Original subtitles

Narrator: Tragic accident or calculated murder?

Man: Now let's see the elevations.

Narrator: Investigators reopen a 55-year-old mystery.

Man: This was a major world event.

Man: We're going down. Brace! Brace!

Narrator: What caused a crash

that killed the U.N. Secretary general?

Man: It was devastating.

Man: This gentleman was a champion of world peace.

Narrator: How did a top-secret peace mission in Africa

end in death?

Man: It's tough to see how they could have screwed this up.

Man: Certain people believe it's just not possible

that Dag Hammarskjold was killed in a common accident.

It had to be something more.

Narrator: Controversial theories abound.

Man: Dag Hammarskjold was murdered. Period.

Narrator: But the truth may finally be within reach.

Man: As an investigator, I don't want to close any doors.

Flight attendant: Ladies and gentlemen, we are starting our approach.

Pilot: We lost both engines!

Flight attendant: Put the mask over your nose.

Emergency descent.

Pilot: Mayday, mayday.

Flight attendant: Brace for impact!

Controller: I think I lost one.

Man: Investigation starting into this tragedy...

Man: He's gonna crash!

Narrator: Swedish air crash investigator Sven Hammarberg

is entering a world of intrigue

and deadly cold war conspiracies.

A special commission reporting to the U.N.

Needs him to determine

whether a 1961 air disaster was an accident or an assassination.

Sven Hammarberg: The commission knew that I had some experience

in that field of old aircraft accidents,

so they called me.

Narrator: The pressure is on to get to the bottom

of an aviation mystery that's as controversial today

as it was 55 years ago.

Henning Melber: There's a wide range of things

that have never, ever been adequately considered.

They might not bring the ultimate truth,

but it requires to look carefully again.

Narrator: Hammarberg studies the events

from the night of the fateful flight.

A united nations transport plane, the Albertina,

is on a vital mission in central Africa.

Pilot: Estimate Abeam Ndola at 2347,

arrival time 00:20.

Narrator: The destination is Ndola airport

in the British colony of northern Rhodesia.

Controller: Roger.

Ndola weather, wind 1-2-0 at seven knots,

visibility five to ten miles with a slight smoke haze.

Narrator: Controllers and local dignitaries anxiously await

the arrival of one of the most important people in the world.

Controller: Set altimeter to 30.15.

Pilot: Roger.

Request descent clearance at 5-7.

Controller: Roger at 5-7.

Cleared to descend to 6,000 feet.

Narrator: On board the dc-6

is U.N. Secretary general Dag Hammarskjold.

Dag Hammarskjold: At least they're willing to talk.

What else do we know about their latest demands?

Narrator: He's flying in from the Congo

to hold high-level peace talks with a rebel leader.

Melber: Hammarskjold,

and most likely members of his entourage on board,

were pretty aware that this is a difficult mission.

It was a secretary general for whom a physical risk

was an integral part of his job.

Pilot: Alright.

Descending to 6,000.

Nil traffic ahead.

Co-pilot: 6,000. Yes, sir.

Narrator: The captain is 35-year-old per Hallonquist.

Co-pilot: Our visibility should be pretty good

once we get down there.

Narrator: 29-year-old lars Litton

is Hallonquist's first officer.

Robert Macintosh: The life of flying a transport airplane

in the Congo during the 1960s,

during the decolonization era,

was indeed a fantastic challenge for everyone.

Narrator: Former pilot and NTSB investigator Robert Macintosh

flew transport missions for the U.N. Throughout the '60s.

Macintosh: During my time in the Congo,

I was probably a lucky guy

because there were mercenaries around,

and I never found any bullet holes

in the aircraft that I was flying.

Lars Litton: 7,000.

Per Hallonquist: Alright.

Give me 2,000 rpm and 20 inches.

Litton: Minimum descent altitude?

Hallonquist: That's 5,000 feet,

but we'll have the runway in sight long before then.

Narrator: The flight left the Congolese capital,

Leopoldville,

a little more than six hours ago.

For security reasons, it's flown an indirect route to Ndola.

Melber: They made arrangements in the route of the plane

to avoid any unpleasant surprises.

Hammarskjold: Number one, we need to extend the ceasefire.

We can't be seen as being the enemy here.

