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00:01While a passenger livestreams an approach into Pokhara Airport in Nepal...
00:06The plan is to go paragliding with my buddies!
00:13Add power!
00:16Yeti Flight 691 falls from the sky.
00:22What's happening?
00:2872 people are killed.
00:31This was the deadliest crash involving Nepali Airlines ever.
00:40Eyewitness video gives investigators their first lead.
00:44That's at least an 80-degree left bank.
00:50When they analyze the flight data...
00:53Wow.
00:54They're shocked to discover the engines weren't generating power.
00:59No power, torque indication zero!
01:01There should have been warning lights.
01:03Why didn't they figure it out?
01:05You start to question, what was going on in the cockpit?
01:09Me, me, me, me!
01:13Oh, fuck!
01:16No power!
01:18No power!
01:19No power!
01:21No power!
01:24No power!
01:24No power!
01:25No power!
01:29No power!
01:33Yeti Airlines Flight 691 flies south of the Himalayan mountains in Nepal.
01:43There are 68 passengers on board, including Sonu Jaiswal, a tourist from India, heading to Pokhara to paraglide with friends.
01:57Pokhara Tower, Yeti 691, descending through 12,500 feet.
02:03Captain Kamal Casey is the senior officer and the pilot monitoring instruments on today's flight.
02:10Roger, Yeti 691, 12,500 feet.
02:15He's also a veteran of more than 21,000 flying hours.
02:22We had absolutely the utmost respect for Captain Kamal Casey as he was a veteran in the Nepalese skies.
02:31And he was quite a humble and knowledgeable guy as well.
02:36It's very clear.
02:38We'll be good for visual landing.
02:41Flying the plane from the left-hand seat is Captain Anju Katawada.
02:45She's flown more than 6,000 hours.
02:50Captain Katawada has a very special history.
02:53Her husband, he was a pilot with the same company.
02:57He was the first officer on the twin order and it crashed and he died some years earlier.
03:03Katawada decided to take up flying to honor his spirit.
03:08So she become a pilot.
03:118,500 feet.
03:12While Captain Katawada is an experienced commercial pilot, she has only 186 hours on the ATR-72.
03:30The ATR-72 is a turboprop twin-engine aircraft.
03:35It's a high-wing aircraft.
03:38It's a very stable, predictable and logical aircraft.
03:42And it's very good to fly here in the mountains and hilly regions of Nepal.
03:51Today's flight is a short 25-minute hop from Kathmandu to the tourist city of Pokhara.
04:02Yeti 691, expect to land on 1-2.
04:06Broadway 1-2, Yeti 691.
04:1015 miles from the airport, Yeti flight 691 is cleared for the approach.
04:17Hey everyone, exciting times as we're headed to Pokhara's new airport.
04:21Sonu Jaiswal is live streaming from the cabin.
04:24The plan is to go paragliding in the Himalayan foothills with my buddies!
04:333-1-0.
04:35Captain Katawada programs a heading for the approach to runway 1-2.
04:44You are in between the runway and the mountains.
04:48So you need to be very, very precise with your handling skills of the aircraft.
04:56Okay, visual, visual.
04:58Okay, visual.
05:01The pilots monitor their position carefully, keeping the plane clear of the mountains.
05:09Yeti Airlines 691 in sight, report final, runway 1-2.
05:14Call you on final for runway 1-2.
05:16Yeti Airlines 691.
05:21Gear down.
05:25Less than two minutes from the airport, the pilots configure the plane for landing.
05:31Okay, from here you can go manual.
05:33Okay, stand by.
05:37Disconnect.
05:39Captain Katawada disconnects the autopilot, then begins the first of two crucial turns to line up with the runway.
05:55Okay, flaps 30?
05:59Flaps 30.
06:01Continue descent.
06:03Okay.
06:07One minute from touchdown, the pilots run through the pre-landing checklist.
06:13Okay, landing gear.
06:14Down three green.
06:16Flaps?
06:1630.
06:21In the cabin, Sonu Jaeswal continues live streaming.
06:26We're getting pretty close now.
06:30As the flight gets closer to the ground, the landing seems trouble-free.
