Rudder Failure at 35k Feet - Mayday Air Disaster
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Short filmTranscript
00:0035,000 feet above the Bering Sea.
00:04Anchorage, northwest 85.
00:06Confirm that you are aware that we have declared an emergency.
00:09A Boeing 747 is in serious trouble.
00:12We can't do that. There's too much traffic.
00:13We're calling this a red emergency.
00:15A red emergency is preparing for the worst.
00:18The crew can barely control the plane.
00:21It was a very confusing situation.
00:24It was something that they had never done in training.
00:27They need all the help they can get
00:29to have any hope of bringing the plane
00:31and its 386 passengers safely to the ground.
00:36If there's ever going to be a time
00:38when you fly the perfect approach,
00:40it's got to be this one.
00:44Made it, made it.
00:57Northwest Airlines Flight 85 is making its way over the Bering Sea.
01:13It's after 5pm.
01:15Dinner service has ended
01:17and passengers are settling in for a long flight.
01:22The massive Boeing 747-400 has just flown over Alaska
01:26and is now almost halfway through
01:28a 13 and a half hour journey from Detroit
01:31to Japan's Narita Airport.
01:33Hello, gentlemen.
01:34Frank, how are things?
01:3735,000 feet.
01:39Captain John Hansen is a career pilot.
01:42He's also a flight instructor for the Boeing 747.
01:47Six and a half hours into the flight,
01:49he's about to hand over the controls.
01:52On long journeys, it's common to have two flight crews.
01:57The trip was long enough that we put on a full augmented crew.
02:02We had two captains and two co-pilots.
02:05They fly in shifts to prevent fatigue.
02:08Why don't you guys give me a ding about 20 minutes
02:10before you want me back up here, OK?
02:12Mike Fagan, a Vietnam vet with 25 years flying experience,
02:16is the fresh first officer.
02:18Everything was normal,
02:20and we didn't expect to have any problems.
02:22We've flown this flight many, many times.
02:24Frank, I'm taking the lasagna. You get option B.
02:28Does option B include starving?
02:30He is joined by Captain Frank Guy,
02:32who has over 11,000 hours of flying under his belt.
02:39Pilots refer to this aircraft as the Queen of the Skies.
02:43It's equipped with a private cabin for the flight crew.
02:46Here, Captain Hansen and his first officer, David Smith,
02:50will have a five-hour rest break before returning to the flight deck.
02:55Dave Smith had worked with me,
02:57and we were going to read for a while,
03:00perhaps nap in the bunk and wake up for descent to Tokyo.
03:10Are you sure you're not hungry?
03:12Trust me, I'm good.
03:15Flight 85 is more than six hours from landing at Narita.
03:27The aircraft took a dramatic roll to the left.
03:30It went from 35 through 40 degrees of pain.
03:37For no apparent reason,
03:39the pilots have lost control of their planes.
03:43Oh!
03:49The airplane took a lurch, like nothing I had ever felt before,
03:54and I kind of had to catch myself.
03:59It was a very sudden, yawing movement.
04:03It's the type of thing you only feel in a simulator
04:06when they're doing a flight simulation.
04:09Captain Guibe has only moments to react.
04:13Do we lose an engine?
04:15Do we still have engines?
04:17We'll have all engines, that's not it.
04:19The lives of 386 passengers hang in the balance.
04:25The airplane was kind of shaking,
04:27and I knew the autopilot had been disconnected.
04:30It was quite obvious that there was something wrong.
04:34In a matter of seconds, Captain Guibe has disconnected the autopilot,
04:38pulled back on the control column, and leveled the wings.
04:43But something is still seriously wrong.
04:49Frank, you got it?
04:51Yeah, I think I've got it.
04:53If it's not the engines, then we have a problem with the rudder.
04:57It's not the rudder.
04:59It's not the rudder.
05:01If it's not the engines, then we have a problem with the rudder.
05:05The pilots have leveled the plane,
05:07but they are still having difficulty controlling it.
05:11The warning system confirms Guibe's suspicion.
05:14Yaw camber lower.
05:17A malfunction of the rudder system.
05:20The rudder controls the plane's yaw,
05:22its movements from left to right, as it flies.