Narrator: To prevent an ambush, no flight plan has been filed,

and the pilots have maintained radio silence

for most of the flight.

The mission is a closely guarded secret.

Controller: Are you proceeding to Salisbury after Ndola?

Hallonquist: Negative.

Narrator: Even at this late stage,

the crew needs to be secretive about the mission.

Controller: Are you staying in Ndola?

Narrator: They don't know who might be listening in.

Hallonquist: Negative.

Controller: Due to parking difficulties,

we'd like to know your intentions.

Hallonquist: We will give them on the ground.

Controller: Roger.

Macintosh: The security of the airport

and of the flying environment

was sometimes in question.

There were, there were opportunities for counter forces

to perhaps shoot at aircraft that were on final approach.

Hallonquist: Pre-descent checklist, please.

Litton: Anti-collision lights?

Hallonquist: On.

Litton: Cylinder head check?

Okay.

Speed to 1-8-0 knots.

Man: Go ask the pilots how much longer till we land.

Narrator: The secretary general and his delegation

should be on the ground in about ten minutes.

Hallonquist: Your lights in sight.

Overhead Ndola.

Descending.

Controller: Roger. Report reaching 6,000 feet.

Hallonquist: Roger.

Controller: Okay. They're 10 minutes away.

Narrator: Because of the unusual flight path,

the plane now needs to fly past Ndola airport

and circle back to touch down on its only runway.

Macintosh: Ndola was a bit, we say, out in the sticks,

with a little control tower and with some surrounding hills.

And certainly at night it was extremely difficult

to make approaches there.

Litton: 180 knots, sir.

Hallonquist: Speed is good. Thank you.

Macintosh: You certainly have to be extremely vigilant

to the hazards around such a small airport.

Narrator: The crew begins the final swooping left-hand turn

that will line them up with the runway below.

The mission to Ndola is about to begin--

a mission that could change the fate of nations.

Newscaster: The united nations security council meeting again

to deal with the difficult and dangerous Congo situation.

It was resolved to call upon Belgium

to withdraw her troops from...

Melber: The Congo in the early '60s

was of utmost priority in the cold war.

It was of top geostrategic importance.

Narrator: The Congo recently won its independence from Belgium.

But the new nation's southern region of Katanga

has declared itself an independent state.

A bloody civil war has erupted.

And with the world's richest uranium mine in Katanga,

world powers, including the U.S. And the Soviet Union,

are backing opposing factions.

The risk of a global catastrophe is very real.

Melber: One needs to recall that the nuclear bombs

that were thrown on Hiroshima and Nagasaki

were supplied with uranium from Katanga.

Narrator: Hammarskjold hopes to resolve the deadly conflict

and help reunite the Congo.

But on the ground in Ndola,

controllers are growing concerned.

Controller: Albertina, Ndola tower.

Do you read?

Narrator: The secretary general's plane is overdue.

Macintosh: Where did the aircraft go?

Why, why have we not seen it?

Controller: Albertina, Ndola tower.

Please acknowledge.

Macintosh: "Where are you?

Why am I not hearing from you?"

That would have been very present

in the minds of the controller at that point in time.

Narrator: The controller contacts other airports

in the region.

Controller: Salisbury, Ndola airport.

Have you had any word from the U.N. Albertina?

Controller: Nothing at all.

Narrator: Perhaps the Albertina's secret mission

has taken it to a different destination at the last minute.

Controller: Lusaka, Ndola airport.

Have you had any contact with the U.N. Flight?

Controller: Negative. No contact here.

Narrator: The plane carrying

one of the most important men on the planet is missing.

It's a mystery that will haunt Ndola and the world

for decades to come.

By dawn,

news of the U.N. Secretary general's disappearance

is spreading fast.

Clyde Sanger: We heard that he was missing,

so what were we to do?

We weren't going to sit around Ndola.

Narrator: Clyde Sanger covered Hammarskjold's mission in Africa

for the guardian newspaper.

Sanger: A number of journalists got together

and chartered a plane and flew over the area

and spotted where the plane had come down.

Narrator: On the side of a hill nine miles west of the airport,

journalists spot a gash in the trees.

Sanger: And it was quite broad.

It had cut through a lot of trees,

and it was an open space like that, with stumps of trees.

