- 7 months ago
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00:01Fierce winter weather...
00:03Ooh, really cold here.
00:06...wreaks havoc with three different flights...
00:09Almost instantly it was clear that that aircraft was not flying normally.
00:12V-1?
00:13...after a captain misses a step at take-off...
00:16Larry, we're going down, Larry!
00:18I know it!
00:21Unbelievable.
00:22...when pilots neglect icy wings...
00:24We're in a dive. We're in a dive.
00:26You never give up. You do what you gotta do to try to make it.
00:29And when crews misread warning signs...
00:37Investigators are faced with a conundrum.
00:39How could three modern aircraft end up with frozen wings?
00:59A heavy snowstorm blankets the U.S. capital.
01:14Planes at Washington's National Airport are grounded.
01:17The 74 passengers and five crew on board Air Florida Flight 90...
01:23...hoped to be in the air by now. But they're still at the gate.
01:29We should have rebooked when we saw the weather.
01:32We might still make it.
01:34Joe Stiley is a businessman and private pilot.
01:37He's traveling with his assistant, Nicky Felch.
01:42Everybody realized that it was one of those days.
01:44It was a snowy day. The chances of getting out were 50-50, maybe.
01:50Captain Larry Wheaton is in command of Flight 90.
01:5460 degrees in Tampa and we're stuck in a snowstorm.
01:56His first officer is a former Air Force pilot, 31-year-old Roger Pettit.
02:02Florida is home to both men.
02:06Airport crews work furiously to clear the runway.
02:12And after an hour and a quarter...
02:14Tower.
02:19Reopening now.
02:20Copy that.
02:22Okay! Showtime!
02:26Air Florida Flight 90 soon gets the green light from controllers.
02:31Palm 90, taxi into position.
02:33Captain, you ready for an immediate take-off?
02:35Palm 90.
02:38Today, First Officer Pettit will fly the Boeing 737.
02:41While Captain Wheaton monitors instruments.
02:48Whoa!
02:50Whoo!
02:52Really cold here.
02:53Real cold.
02:55To get airborne, the plane must reach 139 knots.
03:01God, look at that thing.
03:03The First Officer checks the power levels.
03:06That don't seem right.
03:07Does it?
03:09Is it?
03:10There's 80.
03:13Huh?
03:14Maybe it is right.
03:17120.
03:27B-1.
03:28When we got airborne, almost instantly it was clear that that aircraft was not flying normally.
03:38Air speed, low.
03:43Easy.
03:47Low.
03:48Forward.
03:49Forward.
03:51Up.
03:52Up.
03:53Forward.
03:54Forward.
03:55Up.
03:56Forward.
03:57Go on.
03:58Stay down.
03:59Keep your head down.
04:01No!
04:06Up.
04:07noches
04:12Larry!
04:13We're going down Larry!
04:14I know it!
04:15Up!
04:17Up!
04:19Up!
04:21Up!
04:22Up!
04:23Air Florida Flight 90 has plunged into Washington, D.C.'s Potomac River.
04:31Of the 79 people on board, only six escape the wreckage and make it to the surface.
04:44On the bridge, four people are dead and four more injured.
04:53News cameraman Chester Panzer arrives on the scene in time to cover rescue efforts.
05:00I started rolling and the first thing I saw was someone being loaded into an ambulance.
05:06The rest of the survivors are still trapped in the icy water.
05:10A fellow who was strapped into his seat right in front of us who couldn't get out because a bunch of cables and things like that had gotten around him and he was just wired in place there.
05:21And then I turned to Nicky and I said, I'm all broken up and I know I can't swim. My legs aren't working.
05:29The survivors won't last long in the freezing water.
05:37Flight attendant Kelly Duncan manages to reach the line.
05:41She was holding on and the helicopter was just flying her in.
05:50Joe Stiley does all he can to help Nicky and fellow passenger Priscilla Tirado.
05:55I had Priscilla in a kind of an arm lock on this side and I had Nicky on this side, but this arm wasn't working very well.
06:04And the helicopter began to pull us away into the water.
06:08I lost Nicky almost instantly because this whole arm just was dysfunctional.
06:13And I had Priscilla under that arm for about halfway across the river and we started running into the broken ice.
06:22At some point during that I lost my grip on Priscilla and left her laying there on the top of a block of ice.
