Mayday (2013) s17e10 Episode Script
The Lost Plane
A regular commercial flight to an extraordinary part of the world.
A lot of tourists fly in just for the scenery.
Thai Airways 311 is bound for Kathmandu.
But it never arrives.
Thai 311, Kathmandu.
Please report your position.
Until the aeroplane is found, it's difficult to figure out what might have happened.
This is where we search.
A high-altitude trek leads investigators to one of the most remote places on Earth.
You couldn't tell that you had an Airbus A310 aircraft there.
You couldn't even tell you had two engines.
How can they ever hope to piece together what happened? Right away, you knew you were really gonna be in a difficult situation.
It is mid-summer in the Himalayas.
Monsoon season, when shifting winds and sudden rains sweep across the jagged mountain landscape.
Just above the awesome peaks flies Thai Airways flight 311.
The pilot flying is Captain Preeda Suttimai.
His first officer is Phunthat Boonyayej.
I will never get tired of seeing these mountains.
It truly is an extraordinary sight, brother.
The flight's 99 passengers are a mix of Nepalese nationals and international tourists all headed to Kathmandu.
Kathmandu is a popular tourist destination.
It's a mountainous airport and a lot of tourists fly in just for that, for the scenery.
The Thai Airways plane is an Airbus A310, a medium-to long-range twinjet.
The A310 overall is a fantastic aeroplane.
It has a range of eight hours and it can carry 20 tonnes at a decent altitude.
The flight from Bangkok to Kathmandu is expected to take roughly 3.
5 hours.
The Nepalese capital lies at more than 4,500ft above sea level.
The approach requires navigating near some of the world's highest mountains.
Kathmandu, Thai 311.
Request descent.
Uh, Kathmandu, Thai 311.
Do you read? The first attempts that the flight crew had with air traffic control, they called three times and got no response at all.
Kathmandu, Thai 311.
Do you read? The acoustics were not very good.
There was a lot of echoing on the frequency.
Maybe it had been caused by the mountains.
Kathmandu, Thai 311.
311, Kathmandu.
Go ahead.
Finally, the Nepalese controller hears the call.
Request descent.
Thai 311, we have negative traffic at or above flight level 150 within our juris Except one in Nepal at 206.
You are cleared for descent.
The controller, he was relatively inexperienced.
He had nine months' experience.
Um, you know, he's not a complete rookie but at the same time, he's got a lot to learn yet.
Ladies and gentlemen, we will soon begin our descent into Kathmandu.
Please stow away your tray tables, raise your seat backs and fasten your seatbelts in preparation for landing.
The flight is now about 30 minutes from its destination.
Lots of clouds.
Let's go through.
Kathmandu's Tribhuvan International Airport is one of the most challenging in the world.
The mountains that tower above the capital force pilots to descend much more steeply than at other airports.
When I look at the approach that the aircraft was going to be flying going into Kathmandu, I'm definitely struck by the steepness of the approach itself and the gradient of the terrain in the area.
Go ahead.
Would you request for runway 02, please? Thai 311, request 02.
Thai 311, confirm requesting 02.
Confirm.
The pilots have requested a straight-in approach from the south to runway two.
It will keep them clear of high mountains north of the airport.
But as they get closer, things change.
Thai 311, Kathmandu.
Go ahead, Thai 311.
Thai 311, for your information, runway 02 not available due to poor visibility and heavy rain toward that side.
You'll have to take runway 20.
Sudden bad weather means the only approach now available is from the north.
It requires circling north of the airport to land on the opposite runway, a manoeuvre the captain does not want to make.
We need runway 02 for the straight-in approach.
You'd be challenged at the notion doing a circling approach in a mountainous environment.
It's one thing to do it over an island, say, in the sea without any obstacles.
It's another thing to do it surrounded by mountains.
I guess we can't make it, brother.
Please check the field to Calcutta.
The captain decides to abandon the landing and divert to an airport in India.
Fuel.
We got enough to get to Bangkok.
And for Calcutta, how much do we need? 18? 14? 42? For passengers, diverting to Calcutta would mean landing more than 400 miles away from their destination.
Thai 311, I've just confirmed that runway 02 is now also available.
Report 25.
Wait a minute.
It seems the unpredictable weather has changed again.
It's good news.
Kathmandu, Thai 311.
Confirm runway 02 available? - Confirmed.
Runway 02 is now available.
- That's lucky.
The straight-in approach from the south is once again clear.
But the plane is now too close to the runway to descend safely.
They were a little bit high for the position that they were at in relation to the airport.
Kathmandu, Thai 311.
We cannot make approach now.
We will need to turn back to Romeo and climb to 18,000ft and start our approach again.
The captain decides to turn around and try again.
It should give him the distance he needs for a safe, controlled descent.
Using the Flight Management System, First Officer Boonyayej looks up a navigational waypoint, called Romeo, to restart their approach.
But there's a problem.
The system won't lock in the flight path to Romeo.
It disappeared.
It's Romeo 27, isn't it? Ro-me-o.
Kathmandu, what is the visibility? Thai 311, standby for tower observation and visibility.
Flying in dense cloud, the pilots' view ahead is extremely limited.
They want to know when they can expect to see the airport.
- Level change.
- Terrain.
Terrain.
Pull up.
A ground proximity warning suddenly begins to sound.
Pull up.
Pull up.
Airspeed low.
- Turn back.
Turn back! - It's false.
It's false.
Terrain.
Pull up.
Don't sink.
- Terrain.
Terrain.
Pull up.
Pull up.
- Oh, my god! Thai 311, please report your position.
Thai 311, Kathmandu.
Please report your position.
In the mountains of Nepal, a search is underway for Thai Airways flight 311.
The Airbus carrying 113 people vanished on approach to Kathmandu.
Nepal has moved quickly to set up a Royal Commission of investigators.
This is the airport.
Flight 311 was coming in from the south, here.
Until the aeroplane is found, it's difficult to figure out what might have happened.
This is where we search.
They search an area covering dozens of square miles to the south of Kathmandu.
And the search, of course, started in the south because it came in from the south.
A methodical search eliminates territory sector by sector.
Where is this thing? The plane is nowhere to be found.
Time is of the essence.
The unpredictable Himalayan weather could bring heavy rains at any moment, making the search all but impossible.
As the mountain search continues, investigators interview air traffic control, hoping for any kind of lead.
We don't have radar here, so I can't help you with the aeroplane's location.
