Original subtitles

(narrator): Above the English Channel,

a Piper Malibu suddenly disappears from radar.

- Where did you go?

November 264 Delta Bravo, do you read?

(narrator): Search teams find no trace of the plane

or its high-profile passenger.

(news): Tonight, Emiliano Sala is missing.

- This began as a small, general-aviation accident,

and it very quickly became of worldwide interest.

(narrator): As recovery crews search the sea,

the pilot's background is investigated.

- He didn't have a full instrument rating.

- That rang alarm bells for me.

(narrator): But when they locate the plane, theories change.

- Look at the bending of the splice joint.

- The plane broke up before it hit the water.

- So now what we had to establish was:

Why did the aircraft break up in flight?

- Mayday, Mayday!

- It's going up!

(indistinct radio chatter)

(narrator): A chartered Piper Malibu is moments from takeoff.

Pilot David Ibbotson prepares the plane for departure

from Nantes Airport in France.

- November 264 Delta Bravo ready for takeoff.

(narrator): Ibbotson has a VIP on board.

Argentinian footballer Emiliano Sala.

(speaking Spanish)

(narrator): The star striker is leaving Nantes for good.

He's moving up to the Premier League to play for Cardiff City Football Club

for 17-million euros.

- This was the move up

to one of the world's richest leagues seen around the globe.

It would've propelled him to absolute superstardom.

(narrator): It's a two-hour flight from Nantes to Cardiff, Wales,

crossing over the English Channel.

This is Emiliano Sala's second flight with Ibbotson.

Two days earlier, he flew back from Cardiff,

where he signed his new contract.

- Emiliano wanted to go back to Nantes

to be able to say proper goodbyes to his teammates, his friends.

He'd left in the middle of the night,

and hadn't really told them that he would be signing for Cardiff City.

- November 264 Delta Bravo.

Requesting clearance to climb to flight level 55.

- November 264 Delta Bravo,

you are cleared to flight level 55.

(narrator): The Piper Malibu can carry five passengers,

but tonight, Emiliano Sala is travelling alone.

- Are you warm enough?

- Sorry? - Are you warm?

- Tengo frío.

- It's a comfortable aircraft.

It will cruise at a reasonable speed.

It's quite large, it's quite fast for a light aircraft.

(narrator): The plane climbs towards a cruising altitude of 5,500 feet.

- It would've been relatively easy to conduct this flight back from Nantes to Cardiff

in clear weather.

(narrator): As they approach the Channel Islands,

the weather changes.

Rain clouds loom on the horizon.

- The pilot's visibility would've deteriorated

as he approached the cloud conditions over the Channel Islands.

- November 264 Delta Bravo.

(narrator): With conditions worsening,

David Ibbotson contacts Air Traffic Control.

(pilot): Requesting clearance to descend to maintain VMC.

- November 264 Delta Bravo,

you are cleared to flight level 50.

Just advise if you need further descent.

- November 264 Delta Bravo. Thank you, sir.

(narrator): Ibbotson takes the Piper lower to avoid the bad weather.

- The cloud layers would've obscured what little light was available

from the islands of Jersey and Guernsey.

And the forward visibility would've been such

that the horizon would've been indistinct and difficult to make out.

- Are you good back there?

Um, November 264 Delta Bravo.

Requesting further descent to maintain VMC.

(narrator): But 10 minutes later,

Ibbotson still hasn't been able to clear the clouds.

- Cleared to descend at your discretion.

- Uh, Roger.

(narrator): The Piper Malibu is one hour from Cardiff.

But as the controller follows the plane's progress,

it disappears from radar.

- November 264 Delta Bravo, how are you making out there?

Where did you go?

November 264 Delta Bravo,

do you read?

Uh, yes, I've got a Piper Malibu missing from radar

near the Channel Islands,

uh, north of Guernsey.

Registration number is...

November 264 Delta Bravo.

(narrator): News of the missing Piper spreads quickly.

- Word starts to emerge that a Piper Malibu has gone down in the Channel.

Um, and fairly soon afterwards, sports journalists start saying:

Wasn't Emiliano Sala due to travel to Cardiff the same night?

(narrator): An air-and-sea search gets underway

for a plane that disappeared over the English Channel.