Narrator: Whatever went wrong in the skies above,

the flight clearly ended with a violent impact...

Followed by intense fire.

When local authorities arrive,

they find bodies surrounded by badly scorched wreckage.

Sanger: Northern Rhodesian police said,

"No, stay back, stay back,"

and so we had only a distant view.

They had found quite a large fuselage in one place,

which we could see,

and we were told afterwards

that Dag Hammarskjold was killed.

Newscaster: For over eight years,

Dag Hammarskjold spoke for and personified

the united nations organization.

An economist from Sweden,

he took over from secretary general...

Macintosh: The secretary general had been a very famous guy,

a champion of world peace,

so this was a major world event.

John F. Kennedy: I know that I'm speaking

for all of my fellow Americans,

expressing our deep sense of shock and loss

in the untimely death

of the secretary general of the united nations,

Mr. Dag Hammarskjold.

Narrator: With the loss of Dag Hammarskjold and his delegation,

prospects for peace in the Congo fade.

Regional power brokers have no interest

in following through on the secretary general's mission.

Macintosh: His mission to continue to attempt to reunite

the province that he was concerned with,

Katanga province,

was counter to the interests of a lot of people.

Melber: I think it's pretty obvious

that there were a plethora of interests out there

who were not really mourning the death of Hammarskjold.

Narrator: The cold war politics surrounding the flight to Ndola

lead many to speculate

that the secretary general's plane was shot down.

Melber: Was there anyone who wanted to see Hammarskjold dead?

Where do you want me to start and where to end?

Narrator: The world may soon learn more about the crash

from a surprising source.

Incredibly, there is a sole survivor.

Against all odds,

a 36-year-old U.N. Security officer

lived through the heavy impact and raging fire.

Harold Julian is in critical condition.

But if he can recover and tell his story,

he might provide valuable evidence.

While they wait to hear what Julian will say,

Rhodesian government investigators begin searching

for clues in the wreckage.

They face a daunting task.

About 80% of the fuselage is completely melted.

Macintosh: Every air safety investigator

has a given set of things that he's really looking for.

He wants to find out if the whole airplane is there.

Is there something missing?

He's looking for the tail, he's looking for the wingtips,

he's looking for the power plants, et cetera.

All those basic things are elemental.

Investigator: That's it, guys.

Slow and meticulous.

Narrator: Amidst the burned wreckage

there are also personal effects...

Poignant reminders of lives cut short.

Even these can help investigators learn more.

Wrist watches damaged by the sudden impact

reveal the exact time of the crash.

Investigator: 12:13.

Narrator: The secretary general's plane hit the ground

three minutes after its last radio transmission.

Macintosh: What happened in those three minutes?

Where were they in those three minutes?

Do we have witnesses?

Do we have a direction?

What can we tell happened there?

And indeed was there a possibility of some interdiction

from an outside force?

Perhaps ground fire,

somebody trying to shoot down the airplane,

or from the air.

Hallonquist: Your lights in sight.

Overhead Ndola. Descending.

Narrator: Critical questions about the flight's final moments

will not be answered by a voice or data recorder.

The dc-6 was not equipped with either.

The only chance of getting a firsthand account

about what happened

rests with the badly injured U.N. Security officer.

Harold Julian: Dag said...

Go back.

Narrator: Harold Julian's few brief words are astounding.

Julian: It blew up.

Narrator: He suggests

that the plane blew up before it crashed.

Hammarskjold: We need to go back!

♪

Julian: Then there was the crash.

Hammarberg: He was not in good shape

after the accident.

He had heavy medicine and so on,

so, um, it's hard to,

to measure the value of his statement.

Narrator: Investigators hope Julian will provide more details

after he recovers,

but he never does.

He dies five days after the accident.

Investigator: Did it really blow up before the crash,

like he says?

Narrator: Could a missile or bomb have taken down

the secretary general's plane?

The separatist rebels do have a fighter jet

capable of shooting down a dc-6.

A french-made Fouga Magister has been attacking planes

in the region.

Hammarberg: The Fouga could have been waiting for the dc-6.

They could have used force.

Narrator: Investigators study the pilot's handbook

for the Fouga.