05:26It directs airflow to keep it flying straight.
05:30Less than a year earlier,
05:32American Airlines Flight 587 lost control of its rudder system
05:36and crashed into a neighborhood in Queens, New York,
05:39killing everyone on board.
05:42We were very well aware of that,
05:44and there had been quite a study done on that,
05:47so we had actually just reviewed that event in flight planning.
05:55This plane is in danger of suffering the same fate.
06:00Because of its size, the 747 has both an upper and lower rudder.
06:05They normally move in unison.
06:07For some unknown reason,
06:09the lower rudder has deflected 17 degrees to the left,
06:13and it's stuck there.
06:16The captain tries to keep the plane flying level and straight.
06:21He uses foot pedals to control the upper rudder
06:24and the control column to move the ailerons.
06:29But he knows it's a stopgap measure that may not work for long.
06:34I've got the airplane in the radios.
06:36You get the comm and see if there's a procedure for this.
06:40The comm, or cockpit operating manual,
06:43provides a list of procedures for emergency situations.
06:47It says not to remove any pressure from the hydraulics, that's all.
06:50That's not very helpful.
06:52Is there anything else, or any other systems failing?
06:59Not so far.
07:01Hydraulics control several vital components, including the failed rudder.
07:05More failures could spell disaster.
07:08How far to Marita?
07:10About six hours.
07:14Flying that far without full control of the plane is a huge risk.
07:18P3, get them back.
07:21When you're in the bunk, you're used to hearing the P3 only at times
07:25when it's time for a shift change.
07:28When you hear it at an odd time, it means come back,
07:32because something out of the ordinary has happened.
07:35Anchorage is two hours behind us.
07:37Call them and declare an emergency.
07:40We're turning around.
07:43Anchorage, this is Northwest 85.
07:46But even contacting Anchorage is a problem.
07:49Anchorage, this is Northwest 85.
07:52Air traffic control centers have a limited range.
07:55In the middle of the sea, between the two continents,
07:58the plane is in a dead zone.
08:01No one in Anchorage knows they're in trouble.
08:05In the cabin, passengers don't know the scale of the problem.
08:09Many passengers assume it was only turbulence that caused the sudden jolt.
08:14See if you can reach 19.
08:16The pilots attempt to contact another flight that's closer to Alaska.
08:20Northwest 19, this is Northwest 85.
08:23But the signal is weak.
08:27Northwest 19, this is Northwest 85.
08:31This is Northwest 19. Go ahead.
08:33We have an emergency on board. Can you relay to Anchorage?
08:37Roger. Stand by.
08:39OK. Let's turn this around.
08:44The plane goes into a very wide right turn.
08:54Anchorage Control, this is Northwest 19.
08:57Northwest 19. Go ahead.
08:59Northwest 85 is requesting an emergency landing.
09:02What is the nature of the emergency?
09:04Hard over, left rudder.
09:08The rudder is crucial for turning the plane around.
09:11Without it, the captain is forced to improvise.
09:15We had no idea what the problem was.
09:18So Frank was very cautious on using the rudder,
09:21which means that he had to use full aileron to control the aircraft.
09:24But in the meantime, the aircraft is in a slip.
09:26And a slip is when the aircraft is not in a coordinated turn.
09:30The tail is off in one direction, the nose pointed in the other direction.
09:34In other words, it's a slip that goes like this.
09:36Like a race car driver skidding through a turn,
09:39Captain Guibe is close to losing control.
09:44Let's move it.
09:49What's happening?
09:50We've declared an emergency and we're headed back to Anchorage.
09:54Indications?
09:56Lower rudder is hard over 17 degrees to the left.
10:01We don't know why and it's not responding.
10:04We don't know what else is wrong yet.
10:07It took both hands to fly the airplane.
10:09We didn't know at that point whether the rudder was coming apart.
10:14All we knew was it was definitely a rudder problem.
10:18This has never happened before.
10:20The pilots haven't been trained for this malfunction.
10:23There's no procedure in the cockpit.
10:27And the manual is of no use.
10:34We're going to have to make one up.
10:3635,000 feet over the Bering Sea,
10:39and an hour and 40 minutes away from the nearest airport,
10:43the pilots of this massive 747 are in uncharted territory.
