Original subtitles

NARRATOR: Staring down a thunderstorm above the North Sea...

FIRST OFFICER: Take a look at that.

CAPTAIN (off screen): Oh, I don't like it.

NARRATOR: A modern turboprop is struck by more than a million volts.

CAPTAIN: Oh!

DAVID MILLER: After the lightning strike,

you're obviously looking to see, have we been damaged?

CAPTAIN: Damn it!

The plane's not responding. Help me pull.

MILLER: You can fly an aircraft without a compass.

You can fly an aircraft without a radio.

FIRST OFFICER: Mayday, mayday, we've been struck by lightning

and are having control difficulties.

MILLER: But you can't fly an aircraft without functioning controls.

NARRATOR: But investigators can't figure out how lightning

could have caused the plane to behave the way it did.

SECOND INVESTIGATOR: Look at that.

I mean, the elevators are trying to get the nose

to pitch down instead of up.

JULIAN FIRTH: We'd not come across an aircraft

where there would be this difference between the pilot input

and what the aircraft was actually doing.

- CAPTAIN: Oh no! - FIRST OFFICER: We're dropping!

SECOND INVESTIGATOR: They were so distracted by that,

they failed to see what was really going on.

♪ ♪

MAN (on radio): Mayday, mayday!

(radio chatter)

NARRATOR: It's 6:45 pm.

Loganair flight 67-80 cruises

over the North Sea near Scotland.

CAPTAIN: Let's get lower.

Request flight level 1-1-0, please.

FIRST OFFICER: Approach, Loganair 67-80,

requesting descent to 1-1-0.

AIR TRAFFIC CONTROLLER: 67-80, descend to 1-1-0.

NARRATOR: The plane is more than halfway through

a 65-minute flight.

Most of the passengers live on the Shetland Islands.

FLIGHT ATTENDANT: All done?

SANNA AITKEN: Yes, thank you.

FLIGHT ATTENDANT: I'll take that.

NARRATOR: Many are returning home from holiday shopping in Aberdeen.

AITKEN: Air travel is massively

important, um, to residents in Shetland.

It's important for work meetings.

It's important for sporting events, for holidays.

It's the fastest way to travel off island, um,

so it's quick and convenient.

NARRATOR: The Captain is experienced.

He has more than 5,000 flying hours

and is the pilot flying tonight.

CAPTAIN (off screen): Passing flight level 1-5-0.

NARRATOR: The First Officer is monitoring the instruments

and handling all communications.

FIRST OFFICER: Approach, Logan 67-80.

Descending through flight level 1-5-0

for the I-L-S, runway 2-7.

NARRATOR: She has more than 1,000 flying hours.

HANS PETER GRAF: The crew had good total experience.

Of course, they didn't have a lot of experience

flying the Saab 2000,

but still it was a normal experienced crew.

NARRATOR: The Saab 2000 is a twin-engine high-speed turboprop.

It's a plane that aviation analyst Hans Peter Graf

knows extremely well.

GRAF: The Saab 2000

is the most advanced turboprop still existing and flying.

It has a jet-like performance paired with low fuel consumption.

And it had real good performance to fly in and out of mountainous terrain.

NARRATOR: They're traveling north from Aberdeen, Scotland,

to Sumburgh on the Shetland Islands,

a remote archipelago prone to winter squalls

and even hurricanes.

AIR TRAFFIC CONTROLLER: Logan Air 67-80,

for your information,

looks like the ATIS antenna at Sumburgh

has been struck by lightning so the system's not functioning.

I'll update conditions when I get them.

FIRST OFFICER: Okay, thanks for the update.

CAPTAIN: There's been a lot of that so far this winter.

NARRATOR: The ATIS, or Automatic Terminal Information Service,

provides pilots with continuous broadcast

of essential information.

GRAF: It broadcasts weather

and airport information every 30 minutes,

on which the pilots will base their approaches and landings.

CAPTAIN: Why don't you tune ATIS in anyway?

ATIS: Sumburgh, information Tango.

Winds two-niner-zero at 3-4, gusting 4-7. Visibility...

FIRST OFFICER: Guess it didn't get fried after all.

CAPTAIN: Gusting 4-7.

It's gonna get a bit rough on the way down.

NARRATOR: The winds at Sumburgh airport are blowing up to 47 knots,

54 miles an hour.

The crew will be facing strong gale force winds while landing.

AITKEN: I travel by air a lot.

It does get windy.