06:29Joe is pulled to safety.
06:40The helicopter drops Priscilla a life ring, but she can't hang on.
06:45That's when it hit me that this woman was going to drown in front of me.
06:49She's in the open water and she's being pushed under the water by the helicopter wash.
06:53A bystander takes action.
06:58He didn't think about how cold the water was, didn't think what it would do to him.
07:04Lenny Skutnik saves Priscilla's life.
07:13Nicky is the last survivor pulled from the water.
07:1678 people have lost their lives in the tragic accident.
07:25Within hours investigators from the National Transportation Safety Board are on the job.
07:31Other aircraft did depart, which means that things were successful in other jetways.
07:38What was wrong with this particular aircraft that caused a crash?
07:42Early in the investigation, Air Florida's flight recorders are found.
07:50The data gives the team its first clues.
07:54It told us the altitude and the time.
07:57And so you knew how long it rolled down the runway before it lifted off.
08:02Takeoff was very slow.
08:04Flight 90 took 15 seconds longer than usual to get airborne.
08:07There's gotta be something about their engine power.
08:12V1?
08:14It didn't climb in a normal way.
08:16So obviously there was something wrong with the amount of power.
08:22In 1982, aircraft data recorders aren't sophisticated enough to pinpoint what was wrong with the engines.
08:28Voice is bad.
08:29Voice is bad.
08:31It's probably the worst time I've seen.
08:34Investigators now turn to the cockpit voice recordings.
08:38Can you see your wing tip?
08:40I got a little bit on mine.
08:42A little?
08:44This wing's got about a quarter to a half an inch on it.
08:47All the way.
08:49Wheaton and Pettit are heard discussing the removal of ice from the aircraft's wings.
08:54They pulled up in back of another aircraft, a DC-9, thinking that they might be able to warm up and blow off their aircraft.
09:03The captain maneuvers his plane into the exhaust stream of the plane ahead.
09:08It's an unconventional strategy to de-ice without losing the plane's place in the queue.
09:13But so far, McAdul has heard nothing that would explain the loss of engine power.
09:22Your throttles?
09:23Okay.
09:29Then, he hears something disturbing.
09:34Oh!
09:36God, look at that thing.
09:38The first officer thinks there's a problem with the plane's acceleration.
09:41That don't seem right.
09:44Does it?
09:46Yes, it is, there's 80.
09:48But the captain sees no cause for alarm.
09:51Huh?
09:52Maybe it is right.
09:54Despite the first officer's hesitation, the captain thinks the engine power is sufficient for takeoff.
10:00The team must now determine Flight 90's exact power levels.
10:04Come on, I've got an idea.
10:05The sound of the engines is recorded in the background on the cockpit voice recorder.
10:12The sound of Flight 90's engines should tell McAdul how much power they were generating.
10:16You ready to go?
10:17Yeah.
10:19Okay.
10:21Forward, forward.
10:23They eliminate the pilot's voices and isolate the engine sounds.
10:28Jet engines contain turbines, which make different sounds depending on how quickly they're spinning.
10:33When the engine needs more power, the turbine spins faster and the pitch of the sound changes.
10:40Can you turn that up a bit?
10:44The results are dramatic.
10:48The sound analysis indicated that the engines were running at a speed that would produce about 70% power.
10:58Investigators now know that the Boeing 737's engines weren't running at full power during takeoff.
11:05Why didn't the pilots notice?
11:08The efforts to recover Air Florida Flight 90 pay off.
11:17Investigators look to a key piece of wreckage for answers.
11:21They hope the engine pressure ratio gauge, or EPR, will help explain why the plane didn't lift off with full power.
11:29The EPR is connected to a sensor at the front of the engine.
11:32It calculates thrust by measuring the increasing air pressure passing through it.
11:38Your throttles?
11:39Okay.
11:41The gauge tells pilots when they have enough power to climb.
11:44If it was malfunctioning, it might have given the crew a faulty reading.
11:51The first officer had doubts about the EPR.
11:54God, look at that thing.
11:56That don't seem right.
11:57Does it?
11:58But the captain made the mistake of only focusing on the aircraft's speed.
12:03Yes, it is. There's 80.
12:05And ignoring the irregular reading on the EPR gauge.