10:51For the 386 passengers on flight 85,
10:55the anxiety over the sudden dive has subsided.
10:58No one in the cabin is aware of the potentially fatal drama
11:02still unfolding in the cockpit.
11:07Without full control of the plane's rudder,
11:10the crew needs to fly another 1,300 kilometres to anchorage.
11:16Frank was the junior captain. I was the senior captain.
11:19And when I saw him battling the controls,
11:23I decided that I was going to take over.
11:26Frank, you've done a hell of a job, but I think I'd better take over now.
11:29If anybody's going to ding this thing up, it's going to be me.
11:32I have no problem with that.
11:34OK.
11:35OK, Mike, you're going to have to take control while we switch over.
11:39Are you ready?
11:42I'm ready.
11:43First Officer Fagan must now hold the yoke steady
11:46as Captain Guibe relinquishes control of the plane.
11:50I have control.
11:52Any mishandling of the controls could send the plane into a fatal spin.
12:01The same delicate balancing act
12:03transfers control of the plane to Captain Hansen.
12:07I was pretty appalled at how much force it took to fly this big, beautiful airplane.
12:13If the airplane is flying, even lousy, it's flying,
12:18and that's the bottom line, and it's headed towards an anchorage.
12:21So we're good to go for a while.
12:24Now we could begin to devote some thought to other things that had to be done.
12:29The crew has no idea how badly the rudder is damaged.
12:33It could be seconds from tearing off altogether.
12:42I can't tell whether the damn rudder's trying to leave the airplane.
12:46What do we tell the cabin?
12:49We decided the passengers really should know,
12:53so we wanted a liaison with the cabin, and Frank offered to do that.
12:58I'll go back and tell them.
13:00The more they know, the better.
13:02I agree. I think we should tell them exactly what's going on.
13:11Kathy, we don't know if things are going to get better or worse.
13:16Every single crew member knew that something major had happened to that aircraft.
13:21We've turned back to anchorage, and we're going to make an emergency landing.
13:24The captain didn't try to hide anything, didn't try to pull any punches.
13:28He just flat-out said how things were and that it could possibly be a very rough landing.
13:35Kathy, we're calling this one a red emergency.
13:38Red emergency is, of course, preparing for the worst.
13:42There may be a crash landing. There may be damage to the aircraft.
13:47There may be injury and or death to the passengers and or yourself.
13:52Hello, ladies and gentlemen. I'm Captain Frank Gebe.
13:56We are dealing with a malfunction at the moment, and our crew is dealing with the situation as best we can.
14:01We need everybody to remain calm, and please give your flight attendants your complete attention.
14:08I cannot stress how important your complete cooperation will be in order for us to make it to the ground safely.
14:15The passengers, for the most part, were fairly calm.
14:20I promise I'll update you with any new information as it becomes available.
14:25Thank you very much for your attention, and I'll talk to you later.
14:29After a few minutes, you could hear some people crying a little bit.
14:34You could see people looking around. You could see fear.
14:42We need to talk to SOC. We need suggestions.
14:46We can reach them on HF.
14:48The Systems Operations Center in Minnesota may be able to help,
14:52but to reach that far, the pilots must use high-frequency radio, which has a weak intermittent signal.
14:59HF radio is like when you were a kid and your best friend lived next door and you talked to him between your bedrooms
15:06with two Campbell soup cans with a string between them.
15:09About that level of sound quality is just awful.
15:11And ask them to wake up John Doherty for us.
15:15I was at home the night of the call, just relaxing after a day in the office, enjoying a movie.
15:24But I was on call, and those pagers would go off, and sure enough, it did.
15:30John Doherty has worked with Captain Hansen for several years.
15:34I knew John very well, so I had a face, a person, a pilot I knew very well in my mind's eye.
15:41I knew John Doherty had a better knowledge of the 747-400 than anybody at Northwest.
15:50But Captain Hansen has no idea when his friend's help might arrive,
15:54and keeping the huge aircraft flying level at 35,000 feet is becoming increasingly difficult.
16:00The control wheel was shaking, because the whole airplane was shaking.
16:04He decides to descend to a lower altitude,
16:07You ready to do this?
16:09All set.