06:41But seconds from the runway, Captain KC realizes there's a critical problem with the engines.
06:47There's no power.
06:49There's no power.
06:53There's no power.
06:54When there's no power, that means they have very limited time at that altitude.
06:59They need to react quickly.
07:02Add power.
07:04Captain Katawada tries to power up, but the engines aren't producing any thrust.
07:11400 feet above the ground, the pilots face a critical situation.
07:20In the tower, the controller doesn't know that flight 691 is in any trouble.
07:25Yeti 691, runway 12.
07:28Clear to land.
07:30There's no power.
07:32No power.
07:33Add power.
07:37Captain Katawada pushes the throttles to the limit.
07:44There's no torque.
07:45Okay, give it to me.
07:48The more senior captain takes control.
07:588691.
08:01200.
08:04Flight 691.
08:04Flight 691 is stalling.
08:13While Sonu Jaeswal live streams the unfolding disaster.
08:22What's happening?
08:57Yeti Flight 691 has crashed in one of the worst possible places.
09:03The Seti River runs near to the airport through a huge gauze.
09:08That's where the plane crashed.
09:13The plane was completely destroyed in the impact.
09:18There was a huge flame burning.
09:23There was no possibility to find any survivor.
09:30The bodies of 71 of the 72 passengers and crew are eventually found and identified, including both pilots.
09:41This was the deadliest crash involving Nepali airlines ever.
09:49What could have caused a commercial airliner to drop out of the sky just seconds before landing?
10:03When investigators arrive at the crash site of Yeti Flight 691, they face a devastating scene.
10:13The wreckage was scattered all over the place.
10:18The first impact was before the river, where the parts of the left wing was detached.
10:24Some parts were located on the bottom of the river guards.
10:26The rest of the pathway at the side of the river.
10:36Under the supervision of Nepali investigators, the wreckage, along with the black boxes and central processing card from the plane's
10:44computer,
10:45are sent for analysis to labs in France and Singapore.
10:50It's really not uncommon in an accident investigation to have to send something out for closer investigation.
11:05Nepali investigators wonder about Flight 691's orientation when it hit the ground.
11:11Looks like this is from the first point of impact.
11:16That's a flap from the left wing and an aileron tip.
11:22So the left wing must have hit the ground first.
11:29The plane crashes wing down.
11:31What that suggests to investigators is that the plane crashed out of control.
11:36You would never intend to have it be that way.
11:38You'd always try and level it out and crash as close to a regular attitude as you can.
11:44Maybe the plane's stalled.
11:46Maybe the plane's stalled.
11:48You may be right.
11:50Check this out.
11:58It's gone viral.
12:05A witness had filmed the plane during the final moment of the flight.
12:11It appears that the left wing lost lift and dipped severely.
12:17That's at least an 80 degree left bank.
12:25It sure looks like a stall to me.
12:32When you see evidence that looks like a stall, you immediately start questioning what could have led to that and
12:38you go back to what's going on during that approach.
12:48This is not an easy approach.
12:50This is not an easy approach.
12:51They'd have to fly between the runway and the mountain and make two left turns before lining up with runway
12:5812.
12:59And this is where the plane crashed.
13:02And just before the crash, they were beginning their final left turn.
13:08Did the pilots bank too far during one of the turns and stall?
13:15They would have had to go from zero to an 80 degree bank in a few seconds.
13:20Yeah.
13:23It suggests there was a problem with the plane.
13:26Yeah.
13:29You might want to focus and see if there's any smoking guns in the maintenance records.
13:33If there was anything wrong that somebody knew about, maybe they tried to fix it and it didn't get fixed.
13:40I've got maintenance records.
13:47Investigators go through the plane's records in search of any gaps in maintenance or inspections.
13:56I'm not seeing anything.
13:59Everything checks out.
14:02Maybe the controller knows something.
14:06Yeah.
14:08The air traffic controller may have heard something in their conversation with the pilots.
14:13Picked up something that isn't really evident from the tape.
14:19Did you have visual contact with the aircraft?
14:27Did you see or hear anything suggesting a problem with the plane?
14:31No.
14:32I was flying normally when I had visuals with it.