A radar is a line of sight tool.
It doesn't penetrate through mountains or anything like that.
So in a mountainous area like Kathmandu, your radar coverage would be limited to some degree because it would be blocked by the mountains themselves.
I just rely on what the pilots tell me.
In a non-radar environment, they have a mental picture, and that picture is really painted by the words that the pilot reports to them.
They don't have an exact location.
It's almost like working blindfolded.
They were going to restart their approach.
Their last reported position was here, 14 miles to the south of the airport.
Kathmandu, Thai 311.
We cannot make approach now.
We will turn back to Romeo and climb to 18,000ft to start our approach again.
To redo the approach, they would have to turn back towards the south.
There was one thing.
At one point, they mentioned a technical fault.
But a few seconds later they said they were fine.
A mysterious technical fault raises suspicion.
But at this point, there's no way of knowing if it played any role in the plane's disappearance.
They knew the aircraft had some technical problem.
That's what they were told.
You didn't know whether it was a radio fault, a navigation system fault, so we wondered what it was.
It's been almost 48 hours since Thai Airways flight 311 disappeared in the Himalayas.
Investigators have yet to find the aircraft.
But now they're about to get an important break.
Local villagers report that they found aircraft debris north of Kathmandu.
Some people where the aeroplane crashed had heard about it, had heard the crash and they couldn't communicate with anybody as to where it went 'cause they didn't have the means to do so.
Are you sure you don't mean down here, to the south of the city? Investigators can't quite believe it.
The reported crash site is nowhere near the area they've been searching.
I don't think they ever in their wildest imagination thought the aeroplane was north of the airport.
North of Kathmandu, near the border with Tibet, the Himalayan peaks soar to an altitude of 20,000ft.
These northern summits are the reason almost all planes approach Tribhuvan Airport from the south, where the mountains are closer to 8,000ft.
Send out the helicopters.
Tell them to start searching to the north of the airport.
Later that day, 27 miles north of Kathmandu, search crews find the remains of Thai Airways flight 311.
The point of impact is a steep rock face more than 11,000ft up the side of a remote mountain.
It hit, essentially, a vertical rock face and then the whole aircraft just tumbled down into a valley.
There was some small evidence of fire, but mostly just total destruction of the aircraft.
None of the 113 people on-board have survived.
It immediately created mysteries as to what might have happened, why the aeroplane got to a place that it was not expected.
The challenge for investigators is unlike anything they've encountered before.
The terrain is so extreme, helicopters can't land near the impact zone.
The team will have to trek more than 3,000ft up from the base camp to reach the wreckage.
It's a treacherous five-hour hike.
OK.
I gotta stop.
It's a dangerous area.
You had to be very, very careful.
At high altitude, you tend to end up with hypoxia.
It isn't long before the mountains let it be known just how dangerous they can be.
What happened? What's going on? One of the investigators died.
A British investigator for Airbus suffers fatal complications from hypoxemia, a lack of oxygen in the blood due to thin air at high altitude.
It's bad enough that people die in the accident but you don't want other people dying trying to solve the accident or recover things from the accident site.
And so that was a shock.
It's now brutally clear to everyone, on this mission, the stakes could not be higher.
Deep in the Himalayan mountains, Nepal's Accident Investigation Commission makes its way toward the Thai Airways crash site.
The team includes experts from around the world, including Canada's David Rohrer.
You're there to hopefully find something to prevent recurrence, to save somebody else from having that same tragedy in their lives or have a similar outcome.
That's why you're there.
Rohrer is confronted with a scene of total devastation.
The level of destruction was enormous.
You couldn't tell that you had an Airbus A310 aircraft there.
I mean, you couldn't even tell you had two engines.
The first big question they have is, "How did Thai Airways flight 311 end up here?" The Airbus should never have been flying north of the airport.
Searchers soon find the cockpit voice recorder.
But that won't reveal the flight path.
Bring that to base.
Investigators already know the airport has no radar data.
Their best chance of discovering how the plane reached this fatal impact zone is to find the flight data recorder.
Right away, you knew that if you didn't have the FDR then you were really gonna be in a difficult situation in terms of trying to determine cause or probable factors.
- Still no sign of the FDR? - No.
Unfortunately not.
The intensive high-altitude effort has already killed one team member.
Investigators know that their time on the mountain will be limited.
Right over there.
An airport hangar in Kathmandu is the final stop on a long journey for wreckage collected from the mountainside.
The Sherpas would bring down the pieces that we identified down to the landing zone.
Then the Nepalese army in their helicopters would put them in nets and then sling them down to the hangar at the airport.
With still no word on the plane's flight data recorder, investigators review the A310's maintenance records.
In any investigation, you don't just sit and wait for the recorders.
You start doing work right away.
For example, were there any problems with the aircraft before the accident? They already know that the Thai Airways pilots reported an unknown technical fault to air traffic control.
It's a red flag and there's so many different areas that could be called a technical fault.
You know, was it a configuration issue? Was it a power issue? Was it a landing gear issue? It just opens up Pandora's Box of what it can be.
Hey, look at this.
The day before the flight, there was a circuit breaker failure on the plane.
There was a recurring problem with the XP-205 bus.
And that bus was related to navigation equipment, so we were kind of thinking, "Well, perhaps we better look at that in more detail.
" The XP-205 bus carries electrical power to several important systems, including the plane's navigation system.
Maybe the bus failed while they were in flight.
It's possible.
A malfunction in the navigation system could explain the location of the crash.
If that bus failed, it would wipe out the co-pilot's electric instruments, which would show his position and his navigation.
That would be pretty critical.
But in order to prove their theory, they'll have to track down the XP-205 bus amidst piles of burnt and twisted debris.
It's hard to tell what we're even looking at here.
Given the destruction of the aircraft, very difficult to track down those types of technical issues.
As team members comb through the wreckage, the investigation takes an unexpected turn.
Excuse me.
Can I help you? During the investigation, one of the family members were asking for a circuit board, just because it somehow would link them to their loved one.
The unusual request leads to an incredible find.
That's when we actually found the internal mechanism of the recorder we were missing, which was quite amazing.
The FDR should provide crucial data on the plane's speed, direction, and altitude throughout the flight.
You always hope that luck is on your side, that things will happen to your benefit.
And those are the kind of moments you really hope for as an investigator.
