Mayday Air Crash Investigations - S09 E02 - Cockpit Chaos
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00:00For investigators trying to solve a plane crash, the most important tool can be the black box.
00:10It records every detail in the cockpit.
00:14Look at this. There's Charlie.
00:17And tells investigators about vital conversations.
00:20Damn, it's starting to rain.
00:22Northwest 255, runway 3, center, clear for takeoff.
00:30But in the crash of Northwest Airlines Flight 255...
00:38I haven't ever been to an accident at that scale.
00:41It wasn't what investigators heard on the tape.
00:44TCI was unsaid.
00:46It was what they didn't hear...
00:48It was checked.
00:51...that would lead to an astonishing conclusion.
01:00The 80's, 90's.
01:21Detroit, Michigan.
01:25August 16, 1987.
01:277. It's 8 p.m. and the city is sweltering. 25 kilometers from downtown. Detroit Metropolitan
01:42Airport is one of the busiest airports in the United States. More than 1,100 airplanes
01:52use its four runways each day. Today, one of those is Northwest Airlines Flight 255, bound
02:03for Phoenix, Arizona. Captain John Mouse is in command. A Las Vegas native, 57-year-old
02:12Mouse is a veteran pilot. His first officer is 35-year-old David Dodds of Galena,
02:22Illinois. Why don't you tell them we're ready to go? Both have years of experience on this
02:29type of aircraft. The MD-80 is also known as the Super 80 and is the second generation
02:36of the DC-9. The MD-80 was quite a bit longer. It had more powerful engines, so it could carry
02:43more people. For that reason, it was a better moneymaker for the airlines than the DC-9 was.
02:50Look at this. The sky between Detroit and Phoenix is filled with storms. Several are moving quickly
03:08towards the airport. There's a line here. For the crew, it's been a long day. We're about 25 miles wide.
03:16If we get out of here pretty quick, we won't have a delay. They've already flown from Minneapolis,
03:21Minnesota, to Saginaw, Michigan, and then Detroit. Phoenix is their next stop on the way to Santa Anna,
03:27California. If we wait till after the storm's here, we delay is going over Waterville. If they're delayed
03:34by weather, they may not make their final destination. Let's get out of here before it starts raining.
03:45The plane's 149 passengers are also eager to leave. Paula Sheehan and her family have been visiting
04:03relatives. They're heading home to Arizona. Her daughter, Cecilia, is only four years old.
04:09Looks like bags are all in. Why don't you tell them we're ready to go?
04:16We're in 255 and Delta 50. Flight 255 is running half an hour late.
04:26Northwest 255. Clear to go. Okay, we're clear to push. Let's do the checklist.
04:35Brakes. Set. Windshield heat.
04:39It's on. There's the pumps.
04:43It's six. Got the pressure controller. Checked.
04:47Auxiliary hydraulic pumps and pressure. On and checked.
04:52Yeah. It's starting to rain.
04:55To beat the storms, they need to leave immediately.
04:58Slight beacons.
04:59Come on. Four start checklists.
05:04Flight 255 begins moving from the gate to the runway.
05:07Northwest 255.
05:09But because of the weather...
05:12Northwest 255. Now exit at Charlie Runway. Three center.
05:17The ground controller gives them a last-minute runway change.
05:27Okay, out to Charlie for three center. Northwest 255.
05:32Charlie for three center ready.
05:33Okay.
05:34Okay.
05:38Ladies and gentlemen, we're currently number one for departure.
05:41We should be rolling in a couple minutes.
05:43May the tenants be seated. Thank you.
05:46Blacker than hell out there.
05:51By the time they get to the new runway, they're 45 minutes behind schedule.
06:09Northwest 255. Runway three center. Clear for takeoff.
06:12Within 17 seconds, 65,000 kilograms of passengers and aircraft hurtle down runway 3C.
06:23But moments before liftoff, mouse discovers he can't engage the autoprople.
06:32What's dealing?
06:34TCI's on set.
06:36His computer isn't in takeoff mode.
06:39They're on now.
06:40TCI's on set.
06:41Okay.
06:41Okay.
06:43Clamp. 100 knots.
06:46At 313 kilometers per hour...
06:48V-1. Rotate.
06:52The pilots angle the plane's nose up for liftoff.
06:56Then something else goes wrong.
07:00Just under 50 feet from the ground, the aircraft begins rolling from side to side.
07:05Power lifeguard copter, one, zero, two.
07:14It rolls left and strikes a light pole.
07:18Out of control, flight 255 slams into the ground.
07:23Skids along a highway.
07:26And disintegrates when it hits an overpass.
07:28I prayed that everybody made it, but I thought it was just a small plane because it happened so quickly.
07:41I didn't know it was a bigger plane, and it was just awful.