Search-and-rescue teams launch an expansive search

of the Channel overnight and into the next morning.

But the plane remains lost.

- Good morning. - Hello.

(narrator): Meanwhile, a team from Britain's AAIB,

or Air Accidents Investigation Branch,

is assigned to the case.

- Radar data's come in.

Check your inbox.

- Great. I'll bring it up.

(narrator): They wonder exactly where the Piper went down in the English Channel.

- We contacted ATC and we asked for their radar information. We used that radar information,

we were able to put it together to provide a track of the aircraft.

- Looks like... the last-known radar hit is...

...right here.

So it should be...

...close to here.

(narrator): Investigators begin to zero in on a search area

north-northwest of the island of Guernsey.

- These are... deep waters.

It's too deep for divers.

- And the strong currents.

I'll get the coordinates to the marine team.

- When we first started looking at the radar information,

and trying to turn that into a location in the sea,

our marine advisors looked at tides.

That gave us a seabed location which we had reasonably good confidence in.

(narrator): While search-and-rescue teams begin more targeted efforts,

the world gets the news everyone feared.

- Emiliano Sala was on board.

(narrator): French police confirm to news outlets

that Emiliano Sala was on the missing Piper Malibu.

- Given the temperature of the water and the weather conditions,

it was very rough last night.

Their chances of survival are very, very slim.

(news): In Nantes, more affection for a much-loved player.

(reporter translating): We ask you to stand with us,

to be united and to respect the family.

They refuse to grieve and continue to believe.

- Th-that's great.

Everything you can find.

Okay. Thank you.

I've got a team working on securing any mobile messages sent by the pilot or Sala.

- Good idea.

Okay.

(narrator): As the search continues,

investigators look for any clues as to why the Piper Malibu went missing.

- You see, he deviates a bit to the right as he approaches Guernsey,

but he's pretty much right back on course not long after.

- And the altitude holds steady at 5,000 feet during that time.

Nothing too unusual.

- Right. But zoom in towards the end of the flight. - Right.

- Check out those turns.

(narrator): They discover the plane made a wide turn to the right

three minutes before it disappeared...

...followed by a hard left.

- Look at that final right turn.

- It's almost...

180 degrees.

(narrator): The Piper then made a sharp right turn

seconds before vanishing from radar.

- So we could see from the radar track that things began to go very strangely.

There was a lot of turning, both left and right.

And it culminated in a very sharp turn to the right.

(narrator): What would cause such erratic deviations

ending in a steep dive?

- The behaviour that we were seeing,

which was an increasing turn rate

and an increasing rate of descent,

looked like the beginning of a manoeuvre that we call a spiral dive.

- And look at the...

altitude fluctuations.

- Up and down, and then a very rapid descent.

- For the final few moments of that flight...

...this is a plane that is ascending,

that is descending, that is meandering, and ultimately,

this plane is going to end up in the sea.

(narrator): Did the plane suffer a loss of control

before plunging into the English Channel?

- But even if we do find the plane,

it's still going to prove to be quite challenging.

- There's no CVR or FDR on the Malibu.

- Not having a flight-data recorder or a cockpit voice recorder

makes it incredibly difficult to establish what happened

in the last few minutes of that flight.

(narrator): After three days, the search for survivors is called off.

The world mourns the loss of an up-and-coming footballer.

Messages of condolence flood in from football clubs and players

who pay tribute to Emiliano Sala.

While families grieve,

recovery teams deploy ships equipped with side-scan sonar,

hunting for the Piper Malibu at the bottom of the English Channel.

But finding the wreckage 22 miles off the coast of Guernsey is slow going.

- There were high tidal flows,

and it was further complicated

by the winter storms that were coming through.

(narrator): Pressure is on the AAIB to find the wreckage.

- This starts as a small story about a plane going missing,

and then suddenly there is somebody famous on board,

and the whole world wants to find out exactly what's happened here.

- So, uh, this sector looks clear.

Okay... let's move on.

(narrator): Thirteen days into the investigation,

search teams continue to scour the bottom of the English Channel,

looking for the missing Piper Malibu, its pilot,

and its sole passenger, footballer Emiliano Sala.

- We knew it was gonna be very difficult.

