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On 8 January 2016, West Air Sweden Flight 294 crashes near Lake Akkajaure in Sweden during a cargo flight from Oslo to Tromsø, Norway, killing both crew members. A malfunction in an inertial reference unit produced erroneous attitude indications and mislead the crew into a dive.
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00:00A jetliner plummets to Earth in the Swedish Arctic.
00:09Mayday! Mayday! Mayday!
00:10Air Sweden 294!
00:13Bank angle!
00:14No! No!
00:16Bank angle!
00:20A deep crater reveals an aircraft in an astonishing descent.
00:25It's just far out of bounds with the way we normally fly the airplane.
00:29Investigators are shocked by what they find.
00:32That can't be what the plane was doing.
00:34I flew the jet for 10 years and never saw anything even remotely like this.
00:37As the evidence paints a terrifying picture of chaos.
00:41Please!
00:42I don't know. I don't see anything.
00:43And confusion.
00:45If you get past a certain point, that confusion can become terminal.
00:49Why did he let the captain fly the plane into the ground?
00:58I don't see anything.
01:04I'm waiting for you.
01:05You have to go.
01:06I don't know.
01:07I don't know.
01:0933,000 feet above the border between Norway and Sweden,
01:20a CRJ-200 jet cruises on autopilot during a late-night mail run
01:26for one of Sweden's largest cargo companies, West Air Sweden.
01:30We are approaching Bodo, where the outside air temperature is a balmy minus 61 Celsius.
01:38Fuel?
01:38The 42-year-old Spanish captain has more than 3,300 hours of flight time.
01:44Minus 30, a little good.
01:47His French first officer is 33, with a similar number of flight hours.
01:53Sweden 294, clear direct to Varmann.
01:57Expect a circling approach to runway 01 at Tromso.
02:02Roger, circling approach for runway 01.
02:05Air Sweden 294.
02:06The experienced flight crew took off from Oslo, Norway, just after 11 o'clock,
02:13for a one-and-a-half-hour hop to Tromso, high in the Norwegian Arctic.
02:20The cargo jet is carrying about four-and-a-half tons of mail to the remote northern community.
02:26The CRJ-200 crosses into Swedish airspace as it heads further and further north.
02:34Sean Pruchnicki is a pilot who flew the CRJ-200.
02:41I'd like the airplane because it has all the bells and whistles.
02:45It's just as sophisticated as any of the larger jets.
02:48The aircraft itself is very fast.
02:49It's a very sleek airplane.
02:51So it's a lot of fun to fly.
02:53Ready for the approach breaker?
02:58Let's do it.
02:58ILS approach to runway 01, inbound heading 009.
03:09It's been a routine flight, and the plane is expected to land in Tromso in about 30 minutes.
03:15Climb and turn right.
03:16Acknowledged.
03:17And according to us, ATIS, we can expect light wind and zero.
03:26What the hell?
03:27Suddenly, the captain sees his plane is in a steep climb.
03:32He pushes the nose down.
03:36What?
03:39What?
03:47The pilots can no longer make sense of what the plane is doing.
04:17Mayday, mayday, mayday, F-394, mayday, mayday, mayday.
04:23F-394, understood, mayday.
04:25What is the nature of your emergency, please?
04:27The plane loses almost 10,000 feet of altitude
04:30and speeds towards the ground at more than 450 miles an hour.
04:45We need to climb.
04:47Come on, we need to climb.
04:48Yes, yes, we need to climb.
04:49Come on, go, go.
04:50No, continue right.
04:52Continue right.
04:53Okay, the meat.
04:54Come on, help me.
04:55Help me, please.
04:56I don't know.
04:57I don't see anything.
04:59At 8,800 feet, flight 294 falls below radar range.
05:06Good God.
05:09Look, look.
05:12West Air Sweden flight 294 hits the ground at almost 600 miles an hour.
05:25The plane is obliterated.
05:31It takes three hours before rescue helicopters arrive.
05:34Even from the air, it's obvious the pilots could not have survived.
05:42The information we got from the rescue efforts was that the aircraft was found
05:49and also that the accident was most probably not at all survivable.
05:56The crash site is in one of the most desolate places on Earth.