07:45I saw the plane come through the products, a big fireball.
07:50What we got dispatched was a rainy Sunday night.
07:52And then he said, there's an airliner down, and our mood kind of just changed.
07:58And the one guy looked at me, Dan, and said, well, I hope it's a small one.
08:07When we pulled up, we saw the cockpit and the word West written on the fuselage.
08:11And we looked at each other, and he said, it looks like a big one.
08:15There's a trail of scorched bodies and debris more than a kilometer long.
08:22Just minutes after impact, paramedic Tim Schroeder is on the scene looking for survivors.
08:28I have never been to an accident at that scale.
08:32We were struck by the magnitude of what we were seeing, the large scale of it.
08:38It was just, it was almost overwhelming.
08:41From the little that's left of flight 255, it is unlikely they'll find anyone alive.
08:48I buddied up with Dan, and we both started entering the wreckage.
08:52It was probably a minute went by, and Dan actually heard a noise.
09:00He asked me a couple times, you know, do I hear anything?
09:03And I said, no.
09:04And then finally I heard it, and it was more like a faint cry.
09:10When I turned my head to the right, I saw an arm underneath the seat.
09:15One, two, three, lift!
09:25She was covered in some blood and some soot.
09:31Somehow, four-year-old Cecilia Sheehan has survived the crash.
09:35But she's badly injured.
09:40Tim Schroeder races her to hospital.
09:42We have a four-year-old girl found alive in the wreckage.
09:44She has a very weak pulse.
09:47If Cecilia survived, perhaps others have as well.
09:53Rescuers spend hours looking through the wreckage for more survivors.
09:56But their efforts will be in vain.
10:00We actually covered anything that was a body or a body part with a yellow blanket.
10:07It was just nothing but, like, a sea of yellow blankets, basically.
10:13Northwest Airlines said 154 passengers and crew aboard the plane died in the crash.
10:17Both Captain Mouse and First Officer Dodds are killed in the crash.
10:24Two other people died when their cars were hit by the plane.
10:28This is the second deadliest airplane disaster in U.S. history.
10:37Recovering in hospital with serious head wounds is Flight 255's lone survivor,
10:43four-year-old Cecilia Sheehan.
10:44Despite her injuries, doctors say she will live.
10:49Maybe God was on her side that night.
10:55Within hours of the crash,
10:57investigator Jack Drake and his team from the National Transportation Safety Board
11:01begin looking for clues.
11:04Drake is a former Navy pilot
11:06who's been involved in hundreds of crash investigations.
11:10You know when you're at a crash site
11:12because you get this combination of burned plastic and kerosene
11:15and sometimes combined with fire-retardant foam
11:19that has its own distinctive odor.
11:22You know you've arrived when you smell it.
11:32Drake and his team treat the crash site like a crime scene.
11:35Our team consisted of 12 or 13 specialists,
11:41some of whom go to the site
11:42and some of whom do their work elsewhere.
11:46They set out to examine every piece of wreckage
11:49to discover what went wrong.
11:55They have responsibilities for looking at different parts
11:58of the wreckage debris
12:01and do qualitative analysis of those parts.
12:08We always look for the recorders first.
12:10They're frequently referred to as black boxes,
12:13although they're usually orange.
12:16The information is usually well protected
12:18because they're encased in a steel box
12:21that is both heat-resistant and crash-resistant.
12:25Since the 1960s, commercial jetliners have been required
12:31to carry flight data and voice recorders.
12:34The CVR was first introduced in Australia
12:36following the 1960 crash of a Fokker F-27.
12:41The devices must be able to withstand an impact of 3,400 Gs
12:45and temperatures as high as 1,100 degrees Celsius.
12:49The cockpit voice recorder is intact,
12:57but the flight data recorder suffered some damage in the crash.
13:03They may hold the only clues that can help solve this accident.
13:08Both recorders are sent to the NTSB lab in Washington, D.C.
13:12John Clark is Drake's flight performance engineer.
13:23His first task is to make a map of the debris
13:26left behind by Flight 255.
13:32When I first started seeing the wreckage,
13:35your mind immediately starts turning to
13:38sorting out where it hit, how it hit,
13:42not where the wreckage ended up,
13:44but those first few inches where the airplane was coming down.
13:50Clark looks for ground scars and other impact marks
13:54and interviews witnesses
13:56to piece together where the plane fell and how.
13:59and that kind of gives you a sense of those last moments,
14:05what the airplane was doing when it hit the ground.
14:08Clark begins to understand the final moments of Flight 255.
14:13According to witnesses, as it lifted off,
14:16it couldn't climb and flew in a nose-high position.
14:19That could indicate that the plane didn't have enough power
14:28to get off the ground,
14:30that it didn't have enough speed,
14:32or that high winds prevented it from lifting off.