They discover that the fighter's maximum combat range

is 419 kilometers, or 260 miles.

It's a key finding, because the nearest fighter base

is almost 260 miles away.

Investigator: There's no way a fighter jet

took off from this base,

shot down a plane here,

and then made it back to the base safely.

Macintosh: The possibility of a Fouga fighter

in the middle of the night finding this aircraft,

shooting it down, returning to its base...

It didn't fit the conditions that were there

on that given night.

Narrator: Investigators study the metal skin of the dc-6,

looking for any evidence that it was ripped open

by machine gun fire or a missile.

They find none.

Going a step further,

they test ash from the crash site

for the presence of explosives.

Hammarberg: They tried to look for it.

They, they divided the metal parts

and small pieces and so on,

and they didn't find anything in that way.

Narrator: What's more,

when investigators study key pieces of wreckage

from the dc-6,

everything points to a plane

that was coming in for a routine landing.

Investigator: Gear down, flaps out.

These guys were getting ready to land.

Hallonquist: Flaps 30.

Litton: Flaps 30.

Macintosh: The landing gear was down.

The flaps were extended.

Hallonquist: Okay. Speed down to 120 knots.

Macintosh: If there had been an attack,

they would have wanted to get the heck out of there,

and consequently, the evidence just doesn't speak of an attack

from ground or air.

Narrator: Despite all the rumors,

Rhodesian investigators can find nothing pointing to foul play.

The cause of the crash that killed 16 people

on a secret U.N. Mission remains a mystery.

Hallonquist: Going down! We're going down!

Brace! Brace!

Narrator: 11 days after the accident in Ndola,

dignitaries from around the world

gather in Dag Hammarskjold's hometown of Uppsala

for a state funeral.

The wreath placed by his family contains a single word:

Why?

Melber: It was devastating.

Hammarskjold was a person of utmost integrity.

He believed in justice.

He believed in equality.

He believed in solidarity.

Narrator: Digging into the Albertina's maintenance records,

investigators make a disturbing find.

Investigator: "Bullet hole in engine number two."

That's not something you see every day.

Narrator: Just hours before the dc-6 took off for Ndola,

the plane was hit by gunfire.

Macintosh: There were issues with groups

that would fire at aircraft on the ground,

trying to disrupt things.

Narrator: Mechanics repaired damage to an engine,

and the plane was deemed fit to fly.

The discovery leads investigators to wonder.

Investigator: So, just how badly damaged was that engine?

Hallonquist: We lost engine number two.

I need max power, number one.

Litton: Max on one.

Narrator: Perhaps the damaged engine failed

at a critical moment,

causing the Albertina to suddenly lose altitude.

If the theory is right,

investigators should be able to confirm it

by taking a close look at the propeller blades.

Macintosh: We have to check each and every one,

see if there was indications of bending

on those propeller blades

as they, as they entered the forest.

Investigator: These things must have been spinning mighty fast

to chew up this amount of wood.

Narrator: The damage to the blades leaves no doubt.

They were spinning normally when they hit the trees.

Macintosh: They were all quite symmetrical

and indicative of power plants

that were fully operational as the, as the crash took place.

Investigator: Well, it can't be engine failure.

Narrator: The bullet damage to the engine

did not cause the crash.

Investigator: According to the chart,

they should have been 6,000 feet here.

Narrator: Next, investigators study the navigational chart

for Ndola.

Investigator: The top of the hill is 4,300 feet.

Narrator: They calculate the altitude

the Albertina should have been flying at

when it crashed.

Investigator: Add 70 feet for the trees.

That means he should have been nearly 1,700 feet

above the treetops.

Narrator: At the crash site, damage to the trees shows

that the plane traveled forward for more than 750 feet

before coming to a stop.

That distance means the plane hit the treetops

at a shallow angle,

while descending gradually.

Hammarberg: The plane went down in the trees

in, in a gentle angle just like before landing.

Hallonquist: Okay. I'll control.

You look for the lights.

Litton: Roger.

Narrator: Investigators wonder,

when did things start to go wrong for the crew?

How did the Albertina get too low?

Investigator: The transcript says,

"Your lights in sight, overhead Ndola.

Descending.

Roger. Report reaching 6,000."