16:11But with a crippled plane, this normally routine procedure will be another risky maneuver.
16:17OK. Let's go.
16:20You want to do it very carefully.
16:22So they're handling the controls under this really unusual circumstance
16:26as carefully and gently and as delicately as they can.
16:31Both the same, not great.
16:33We had to be very careful how we flew this airplane.
16:36The tail might be coming apart, the rudder might be just barely hanging on,
16:41or it could be a hydraulic problem.
16:4628,000.
16:48They make it down to 28,000 feet without further incident,
16:51but the plane is still shaking.
16:5528,000.
16:57They make it down to 28,000 feet without further incident,
17:00I think I got this area.
17:02OK.
17:04but the force required to fly the damaged aircraft has taken its toll on the captain.
17:09John.
17:11Yeah, my leg's starting to cramp up.
17:13I've had a tough time holding this together.
17:16The physical effort that was required was considerable.
17:22We were pushing so hard with our leg on that rudder pedal
17:25that we could only do it for about ten minutes.
17:28You're going to have to take it.
17:31Are you ready?
17:32I'm ready.
17:34All right.
17:36Nice and easy.
17:42And then Mike would come in as I released.
17:46It wanted to go back the other way.
17:48You had to make it go where you wanted it to go,
17:51and you have to use the cross control,
17:53so you're using the muscles in your shoulder and in your back,
17:56and we would lock our legs.
18:00And then when I would release, I'd kind of get limbered up again.
18:05Still more than an hour away from Anchorage,
18:08the flight attendants prepare the cabin for a red emergency.
18:13We did what we were trained to do.
18:15You just kicked in, and you would make sure
18:18that everything on the counter is put away,
18:21make sure all the crew bags are stowed and where they should be.
18:28Everyone, to a person, cooperated with what we asked them to do.
18:33I remember coming to a family of three,
18:36and they asked me if I was afraid,
18:39and I hate to admit it, but I did briefly consider lying,
18:42but then I decided that wasn't what I should do.
18:45Yeah, I'm afraid too, but we have the best pilots.
18:52Flight 85, we have John Doherty on the line.
18:55Operations has finally been able to connect the pilots with John Doherty.
19:01John, have you been briefed on this? You know what's happening up here?
19:05Yes. I understand you have a control problem.
19:08ICAS is showing we have a hard over lower rudder.
19:11They were facing really a very confusing situation.
19:14They knew they were confronted with something unique.
19:18It was something that they had never done in training,
19:21something they had never seen in training,
19:23nothing we'd ever talked about in ground schools.
19:27Comm is not telling us much. We're about an hour out of anchor.
19:31Rick, what do you think?
19:34Well, don't remove any power from the hydraulics, but other than that...
19:40And I knew from listening to John
19:43that what we had in the books wasn't going to be a help to him.
19:47There are going to be some circumstances
19:49where a pilot is going to have to figure out what to do on his or her own.
19:5430 minutes pass before Northwest 85 is in range
19:58to talk to the Anchorage Control Center directly.
20:01Northwest 85, we have you on the radar.
20:04Anchorage Northwest 85, confirm that you are aware
20:07that we have declared an emergency.
20:09We have emergency equipment standing by.
20:12We will request runway.
20:18The plane must fly over the Aleutian Mountain Range
20:21to reach Anchorage International Airport.
20:24The airport itself is also surrounded by mountains.
20:28We said, OK, six rides is the runway we want
20:31because it'll give us a 20-mile final,
20:33and it's a great runway with an ILS approach
20:36and it's long.
20:38OK, six right it is. Let's make sure we get it right the first time.
20:41As far as the missed approach is concerned, we're not going to do one.
20:45We're just going to do it right the first time.
20:48We're going to put it right on the spot.
20:50There is no margin for error.
20:53The pilots know they have only one shot.
20:57What do you think, Mike?
21:00Maybe we should start configuring for landing early, lower our altitude.
21:05They're still 40 minutes away from Anchorage,
21:08but the pilots decide to configure for a landing.
21:12They want to see how it will affect their crippled plane.
21:16If something goes wrong, this may give them more room to recover.
21:20OK, we can take it over Cook Inlet, lower to 14,000,
21:23and then see what happens.