14:38Witnesses provide investigators with a critical clue.
14:41You saw fire coming from the engine.
14:44Several, including an air traffic controller,
14:47saw flames coming from the plane's engine before the crash.
14:51Damn!
14:52The engines become the first focus of this investigation.
15:04They look for evidence of an internal failure.
15:07The plane suffered an engine failure.
15:09Investigators soon learn that less than a month earlier,
15:12one of the plane's engines was damaged
15:14when it was hit by a foreign object.
15:16It was repaired and was being monitored by mechanics
15:19to see how it performed.
15:20The team studies the remains of the engine for clues
15:30that it had either caught fire or shut down on take-off.
15:37Despite what the witnesses saw,
15:39they find no evidence of fire or of a massive breakdown.
15:44The information suggested that the engine operation had been normal.
15:49Clear.
15:50100 knots.
15:54The flames were the result of the fuel tank rupturing
15:57after the plane hit a light pole.
15:59The fire didn't cause the crash.
16:05If Drake and his team are to solve this mystery,
16:08they need to be certain about what happened
16:10in the last few seconds before Flight 255 crashed.
16:14Well, I think probably the best physical evidence is what was on the flight data recorder.
16:21The flight data recorder doesn't tell you about weather.
16:23It tells you about aircraft parameters,
16:26aircraft performance, essentially, second by second,
16:29even at quarter-second intervals in some parameters.
16:31But NTSB technicians can't recover all the information from the recorder.
16:40They send it to the manufacturer to see if they can recover the lost data.
16:44While he waits for news about the flight data recorder,
16:53Jack Drake looks more closely at the weather on the night of the crash.
16:56There was some convective or thundershower-type activity that had moved through the area,
17:04and its impact on the accident required a lot of analysis.
17:07Drake wonders how the storm affected Flight 255.
17:16He listens to the cockpit voice recorder for clues.
17:20He discovers the menacing weather was a concern to the crew.
17:25Let's get out of here before it starts raining.
17:28Jesus, look at this.
17:31Drake sees that there were several storms along the flight path,
17:34and they were getting closer to Detroit.
17:38There's a line here and a line between these two.
17:43There's another one here about 25 miles wide.
17:49Thunderstorms can create a very dangerous threat to pilots.
17:54Since there was severe weather in the area,
17:57we always worry about microbursts.
18:00Microbursts occur when columns of air shoot down to earth.
18:06As a plane passes through, winds batter it from all directions,
18:10making it difficult to control.
18:17In a microburst condition, you can get very shifting winds
18:20and also vertical winds that try to push the airplane into the ground.
18:24So you can get loss of airspeed, a very rapid rise in airspeed,
18:28and then also actually push the airplane toward the ground.
18:31And it requires very aggressive flying on the part of the flight crew.
18:35This unusual weather condition had killed before.
18:39In 1985, a microburst brought down a Delta Airlines flight in Dallas,
18:45killing 137 people.
18:47At the time of the Detroit accident,
18:59there was no device at airports to accurately detect microbursts.
19:03Instead, pilots relied on reports from other crews.
19:11Jack Drake discovers that 27 minutes before liftoff,
19:14Captain Mouse and 1st Officer Dodds received such a warning.
19:20Ground, this is 722.
19:22You just had a microburst out here.
19:23The dust just exploded down there.
19:28Investigators suspect that a microburst
19:30may have slammed Flight 255 to the ground
19:33as it tried to lift off.
19:35It was right after departure when the accident occurred.
19:38If they had struck a very strong microburst,
19:41that would be a candidate for one of the possible causes.
19:48Satellite images taken at the time of the crash
19:50and weather data from the airport's sensors
19:53show that there were storms near the airport
19:55at the time of the accident.
19:57But there's no evidence of a microburst.
20:02Wind and rain, but nothing that could be a microburst.
20:05Around the time of the crash,
20:07the airport's sensors did record
20:09a dangerous gust of wind on the runway,
20:11powerful enough to set off alarms in the tower.
20:18Upon further investigation,
20:20Drake discovers that Flight 255
20:22was still at the gate at the time of that alarm.
20:25So the winds couldn't have brought the plane down.
20:28Sign beacons.
20:28But they did have a huge effect
20:31on Captain Mouse's flight plan.
20:35The crew's pre-flight dispatch package
20:37stated that they would take off from runway 21 left.
20:43But with the sudden change of wind direction,
20:46ground control sends Flight 255 to runway 3C,
20:50the shortest of three available runways.
20:53Northwest 255 now waves to the Charlie runway 3C.
21:09Okay, out to Charlie for 3C,
21:12Northwest 255.
21:14Charlie for 3C, right.
21:16Okay.
21:19Controllers try to have planes take off into the wind.