We were expecting a little bit of turbulence on the way.

We knew a flight of that size-- It's a small flight--

You do feel, um,

turbulence more than what you would on a bigger plane,

but it was nothing unusual.

NARRATOR: The captain wants to be ready for any unpredictable weather

thrown at them.

CAPTAIN: Let's brief in case of a lightning strike.

- FIRST OFFICER: Copy that. - CAPTAIN: Okay. Uh, right.

Instrument lights up full in case we get blinded.

Torches are here and here, on your side.

And the emergency elevator trim switch is overhead.

Any questions?

FIRST OFFICER: No questions.

MILLER: The statistics suggest that a particular aircraft

will probably get a lightning strike

about one and a half times a year.

You don't know when it's coming of course

and the thing you're aware of

is that these lightning strikes can affect the electronics

and the avionics in the aircraft.

CONTROLLER: Logan 67-80, fly heading 3-5-5.

Latest weather from Sumburgh, visibility 3300 now.

Moderate rain and snow. Runway is wet.

FIRST OFFICER: 3-5-5 for 67-80.

Got the weather too, thanks.

CAPTAIN: I'm gonna slow it down to 2-0-5

before we get into the chop.

FIRST OFFICER: Roger that.

NARRATOR: The crew prepares the plane for the turbulence ahead.

CAPTAIN: Let's get them buckled in back there.

(bell dinging)

NARRATOR: Sixteen miles from Sumburgh Airport,

Flight 67-80 turns onto its final approach to the runway.

(engine roaring)

FIRST OFFICER: Take a look at that.

CAPTAIN: I don't like it.

NARRATOR: There's some bad weather

developing off the end of the runway.

CAPTAIN: Approach, Logan 67-80.

There's a big storm cell on radar just off the runway.

We might need to discontinue.

AIR TRAFFIC CONTROLLER: 67-80, Roger. Let me know.

MILLER: All crews going into an airfield in these sorts of conditions

will be wary of the thunderstorm's activity around them.

NARRATOR: The pilots consider their options.

CAPTAIN: How much fuel do we have left?

FIRST OFFICER: 2500 kilos.

Do you want to head back to Aberdeen?

CAPTAIN: Let's circle, make another attempt.

GRAF: They abandoned the approach

when they saw a lot of precipitation

on their weather radar just ahead of them--

Updrafts, downdrafts, wind shears, which are not predictable.

So you better go around and wait or divert to another airport.

CAPTAIN: Logan 67-80,

we're gonna circle around, turning 1-8-0 for now.

AIR TRAFFIC CONTROLLER: 67-80, understood,

maintain 2000.

MILLER: He obviously made the decision that, at that time,

he would just turn away from the airfield

and probably allow that weather to pass through

and then have another approach.

NARRATOR: As the pilots circle for another landing attempt...

CAPTAIN: Oh! Crap!

(lightning cracking)

AITKEN: It sounded like a gunshot.

It was just a very short, sharp noise and a flash.

I thought at that point that it was something

that had happened to the engines.

GRAF: If you experience a lightning strike,

especially at night, it's a very bright light.

You can smell a burn smell, ozone smell,

and that sure is frightening or fearsome to every crew.

FIRST OFFICER: Circuit breakers look fine.

MILLER: After the lightning strike,

you're obviously looking to see, have we been damaged?

Are the instruments still working correctly?

CAPTAIN: I have control.

NARRATOR: But something's wrong.

CAPTAIN: The controls feel really heavy.

Damn it! The plane's not responding.

MILLER: There must be a degree of panic

that will set in when the controls are just not responding.

- CAPTAIN: The plane isn't responding. - FIRST OFFICER: Mayday, mayday,

this is Loganair 67-80. We've been struck by lightning

and are having control difficulties.

Please clear the airspace.

AITKEN: I knew that there was

definitely something not right.

I was terrified.

NARRATOR: Loganair flight 67-80 is in distress

2,000 feet above the North Sea.

FIRST OFFICER: Mayday, mayday, this is Loganair 67-80.

Please clear the airspace.

AIR TRAFFIC CONTROLLER: 67-80, copy.

If you can, souls on board and fuel remaining?

FIRST OFFICER: Thirty-three souls on board,

2,500 kilograms of fuel.

CONTROLLER: Copy.

All options are available. Do you want to land or divert?

NARRATOR: Without knowing what's wrong with the plane...

CAPTAIN: It's really fighting me.