14:34It was just out of sight right before the crash.
14:39Then I heard it.
14:43Explosion.
14:48Explosion.
15:01Did the pilots say anything suggesting a problem with the plane?
15:05Nope.
15:06Not much.
15:09Okay.
15:12So...
15:13Do you know what happened?
15:20Not yet.
15:27In the early stages, you'd want to look at anything witnesses might have to say, anybody who might have seen,
15:33heard, or otherwise noticed the crash.
15:37The controller offers little insight into why the plane stole.
15:41Then a witness to the accident comes forward.
15:44There?
15:45That's where you saw the plane?
15:49He had the credibility because he was an engineer.
15:53And you said that you saw the propeller spinning just before the crash?
16:01When you see a propeller rotating, it means it moves very slow, otherwise you cannot see it moving.
16:07Okay. Thank you.
16:10The slow rotation of the propellers could indicate there was a problem with the engines that drive them.
16:19Quick update. Sounds like engine failure.
16:23Yep.
16:24We need to talk to the French about their engine analysis.
16:31Hello.
16:35Nepali investigators now joined the team from France to examine the wreckage of Yeti Flight 691.
16:43Engines are badly damaged.
16:45Can't tell if they failed in flight.
16:51Most of the engines were consumed by fire, so they couldn't learn definitively whether they were producing power.
17:01Look at that prop.
17:06Investigators notice something telling on a propeller hub.
17:13Looks feathered.
17:22When propellers are feathered, their edges face forward and cannot produce thrust.
17:29It's like putting your car in neutral position.
17:32You can push on the gas as much as you want, but nothing is going to happen.
17:41It's actually stuck in a feathered position.
17:45Okay.
17:52This one moves freely, but it could have moved on impact.
18:01This one is stuck too.
18:05So, two of them were in the feathered position when they hit the ground.
18:13Normally, propellers are feathered on the ground after shutdown.
18:16That prevents them from spinning in the wind and damaging the engine.
18:21There is, however, one exception.
18:24An automatic feathering unit will feather that propeller immediately as soon as an engine failure is detected.
18:30Perhaps faster than the pilot can do it.
18:35Were the props feathered automatically in flight due to engine failure?
18:40Investigators download the data from Flight 691's multifunction computer to find out.
18:46The multi-function computer stores information about the automatic feathering unit in its memory.
18:53They're going to be able to learn whether the auto feather unit feathered one engine or both engines.
19:09It never activated.
19:12If you learn that the auto feather system didn't feather the propellers, that immediately raises the question, who or what
19:20did?
19:23Were the propellers feathered manually?
19:26Investigators consider a crucial piece of wreckage recovered from the scene, the central control pedestal.
19:33The central pedestal is located between the pilots.
19:37And here you have the power levers, you have the flaps lever, and you have the condition levers, which controls
19:43the propellers.
19:46The flaps are stuck at 30.
19:48That's where they should be for landing.
19:54Condition levers are moving freely.
19:57It doesn't tell us much.
20:01Hm. Look at this.
20:10Witness mark.
20:13You're looking for witness marks, the marks that one aircraft component makes against another at the time of impact.
20:20And those marks will suggest, in the case of the central control pedestal, where the controls were positioned at impact.
20:30The witness mark suggests that the pilots could have put the left lever in the feathered position.
20:37Maybe some other debris caused the witness mark.
20:40There's no witness mark for the right condition lever.
20:47Were the propellers feathered by the pilots?
20:50Or did the witness marks occur on impact?
20:53We're gonna need the flight data recorder download to settle this.
21:01The flight data recorder doesn't record the propeller blade angle.
21:05But it does record certain parameters that let investigators infer whether the propellers were feathered, and if so, when.
21:24The torque and propeller speed drop at the same moment, when the engine's at idle.
21:31They find evidence that the pilots feathered the props one minute before the crash.
21:38When the propellers are feathered, the torque drops and the propeller's RPM speed drops.
21:45That's what the witness was able to see when he reported spotting the individual propeller blades.
21:52How did they make that mistake?
21:59What was going on in the pilot's mind?
22:03What was going on in the cockpit?
22:05What's happening?