And at that stage, we didn't expect to actually find it.

(playback of Sala's phone message)

- Uh... hey, I've got something. You won't believe it.

- What is it?

- A message Sala left before takeoff.

(speaking Spanish)

- So in the few moments before the plane took off,

Emiliano Sala sent a voice note to his friends

back home in Argentina.

(narrator): Investigators discover that Emiliano Sala

raised concerns prior to takeoff.

- Was there, uh, some kind of mechanical problem with the plane?

- That's a good point.

I'll check the maintenance history.

- We looked to see whether the aircraft was maintained properly,

and whether there's any hints that there could've been some form of mechanical failure.

- The last full check was in November.

- So... two months before the flight.

- Well, it's only flown 11 hours since then.

As far as general maintenance is concerned,

the plane checks out.

- When we looked at those records,

they were all in order and it wasn't suggesting

there should've been any sort of mechanical failure.

- Check that. That looks promising.

(narrator): Fifteen days into the investigation,

search teams make a critical discovery.

- I bet that's our plane.

- Finding the aircraft was a big breakthrough for the investigation.

- Thanks. No, that's great.

Uh... thanks for the update.

Not only did they locate the plane,

but they...

...found one of the bodies.

(narrator): Emiliano Sala's body is found inside the plane.

His remains are sent to a pathologist for analysis.

The pilot's body isn't found.

AAIB investigators turn their attention

to video footage taken of the debris

at the bottom of the English Channel.

- Pause it... on the forward section of the fuselage.

(narrator): Was the plane out of control when it hit the water?

- Look at the damage to the roof.

- One of the most interesting things about the wreckage

was that all the compression damage was on the top surfaces,

not on the lower surfaces.

So what this showed us was that the aircraft had hit the sea upside down.

That is, in an inverted attitude.

- Let's check the tail for damage, as well.

- I didn't see it in the earlier footage.

- Ah, it's missing. - Hmm.

- They didn't find it.

- The outer section of the left wing is gone too. - Actually, for both wings.

- We did try and find them. The Coast Guard was looking for them,

and we were hoping that they might be washed up somewhere,

but they never appeared.

- It's hard to know when... these pieces separated.

(narrator): Did the tail and outer wings break off before or on impact?

- Look at the bending of the splice joint.

- Check out the direction of the bending.

(narrator): A close examination of the left wing provides a vital clue.

- We could see that the left wing failed

as a result of the outer section being bent downwards.

- That can only mean one thing.

- The plane broke up before it hit the water.

- The finding that the left wing failed...

...bending downwards, was very significant.

Because if the tail failed in flight,

the aircraft nose would pitch down, causing the wing to fail,

bending downwards.

(narrator): Investigators conclude that the in-flight breakup began

when the tail broke off,

causing the wings to bend downwards,

ripping off their outer portion before impact.

- So now, what we had to establish was:

Why did the aircraft break up in flight?

- Let's try modelling the radar data.

- We used a software simulation...

where you enter the radar information that we had,

and it uses aircraft laws of motion

to give us information about the airspeed, the angle of bank,

and the G-force on the aircraft.

- Okay, let's take a look.

(narrator): Using the plane's altitude and coordinates over time,

investigators are able to plot the plane's manoeuvres.

- Okay, so this is the plane's last turn,

starting at...

20:16.

(narrator): They examine the most mystifying manoeuvre,

the final dive towards the water.

- The plane starts at 190 knots,

and continues speeding up to almost 280 knots.

- That's well beyond the... structural limits of the plane.

(narrator): The team discovers that the excessive airspeed led

to the aircraft's mid-flight breakup.

- Aircraft have maximum speeds, beyond which you must not take them.

Because if you take them above those speeds,

then you risk structural damage to the aircraft.

And in this case, we saw the aircraft go way above those speeds.

- Why was the pilot flying so fast?

- Why does he make all those turns?

- My immediate thoughts on seeing that turn was it was extreme,

and there was clearly something very wrong going on in the aircraft at the time.

(narrator): Investigators receive Emils toxicology r.

Could the results shed any light on the mysterious crash of the Piper Malibu?

- When we receive the results of the postmortem,

we rely on the pathologist to indicate to us

if there's anything that's abnormal.