06:14The accident location was in a flat valley in mountainous area.
06:19The site was, at the time, very cold, with temperatures down towards minus 25 degrees Celsius.
06:39The next day, a team of investigators from the Swedish Accident Investigation Authority,
06:44known as the SHK, arrives at the crash site.
06:49The team includes technical investigator Tony Arvidsson.
06:54This far north, they have a very short window to find clues as to what caused the sudden crash of flight 294.
07:03We only had daylight time for about three hours.
07:12Investigators waste no time, analyzing the wreckage to pinpoint the northbound plane's orientation as it crashed.
07:20That's the front of the plane.
07:23So, they were traveling east.
07:27Finding the four corners of the aircraft confirms the theory.
07:32The tail, the nose, the wingtips, the aircraft had impacted the ground in an easterly direction.
07:41But it's in the wrong place for a plane flying east.
07:49This is Arvidsson's first clue about the accident.
07:52The left wing is found in the south end of the crater, and the right wing is in the north end.
08:00For a plane traveling east, it should be the other way around.
08:03If they were coming in this way, and the left wing is over there,
08:09then they must have been upside down.
08:16The crash has also created a crater 20 feet deep.
08:28That tells investigators the plane hit the ground at tremendous speed.
08:33The position of the wreckage and the size of the crater paints a picture of a plane hitting the ground off course,
08:51upside down, and at a blazingly high speed.
08:54Incredibly, both of the plane's black boxes survived the crash.
09:03They're sent to France, where the data can be downloaded.
09:08Investigators hope the data will shed light on why the plane was so badly out of control.
09:13As they continue to scour the site, blackened mail from the cargo hold presents a grim possibility.
09:28We'd be looking at a fire, an explosion.
09:33A fire or explosion on board could explain why the plane became so badly out of control while cruising at 33,000 feet.
09:43The team gathers as much of the cargo debris for analysis as they can.
09:50Okay. Those two boxes and everything in here.
09:57Let's get it all swapped.
09:59They need to determine whether fire was a cause of the accident.
10:04So we send one ton of cargo to a fire expert.
10:13Elevator goes, along with all the control cables.
10:19This goes too.
10:21The team recovers a total of three and a half tons of wreckage.
10:27Mostly parts from the flight controls.
10:32We try to get as much as possible from the site.
10:36Before fierce winter weather sets in, investigators must abandon the site.
11:01They can only hope the cause of this crash lies somewhere in the pieces they're taking with them.
11:12Swedish investigators hope the Norwegian air traffic controller on duty the night of the crash of Flight 294
11:19can help explain why the pilots lost control of their plane at 33,000 feet.
11:24Okay, so the first sign of trouble was a mayday call at 1219.
11:31Mayday, mayday, mayday, F Sweden 294, mayday, mayday, mayday.
11:35294, understood mayday.
11:37What is the nature of your emergency, please?
11:40So no explanation for the mayday call?
11:43No, they never said.
11:44If it's just a mayday call like this one with not much specificity,
11:49then there's not much the controller can do other than try to discern what's happening and attempt to help.
11:54He was descending quickly and he started to veer east here.
11:58The radar data confirms what investigators observed at the crash site.
12:04Flight 294 was descending rapidly and veering east just seconds before it disappeared from the screen.
12:12And the return never split.
12:14No, just one blip all the way down.
12:16The radar shows only one return, meaning it didn't break into pieces in midair.
12:22If you have an airplane that came apart at altitude, you're going to see a lot of different radar returns.
12:27If you have one singular return and it doesn't advance forward very much,
12:30maybe one more hit and then it's gone, that indicates a dive intact.
12:36The investigators now know the pilots were struggling with a serious on-board emergency.
12:40Thanks for coming down.
12:41But still don't understand what could have caused such a catastrophic loss of control.
12:47In Stockholm, the team inspects the three and a half tons of wreckage for signs of a fatal mechanical failure.
12:57We're looking for a failure of any control surface.
13:04Ailerons, elevators, rudder.
13:07We need to check them all.
13:09An airplane has three primary flight control surfaces.
13:14Ailerons that control roll, elevators that control pitch, and a rudder that controls yaw.