22:16What was happening?
22:18Pick it up 24 minutes into the flight.
22:21Right before the propellers were feathered.
22:25Investigators listened to the cockpit voice recording from Yeti Airlines Flight 691
22:30to understand why the pilots feathered their propellers when they did.
22:34Okay, from here you can go manual.
22:37Okay, stand by.
22:42Disconnect.
22:44Okay, flaps 30.
22:47Flaps 30.
22:49Continue descent.
22:51Okay.
22:53Stop, Thompson.
22:55Where are we at here?
22:57Time is 10 56 35.
23:04According to the FDR, the flaps did not move to 30 at this point.
23:10But this is when the props were feathered.
23:16The FDR shows that when the pilot flying commanded flaps 30, the flaps didn't move.
23:23But at the same moment, the prop RPM decreased and torque went to zero.
23:29The pilot has pretty obviously feathered the engines instead of moving the flaps.
23:42They must have mixed up the flap levers with the condition levers.
23:47And Captain Casey was the pilot monitoring.
23:52How could a captain make that mistake?
23:59In most airline accidents, pilot error is a factor.
24:05That can be because of inadequate training, experience.
24:09It can be because of, uh, too little rest.
24:14But there can also be other factors impairing their decisions.
24:18Here you go.
24:24The team reviews results from the pilot's toxicology tests.
24:31Nothing on Captain Katiwata.
24:38Same with Captain Casey.
24:43Maybe they weren't adequately rested.
24:48According to the airline's records, both pilot schedules were within guidelines.
24:52Suggesting adequate rest.
24:55And their medical certificates are current.
24:58They conclude that something other than impaired judgment caused the pilots to feather the props by mistake.
25:05At this point, you'd have to wonder what might have been going on in the cockpit
25:09that would lead him to be distracted into setting the propellers to feather instead of setting the flaps for landing.
25:18Did the location of the condition levers on the pedestal play a part in the captain's error?
25:24They examine an ATR-72 pedestal.
25:29So, I reach over for the flaps, but I put my hand on the condition lever instead.
25:40The flap lever and the condition lever are very close together on the pedestal.
25:46I want to move the flaps to the 30-degree position.
25:51But instead, I move the condition lever to feathered.
26:00The flap and condition levers have the same range of motion and stop in similar positions.
26:09It's not a stress that they could have mixed up the levers.
26:12And, don't forget, Captain Casey was where I'm sitting.
26:18Right.
26:23Mercer memory is very important for a pilot because you can do sequences without being conscious about it.
26:30But when you move to another seat on the other side, suddenly that flow is disturbed
26:36because now you have to use the opposite hand.
26:40Oh, that feels a lot less natural.
26:46And much easier to mix up.
26:51Okay. Flaps 30?
26:54Flaps 30.
26:57Continue to sense.
27:01The pilot monitoring move the condition levers instead of the flap lever.
27:06That should be impossible, but it has happened before.
27:11I once asked for flaps and the pilot monitoring selected the gear down.
27:16And those levers are far apart.
27:21Still, it's hard to imagine looking at these levers that you'd get them confused.
27:27True.
27:35Maybe he wasn't looking at them.
27:40Why would an experienced captain not check which levers he was moving?
27:50Okay, visual, visual.
27:52Okay, visual.
27:54Investigators returned to the voice recording of Yeti Airlines Flight 691
27:59to determine if the captain's attention was elsewhere when he selected the wrong levers.
28:04Okay, make sure you stay between the mountains and the runway.
28:07They revisit the moment just before the propellers were feathered.
28:12Keep your power nose up.
28:14Keep visual with the tower.
28:16Don't go too far.
28:17Okay, copy that.
28:21Okay, stop for a second.
28:25He's giving her a lot of instructions.
28:29Maybe that's the distraction.
28:32But she's a very experienced pilot, so why is he doing that?
28:38When you're giving instruction, that's an added mental stress.
28:41It's an added cognitive load.
28:44It's very distracting.
28:46Let's start from the top.
28:49Poker Tower, Yeti Airlines 691.
28:53Yeti Airlines 691.
28:56Tower, Yeti 691.
