NARRATOR: On approach to a remote town
- in Indonesia's Papua province... - Gear down.
..a turboprop plane vanishes.
Trigana 267, Oksibil. Do you copy?
TRANSLATOR: We tried to think positively
that there's a chance the aircraft ended up landing at
a different airport with limited communication.
Overseas, a search is underway for an Indonesian plane carrying
more than 50 people...
A treacherous climb up a steep mountain leads
to the worst possible news.
We've reached the crash site. No survivors.
The number one priority is to find the black boxes.
With no clues,
investigators hope the damaged black boxes will solve this puzzling case.
Can you turn that up?
That's it?
Mayday, mayday!
'Pull up.'
(GARBLED RADIO TRANSMISSIONS)
NARRATOR: Sentani Airport in Papua province, Indonesia.
Trigana Air Service pilots Captain Hasanuddin and First Officer Aryadin
are on a short layover before their fifth flight of the day.
What have we got? Like 20 minutes?
About that, yeah.
I think I'll get up and stretch my legs.
- Want anything from the terminal? - I'm OK, thanks.
OK.
The pilots have already flown four short flights today in Papua.
This leg will take them to a remote airport in the Oksibil area.
Typically, the flights of a commuter aircraft will be
an hour or less. So the typical duty day for a pilot might include
four or more take-offs and landings.
It's challenging in the sense of, taking off and landing are the most
risky parts of any aircraft flight, and doing so several times in a day
could put different kinds of stresses on a pilot.
Hello.
Flight attendant Dita Amelia Kurniawan...
Good afternoon.
..has been with Trigana Air Service
for three years and knows many of the regulars who fly this route.
Good to see you again.
49 passengers will be making the short trip to Oksibil.
Oksibil is a very remote area,
so most of the passengers would be local government officials,
local businessmen.
Very few tourists go to Oksibil.
Do you wanna switch on the way back?
No, I'm good for one more leg.
- All set back there, Dita? - Good to go.
Thank you, Dita.
At 2:22pm, Flight 267 takes off.
Landing gear up.
- Landing gear is up. - Flaps set to zero.
Flaps zero.
The flight to Oksibil takes 40 minutes.
The estimated arrival time is 3:04pm.
We're at 2,000 feet. Wanna turn on the autopilot?
Autopilot engaged.
The pilots are flying an ATR 42-300,
a twin-turboprop short-haul aircraft.
The ATR 42 is a medium-capacity commuter-type aircraft.
They're popular because they can get into smaller airports -
places where you can't really get
an airplane that's a 737 or 747 size into and out of the airport.
Minutes later, the plane reaches its cruising altitude of 11,500 feet.
Water?
The flight is so short...
I'll call Oksibil.
..the captain is already preparing for the descent into Oksibil.
Oksibil, Trigana 267.
- Trigana 267, Oksibil, copy. - We are beginning our approach.
We would like to descend from 11,500 feet.
Confirm descent from 11,500.
Let me know when you are positioned over Oksibil.
Oksibil is a small airport situated in a valley.
The mountains surrounding it can reach 11,000 feet.
Decreasing engine thrust.
244 knots and dropping.
Oksibil Airport is in a mountainous area. It sits in a valley.
And on top of that, they have very limited
navigational aids at that airport.
Without the aid of advanced landing systems seen at bigger airports,
pilots flying into Oksibil must keep
the runway in sight during the approach.
A visual approach, as the name implies, is an approach where
the flight crew has to have the airport and the surrounding
area in sight.
Cabin crew prepare for landing.
In preparation, please straighten your seatback and stow your tray.
I'll be coming around to collect any garbage you may have.
Big plans with the family?
Yeah, looking forward to some time off.
Yes. It's been very busy these past few weeks.
Flaps 15.
Gear down.
Wings Air 1250, confirm descent from 12,000.
Report when you are positioned over Oksibil.