21:22The additional wind flowing over a plane's wings
21:25gives it more lift
21:26and helps it get off the ground.
21:29Taking off into the wind is safer.
21:31But taking off on the shorter runway
21:33now means First Officer Dodds
21:35must recalculate the plane's takeoff weight.
21:39There's a runway change.
21:41You have to determine if the weight of the aircraft
21:44will permit it to accelerate and climb out safely.
21:47And this varies depending on the length of the runway,
21:49temperature, altitude of the airport.
21:52Perhaps First Officer Dodds made a mistake in his calculation.
21:5744-4.
21:59How can we do that like for a full airplane?
22:02If he did,
22:04it could explain why the MD-80
22:06wasn't able to make it off the ground.
22:09Runway 3C simply wasn't long enough.
22:11Using calculations based on average weight of luggage
22:20and passengers on board,
22:22Drake's team confirmed Dodd's estimate.
22:25The plane weighed 144,047 pounds,
22:29well below the allowable limit for runway 3C.
22:33It should have been able to get off the ground.
22:35Drake's investigation has hit another dead end.
22:41He and his team are running out of possibilities.
22:46Until technicians can decode the damaged flight data recorder,
22:50the team must rely on the physical evidence
22:52that's been found at the crash site.
22:54But when investigators study the cockpit's center console,
22:59they're forced to consider an almost unimaginable cause.
23:03Is this the way it was found?
23:04To get the plane off the ground,
23:09the flaps on the wings should have been extended
23:11to the 11-degree position.
23:13But the way the flap handle is damaged
23:15suggests the plane's flaps were retracted when it crashed.
23:21The pin had left a mark.
23:25This happens because the aircraft comes to a very sudden stop
23:29and the handle jangles around
23:30and it's a metal-to-metal contact
23:34that's exaggerated by the impact.
23:38Don't stay on.
23:42That indicator was that the flaps were zero
23:45or fully retracted
23:47and the slats were retracted as well.
23:51Flaps and slats are extensions
23:53that slide out of the back and front of the wing.
23:56They make the wing bigger,
23:57which increases the amount of lift they can provide.
24:00They must be extended for take-off.
24:05If the slats are retracted,
24:07for the most part, with today's modern jets,
24:10the airplane is not capable of flight.
24:12It's not capable of flight.
24:15If the crew tried to take off with the flaps retracted,
24:19it would be an astonishing blunder.
24:23V-1, rotate.
24:24But a pilot who was lined up directly behind flight 255 on the runway
24:30is certain the plane's flaps were extended.
24:33You're sure the flaps were extended?
24:37Pilots in other aircraft
24:38that were close to the point where the take-off had begun
24:42were telling us that they thought
24:44the flaps and slats were deployed to a normal position.
24:50Investigators can't be sure
24:51whether the flaps were extended or not.
24:57The clues they need
24:59lie somewhere in the sea of debris
25:01recovered from the crash site.
25:06Eventually, investigators find the evidence they need
25:09inside a section of the plane's left wing.
25:12Each component of the slat system
25:15has its own drive system,
25:17and one of those was interrupted
25:18by the light pole that passed through the wing.
25:2118 feet of the left wing was severed.
25:29The cable controlling the slats
25:31was sliced in two
25:32when the wing hit the light pole.
25:37Based on where the cable was cut,
25:39investigators can tell
25:40whether the slats and flaps
25:42were extended or retracted.
25:52It severed two cables,
25:54and if you lined up those two severed ends,
25:57it corresponded with the slats
26:00being in the full retracted position.
26:04It looks increasingly likely
26:06that the crew never extended their flaps.
26:09only the damaged flight data recorder
26:14can verify this.
26:21Fortunately, technicians have finally been able
26:23to rescue all its data.
26:26A digital history of Flight 255's performance
26:30until the moment of impact.
26:31I knew that if we had a good recorder,
26:37we were going to get data back.
26:39The flight data recorders in combination
26:41give you that time history
26:43that goes together with the physical evidence
26:46or physical damage.
26:49As expected,
26:50the FDR confirms what the evidence
26:52has been showing investigators.
26:54flight data recorders in the flight
26:59Flight data recorders told us
27:01that the flaps and slats
27:03had not been extended.
27:09It's a major breakthrough.
27:12Drake now knows what brought down Flight 255.
27:15But the flight data recorder
27:17doesn't answer a more troubling question.
27:19So, why weren't the flaps deployed?
27:23For some reason,
27:24a seasoned crew forgot
27:26one of the most basic steps
27:27involved in getting an airplane
27:29off the ground.
27:37Two months after the crash,
27:41Northwest Airlines Flight 255's
27:43sole survivor,
27:44Cecilia Sheehan,
27:45is released from hospital.
27:47We can't be sure
27:48why the little girl survived.