28:59Descending through 12,500 feet.
29:03Roger, Yeti 691.
29:0512,500 feet.
29:07Expect to land on runway 30.
29:10Runway 30.
29:12Yeti 691.
29:15They discover that flight 691 was initially cleared to land on a different runway, runway 30.
29:23But eight minutes later, there's a change of plan.
29:26If traffic permits, let's land on runway 12.
29:30Then you'll be approved for runway 12 without any instructor-pilot supervision.
29:34Okay, runway 12.
29:38Not only is he monitoring the flight, he's approving her to land at Pokhra's new airport.
29:46Investigators discover Captain Casey was instructing pilots on how to land on both runways at the new airport.
29:54I flew with Captain Kamal Casey just two days before for my route qualification into Pokhra International Airport.
30:03But why runway 12?
30:08You'll be approved to land in both directions.
30:10Copy that.
30:17Okay, stop it.
30:19So Captain Khatawada is cleared for runway 30.
30:24And Captain KC decides much later in the game, he's approving her for runway 12.
30:31Captain Khatawada had landed on runway 30, but never 12.
30:37Runway 30 is a straight-in approach.
30:44In runway 12, you follow a narrow track next to the mountains, and you turn left twice to line up
30:50with runway.
30:52So Captain Casey put Captain Khatawada on a more difficult landing.
31:02Runway 12 was a challenging approach for a pilot with just 185 hours on the air.
31:09Did Captain Casey properly prepare Captain Khatawada for the difficult approach to runway 12?
31:18The best way to prepare a pilot for such an approach would be to do a proper briefing.
31:24Maybe they have photos, videos, simulator training if available.
31:32Investigators examine Captain Khatawada's training records.
31:37She spent no time in the simulator training on runway 12.
31:41What about a formal briefing?
31:44There's no documentation related to training on 12.
31:48I've got Captain Casey's flight history.
31:52Was Captain Casey even qualified to train others for landing on runway 12?
31:58Turns out he had only landed on 12 twice.
32:03A bit of experience, but not enough.
32:09Because of his low experience and also Khatawada's low experience on the aircraft.
32:14I find that a bit strange.
32:18I wonder if it's even possible to do a stabilized visual landing using that approach.
32:32A stabilized visual approach is one that's conducted with the runway in sight at a normal rate of descent with
32:40landing flaps and landing gear down at the proper airspeed and with all checklists completed by a certain point.
32:50There's just over one mile between the completion of the last turn and the runway.
32:57That's going to give you just over 30 seconds from lining up to landing. It's very tight.
33:08A visual landing can increase the workload because they have to make tiny adjustments all the way through the pattern.
33:16Let's see how they handle the workload.
33:20Okay, make sure you stay between the mountains and the runway.
33:23To understand how the pilots dealt with the final approach to runway 12, investigators returned to the CVR.
33:31Keep your power nose up.
33:34Keep visual with the tower.
33:36Don't go too far.
33:38Okay, copy that.
33:40Remember, you need to make an early turn here.
33:44Okay, a beam tower.
33:47Gear down.
33:48Gear down.
33:54Can I fly it manually?
33:56Wait.
33:57Wait, not yet. Keep going straight.
34:00After flaps 30, then you're good to go manual.
34:04Hold on.
34:05Captain Casey is so focused on pointing out landmarks outside the cockpit, he's not paying attention to what's happening inside
34:12the cockpit.
34:16It's normal to let the less experienced pilot fly the aircraft and the most experienced pilot do the analysis.
34:24Okay, flaps 30?
34:27Flaps 30.
34:32Continue descent.
34:33Okay.
34:39He probably didn't even look down to see what lever he was by.
34:43But there is still an opportunity to catch the mistake when they do the landing checklist.
34:52The before landing checklist was an opportunity for him to look down at that control pedestal and see that he
34:59had moved the condition levers into feather.
35:02I'm almost certain they could have recovered right up until the last few seconds.
35:08Did the pilots' failure to follow their checklist ultimately determine their fate?
35:19Nepali investigators continue listening to the CVR of Flight 691 to learn whether the pilots followed the proper procedures before
35:27landing.
35:28Before landing checklist.