NARRATOR: it's too risky to attempt landing in a storm

at Sumburgh Airport.

FIRST OFFICER: We should divert back

to Aberdeen. Better conditions.

CAPTAIN: Agreed.

NARRATOR: Aberdeen Airport is 190 miles away.

CAPTAIN: Let's try climbing to 4,000.

FIRST OFFICER: 67-80,

we're going to divert back to Aberdeen.

CAPTAIN: Something's wrong.

I can't get the plane to climb. How... how's your side?

FIRST OFFICER: It's really heavy.

Trim's not doing anything either.

GRAF: If you grab on the yoke

and the airplane is not responding, they realized,

hey, there's something wrong. We need to do something.

NARRATOR: Finally, the crew catches a small break.

FIRST OFFICER: Altitude is increasing.

CAPTAIN: Keep on it.

NARRATOR: The plane is climbing, but not as quickly as it should be.

CAPTAIN: The elevators might be damaged.

NARRATOR: In two minutes, the plane has barely climbed 2,000 feet.

The first officer worries the lightning strike

may have disabled their instruments.

FIRST OFFICER: Aberdeen 67-80.

What's our altitude?

AIR TRAFFIC CONTROLLER: I show you approaching

4,000 feet.

NARRATOR: But the controller is getting the exact same readings

as the crew.

CAPTAIN: We're really not going anywhere fast. Pull!

FIRST OFFICER: I'm almost all the way back.

MILLER: Let's face it.

You can fly an aircraft without a compass.

You can fly an aircraft without a radio.

But you can't fly an aircraft without functioning controls.

NARRATOR: And then, the unthinkable happens.

CAPTAIN: Oh no! Come on!

FIRST OFFICER: We're dropping!

NARRATOR: Flight 67-80 plunges uncontrollably

towards the North Sea.

AITKEN: The flight went into

that nosedive, so we knew immediately that,

that something wasn't right with the plane.

AIR TRAFFIC CONTROLLER: 67-80... 3800 now...

600... 3400...

NARRATOR: The pilots wrestle with their controls

as the plane speeds towards the water at 350 miles an hour.

AIR TRAFFIC CONTROLLER: You're descending.

Two thousand feet.

Eighteen hundred feet.

AITKEN: The dive was so fast,

you just felt like your heart was in your mouth.

I had no idea how close we were to the, to the sea.

You couldn't see anything. It was just pitch black.

It was terrifying. It was really scary.

AIR TRAFFIC CONTROLLER (off screen): Fifteen hundred feet.

You're descending.

FIRST OFFICER: Nothing's working!

CAPTAIN: Come on! Pull up!

NARRATOR: The airplane is less than ten seconds from impact.

MILLER: It must be incredibly frightening

because the pilots would be aware of their rate of descent.

They would be aware of their altitude.

And they would be aware of how much time left

they had to affect a recovery.

AIR TRAFFIC CONTROLLER: 1100.

FIRST OFFICER: Speed. Speed!

NARRATOR: In a last-ditch effort to save the plane,

the captain increases engine power.

(engine roaring)

CAPTAIN (off screen): We're climbing!

MILLER: So increasing the power

may increase the amount of airflow over the wings

and give you a little bit more lift to allow the aircraft

to pull out of its descent.

AITKEN: We were traveling at such a speed

that when the plane started pulling up again,

it was a kind of a sensation of being on a roller coaster.

It was definitely a relief to start climbing after that nose pitch.

NARRATOR: The pilots have avoided near catastrophe.

But now they need get their plane back to Aberdeen safely.

AITKEN: In the moments after that,

we had, uh, a period of just terrible turbulence,

the worst turbulence I've ever experienced.

The man behind me started vomiting.

Everybody was kind-- The flight was quite quiet though.

It was kind of eerily quiet.

FIRST OFFICER: Requesting fight level 2-4-0.

AIR TRAFFIC CONTROLLER: 67-80.

Roger. Climb and maintain 2-4-0.

FIRST OFFICER: The controls are working better now.

CAPTAIN: Ladies and gentlemen, this is the captain.

AITKEN: It was at that point the pilot came on and,

and told us we'd been struck by lightning and we were,

we were heading back to Aberdeen.

CAPTAIN: We had some flight control issues.

Everything is under control now.

We'll be landing in Aberdeen in 15 minutes.

And please expect to see some emergency services

on the ground when we land.

Not to panic.

It's just a standard precaution. Thank you.