27:51She's a very little girl
27:53buckled into a big seat.
27:55And she was more protected
27:56than adults
27:58that might have been
27:58sitting around her.
28:01But she was very lucky.
28:03Jack Drake needs to know
28:05what contributed
28:05to the death of her family
28:07and all the other victims.
28:11He finds an important clue
28:13on the cockpit voice recorder.
28:14It shows that the last-minute
28:17runway change
28:18caused confusion
28:19in the cockpit.
28:21Once the aircraft
28:22began to taxi...
28:27Locker than hell out there.
28:29Northwest 255.
28:30No exit at Charlie Runway.
28:32Three center.
28:33Other activities
28:34were introduced
28:35that had the potential
28:37to cause distractions.
28:39Did he say three center?
28:42Three center, yeah.
28:43That's why I was thinking
28:43we had to go out of the way.
28:45I was thinking two-one.
28:47Well, they made a wrong turn,
28:49which might have been confusing
28:50because they had to go
28:52a different route.
28:53Where's Charlie at?
28:58Right at the end of this ramp.
29:00I think Charlie was...
29:01No, it is Charlie.
29:03You sure?
29:03No, thanks.
29:08The crew got lost
29:10on the way
29:10to runway 3C.
29:12Ground,
29:13Northwest 255.
29:15I guess we went by Charlie.
29:17We're going to three center-right.
29:19Northwest 255.
29:20Affirmative.
29:21Make a left turn
29:22at Fox Drive.
29:29They finally got to the runway
29:3145 minutes late.
29:35Ladies and gentlemen,
29:36we're currently number one
29:37for departure.
29:38Should be rolling
29:39in a couple of minutes.
29:41Light attendants,
29:42be seated.
29:47But Jack Drake
29:49finds something missing
29:50on the CVR.
29:52Come on.
29:53It seems the crew
29:54overlooked a very important step.
29:56We're okay for that
29:57center runway, aren't we?
29:59Damn.
30:02Before they got lost,
30:04the crew of Flight 255
30:05performed a number
30:06of checklists.
30:08But possibly due
30:09to the confusion
30:09of the runway change,
30:11they seem to have
30:12completely neglected
30:13the taxi checklist.
30:16They apparently
30:17didn't consider
30:17the checklist,
30:19and key in the checklist
30:20is the configuration
30:21of the aircraft
30:22for departure.
30:24And the flight data recorder
30:25showed that was never done.
30:26There are hundreds
30:29of small steps
30:30for a crew to take
30:31to get a passenger jet
30:32off the ground.
30:34Most of them
30:35are covered by checklists.
30:37The checklist
30:38is a means
30:39by which you ensure
30:41that important items
30:42are positioned
30:44or done properly.
30:45Transpond.
30:46Instead of doing it
30:47by memory
30:47and having the possibility
30:49of a lapse of memory,
30:52flight crews use
30:54a very rigorous
30:55and regimented procedure
30:57of following the checklist.
30:59Verify that each switch,
31:02each dial,
31:02each lever
31:03is in the proper position
31:04before taking the runway
31:05for departure.
31:07The first item
31:09on the taxi checklist
31:10is flaps.
31:13One of the things
31:14that would have been included
31:15in their checklist
31:16was to configure
31:18the slats and flaps
31:19for low-speed flight.
31:20But because they didn't
31:22run the checklist,
31:23the crew never set
31:24their flaps
31:25to the take-off position.
31:26I think Charlie was...
31:27No, it is Charlie.
31:29You sure?
31:32I think so.
31:35They hadn't done
31:36this checklist
31:37at the time
31:38they normally would,
31:39and as the activities
31:40piled up
31:41that were potential
31:43distractions,
31:44they were further
31:44and further away
31:45from the point
31:46at which they would
31:47normally perform
31:48that function.
31:48their mindset
31:49was probably
31:50that they had
31:51completed it.
31:54The pilots got
31:56an indication
31:56that their plane
31:57wasn't properly configured.
32:03During take-off,
32:04they couldn't activate
32:05the auto-throttle
32:06because their computer
32:07wasn't in take-off mode.
32:10Another step
32:10covered by the taxi checklist.
32:12Won't stay on.
32:15TCI's on set.
32:16This should have
32:19alerted them
32:20that they didn't
32:20perform the checklist.
32:22If it had occurred
32:23to them at that point
32:24that we might have
32:25missed something else
32:26on the checklist,
32:28that could have led
32:29to a rejected take-off.
32:33They are on now.
32:36100 knots.
32:38Okay.
32:38Apparently that
32:40didn't happen
32:42and so the take-off
32:43was continued.
32:44With disastrous results.
32:55An alarm
32:56should have sounded
32:57when the pilots
32:58tried to take-off
32:58with their flaps retracted.