35:34Okay.
35:35Landing gear.
35:37Down three green.
35:38Flaps?
35:3930.
35:40Wait.
35:42Captain Kariwata said the flaps are at 30, but according to the FDR, they're still set at 15.
35:49Neither pilot checked the flap settings.
35:54If Captain Casey saw that the flaps were not at 30, he may have realized he had moved the wrong
36:00lever.
36:01Power management?
36:02Takeoff.
36:03TLU?
36:05Low speed.
36:06Icing, AOA?
36:08Check.
36:09External lights on?
36:10On.
36:11Complete.
36:13They rushed it.
36:17The before landing checklist was done very fast, like bam, bam, bam, bam, bam.
36:22And I doubt any of them looked at the flap setting.
36:25They just answered by memory.
36:28And with the props feathered, there should have been warning lights.
36:33Why didn't they figure it out?
36:45When the propellers are feathered, they're no longer providing power to the generators.
36:51An oral and visual ELEC warning alerts the pilots that they're losing electrical power.
36:57What is this?
36:58Huh?
37:00ELEC is on CAP.
37:04The ELEC light comes on to warn the pilots, hey, you've got a big electrical problem.
37:10Checked.
37:10Check.
37:12Someone clicked off the warning.
37:13They clicked off the warning without figuring out why it even came on.
37:20It's hard to tell why Captain Kamal KC responded checked to the electrical light.
37:26Checked.
37:28Would you pull out a quick reference handbook and start working a long electrical failure procedure?
37:33Or would you recognize, hey, I'm landing in less than 60 seconds.
37:37Let's just bring the plane in and deal with the problem on the ground.
37:41We just continue, right?
37:43Yes. Continue turn.
37:49What's that click about?
37:56FDR data shows this is where the flaps goes to 30.
37:59So he notices the flap is not set at 30 and corrects it.
38:10And with so much workload, all he sees is the flap lever and doesn't notice that the propellers are feathered.
38:17When your workload increases, you get tunnel vision and you see less.
38:23That makes it very difficult because now you only focus on one thing.
38:29Okay, but why doesn't he figure it out when the engines have dropped to idle?
38:39Seconds from the runway, Captain KC realizes there's an issue with the engines.
38:44There's no power.
38:45There's no power.
38:48Add power.
38:51Even though the pilots see the engines are at idle, they are still unaware that the propellers are feathered.
38:58There's no power. No power.
38:59Add power.
39:03There's no torque.
39:04Okay, give it to me.
39:07In desperation, Captain KC takes control of the plane.
39:11You're landing, sir.
39:13No power.
39:14Torque indication zero.
39:16Two hundred.
39:1986-9-1.
39:21What's happening?
39:35He decided to fly the plane rather than try to diagnose the problem.
39:49One single glance around the cockpit could have told him that he had feathered the propellers.
40:01The final report of the Nepali Accident Investigation Commission concludes that the most probable cause of the accident was the
40:09inadvertent movement of both condition levers to the feathered position in flight.
40:17What strikes me about this is that it was a very normal situation. The only thing that went between success
40:25and failure was the slip of a hand.
40:30The proximity to terrain and sharp turn required to land on runway 12.
40:37Before landing checklist.
40:38Combined with a high workload and a lack of appropriate training all contributed to the crash.
40:47After the accident, Yeti Airlines tests the approach in the simulator with their pilots.
40:54Most of our pilots were not able to land on runway 12.
40:58Either they were high on approach or they were fast on speed.
41:05Yeti Airlines stops flying into runway 12 until they are able to establish a safe visual procedure and retrain their
41:14pilots.
41:16The commission recommends that the Civil Aviation Authority of Nepal ensures that a stabilized flight path is approved before allowing
41:24commercial operations at a new airport.
41:30After the accident, the victims of Yeti Air Flight 691 are mourned by a nation and fellow pilots remember their
41:39colleagues.
41:41For Captain Kamal Casey, I just want to remember him when he was alive and he was there with us.
41:53Captain Khatiboda, I respected her a lot.
41:58She will be remembered as an elder sister.
42:02And there is going to be always a void in the airlines that she is not there anymore.
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