March 31, 2023 • 34 mins
Air traffic controllers are meant to stop aircrafts from flying into one another... and if they fail, computer systems are installed to warn pilots of a coming collision. But sometimes these humans and computers give conflicting and confusing advice. Who to believe?
When a cargo plane and a Russian airliner collided in just such a situation, the authorities scrambled to work out how to prevent a repeat of the disaster... but a grieving father decided to seek revenge on those he held responsible.
For a full list of sources for this episode, go to timharford.com.
See omnystudio.com/listener for privacy information.
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:15):
Pushkin. Japanese Airlines flight nine oh seven is flying from
Tokyo to Okinawa. It took off twenty minutes ago, and
it's almost completed its climb to its cruising altitude, close
enough that the fastened seatbelt sign has been switched off
(00:38):
and the cabin attendants are serving hot tea. The year
is two thousand and one. The airspace around Tokyo is busy.
Another Japanese Airlines plane, flight nine five eight, is coming
in from South Korea. It'll soon begin its descent. The
flight paths of nine oh seven and nine five eight
(01:00):
are going to cross. That's not a problem, of course,
as long as they're at different altitudes. But they're currently
on course to be at pretty similar altitudes. No need
to panic. This kind of thing happens all the time.
We simply need one of the planes to go a
bit higher or the other to go a bit lower.
(01:21):
As long as they don't both do the same thing,
they'll be fine. Modern airplanes have an automated system for
situations like this. It's called TEA CASS. The Traffic Collision
Avoidance System TEA CASS kicks in now. In the cockpit
of flight nine five eight. It tells the pilot to descend, descend, descend, descend.
(01:46):
The pilot starts to descend. In the cockpit of flight
nine oh seven, Tea cast tells the pilot to climb, climb, climb, climb,
but down on the ground. A twenty six year old
trainee air traffic controller has also noticed that flights nine
(02:07):
oh seven and nine of eight iron a collision course,
and he's issued an instruction of his own j A
L nine O seven descend and maintain flight level three fifty.
Begin descent due to traffic hang on nine O seven.
Isn't nine O seven the one that's supposed to be climbing, Yes,
(02:29):
it is. The trainee air traffic controller has got his
planes muddled up. He meant to say nine eight. So
now the pilot of flight nine O seven has got
a decision to make. On the one hand, he's got
an air traffic controller telling him to descend. On the
other hand, Tea Cass is insisting he has to climb, climb, climb, climb.
(02:54):
He decides to descend. This isn't good. Both nine O
seven and nine five eight and now descending, So there's
a real risk that they're going to be at the
same altitudes when they're fly paths into sect The trainee
air controller's supervisor sees the data and intervenes to put
(03:16):
things right. Jine seven, climb and maintain flight level three
ninety Hang one, there is no nine five seven. The
boss meant to say nine oh seven, but confused her numbers.
In the cockpit of flight nine seven, the pilot hears
(03:37):
the message and thinks that's not for me. Then he
sees flight nine five eight to the cockpit window. It's
alarmingly close, and he's heading straight for it. I'm Tim Harford,
and you're listening to cautionary tales. In the cockpit of
(04:20):
Japanese Airlines flight nine oh seven, the pilot has another
decision to make, and this time he has just a
split second to make it. How is he going to
avoid smashing into flight nine five eight? He slams his
plane into a nose dye. Back in the cabin, the
(04:41):
passengers who've undone their seat belts are suddenly hurled out
of their seats. Some of them hit the ceiling, so
do the cabin attendants who are pushing the drinks trolleys.
So do the drinks trolleys. Hop tea flies everywhere, the
boy is catapulted over four rows of seats, A middle
aged woman breaks her leg. A hundred people are injured,
(05:06):
nine of them seriously, but at least they're alive. It
could have been so much worse. Japan's Ministry of Transport
asks its Accidents Investigation Commission to look into what had
happened and what might be done to lower the risk
that it happens again. One problem, obviously, was that the
(05:28):
trainee air traffic controller and his boss had got their
flight numbers muddled up. But if you're a loyal listener
to cautionary tales, you'll know that there's a common theme
in stories about people screwing up. That theme is that
people screw up all of us from time to time.
So if we want to reduce the risk of a repeat,
we can't rely on saying to air traffic controllers do better.
(05:53):
We need to look at how they operate. Can we
change anything to make it less likely that they'll screw up?
And when screw ups happen anyway, as they will, how
can we make it less likely that they'll lead to
tragic consequences? On that last point, think about the dilemma
faced by the pilot of flight nine oh seven. He's
(06:13):
got the air traffic controller telling him to descend and
Tea Cass telling him to climb. Which one should he
listen to? Tea Cass was new enough that this question
simply hadn't come up before, But it turns out there's
a clear right answer. He should listen to Tea Cass.
(06:34):
Like all automated systems, it's not infallible that when two
planes are heading straight towards each other and there's less
than a minute to keep them apart, Tea Cass is
much more likely than a human on the ground to
have the latest information and give quick and appropriate instructions.
