- [Petter] Aircraft accidents

are always caused
by a combination

of several factors and the thing

that gets the sequence rolling

is often something
simple and mundane.

But this is the
first time I've ever come

across a single letter kicking it off.

- [GPWS] Sink rate. Pull up.

- Stay tuned.

When you hear the word Tenerife

in aviation context,
people almost always think

of the world's worst aviation disaster,

the collision between two Boeing 747s

at Tenerife's Los Rodeos
Airport back in 1977.

But the island of Tenerife,

the largest of Spain's Canary Islands,

actually suffered a string of disasters

between the 1950s and 1980s,

who collectively claimed 950 lives

and that infamous runway collision

was just the worst one of those.

So today I will tell you the story of

the last major
incident to happen there,

a story that took place on
a rainy spring day back in 1980.

And this one, I think a lot
fewer of you have ever heard of.

In the morning of the 25th of April 1980,

the crew of Dan-Air Flight 1008

were preparing to depart
from Manchester in England

on a charter flight,
bringing tourists down

towards Tenerife North Airport,

then known as Los Rodeos.

During the 1970s and '80s,

Dan-Air was one
of Britain's largest operators

of inclusive tour flights,
chartered by tour operators

to transport fixed groups of people

down to popular holiday destinations

in Southern Europe and North Africa.

Among the aircraft types operated

by Dan-Air was the mighty Boeing 727,

and Dan-Air were
actually the first British airline

to import this model,
which had then had

to undergo several unique modifications

in order to
meet British safety standards.

Now it would later turn out

that the 727s were a
financial disaster for Dan-Air,

but by 1980, that was
not yet very obvious.

The aircraft that the
crew were going to operate

on this day was 14 years old

in generally good condition

and could seat a
maximum of 144 passengers.

So with a total
of 138 passengers booked,

it was almost completely full.

The crew consisted
of five flight attendants

and three pilots, meaning that in total,

there were going
to be 146 people on board

once the flight got on the way.

The pilot in command was a very

experienced 50-year-old captain

who had around
15,300 total flight hours,

which included almost 2,000
on the Boeing 727.

He had flown this route
down to Tenerife North

a full 58 times before this flight,

making him very familiar
with it in general.

But as we will soon see,

being familiar with the
destination doesn't mean

that it can't throw a few surprises.

His second-in-command
was a 34-year-old first officer

who, on this day, had
about 3,500 hours in total,

of which 618
were flown on the 727.

And the third flight crew member

was a 34-year-old flight engineer

whose experience was similar
to that of the first officer.

Now all of the pilots had been off

for more than
24 hours before this duty

and the scheduled departure time

was at a very civilized hour,

so there's no reason to believe

that fatigue played any role

in what was soon about to happen.

Now instead the crew were
likely in a quite good mood

as they completed their
normal pre-flight activities,

checking weather,
NOTAMs and flight plans,

which all looked okay.

It looked like it was going
to be a very pleasant flight

down towards the Canary Islands.

So after having boarded everyone

and completed the pre-flight set up,

the crew started up their engines

and taxied out for takeoff
from Manchester at time 9.22 am,

with the captain as pilot flying

and the first
officer as pilot monitoring.

Now the climbout and cruise phases

of this flight went off without a hitch,

but the pilots then
likely started preparing

and briefing for the approach

a bit earlier
than usual on this day.

And that was because
they had seen,

during their pre-flight briefing

that the approach
they had ahead of them

was possibly going
to be a little bit unusual.

You see, in the Canary Islands

the prevailing winds normally blew

from the Atlantic Ocean in the west,

causing most flights to approach

from the east using Runway 30

in order to land with a headwind.

But on this afternoon,
the wind was instead blowing

from the other direction, from the east,

forcing inbound aircraft to approach

the reciprocal Runway 12 instead.

Now we don't know how
many times the captain

or the other crew members

had actually used
Runway 12 in the past,

but it was likely not something
that they did very often.

And to make things even worse,
Tenerife North Airport was,

and still is, notorious for its frequent,

fast-building fog that can appear
from nowhere within minutes.

The airport sits at
2,000 feet above sea level

on a shoulder between two mountains,

and the marine fog
that forms over the ocean

frequently collides with
the western slopes of Tenerife

and then gets funneled

through the gap
directly over the airfield.