Five minutes later,
the air traffic controller at Oksibil realises Flight 267
hasn't reported in as expected.
Trigana 267, Oksibil. Do you copy?
One of the common things that happens,
when an airplane doesn't land at an airport
for some reason, is they may divert to another airfield.
The crew landing the aircraft may have been too busy to call
the airport before diverting to another airfield.
Hey, this is Oksibil. We've lost contact with Flight 267.
Have you heard from the pilots?
You haven't?
We might have a problem here.
Word of the missing plane travels fast.
Overseas, a search is underway for an Indonesian plane
carrying more than 50 people.
The flight lost contact today over a remote area of the country.
As the news spreads, investigators with Indonesia's
National Transportation Safety Committee, the KNKT, fear the worst.
My first impression was
that something wrong had happened.
It's not looking good.
Well, maybe they just diverted and haven't checked in yet.
TRANSLATOR: We tried to keep
thinking positively that there's a chance the aircraft
suffered from some damage
and ended up landing at a different airport with limited communication.
A search and rescue team is assembled,
consisting of army soldiers and search and rescue personnel.
TRANSLATOR: They immediately began the search around Oksibil airport,
because we learned from air traffic control
that its last location was quite close to the airport.
Flight 267 was only 15 miles from Oksibil airport when it last
checked in with air traffic control.
But search efforts come up empty...
until a pilot flying out of Oksibil airport
spots smoke billowing from nearby Tangok Mountain.
TRANSLATOR: We don't have a lot of information.
We can only hope that the people onboard have survived.
The day after,
a pilot reports seeing smoke in the mountains
surrounding Oksibil, Indonesia.
The crash site of Trigana Flight 267...
is located.
(PHONE RINGS)
Yeah.
140 degrees, 29 minutes. 51.18 seconds east.
OK, got it. Thank you.
The wreckage is at approximately 8,300 feet
on a ridge of Tangok Mountain,
10 nautical miles from Oksibil Airport.
They went off course. How did they end up over there?
We need to get eyes on that crash site.
I'm gonna send one of our guys up.
A search and rescue team takes a KNKT investigator to the crash site.
At over 4,000 feet above ground level,
there are no roads, runways or clearings.
The only way to get to the crash site is on foot.
To reach the area, the team had to walk for about four and five hours.
They had to climb in a quite steep - the dense vegetation.
It's quite hard to get to the site.
After climbing for five hours...
the team finally reaches the crash site.
A field of debris stretches through Tangok's thick forest.
Go ahead, Oksibil.
Jakarta, we've reached the crash site.
No survivors.
OK. Once you catch your breath, the number one priority
is to find the black boxes.
OK.
Hey, guys. Check it out.
We're looking for the FDR and the CVR.
Because of the remote location, bringing much of the wreckage down
from the mountain will be impossible.
So the investigator at the scene must document as much as he can
and send photos back to headquarters.
While the search and rescue team
retrieves the remains of the 54 people that died,
the KNKT investigator tries to determine exactly how the plane
hit the mountain.
The trees surrounding the crash site provide an important clue.
They are sheared-off in a straight line,
indicating the plane flew head-on into the mountain.
That's right. There's no sign they pulled up.
How could the crew have flown
straight into a mountain that's so well known to pilots?
The investigation team's top priority will be to figure out what
was happening in the cockpit at the time of the crash.
The plane's flight data recorder and cockpit voice recorder
can be invaluable tools for the investigation.
The damaged black boxes are shipped out for analysis.
In the days that follow...
family members mourn while they wait for the recovery of loved ones.
TRANSLATOR: Search and rescue, along with the local help,
have been successful in retrieving the 54 bodies.
They are desperate to know what caused the crash
that killed everyone on the flight.
It's up to KNKT investigators to figure that out.
They first need to determine why the plane ended up off-course.
Blue's the flight path in the approach chart.
Here's where they crashed.
Flight 267 crashed about 10 miles west
of the approach path into Oksibil Airport.