21:2614,000 feet is a real nice intermediate altitude.
21:30It's good, thick air, and it's high enough yet
21:34that if something got worse and control deteriorated,
21:37you'd have room for a recovery.
21:40This is Northwest 85. We would like to descend to 14,000 over Cook Inlet.
21:45We can't do that. Lots of air traffic in that airspace.
21:49The airspace over Cook Inlet is the busiest corridor in this part of the continent.
21:54If they lose control of the plane again, they could collide with another aircraft.
22:00This is an emergency aircraft. This is the payment port of action.
22:06OK, we'll clear everyone out of your way.
22:10The jumbo jet slowly descends to 14,000 feet.
22:16OK, flap 5.
22:21Flap 5.
22:23As he adds flaps, Captain Hansen can only hope the plane maintains stable flight.
22:29Next comes an even bigger test.
22:32Gear down.
22:35Gear down.
22:37Lowering the massive landing gear will increase drag and reduce airspeed.
22:43The plane handles the new configuration without any problems.
22:47But there are new worries about the damaged rudder.
22:52You feeling that? Oh, yeah.
22:57The rudder is tied to airspeed and altitude.
23:00The lower you get, the further the rudder goes out.
23:03So then it required more rudder, more aileron.
23:06And that was physically exhausting.
23:10Mike, my leg's starting to cramp up. Are you ready?
23:15I'm ready.
23:22John Doherty is still on the line to the crew.
23:25He offers a suggestion.
23:27Have you considered adding 20 knots to your approach speed?
23:31No, we hadn't thought about that. We'll do it.
23:34The extra speed may help make the plane more controllable.
23:46Hello, ladies and gentlemen.
23:48We're in for a bit of a rough landing.
23:51When we touch down, there's going to be quite a jolt.
23:55We'll tell you when to brace for impact.
24:01As Northwest Airlines Flight 85 approaches Anchorage,
24:05the pilots and Doherty continue planning for an uncertain landing ahead.
24:10We discussed how are things going to be as we fly the approach,
24:13what flight control, what management issues in terms of flight paths we're going to encounter there,
24:18and then how are we going to manage directional control during the landing rollout,
24:22what stopping issues we're going to have, and so on.
24:25The decisions they face in the next few moments
24:28will make the difference between life and death.
24:33OK, we can't do this anymore. Let's use the engines.
24:37Dave, get on the levers. One and two up, three and four down.
24:41Just minutes from touchdown,
24:43the pilots increase power to the left engines while reducing power to the right.
24:48This uneven thrust should help keep it straight.
24:52But there is a danger.
24:54No one knows how badly damaged the rudder is.
24:58If it tears off while the engine thrust is uneven,
25:01the pilots will lose all control.
25:06On the ground, they are preparing for the worst.
25:14I'd give $1,000 for a rear-view mirror right now.
25:24John, what do you think?
25:27Doherty has been scouring charts and manuals.
25:30He reminds the crew of another problem to consider.
25:33On landing, don't forget the rudder is attached to the nose bearing.
25:37And when that happens, Mike, I'll take the tiller and the brakes, you take the yoke.
25:40Once the nose touches down,
25:42the damaged rudder may cause them to lose control of the plane
25:45at more than 300 kilometers an hour.
25:54I flew the approach all the way down and I thought,
25:58if there's ever going to be a time you fly a perfect approach,
26:02it's got to be this one.
26:05I became extraneous at that time,
26:07so somewhere along around 7,000, 8,000 feet on the way down,
26:11I signed off with the crew.
26:14I'll talk to you when you're on the ground.
26:16We'll talk soon.
26:19You know, I gave John whatever blessing I could give at the moment,
26:24probably understated in typical pilot fashion,
26:27and I was off the line.
26:30Between the frigid waters of Cook Inlet
26:33and the towering Alaskan mountains,
26:35Anchorage International Airport awaits the arrival of a stricken 747.
26:40Northwest 85, we have you on our radar.
26:47The passenger plane is about to take off.
26:50It's going to be a long flight.
26:52It's going to be a long flight.
26:54It's going to be a long flight.
26:57The passengers and crew of Northwest 85
27:00are now moments away from an emergency landing.