But like I mentioned before,

on this day the reported
weather at the airport

was more or less okay, with
around six kilometers of visibility

and scattered clouds at 400 feet,

broken at 800 feet,
and further scattered clouds

at 1,100 feet with some light drizzle,

not great for sunbathing,

but good enough for normal landings.

But these cloud layers also meant

that higher up on the mountainsides,

the fog was extremely thick,

so thick in fact that a
weather station located

at a close to 8,000 feet elevation

on the mountainside
reported nil visibility.

This meant that the very
high terrain south of the airport

would be completely obscured,

including the nearly
12,200-foot Teide Volcano,

which is the defining
geographical feature on Tenerife.

Because of that,
the minimum safe altitude

in the airspace south
of Tenerife North Airport

was 14,500 feet,
which is worth remembering.

Anyway, as the flight
near the Canary Islands,

the first officer made contact

with the Las Palmas
Area Control Center,

who soon cleared them
to descend down to 11,000 feet.

The first officer read this back

and the crew initiated the descent,

and after they reached that altitude,

they contacted the Tenerife
North approach controller

and reported that they were
now 14 nautical miles

away from the Tango
Foxrot November VOR beacon,

and that they were ready

to receive their approach instructions.

Before we continue here,

it's probably worth explaining
a bit more about

the different approach aids

that the crew were now going to use

as well as their procedures.

A VOR beacon, where VOR stands for:

Very High Frequency
Omnidirectional Range,

is a type of radio navigation beacon

that was very widely used
in the days before GPS

and is actually still quite common,

especially here in Europe.

These VORs emit signals
hat are modulated differently

depending on the
direction of the emission,

which allow the VOR
receivers on board aircraft

to determine the
precise magnetic bearing

from the VOR to the aircraft.

This enables the pilots
to navigate using imaginary lines

or radios defined
by a particular bearing

from the beacon.

So, for example, the 270 degree radial

from the VOR points
due west and so on.

A lot of airports have VORs installed

to help pilots locate the airport
before starting to maneuver

for the approach, and
it can also be used

to align the aircraft with
the runway as an approach aid

if an instrument landing system,
ILS, is not available.

But in this case, the
Tango Foxrot November VOR

was not actually located at the airport.

Instead it was sitting on a hilltop,

a few miles northeast of the airport

in order to maximize
its detectable range.

Located at the northeast
end of Runway 12-30,

there was a less-sophisticated
beacon called an NDB locator

with the Morse
code identifier Foxrot Papa.

A non-directional beacon, or NDB,

is a radio aid that can be tracked

using an automatic
direction finder, an ADF,

and this is a very simple
instrument which just points

in the direction that
a signal is coming from,

but it doesn't
contain any radial information,

which makes the NDB navigation less

precise than navigating using a VOR.

In this case, because the
Foxrot Papa beacon was used

to mark the entry point
to the approach procedure

for Runway 12, it was
also known as a locator

rather than just an NDB.

And in order to approach Runway 12,

a flight inbound from the
northeast like this flight was

would normally need to fly first

via the Tango Foxrot November VOR

and then turn southwest onto Radial 255

directly towards
the Foxrot Papa NDB.

After reaching the Foxrot Papa,

the aircraft should then turn
right onto an outbound heading

of 302 degrees, which
would take it out over the ocean,

before making
a teardrop course reversal

to the left back towards the airport.

And from that point, the
aircraft would be in a position

to pick up the instrument landing system,

which would then guide

the aircraft the rest of
the way down to the runway.

Now this was quite
a bit more complicated

than the more commonly
used Runway 30 approach,

which just involved flying to
an NDB called Tango X-ray,

from where the instrument landing system

could then be 
picked up immediately.

Now the reason that these procedures

had to be flown this way

was that there was no radar
available at Los Rodeos Airport,

so all approaches
had to be intercepted

using procedural arrivals.

But then again,
flying procedural approaches

would not have been
very uncommon back then,

and there was nothing in this procedure

that was particularly out of the ordinary,

except maybe that high
terrain to the southwest,

which I mentioned before.

And when we're on the
subject of things

that are out of the ordinary,

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and now where were we?

Yes.