They went right and ended up here.
I'd like to know more about the terrain around here.
To determine the height of the terrain along the flight's path,
investigators use special software that generates
topographical data for the area.
TRANSLATOR: When we learned about
the location of the crash, we had some difficulties.
We realised it would be a challenge for us
to identify the terrain height of the plane's debris.
The topographical map reveals that the pilots were flying
a treacherous route.
They were surrounded by mountains as high as 9,000 feet.
Why didn't they fly above them?
Investigators wonder if there was a mechanical problem
with the plane that caused it to plough into a mountain.
Maybe the FDR can tell us.
Certainly there would have been something in
the flight data recorder that may have given an indication
that some system on the aircraft wasn't operating as it should have.
When the recovered flight data arrives,
Nurcahyo and Wibowo are eager to get their first look at how
the plane was functioning at the time of the crash.
Wait a minute.
This doesn't make any sense.
This says the plane was going east, not south.
TRANSLATOR: We were able to download this data that contained
all the flight information,
but the flight data we recovered didn't correlate
with what might have happened on the day of the crash.
And the time of day is wrong. So is the speed.
TRANSLATOR: The flight data was not from the day of the accident.
Digging even deeper into the data,
the investigators come to a disturbing realisation.
The recorder wasn't working at the time of the crash.
Useless.
We found that the FDR had been experiencing several
problems since 2012.
It had been installed on that aircraft and found fault and then
offloaded, went to the shop for repair, back again to the aircraft.
The malfunctioning FDR
had no connection to the accident, making it much harder for
Nurcahyo and Wibowo to figure out what caused it.
Investigators still don't know why Flight 267...
slammed into the side of a mountain.
In the Indonesian province of Papua,
the families of the 54 people onboard Trigana Flight 267
lay their loved ones to rest...
including flight attendant Dita Amelia Kurniawan.
Overcome by grief, they want answers as to what happened.
Authorities have released new pictures showing
the wreckage from the Indonesian passenger plane
that crashed in the country's remote eastern region over the weekend...
KNKT investigators are facing intense pressure to determine
why Flight 267 crashed.
Without recorded flight data,
the plane's cockpit voice recorder is investigators' last hope to learn
what was happening in the air at the time of the crash.
They would be able to understand what was said
to and from air traffic control,
and they can also understand any kind of communication -
formal or informal - that was taking place within the cockpit.
That can be a huge indicator of something going wrong
with that flight.
Fortunately, the CVR data is successfully recovered.
Alright. We're ready?
OK, play it.
The CVR contains two hours of audio, including from the two flights
prior to the accident flight.
PILOT: I'll call down and let them know we're coming.
Investigators first listen to the pilots' flight into Oksibil
from earlier in the day, in the hopes of finding clues.
Oksibil, Trigana 267.
- Trigana 267, Oksibil, copy. - We're beginning our approach.
We would like to descend from 11,500 feet.
Confirm descent from 11,500.
Let me know when you are positioned over Oksibil.
Uh, Oksibil, we won't be over the airport.
We're going to fly direct to a left-base leg to runway 11.
- Copy that. - Left-base leg?
That's not what it says in the charts.
They took a shortcut?
The CVR reveals that the pilots made an intentional deviation
in their approach during their prior flight into Oksibil.
The official approach directs aircraft to fly over the airport
and then circle back and land.
But on the earlier flight, the pilots flew directly to runway 11
without looping around.
500 feet. Landing flaps and propeller speed
are set and confirmed.
After flying the shorter approach,
the pilots landed on the runway at Oksibil...
without incident.
Investigators wonder if the pilots tried to repeat that
shorter approach a few hours later but with a very different result.
Let's skip ahead to the accident flight.
PILOT: We're at 2,000 feet. Wanna turn on the autopilot?
Autopilot engaged.
AIR TRAFFIC CONTROLLER: Confirm descent from 11,500.
