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00:00While a passenger live streams an approach into Pokhara Airport in Nepal.
00:07The plan is to go paragliding with my buddies!
00:15Add power!
00:17Yeti Flight 691 falls from the sky.
00:24What's happening?
00:2672 people are killed.
00:33This was the deadliest crash involving Nepali Airlines ever.
00:42Eyewitness video gives investigators their first lead.
00:46That's at least an 80 degree left bank.
00:49When they analyze the flight data...
00:56Wow!
00:57...they're shocked to discover the engines weren't generating power.
01:01No power, torque indication zero!
01:04There should have been warning lights.
01:06Why didn't they figure it out?
01:09You start to question, what was going on in the cockpit?
01:12D-D-D-D-D
01:18Yeti Airlines flight 691 flies south of the Himalayan mountains in Nepal.
01:48There are 68 passengers on board, including Sonu Jaiswal, a tourist from India, heading to Pokhara to paraglide with friends.
02:02Pokhara Tower, Yeti 691, descending through 12,500 feet.
02:09Captain Kamal KC is the senior officer and the pilot monitoring instruments on today's flight.
02:16Roger, Yeti 691, 12,500 feet.
02:21He's also a veteran of more than 21,000 flying hours.
02:28We had absolutely the utmost respect for Captain Kamal KC as he was a veteran in the Nipali skies.
02:37And he was quite a humble and knowledgeable guy as well.
02:41It's very clear. We'll be good for visual landing.
02:48Flying the plane from the left-hand seat is Captain Anju Katiwada.
02:53She's flown more than 6,000 hours.
02:58Captain Katiwada has a very special history.
03:00Her husband, he was a pilot with the same company.
03:04He was a first officer on the Twin Otter and he did crash and he died some years earlier.
03:11Katiwada decided to take up flying to honor his spirit so she'd become a pilot.
03:198,500 feet.
03:21While Captain Katiwada is an experienced commercial pilot, she has only 186 hours on the ATR-72.
03:30The ATR-72 is a turboprop twin-engine aircraft.
03:44It's a high-wing aircraft.
03:48It's a very stable, predictable and logical aircraft.
03:52And it's very good to fly here in the mountains and hilly regions of Nepal.
03:57Today's flight is a short 25-minute hop from Kathmandu to the tourist city of Pokhara.
04:12Yeti 691, expect to land on 12.
04:16Bugway 12, Yeti 691.
04:2015 miles from the airport, Yeti Flight 691 is cleared for the approach.
04:27Hey everyone, exciting times as we're headed to Pokhara's new airport.
04:32Sonu Jaiswal is live streaming from the cabin.
04:35The plan is to go paragliding in the Himalayan foothills with my buddies!
04:453, 1, 0.
04:47Captain Katiwada programs a heading for the approach to runway 1-2.
04:52You are in between the runway and the mountains.
05:01So you need to be very, very precise with your handling skills of the aircraft.
05:05Okay, visual, visual.
05:11Okay, visual.
05:14The pilots monitor their position carefully, keeping the plane clear of the mountains.
05:22Yeti Airlines 691 in sight.
05:25Report final, runway 1-2.
05:27Call you on final for runway 1-2.
05:30Yeti Airlines 691.
05:35Gear down.
05:39Less than two minutes from the airport, the pilots configure the plane for landing.
05:45Okay, from here you can go manual.
05:48Okay, stand by.
05:49Disconnect.
05:55Captain Katiwada disconnects the autopilot, then begins the first of two crucial turns to line up with the runway.
06:11Okay, flaps 30.
06:14Flaps 30.
06:17Continue descent.
06:19Okay.
06:23One minute from touchdown, the pilots run through the pre-landing checklist.
06:29Okay, landing gear.
06:30Down three green.
06:32Flaps?
06:3330.
06:37In the cabin, Sono J-Swell continues live streaming.
06:42We're getting pretty close now.
06:44As the flight gets closer to the ground, the landing seems trouble-free.
06:52But seconds from the runway, Captain KC realizes there's a critical problem with the engines.
07:04Captain Katiwada tries to power up, but the engines aren't producing any thrust.
07:18400 feet above the ground, the pilots face a critical situation.
07:19In the tower, the controller doesn't know that flight 691 is in any trouble.
07:31Yeti 691, runway 12, runway 12, cleared to land.