After establishing  
contact at time 13:16,

the Tenerife North
Controller cleared the flight

to descend down to 6,000 feet

in preparation to cross
Tango Foxtrot November

and then to enter
the approach procedure.

The captain dialed in
the new cleared altitude,

the flight engineer reduced
thrust in order to descend,

and the first officer then reported

when the aircraft was
seven nautical miles away

from the Tango Fox November beacon

in order to get further instructions.

At that same time, he
also requested the local air pressure,

QNH, in order to
get the correct reference

to the altitude above the sea,

and also the QFE,
which would give him

the altitude reference
over the airfield.

Once those values
had been received and set,

they were then cross-checked

in accordance with
their standard operating procedures,

and the captain now also suggested

that the first officer should tune

the ILS frequency on
his navigational radio box,

and he also confirmed
that the outbound heading

after Foxtrot Papa
would be 302 degrees.

So at this stage,
everything was completely normal

and the crew seemed
to have a good grasp

of the procedure they
had in front of them.

But just a few miles ahead,

an island-hopping
turboprop belonging

to Spain's flag carrier,
Iberia, was also an approach

to Runway 12, and the crew
on board that aircraft

were communicating with
the controller in Spanish.

Now the pilots of Flight 1008
didn't understand Spanish,

and from their conversations,

it doesn't seem like
they paid much attention

to that aircraft at all.

Instead, they continued to
monitor their position,

relative to the Tango
Fox November VOR,

and at time 13:18:15,

the captain called out,
"Just about to go overhead."

The first officer then reminded

the captain that the procedure called

for them to leave Tango
Fox November on Radial 255.

But as it turns out,

the aircraft actually passed a
little less than a mile east

of the VOR, and after passing abeam it,

they were also slow
to make the right turn,

which meant that they never

actually intercepted that 255 radial.

Now, we can never know
for sure why this happened,

but it was most likely done on purpose.

You see, the distance

between Tango Fox November
and Foxtrot Papa was very short,

and Flight 1008 was traveling

at an airspeed of around 250 knots

when they passed abeam to the VOR.

Today, we wouldn't fly that fast

when starting a tight
procedure like this,

since our aircrafts are now very slippery

and take time to decelerate.

But older aircraft like the 727

had much less effective wings,

which meant that they could
easily keep the speeds up high

for longer, since the speed
would just rapidly bleed off

when the thrust levers were closed.

This also meant that most jets

approaching Tenerife back then,
including this one,

would normally overshoot
this first turn slightly

before correcting course
in order to be able

to intercept the 302 outbound course

from the NDB at a slightly
more comfortable angle.

There was so little time
between Tango Fox November

and Foxtrot Papa that
they probably wouldn't be able

to intercept the radial anyway.

And on top of that, if they
flew directly over Foxtrot Papa,

they would potentially overshoot
the pattern significantly,

which could take the aircraft

into the area south of the airport

where the minimum
safe altitude was 14,500 feet.

Now, this is obviously not how
this was supposed to be done.

A lower speed would have
solved all of those issues,

but sometimes, procedural
shortcuts like this can start

to creep in due to
pure convenience and time saving.

And if I was to guess, this was likely

the reason that the captain
of this flight flew a bit wide

around the Tango Fox November.

Now, due to some radio chatter

with the Hapag-Lloyd flight

that was taking off from Los Rodeos

plus some other distractions,

the flight crew didn't actually report

crossing Tango Fox November

until 33 seconds after they
had passed abeam hit.

And like I mentioned,

Tenerife North Airport
didn't have radar at the time,

so position reports like this

were the only way for the controller

to determine where
the traffic was located.

As a result, when the crew reported

that they had just
passed Tango Fox November,

the controller realized that
the 727 was traveling so fast

that it would risk getting too close

to the slower Iberia
turboprop in front of them

if he didn't do something.

So he hastily decided
to put Flight 1008

into a holding pattern

in order to ensure
sufficient traffic separation.

At time 13:18:54,

the approach controller
transmitted the following message,

"Roger, the standard
holding overhead Foxtrot Papa

is inbound heading 150,

turn to the left,
call you back shortly."

And this would end
up being the critical moment

that put the accident
sequence into motion.

So let's take a moment to analyze why.

Despite the controller's statement

that this was a standard holding,

there was actually no officially
published holding pattern

around the Foxtrot Papa beacon.