AITKEN: When you go through a moment like that, you...

yeah, you panic until you're on the ground.

CAPTAIN: Let's fly a straight-in approach

and get this plane on the ground as soon as possible.

♪ ♪

NARRATOR: The pilots of Loganair flight 67-80

are on final approach to Aberdeen Airport.

FIRST OFFICER: Aberdeen, 67-80,

established on the localizer, runway 1-6.

NARRATOR: Not knowing which instruments they can trust,

the pilots carefully configure the plane for landing.

CAPTAIN: Flaps 35.

FIRST OFFICER: Flaps 35.

CAPTAIN: Control feels normal.

NARRATOR: Having avoided disaster twice already,

their sole focus is to get the plane safely on the ground.

FIRST OFFICER: One-thirty. Speed looks good.

Decision height.

CAPTAIN: Runway in sight. Continue.

AITKEN: The pilot came on and,

and told us we'd be expecting a normal landing

but the emergency services would be on the runway.

We weren't to be alarmed if we saw the lights.

CAPTAIN: All right.

50 knots. Coming out of reverse.

FIRST OFFICER: Check.

AITKEN: The landing was smooth in Aberdeen.

I was just glad that we were on the ground.

CAPTAIN: I'm happy to be on solid ground.

FIRST OFFICER: Me too.

AITKEN: I burst out into tears.

It was relief more probably than anything.

A little bit of shock probably too.

NARRATOR: It's up to investigators at the Air Accidents Investigation Branch,

or AAIB, to figure out what went wrong.

David Miller is the Deputy Chief overseeing the investigation.

MILLER: I decided that this would be a full investigation

because of the closeness this aircraft came to disaster.

We then dispatched a small team of investigators

to the operator's base to interview the crew

and to examine the aircraft.

NARRATOR: Very quickly, the flight data and cockpit voice recorders

are recovered from the Saab 2000.

LEAD INVESTIGATOR: Great work.

Let's hope they can provide some answers.

SECOND INVESTIGATOR: Let's hope.

MILLER: The normal process for an investigation

is the investigators take the recorders,

the cockpit voice recorder and the flight data recorder,

bring them back to the laboratories and recover the data.

LEAD INVESTIGATOR: It looks to be in pretty good shape.

SECOND INVESTIGATOR: Unusually so, yeah.

NARRATOR: Investigators need to confirm the crew's report

of a lightning strike

as well as the flight attendant's account

of seeing an orb of light pass through the cabin.

Ball lightning is a rare and little understood phenomenon

known to precede lightning strikes inside airplanes.

LEAD INVESTIGATOR: Right.

SECOND INVESTIGATOR: Well, there's no damage on the wing tip.

LEAD INVESTIGATOR: Mm-hmm.

MILLER: Lightning can strike more or less anywhere on an aircraft,

but it tends to strike on the leading edge of the wings

or the radome at the front of the aircraft.

SECOND INVESTIGATOR: There's soot marks on the radome.

NARRATOR: Investigators see signs of a lightning strike

on the nose of the aircraft.

SECOND INVESTIGATOR: It looks like some surface damage as well.

- LEAD INVESTIGATOR: Yeah? - SECOND INVESTIGATOR: Yeah.

MILLER: The point of strike will often leave scarring...

localized burning, sometimes a small hole.

LEAD INVESTIGATOR: Right. Let's see where it exited the aircraft then.

The elevators look fine.

Hang on.

Have a look at that exhaust cone.

SECOND INVESTIGATOR (off screen): Oh yeah.

LEAD INVESTIGATOR: That's where the lightning exited.

Look at it. Parts of it are completely melted.

FIRTH: And there was a little bit of burning damage

both to the front of the aircraft

and the exit point of the lightning strike,

which was at the very tail of the aircraft

where the auxiliary power unit exhaust was placed.

CAPTAIN: Oh! Crap!

NARRATOR: The team now knows how the lightning struck the plane.

CAPTAIN: The controls feel really heavy.

MILLER: So one of the first things to go and have a look at--

What was the effect of the lightning strike?

Were the systems damaged? Were there malfunctions?

LEAD INVESTIGATOR: Okay, you ready?

NARRATOR: The AAIB tests the plane's flight controls

to see if they're working.

LEAD INVESTIGATOR (on radio): Okay. Check the rudder.

Looks good. How about the elevators?

Yeah, elevators are working too. Everything checks out.

NARRATOR: Investigators are perplexed.

If the plane was functioning properly...

why did it become so difficult to control

after the lightning strike?