27:07As I was putting my own seatbelt on,
27:10I remember thinking to myself,
27:13is this all there is?
27:15As in, am I done here?
27:18Am I going to be alive when this is over?
27:21And I thought about my kids and my husband and my home.
27:26Northwest 85, cleared to land.
27:29Emergency equipment standing by.
27:32Roger, cleared to land.
27:34The crew still has no idea what will happen
27:37when the plane touches the ground.
27:39There were close to 400 passengers in that airplane
27:42and a crew of 18,
27:44and some of them people that I knew personally,
27:47like John and the other pilots in the crew,
27:50so waiting was hard.
27:53OK, everyone, here we go.
28:00Touchdown in five. Prepare for impact.
28:03Brake, brake, brake!
28:16You got it? I got it.
28:18As planned, on touchdown,
28:20First Officer Fagan takes the control column.
28:23Captain Hansen guides the front wheels with the tiller.
28:26The timing is critical.
28:28One false step and the plane could shoot off the runway.
28:41We got it.
28:44Woo!
28:48Good job, Mike.
28:50Good job, guys.
28:52So what do we do for encore?
28:55Not that.
28:57Everyone in the cockpit was finally able to exhale,
29:00and we just went...
29:03Oh!
29:13Once we were given the signal that it was OK...
29:17Please remain seated until the seatbelt light is off.
29:20I knew that I had to get up and go to that entry door
29:23and get these people out of this airplane.
29:26We did what we were trained to do.
29:28We did a great job.
29:30Controllers can see what the pilots can't.
29:33That's quite the rudder you got there.
29:36Must have been a hell of a ride.
29:39Oh, yeah, it was a real joy ride.
29:46Almost two hours after the emergency began at 35,000 feet,
29:50all 404 people on board are safely on the ground.
30:01Well, when I heard the crew was safe, of course,
30:04it was an incredible sense of relief.
30:06These guys had been tested, and they'd done a fabulous job.
30:09So, you know, it was really joyful.
30:12I mean, a sense of grace, accomplishment, joy, satisfaction.
30:18It was all good.
30:22The pilots have narrowly avoided a fatal crash.
30:25But what caused them to lose control in the first place
30:28is a question that desperately needs to be answered.
30:33Northwest is just one of many airlines flying the 747-400 every day.
30:41Thousands of passengers around the world now face a potential risk.
30:49Carolyn DeForge of the NTSB will oversee the investigation.
30:53It appeared to be a very dramatic event,
30:56and it definitely seemed like something we needed to follow up on
31:01and try and understand what had happened.
31:06Investigators immediately discover a trail of hydraulic fluid
31:10leaking from the back of the plane.
31:12It was very surprising to us when we found out what type of failure had occurred
31:16and that the effects it had had on the aircraft's controllability.
31:22The pilots' foot pedals are linked to the rudder
31:25through a hydraulic power control module, or PCM.
31:29When the pilot presses on the pedals, the PCM changes the hydraulic pressure,
31:34and that's what moves the rudder.
31:37They opened up the access panels in the tail,
31:41and they noticed that the end cap on the control module had separated.
31:46The end cap is a circular piece about 2.5 inches in diameter,
31:52and it had completely fractured all of the way around its diameter
31:56and had then fallen off.
31:59With the PCM broken, the pilots had no way to control the lower rudder.
32:04The failure of this one piece of engineering
32:07nearly brought down the entire plane.
32:10The power control module is shipped to the NTSB headquarters in Washington.
32:16Close examination reveals exactly how the failed part caused the rudder to jam.
32:22When the end cap came off, it allowed a piston inside the module
32:27to move further than its design limit was intended,
32:31and that is what resulted in the rudder hard over.
32:38But why the module's end cap failed in the first place is still a mystery.
32:44It was certainly something that was not anticipated by the designers,
32:49and when we examined the hardware,
32:52it was definitely beyond the scope of what you normally encounter as an engineer
32:58when you're doing a failure investigation.
33:00Normally you see something that's an internal failure,
33:03not an actual mechanical failure of the housing itself.
33:07Sylvie Dionne is a metallurgist specializing in airplane components.