Let me know when you are positioned over Oksibil.
Oksibil, we're flying direct to a left-base leg to runway 11.
Copy that.
So they take the same shortcut for the accident flight.
The last flight proceeds much like
the crew's earlier flight into Oksibil.
PILOT: Big plans with the family?
Investigators listen closely for any signs of danger.
Yeah, looking forward to some time off.
It's been very busy these past few weeks.
It's what they don't hear that raises questions.
They're not doing their approach briefing and checklist.
Briefings and checklists serve several functions.
One of the key functions is to give
the flight crew a better understanding of their environment.
Not doing that makes it less likely that the pilot will remember
to do certain things,
or to take certain precautions, or to be aware of certain hazards
that could be happening on that particular flight.
The team now knows that the crew missed a crucial step
on their approach.
But can the recording reveal anything about
how the plane was functioning mechanically just before the crash?
Can you turn that up?
(SOUND OF PLANE'S ENGINES ON RECORDINGS)
Picking up anything with the engines?
TRANSLATOR: We tried to analyse the sound of the engine.
Flaps 15, gear down.
TRANSLATOR: Based on the frequency and amplitude of the sound
of the propeller, we concluded that the engine
and propeller were both in good shape.
Nothing unusual.
On the last phase of the flight, the CVR recorded that the condition
in the cockpit was normal.
While listening to the final moments of the crash,
investigators make a baffling discovery.
(RECORDING ENDS)
That's it?
Normally at the last second of the flight the pilot would have
been scream or do something.
It happened so fast. It sounds like they didn't even see the mountain.
Investigators have a theory about the crash of Trigana Flight 267.
They believe that weather
may have obscured the pilots' view of the mountain.
The team scrutinises weather data recorded less than
an hour before the crash.
Oksibil was covered by dense clouds.
The data reveals that, at the time of the accident,
Flight 267 would have been flying through an area of low clouds.
The clouds could have been quite dense here.
The pilots wouldn't have been able to see much.
Yeah, but you know Papua.
You never really know what the weather's gonna be like
unless you're looking out the window yourself.
It is difficult to determine
whether the flight was in cloudy conditions or not.
In the mountainous area, it can be cloudy in one valley,
it can be perfectly clear in another valley, and you go into another
valley and it's completely covered.
To get a first-hand account of the weather conditions
on the day of the accident,
investigators speak to the controller on duty.
What was the weather like on their first flight into Oksibil?
It looked mostly clear.
And did the weather change on their second flight?
Yeah. The clouds rolled in.
It was so dense that I couldn't even see the mountains.
The controller tells the investigators that
he did inform the pilots about the cloudy conditions.
Oksibil, Trigana 267.
Trigana 267, Oksibil. Go ahead.
How's the weather looking for our approach?
You've got a cloud base of 8,000 feet.
The pilots' decision to continue flying with so much cloud cover
surprises investigators.
TRANSLATOR: In principle, when flying using visual rules,
only one rule applies - to arrive safely, you must maintain
visual contact at all times.
Gear down.
The visual approach is not allowed to be done in a cloudy condition,
so when the cloudy condition and they're unable
to see the whole mountain, they should follow the procedures.
But instead of following procedure...
They knew the base of the clouds was 8,000 feet.
..they took a gamble
that they would eventually catch sight of the runway.
They were descending,
expecting to drop out of the clouds at any minute.
Instead, they crash into a mountain
at 8,300 feet.
We still don't know why they didn't know they were
in the path of a mountain.
With modern aviation technology, even if the pilots didn't see
the mountain, the plane should have.
So why didn't they know they were heading straight into one?
We need to check their warning system.
TRANSLATOR: When a plane is in close proximity to terrain
or about to hit an object,
there's a warning system that warns the pilot when the plane
is very close to terrain.
The warning system uses GPS and a terrain database
to monitor an aircraft's height above the surrounding terrain.
If the plane comes too close to the ground, the system will warn
the flight crew with audio messages...