13:24A broken flight control, like the elevators, could cause some problems.
13:29But this is the worst damage Arvidsson has ever seen.
13:33It's impossible for him to get any useful information about flight control surfaces.
13:41This tells me nothing.
13:44We want to make sure that the control surface is working properly, but it was too damaged.
13:50Investigators try to identify the pieces of wreckage based on serial numbers and other markings to make sure all the control surfaces were on the plane when it hit the ground.
14:02Left and right ailerons, both elevators, rudder.
14:14We have them all.
14:17We could find and identify all the control surfaces, which make it most probable that the aircraft was intact all the way down to impact.
14:30They rule out a serious mechanical failure and move on to another theory, that an on-board fire brought down the plane.
14:42Tests on flight 294's cargo don't offer investigators much more insight than the control surfaces.
14:50No sign of fire or explosion.
14:52The cargo was destroyed at impact.
14:57Not in an on-board fire.
14:59Searching for answers, the investigator in charge, Nicholas Seeger, turns to the flight data, now in from France and ready for analysis.
15:09The FDR data for us is really important to understand the course of events.
15:15It also helps us to calculate the trajectory of the aircraft.
15:20So they're cruising at 33,000 feet when suddenly they start to pitch way up.
15:28A plane normally changes pitch by about one degree per second.
15:33But in this case you had six degrees per second.
15:36So it was a really rapid change of pitch.
15:39Then the plane starts pitching down and starts rolling out of control.
15:47We can see this is not normal.
15:49When a plane pitches up, investigators would expect it to climb in altitude and its speed to slow.
16:08But that's not what the data from flight 294 shows.
16:11His airspeed indicator was not changing.
16:16Same with the altitude.
16:18The altitude should have showed a climb if this was good data.
16:21And it did not.
16:23That can't be what the plane was doing.
16:26Investigators must get to the bottom of the contradictory data
16:29before they can figure out what brought down West Air Sweden flight 294.
16:34We're going to have to go back and figure out exactly what was going on here.
16:42Investigators in Stockholm try to understand discrepancies in flight 294's flight data.
16:49Okay, so let's assume airspeed and altitude are correct.
16:55Yes?
16:56The plane's pitch data doesn't make sense.
16:59We made calculations to determine the real pitch of the aircraft during the event.
17:09The calculations point to an astounding conclusion.
17:13So, no pitch up at all?
17:17Not that we can tell.
17:19The calculations indicated that the pitch was actually going down after the start of the event.
17:29Right here, the data shows a steep pitch up,
17:33but the plane flies level and then pitches down.
17:43Not up.
17:49What the hell?
17:51It seems the captain thought the plane was pitching up
17:54when it was actually flying straight and level.
17:59The discovery leads investigators to a disturbing question.
18:09Were the pilots responding to an emergency
18:12that didn't actually exist?
18:15If they aren't actually pitching up,
18:18why are they pushing the nose down?
18:20The indication that the ADI,
18:25the attitude deviation indicator on the captain's side,
18:27had suddenly shown a 30-degree pitch up
18:30is about the only thing that even comes close to making sense
18:32for why this crew would take a perfectly good airplane and do a dive.
18:37Investigators soon discover that it's not just the pitch data that's off.
18:40Right here, heading and roll are wonky, too.
18:46You see that?
18:47Yeah.
18:48That tells us something.
18:50Yeah.
18:51It's another valuable clue.
18:53When we looked at the FDR data,
18:56we could see four parameters
18:57that were not consistent with the other parameters.
19:02And those were the pitch, the roll, the heading and the ground speed.
19:07All four parameters come from what's called an inertial reference unit, or IRU.
19:13It's made up of gyroscopes that provide information to the cockpit displays
19:18and to the flight data recorder.
19:20There are two IRUs, one for each pilot's display.
19:25The FDR gets its data from the captain's side, IRU.
19:31Investigators study the plane's manuals and electrical drawings.
19:35We found that the IRU-1 was sending the attitude signal
19:42to the flight data recorder and the primary flight display number one.
19:47It's an important discovery.
19:49The captain's display and the flight data recorder
19:52both get their pitch data from the same source.