- There's nothing unusual in Sala's toxicology.

- Alright, then. Let's bring up the weather report. - Right.

(narrator): The team turns to the weather data towards the end of the flight

in hopes of explaining why the Piper Malibu lost control.

- Well, that doesn't look good.

- Rain.

A lot of it. - Hmm.

It looks like he's turning as he's...

approaching those cells.

- Maybe he's trying to fly around the clouds.

- When you're flying at night, with very little light,

there are lots of ways in which your body can become confused about where you are in space.

Are you climbing or descending? Are you turning left or right?

And that can quite easily lead to a loss of control.

- So tell me about the flight.

(narrator): Investigators speak with the air-traffic controller.

- Uh, everything seemed... totally normal,

then he just... disappeared off the radar.

- And... before you lost him,

uh, did you hear anything... unusual?

- Not really.

He did ask to descend twice...

to stay in visual conditions.

- November 264 Delta Bravo.

Requesting further descent to maintain VMC.

- Cleared to descend at your discretion. - Uh, Roger.

(narrator): Not only was the pilot trying to fly around the clouds,

he was trying to descend below them for better visibility.

- You know, here's what I don't get.

The pilot has instruments to help him fly through poor visibility.

- Well, he's clearly not using them.

- Perhaps he doesn't know how to use them.

- What do we have on this pilot?

Let's... figure out exactly who's flying this plane.

- We had a pilot that had manoeuvred, we think, to avoid weather,

but appears to have lost control.

So that raised the question about: Why did that happen?

- Thank you.

And here it is.

His current private licence. It has all his ratings.

(narrator): Did the pilot have the required experience to fly the plane in bad weather?

- The family were able to share his laptop with us,

and on there was a photograph he'd taken of his licence.

- He didn't have a full instrument rating.

- He also had what's called an Instrument Rating Restricted.

So that's a limited instrument rating

that allowed him to operate in some conditions

in instrument flight rules.

- Plus... he hasn't flown using his instruments

in almost...

two years.

- He hadn't had any recent practice

in flying the aircraft in cloud or on instruments,

and instrument flying is a perishable skill; you forget it quite quickly.

- Oh, that's not the worst part.

The flight plan he filed for had a nighttime departure. He doesn't have a night rating.

- From our evidence of Mr. Ibbotson's recent flying, it was all done in daytime,

in good weather.

(narrator): Investigators conclude that Ibbotson's licencing was inadequate

for a night flight in instrument conditions.

- Oh, there's something more.

- Every turn we took seemed to open a lot more cans of worms that we needed to investigate.

- Check this out.

- It's a summary of Ibbotson's projected expenses.

- Exactly.

And look here.

- Pilot fee?

- That rang alarm bells for me, because this guy's...

only a private pilot's licence holder; he's not entitled to be paid.

- November 264 Delta Bravo ready for takeoff.

- He didn't have a night rating,

and he didn't have a commercial pilot's licence.

Essentially means this pilot should not have been operating this flight.

- So...

...who paid him?

(narrator): Who contracted an inadequately licenced pilot to fly Emiliano Sala to Cardiff?

- Getting to the bottom of who organized this flight was very difficult.

There was no... contract,

there were no receipts, there was no agreements.

This was all done by word of mouth or telephone.

- It's a wall of silence.

(narrator): They get very little information about the flight

from the owner of the Piper Malibu.

- Oh, I've got a tip. - Hmm?

- Someone wants to talk.

Discreetly.

- Well, let's... talk to them. Hmm?

(narrator): Is this the break investigators need?

- David Henderson arranged the flight.

He works for the owner.

(narrator): Investigators meet with a witness who has more information

about Emiliano Sala's flight over the English Channel.

- The witness that came forward wanted to give us information,

but didn't want to be identified.

(narrator): The informant provides insight

into the accident aircraft and its operator.

- So Henderson hired the pilot? - That's right. - Okay.

(phone ringing) - Ibbotson here.

(narrator): They learn that David Henderson keeps a roster of pilots.

- Mr. Henderson, how are you?

(narrator): David Ibbotson was one of them.

- Henderson asked Ibbotson if could he fly a passenger

from Cardiff to Nantes and back again.

- I think I can do that.