07:33There's no power, no power.
07:34No power.
07:35Add power.
07:36Captain Katiwada pushes the throttles to the limit.
07:40There's no torque.
07:41There's no torque.
07:42Okay, give it to me.
07:43Okay, give it to me.
07:44Captain Katiwada pushes the throttles to the limit.
07:48There's no torque.
07:49Okay, give it to me.
07:50Add power.
07:51Add power.
07:52Captain Katiwada pushes the throttles to the limit.
07:55There's no torque.
07:56Okay, give it to me.
07:57Captain Katiwada pushes the throttles to the limit.
08:02There's no torque.
08:03Okay, give it to me.
08:05The more senior captain takes control.
08:10Any 691?
08:19Two hundred.
08:20Any 691.
08:21Flight 691 is stalling.
08:26While Sonu Jaiswal live streams the unfolding disaster.
08:40What's happening?
08:45No!
08:46No!
08:47No!
08:48No!
08:49No!
08:50No!
08:51No!
08:52No!
08:54We're just getting hit.
08:55Wait!
08:56Wait!
08:57Wait!
08:58Wait!
08:59Not me!
09:00No!
09:01Wait!
09:02No!
09:04No!
09:05Wait!
09:06What!
09:07What?
09:08What?
09:09Nothing!
09:10No!
09:11No!
09:12I'm not.
09:13Not me!
09:14Yeti Flight 691 has crashed in one of the worst possible places.
09:27The Sethi River runs near to the airport through a huge gauze.
09:32That's where the plane crashed.
09:38The plane was completely destroyed in the impact.
09:42There was a huge flame burning.
09:48There was no possibility to find any survivor.
09:55The bodies of 71 of the 72 passengers and crew are eventually found and identified, including
10:03both pilots.
10:07This was the deadliest crash involving Nepali Airlines ever.
10:14What could have caused a commercial airliner to drop out of the sky just seconds before
10:20landing?
10:29When investigators arrive at the crash site of Yeti Flight 691, they face a devastating
10:36scene.
10:38The wreckage was scattered all over the place.
10:44The first impact was before the river, where the parts of the left wing was detached.
10:51Some parts were located on the bottom of the river gauze.
10:54The rest of the pathway at the saddle lever.
11:03Under the supervision of Nepali investigators, the wreckage, along with the black boxes and
11:09central processing card from the plane's computer, are sent for analysis to labs in France and
11:15Singapore.
11:16It's really not uncommon in an accident investigation to have to send something out for closer investigation.
11:34Nepali investigators wonder about Flight 691's orientation when it hit the ground.
11:39It looks like this is from the first point of impact.
11:46That's a flap from the left wing and an aileron tip.
11:52So the left wing must have hit the ground first.
11:59The plane crashes wing down.
12:01What that suggests to investigators is that the plane crashed out of control.
12:07You would never intend to have it be that way.
12:09You should always try and level it out and crash as close to a regular attitude as you
12:12can.
12:13Maybe the plane's stalled.
12:17You may be right.
12:21Check this out.
12:26It's gone viral.
12:32A witness had filmed the plane during the final moment of the flight.
12:43It appears that the left wing lost lift and dipped severely.
12:49It's at least an 80 degree left bank.
12:51It sure looks like a stall to me.
13:05When you see evidence that looks like a stall, you immediately start questioning what could
13:10have led to that.
13:11And you go back to what's going on during that approach.
13:21This is not an easy approach.
13:25They'd have to fly between the runway and the mountain and make two left turns before lining
13:31up with runway one, two.
13:34This is where the plane crashed.
13:36And just before the crash, they were beginning their final left turn.
13:42Did the pilots bank too far during one of the turns and stall?
13:49They would have had to go from zero to an 80 degree bank in a few seconds.
13:54It suggests there was a problem with the plane.
14:04You might want to focus and see if there's any smoking guns in the maintenance records.
14:08If there was anything wrong that somebody knew about, maybe they tried to fix it and
14:12it didn't get fixed.
14:16I've got maintenance records.
14:21Investigators go through the plane's records in search of any gaps in maintenance or inspections.
14:33Not seeing anything.
14:36Everything checks out.
14:39Maybe the controller knows something.
14:43Yeah.