19:57Now this is what the captain was seeing.
20:02Investigators are coming to a troubling conclusion.
20:05The captain's instrument was telling him the plane was pitching up
20:08when it was still flying level.
20:12And that it was rolling to the right
20:14when it was actually rolling left.
20:17The automation is telling him, point the nose down,
20:20and he's trying to follow this.
20:22Unfortunately, it's erroneous information,
20:24and that eventually leads to a loss of control of the aircraft.
20:28I flew the jet for 10 years.
20:29I never saw anything even remotely like this.
20:31What the hell?
20:36It's now clear the pilot was receiving bad information from a faulty IRU.
20:42Is it possible the first officer was, too?
20:46The FO's instrument has its own gyro.
20:50Investigators learned that IRU-1 was only feeding the captain's instrument.
20:54A second IRU feeds the first officer's display
20:58and is not recorded by the flight data recorder.
21:02So is it possible that both sides could have failed?
21:07If the first officer's instrument was correct,
21:10he should have seen that the plane was flying straight and level.
21:13So why did he allow the captain to push the plane into a high-speed dive?
21:20To find out, the team recreates the flight in a simulation
21:23based on the data from IRU-1.
21:27OK, start the animation.
21:29It paints an almost incomprehensible picture.
21:32Three seconds after his instrument shows a pitch up,
21:37he pushes the nose down.
21:39The pilots tried to solve the problem
21:43by pushing the elevators to nose down.
21:47When the captain pushes the nose down,
21:50his ADI continues to show a pitch up,
21:53so he keeps pushing the plane into a steeper and steeper dive.
21:58And they begin to roll to the left.
22:02The plane continues to roll until it's on its back.
22:05Eventually, they do reach a speed of 508 knots.
22:13It is pretty much incredible that the aircraft
22:15did not start breaking up because of the aerodynamic forces,
22:18but any control movement at all is going to rip the tail off
22:21or going to rip the control surfaces off.
22:23Flight 294 hits the ground inverted
22:26at a speed of almost 600 miles an hour.
22:29The speed with which this airplane went from stable flight
22:34to a smoking hole, a crater, literally,
22:37is just astounding because it involves a descent rate
22:40at one point of over 20,000 feet per minute.
22:43That's a straight vertical dive at almost speed of sound.
22:46It means that whatever happened, happened extremely rapidly.
22:51Investigators can now see what happened,
22:52but they still don't understand why the failure
22:55of a single instrument led to such a sudden
22:58and catastrophic crash.
23:00How do you go from level flight at 33,000 feet
23:04to 1,000 kilometers per hour impact in...
23:09What?
23:11One minute, 20 seconds.
23:17Investigators are stumped.
23:18The failure of one single instrument
23:24in a triple redundant system
23:27should allow the crew or the operations
23:31to actually cope with this situation.
23:37To better understand how the pilots
23:39were interpreting flight data,
23:41investigators now turned to the cockpit voice recording
23:44of Flight 294.
23:46Let's hear what was happening up there.
23:48Ready for the approach, please?
23:50Let's do it.
23:52Investigators hear no signs of trouble
23:53in the minutes leading to the accident, until...
23:57Okay, now this is where the trouble starts.
24:02What the hell?
24:08What?
24:11What?
24:12What?
24:12They're barely talking to each other.
24:24We were a little bit surprised
24:27that there were no communication
24:30for the first 10 to 12 seconds
24:34after the problem started.
24:37For some reason, the two pilots
24:42never discussed the unusual pitch.
24:45Come on, help me.
24:46Help me.
24:47Help me.
24:48Yes, I'm trying.
24:49I'm trying.
24:49Don't lift.
24:50Don't lift.
24:51Or how to troubleshoot the issue.
24:54Bank angle.
24:55Wait a minute, stop.
24:57Bank angle.
24:57Bank angle.
24:58Bank angle.
24:59Bank angle.
25:00When did this start?
25:0313 seconds after the trouble started.
25:0540 degrees.
25:09Exactly when it should come up.
25:12The warning is programmed to sound
25:14when the plane's bank angle gets to 40 degrees,
25:17which is precisely when it sounded on flight 294.