12:08Huh? Maybe it is right.
12:12Close examination of the gauge reveals something strange.
12:18Can't be right.
12:20The needle is displaying an impossible reading.
12:22They indicated the engines were producing more power than the engines were capable of producing.
12:28That was a huge red flag.
12:31It seems likely that the gauge was giving a false reading throughout the short flight.
12:36Pilots were seeing more power than they were getting.
12:38So, what would have caused that?
12:40Did snow and the bitter cold affect the reading?
12:43They focus on the EPR's tiny sensor at the front of the engine.
12:50If it was coated with ice, it could have sent incorrect data to the cockpit.
12:55I got a hold of another 737 because I already suspected the engine pressure ratio gauges.
13:00To test his theory, McAdul uses tape to simulate ice covering the engine sensor.
13:08He then recreates the pilot's actions on the day of the flight.
13:12Okay, start her up.
13:14And records the sound of the engines.
13:21Keep throttling up.
13:23Until the engine gauges match the target set by Flight 90's crew.
13:30Got it.
13:33McAdul compares the sound of his test flight to engine noise captured during Flight 90's takeoff.
13:40That's a perfect match.
13:42I concluded that both engines were blocked with something, probably ice.
13:49Investigators realize the iced-over sensors caused pilots to believe they had enough power to climb.
13:54As the 737 speeds along the runway,
14:00Pettit begins pushing the thrust levers forward, aiming for the target of 2.04 EPR.
14:08Because the EPR sensors are blocked with ice, the gauge shoots up quickly and gives the crew a false reading.
14:13The Air Florida pilots attribute the unusual engine behavior to the bitterly cold weather.
14:26Seconds after liftoff, the stick shaker activates, warning the pilots that they are beginning to stall.
14:33Air speed.
14:38Forward, forward, forward.
14:40And with ice on the wings, it's impossible to recover.
14:51They did apply full power.
14:52But that was only about five seconds before impact. It was too late.
15:00But an important question lingers.
15:03Why didn't the plane's anti-icing system keep the sensors clear?
15:09The answer may be found when the team turns its attention to the pilot's pre-departure preparations.
15:14EPR all the way to 2.04. Set. Anti-ice. Off.
15:22Investigators are surprised.
15:24Ladies and gentlemen, we've just been cleared on the runway for takeoff.
15:26Unbelievable.
15:28One of the worst snowstorms and they have their anti-ice turned off.
15:32The Florida-based pilots seem to be following their usual warm weather routine.
15:37They weren't in the cold weather scenario mindset at that moment.
15:40Investigators wonder about the crew's cold weather experience.
15:45They study Captain Wheaton's records.
15:48Unsatisfactory adherence to regulations.
15:51Checklist usage, pre-flight, unsatisfactory. Flight procedures, unsatisfactory.
15:57And learn he has a history of errors, especially during takeoffs and landings.
16:04The captain's history of poor decision-making helps to explain his unconventional de-icing maneuver.
16:09Going to get your wing now.
16:11Using the exhaust of the plane in front.
16:14What they really did was get some warm air on a part of the leading edge of the wing,
16:21and any snow that was clinging to it ran back as water and refroze.
16:27Did they get you? Can you see your wing tip?
16:31I got a little bit on mine.
16:33Consequently, they did a lot more harm to their aircraft.
16:36Investigators believe the pilots underestimated the dangers they were facing.
16:43Neither pilot was really used to flying in snow or, you know, wintertime conditions.
16:48The captain had, I think it was eight takeoffs in that kind of weather.
16:53The first officer who was going to make the takeoff as a pilot flying had two experiences.
17:00They were literally unqualified.
17:02Investigators have now identified the factors that led to the tragic accident in the Potomac River.
17:07The captain's poor judgment, combined with both pilots' inexperience flying in winter weather, proved deadly.
17:15God, look at that thing. That don't seem right. Does it?
17:21The captain should probably have said,
17:23Hey, wait a minute, let's abort this takeoff and let's figure out what's wrong with these engines.
17:28We're going down, Larry. I know it!
17:30The accident occurred because of accumulation of numerous decisions that were made by this particular flight crew.
17:44The Air Florida disaster was a wake up call to the aviation industry.
17:48Northern airports now have plane de-icing facilities near the runway for use just prior to takeoff.