It's the breakthrough they've been waiting for, evidence that could reveal how a plane flying south of the airport ended up slamming into mountains to its north.
Ready? OK.
Start it up.
The cockpit voice recorder from Thai Airways flight 311 is finally ready for analysis.
Lots of clouds.
Let's go through.
Investigators hope to hear something that might help explain why the Airbus hit a mountain at over 11,000ft.
Thai 311, Kathmandu.
Go ahead.
Would you request for runway 02, please? Thai, uh, 311, request 02.
- Thai 311, confirm requesting 02? - Confirm.
As they initiate their descent, all seems normal.
I guess we can't make it, brother.
Please check the fuel to Calcutta.
But as the captain considers diverting to Calcutta, the atmosphere in the cockpit seems to change.
Fuel.
We got enough to get back to Bangkok.
And for Calcutta, how much do we need? 18? 14? 42? He's really getting frustrated with his first officer.
I got the impression that thethe answers from the first officer were not what the captain was looking for.
They weren't communicating properly with each other.
Thai 311, I've just confirmed that runway 02 is now also available.
Report 25.
Wait a minute.
Kathmandu, Thai 311.
Confirm runway 02 available? Investigators then notice something else out of the ordinary.
Confirmed.
Runway 02 is now available.
Request surface condition, please.
Wait - wait a minute.
Stop.
The pilot on the radio is not the first officer.
It's the captain.
Why was the captain speaking with the controller? As the pilot flying, the captain should never have been speaking with air traffic control.
It's up to the first officer, as the non-flying pilot, to do the communication.
But it didn't unfold that way.
Normally, division of duties in a cockpit's very important in sharing workload.
But in this case, I noticed that the captain was, in many cases, taking over the radio transmission work.
Speed brake in.
Flap 15.
Speed brake in.
Flap 15 selected.
As they keep listening, they hear the captain's frustration grow.
Damn it! The flaps cannot be extended.
The flaps would not extend to full configuration, which, for the Kathmandu approach, is essential.
It's too late to make a landing.
It's too late.
We can request a return.
Damn it! Kathmandu, Thai 311.
Request to maintain 10,500 and request to go back to Calcutta due to technical.
It's now clear that the technical problem has nothing to do with a circuit breaker.
It's the wing flaps.
They won't extend to 15 degrees.
When they went to 15 and 15, of course they didn't get 15 and 15.
They got the one chime and they had a flap fault.
But just how serious a problem is it? Will it affect the captain's ability to control his plane? Hey.
The flaps have extended.
The recording soon tells them that the flap issue is quickly resolved.
They did cycle the flaps.
They did correct the problem.
Uh, back to normal now.
Can we make a left turn to Romeo? Understand operation normal.
And you'd like to make an approach? Affirm.
Affirm.
The situation appears to be stabilising.
Thai 311, clear Sierra approach.
Report 10 DME leaving 9,500.
But the captain's frustration soon returns.
We can't land at this time.
We have to make a left turn back to Romeo and start our approach again.
Communication with ATC was anything but great.
It was fragmented.
It was unclear.
Thai 311, go ahead your DME distance.
We are nine DME, 10,500ft.
Answer, please.
Answer, please.
Repeated requests to return to Romeo were pretty much unanswered.
Investigators now wonder Kathmandu, Thai 311.
Can we make our left turn back now? .
.
does the Thai Airways crew keep flying towards the mountains because they don't have clearance to change course? We'll climb and turn to the right.
But, despite lacking clearance, the captain takes matters into his own hands and turns his plane right, heading back to the start of the approach.
They're all gone.
They've disappeared! Moments later, there is more uncertainty in the cockpit.
It's Romeo 27, isn't it? Ro-me-o.
Also, the captain seemed to be getting frustrated with the co-pilot's efforts to put things in the navigation system.
This thing failed again.
Why is he having such a hard time inputting the waypoint? Then, investigators hear a surprising question from the first officer.
Are we going north? The co-pilot said something like, "We're going north, huh?" With that inflection like it's a mitigated type question.
The recording presents a troubling contradiction.
Though clearly frustrated with air traffic control and with his co-pilot, it seems the captain managed to turn south away from the mountains.
Yet, minutes later, they hit a wall to the north.
Terrain.
Terrain.
Pull up.
- Turn back.
Turn back! - It's false.
It's false.
- Pull up.
How they ended up slamming into a mountain they were supposed to be flying away from remains a mystery.
- Terrain.
Terrain.
Pull up.
- Oh, my god! In Nepal, investigators have ruled out the possibility that a faulty circuit breaker caused the Thai Airways 311 disaster.
Had the XP-205 bus failed, it would have fired off some warning chimes, which I'm sure they would have talked about, which they didn't.
And so I think that that was probably the main reason we discounted it as a factor.
They wonder if the work records of the two Thai Airways pilots can shed any new light on the investigation.
The captain's record reveals he was a highly trained pilot who had flown to Kathmandu many times.
He was impressive, and I think everybody in the company had identified him as a person who was going to go right to the senior levels of the company.
The co-pilot was older than the captain.
He had a lot of experience, as well.
The first officer has flown into Kathmandu 14 times in the last year.
But as investigators look more deeply into the first officer's record, they make a surprising discovery.
Thai Airways, they categorised you based on whether you were gonna be captain material or whether you were going to be first officer material only.
Interestingly enough, in their assessment, they categorised for the first officer in this case that he would not be captain.
I've always thought that if you tell somebody you're limited, "I will hire you but you're limited," then, well, maybe they'll fulfil that prophecy.
It still doesn't explain how they ended up way up here to the north.
Flight 311 flew 27 miles north of the airport into airspace commercial airliners normally avoid at all cost.
Is that the data from the FDR? Great.
With the FDR data now recovered, investigators have their first chance to analyse the plane's deadly flight path.
'Cause recorders will give you latitude and longitude.
It gives you a nice track as to where the aeroplane went.
First, let's have a look at what they were intending to do.
Can you pass me the published approach? Thai Airways' approach to Kathmandu is from the south.
The crew wanted to land on runway two.
OK.
Roughly here is where they would have decided on the missed approach.
This is where they were supposed to go.
Let's see what they actually did.
The data shows flight 311 proceeding north towards Kathmandu.
Everything seems to be in order.
And right here, they're looping around to restart their approach, right? Alright.
They were supposed to level out.
They just kept turning.
Instead of straightening out and heading to Romeo, flight 311 does a complete 360-degree turn.