14:45The air traffic controller may have heard something in their conversation with the pilots, picked
14:50up something that isn't really evident from the tape.
14:57Did you have visual contact with the aircraft?
15:04Did you see or hear anything suggesting a problem with the plane?
15:08No.
15:09I was flying normally when I had visuals with it.
15:12It was just out of sight right before the crash.
15:17Then I heard it.
15:19The explosion.
15:24Did the pilots say anything suggesting a problem with the plane?
15:31Nope.
15:32Not much.
15:33Okay.
15:35So...
15:36Do you know what happened?
15:42Not yet.
15:47In the early stages, you'd want to look at anything witnesses might have to say, anybody who might have seen, heard or otherwise noticed the crash.
15:54The controller offers little insight into why the plane stall.
16:17Then a witness to the accident comes forward.
16:18There?
16:19That's where you saw the plane?
16:20He had the credibility because he was an engineer.
16:21And you said that you saw the propeller spinning just before the crash?
16:24When you see a propeller rotating, it means it moves very slow.
16:25Otherwise, you cannot see it moving.
16:26Okay.
16:28The slow rotation comes forward.
16:29There?
16:30That's where you saw the plane?
16:31There?
16:32That's where you saw the plane?
16:33He had the credibility because he was an engineer.
16:34And you said that you saw the propeller spinning just before the crash?
16:38When you see a propeller rotating, it means it moves very slow.
16:47Otherwise, you cannot see it moving.
16:49Okay.
16:53The slow rotation of the propellers could indicate there was a problem with the engines that drive them.
17:02Quick update.
17:03Sounds like engine failure.
17:05Yep.
17:06We need to talk to the French about their engine analysis.
17:10Hello?
17:15Nepali investigators now joined the team from France to examine the wreckage of Yeti Flight 691.
17:27Engines are badly damaged.
17:30Can't tell if they failed in flight.
17:36Most of the engines were consumed by fire, so they couldn't learn definitively whether they were producing power.
17:45Look at that prop.
17:49It looks feathered.
17:50It looks feathered.
17:51It looks feathered.
17:56When propellers are feathered, their edges face forward and cannot produce thrust.
18:13It's like putting your car in neutral position.
18:18You can push on the gas as much as you want, but nothing is going to happen.
18:22It's actually stuck in a feathered position.
18:31Okay.
18:39This one moves freely, but it could have moved on impact.
18:48This one is stuck too.
18:52So, two of them were in the feathered position when they hit the ground.
19:00Normally, propellers are feathered on the ground after shutdown.
19:04That prevents them from spinning in the wind and damaging the engine.
19:09There is, however, one exception.
19:12An automatic feathering unit will feather that propeller immediately as soon as an engine failure is detected.
19:18Perhaps faster than the pilot can do it.
19:23Were the props feathered automatically in flight due to engine failure?
19:28Investigators download the data from Flight 691's multi-function computer to find out.
19:35The multi-function computer stores information about the automatic feathering unit in its memory.
19:42They are going to be able to learn whether the auto feather unit feathered one engine or both engines.
19:49It never activated.
20:03If you learn that the auto feather system didn't feather the propellers, that immediately raises the question, who or what did?
20:10Were the propellers feathered manually?
20:16Investigators consider a crucial piece of wreckage recovered from the scene, the central control pedestal.
20:23The central pedestal is located between the pilots.
20:28And here you have the power levers.
20:30You have the flaps lever.
20:32And you have the condition levers, which controls the propellers.
20:35The flaps are stuck at 30.
20:39That's where they should be for landing.
20:42Condition levers are moving freely.
20:47Doesn't tell us much.
20:53Hmm.
20:54Look at this.
20:59Witness mark.
21:04You're looking for witness marks, the marks that one aircraft component makes against another at the time of impact.
21:13And those marks will suggest, in the case of the central control pedestal, where the controls were positioned at impact.
21:23The witness mark suggests that the pilots could have put the left lever in the feathered position.
21:31Maybe some other debris caused the witness mark.
21:34There's no witness mark for the right condition lever.
21:41Were the propellers feathered by the pilots?
21:44Or did the witness marks occur on impact?
21:48We're going to need the flight data recorder download to settle this.
21:52The flight data recorder doesn't record the propeller blade angle.
22:01But it does record certain parameters that let investigators infer whether the propellers were feathered, and if so, when.