17:55Pilots and regulators now better understand the risks of flying in icy conditions.
18:01Even the most rule-abiding pilots are powerless to battle frozen wings if they've received misleading training.
18:18On a frosty winter afternoon, 26 passengers are taking Comair flight 3272 from Cincinnati, Ohio to Detroit, Michigan.
18:29It's a short one-hour trip on board an Embraer 120, a Brazilian-made turboprop.
18:36First officer Kenneth Rees and Captain Dan Carlson are on the third leg of the day.
18:42The first officer is at the controls.
18:44Out of Detroit, we're looking at 239 radio.
18:48Heading 030 to join the arrival. Comair 3272.
18:52For now, the crew has the plane on autopilot.
18:57As they descend from 19,000 feet towards their destination.
19:02Just some bumps.
19:04They hit some unexpected turbulence.
19:0615 minutes before their scheduled arrival.
19:11Let's run the descent check.
19:12Ice protection.
19:15Windshield, props.
19:17Standard 7.
19:18Pressurization.
19:24Comair 3272.
19:26Now turn left, heading 090.
19:29Heading 090, Comair 3272.
19:31The pilots make their final turn, and the plane banks left.
19:41Looks like your low speed indicator.
19:44Yeah, I see it.
19:45Power.
19:47Thanks.
19:49For some reason, the aircraft doesn't gain speed.
19:53The autopilot disconnects.
19:56Then the plane rolls steeply to the left.
19:59We're in the dives. We're in the dives.
20:00We're in the dives. We're in the dives.
20:01We're in the dives.
20:02We're in the dives.
20:03We're in the dives.
20:04We're in the dives.
20:05Oh, God.
20:07No.
20:08You never give up.
20:09You do what you gotta do to try to make it.
20:10Come on.
20:11Get out of me for God's sake.
20:12You never give up. You do what you got to do to try to make it.
20:23Come on! Get out of it, for God's sake!
20:42Come on!
20:54Comair Flight 3272 has crashed into a field 22 miles from the Detroit airport.
21:01All 26 passengers and three crew members are dead.
21:06By morning, a team from the NTSB begins recovering pieces of wreckage for analysis.
21:19What a mess!
21:21Richard Rodriguez leads the investigation.
21:26The team gets a lucky break when the flight recorders are recovered in good condition.
21:31Let's get those both packed up.
21:34They hope the devices will help them unravel the mystery of how a routine flight ended in disaster.
21:44Okay, we all ready?
21:47A first glance at the flight data is enough to give Rodriguez a solid lead.
21:514,000 feet, and it falls from the sky.
21:57The aircraft's sudden plunge could be the result of icing.
22:01This occurs when a buildup of ice on the plane's wings leads to an aerodynamic stall.
22:07Ice reshapes the wing surface, so these aerodynamic surfaces aren't doing what they're supposed to do.
22:14If frozen wings caused the plane to stall, the team wonders why no other aircraft was affected by the weather.
22:22None of the other airplanes that were on approach to Detroit experienced any problems,
22:27so we needed to look hard about what was unique about this airplane.
22:37Come on! Get out of here for God's sake!
22:41We're gonna dive! We're gonna dive!
22:43What was so different about flight 3272 that weather made it fall out of the sky?
22:59Investigators need to learn all they can about the weather conditions faced by the pilots of Comair flight 3272.
23:06Okay, let's pull up the weather data.
23:10The weather data began to paint a picture of an airplane that was on approach,
23:15flying in what were considered light icing conditions.
23:20According to Detroit air traffic controllers, other aircraft reported icing conditions.
23:26Strangely, the Comair pilots didn't.
23:30Comair 3272, just a little turbulence, but that's all.
23:35It definitely flew through icing conditions.
23:39The Embraer 120 has both anti-icing and de-icing systems for winter weather flying.
23:45Let's play it.
23:47Something doesn't add up.
23:51Let's run the descent check.
23:52They turned to the cockpit voice recorder for answers.
23:54Ice protection.
23:55The pilots are required to go through an approach checklist.
24:00One of the items is the various anti-icing facilities that they have on the aircraft.
24:07The anti-icing protection uses electricity to heat the windshield and propellers.
24:13But the wings have a different system.
24:16They rely on mechanical devices called de-icing boots.