25:22In a CRJ-200,
25:24the bank angle display and warning
25:26get data from the IRU designated
25:28to the first officer's side.
25:30Hearing the bank angle call-outs
25:34gives the investigation some vital information.
25:38In Earth Hill Reference,
25:39unit number two was working as it should be.
25:42The first officer was getting good information.
25:46The discovery confirms
25:48the first officer should have known
25:49the plane was never pitching up in the first place.
25:52So why did he let the captain
25:55fly the plane into the ground?
26:00We need to climb and turn right.
26:02Acknowledged.
26:03Investigators have a new mystery to solve.
26:06And according to last eight tests,
26:08we can expect light wind and zero...
26:11What the hell?
26:15When the captain of flight 294
26:18plunges into a deadly dive...
26:19Why didn't the first officer intervene?
26:29As investigators look at the FDR data,
26:32they make an important discovery.
26:35The pilots both received
26:37what's called a miscompare warning.
26:39The warning is shown on both displays
26:42when there's a mismatched reading between them.
26:45In this case, PIT for pitch.
26:47Investigators now know that while the captain
26:50saw a sudden 30-degree pitch-up
26:53and the co-pilots saw a perfectly level aircraft,
26:57both saw the pitch discrepancy warning.
26:59It's a puzzling find
27:00because pilots are trained
27:02how to react to the warning.
27:03You would hope that communication-wise,
27:16you'd be able to verbalize,
27:17I have what appears to be an extreme pitch-up.
27:20What are you showing on your side?
27:24I'm showing a pitch-up.
27:26In the event of a discrepancy,
27:32pilots should check a third standby instrument
27:34to determine which side is wrong
27:36and switch the faulty instrument
27:38to the working IRU.
27:43Looks like my side's bad.
27:45Switching to IR2 now.
27:46Ideally, what we refer to
27:52as a standby attitude indicator
27:54could have kind of broken the tie.
27:56In other words,
27:57we have three sources of information
27:58and the best two out of three
28:01is what you're trained to go with.
28:04All right.
28:05Let's see what they say next.
28:07But when investigators listen to the CVR...
28:10We need to climb.
28:11Come on, we need to climb.
28:12Yes, yes, we need to climb.
28:13Go left.
28:14Go left.
28:14They don't hear that kind of conversation.
28:19Continue, Blake.
28:21Instead, they hear the sound of a crew
28:23that can't figure out
28:24what's happening to their plane
28:25or how to correct the problem.
28:28Come on, help me.
28:29Help me, please.
28:30I don't know.
28:31I don't see anything.
28:34And what that tells us
28:36is that the crew members
28:37are both very mentally consumed
28:39with looking at their primary flight display,
28:41trying to figure out actually what is going on.
28:43What is the real position of the aircraft in space?
28:47It's a troubling revelation.
28:49What the hell?
28:53Seeger decides they need to see
28:55exactly what the pilots experienced
28:57when the instruments began to fail.
29:00They book time in a CRJ simulator.
29:02They fly the same route as flight 294
29:12and program a fault into the left side IRU.
29:15In the simulator, we could observe
29:20the two primary flying displays
29:22and we could also see
29:26that everything was working according to design.
29:31There it is.
29:33Freeze it there, please.
29:35When the captain's ADI shows a sudden climb,
29:38the miscompare warning comes on,
29:41telling the captain and first officer
29:42they're seeing different pitch readings.
29:46Okay.
29:47All right, let's pick it up here.
29:50Then, they make a new discovery.
29:53And now we've got the declutter mode kicking in.
29:57Freeze it there, please.
29:58All right.
30:07When a pilot's ADI reaches extreme pitch or roll values,
30:11it goes into what's called declutter mode.
30:14All non-essential information disappears
30:16and red arrows tell the pilots which direction to fly.
30:20The declutter mode is to help the pilot
30:24focusing on the most important things.
30:29But that's not the only insight
30:31the flight simulator provides the investigation.
30:35And guess what disappears in declutter mode?
30:39Investigators learn that in declutter mode,
30:42the PIT discrepancy warning
30:44alerting the pilots of mismatched displays
30:46also disappears.
30:49Four seconds after that warning appeared,
30:52it disappears for good.