When I saw it, I was you know, I was amazed because I couldn't understand why they would want to do that.
It just doesn't make any sense.
Why the Airbus flew in a complete circle back on a collision course with mountains north of the airport is a mystery investigators must solve in order to understand why 113 people died aboard the Thai Airways flight.
- Ready? - Ready.
Fire it up.
In search of answers, they turn to a flight simulator.
In terms of simulator testing, the one thing that it allows the investigators to do is to replicate what happened and understand what the crew would see or any other problems that they would face.
The captain just took over communications with the controller.
Yeah, OK.
Kathmandu, Thai 311.
Confirm runway 02 available? At this point, the captain is flying the aircraft, monitoring the instruments, and speaking to the controller, all on one of the steepest, most difficult descents in aviation.
Speed brake in.
Flap 15.
Speed brake in.
Flap 15 selected.
Damn it! The flaps cannot be extended.
The flap issue is temporary.
But time spent resolving it forces a delay.
They can no longer make the straight-in landing.
Let's see.
OK.
No.
We are too high and too close for the approach.
The only choice is to circle back and do another approach.
The controller hasn't given clearance.
He keeps asking for the aircraft's altitude and distance from the airport.
Hang on.
We are getting very close to the mountains, right? We need to make a turn soon.
The autopilot takes the plane to a selected heading in the shortest way possible.
In this case, that would mean turning to the left.
The controller said there's traffic to the left.
OK, there is a lot going on here right now.
And he still hasn't cleared you to go back to Romeo.
Needing to turn before he reaches the mountains north of Kathmandu and with traffic on his left, the captain decides to override the autopilot.
We'll climb and turn to the right.
He can turn right by turning the heading knob incrementally in the same direction.
The aeroplane was turned most likely by changing the heading bug.
In other words, the captain has that option.
He just turns a heading selector and the aeroplane will turn.
- Watch your turn.
You're centre level off.
- Oh.
Yeah.
Right.
The climb, turn, descend with an autopilot, that's tough to do.
And he was doing all of that in the turn.
- OK.
You're starting to fly south now and should straighten out.
- Yes.
But he gets yet another call.
The controller tells him to lower the altitude to 11,500ft due to traffic in the area.
OK.
Thai 311, descend to flight level 11,500.
It started to really become apparent that, you know what? With all the distractions, with all the workload that the captain had that eventually, you know, the monkey climbed on his back and he took on the whole load of the operation.
Investigators are close to a breakthrough.
And this is the moment they should have stopped adjusting the heading.
The simulation gives them a sense of the mounting pressure in the Thai Airways cockpit.
An extremely busy captain flying a challenging approach attempts an improvised right turn.
He's trying to do too many things at once.
He's asking to go to a point, he's trying to fly the aeroplane on the autopilot and he's starting to lose the 3D picture that he has in his head where he is.
Without realising it, he turns the heading knob too far.
He turned it one too many times and did a full circle.
Each time he has to reach up and change his heading, he has to take his eyes off the ball.
What's the one thing that we never do? Is take our eyes off the ball.
Well, each time he reaches up to select a different button, he takes his eye off of the screen.
The captain took on too much himself where the point he was distracted from his primary task, which is to navigate the aeroplane.
Investigators finally understand how the plane ended up heading in the wrong direction.
But they still wonder why the crew didn't notice the mistake in time.
After he did the turn, they kept flying north for more than five minutes.
As the pilots head toward disaster, they struggle to input the Romeo waypoint.
Their frustration with the flight computer should be a warning sign.
Romeo is now behind them.
How could they not notice? Why the Thai Airways crew failed to notice that they had turned their plane 360 degrees back towards the towering Himalayan mountains is one of the last mysteries investigators want to solve.
The team tried to understand as to why the crew continued to the north.
What cues could they have got and why did they ignore those cues? Take a look at this.
There are no cardinal points on the compass.
A close look at the cockpit compass reveals a possible explanation.
The instrument lacks the usual direction markers, N-S-E-W, for North, South, East and West.
It had just numbers.
I think if there had been a big 'N' on top of the compass the whole time, it might have made a difference.
When you're fully confident about where you're going, at what altitude, in what direction, when you think you have the mental picture, but yet you don't actually have the mental picture, you're situationally unaware of where you are.
You know, one thing still bugs me, though.
Why didn't the controller figure out where the plane was? Just over three minutes before impact, the controller asks the captain for their distance from the airport.
Thai 311, go ahead your DME for Kathmandu.
We are five DME from Kathmandu.
The captain reports that he's five miles away.
The reported distance by the pilots just didn't make any sense to the controller.
It's been five minutes since the Thai captain reported turning back towards Romeo.
If he's flying south, away from the airport, he should be about 25 miles away, not five.
The controller can't see on his screen where this aeroplane's going.
All he can do is have a picture in his mind that the aeroplane is here and it's still following a script.
But guess what? The aeroplane's no longer following that script.
- Confirm, 25 - Five.
05.
The pilot, when the controller asked him about that, very firmly said, "Five.
05.
" And I think that had the effect of shutting down an inexperienced controller.
Roger.
Report over Romeo.
And forcing him to not probe deeper and ask any further questions.
And that's a real shame because I think, in this event, it might have made all the difference in the world.
Are we going north? We will turn back soon.
And then, only many miles north of the airport at some point, does the first officer say, "Hey, my display says I'm north of the airport.
" And he looks over, and he says to the captain, "We're north of the airport.
" But by then it's too late.
- Terrain.
Terrain.
Pull up.
- Turn back.
Turn back! It's false.
It's false.
He's totally locked into being in another place and nothing that the first officer was gonna say was gonna change his perception of where he was.
It's an amazing thing how the mind - how powerful our minds are sometimes when we're convinced we're doing something, even if that something is totally wrong.
The crash of flight 311 underscored the need for more advanced air traffic control technology at Nepal's Tribhuvan Airport.
In an environment like Kathmandu, radar was essential.
And radar was put into Kathmandu so this would not happen again.
The Thai Airways disaster also drove home the crucial importance of teamwork among pilots.
A fundamental rule requiring a division of duties in the cockpit must never be ignored.
It's not easy to realise, "Yeah, I'm so overloaded, I have to start delegating tasks.
I have to stop doing everybody's job.
" He was trying to do everybody's job.
At some point, you have to say, "Enough is enough.
I'll fly the aeroplane.
