop. That's not uncommon at all.
Let's bring in another expert. And we will call him an expert. John Wiley is an airline flight instructor, airline captain who has spent a lot of time in cockpits.
On that issue of high-time, low-time engines, one of these had almost 10,000 hours on it. It sounds like a lot of usage. But with these engines, not necessarily so.
JOHN WILEY, AIRLINE PILOT: Not necessarily so. The engines are long life. The biggest thing that effects the engine is the heat that is on the engine. And so, as you mentioned, you may have an engine that has come out of the shop, that is relatively a low-time engine. You may have an engine that has had no anomalies, no problems, whatever. It's remained on the wing for a long period of time.
O'BRIEN: Let's talk about this portion of any flight. This is really -- I think it's probably safe to say the most precarious time of any flight, the takeoff and the immediate departure because there is so little margin for error.
As we go down the runway here at -- and we are told that it was runway 31 left, which would have been this runway right from there to there. At any given point as that plane goes down that runway, the crew is spring loaded for a failure and for an abort scenario, correct? If you lose an engine at that juncture, they are going to do their best, depending on where it is, to stay on the ground, right?
WILEY: You have a number of different points as you're on the runway. The crews, basically, have a briefing as they head down, before they get on the runway. And they discuss primarily three speeds, which we talked about a little bit earlier.
The V1 speed -- prior to V1, anything that happens prior to V1, we reject the takeoff. After V1, the airplane -- even if we lose an engine, should be able to continue the takeoff in the remaining runway and get airborne.
So we have a VR speed, which is a rotation speed. That's the point at which the pilot pulls back on the control column, rotates the nose into the air approximately 13 to 15 degrees up and the airplane becomes airborne. And our third speed, which we refer to as Velocity- 2, or V2.
O'BRIEN: And at this juncture, the turn begins almost immediately. The plane begins to bank to the left, not to the right as we indicated earlier. We have since looked at the charts and the standard departure is a left turn swinging out to the south and to the east somewhat. And as they're turning around here, even on a good day, this is a very busy time to be in a cockpit, correct?
WILEY: You have a very high workload.
O'BRIEN: What is going on at this juncture as they turn out. They are getting -- obviously ascending. And they are adjusting the throttles, adjusting the flaps on the wings, that sort of thing.
WILEY: We don't know at this point and time at what point the engine failed. We don't know at what point the engine separated from the aircraft.
If the engine failure was first acknowledged while they were on the runway, they would have gotten a master caution light, associated with a fire warning bell or a master caution bell. That would have alerted the crew that they had the problem.
The physical loss of the engine from the airplane plane may not have been discernible to the crew. From their position where they are sitting in the cockpit, it's very difficult to see the engine that far back.
O'BRIEN: All right.
As we get to the point where the primary impact was, no radio call from the crew. What does that lead you to believe? No indication. WILEY: High work load. The crew is dealing with the problem. Normally after we get airborne we'll climb to 1,000 feet. At that point and time, we'll start retracting the flaps, trying to get the airplane into configuration to accelerate. We'll lower the nose and accelerate as we start incrementally bringing the flaps up, and getting ready for the -- deal with the emergency.
Normally, the big thing is is that during this period of time, the first three rules of aviation: fly the airplane, fly the airplane and fly the airplane. So they're not, at that point and time, consumed with dealing with the emergency necessarily.
O'BRIEN: All right.
Let's take a look at the Airbus A300, 600 version, of which American has 35 in the fleet. A couple of things to consider. First of all, the fact that this, an engine, has come off of a wing. That in and of itself is not a situation which necessarily means you're going to crash, correct? It's designed to fly on one engine, correct?
WILEY: Well, you have to remember the engine is providing propulsion. The wings are providing the lift. So in fact, if the crew, or if somebody may have called out, they said we've lost an engine. "We've lost No. 1," meaning the left engine, "we've lost No. 2," the right engine. A crew member calls that out, they may not have known that the engine physically separated from the aircraft.
What they're looking at is a set of instruments that are telling them that they've lost thrust from that engine. So they'll make the call out. They'll start preparing to deal with the single engine takeoff continued in this two-engine aircraft. But unless the wing surface is damaged, they still should be having the normal amount of lift off that wing. They've just divided their amount of thrust in half.
O'BRIEN: All right.
And one of the key things they will be looking at is if in fact there was some damage caused to these flaps, which increase lift at a slow flight, which occurs immediately after departure.
And one other thing, Aaron, which we should point out. In the tail of every aircraft is the two flight data recorders, the flight data recorder and the cockpit voice recorder. In this case on the Airbus A300, it's a digital flight data recorder, which provides literally hundreds of channels of data, of information, which is captured in that box.
We know that that box has been recovered. There will be a treasure trove of information for investigators in there, giving them some indication as to what happened here -- back to you in New York.
AARON BROWN, CNN ANCHOR: Before you guys get away -- and we're waiting for the mayor here -- just a layman's question. If an engine comes off at that low an altitude, at that speed when they trying to get -- when they're taking off, wouldn't it alter just the balance of the plane and therefore the stability of the plane?
O'BRIEN: The question is, John -- I'm going to repeat it somewhat because he doesn't have an earpiece in -- the question is, losing the engine would alter, obviously, the balance of the aircraft in such a way that it might be difficult to handle. But it's not out of the envelope, if you will, of control for the aircraft, right?
WILEY: You would have -- you should still have sufficient control, with the ailerons and the spoilers, to continue to level the airplane, to maneuver the airplane laterally, so the departure of the engine on, again, unless it damaged the surface itself, the airplane should still be flyable.
O'BRIEN: And that's a key point to remember here, Aaron, is there are three hydraulic systems on the Airbus A300. There are only so many places you can route this plumbing through a wing in order for it to control the surfaces. And if, in fact, there was, you know, something spit out of this engine -- a piece of titanium going at high speed because of some catastrophic breakup of this engine as it fell off -- it could very easily sever the series of hydraulic lines which go along here.
Now, what's really worth pointing out here is, once you have lost hydraulic pressure at any one given place in the circuit, you lose hydraulic pressure to every other control because it's a closed circuit of fluid, if you will. And once it leaks, you are out of business. That's why they have triply redundant hydraulic systems.
But you may recall some years back here, in the crash of United Airlines flight in Sioux City, Iowa. There was an engine, the tail of a DC-10, which had a catastrophic problem. It severed all the hydraulic lines at once and caused the crew to lose hydraulic control. They had to bring it down using just the controls of the throttles of the two remaining engines on the wings -- a heroic effort. Several people died, but several people did in fact live because of those efforts.
So the hydraulics are the key thing to look at here. If something fell off and a piece of shrapnel, if you will -- titanium shrapnel -- spinning blades came out of that engine, it might very well have severed all those hydraulic lines.
BROWN: Miles, thank you. That sounded pretty expert to me. Thank you very much.
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