30:54It's not enough time for the captain
30:56to register the problem.
30:59What the hell?
31:00And as a result,
31:01he instinctively pushes the nose down,
31:04not realizing he's putting the plane into a dive.
31:10Soon, the first officer's gauge
31:12also enters declutter mode.
31:14But in almost the opposite configuration
31:20of the captain's display.
31:25Come up!
31:28Now, neither one of them has a discrepancy warning.
31:33This is potentially problematic
31:35because the crew is still trying to figure out
31:37what's going on
31:38in addition to following the erroneous automation commands.
31:41So this box,
31:42what was telling them what the problem was,
31:44actually disappears
31:45when the situation becomes even more dire.
31:49As the pilots were struggling
31:51to regain control of their plane...
31:53Yes, I'm trying.
31:54I'm trying.
31:54Go left.
31:55Go left.
31:57Both were missing a vital piece of the puzzle,
32:00that their displays were showing different pitch angles.
32:04That's one bit of information
32:06that really should not have been removed
32:08when it goes to a decluttering function.
32:10That was the only cue that they really had
32:13that there was potentially a problem
32:15between both primary flight displays.
32:18Investigators now have a picture
32:20of what happened in the cockpit.
32:22We need to climb.
32:23Come on, we need to climb.
32:24Yes, yes, we need to climb.
32:25Go left.
32:26Go left.
32:26Go left.
32:26Continue right.
32:28Okay.
32:29But to figure out why the pilots couldn't tell
32:32if they were climbing or diving...
32:34Come on, help me.
32:36Help me, please.
32:36I don't know.
32:37I don't see anything.
32:40Investigators will need to take to the skies.
32:48Investigators fly an identical plane
32:50on the same route
32:51under the same moonless conditions
32:53to find out what the pilots of Flight 294
32:56could and couldn't see
32:57on the night of the accident.
33:00You could see lights.
33:02Maybe Ritson.
33:06And I can just see the horizon over there.
33:11We are approaching Budo.
33:13Even when flying at night time,
33:15there can still be visual cues
33:17that can help you understand
33:18the orientation of your aircraft.
33:21Things like you can still see
33:22a visible horizon sometimes
33:24when there are a lot of city lights.
33:26The test seems to be in vain,
33:29revealing nothing out of the ordinary.
33:31Okay, let's start the descent into Tromsel.
33:41Now I can't see anything out there.
33:44It was very, very difficult
33:48to discern the horizon
33:50during this flight
33:51when you had the cockpit illumination on.
33:54Investigators have made a major discovery.
34:06With the cockpit lights turned on,
34:08it would have been impossible
34:09for the pilots to see the lights below
34:11or the horizon.
34:13The pilots of 294
34:15would likely have depended entirely
34:17on their instruments for guidance.
34:20Instruments that show
34:21contradictory information.
34:23We need to climb.
34:25Come on, we need to climb.
34:26Yes, yes, we need to climb.
34:26Go left.
34:27Go left.
34:27Go left.
34:27Continue right.
34:29Continue right.
34:31When we can't see outside,
34:33we trust our instruments.
34:34But if your instrument
34:35is telling you something
34:36that is completely separate
34:37from what your body is telling you,
34:39it's not a matter of ignoring
34:40one or the other.
34:41It's a matter of verifying
34:43what the situation is.
34:44The discovery reveals
34:46a critical piece of the puzzle.
34:47Ready for the approach breather?
34:51Let's do it.
34:53After the captain of flight 294
34:55switches on the cockpit lights,
34:57According to last ATAS,
34:59we can expect...
35:00His display begins to indicate
35:02a substantial pitch upwards.
35:04What the hell?
35:05But glare inside the cockpit
35:07means the pilots
35:08can't see the horizon below.
35:10The captain can't tell
35:12if his plane is actually climbing or not.
35:14Had this happened earlier
35:16when they might have had
35:18some form of a visible horizon,
35:20it could have had
35:21an entirely different outcome
35:22and probably would have.
35:24He sees this,
35:26so his first reaction
35:27is to push his nose down.
35:31Seeger thinks the captain's response...
35:33Back now?
35:34Yes, I'm trying.