33:01But for some reason,
33:02investigators can't hear it
33:03on the cockpit voice recorder.
33:05When it activates,
33:08it alerts the crew
33:09that the aircraft
33:10is not in a configuration
33:11that's safe for take-off.
33:14Maybe it went off
33:15or we just can't hear it.
33:20The investigation team
33:21is determined
33:22to find out
33:23why the take-off warning
33:24didn't sound.
33:26Technicians analyze
33:27the cockpit voice recorder
33:28for more clues
33:29and they find
33:31something unusual.
33:34They picked up
33:36some enunciations
33:37on the CVR
33:38that were not correct.
33:41Stall.
33:43Stall.
33:44This warning
33:45is alerting the crew
33:46that the plane
33:46is about to stall.
33:48But it should be coming
33:49from two speakers
33:50in the cockpit.
33:53Stall.
33:55Technicians notice
33:56it's only coming
33:57from one.
33:59Stall.
33:59Stall.
34:01Stall.
34:02As the airplane
34:02lifted off,
34:03there was a stall warning
34:04and it has a typical
34:07characteristic of a sound
34:08like stall all
34:09because there are
34:11two enunciations
34:12and the purpose of that
34:13is to provide redundancy.
34:15But that redundancy
34:16wasn't there.
34:17We had a single stall.
34:20I went to an MD-80
34:22sitting on the ramp
34:23at Detroit
34:24and a captain
34:26took us through
34:27the process
34:28of checking out
34:29to demonstrate
34:30those different sounds.
34:32Let's start
34:33with the config warning.
34:35The takeoff configuration warning
34:37is what would have
34:38alerted them
34:39about the flaps and slats.
34:41Flaps.
34:42Slats.
34:43Flaps.
34:45Can we get the stall warning
34:46sound?
34:47He activated the stall warning
34:54system by a test switch
34:55and it said stall all.
35:00The voice on the left channel
35:01is slightly different
35:02from the voice on the right
35:03as it should be.
35:05But that's not what Clark
35:07heard on flight 255's
35:08voice recorder.
35:09Can you make it sound
35:11like this?
35:14Stall.
35:16Stall.
35:17To get a singular stall
35:18he had to pull power
35:20to one side
35:21or the other.
35:22And one way
35:23he demonstrated that
35:24is he pulled
35:24the P-40 circuit breaker.
35:26A circuit breaker
35:27is the electrical switch
35:29that protects the circuit
35:30from damage
35:30caused by overload.
35:33The P-40 circuit breaker
35:34is an important one
35:35in this investigation.
35:36It handled both
35:38the failed takeoff warning
35:40and the stall warning
35:41systems.
35:42What struck me was
35:43he said
35:44I hear people doing it
35:46I of course
35:47don't do it myself
35:48but let me show you how
35:49and he reached around
35:50behind him
35:51around behind the seat
35:53and down low
35:54and pulled the P-40
35:55circuit breaker
35:56without looking.
35:58And then when he ran
35:59the stall warning system
36:00we got the singular stall.
36:03Stall.
36:05Stall.
36:06It's a major clue.
36:09Clark could only reproduce
36:10the strange sounding
36:11stall warning
36:12by pulling the same
36:13circuit breaker
36:14that's connected
36:14to the takeoff warning.
36:16This tells investigators
36:18that the breaker
36:19was tripped
36:19when flight 255
36:21tried to take off.
36:23Then John Clark
36:25notices something else
36:26about the P-40
36:27circuit breaker.
36:28You could see
36:29smudge marks
36:30around the decals
36:31on each side
36:32of the circuit breaker.
36:34It looked like
36:34finger marks
36:35where oil had built up
36:36and dirt
36:36and grime
36:37over the years
36:38so it told me
36:39that that circuit breaker
36:40was being used routinely
36:42by a lot of pilots.
36:47Can you tell me
36:48why that is so worn?
36:50It turned out
36:51that the takeoff
36:52configuration warning
36:53could be a nuisance
36:54to pilots.
36:57If you're doing
36:58a single engine taxi
36:59you have to push
36:59the throttle up further
37:00to get a power
37:01to taxi
37:02and you're set off
37:04the takeoff warning system
37:05and so they would pull
37:06the circuit breaker
37:06to silence it.
37:11It's irritating.
37:13It's a warning.
37:14It's meant to alert you
37:15and if it's going off
37:17routinely all the time
37:18it gets on their nerves
37:21and so apparently
37:25pilots were routinely
37:26silencing those takeoff warnings.
37:28investigators suspect
37:34that the crew
37:35of flight 255
37:36tripped the breaker
37:37to avoid the irritating
37:38takeoff warning
37:39and then
37:41with the added delay
37:42from the runway change
37:43and the impending storm
37:45they proceeded
37:47to take off
37:47without doing
37:48the taxi checklist.