22:09They find evidence that the pilots feathered the props one minute before the crash.
22:30When the propellers are feathered, the torque drops, and the propeller's RPM speed drops.
22:40That's what the witness was able to see when he reported spotting the individual propeller blades.
22:47How did they make that mistake?
22:57What was going on in the pilot's mind?
23:00What was going on in the cockpit?
23:02What's happening?
23:17Pick it up 24 minutes into the flight.
23:19Right before the propellers were feathered.
23:23Investigators listened to the cockpit voice recording from Yeti Airlines Flight 691 to understand why the pilots feathered their propellers when they did.
23:34Okay, from here you can go manual.
23:36Okay, stand by.
23:41Disconnect.
23:44Okay, flaps 30.
23:46Flaps 30.
23:49Continue descent.
23:51Okay.
23:52Stop, Samson.
23:55Where are we at here?
23:57Time is 10 56 35.
24:04According to the FDR, the flaps did not move to 30 at this point.
24:11But this is when the props were feathered.
24:14The FDR shows that when the pilot flying commanded flaps 30, the flaps didn't move.
24:23But at the same moment, the prop RPM decreased and torque went to zero.
24:28The pilot has pretty obviously feathered the engines instead of moving the flaps.
24:35They must have mixed up the flap levers with the condition levers.
24:49And Captain Casey was the pilot monitoring.
24:55How could a captain make that mistake?
24:58In most airline accidents, pilot error is a factor.
25:07That can be because of inadequate training, experience.
25:12It can be because of too little rest.
25:17But there can also be other factors impairing their decisions.
25:21Here you go.
25:28The team reviews results from the pilot's toxicology tests.
25:35Nothing on Captain Katiwata.
25:42Same with Captain Casey.
25:44Maybe they weren't adequately rested.
25:53According to the airline's records, both pilot schedules were within guidelines, suggesting adequate rest.
26:00And their medical certificates are current.
26:03They conclude that something other than impaired judgment caused the pilots to feather the props by mistake.
26:10At this point, you'd have to wonder what might have been going on in the cockpit that would lead him to be distracted into setting the propellers to feather instead of setting the flaps for landing.
26:24Did the location of the condition levers on the pedestal play a part in the captain's error?
26:30They examine an ATR-72 pedestal.
26:33I reach over for the flaps, but I put my hand on the condition lever instead.
26:46The flap lever and the condition levers are very close together on the pedestal.
26:52I want to move the flaps to the 30-degree position, but instead, I move the condition lever to feathered.
27:08The flap and condition levers have the same range of motion and stop in similar positions.
27:14It's not a stretch that they could have mixed up the levers.
27:20And don't forget, Captain Casey was where I'm sitting.
27:25Right.
27:26Mercy and memory is very important for a pilot because you can do sequences without being conscious about it.
27:39But when you move to another seat on the other side, certainly that flow is disturbed because now you have to use the opposite hand.
27:50Oh, that feels a lot less natural.
27:52And much easier to mix up.
28:01Okay, flaps 30.
28:04Flaps 30.
28:06Continue descent.
28:09The pilot monitoring moved the condition levers instead of the flap lever.
28:16That should be impossible, but it has happened before.
28:20I once asked for flaps and the pilot monitoring selected the gear down.
28:28And those levers are far apart.
28:33Still, it's hard to imagine looking at these levers that you'd get them confused.
28:39True.
28:40Maybe he wasn't looking at them.
28:49Why would an experienced captain not check which levers he was moving?
28:53Why would an experienced captain not check which levers he was moving?
29:03Okay, visual, visual.
29:05Okay, visual.
29:06Investigators return to the voice recording of Yeti Airlines Flight 691 to determine if the captain's attention was elsewhere when he selected the wrong levers.
29:18Okay, make sure you stay between the mountains and the runway.
29:20They revisit the moment just before the propellers were feathered.
29:26Keep your power nose up.
29:28Keep visual with the tower.
29:30Don't go too far.
29:32Okay, copy that.
29:33Okay, stop for a second.
29:37He's giving her a lot of instructions.
29:42Maybe that's the distraction.
29:46But she's a very experienced pilot, so why is he doing that?
29:50When you're giving instruction, that's an added mental stress, it's an added cognitive load.
29:58It's very distracting.