There was a published holding

around Tango Fox November,

as well as around Tango X-ray,

forming part of the go-around
procedure for Runway 12,

but Flight 1008 was not in
a position to enter any of those.

Instead, the controller essentially

invented a holding pattern
based on Foxtrot Papa,

and he did so so quickly

that this was likely not the first time

that he had used
this particular pattern.

Now, it's not wrong or illegal
to make up holding patterns.

In fact, that happens all the time,
and it's perfectly okay

as long as it doesn't cause any issues

with terrain or traffic separation.

But the issue here
was that the controller said

that this was a standard holding,

which would imply that
the holding could be found

in the published approach chart,

and therefore needed to
be verified by the pilots.

On top of that, the entry

into this suddenly-proposed
holding pattern

would not be very simple

from the position that the
aircraft was now coming from.

What the controller
wanted the aircraft to do

was to join a left-hand holding
pattern over Foxtrot Papa

with an inbound course of 150 degrees

and an outbound
course of 330 degrees.

If it was flown that way,

it would keep the airplane
over relatively low terrain.

But to do this, Flight 1008

would have to first fly
over the beacon,

then turn right onto heading of 330,

fly outbound for one minute,
perform a course reversal,

and then proceed inbound

to Foxtrot Papa again
on the requested inbound course.

Quite a complex maneuver to fly

when you're
almost over the beacon.

Now, the pilots might
have eventually figured this out

if not for a tiny slip of
the tongue by the controller,

which changed this
entire course of events.

Remember that the
controller wanted Flight 1008

to fly counter-clockwise

around the holding pattern,
making left turns?

Well, this meant that what
he wanted to say

was turns to the left,

but what he actually
ended up saying

was, "Turn to the left," which
has a very different meaning.

Turn to the left
is normally interpreted

as a command to turn left, right away,

which was not at
all what the controller

wanted them to do here.

What he attempted to say

was only a description
of the holding pattern,

which is technically just informational,

not an order, and that also made sense,

given that he didn't
have any radar available.

Spanish investigators later used this

to argue that the controller
didn't bear any responsibility

for issuing a non-standard clearance,

but given how his call actually sounded

to the pilots,
that's not completely fair.

Anyway, when the flight
crew received this message

from the controller,
they simply replied,

"Roger," with no further readback

or request for confirmation.

They might have thought at first

that they understood what he said,

but within 10 seconds,
the captain realized

that he wasn't able to picture

what the controller was asking from him,

so he said, that's an odd
sort of one, the runway.

He then interrupted himself

with a confirmation that
they had 1,000 feet

to go to their
cleared altitude of 6,000 feet,

and after that, the first officer said,

"No, I'm not, er...
Supposedit's all right?"

The captain continued with,
"I'll just turn straight round

to the left on the 150
when I go overhead then,"

to which the first
officer seemed to agree.

Now this shows that
the captain clearly believed

that he had been told
to turn left on to heading 150

after crossing Foxtrot Papa,

which again was not at
all what the controller had intended.

A command to turn to the left

was completely incompatible
with an instruction

to fly a holding
pattern inbound on 150 degrees

to Foxtrot Papa since,
like what I said earlier,

that would require a right turn
followed by a course reversal.

So in the captain's mind,

the instructions didn't make sense,

but he had been able
to pick out two elements

in the message which seemed clear to him,

150 and turn to the left.

So with Foxtrot Papa now coming up

in less than one minute,

he didn't have a lot
of time to figure it out.

In a stressful situation,

without fully comprehending
what the controller had said,

he accepted that the best thing to do

was just to execute
the part of the clearance

that he understood,

and then try to
figure out the rest later.

In hindsight, it's easy to say

that he shouldn't have acted

on an incomplete understanding
of those instructions,

but in that moment,
with the sudden time pressure

and the added workload
of the sudden holding clearance,

it would have been a lot harder

to think with that kind of clarity.

And it is also worth remembering

that this all happened
in a 727 cockpit,

with no fancy navigation
displays, only dials.

Besides, this CVR transcript suggests

that both the first officer
and the flight engineer

were looking at the charts
when this all happened,

likely searching for
that standard holding

in order to be able to verify it.