FIRTH: There were no abnormalities,

no system defects that we could find

either structurally or within the avionics.

Beyond that, it looked like a completely normal,

serviceable aircraft.

NARRATOR: AAIB investigators interview the pilots of flight 67-80.

FIRTH: When we're fortunate enough,

as in these circumstances, to have a surviving flight crew,

then their recollections are really important for us

to understand exactly how the event

progressed from their perspective.

LEAD INVESTIGATOR: So what happened after the lightning struck the plane?

CAPTAIN: After the lightning struck, the autopilot disconnected.

I have control.

FIRTH: The crew of the aircraft

became aware fairly shortly after the lightning strike

that the aircraft wasn't responding

as they expected to their flight control inputs.

LEAD INVESTIGATOR: And then what happened?

CAPTAIN: Well, we had control issues.

The plane wouldn't climb.

FIRST OFFICER: We tried everything and the plane wasn't responding.

FIRTH: The pilot flying was finding

that he was having to put

an increasingly strong backward effort on the control column

to raise the nose of the aircraft.

CAPTAIN: I can't get the plane to climb.

How... how's your side?

FIRST OFFICER: It's really heavy.

Trim's not doing anything either.

FIRTH: And the aircraft wasn't responding the way that he expected.

LEAD INVESTIGATOR: And then?

FIRST OFFICER: And then we entered a steep nosedive.

CAPTAIN: And the control issues continued.

♪ ♪

FIRST OFFICER: Nothing's working!

CAPTAIN: Come on!

Pull up!

FIRST OFFICER: Speed. Speed!

♪ ♪

CAPTAIN: It wasn't until after we'd increased power

that we were able to get the aircraft under control.

LEAD INVESTIGATOR: Really?

MILLER: Why did the crew believe

that they had control restrictions

and control problems

when in fact testing of the aircraft

showed there were no faults?

♪ ♪

LEAD INVESTIGATOR: Let's have a listen, shall we?

NARRATOR: Puzzled by the crew's account of the incident

onboard flight 67-80...

investigators turn to the cockpit voice recorder for answers.

MILLER: It will answer many questions

as to why things were happening the way they were

and how the crew were working together and interacting together.

FIRST OFFICER: Aberdeen ground, 67-80 taxiing on Whiskey

for parking stand seven.

NARRATOR: But something's not right.

LEAD INVESTIGATOR: Aberdeen? No.

This is from when they landed back at Aberdeen.

SECOND INVESTIGATOR: Right. Can you stop it

and go back to the top and play it again, please?

FIRST OFFICER: Aberdeen ground,

67-80 taxiing on Whiskey for parking stand seven.

LEAD INVESTIGATOR: That's all there is.

Well that's not gonna help us very much now, is it?

NARRATOR: The CVR has recorded over the critical moments of the flight.

It's a major setback for the investigation.

MILLER: We discovered that the cockpit voice recorder,

which only lasts for 30 minutes,

has been overwritten by subsequent events,

so there was no record of the crew conversation

and how they interacted with each other.

And so you have to look elsewhere for the information.

LEAD INVESTIGATOR: Right. This is what we know so far.

The lightning struck, the autopilot disconnected,

they had control problems.

Then, the plane did a nosedive.

SECOND INVESTIGATOR: Well, let's review the data.

LEAD INVESTIGATOR: Hmm.

NARRATOR: Will the data recorder provide

the answers they need to solve this case?

FIRTH: Flight data recorders often add

a level of detail that simply can't be gained from,

from the witnesses themselves,

and crucially quite often the information

that's gathered from a recording device

offers a slightly different perspective

to what we might get from personal recollections.

LEAD INVESTIGATOR: Stop.

This is where the lightning struck

at 2000 feet.

SECOND INVESTIGATOR: Right. And then for the next

two and a half minutes, there's a slow uneven climb

to 4000 feet.

And then they are in a very steep nosedive

for 20 seconds towards the North Sea.

LEAD INVESTIGATOR: That's 9500 feet per minute.

NARRATOR: Investigators are struck

by how close the flight came to total disaster.

LEAD INVESTIGATOR: It was seven seconds

from plunging into the sea

before they finally managed to pull out at 1100 feet.

FIRTH: The aircraft had a very high rate of descent

in the moments before it reached that height.

And so we were really very close to a very serious accident.

NARRATOR: What were the pilots doing to recover from the dive?

SECOND INVESTIGATOR: Look at the control column data.