30:01Let's start from the top.
30:04Poker Tower, Yeti Airlines 691.
30:09Yeti Airlines 691.
30:12Tower, Yeti 691.
30:15Descending through 12,500 feet.
30:17Roger, Yeti 691.
30:2112,500 feet.
30:23Expect to land on runway 30.
30:26Runway 30, Yeti 691.
30:31They discover that Flight 691 was initially cleared to land on a different runway, runway 30.
30:39But eight minutes later, there's a change of plan.
30:43If traffic permits, let's land on runway 12.
30:47Then you'll be approved for runway 12 without any instructor-pilot supervision.
30:52Okay, runway 12.
30:54Not only is he monitoring the flight, he's approving her to land at Pokhra's new airport.
31:01Investigators discover Captain Casey was instructing pilots on how to land on both runways at the new airport.
31:10I flew with Captain Kamal Casey just two days before for my route qualification into Pokhra International Airport.
31:20But why runway 12?
31:22But why runway 12?
31:26You'll be approved to land in both directions.
31:29Copy that.
31:30Copy that.
31:37Okay, stop it.
31:39So Captain Khatawada is cleared for runway 30.
31:43And Captain Casey decides much later in the game he's approving her for runway 12.
31:48For runway 12?
31:51Captain Khatawada had landed on runway 30, but never 12.
31:57Runway 30 is a straight-in approach.
32:00On runway 12, you follow a narrow track next to the mountains.
32:06And you turn left twice to line up with the runway.
32:13So Captain Casey put Captain Khatawada on a more difficult landing.
32:23Runway 12 was a challenging approach for a pilot with just 185 hours on the air.
32:28Did Captain Casey properly prepare Captain Khatawada for the difficult approach to runway 12?
32:40The best way to prepare a pilot for such an approach would be to do a proper briefing.
32:47Maybe they have photos, videos, simulated training if available.
32:54Investigators examine Captain Khatawada's training records.
32:59She spent no time in the simulator training on runway 12.
33:04What about a formal briefing?
33:07There's no documentation related to training on 12.
33:11I've got Captain Casey's flight history.
33:15Was Captain Casey even qualified to train others for landing on runway 12?
33:21Turns out he had only landed on 12 twice.
33:24A bit of experience, but not enough.
33:31Because of his low experience and also Khatawada's low experience on the aircraft.
33:39I find that a bit strange.
33:42I wonder if it's even possible to do a stabilized visual landing using that approach.
33:48A stabilized visual approach is one that's conducted with the runway in sight, at a normal rate of descent, with landing flaps and landing gear down, at the proper airspeed and with all checklists completed by a certain point.
34:13By a certain point.
34:16There's just over one mile between the completion of the last turn and the runway.
34:21That's going to give you just over 30 seconds from lining up to landing.
34:27It's very tight.
34:31A visual landing can increase the workload because they have to make tiny adjustments all the way through the pattern.
34:42Let's see how they handle the workload.
34:47Okay, make sure you stay between the mountains and the runway.
34:51To understand how the pilots dealt with the final approach to runway 12, investigators return to the CVR.
34:59Keep your power nose up.
35:01Keep visual with the tower.
35:04Don't go too far.
35:06Okay, copy that.
35:08Remember you need to make an early turn here.
35:12Okay, a beam tower.
35:14Gear down.
35:16Gear down.
35:22Can I fly it manually?
35:23Wait.
35:25Wait, not yet.
35:26Keep going straight.
35:28After flaps 30, then you're good to go manual.
35:32Hold on.
35:34Captain Casey is so focused on pointing out landmarks outside the cockpit, he's not paying attention to what's happening inside the cockpit.
35:41It's normal to let the less experienced pilot fly the aircraft and the most experienced pilot do the analysis.
35:54Okay, flaps 30.
35:57Flaps 30.
36:02Continue descent.
36:04Okay.
36:05He probably didn't even look down to see what lever he was moving.
36:13But there was still an opportunity to catch the mistake when they do the landing checklist.
36:23The before landing checklist was an opportunity for him to look down at that control pedestal and see that he had moved the condition levers into Feather.
36:32I'm almost certain they could have recovered right up until the last few seconds.
36:40Did the pilots' failure to follow their checklist ultimately determine their fate?