And the first officer had said,
"I suppose it's all right,"

which might have reinforced
the captain's belief

that he had understood
the clearance correctly.

Anyway, seconds later,
having made his decision

on how to fly, the captain focused

his attention on the rapid approach

of the Foxtrot Papa NDB.

He said, "The only thing is,
we're just about to miss it.

(chuckles) It's too close."

At this point, the captain
and the first officer also agreed

to tune both automatic
direction finders

to the frequency of the Foxtrot Papa,

so that they could track it more easily

during the holding pattern.

And finally, at time 13:19:46,

they passed abeam Foxtrot Papa,

slightly to the southeast,
and the captain called it out.

This prompted the
first officer to report

the waypoint passage to the controller,

and he also confirmed that they
were now taking up the hold.

But in reality, they actually
kept flying straight ahead

for another about 20 seconds,

covering around two nautical miles

before beginning the left turn.

Now, the reason for
this delay isn't really known,

but it might have been
because the pilots

were still trying to wrap their heads

around the maneuver that they
now had ahead of them.

In fact, a few seconds
before they began that left turn,

the first officer said,
"Bloody strange hold, isn't it?"

Which indicates that he
was still mentally focused

on the confusing instructions.

In response to that, the captain said,

"Yeah, it doesn't...

Isn't parallel with
the runway or anything."

Now, I just want to
stop here and drive home

what is probably one of

the most important points
of this whole video.

If something seems strange
with a clearance and you get

that pit in the stomach feeling

that something just isn't right,

always speak up and
ask for further clarification.

This goes for all walks
of life and all industries,

but especially if
you're flying an aircraft.

It's always better
to ask one time too many

than one time too few,

and I want every one of
you out there to remember that.

This, by the way, is also exactly
the kind of discussions

that I'm having regularly
on my Zoom hangouts

with my Patreon crew,

and I hope to see
you there as well next time.

Just go to patreon.com/join/mentourpilot

if you think that sounds interesting.

Anyway, at this point, what
the flight crew didn't yet know

was that by overshooting Foxtrot Papa

and then turning left
onto a heading a 150 degrees,

they were now on a track to
overfly the northern shoulder

of La Esperanza, a sub-peak

along the island's central volcanic ridge

that stretched
north from El Teide.

The terrain directly beneath
their projected flight path

actually didn't exceed 5,000 feet,

but it did lie within the sector,

where the minimum safe
altitude was 14,500 feet.

So strictly speaking,

since they weren't
flying a published procedure,

maneuvering at only 6,000 feet

would have been
prohibited in this area.

The final report would
later place some blame

on the flight crew
for flying into this area

without being aware
of the applicable MSA,

but it seems likely
that at this point,

they were still thinking that they

were flying an official procedure,

even though they couldn't
find it on their charts.

At the same time
as Flight 1008 completed

their left turn onto a heading of 150

and started flying
towards the southeast,

the approach controller called up

the Iberia Airlines flight ahead of them

and asked them to verify
when they had left 5,000 feet.

Only seconds later, the
pilot of that aircraft replied

that 5,000 feet was now free

and that they were in the middle

of a procedure turn
to intercept the ILS.

As these calls in
Spanish were happening,

the first officer on Flight Engineer

on board Flight 1008 continued
to compare ATC's instructions

with what was printed on their chart,

saying things like,
"It's that way, isn't it?"

"That's a tree, isn't it?"

And, "Yes, well, the hold is
going to be here, isn't it?"

It's likely that they
were now very skeptical

about the maneuver
that they were flying,

but we can never be 100% sure

since that wasn't formally verbalized.

Anyway, as these
discussions were taking place,

the controller now called them up

and cleared them to
descend down to 5,000 feet

since the Iberia flight
had now left that altitude.

And in response, the
flight engineer again reduced

the thrust and the
captain initiated the descent.

But as they were doing this,
the captain suddenly said,

"Hey, did he say it was 1-5-0 inbound?"

likely realizing that
his mental picture

of where the controller was sending

them didn't actually make any sense.

The first officer
had probably suspected

that from the very start
because he now replied,

"Inbound, yeah."

And in response to that,
the captain said,

"That's... I don't like that."

The first officer continued by saying,

"They want to keep
going more around, don't they?"