37:49That might explain
37:53why the alarm
37:54didn't sound
37:54when they tried
37:55to takeoff
37:55with their flaps
37:56retracted.
37:57We don't know
37:58if the pilot
37:59did pull that circuit breaker
38:01on that particular flight.
38:02There was certainly
38:03one error
38:04and the potential
38:05for two.
38:06I think that the
38:06extensive use
38:07of the circuit breaker
38:08because of the smudge
38:09marks around the circuit breaker
38:10and the pilot's statements
38:11I think it's highly likely
38:12that he did.
38:13It appears
38:18the downing
38:19of flight 255
38:20was caused
38:21by pilot error.
38:27Now investigators
38:28can accurately
38:29piece together
38:29what happened
38:30that night in Detroit.
38:33But it would take
38:34another shocking accident
38:35for the airline industry
38:37to learn its lesson.
38:43Jack Drake's team
38:46has discovered
38:46what caused
38:47the crash
38:48of flight 255
38:49but cannot prevent
38:52it from happening again.
38:54One year later
38:55in Dallas
38:55Delta flight 1141
38:57tried to take off
38:59without their flaps
38:59extended.
39:01The investigators
39:03who had been working
39:04on the Northwest crash
39:05are stunned.
39:06I was very frustrated
39:08to learn
39:09that another airline
39:10had done the same thing
39:12in a different aircraft
39:13type about a year later.
39:15The Delta crash
39:16would uncover
39:17potentially deadly flaws
39:18in the checklists
39:21commercial pilots
39:22are trained to follow.
39:27The Delta
39:28and Northwest crashes
39:30killed 170 people
39:32and had eerily
39:34similar causes.
39:36In both disasters
39:37the workload
39:38in the cockpit increased.
39:40Jesus.
39:41Look at this.
39:42Northwest 255
39:44now exited
39:45Charlie runway.
39:46You know to hear
39:46pretty quick
39:47you won't have it
39:47bottled that.
39:49And in both
39:50the pilots
39:50failed to perform
39:51vital elements
39:52of their checklists.
39:55It is very unusual
39:57for a crew
39:57to not perform
39:59a checklist.
39:59They have done it
40:00hundreds upon
40:01hundreds of times.
40:02Brakes,
40:04windshield heat
40:05is on,
40:07cabin pressure controller
40:08is checked.
40:09The normal procedures
40:10were a little bit
40:12out of the norm
40:13and as a result
40:14it got overlooked.
40:16To prevent this
40:17from happening again
40:18aviation officials
40:20turn to a government
40:21agency that knows
40:22the importance
40:23of clear procedures.
40:25Four, three,
40:27two, one.
40:31NASA.
40:32Jack Drake and his team
40:39wanted the US
40:40space agency
40:41to help create
40:42checklists that
40:42decrease the odds
40:43of items being skipped.
40:46Asaf Deghani
40:47was a research scientist
40:48working with NASA.
40:51After the accident
40:53he took on the project
40:54of improving
40:54a flight crew's
40:55pre-take-off procedure.
40:56We looked for any
40:58research that was
40:59done on checklists
41:00or procedures
41:01in general
41:02and in fact
41:03we couldn't find
41:04anything.
41:06So Deghani
41:07had to start
41:08from scratch
41:09but there are
41:10dozens of different
41:11checklists to examine.
41:16Most of the ones
41:17on flight 255
41:18were printed
41:18on a single card.
41:21They listed the tasks
41:23the crew had to
41:24carry out
41:24but didn't give them
41:25a way to keep track
41:26of what was
41:27and what wasn't
41:28done.
41:30At the time
41:31of the Northwest
41:31crash
41:32there were several
41:33types of mechanical
41:34checklists in use.
41:36The US Air Force
41:37used a scrolling
41:38checklist.
41:39Once a checklist
41:40item is completed
41:41the pilot scrolls
41:43to the next one.
41:45American Airlines
41:46used a system
41:46that allowed pilots
41:47to cover up
41:48completed items
41:49with a plastic slide
41:50so only the
41:51non-completed items
41:52would be displayed.
41:55Asaf Deghani
41:59set out
41:59to see first-hand
42:00how pilots
42:01were using
42:01checklists.
42:03He wanted
42:04to make it
42:04less likely
42:05for them
42:05to make mistakes.
42:08He sat
42:09in cockpits
42:10and observed
42:1042 different
42:11crews in action.
42:14Deghani concluded
42:15that many
42:16checklists
42:16were badly
42:17designed.
42:17There's a certain
42:20flow by which
42:21you go about
42:22checking things
42:23and the idea
42:24is to prevent
42:24the case
42:25where you're
42:25doing one thing
42:26here,
42:26one thing there.