LEAD INVESTIGATOR: Right after the lightning struck,

the crew pulled back on the control column

to pitch the nose up.

CAPTAIN: I have control.

The controls feel really heavy.

SECOND INVESTIGATOR (off screen): Look at the line.

I mean, they're having a very difficult time

getting that plane to climb.

FIRTH: We know from the data

that the aircraft climbed to around about 4,000 feet.

The pilot was finding that he was having

to put an increasingly strong backward effort

on the control column to, to raise the nose of the aircraft.

And the aircraft wasn't responding the way that he expected.

NARRATOR: The FDR data confirms

the pilots were tackling a control problem.

But why?

LEAD INVESTIGATOR: The Captain said they were

also applying pitch trim.

NARRATOR: Pitch trim moves the tail elevators

up and down to maintain the pitch of the aircraft.

LEAD INVESTIGATOR: Could we take a look

at the pitch trim data, please? Right.

NARRATOR: Investigators make a puzzling discovery.

SECOND INVESTIGATOR: Look at that.

The elevators are trying to get the nose

to pitch down instead of up.

NARRATOR: After the lightning strike,

some unknown force was fighting the pilots' inputs

to both the control column and the pitch trim.

MILLER: It's very difficult to imagine

what let's say an 80-pound force feels like.

Normal control pressures are much, much lower than that,

in the order of sort of 10 to 20 pounds.

So an 80-pound pull

is really extraordinary and very difficult to maintain.

CAPTAIN: Something's wrong.

I can't get the plane to climb. How...

how's your side?

FIRST OFFICER: It's really heavy.

Trim's not doing anything either.

FIRTH: We found that although the pilots were applying

a significant nose-up pitch control input

by pulling the stick back towards them, uh,

the aircraft was actually trimmed nose down.

Whatever was trimming the pitch control system

was effectively overcoming the effort of the pilots.

LEAD INVESTIGATOR: The crew said

the lightning struck, the autopilot disconnected,

and then they had control problems.

SECOND INVESTIGATOR: Right.

LEAD INVESTIGATOR: Could we take a look at the autopilot data, please?

NARRATOR: Finally, the team zeros in on the answer.

SECOND INVESTIGATOR: The autopilot was on almost the entire time.

FIRTH: The pilots themselves were very clear in their recollection

that it had disengaged.

All of the evidence we had indicated the autopilot

had in fact remained engaged.

LEAD INVESTIGATOR: It's no wonder the pilot had control problems.

The autopilot was set to keep the plane at 2000 feet.

SECOND INVESTIGATOR: Right. And whenever the pilots

tried to get the plane to climb,

the autopilot would engage and bring the plane back down.

LEAD INVESTIGATOR: Back to its assigned altitude.

NARRATOR: Investigators discover that after the lightning strike,

the pilots were in a tug of war with the plane.

CAPTAIN: I can't get the plane to climb.

How... how's your side?

FIRST OFFICER: It's really heavy.

MILLER: So we then had to look at why

did the crew misunderstand the status of the aircraft?

NARRATOR: The AAIB contacts the Captain of flight 67-80

to better understand why he thought the autopilot

disconnected when, in fact, it hadn't.

LEAD INVESTIGATOR: The Saab 340?

Okay. Thanks.

He said he assumed the lightning would disable the autopilot.

NARRATOR: The team learns the pilot trained for lightning strikes

on another airplane, the Saab 340.

GRAF: To change from Saab 340 to the Saab 2000,

you can say it's like changing from a motorbike to a bus.

All systems are different. Performance is different.

You're flying a totally different airplane.

MILLER: During the training on the Saab 340,

the commander had experienced a simulated

lightning strike to that aircraft,

which caused both generators to fail.

And, in doing so, would cause the autopilot to disconnect.

CAPTAIN: I have control.

MILLER: So when the lightning strike happened for real,

his first thoughts were, "The autopilot has failed."

CAPTAIN: The controls feel really heavy.

MILLER: "I must control the aircraft myself."

And in fact, the lightning strike had had minimal effect on the aircraft.

SECOND INVESTIGATOR: Would you pull up the control data column again, please?

NARRATOR: If the lightning didn't disconnect the autopilot,

investigators wonder why it remained engaged

for more than two minutes

as the pilots struggled with the controls?

LEAD INVESTIGATOR: Wouldn't the force applied

to the control column

and the pitch trim have overridden the autopilot?