It's not completely clear
what he meant by that,

but it is possible that
the first officer believed

that they were supposed
to keep turning left,

making a three quarters turn onto

the outbound leg
of the holding pattern,

after which they would come back

to Foxtrot Papa on
the inbound heading of 150.

If that was the case,
it would mean that

even the first
officer had indeed interpreted

the call from the controller
as an instruction to turn left.

And that would also explain why he

hadn't spoken up when the turn started.

When I read this part of the report,

I could really feel that
cold feeling in my stomach.

You know, that feeling that you get

when you realize
that something is really wrong,

but you still can't
figure out what or how.

But we don't know if the pilots

had yet realized just how dangerous

their current flight path was.

But the captain's statement of,

"I don't like that," definitely
showed some real concern.

Again, make sure you
always know what clearance

you have been given,
and if in doubt, ask.

Anyway, before the pilots could
spend much more time trying

to work out what was wrong,

the ground proximity warning system

suddenly activated at time 13:20:50.

The Boeing 727 was equipped

with a first generation GPWS,

which was state of the art at the time,

but also much less capable

than the enhanced ground
proximity warning systems

that we have on board today's aircraft.

Modern EGPWSs compares the position

and projected path of the airplane

to a digital terrain database.

But the original GPSs could only look

at the terrain directly
beneath the aircraft

using its radio altimeter.

If the closure rate with
the terrain was too high,

it would an issue sink rate
or pull up warnings.

But if the terrain ahead
of the aircraft was rising steeply,

the system wouldn't know that,

so these warnings could
still come too late.

In this case, the airplane

was now passing over
the northern shoulder

of the central volcanic
ridge while in descent,

and that resulted in a
rate of terrain closure

greater than 6,000 feet per minute,

triggering the warning envelope.

But the maximum height
of the ridge ahead of them

was actually less than
their current altitude.

So in their present trajectory,

they were not in any
danger of striking the terrain.

But, of course, the
pilots who had now lost

their position situational awareness

and were still flying
inside of the clouds

had no way of knowing this.

So in response to the GPWS warning,

the captain immediately announced,

"Okay, overshoot," which is an
old British term for go around.

As the flight engineer advanced

the thrust levers to
the takeoff go around thrust,

the captain also halted their left turn

and added, "He's taking us
around to the high ground,"

and after stating that,
he continued rolling right

onto a steeper and
steeper right-hand turn.

But what he didn't do was

to raise the nose in
order to initiate the climb.

And why was that then?

Well, during GPWS response training,

we pilots today are required

to practice a terrain escape
maneuver in the simulator,

which includes disconnecting
the automatic setting,

full thrust pitching up to 20 degrees,

making sure the speed
brake lever is down,

making proper
call outs and so on.

This maneuver is drilled
into everyone flying today

in order to make sure that the response

to a hard GPWS warning

is immediately executed from
memory and without questions.

As it turns out, the captain
and the flight engineer

had also undergone some type

of GPWS training back in 1978,

and Dan-Air did have a
procedure for GPWS response,

but back in those days
GPWS was a very new technology

and there is a possibility

that training had
been only theoretical.

So we don't know exactly what was going

through the captain's head,
but based on his statement

that, "He's taking us
around to the high ground,"

he probably believed
that the controller's instruction

to turn left was faulty

and that the controller had told him

to turn towards an unsafe direction.

Believing that the
GPWS warning occurred

because they were turning
left towards high terrain,

the captain may have reasoned

that the best way
to escape the situation

was to turn to the right instead.

So without having
practiced the maneuver

in the simulator, the
captain's immediate reaction

was to turn rather than to climb,

which sadly would seal their fate.

Because as the right turn now continued,

the aircraft passed over

the top of the ridge
and then over a valley,

causing the radio altitude to increase,

which silenced the GPWS warning,

10 seconds after it had started.

The captain commented,
"Watch my eepers,"

referring to the engine
pressure ratio or EPR,

essentially ensuring
that the flight engineer

maintained TO/GA thrust and
didn't over-boost the engines.

But it also now seems like

the first officer wasn't convinced

that they were now taking
the right course of action.

So he called out,

"I suggest a heading of 1-2-2 actually

and take us through the overshoot."