24:19Made of rubber, the boots are part of the leading edge of the wings.
24:24When activated, they inflate, expand and crack off accumulated ice.
24:29The ice is just hard enough that it cracks and the air stream blows it away.
24:34Pressurization.
24:35It's reset for our landing in Detroit.
24:39Rodriguez listens, waiting for the pilots to activate the de-icing boots.
24:44Landing lights. Landing lights off.
24:47Crossfeed. Crossfeed's off.
24:51That completes that.
24:53He makes a stunning discovery.
24:55There was no discussion to indicate that they were concerned about icing on the aircraft.
25:01Investigators check dispatch records to determine if the crew was briefed on the weather conditions.
25:07The flight had received their papers for dispatch, which included warnings about icing in the Detroit area.
25:14Could be some ice in our path.
25:17They knew they were going to hit ice, but then never popped the boots.
25:22NTSB investigators wonder why pilots with plenty of winter flying experience never activated the de-icing boots.
25:32The captain was known as a by-the-book type of pilot.
25:37They contact other Comair pilots for information.
25:40So if ice is just beginning to form on your wing, what would you do?
25:44You'd wait? You'd wait?
25:46Okay.
25:47We were getting feedback that they'd wait until one quarter to one half inch of ice had accumulated before they activate the de-ice boots.
25:55Why would you wait? Bridging.
25:58When de-ice boots were first invented, they inflated at a very slow pressure and stayed inflated for a while.
26:04And pilots became concerned that ice might form over the inflated shape of the boot, a phenomenon known as bridging.
26:12But bridging on de-icing boots hasn't posed a risk to modern airlines for many years.
26:18The de-ice boots on this airplane inflate rapidly.
26:21In less than a second would break off any amount of ice that was accumulated and deflate again right away with vacuum suction.
26:29So de-ice boot bridging was not going to happen on this airplane.
26:32Alright, let's take a look at the manuals these guys are following.
26:36Investigators need to find out what guidance the crew received to deal with icing.
26:42They compare Comair's manual to that of the manufacturer, Embraer.
26:47That leads to a surprising discovery.
26:50Comair manual tells them to wait.
26:52The Comair manual advises pilots to wait until half an inch of ice forms before de-icing, while the Embraer manual says something different.
27:00Activate boots at the first sign of icing.
27:04The team must find out why the pilots were given conflicting instructions.
27:09They soon uncover a revision to the Embraer flight manual.
27:13It clearly explained the need to de-ice quickly.
27:17So why didn't the Comair pilots follow that procedure?
27:20Could be some ice in our path.
27:22What a shock. Ice in January.
27:27Investigators learned that the FAA approved the Embraer revision.
27:32But it overlooked the critical next step, instructing airlines to adopt the change.
27:37Why not make it mandatory? It's a no-brainer.
27:41While the FAA had a great deal of information, they never did officially sanction a standard that should be adhered to.
27:49Investigators now know what led to Comair flight 3272's fatal crash.
27:55Just before landing, the pilots entered icing conditions.
28:01Ice protection.
28:02But the captain waited to activate the de-icing boots.
28:05Props. Standard 7.
28:08Per the instructions in the flight manual, they were waiting until a significant amount of ice had accumulated.
28:14Comair 3272. Reduce speed 150.
28:17The controller then instructed them to reduce speed as they approached the airport.
28:23Speed 150, Comair 3272.
28:26As the plane slowed, the drag from the ice on the wings increased.
28:31To make matters worse, the plane was on autopilot.
28:35When the autopilot is on, the pilot can't feel what's happening until he starts to see something on the instrument gauges it.
28:47Looks like your low speed indicator.
28:49Yeah, I see it. Power.
28:50Thanks.
28:52But that action comes too late. The left wing had already lost lift.
28:58The aircraft rolled rapidly to the left. They went from about 45 degrees angle of banks to the left to 140 degrees.
29:09Which is basically inverted.
29:11When that nose pitched straight into the ground, their fate was sealed.
29:18The NTSB faults the Federal Aviation Administration for failing to establish adequate standards for flights in icing conditions.
29:37Ultimately, we didn't believe that the FAA put forth the right leadership to help dispel the myth of de-ice boot bridging.
29:48They recommend that all pilots be instructed to activate the boots the moment they encounter icing conditions.