MILLER: Now in most aircraft,

if the pilot intervenes on the controls

and tries to apply a force against the autopilot,

the autopilot is designed to disengage.

FIRTH: One way of thinking about this

is to imagine you're driving down the highway

in a car on cruise control

and you're getting close to a car in front of you,

so you press the brake.

And what you expect to happen is for the car to slow down.

You don't expect the cruise control to, uh,

oppose the brake and add more power to maintain 65 miles an hour.

But that's essentially what was happening in this case.

NARRATOR: The autopilot was attempting

to keep the plane at 2,000 feet

despite all attempts by the crew to climb.

LEAD INVESTIGATOR: It says here applying an override force

to the column will not cause the autopilot to disengage.

GRAF: In the Saab 2000, the autopilot would not disconnect

when you exert force on the control columns.

LEAD INVESTIGATOR: There's more.

"Pressing the main pitch trim switches

also has no effect to cause the autopilot to disengage."

NARRATOR: The team is surprised to discover there is no force override

for the autopilot in the Saab 2000.

CAPTAIN: Something's wrong.

I can't get the plane to climb.

MILLER: One thing the pilot would have done is as he pulled back

and feeling the force on the control column,

he would have used the switches on the control column

to apply trim in the appropriate way.

CAPTAIN: How's your side?

FIRST OFFICER: It's really heavy.

Trim's not doing anything either.

MILLER: But when the autopilot's engaged

in this model of aircraft, the trim switches are inhibited.

So no matter how much they selected those trim switches,

they were having absolutely no effect.

NARRATOR: Investigators soon discover that the Saab 2000 is unique.

SECOND INVESTIGATOR: Look at that. There.

NARRATOR: It's one of the few planes in existence

that doesn't have an autopilot override.

LEAD INVESTIGATOR: Every plane has an autopilot

override function, except for the Saab 2000.

FIRTH: It just had a different design

to all the other aircraft we were aware of.

And really to discover that the autopilot had greater authority

than the, the human pilots was a bit of a revelation for us.

NARRATOR: It still doesn't explain why the crew

didn't know the autopilot was on almost the entire time.

LEAD INVESTIGATOR: Wouldn't there be some sort of indicator in the cockpit?

SECOND INVESTIGATOR: Yeah. I'll show you. Look over here.

FIRTH: When the autopilot is connected, that will be a green AP.

LEAD INVESTIGATOR: Well what does the control panel

look like when the autopilot goes off?

SECOND INVESTIGATOR: Like this.

FIRTH: When that autopilot is not connected,

it will be a white AP but the letters AP remain.

- LEAD INVESTIGATOR: That's it? - SECOND INVESTIGATOR: That's it.

It just goes from green to white.

MILLER: One could argue whether that visual clue

is enough to warn the crew of the status of the,

of the autopilot.

CAPTAIN: I have control.

MILLER: It's not as if the AP disappears

when it's not engaged and appears when it is engaged.

CAPTAIN: Oh no. Come on!

FIRST OFFICER: We're dropping!

MILLER: But all we have here

is a color change between green and white.

And that sometimes is very difficult to perceive

when you're in a high-stress situation.

NARRATOR: Investigators believe that the autopilot visual indication

might have been too small for the pilots to see

as they struggled to control their plane.

LEAD INVESTIGATOR: Surely there would have been aural warnings?

Yes. Right here. It says, the plane's computer

would have sounded a caution chime.

NARRATOR: Even if the pilots missed the visual indications

for the autopilot,

caution chimes would have alerted them

when they adjusted the pitch trim.

LEAD INVESTIGATOR: The Captain never said anything

about hearing any chimes.

SECOND INVESTIGATOR: Right. So what's going on then?

AIR TRAFFIC CONTROLLER: 67-80, 3800 now.

MILLER: If they are trimming against

the autopilot for more than ten seconds,

a chime will announce to say

that there is a pitch mis-trim situation.

FIRTH: We see from the data

that it's highly likely that the alerts would have occurred,

but the crew don't recall having heard them.

FIRST OFFICER: Nothing's working!

CAPTAIN: Come on.

NARRATOR: So why did the pilots of flight 67-80 ignore all warnings

telling them that the autopilot was in control?

NARRATOR: AAIB investigators have learned

that after a lightning strike,

the crew of Loganair flight 67-80

didn't recall hearing audible warnings

that the autopilot was engaged and set to maintain 2,000 feet.