33:11The manifold material was an aluminum alloy,
33:14which means that it's actually aluminum metal
33:17that's mixed in with a bit of copper, with magnesium, with zinc,
33:21and the purpose of adding these other elements is to make it stronger.
33:25The aluminum alloy used to make this part is extremely resilient.
33:30It should never break apart like this.
33:34Doing failure analyses like this on failed parts is a bit like being a detective
33:40because you're looking for clues as to what caused the occurrence,
33:44what caused the material to fail.
33:48The size and shape of the crack tells investigators that the module wore out over time,
33:54what's called metal fatigue.
33:56However, this is almost impossible for them to believe.
34:03A Boeing 747-400 is built for long hauls, 12 to 15 hour flights,
34:09and its parts are built to last decades.
34:13My understanding was the mean time before failure for this item was something like 30,000 years,
34:19which is basically saying, well, we don't think this part was ever going to fail.
34:24The 747-400 is in high demand.
34:27More of these massive planes are being manufactured every year,
34:31with the same control module that failed on Flight 85.
34:36If this crucial system is wearing out prematurely,
34:40investigators need to figure out why, before it leads to a fatal disaster.
34:47The fact that this had a purely fatigue failure with no apparent origin to it,
34:53such as a deficiency or a defect,
34:56made us question the material properties of the housing itself.
35:01Investigators send the unit back to the manufacturer for extensive metallurgical testing.
35:09Metals are made up of little crystals, which metallurgists call grains,
35:14and if the grains are too small or too large or not the correct shape,
35:19the material may have a different strength, different ductility,
35:22different resistance to propagation of a crack.
35:25A visual examination of the metal provides no insight into why it failed.
35:32One of the best techniques for revealing if a part contains cracks or surface defects
35:37is to use fluorescent dye inspection.
35:43The part is examined under UV light,
35:46and the defects will appear as bright lines or bright dots that are very visible.
35:52But the exhaustive tests reveal that the material itself was not to blame.
35:59Investigators still can't explain the failure.
36:02It was driving all of the group crazy.
36:04We were very frustrated when we realized it.
36:07All of the paths we chased down didn't give you that ah-ha, eureka moment.
36:16Investigators wonder if something in this place is causing the failure.
36:22What explains history could have caused the module to break down prematurely?
36:27What the records reveal is surprising.
36:30Northwest was the launch customer for the 747-400,
36:35and this one was the first in the line of 400s that Northwest flew.
36:40It was the oldest production 747-400 in the world.
36:47And that's not all.
36:49The records also show that this very 747-400 was used as a test plane
36:54before it was even sold to the airline.
36:57Could rigorous testing have somehow led to the failure of the power control module?
37:03The plane had flown for 55,000 hours and taken off more than 7,000 times.
37:10That's more take-offs and landings than most 747s with that number of hours in the air.
37:16This discovery leads the investigation in an entirely new direction.
37:22We were concerned that it had been exposed to more stress than we had expected,
37:27and that that may have caused it to fail.
37:30Each time a plane takes off and lands,
37:33its systems are put through more stress than when it's simply flying through the air.
37:40We were very concerned about those operators in Asia that used the 747-400.
37:45On short-haul flights.
37:47This module, however, is already broken.
37:50There's no way to test it.
37:52Checking all the units on the rest of the fleet is not a practical option.
37:56You would have essentially had to have grounded the fleet to remove all of the units.
38:02As a preemptive strike against future failure,
38:05the NTSB recommends that airlines test the power control module more vigorously and more regularly.
38:12We instituted a repetitive inspection cycle requirement.
38:18But the root cause of the failure is never found.
38:25Four years later, an Air France cargo plane is forced to make an emergency landing.
38:31Once again, the lower rudder has failed on the 747-400.
38:37The circumstances are strikingly similar to Northwest Flight 85.
38:42The unit was sent to Parker Hannafin in California for repair.
38:46And when they opened the box and looked at it, their eyes got really big.
38:50They immediately quarantined it and called everyone and said,
38:53oh my gosh, you're not going to believe what just showed up on our doorstep.
38:57If the Air France module shows signs of metal fatigue like the one on Flight 85,
39:03then investigators may be a step closer to explaining the mysterious failures.
39:08We immediately focused in on the fracture surface again in the same area
39:13and did many of the checks that we had done the first time around.