You handle the communication and tell ATC what I am doing.
Tell them.
"
A lot of tourists fly in just for the scenery.
Thai Airways 311 is bound for Kathmandu.
But it never arrives.
Thai 311, Kathmandu.
Please report your position.
Until the aeroplane is found, it's difficult to figure out what might have happened.
This is where we search.
A high-altitude trek leads investigators to one of the most remote places on Earth.
You couldn't tell that you had an Airbus A310 aircraft there.
You couldn't even tell you had two engines.
How can they ever hope to piece together what happened? Right away, you knew you were really gonna be in a difficult situation.
It is mid-summer in the Himalayas.
Monsoon season, when shifting winds and sudden rains sweep across the jagged mountain landscape.
Just above the awesome peaks flies Thai Airways flight 311.
The pilot flying is Captain Preeda Suttimai.
His first officer is Phunthat Boonyayej.
I will never get tired of seeing these mountains.
It truly is an extraordinary sight, brother.
The flight's 99 passengers are a mix of Nepalese nationals and international tourists all headed to Kathmandu.
Kathmandu is a popular tourist destination.
It's a mountainous airport and a lot of tourists fly in just for that, for the scenery.
The Thai Airways plane is an Airbus A310, a medium-to long-range twinjet.
The A310 overall is a fantastic aeroplane.
It has a range of eight hours and it can carry 20 tonnes at a decent altitude.
The flight from Bangkok to Kathmandu is expected to take roughly 3.
5 hours.
The Nepalese capital lies at more than 4,500ft above sea level.
The approach requires navigating near some of the world's highest mountains.
Kathmandu, Thai 311.
Request descent.
Uh, Kathmandu, Thai 311.
Do you read? The first attempts that the flight crew had with air traffic control, they called three times and got no response at all.
Kathmandu, Thai 311.
Do you read? The acoustics were not very good.
There was a lot of echoing on the frequency.
Maybe it had been caused by the mountains.
Kathmandu, Thai 311.
311, Kathmandu.
Go ahead.
Finally, the Nepalese controller hears the call.
Request descent.
Thai 311, we have negative traffic at or above flight level 150 within our juris Except one in Nepal at 206.
You are cleared for descent.
The controller, he was relatively inexperienced.
He had nine months' experience.
Um, you know, he's not a complete rookie but at the same time, he's got a lot to learn yet.
Ladies and gentlemen, we will soon begin our descent into Kathmandu.
Please stow away your tray tables, raise your seat backs and fasten your seatbelts in preparation for landing.
The flight is now about 30 minutes from its destination.
Lots of clouds.
Let's go through.
Kathmandu's Tribhuvan International Airport is one of the most challenging in the world.
The mountains that tower above the capital force pilots to descend much more steeply than at other airports.
When I look at the approach that the aircraft was going to be flying going into Kathmandu, I'm definitely struck by the steepness of the approach itself and the gradient of the terrain in the area.
Go ahead.
Would you request for runway 02, please? Thai 311, request 02.
Thai 311, confirm requesting 02.
Confirm.
The pilots have requested a straight-in approach from the south to runway two.
It will keep them clear of high mountains north of the airport.
But as they get closer, things change.
Thai 311, Kathmandu.
Go ahead, Thai 311.
Thai 311, for your information, runway 02 not available due to poor visibility and heavy rain toward that side.
You'll have to take runway 20.
Sudden bad weather means the only approach now available is from the north.
It requires circling north of the airport to land on the opposite runway, a manoeuvre the captain does not want to make.
We need runway 02 for the straight-in approach.
You'd be challenged at the notion doing a circling approach in a mountainous environment.
It's one thing to do it over an island, say, in the sea without any obstacles.
It's another thing to do it surrounded by mountains.
I guess we can't make it, brother.
Please check the field to Calcutta.
The captain decides to abandon the landing and divert to an airport in India.
Fuel.
We got enough to get to Bangkok.
And for Calcutta, how much do we need? 18? 14? 42? For passengers, diverting to Calcutta would mean landing more than 400 miles away from their destination.
Thai 311, I've just confirmed that runway 02 is now also available.
Report 25.
Wait a minute.
It seems the unpredictable weather has changed again.
It's good news.
Kathmandu, Thai 311.
Confirm runway 02 available? - Confirmed.
Runway 02 is now available.
- That's lucky.
The straight-in approach from the south is once again clear.
But the plane is now too close to the runway to descend safely.
They were a little bit high for the position that they were at in relation to the airport.
Kathmandu, Thai 311.
We cannot make approach now.
We will need to turn back to Romeo and climb to 18,000ft and start our approach again.
The captain decides to turn around and try again.
It should give him the distance he needs for a safe, controlled descent.
Using the Flight Management System, First Officer Boonyayej looks up a navigational waypoint, called Romeo, to restart their approach.
But there's a problem.
The system won't lock in the flight path to Romeo.
It disappeared.
It's Romeo 27, isn't it? Ro-me-o.
Kathmandu, what is the visibility? Thai 311, standby for tower observation and visibility.
Flying in dense cloud, the pilots' view ahead is extremely limited.
They want to know when they can expect to see the airport.
- Level change.
- Terrain.
Terrain.
Pull up.
A ground proximity warning suddenly begins to sound.
Pull up.
Pull up.
Airspeed low.
- Turn back.
Turn back! - It's false.
It's false.
Terrain.
Pull up.
Don't sink.
- Terrain.
Terrain.
Pull up.
Pull up.
- Oh, my god! Thai 311, please report your position.
Thai 311, Kathmandu.
Please report your position.
In the mountains of Nepal, a search is underway for Thai Airways flight 311.
The Airbus carrying 113 people vanished on approach to Kathmandu.
Nepal has moved quickly to set up a Royal Commission of investigators.
This is the airport.
Flight 311 was coming in from the south, here.
Until the aeroplane is found, it's difficult to figure out what might have happened.
This is where we search.
They search an area covering dozens of square miles to the south of Kathmandu.
And the search, of course, started in the south because it came in from the south.
A methodical search eliminates territory sector by sector.
Where is this thing? The plane is nowhere to be found.
Time is of the essence.
The unpredictable Himalayan weather could bring heavy rains at any moment, making the search all but impossible.
As the mountain search continues, investigators interview air traffic control, hoping for any kind of lead.
We don't have radar here, so I can't help you with the aeroplane's location.
A radar is a line of sight tool.