Narrator: The radio conversation

between the pilots and the controller

clearly shows that the crew

had the airport in sight from a safe altitude

less than ten minutes before hitting the ground.

Hallonquist: Your lights in sight.

Overhead Ndola.

Investigator: So we know he's right here

when he spots the airport, at around 6,000 feet.

Narrator: But the transcript reveals something more--

a single, unexpected word.

Hallonquist: Descending.

Narrator: The Albertina was already descending

when it flew past the airport.

It's a crucial lead.

Investigator: He's continuing to shed altitude here

and keeps descending

until he hits the hill here

at an altitude of 4,290 feet.

Narrator: For some reason,

the pilots began their descent much too early.

Macintosh: It's unfathomable that there was any intention

to be below 5,000 feet at that point in the, in the approach.

Narrator: Investigators are at a loss to explain

how the pilots ended up

misjudging their altitude so badly.

Investigator: Something threw them off.

What?

Narrator: They consider the possibility that the crew

was misled by an incorrect altimeter reading.

Hallonquist: Estimate Abeam Ndola at 2347.

Arrival time 00:20.

Narrator: Half an hour before he expects to land,

Hallonquist makes contact with the tower in Ndola.

Controller: Roger.

Narrator: Controllers give him

an important piece of information.

Controller: Set altimeter to 30.15.

Hallonquist: Roger.

Narrator: Pilots need to calibrate their altimeters

for every airport they land at,

factoring in the runway's height above sea level.

Macintosh: The settings of the barometric pressure

around the airfield were provided by the tower,

and that needed to be translated from millibars to inches

and placed in the window,

the little adjustment window of the altimeters.

Narrator: They examine the instruments,

looking for any sign that the crew dialed in

the wrong altimeter setting for Ndola.

A set of numbers showing barometric pressure

provides an answer.

Hammarberg: The investigators checked the three altimeters

in the plane.

They found that the altimeters were working at the time

and correctly set.

Narrator: There was nothing wrong with the altimeters.

It's another dead end.

Investigator: What do we focus on next?

Narrator: While crash investigators

continue to search for answers,

medical examiners make an astonishing discovery.

It looks like some of the passengers

suffered gunshot wounds.

Hammarberg: Finding bodies in the wreckage with bullet wounds

is of course very interesting to look into.

Narrator: Perhaps there's a sinister cause

to this accident after all.

Investigators sift through dirt from the crash site

where a critical U.N. Peace mission

ended in flames.

They find more evidence of gunfire--

shell casings and a total of 342 bullets

recovered from the bodies of the victims or nearby.

Were they fired on board the plane or from outside?

Investigators need to know.

Ballistics experts work to find the answer.

When a bullet passes through the barrel of a gun, it spins.

The spinning action marks the bullet

with telltale marks called rifling.

But ballistic testing reveals yet another surprise.

None of the bullets have any signs of rifling.

They were never fired from any gun.

Investigator: We tested every one?

Hammarberg: The persons who were wounded by the bullets

also carried bullets,

because they were, like, guards,

so they had ammunition on them.

The investigation shows that the most likely cause of the wounds

is that the bullets somehow exploded

and went into the bodies.

Narrator: Rhodesian investigators conclude

the bullets likely exploded in the heat of the post-crash fire

and were propelled into nearby bodies.

Without any evidence of sabotage or attack,

nor any sign of a mechanical failure,

the cause of the crash is looking more and more

like pilot error.

Investigator: These guys are experienced.

It's tough to see how they could have screwed this up.

Narrator: Could the crew have somehow been distracted

in the final moments of flight?

A discovery on day one of the investigation

lends support to that idea.

When rescuers searched the wreckage,

they found evidence that a U.N. Bodyguard was in the cockpit

at the time of the crash.

Investigator: So, this is the cockpit area,

and they found the security officer's body here.

Julian: Go ask the pilots how much longer till we land.

Narrator: A visitor in the cockpit

can be dangerously distracting for a crew...

Especially when they're close to the ground.

Hallonquist: We'll be on the ground in three minutes.

It's a few minutes early.

Flaps 30.

Litton: Flaps 30.

Hammarberg: You have to pay attention to small movements

on, on the instruments.

Hallonquist: You can have your guys standing by if you want.