'Terrain. Terrain. Pull up.'
..so pilots know to increase their altitude.
This is the profile of the mountain.
This is our flight descending through clouds,
and the pilots can't see the ridge in front of them.
Their proximity to the terrain would have activated
the terrain caution here, 60 seconds before impact.
Now, the pull-up warning should have gone off here,
30 seconds before.
Were there any warnings going off in the cockpit?
No. There's nothing in the transcript.
The absence of audible alerts leads investigators to wonder
if the plane's warning system was working properly.
The team knows the FDR wasn't properly maintained.
Could the same be true for the warning system?
TRANSLATOR: We tried to dig deeper to see if the warning system
had been properly installed in Trigana 267.
Last maintenance was performed on August 14,
two days before the crash. It appeared to be working normally.
TRANSLATOR: When we looked into the maintenance record,
we did not find any significant mention of something broken
in the warning system.
With a faulty warning system ruled out, investigators
now wonder if the terrain data used by the system was accurate.
This area is not very well mapped.
Some of the Papua area was very rough data.
The precision of the data was not as close to
the actual conditions.
If you fly in a mountainous area, the database itself
might not detect the fine details of the contour
of the terrain around you.
Did the lack of accurate terrain data mean the system wasn't able
to warn pilots when they were too close to the mountainous terrain?
The Trigana 267 investigators decide to speak with
Trigana pilots who regularly fly in
the Oksibil area to find out if they received terrain warnings.
The pilots report that not only did the system provide warnings,
it gave an excessive amount of false warnings
due to the poor-quality data.
If you're flying within a mountainous area,
it can give you a false warning or unnecessary warnings.
Was this area prone to false alarms?
Imagine you are trying to land in a small airport
in the middle of the valley.
You can see the airport in front of you. You're in visual conditions,
and then the system starts giving you a warning.
'Terrain. Terrain. Pull up.'
You think, "Well, I can see the airport in front of me.
I can see the terrain behind it. That warning is annoying."
And what do you normally do when you keep getting
these false warnings?
Hold on.
He says sometimes they deliberately pull the circuit breaker.
- Sorry, go on. - It's an astonishing finding.
It might have been because of spurious or inappropriate warnings
by the system. That is, it's telling you that
you're close to the ground when in fact you're not.
This is what I like to call the boy who cried wolf syndrome.
'Terrain. Terrain. Pull up.'
You know, the other flights we've done, we've had no problem.
Let's just turn this thing off.
'Terrain.'
But if you pull the circuit breaker,
you might forget that you've pulled it.
And that's not good, because if you're going into a valley
when it's still cloudy, you still need your systems
no matter how unreliable that is.
Any warning you get, if you don't have visual contact with
the ground, you follow it.
OK, thank you.
They just pull the breaker to get rid of the false warnings.
- Apparently it's common practice. - Are you kidding me?
This revelation leads investigators
to ask themselves a difficult question.
Did Flight 267 lack terrain warnings...
because the pilots intentionally turned the system off?
Both the captain and the first officer were very experienced.
In fact, I think these pilots were much more experienced
than the average turboprop pilot.
We've reached cruising altitude, 11,500.
TRANSLATOR: Is it possible the pilots were overconfident
because they had flown this route so often?
We also asking questions to some pilots, particularly pilots that
had experience flying with these two accident pilots.
Will you excuse me?
I now have a pilot on the line that says he's personally seen
Captain Hasanuddin pulling the circuit breaker.
We found some information that some co-pilots flying with
the captain knew the captain had the habit to inactivate the system.
Decreasing engine thrust.
'Terrain. Terrain. Pull up.'
- Yeah, yeah, yeah. - 'Terrain. Terrain.'
Overconfidence and complacency are two of the issues that are common
in aviation, and what it leads to is certain equipment could be
turned off because the pilots think that their experience in
other aspects of flight will more than compensate.