It doesn't penetrate through mountains or anything like that.
So in a mountainous area like Kathmandu, your radar coverage would be limited to some degree because it would be blocked by the mountains themselves.
I just rely on what the pilots tell me.
In a non-radar environment, they have a mental picture, and that picture is really painted by the words that the pilot reports to them.
They don't have an exact location.
It's almost like working blindfolded.
They were going to restart their approach.
Their last reported position was here, 14 miles to the south of the airport.
Kathmandu, Thai 311.
We cannot make approach now.
We will turn back to Romeo and climb to 18,000ft to start our approach again.
To redo the approach, they would have to turn back towards the south.
There was one thing.
At one point, they mentioned a technical fault.
But a few seconds later they said they were fine.
A mysterious technical fault raises suspicion.
But at this point, there's no way of knowing if it played any role in the plane's disappearance.
They knew the aircraft had some technical problem.
That's what they were told.
You didn't know whether it was a radio fault, a navigation system fault, so we wondered what it was.
It's been almost 48 hours since Thai Airways flight 311 disappeared in the Himalayas.
Investigators have yet to find the aircraft.
But now they're about to get an important break.
Local villagers report that they found aircraft debris north of Kathmandu.
Some people where the aeroplane crashed had heard about it, had heard the crash and they couldn't communicate with anybody as to where it went 'cause they didn't have the means to do so.
Are you sure you don't mean down here, to the south of the city? Investigators can't quite believe it.
The reported crash site is nowhere near the area they've been searching.
I don't think they ever in their wildest imagination thought the aeroplane was north of the airport.
North of Kathmandu, near the border with Tibet, the Himalayan peaks soar to an altitude of 20,000ft.
These northern summits are the reason almost all planes approach Tribhuvan Airport from the south, where the mountains are closer to 8,000ft.
Send out the helicopters.
Tell them to start searching to the north of the airport.
Later that day, 27 miles north of Kathmandu, search crews find the remains of Thai Airways flight 311.
The point of impact is a steep rock face more than 11,000ft up the side of a remote mountain.
It hit, essentially, a vertical rock face and then the whole aircraft just tumbled down into a valley.
There was some small evidence of fire, but mostly just total destruction of the aircraft.
None of the 113 people on-board have survived.
It immediately created mysteries as to what might have happened, why the aeroplane got to a place that it was not expected.
The challenge for investigators is unlike anything they've encountered before.
The terrain is so extreme, helicopters can't land near the impact zone.
The team will have to trek more than 3,000ft up from the base camp to reach the wreckage.
It's a treacherous five-hour hike.
OK.
I gotta stop.
It's a dangerous area.
You had to be very, very careful.
At high altitude, you tend to end up with hypoxia.
It isn't long before the mountains let it be known just how dangerous they can be.
What happened? What's going on? One of the investigators died.
A British investigator for Airbus suffers fatal complications from hypoxemia, a lack of oxygen in the blood due to thin air at high altitude.
It's bad enough that people die in the accident but you don't want other people dying trying to solve the accident or recover things from the accident site.
And so that was a shock.
It's now brutally clear to everyone, on this mission, the stakes could not be higher.
Deep in the Himalayan mountains, Nepal's Accident Investigation Commission makes its way toward the Thai Airways crash site.
The team includes experts from around the world, including Canada's David Rohrer.
You're there to hopefully find something to prevent recurrence, to save somebody else from having that same tragedy in their lives or have a similar outcome.
That's why you're there.
Rohrer is confronted with a scene of total devastation.
The level of destruction was enormous.
You couldn't tell that you had an Airbus A310 aircraft there.
I mean, you couldn't even tell you had two engines.
The first big question they have is, "How did Thai Airways flight 311 end up here?" The Airbus should never have been flying north of the airport.
Searchers soon find the cockpit voice recorder.
But that won't reveal the flight path.
Bring that to base.
Investigators already know the airport has no radar data.
Their best chance of discovering how the plane reached this fatal impact zone is to find the flight data recorder.
Right away, you knew that if you didn't have the FDR then you were really gonna be in a difficult situation in terms of trying to determine cause or probable factors.
- Still no sign of the FDR? - No.
Unfortunately not.
The intensive high-altitude effort has already killed one team member.
Investigators know that their time on the mountain will be limited.
Right over there.
An airport hangar in Kathmandu is the final stop on a long journey for wreckage collected from the mountainside.
The Sherpas would bring down the pieces that we identified down to the landing zone.
Then the Nepalese army in their helicopters would put them in nets and then sling them down to the hangar at the airport.
With still no word on the plane's flight data recorder, investigators review the A310's maintenance records.
In any investigation, you don't just sit and wait for the recorders.
You start doing work right away.
For example, were there any problems with the aircraft before the accident? They already know that the Thai Airways pilots reported an unknown technical fault to air traffic control.
It's a red flag and there's so many different areas that could be called a technical fault.
You know, was it a configuration issue? Was it a power issue? Was it a landing gear issue? It just opens up Pandora's Box of what it can be.
Hey, look at this.
The day before the flight, there was a circuit breaker failure on the plane.
There was a recurring problem with the XP-205 bus.
And that bus was related to navigation equipment, so we were kind of thinking, "Well, perhaps we better look at that in more detail.
" The XP-205 bus carries electrical power to several important systems, including the plane's navigation system.
Maybe the bus failed while they were in flight.
It's possible.
A malfunction in the navigation system could explain the location of the crash.
If that bus failed, it would wipe out the co-pilot's electric instruments, which would show his position and his navigation.
That would be pretty critical.
But in order to prove their theory, they'll have to track down the XP-205 bus amidst piles of burnt and twisted debris.
It's hard to tell what we're even looking at here.
Given the destruction of the aircraft, very difficult to track down those types of technical issues.
As team members comb through the wreckage, the investigation takes an unexpected turn.
Excuse me.
Can I help you? During the investigation, one of the family members were asking for a circuit board, just because it somehow would link them to their loved one.
The unusual request leads to an incredible find.
That's when we actually found the internal mechanism of the recorder we were missing, which was quite amazing.
The FDR should provide crucial data on the plane's speed, direction, and altitude throughout the flight.
You always hope that luck is on your side, that things will happen to your benefit.
And those are the kind of moments you really hope for as an investigator.
It's the breakthrough they've been waiting for, evidence that could reveal how a plane flying south of the airport ended up slamming into mountains to its north.