29:54Our mission is to find the cause of an accident, make recommendations that will prevent it from ever happening again.
30:00And when several mistakes in the cockpit add up to frozen wings, a flight spirals out of control above the remote steps of Patagonia.
30:12On a cold night in Argentina,
30:14Positive rate.
30:16Sol flight 5428 is headed from Neuken to the port city of Commodoro Rivadavia on the coast.
30:26Tonight, Captain Juan Raffo is piloting a Swedish-made Saab 340 turboprop.
30:34Adriano Bolati is his first officer.
30:37Gauge autopilot.
30:38The aircraft begins to climb to a cruising altitude of 19,000 feet.
30:47Buenos Aires, Sol flight 5428, reporting waypoint Ecopa.
30:50We are climbing through flight level 50 for 190.
30:54ATC Buenos Aires, received.
30:56Looks like we're picking up some ice.
31:12Nothing to worry about, we're expecting some light icing.
31:17Should be better when we get to 19,000.
31:19At that higher altitude, water droplets freeze solid before they can cling to the aircraft.
31:27But as they climb, the icing conditions worsen.
31:38Captain Raffo decides to change the plan.
31:43Okay, let's get it down to where it's warmer to melt it off.
31:46Roger.
31:48Sol flight 5428, requesting descent to flight level 140.
31:51Sol 5428, you are cleared to 140.
31:56As Sol 5428 descends to a lower altitude.
32:01All finished?
32:03The flight continues without incident.
32:06Feel that?
32:10The propeller is vibrating.
32:12But then, everything changes.
32:14Put them on max.
32:15Roger.
32:16Roger.
32:17Oh, hell.
32:19What's wrong?
32:20I don't know.
32:21What's wrong?
32:22I don't know.
32:23Pull back!
32:24Pull back!
32:25Pull back!
32:26Harder!
32:27I'm trying!
32:28I'm trying!
32:29Thank you!
32:30Come on!
32:31Come on!
32:32Come on!
32:33Come on!
32:34Come on!
32:35What's wrong? I don't know!
32:47Pull back! Pull back! Pull back! I'm trying!
32:55Come on!
33:01Mayday! Mayday! Slow flight!
33:03Mayday! Mayday! Mayday!
33:13The turboprop crashes in a remote region of Patagonia.
33:21There are no survivors.
33:2422 fatalities.
33:27My God.
33:28Augusto DeSantis is coordinating the various teams from Argentina's Civil Aviation Accident Investigation Board.
33:36Catalog every piece, no matter how small.
33:44While some members of the team remain on the site, DeSantis studies the weather conditions on the night of the crash.
33:51This is the flight path from Neuquen to Commodoro. Look what's waiting for them here.
33:59They flew right into this cold front.
34:02The information showed that there was severe icing.
34:08Was ice a factor in the accident?
34:11Investigators focus on the plane's de-icing systems.
34:15All that survived are the valves.
34:17The valves.
34:18The valves are a key component of the de-icing boots.
34:23Their main function is to control the flow of pressurized air that inflates the boots on the plane's wings.
34:29We isolated the anti-ice valve and we analyzed what was left of it.
34:37The tests revealed that pressurized air was passing through the valves.
34:42Take a look. No failures.
34:44The team must look elsewhere for new leads.
34:47So there was no doubt that the systems were being operated and that they were working.
34:53They turned to the flight data recording.
34:58Okay, look here.
35:00Their airspeed dropped to 129 knots, then 126 knots.
35:05They're in ice.
35:07They should be speeding up, not slowing down.
35:10When climbing in icing conditions, the minimum speed is 160 knots.
35:16They're 30 knots below that.
35:17They lost so much speed, they stalled.
35:25The speed was progressively decreasing, which harmed the aircraft aerodynamically.
35:36Oh hell!
35:38And took it to a final stall and loss of control.
35:40I don't know if you know.
35:43You pick up ice, you should increase your speed.
35:46Pretty basic.
35:48Why didn't these guys do that?
35:50The team wonders why pilots would make such a fundamental error.
35:54They hope the flight data will provide more clues.
35:57Let's check their autopilot settings.
36:00Did the pilots use the correct setting for the weather conditions they faced?
36:04It was set to vertical speed after they leveled off.