A heading of 1-2-2 degrees
was the heading prescribed

by the official Runway 12
missed approach procedure,

which would take them
east over the ocean,

so this was a pretty sensible suggestion.

But 1-2-2 degrees was also

to the left of their current heading,

which contradicted
the captain's assumption

that their left turn was
what had caused the GPWS warning.

As a result, he just continued
turning right past due south

and then all the way
around to the southwest,

directly towards the 5,700 foot
high summit of La Esperanza.

Tragically, they might
still have cleared the summit

if they had just maintained altitude

or climbed following
the terrain escape maneuver.

But due to the high bank angle
they were now using,

the plane actually lost
lift during the maneuver,

causing a slight descent instead.

Still flying over the valley,
the flight engineer expressed

his nervousness by commenting,
"Let's get out of here."

But the captain simply repeated,

"He's taking us around
to the high ground."

Moments later, without any
new GPWS warnings,

and believing that he
had corrected the situation,

the captain
called up air traffic control

and reported, "Dan-Air 1008,

we've had a ground proximity warning."

This was then followed

by the flight engineer calling
out twice that their bank angle

was now above the recommended
maximum of 30 degrees.

And his words were
the last ones captured

on the cockpit voice recorder.

With the mountains shrouded in
clouds, the pilots never saw

the danger coming towards them,

and the GPWS never had time

to react to the closure
rate of the steep mountain ahead.

So at time 13:21:18 Dan-Air
Flight 1008 crashed

into the forested
mountainside of La Esperanza

at a speed of 260 knots,

just 38 meters below
the top of the ridge.

Most of the aircraft
disintegrated immediately,

killing everyone on board,

and a large portion
of the aft cabin

was then thrown another
250 meters forward

over the top of the ridge and
then down to the other side.

Down at the airport,
the controller now tried repeatedly

to contact the aircraft
in order to follow up

on their reported GPWS warning,

but when he didn't get any reply,

he soon activated the accident alarm.

The problem was though that

with no radar available
at Tenerife North,

rescuers had no idea
where the aircraft was located,

especially since it had taken a turn

that the controller had
not intended them to take.

This meant that the
wreckage wasn't discovered

until seven hours after the crash,

when a couple of
motorists on the road

to El Teide National Park
saw some debris on the road

and correlated that to the radio report

of a missing aircraft.

This crash was, and actually
still is, the worst loss of life

on board a British airliner ever,

so the investigation received
considerable public attention

especially when the Spanish

and British investigators didn't agree

on how to weigh
the causes of the accident.

The Spanish investigators wrote

that the pilots
were ultimately responsible

for being aware of their position
in a non-radar environment,

and that it was their obligation

to climb to a safe altitude

as soon as they became unsure
of where they actually were.

They also cited the pilot's
failure to request clarification

when they didn't understand

the controller's initial transmission

as a major cause of the accident,

as well as their incorrect
response to the GPWS warning.

They pointed out that if
the pilots had done nothing at all

when the GPWS activated,

they would have passed
safely over the ridge

and continued out over the sea.

So the Spanish investigators argued

that it was the captain's
decision to turn right

that took them back
around to the high terrain

and ultimately led to the crash.

But the British
investigation team believed

that the controller's use
of an unpublished holding pattern,

one that didn't appear
on the pilot's chart,

as well as its verbal slip-up
saying turn instead of turns,

played a very important role

in the pilots' loss
of situational awareness.

They also noted that
if the holding pattern

had been designed according
to international standards,

the minimum altitude in the hold
would have been 6,000 feet,

which would have
incidentally prevented the crash.

But regardless of who made
the most serious errors here,

the disaster was made possible

by the poor infrastructure
at Tenerife North Airport,

including the lack of radar

and the poorly-designed
approach procedures.

It's also important to remember

that the technology available in 1980

was far less capable than
what we now have available,

and it's exactly because
of accidents like this

that we today have
these vastly improved systems

and that we pilots are
so well trained in using them.

This accident led to recommendations

to always question any clearances
that weren't 100% clear

as well as some
other recommendations as well.

But in the long run,
this accident also led

to better training
around GPWS maneuvers

and therefore, a
significant increase in safety.

Our current fantastic
safety record proves

that accidents like these
today are largely preventable,

but they are only preventable

because of stories like this

and that's why I keep telling them.

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