Ready? OK.
Start it up.
The cockpit voice recorder from Thai Airways flight 311 is finally ready for analysis.
Lots of clouds.
Let's go through.
Investigators hope to hear something that might help explain why the Airbus hit a mountain at over 11,000ft.
Thai 311, Kathmandu.
Go ahead.
Would you request for runway 02, please? Thai, uh, 311, request 02.
- Thai 311, confirm requesting 02? - Confirm.
As they initiate their descent, all seems normal.
I guess we can't make it, brother.
Please check the fuel to Calcutta.
But as the captain considers diverting to Calcutta, the atmosphere in the cockpit seems to change.
Fuel.
We got enough to get back to Bangkok.
And for Calcutta, how much do we need? 18? 14? 42? He's really getting frustrated with his first officer.
I got the impression that thethe answers from the first officer were not what the captain was looking for.
They weren't communicating properly with each other.
Thai 311, I've just confirmed that runway 02 is now also available.
Report 25.
Wait a minute.
Kathmandu, Thai 311.
Confirm runway 02 available? Investigators then notice something else out of the ordinary.
Confirmed.
Runway 02 is now available.
Request surface condition, please.
Wait - wait a minute.
Stop.
The pilot on the radio is not the first officer.
It's the captain.
Why was the captain speaking with the controller? As the pilot flying, the captain should never have been speaking with air traffic control.
It's up to the first officer, as the non-flying pilot, to do the communication.
But it didn't unfold that way.
Normally, division of duties in a cockpit's very important in sharing workload.
But in this case, I noticed that the captain was, in many cases, taking over the radio transmission work.
Speed brake in.
Flap 15.
Speed brake in.
Flap 15 selected.
As they keep listening, they hear the captain's frustration grow.
Damn it! The flaps cannot be extended.
The flaps would not extend to full configuration, which, for the Kathmandu approach, is essential.
It's too late to make a landing.
It's too late.
We can request a return.
Damn it! Kathmandu, Thai 311.
Request to maintain 10,500 and request to go back to Calcutta due to technical.
It's now clear that the technical problem has nothing to do with a circuit breaker.
It's the wing flaps.
They won't extend to 15 degrees.
When they went to 15 and 15, of course they didn't get 15 and 15.
They got the one chime and they had a flap fault.
But just how serious a problem is it? Will it affect the captain's ability to control his plane? Hey.
The flaps have extended.
The recording soon tells them that the flap issue is quickly resolved.
They did cycle the flaps.
They did correct the problem.
Uh, back to normal now.
Can we make a left turn to Romeo? Understand operation normal.
And you'd like to make an approach? Affirm.
Affirm.
The situation appears to be stabilising.
Thai 311, clear Sierra approach.
Report 10 DME leaving 9,500.
But the captain's frustration soon returns.
We can't land at this time.
We have to make a left turn back to Romeo and start our approach again.
Communication with ATC was anything but great.
It was fragmented.
It was unclear.
Thai 311, go ahead your DME distance.
We are nine DME, 10,500ft.
Answer, please.
Answer, please.
Repeated requests to return to Romeo were pretty much unanswered.
Investigators now wonder Kathmandu, Thai 311.
Can we make our left turn back now? .
.
does the Thai Airways crew keep flying towards the mountains because they don't have clearance to change course? We'll climb and turn to the right.
But, despite lacking clearance, the captain takes matters into his own hands and turns his plane right, heading back to the start of the approach.
They're all gone.
They've disappeared! Moments later, there is more uncertainty in the cockpit.
It's Romeo 27, isn't it? Ro-me-o.
Also, the captain seemed to be getting frustrated with the co-pilot's efforts to put things in the navigation system.
This thing failed again.
Why is he having such a hard time inputting the waypoint? Then, investigators hear a surprising question from the first officer.
Are we going north? The co-pilot said something like, "We're going north, huh?" With that inflection like it's a mitigated type question.
The recording presents a troubling contradiction.
Though clearly frustrated with air traffic control and with his co-pilot, it seems the captain managed to turn south away from the mountains.
Yet, minutes later, they hit a wall to the north.
Terrain.
Terrain.
Pull up.
- Turn back.
Turn back! - It's false.
It's false.
- Pull up.
How they ended up slamming into a mountain they were supposed to be flying away from remains a mystery.
- Terrain.
Terrain.
Pull up.
- Oh, my god! In Nepal, investigators have ruled out the possibility that a faulty circuit breaker caused the Thai Airways 311 disaster.
Had the XP-205 bus failed, it would have fired off some warning chimes, which I'm sure they would have talked about, which they didn't.
And so I think that that was probably the main reason we discounted it as a factor.
They wonder if the work records of the two Thai Airways pilots can shed any new light on the investigation.
The captain's record reveals he was a highly trained pilot who had flown to Kathmandu many times.
He was impressive, and I think everybody in the company had identified him as a person who was going to go right to the senior levels of the company.
The co-pilot was older than the captain.
He had a lot of experience, as well.
The first officer has flown into Kathmandu 14 times in the last year.
But as investigators look more deeply into the first officer's record, they make a surprising discovery.
Thai Airways, they categorised you based on whether you were gonna be captain material or whether you were going to be first officer material only.
Interestingly enough, in their assessment, they categorised for the first officer in this case that he would not be captain.
I've always thought that if you tell somebody you're limited, "I will hire you but you're limited," then, well, maybe they'll fulfil that prophecy.
It still doesn't explain how they ended up way up here to the north.
Flight 311 flew 27 miles north of the airport into airspace commercial airliners normally avoid at all cost.
Is that the data from the FDR? Great.
With the FDR data now recovered, investigators have their first chance to analyse the plane's deadly flight path.
'Cause recorders will give you latitude and longitude.
It gives you a nice track as to where the aeroplane went.
First, let's have a look at what they were intending to do.
Can you pass me the published approach? Thai Airways' approach to Kathmandu is from the south.
The crew wanted to land on runway two.
OK.
Roughly here is where they would have decided on the missed approach.
This is where they were supposed to go.
Let's see what they actually did.
The data shows flight 311 proceeding north towards Kathmandu.
Everything seems to be in order.
And right here, they're looping around to restart their approach, right? Alright.
They were supposed to level out.
They just kept turning.
Instead of straightening out and heading to Romeo, flight 311 does a complete 360-degree turn.
When I saw it, I was you know, I was amazed because I couldn't understand why they would want to do that.