- Mr. Ibbotson would've known that he had no night rating.

And he would've known, as a private pilot's licence holder,

that he was not entitled to be paid for the flight.

- What is the departure time from Nantes?

(narrator): Investigators uncover more about the flight's schedule.

- So the original plan for the flight was for Mr. Sala to fly back on Monday morning.

- The circumstances changed.

The flight to Cardiff kept getting delayed.

- Mr. Henderson. Ibbotson again.

- There were numerous changes to the departure time over the weekend...

- Uh, sorry to say we have a further delay.

- ...that was pushed back at the request of the passenger.

- So he was supposed to be flying in conditions with good visibility,

during the day... but that changed.

- And he doesn't have his night rating.

- Have you seen anything like this before? - This is a first.

- What we started to see a picture of...

was an operation in the shadows.

It was unlicensed,

had no approval to do commercial work.

They were using an unqualified pilot.

- We have to figure this out.

Work your contacts.

Let's... see what we can find.

(narrator): Are chartered flights with unlicensed pilots common?

- It was very challenging to assess... the extent that this was going on.

There's no records kept,

there's no flight plans made.

And witnesses are understandably reluctant to talk about it.

(narrator): Investigators learn about flights that aren't properly licenced -

called "grey charters."

They offer a discounted price, which comes with increased risk.

- The problem with grey charters is that the aircraft being used to operate them

are often not maintained to the same safety standard as commercial airliners.

- Witnesses came to us to talk about the prevalence of grey charters.

We could see a pattern emerging of how common this was in aviation in the UK.

(narrator): Four months after the crash of the Piper Malibu,

investigators are close to releasing a final report...

...when the case takes an unexpected turn.

- Oh, it's from the pathologist.

He did some additional testing on Sala's bloodwork.

Oh, he just sent me the analysis.

- Sala had... carbon monoxide in his system.

- The pathologist had ordered toxicology tests,

but that had not included carbon monoxide.

And when he realized he'd missed that,

he put in a request for just the carbon monoxide to be tested.

- This had really been a story about a pilot flying

outside of his competency,

in weather that he'd neither practised nor prepared for.

And it was all down to him.

The onus was being put on him.

And then suddenly we get this finding of carbon monoxide,

and that really made everyone... think again.

- Sala's carbon-monoxide levels were at 58%.

(narrator): Toxicology testing reveals that footballer Emiliano Sala

had high levels of carbon monoxide in his system.

- I was shocked by the level of carbon monoxide that was in his blood.

- What would that have done to him?

- Carbon monoxide over 50%:

Unconsciousness and...

...eventual death.

- Sala was out. - Hmm.

- He wouldn't have been conscious when the plane crashed.

- Are you warm? - Tengo frío.

(narrator): Carbon monoxide is a colourless, odourless, flavourless gas.

- You don't know it's there. You don't know you're breathing it in.

And yet it's so dangerous and it can kill you quickly.

(narrator): Even low levels of carbon monoxide are dangerous.

- Are you good back there? - The first thing that happens is you get a headache.

You might feel confused, drowsy.

You start not being able to do tasks that you would normally find easy.

(narrator): The question is: Did Sala's carbon-monoxide poisoning

come from the plane or somewhere else?

- Right.

(narrator): Did Emiliano Sala show signs of carbon-monoxide poisoning

prior to his flight on the Piper Malibu?

The AAIB seeks help from French investigators.

- We had our colleagues in France...

talk to people at Nantes Airport...

to see what the behaviour of the pilot and the passenger had been

as they were going through the airport on the way to the airplane.

- Well, how did the passenger seem?

(narrator): Officials at Nantes Airport scrutinize security footage of Sala

to see if there was anything abnormal about his actions.

(AAIB investigator): What about the pilot?

Okay. No, that...

That's great. Thanks.

Negative.

Sala... seemed fine.

The pilot was alert, he wasn't swaying.

- That means the carbon-monoxide poisoning was from the plane.

(narrator): David Ibbotson's body was never recovered

from the English Channel.

His carbon-monoxide levels couldn't be determined.

- You know...

maybe the modelling data...

will shed some light.

(narrator): Investigators return to the flight-path data for further insight.

Was the pilot affected by the poisonous gas?

- Straight... level.