Macintosh: Your attention to detail, to the altitude,

your altitude awareness, needs to be extremely high.

Hallonquist: I'll stop short of the terminal.

You can have the secretary general disembark there.

Hammarberg: The margins are very small.

It's a matter of seconds before they hit the ground.

Hallonquist: We're going down! Brace! Brace!

Narrator: For the Rhodesian investigators,

the evidence is clear.

The pilots simply lost track of their altitude

and flew their plane into the ground.

No sabotage, no missiles, no murder.

Hammarberg: They go into the, the questions

about sabotage and attacks,

but they conclude that the most probable cause to the accident

is some kind of pilot error.

Narrator: Those who believe this was an assassination

aren't swayed by the official findings.

Melber: It's a big thing

when a secretary general of the united nations

dies in an airplane crash.

A very big thing.

Macintosh: Certain people believe it's just not possible

that Dag Hammarskjold was killed in a, in a common accident.

It had to be something more.

Narrator: But three subsequent reports on the crash all agree.

There's no evidence of an assassination.

The Hammarskjold file is closed.

Then, in 2011,

50 years after the crash,

stunning new claims come to light.

Author Susan Williams interviews Charles Southall,

a former U.S. Intelligence officer

with an astounding story.

Southall was working

in a signals monitoring base in Cyprus

the night Hammarskjold's plane went down.

Pilot: I see the transport plane coming low.

Narrator: He claims he heard a remarkable recording.

Pilot: I'm going down to make a run on it.

Narrator: What could be the voice of a pilot

launching an attack on the Albertina.

Pilot: Yes. It's the Trans air dc-6.

Hammarberg: There is a possibility that there was

a listening station recording the radio transmissions

and sending them to the NSA.

Pilot: I've hit it.

There are flames. It's crashing.

Narrator: Is this proof of what really happened?

Evidence of a cold-blooded assassination

of the U.N. Secretary general?

There's more to the NSA officer's intriguing story

about the mysterious radio call on the night of the crash.

Pilot: Going down to make a run on it.

Narrator: He says the voice on the recording that night

was not unknown.

It was identified as a notorious Belgian pilot,

a mercenary who flew Magister fighter planes

for the rebel Katanga air force.

Paul Abram: The night that the plane was actually shot down,

I was working a night shift.

Narrator: Paul Abram was also with the NSA at the time,

stationed on the island of Crete.

He claims he heard a similar radio call.

Abram: NSA was telling us on a daily basis,

these are the places

that Hammarskjold will probably travel.

These are the frequencies

that the ground stations would be using.

Here is the tail number of his plane.

The idea being that they wanted to know how close he was

to signing a peace agreement

and for us to know exactly where he was going

and what he was doing.

Pilot: I'm going down to make a run on it.

Abram: On September 18, 1961,

the most important chatter came down to,

"We have the plane in sight. Yes, we've checked.

It's the plane."

Pilot: I've hit it.

Abram: "It's going down."

Narrator: The shoot-down theory is given added weight

when Williams reviews witness statements

that the original investigation discounted as unreliable.

They describe a second plane approaching

the secretary general's dc-6 at great speed,

guns firing.

Abram: Dag Hammarskjold was murdered. Period.

He was shot down.

Narrator: Williams lays out her shocking theory

in an eye-opening book called "Who killed Hammarskjold?"

Melber: The book itself, I think wisely so,

stopped short of a definite conclusion.

All the book wanted to achieve, and it managed to achieve,

is to say there are a lot of questions

which are not yet sufficiently answered.

Narrator: The book's stunning claims lead to action.

In 2013, Sven Hammarberg joins a new search for the truth,

gathering evidence to be presented to the united nations.

Hammarberg: My task was to look into the details

and see if there were any new information available,

and I was asked to evaluate the investigations

that had been performed before.

Narrator: He's part of a special commission of inquiry.

It includes a group of distinguished judges

who travel to Ndola to meet witnesses

from the night of the crash.

Many repeat their claim

that they saw two planes in the air over Ndola.

Melber: I think most importantly

there are still eyewitnesses,

and many of them seem to be very credible eyewitnesses,

who were just ignored.

Narrator: Could the death of the U.N. Secretary general

really be an assassination?

Hammarberg digs deeper,

trying to answer that question once and for all.