36:45Nepali investigators continue listening to the CVR of Flight 691 to learn whether the pilots followed the proper procedures before landing.
37:01Before landing checklist.
37:02Okay.
37:08Landing gear.
37:10Down three green.
37:11Flaps?
37:1230.
37:13Wait.
37:15Captain Kariwata said the flaps are at 30 but according to the FDR they're still set at 15.
37:23Neither pilot checked the flap settings.
37:25If Captain KC saw that the flaps were not at 30, he may have realized he had moved the wrong lever.
37:35Power management?
37:37Takeoff.
37:38TLU?
37:40Low speed.
37:41Icing. AOA.
37:43Check.
37:44External lights on?
37:45On.
37:46Complete.
37:48They rushed it.
37:52The before landing checklist was done very fast.
37:55Like bam bam bam bam bam.
37:57And I doubt any of them looked at the flap setting.
38:00They just answered by memory.
38:02Oh.
38:04And with the props feathered, there should have been warning lights.
38:08Why didn't they figure it out?
38:09Why didn't they figure it out?
38:21When the propellers are feathered, they're no longer providing power to the generators.
38:27An aural and visual ELEC warning alerts the pilots that they're losing electrical power.
38:34What is this?
38:35Huh?
38:36ELEC is on CAP.
38:41The ELEC light comes on to warn the pilots, hey you've got a big electrical problem.
38:46Checked.
38:48Check.
38:49Someone clicked off the warning.
38:51They clicked off the warning without figuring out why it even came on.
38:57It's hard to tell why Captain Kamal KC responded checked to the electrical light.
39:04Check.
39:06Would you pull out a quick reference handbook and start working a long electrical failure procedure?
39:11Or would you recognize, hey I'm landing in less than 60 seconds.
39:15Let's just bring the plane in and deal with the problem on the ground.
39:19We just continue, right?
39:21Yes. Continue turn.
39:22Continue turn.
39:28What's that click about?
39:34FDR data shows this is where the flaps goes to 30.
39:37So he notices the flap is not set at 30 and corrects it.
39:49And with so much workload, all he sees is the flap lever and doesn't notice that the propellers are feathered.
39:55When your workload increases, you get tunnel vision and you see less.
40:02That makes it very difficult because now you only focus on one thing.
40:07Okay, but why doesn't he figure it out when the engines have dropped to idle?
40:12Seconds from the runway, Captain KC realizes there's an issue with the engines.
40:24There's no power.
40:25There's no power.
40:27There's no power.
40:29Add power.
40:33Even though the pilots see the engines are at idle, they are still unaware that the propellers are feathered.
40:39There's no power.
40:40No power.
40:41Add power.
40:45There's no torque.
40:46Okay, give it to me.
40:49In desperation, Captain KC takes control of the plane.
40:53You're landing, sir.
40:55No power.
40:56Torque indication zero.
40:59200.
41:028691.
41:04What's happening?
41:09He decided to fly the plane rather than try to diagnose the problem.
41:33One single glance around the cockpit could have told him that he had feathered the propellers.
41:39The final report of the Nepali Accident Investigation Commission concludes that the most probable cause of the accident was the inadvertent movement of both condition levers to the feathered position in flight.
41:59What strikes me about this is that it was a very normal situation.
42:06The only thing that went between success and failure was the slip of a hand.
42:12The proximity to terrain and sharp turn required to land on runway 12.
42:23Before landing checklist.
42:24Combined with a high workload and a lack of appropriate training all contributed to the crash.
42:31After the accident, Yeti Airlines tests the approach in the simulator with their pilots.
42:40Most of our pilots were not able to land on runway 12.
42:45Either they were high on approach or they were fast on speed.
42:50Yeti Airlines stops flying into runway 12 until they are able to establish a safe visual procedure and retrain their pilots.
43:02The Commission recommends that the Civil Aviation Authority of Nepal ensures that a stabilised flight path is approved before allowing commercial operations at a new airport.
43:18After the accident, the victims of Yeti Air Flight 691 are mourned by a nation.
43:24And fellow pilots remember their colleagues.
43:27For Captain Kamal Casey, I just want to remember him when he was alive and he was there with us.
43:39Captain Khatiboda, I respected her a lot.
43:45She will be remembered as an elder sister.
43:50And there is going to be always a void in the airlines that she is not there anymore.
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