It just doesn't make any sense.
Why the Airbus flew in a complete circle back on a collision course with mountains north of the airport is a mystery investigators must solve in order to understand why 113 people died aboard the Thai Airways flight.
- Ready? - Ready.
Fire it up.
In search of answers, they turn to a flight simulator.
In terms of simulator testing, the one thing that it allows the investigators to do is to replicate what happened and understand what the crew would see or any other problems that they would face.
The captain just took over communications with the controller.
Yeah, OK.
Kathmandu, Thai 311.
Confirm runway 02 available? At this point, the captain is flying the aircraft, monitoring the instruments, and speaking to the controller, all on one of the steepest, most difficult descents in aviation.
Speed brake in.
Flap 15.
Speed brake in.
Flap 15 selected.
Damn it! The flaps cannot be extended.
The flap issue is temporary.
But time spent resolving it forces a delay.
They can no longer make the straight-in landing.
Let's see.
OK.
No.
We are too high and too close for the approach.
The only choice is to circle back and do another approach.
The controller hasn't given clearance.
He keeps asking for the aircraft's altitude and distance from the airport.
Hang on.
We are getting very close to the mountains, right? We need to make a turn soon.
The autopilot takes the plane to a selected heading in the shortest way possible.
In this case, that would mean turning to the left.
The controller said there's traffic to the left.
OK, there is a lot going on here right now.
And he still hasn't cleared you to go back to Romeo.
Needing to turn before he reaches the mountains north of Kathmandu and with traffic on his left, the captain decides to override the autopilot.
We'll climb and turn to the right.
He can turn right by turning the heading knob incrementally in the same direction.
The aeroplane was turned most likely by changing the heading bug.
In other words, the captain has that option.
He just turns a heading selector and the aeroplane will turn.
- Watch your turn.
You're centre level off.
- Oh.
Yeah.
Right.
The climb, turn, descend with an autopilot, that's tough to do.
And he was doing all of that in the turn.
- OK.
You're starting to fly south now and should straighten out.
- Yes.
But he gets yet another call.
The controller tells him to lower the altitude to 11,500ft due to traffic in the area.
OK.
Thai 311, descend to flight level 11,500.
It started to really become apparent that, you know what? With all the distractions, with all the workload that the captain had that eventually, you know, the monkey climbed on his back and he took on the whole load of the operation.
Investigators are close to a breakthrough.
And this is the moment they should have stopped adjusting the heading.
The simulation gives them a sense of the mounting pressure in the Thai Airways cockpit.
An extremely busy captain flying a challenging approach attempts an improvised right turn.
He's trying to do too many things at once.
He's asking to go to a point, he's trying to fly the aeroplane on the autopilot and he's starting to lose the 3D picture that he has in his head where he is.
Without realising it, he turns the heading knob too far.
He turned it one too many times and did a full circle.
Each time he has to reach up and change his heading, he has to take his eyes off the ball.
What's the one thing that we never do? Is take our eyes off the ball.
Well, each time he reaches up to select a different button, he takes his eye off of the screen.
The captain took on too much himself where the point he was distracted from his primary task, which is to navigate the aeroplane.
Investigators finally understand how the plane ended up heading in the wrong direction.
But they still wonder why the crew didn't notice the mistake in time.
After he did the turn, they kept flying north for more than five minutes.
As the pilots head toward disaster, they struggle to input the Romeo waypoint.
Their frustration with the flight computer should be a warning sign.
Romeo is now behind them.
How could they not notice? Why the Thai Airways crew failed to notice that they had turned their plane 360 degrees back towards the towering Himalayan mountains is one of the last mysteries investigators want to solve.
The team tried to understand as to why the crew continued to the north.
What cues could they have got and why did they ignore those cues? Take a look at this.
There are no cardinal points on the compass.
A close look at the cockpit compass reveals a possible explanation.
The instrument lacks the usual direction markers, N-S-E-W, for North, South, East and West.
It had just numbers.
I think if there had been a big 'N' on top of the compass the whole time, it might have made a difference.
When you're fully confident about where you're going, at what altitude, in what direction, when you think you have the mental picture, but yet you don't actually have the mental picture, you're situationally unaware of where you are.
You know, one thing still bugs me, though.
Why didn't the controller figure out where the plane was? Just over three minutes before impact, the controller asks the captain for their distance from the airport.
Thai 311, go ahead your DME for Kathmandu.
We are five DME from Kathmandu.
The captain reports that he's five miles away.
The reported distance by the pilots just didn't make any sense to the controller.
It's been five minutes since the Thai captain reported turning back towards Romeo.
If he's flying south, away from the airport, he should be about 25 miles away, not five.
The controller can't see on his screen where this aeroplane's going.
All he can do is have a picture in his mind that the aeroplane is here and it's still following a script.
But guess what? The aeroplane's no longer following that script.
- Confirm, 25 - Five.
05.
The pilot, when the controller asked him about that, very firmly said, "Five.
05.
" And I think that had the effect of shutting down an inexperienced controller.
Roger.
Report over Romeo.
And forcing him to not probe deeper and ask any further questions.
And that's a real shame because I think, in this event, it might have made all the difference in the world.
Are we going north? We will turn back soon.
And then, only many miles north of the airport at some point, does the first officer say, "Hey, my display says I'm north of the airport.
" And he looks over, and he says to the captain, "We're north of the airport.
" But by then it's too late.
- Terrain.
Terrain.
Pull up.
- Turn back.
Turn back! It's false.
It's false.
He's totally locked into being in another place and nothing that the first officer was gonna say was gonna change his perception of where he was.
It's an amazing thing how the mind - how powerful our minds are sometimes when we're convinced we're doing something, even if that something is totally wrong.
The crash of flight 311 underscored the need for more advanced air traffic control technology at Nepal's Tribhuvan Airport.
In an environment like Kathmandu, radar was essential.
And radar was put into Kathmandu so this would not happen again.
The Thai Airways disaster also drove home the crucial importance of teamwork among pilots.
A fundamental rule requiring a division of duties in the cockpit must never be ignored.
It's not easy to realise, "Yeah, I'm so overloaded, I have to start delegating tasks.
I have to stop doing everybody's job.
" He was trying to do everybody's job.
At some point, you have to say, "Enough is enough.
I'll fly the aeroplane.
You handle the communication and tell ATC what I am doing.
Tell them.
"