Hammarberg: When I look into the basic facts around the crash,

I look at the trees and the crash site

and the statements over radio and so on...

Okay.

Now let's see the elevations.

Narrator: He studies the terrain around Ndola airport.

He notes the height of the hills.

He compares what he finds to what's shown on the chart

used by the U.N. Pilots.

And he makes a shocking discovery.

Hammarberg: There's a hill here, a hill here, a hill here,

but there's nothing marked here.

Here, where the crash site is.

The Ndola chart does not show any obstacle or higher ground

west of the field.

Narrator: The local terrain includes hills west of Ndola

that rise to over 4,300 feet,

but they're missing from the chart.

Hammarberg: This hill could have blocked his view of the runway.

The crew might have been unaware of the height west of the field

since there were no signs of it on the chart.

Narrator: Hammarberg also discovers

that members of the crew flying the secretary general

to high-level peace talks

had been on duty for 17 of the past 24 hours.

Hammarberg: That's a long day for these guys.

Fatigue is an important factor here.

The flight had lasted for six and a half hours,

and there are signs that some of the crew were quite exhausted

even before the flight.

Hallonquist: Alright.

Descending to 6,000, nil traffic ahead.

Litton: 6,000. Yes, sir.

Narrator: For Hammarberg, the clues are beginning to add up.

He feels close to solving a 50-year-old aviation mystery

that has generated heated controversy the world over.

After carefully reviewing all the evidence

surrounding the crash of the Albertina in 1961,

Sven Hammarberg believes he now knows what went wrong

in the final three minutes of flight.

And it has nothing to do with murder.

Hallonquist: Overhead, Ndola.

Descending.

Hammarberg: Reaching the airfield and see the lights

when you have been flying for six and a half hours,

I think it's very easy for a pilot to get thinking that,

"oh, we are here. We are just going to land."

Narrator: Passing the airport, the pilots descend below

the minimum safe altitude of 5,000 feet.

Litton: 4,500.

Narrator: As they turn back towards the runway,

they suddenly lose sight of the runway lights.

Hallonquist: What the hell?

Hammarberg: You go into the dark,

and then you completely miss your references,

and that is a dangerous situation.

Hallonquist: I don't have the runway in sight.

Narrator: The pilots don't realize

that a hill is blocking their view,

because the hill isn't on their chart.

Hammarberg: Losing the visual sight of the airport

would cause the pilots to look even further

and lose more altitude.

Narrator: Before they even know they're in danger,

it's too late.

Hallonquist: Going down!

We're going down! Brace! Brace!

Narrator: A fatigued crew descending too soon

over hilly terrain that wasn't marked on their chart.

Those factors combined to cause the fatal crash.

Hammarberg: I think that all the ingredients

of controlled flight into terrain, they are there.

Macintosh: We still have that issue in aviation today.

Even with all the preclusive education

and equipment that we have,

there are still cases

where we have a controlled flight into terrain.

Narrator: To finally put the issue to rest,

there's one last piece of evidence

that investigators want to see--

NSA records from the night of the crash.

Melber: They asked the NSA to release these documents,

and the answer was that they remain classified as top secret

and will not be released.

Abram: Given my knowledge of the recordings, tape logs,

facsimiles, et cetera, that they have concerning this incident,

I'm not the least surprised they haven't been released.

Pilot: I've hit it.

Abram: Uh, it's just in their nature.

Narrator: It's been more than 50 years

since the mysterious crash in Ndola.

Without the NSA documents,

doubts about the crash still linger,

but efforts to uncover the truth continue.

Melber: For me, personally,

the biggest reason that justifies all these efforts,

that there are still family members, relatives,

close colleagues

who still live with the doubt.

Narrator: Though Hammarskjold died

before he could stop the fighting in Katanga,

many believe his efforts prevented the conflict

from raging out of control.

Melber: If it wouldn't have been

for Hammarskjold's intervention in the Congo,

it could have easily escalated into a third world war.

Narrator: Just a few months after his death,

Dag Hammarskjold became the first person

to be honored posthumously with the Nobel peace prize.

Melber: We should remember Dag Hammarskjold and the others

as human beings who were willing to risk their lives

on a dangerous mission

to contribute to more peace on our earth.