42:29Checklists
42:30should have
42:30a certain flow
42:31which is a
42:31logical flow
42:32and not one
42:33which is kind
42:34of random.
42:38Deghani also
42:39found a much
42:40more serious
42:40problem with
42:41checklists.
42:43If pilots
42:43are interrupted
42:44they sometimes
42:45forget where
42:46they left off.
42:50There's many
42:51cases where
42:52people would
42:52do A,
42:53B,
42:53C,
42:53D,
42:54E,
42:55an air
42:55traffic call
42:55would come
42:56and have
42:56to respond
42:57to it
42:57and that's
42:58an interrupt.
42:59Northwest 255
43:01now exited
43:01Charlie Runway
43:023 Center.
43:03Yeah.
43:05They would go
43:06back to the
43:06checklist and
43:08skip a certain
43:08item and continue
43:09on the list
43:10assuming that the
43:11whole list was
43:12done.
43:12People were
43:13very concerned
43:13about that
43:14to ensure
43:17no steps
43:18are missed
43:18airlines train
43:19their pilots
43:20to return to
43:21the top of a
43:21checklist following
43:22the interruption
43:23and start over.
43:25Again,
43:26Asaf Deghani
43:27sees a problem.
43:30And we found
43:31that if checklists
43:32are very, very
43:33long and meticulous
43:34that's overburdening
43:36the crew
43:36and they sometimes
43:37would not want
43:38to start again
43:38from the beginning.
43:40To address
43:41the problem
43:42Deghani suggests
43:43changes across
43:44the airline industry.
43:49One of our
43:50recommendations
43:50from the study
43:51is to try to
43:52take long checklists
43:53and chunk them
43:54to small pieces
43:55so that if an
43:56interruption happens
43:57then doing another
43:59four or five items
44:00it's not a big effort
44:02as opposed to doing
44:0220.
44:04Deghani even
44:05made recommendations
44:06about the typeface
44:07that airlines use
44:08so they can be more
44:09easily read by pilots.
44:13Perhaps the biggest
44:14advance to checklists
44:15is the move
44:16from paper
44:16to computers.
44:18Since at the time
44:19computer technology
44:20was coming into
44:21the cockpit
44:21it made a lot of sense
44:23to think about
44:24electronic checklist.
44:27Today Deghani
44:28and his team
44:29are studying
44:29smart checklists
44:30that keep track
44:31of checked items.
44:33They provide pilots
44:34with a visual indication
44:35of where they are
44:36on the list
44:36and in some cases
44:38verify that the task
44:39has been correctly
44:40carried out.
44:42Electronic checklist
44:43shows you
44:44which item
44:45was completed
44:45and which item
44:46was not.
44:52Computerized
44:53checklists
44:53are now slowly
44:54making their way
44:55into the cockpits
44:55of commercial airplanes.
44:57They make it
44:58far less likely
44:59that an accident
45:00like Northwest 255
45:02could happen again.
45:04The FAA
45:05also ordered
45:06a modification
45:07to the alarm system
45:08of all commercial
45:09jetliners
45:10to prevent
45:10nuisance alarms.
45:12The takeoff warning
45:13was redesigned
45:14so it could not sound
45:15unless the plane
45:16was actually taking off.
45:22Jack Drake
45:23went on to investigate
45:24hundreds of accidents
45:25over a 26-year career
45:27with the NTSB.
45:29The crash of Flight 255
45:31taught him
45:31a valuable lesson.
45:34This one is
45:35a worldwide example
45:37of the importance
45:38of following checklists
45:40and configuration
45:41being completed correctly
45:43on every takeoff.
45:45And so it became
45:46something that was
45:47a part of the training
45:48curriculum
45:49in virtually every airline
45:50around the world.
45:51The case of Northwest 255
45:52is no different.
45:53There's a series
45:54of events,
45:55runway change,
45:56task saturation,
45:57an overlooked checklist,
45:59a failed takeoff warning system.
46:01Put all of those together,
46:03those links in a chain,
46:05and you end up
46:05with the accident.
46:06If you were to break
46:08any one of those links,
46:10the accident
46:10wouldn't have happened.
46:11Flight 255 will also
46:15be remembered
46:16for its lone survivor,
46:18Cecilia Sheehan.
46:20She's never spoken publicly
46:21about the death
46:22of her family.
46:25But she's stayed in touch
46:27with the people
46:27who rescued her that day.
46:29She's full of life
46:32and the conversations
46:33we have,
46:34it's more about,
46:34you know,
46:35her sports
46:35and her husband
46:37and her vacations.
46:38She just said
46:39maybe one day
46:39she'll come out
46:40and tell the world
46:41what Cecilia is doing.
46:43She's never spoken to her.