- 'Terrain. Terrain.' - Yeah, yeah, yeah.
When a flight crew operates deliberately with an aircraft
that's not fully capable, they're increasing the risk of that flight.
Looking through the captain's records, investigators discover that
the airline knew about his habit of pulling the circuit breaker.
Hmm.
It says here that they scheduled a briefing with him to address it.
Based on this information, we assumed that that day,
on the accident day, the captain also inactivated the system.
'Terrain. Terrain. Pull up. Terrain. Terrain.'
- I got this. - 'Pull up. Terrain. Terrain.'
'Pull up.'
Investigators now believe that the pilots intentionally
disabled their warning system on an earlier flight that day
and then never reset it.
If the system was active, I'm sure that the accident would have been
avoided because the last seconds of the flight before the impact,
the system will scream, "Pull up, pull up."
The pilot would have taken action to save the flight.
No wreckage relating to the warning system
is recovered from the crash site.
Investigators can't know for sure if the circuit breaker had been pulled.
But even if the pilots were overly confident
they could make the approach without the aid of the warning system,
there's still something else that doesn't add up.
The pilots flew into this area all the time.
Why were they flying so close to the mountains in the first place?
Investigators are trying to determine
why pilots who were very familiar with the Oksibil area
would risk flying so close to the mountains below them.
Can you pull up this approach chart?
A diagram in the corner of the approach chart informs pilots
about the safe minimum altitudes in areas surrounding the approach path.
The approach chart says the minimum safe altitude
in this area is 8,000 feet. Flight 267 crashed at 8,300 feet.
They were adhering strictly to the information that was there
in the approach chart, but the information was wrong,
and that wrong information put them at risk for colliding with terrain.
We're good to 8,000 feet.
Investigators believe the pilots were aware
of the minimum safe altitude published on the approach chart.
It's the last piece of the puzzle.
The crew thinks they're safe down to 8,000 feet.
And on the accident day, the base of the clouds is 8,000 feet.
It makes the pilots feel as long as they're in the clouds,
they're safe.
Decreasing engine thrust.
244 knots and dropping.
Cabin crew, prepare for landing.
What struck me more than anything was that this
was so very preventable.
This was a controlled flight into terrain event.
The investigation has uncovered a confluence of factors that led to
the crash of Flight 267.
Big plans with the family?
Yeah, looking forward to some time off.
It's been very busy these past few weeks.
At the core - two pilots who
had grown overconfident flying the route so many times before.
'Terrain. Terrain. Pull up.
- 'Terrain. Terrain...' - I got this.
'Terrain. Terrain...'
Because the captain had a reputation for pulling the ground proximity
warning system circuit breaker, investigators suspect he disabled
the system on an earlier flight that day.
Then, on the last flight into Oksibil...
We're beginning our approach. We would like to descend
from 11,500 feet.
Confirm descent from 11,500.
Let me know when you are positioned over Oksibil.
Gear down.
..the pilots failed to do their approach briefing
or safety checks and relied on faulty approach charts.
There are three key things that could have avoided this accident -
adherence to standardised procedures,
the use of warning systems, and the use of cockpit resource
management techniques, which could be as simple as
is there a checklist that should be used?
Three very clear areas where any one of them
would have prevented this accident. None of them happened.
In the aftermath of Flight 267, the KNKT makes a series of
safety recommendations that will make the skies of Indonesia safer.
First of all, the charts needed to be updated.
TRANSLATOR: We also asked the airline operator
to request the database for the warning system to be updated
with a more accurate version.
Up to now we noticed a significant drop in warning system violations.
Also, since the approach chart for Oksibil has been fixed,
we've seen a positive impact in terms of flight safety in Papua.
The lessons from this accident,
the insights from the investigation won't go away.
They'll be here decades from now.
I'm confident that the insights
in this report will influence design of equipment,
will influence the design of procedures, will influence
the kind of hazards that flight crews
will look out for in the future.
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