LEAD INVESTIGATOR: Lightning struck the plane

and for two and a half minutes

the crew struggled with the controls

to get the plane to climb.

SECOND INVESTIGATOR: Right. They were so distracted

by that, they failed to see what was really going on.

LEAD INVESTIGATOR: Could the stress have affected

their perception of the situation?

MILLER: We have to bear in mind, of course, this was at night,

in turbulent, poor weather, heavy rain.

And the lightning strike would have been really quite bright,

and the noise would have been alarming.

So it's sort of understandable

that their performance was degraded

because of the stress situation.

- CAPTAIN: And I have control. - (alarm blaring)

FIRTH: A couple of things happen

when we get stressed.

We tend to focus on fewer and fewer things, uh,

and we tend to not notice the other things,

and that can be either visual cues or auditory cues.

So we get what's called "cognitive tunneling,"

and one aspect of that is an intentional deafness

so, um, an alert might occur but we might not hear it.

(alarm blaring)

MILLER: It's very difficult for a crew

to break the vicious circle of cognitive tunneling

tunneling where they're concentrating on one event

and not looking at the bigger picture.

CAPTAIN: The controls feel really heavy.

NARRATOR: But if the pilots were suffering from cognitive tunneling,

how were they able to regain control of the plane?

SECOND INVESTIGATOR: Okay. Look at this.

NARRATOR: The AAIB makes one last horrifying discovery.

SECOND INVESTIGATOR: The only reason the autopilot

ever disengaged

was because of a random glitch in the plane's computer system.

FIRTH: The reason for the disconnection

was that there was a momentary loss of data

to the air data computer.

And we know that's one of the conditions

that would cause the autopilot to disconnect.

And that's what caused it to disconnect in this case.

GRAF: Had the autopilot

disconnected more than seven seconds later,

the airplane would have gone into the ocean,

in a dive at over 300 knots.

This wasn't a fatal accident by pure luck.

NARRATOR: Investigators believe they finally understand

what caused the terrifying incident

onboard Loganair flight 67-80.

While circling away from a bad storm at Sumburgh Airport...

CAPTAIN: Roger that.

We'll wait until the storm's over.

NARRATOR: ...the crew is startled and disoriented

by a lightning strike.

In a moment of high stress,

the captain believes the autopilot has disengaged...

CAPTAIN: I have control.

NARRATOR: ...when it hasn't.

FIRTH: The autopilot remained engaged and they didn't realize that was the case,

so effectively from that point until it disengaged,

they were fighting the autopilot.

They wanted to climb. It wanted to descend.

And because of the way the flight controls were configured,

the autopilot was going to win.

NARRATOR: Engaged in a tug of war with the aircraft,

cognitive tunneling takes over.

CAPTAIN: Something's wrong.

I can't get the plane to climb. How...

how's your side?

NARRATOR: The highly stressed pilots

don't register the audible warnings

telling them that the autopilot is still engaged.

FIRST OFFICER: It's really heavy.

The trim's not doing anything either.

NARRATOR: The final blow is a one-of-a-kind autopilot system

without a force override.

MILLER: I have every sympathy for crews

being startled when something unusual happens,

whether there's an explosive engine failure,

or a lightning strike in this case.

But the training must kick in and the crew must revert to,

in effect, as I say, sit on your hands for a few moments,

make an assessment of what's happened, what's gone wrong,

what's working, what's not working

and then deal with the situation from there.

CAPTAIN: Oh no! Come on!

FIRST OFFICER: We're dropping!

NARRATOR: If it wasn't for a split-second fluke error

in the computer system

and the relentless efforts of the crew...

FIRST OFFICER: Speed. Speed!

NARRATOR: ...flight 67-80 would have slammed into the North Sea

at 380 miles per hour.

AITKEN: I would say I was a nervous flier for a couple years.

So I've just kind of gone through the motions

of sort of building myself up

to knowing that it's gonna be fine.

NARRATOR: The final report recommends several safety changes

to the autopilot system.

FIRTH: We then made recommendations

looking at how aircraft could be certified in future

to make sure that no future design could be certified

where neither operation of the control column

nor operation of the pitch control switches

would result in disconnection of the autopilot.

NARRATOR: For investigators, the lessons of Loganair 67-80

go beyond this one near tragedy.

FIRTH: We can only go so far

in educating human operators in how a system works.

Ultimately, we have to recognize that they will behave instinctively,

particularly when under stress.

That's the real challenge for the future of automated systems.

Captioned by Point.360