35:35I'm trying.
35:36...made it impossible
35:37for either pilot
35:38to make sense
35:39of the plane's movements.
35:40So, lift.
35:41Back angle.
35:42What are the adages
35:43that we have kind of instilled
35:45in commercial aviation
35:46and in military aviation
35:47is, in an emergency,
35:49order a cup of coffee first
35:50before you decide
35:51to do something.
35:52There are very few things
35:53in aviation that need
35:54an instantaneous physical response.
35:57In less than 30 seconds,
35:59the plane is upside down
36:00and diving.
36:01Back angle.
36:02Extreme negative G forces
36:04make the pilots feel weightless
36:06so they can't tell
36:07if they're climbing or descending.
36:08When faced with a negative G environment,
36:12it's disorienting
36:13for many reasons,
36:14one of which
36:15is that it actually
36:16affects your cognitive ability,
36:18so your ability
36:19to understand
36:20the situation
36:20that you're in.
36:25In just five seconds,
36:27his autopilot disconnects.
36:29He's faced
36:29with a 30-degree pitch-up
36:31and his instrument display changes.
36:35Back angle.
36:36Mayday, mayday, mayday.
36:38Air Sweden 294.
36:39Mayday, mayday, mayday, mayday.
36:40Investigators believe
36:41that the rapid-fire chain of events
36:43triggers what's known
36:44as the startle
36:45or surprise effect
36:46in both pilots.
36:48That surprise effect,
36:50together with the lack
36:52of communication
36:53between the pilots,
36:55can explain the difficulties
36:57there were to solve the problem.
37:00Back at you.
37:02Back at you.
37:02This is basically
37:03the environment
37:04that they found themselves in.
37:05going from extremely
37:06normal operations
37:08to extremely abnormal operations,
37:12basically within a split second.
37:15Back at you.
37:15Go left.
37:16No, continue right.
37:17Back at you.
37:18Continue right.
37:19Okay, the meat.
37:20Help me.
37:21In a lot of ways,
37:23this accident
37:24is kind of a perfect storm scenario.
37:26The fact that both crew members
37:28were looking away
37:29from their instruments
37:29as they were required to do,
37:31briefing the approach.
37:32the fact that the autopilot
37:34disconnected so quickly,
37:36the fact that
37:37the indication of pitch
37:38was so extreme.
37:41Come on, help me.
37:43Help me.
37:43Please.
37:44I don't know.
37:44I don't see anything.
37:46Investigators now believe
37:47they have pieced together
37:48what went so horribly wrong
37:50on Flight 294.
37:52No!
37:53No, no!
37:54But they still have
37:57one final question
37:58to answer.
38:02Ready for the approach briefing?
38:04Let's do it.
38:06The final minutes
38:08of Flight 294
38:09are now clear
38:10to investigators.
38:11ILS approach
38:12to runway 01,
38:13inbound heading 009.
38:16The approach briefing
38:17is interrupted
38:18when the captain
38:19notices a sudden climb.
38:20Light wind
38:21and zero.
38:24What the hell?
38:25The start of the event
38:27was a runaway
38:28on the left side
38:30pilot flying display
38:32showing an increasing pitch.
38:35But he has no idea
38:37what he's seeing
38:38is from a faulty
38:38inertial reference unit.
38:41The pitch warning disappears,
38:43the autopilot disconnects,
38:45and the captain
38:46pushes the nose down
38:47following instructions
38:48on his ADI.
38:49As the plane
38:51begins to dive,
38:53the pilots
38:53don't know
38:54their displays
38:54no longer match.
38:56What?
38:58What?
39:01And as they can't
39:02see the natural horizon
39:04outside,
39:05neither pilot
39:06can verify
39:06their actual attitude.
39:08As the plunging jet
39:10rapidly gains speed,
39:12negative G-forces
39:13make the pilots
39:14feel weightless.
39:16Flight 294
39:18rolls to the left
39:19until it banks
39:20upside down.
39:22It's possible
39:23that this occurred
39:24because now
39:25the first officer
39:25had grabbed the yoke
39:27to steady himself
39:28or to possibly
39:29try to contribute
39:30to solving the problem.