36:06Vertical speed is an autopilot setting that controls the rate of climb.
36:13But to get through ice faster, the pilots should have selected the setting that maintains speed.
36:20That's their mistake.
36:22Vertical climb not only slows the plane, it also pitches the nose upwards.
36:27It's going to expose the whole underside of the wing and you're just going to pack on ice even faster.
36:31What's worse, the Saab turboprop isn't equipped with anti-ice protection on its underside.
36:38This ice buildup adds weight on different parts of the aircraft, which makes it less controllable.
36:45It becomes a major effort for the crew or the autopilot to control the aircraft.
36:50The question is, why did the pilots let this happen?
36:59Airspeed 140 knots. Check.
37:02Investigators hope the cockpit voice recorder of Sol Flight 5428 will help explain how the pilots responded to the buildup of ice.
37:12It's like we're picking up some ice.
37:23There it is.
37:25I don't have to worry about it.
37:28We were expecting some light ice.
37:30I don't know if one might be more than we thought.
37:32They were aware that there was ice buildup, and that it was progressing.
37:43They're just focused on getting above the bad weather.
37:48The pilots' strategy was to climb above icing conditions.
37:51They can't. They're carrying too much ice to climb any higher.
37:56Once it became apparent that they were picking up ice quickly and they were unable to climb,
38:01they make a decision to descend and find an altitude where the temperature is such that that ice would melt.
38:06I don't think that helped very much. Ice is hitting everywhere.
38:11It's okay. We're going to stay at this altitude for now. We'll keep de-icing until we get there.
38:15The pilots can't rely entirely on de-icing. They also need to push the throttles forward to increase power.
38:23While they were aware of the ice buildup and how things were progressing,
38:28they were not taking strong measures to change the situation.
38:36Feel that?
38:38The power is vibrating.
38:40First sign of stalling.
38:42It's because there's too much ice on the propellers.
38:52What about Max? Roger.
38:54Propellers? They're misreading the signals from the plane.
39:00What was actually happening was a structural vibration of the entire aircraft.
39:05The aircraft was virtually dying.
39:09It was at a speed threshold where the next thing was the loss of control due to the loss of lift.
39:17As the plane begins to stall, Captain Raffo makes a dangerous call.
39:25Go back! Go back!
39:26You're trying to level the key.
39:27Unbelievable. They're making the stall even worse.
39:29It's a shocking revelation. The pilots are doing the opposite of what needs to be done to prevent a catastrophe.
39:39Mayday! Mayday! Mayday! Mayday!
39:42Go flight 5428! Mayday! Mayday! Mayday!
39:50Investigators now know why Sol 5428 crashed.
39:53A wrong autopilot setting here.
39:57A misread of the plane's vibrations here.
40:00And when they finally stall, try to pull the nose up to level off instead of trying to gain speed.
40:06What kind of training did these guys get?
40:09When investigators examine the pilots' training records, they make a surprising discovery.
40:15No training is done on what to do once the ice buildup has advanced and how to get out of that situation by increasing speed.
40:26It's the last piece of the puzzle explaining the fatal crash.
40:30It should be better when we get to 19,000.
40:33Investigators conclude that the airline's lack of proper training resulted in the pilots not only selecting the wrong autopilot settings.
40:40I can put it on vertical.
40:42Okay. The sooner the better.
40:44Roger.
40:46But also failing to increase speed in icing conditions.
40:58Oh hell! What's wrong? I don't know!
41:00What began as ice on the wings resulted in a mismanaged...
41:04Pull back! Pull back!
41:06...and ultimately unrecoverable stall.
41:08The problem was that the actions they took were not effective enough in order to mitigate the situation.
41:14To be able to mitigate that situation.
41:19Pull back! Pull back!
41:21Pull back!
41:25You're dead!
41:27What are you doing now?
41:28Pull back!
41:37In their final report, investigators recommend sweeping changes to commercial pilot training for icy conditions.
41:44Icing has been with us since Lindbergh, who iced up as he went across the Atlantic. And it will continue to be with us in the future.
41:56Three different cases of frozen wings, all leading to tragic outcomes.
42:02But the insight gained from these accidents led to improved flight safety in winter conditions across the globe.
42:10Cross the globe!
42:11So, let's look at this!
42:12...and bring the
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