Looks like... it's on autopilot.

- Hmm. - It's hard to know if he was conscious or not.

- Next, the plane turns right... and then turns left.

- Look at these bank angles.

Thirty-six degrees to the right,

and then 56 degrees to the left.

Those angles are...

well beyond the limits... of the autopilot.

(narrator): Investigators discover that the pilot was conscious enough

to be turning the plane in the final stage of flight.

But was he conscious during the last minute of flight?

- Then here, the plane is in its dive,

with its right wing pointed right down, straight at the water.

- It's hard to believe he was fully conscious for that. - Yes.

- Hello. Check this out.

Before the plane broke up,

the wings almost level out.

- Either the pilot could've applied pressure on the control column -

for example, by slumping over it -

and that could've caused the wings to roll level.

- Check out the pitch.

There's a slight increase.

(narrator): In the final moments,

the pitch of the Piper Malibu starts to rise.

It's evidence that the pilot must have been partly conscious.

- But for the aircraft to start to pitch up,

the pilot would have to be conscious enough

to pull the control column rearward.

- His carbon-monoxide levels had to be lower than the passenger's.

- Right. Well, he may have been conscious,

but he still could've been badly impaired.

- He may have been slipping in and out of consciousness,

and may have made a token effort to recover the aircraft from the steep descending turn.

- Without Mr. Ibbotson's body, it's impossible to know...

...how much he was affected by carbon monoxide.

But we know they were sitting in the same confined cabin.

- Okay.

We need everything there is on the Piper Malibu exhaust and ventilation system.

- The carbon monoxide is carried by the exhaust gasses,

which are generated by the engine.

We needed to understand: How did those exhaust gasses get into the cabin?

- Are you warm?

- Tengo frío.

- I've pulled the schematics. - Great.

(narrator): Investigators study the exhaust and ventilation systems

of the Piper Malibu

to determine how carbon monoxide could have entered the cabin.

- Maybe...

there was an exhaust leak

that seeped...

through the firewall...

...and the pressure bulkhead.

- Maybe, but...

only if there was a crack or a... a leak.

(narrator): Piston engines produce high concentrations of carbon monoxide

that can potentially enter the cabin as a result of cracks, holes,

or poorly fitted components in the exhaust system.

- The team did a lot of work on...

...potential sources for the carbon monoxide in the cabin,

and we talked to the manufacturer and to the engine manufacturer.

(narrator): Seals in the firewall and the forward pressure bulkhead

form an airtight barrier preventing engine fumes from entering the cabin.

- Here's the thing.

Maintenance inspected the firewall and the pressure bulkhead

two months ago.

There's no signs of cracking or broken seals.

- During the last maintenance inspections,

the engineers found nothing wrong with the firewall or the pressure bulkhead.

(narrator): Investigators consider a different possibility.

- What if...

there was a puncture...

...in the exhaust piping?

(narrator): Did a breach in the exhaust system

allow poisonous fumes to mix with the fresh air

used to ventilate the cabin?

As fresh air enters the aircraft,

it's warmed by the engine's exhaust pipe

inside a chamber called the heater muff

before circulating into the cabin.

- What if the puncture happened

after the last inspection?

- Let's check the logbooks.

(narrator): They look for any history of an issue near the tailpipe.

- No. Nothing here.

- What about... on the flight...

over to Nantes?

- That's a good point. Maybe something happened there.

- On the way to Nantes, Mr. Ibbotson did encounter a number of problems

with the aircraft that he reported to various parties.

- Thank you.

It sounds like there were some issues on the flight on the way over from Cardiff.

- Like what?

- Well, there was a small oil leak.

And... during the landing, his brakes gave him problems.

Both were checked and... they weren't a safety concern.

- Okay. - This one is more troublesome.

He reported a bang mid-flight.

And the cabin filled with mist.

(narrator): Two days before the fatal flight,

Ibbotson piloted Emiliano Sala from Cardiff to Nantes

to pick up his belongings and say his goodbyes.

(bang)

- What the...?

- It's okay?

- Uh... yeah, yeah. It's... it's okay.

- The plane is mid-Channel.

(Thomas): He talks about a bang,

something that really kind of grabbed his attention.

He checks to see if everything is working as it should do.