39:32Upside down
39:33and hurtling to earth,
39:34the first officer's display
39:36shows the plane
39:37in a nosedive
39:38and banking left.
39:39Come up!
39:41Bank ankle.
39:42But the captain
39:43sees the opposite,
39:44a plane climbing
39:45and rolling right.
39:47Come up!
39:48Bank ankle.
39:48His first officer's
39:49suggestions make no sense
39:51and the inverted G-forces
39:53make it almost impossible
39:54to think.
39:55Come on, help me.
39:57Help me.
39:57Bank ankle.
39:58Help me?
39:58Yes, I'm trying.
39:59I'm trying.
39:59Don't lift.
40:00Don't lift.
40:01Bank ankle.
40:02No.
40:03When you get sucked
40:05into a reality
40:06in the middle of the night
40:07like this
40:08that is not commissar
40:10with what's actually happening,
40:11in other words,
40:12it's an induced reality,
40:13then it begins
40:15to get confusing
40:15and if you get past
40:16a certain point,
40:17that confusion
40:18can become terminal.
40:20The plane is in a steep dive,
40:23nearly inverted,
40:24and traveling at speeds
40:25approaching 600 miles an hour.
40:28Once you get to that point,
40:30the mind pretty much checks out
40:32in terms of giving you
40:33good guidance
40:34on how to fly the airplane
40:35and after that point,
40:37there's just no recovering.
40:39We need to climb.
40:40Come on.
40:41Yes, yes, we need to climb.
40:42Don't lift.
40:43Don't lift.
40:43Oh, continue right.
40:45Bank ankle.
40:45Pull up.
40:46Continue right.
40:47Please, David.
40:48Come on, help me.
40:49Help me, please.
40:50I don't know.
40:51I don't see anything.
40:53Oh, God.
40:53Bank ankle.
40:54What?
40:54What?
40:55Bank ankle.
40:56Oh!
40:57Bank ankle.
40:58No!
40:59No, no!
41:0180 seconds
41:02from the first sign of trouble,
41:04the plane slams into the ground.
41:05There's no training that's typically provided
41:13to understand how to effectively recover
41:17from a situation such as this.
41:19The final question for investigators
41:22will be the most difficult to answer.
41:25Why did the inertial reference unit fail in the first place?
41:28With more than 9,000 identical units in service around the world,
41:36the answer is vitally important.
41:41The IRUs have been recovered from the crash site,
41:44but they're very badly damaged.
41:46The physical IRU was damaged beyond recognition,
41:54and we couldn't find out what caused the problem.
42:03Nothing.
42:05Without the device's memory cards,
42:08investigators are unable to determine the cause of the failure.
42:11We tried in every possible way,
42:16but we didn't have enough evidence to understand it.
42:22What the hell?
42:23Regardless of what caused it,
42:25the IRU's failure should not have caused an accident.
42:29There are backup instruments on board for precisely that reason.
42:34Redundancy is one of the keys to aviation safety,
42:37because not only do we need redundant pilots,
42:39because human beings can fail,
42:42but we need redundant instruments.
42:43We don't want to ever get in a situation
42:45where a single-point failure
42:46is going to cause you
42:48to not be able to fly the airplane safely.
42:54In their final report,
42:56investigators list the pilot's failure to communicate properly,
43:00the lack of information provided by the flight instruments
43:03about the failure,
43:04and the effect of negative G-loads on the crew
43:08as the main factors causing the accident.
43:12It's important to communicate really early
43:16when you've got a problem,
43:18so the other pilot can understand what's going on.
43:23The investigators recommend that airlines adopt standard call-outs
43:27for pilots to use in similar emergency situations,
43:30and that manufacturers improve the design of primary flight displays
43:35so that important error messages aren't removed in declutter modes.
43:41If you've got more than one crew member,
43:43and in almost all instances in airline flights you do,
43:46you need a procedure for immediately checking with each other
43:49and having standard call-outs
43:50so that you are coordinating your actions
43:52and coordinating your brains.
43:54Here we had one carbon-based brain
43:56making decisions that were incorrect
43:59and starting a slide into an accident sequence
44:01because there was no coordination with the other one.