39:18But this case seems to be different. There is no sign of fatigue.
39:22Instead, they find a manufacturing defect.
39:25We actually found a deficiency in the bottom of the threaded bore section.
39:30We found a very sharp radius at the bottom of the threads,
39:34which is where the crack had propagated from.
39:37While finding the cause of this latest failure is significant,
39:41it has done nothing to help explain the failure on the Northwest Flight four years earlier.
39:46Was it overloading? Was it a progressive failure?
39:51Was it exposed to something in the environment that caused it to fail?
39:56Without knowing the why, you can't really take the appropriate corrective action.
40:01And as an investigator, that's frustrating.
40:05For the second time, a part that was never meant to wear out has nearly brought down a 747.
40:12With one of the two near tragedies still unexplained,
40:16investigators desperately need to find a fail-safe measure that will protect passengers in the future.
40:26Four years after Flight 85's heart-stopping emergency landing in Anchorage,
40:32the cause of the 747's rudder failure is still unknown.
40:38Now the same part has failed on another flight.
40:42The next failure could be deadly.
40:46We still don't know, actually, the root cause of the Northwest failure.
40:52But because of what we found with the second Air France failure,
40:56we needed to take corrective action to prevent similar failures from occurring.
41:01Investigators recommend attaching special plugs to the control module.
41:06In the event of another failure,
41:08these new pieces will prevent the rudder from moving too far in either direction.
41:13The changes that we've made to the control modules in the 747-400 fleet
41:18will prevent any future events of a rudder hardover.
41:23An airworthiness directive from the FAA makes it mandatory for every 747-400
41:29to be fitted with this new technology,
41:32eliminating the risk of another failure.
41:38But still there is another question to consider,
41:41one investigators seldom have the luxury to contemplate.
41:46With a catastrophic failure of the rudder system,
41:49why didn't Flight 85 crash?
41:52One reason, the very design of this 747.
41:57Having a split rudder is definitely an unusual feature of this airplane.
42:02And in this case it worked in their favor in the sense that
42:07if there had only been one rudder and the actuator of that rudder had failed,
42:11then 100% of the yaw control would have been deflected,
42:15which would have magnified the problem.
42:19But technology alone did not save 404 lives.
42:26In 1985, China Airlines Flight 006 also went into a sudden roll.
42:34But that flight plummeted nearly 30,000 feet
42:37before the pilots were able to regain control.
42:42How had Flight 85 escaped the same fate?
42:47If Frank hadn't reacted the way he had,
42:50we probably would not be here to tell the story.
42:55Frank, have you got it? Yes, I think I've got it.
42:58Captain Guibe's actions in the first few seconds
43:01were critical to saving the plane.
43:04But what got it safely to the ground is another story.
43:08Every pilot in that cockpit knew what was going on.
43:12Risks were being assessed and so on.
43:14On landing.
43:15Don't forget the rudder's attached to the nose steering.
43:18And when that happens, Mike, I'll take the teller on the brakes and you take the yoke.
43:22Cockpit resource management is really what enabled us
43:27to think this thing through and get the airplane on the ground.
43:31I am proud to say we were like a well-oiled machine.
43:34We all did what we were trained to do.
43:36Touchdown in five. Prepare for impact.
43:38And not one single person fell apart.
43:41What do we tell the captain?
43:44The guys that we had in the cockpit were just tremendous.
43:47Everybody communicated.
43:49I'll go back and tell them.
43:51The more they know, the better.
43:53I agree.
43:54I think we should tell them exactly what's going on.
43:56I think this crew did a phenomenal job
43:58in getting this aircraft back on the ground safely.
44:01In 2003, the Airline Pilots Association
44:04awarded the crew of Northwest Airlines Flight 85
44:07with the Superior Airmanship Award.
44:09More important than the award was the fact that
44:12we got the people on the ground safely.
44:16We got it!
44:20In this day and age of automated cockpits,
44:23hand flying is in danger of becoming a lost art.
44:28We have to remember as pilots
44:31that we are there because of our flying skills.
44:36We had prepared so well for this thing
44:38that failure was not an option.
44:58NASA Jet Propulsion Laboratory, California Institute of Technology