The plane keeps flying. But in the back of his mind is: What on earth was that?

- Maybe the turbocharger failed on the way over to Nantes,

and punctured the tailpipe.

(narrator): Did a turbine inside an engine turbocharger break,

puncturing the exhaust pipe,

allowing poisonous gas into the cabin?

- If you do have damage to the tailpipe...

then there is a possibility

that exhaust fumes and the carbon monoxide can flow

into the fresh air and into the cabin.

- Interesting theory, but I...

I've got an idea.

(narrator): Investigators check with the National Transportation Safety Board,

in the United States, where the Piper Malibu is manufactured.

- Oh... really?

No, that's... that's fine. Thanks. Thanks so much.

- We became aware that the NTSB were investigating events where a turbine wheel

in a turbocharger came away.

- Okay. It's happened twice before.

(narrator): Coul ee component on the Piper Malibu

have come apart and punctured the exhaust system,

releasing toxic fumes into the cabin?

- We don't know the cause of the bang on the outbound flight from Cardiff to Nantes,

and we may never know.

(narrator): Investigators learn of two similar cases in the United States.

- In both cases...

...the pieces of the turbocharger only left score marks.

The tailpipes were never punctured.

- We considered it unlikely that a failure of the turbocharger

would've allowed carbon monoxide to enter the cabin.

- Well, what if the tailpipe cracked on its own?

- Well, it is a pretty harsh environment inside the engine. - Exactly.

Heat, vibration. Prime conditions for a crack to develop.

- If you look at all the separate components in there

for signs of failure, or wear, et cetera,

and where necessary, you'll replace components.

- A visual inspection of the tailpipe is part of their maintenance check.

- Uh, and the plane only flew for 11 hours after its... last inspection.

- Maintenance found nothing wrong with the tailpipe or the exhaust system.

- Not a lot of time for a crack to develop. Is it even possible?

- Huh.

(narrator): They study other accidents for instances of cracked tailpipes.

- Oh, look at this one.

(narrator): Investigators find a disturbing case

of carbon monoxide leaking into the cabin of a small plane.

- A crack in the exhaust formed just six flying hours after a maintenance inspection.

- Even if the mechanics had carried out an inspection,

a crack may have developed sufficient to cause carbon monoxide to leak

into the cabin during those 11 flying hours.

(narrator): They conclude that a sudden crack in the tailpipe

was the likeliest reason carbon monoxide leaked into the cabin.

- The maintenance inspection they did on the Piper... was a visual one.

(narrator): Is a visual inspection the safest way

to identify early signs of cracking in a tailpipe?

- According to the engine manufacturer,

the best way to test for small cracks is a pressure test.

(narrator): To inspect the tailpipe,

a soapy solution is applied to the exterior.

If bubbles form, that means there's a crack.

- But is it a requirement for a private operator?

- The FAA doesn't mandate it. - Well...

what about a commercial one?

- It looks like a pressure test is required

for... commercial operators.

- Had the aircraft been maintained under regulations for commercial use,

which was the way it was actually being used,

it would've meant that during the maintenance,

there was definitely a documented pressure test

of the exhaust system.

- If this had been a very small crack

that was missed by a visual inspection...

...maintenance may have caught it.

(narrator): The AAIB releases its report on the crash.

It concludes the pilot lost control

while turning the aircraft to regain visibility,

which resulted in an in-flight breakup.

Among the causes,

it points to a leak of carbon monoxide into the cabin.

It also cites a lack of safety standards

from the operator of the Piper Malibu as a contributing factor.

As a result of the AAIB's investigation,

the Civil Aviation Authority launches a campaign to raise awareness

of the dangers of grey charters.

David Henderson is ultimately jailed for his role in the accident.

- This was a real moment for the industry to take a good, hard look at itself,

to use that as an opportunity to try to change things,

to try to make sure that something like this didn't happen again.

- There were a lot of sporting organizations for which...

grey charter might have been part of the culture of those organizations.

And I think this accident made them sit up and take notice about the risks

that their members were taking.

(narrator): It was a risk that ultimately took the life of Emiliano Sala,

a rising football star,

on the day he said goodbye to his teammates in Nantes

and flew towards his new future.

Subtitling: difuze