The Japanese investigators can pile a report in which they'll
(06:54):
recommend an overhaul in how pilots are trained, so that
in future pilots will have no doubt that Tea Cass
takes priority. Seventeen months after the near miss, the report
is almost ready to be published. Meanwhile, in Moscow, forty
(07:15):
six school children aboarding a plane to Barcelona. It's the
first of July two thousand and two. The children, mostly teenagers,
are excited. They're going to experience Catalan culture and hang
out on the beach. They've already traveled hundreds of miles
from their home city of Oufar to the east in
(07:37):
the Ural mountains. But they're not the only ones on
the flight. Spetlana Kalaieva lives in Vladikavkas in the north
of Setia Alania Republic. Her husband Vitali, is working as
an architect in Barcelona. Spetlana is flying out to visit
with their ten year old son and four year old daughter,
(07:58):
but they've missed their transfer in Moscow. As luck would
have it, there are plenty of spare seats on this
charter flight from the kids from Oufar. Sped Lana and
the children get on board. The plane takes off from
Moscow in the early evening. Three hours later, it's cruising
(08:19):
over Switzerland. Out of the cockpit window, the pilot and
co pilot see the strobing lights of another plane in
the distance. It's hard to judge at nighttime how far
away another plane is, or how high it is, or
where it's going. But if they need to take evasive action,
(08:39):
they'll be told. And sure enough, here comes a message
from the air traffic controller in Zurich. Descend flight level
three fifty expedite. I have crossing traffic flight level three
fifty that means thirty five thousand feet. They're currently at
thirty six thousand feet. They start to descend, but then climb, climb, climb, climb.
(09:06):
What to do? The pilot and co pilot have both
been properly trained in flying their plane, the tv TU
one five four, but even if they'd memorize the operating
manual word for word, it wouldn't help them much. One
section prohibits initiating a maneuver contrary to a t CASS instruction,
(09:28):
but another section stresses how important it is to follow
the instructions of air traffic control and describes TECSS merely
as an additional system taken together that could be clearer.
The manual for t CASS itself isn't much better. One
part says that if a t CASS instruction is inconsistent
(09:50):
with current clearance from air traffic control, the pilot must
not delay in following the t CASS instruction, But another
part describes te CASS as a mere backup to air
traffic control. So you can understand why the pilot and
the copilot aren't immediately sure which voice to ignore. The
(10:11):
automated voice of Teacas or the human voice of the
Zurich air traffic controller. Climb, climb, climb, climb, it's saying, climb,
but he's guiding us down. Descend. They keep descending, and
here's the air traffic controller again repeating that instruction. Descend
(10:31):
level three fifty expedite descend copy. Yes, we have traffic
at you're two o'clock. Now at three to sixty. The
pilots descend even faster, but two o'clock. That means to
the right. They look out of the cockpit window to
the right. There's no sign of the other airplane. Where
is it here on the left? Increased climb, increased climb,
(10:52):
increased climb, it says, climb. There are no more words
recorded on the black box, but it does record an action,
a desperate tug at the control column. The pilots trying
at last to climb, but it's too late. As they
cross the path of the other plane, their wing slices
(11:13):
into its tail. Their plane breaks up. The plane they
hit catches fire. Both tumble from the sky. The wreckage
falls over hundreds of square kilometers near Uberlingen, just over
the Swiss German border. There are no survivors. How could
(11:37):
this happen? It seems incomprehensible. The next day, parents in
Oufar receive the devastating news in Barcelona, so does the
architect and doting father, Vitali Kaloyev. Cautionary tales will return
(12:01):
in a moment. Just eleven days after the crash over Uberlingen,
the Japanese investigators publish their report on the near miss.
Pilots training needs to change, it says, so they know
(12:23):
that Tea Cass Trump's air traffic control when the two
give opposing instructions. Now a German investigation team looks into
the collision over Uberlingen, among other things. Their report makes
much the same point. The instructions for Tea Cass, they find,
are not standardized, incomplete, and partially contradictory. The training and
(12:47):
instructions have since changed, so no pilot should now make
the same mistake, and in case they do, Tea Cass
has changed two. It now monitors whether both pilots are
obeying it and reverses orders if one is not. In
both Japan and Uberlingen, that would have kept the planes apart.
(13:09):
At the last moment. The pilot who had been descending
because tea cast told them to descend would now be
told to climb instead. The pilot who had been descending
in spite of Tea Cass would now find tea cast
telling them to keep doing what they were doing anyway.
But let's not forget that these incidents weren't all down
to Tea Cass. It's never just one thing, is it.
(13:31):
The floors in Tea Cass came to light only because
the air traffic controllers screwed up in Japan, as we've heard,
one was still in training. But what went wrong in Zurich.
On the evening of July the first, Peter Nielsen turns
up for his night shift with Skyguide, the company that
(13:53):
runs Zurich's air traffic control. Peter Nielsen is thirty five
years old. He's qualified and experienced, His colleagues said the
excellent investigators considered him to be a competent, knowledgeable and
professional air traffic controller, a team player, a nice guy.
The staffing level for night shifts in Zurich had recently changed.
(14:16):
In the past, there'd always been three controllers on shift.
They'd take turns to go for an extended break in
the middle of the shift. And get a bit of
sleep in the staff lounge. That was perfectly safe. There
went enough planes in the dead of night to keep
even two controllers occupied, and the third would return refreshed
as traffic picked up in the morning. But Skyguide had
(14:39):
become short staffed. They'd started putting only two controllers on
at night. The controllers continued their informal arrangement that one
would go to the lounge for a snooze. That was
considerably less safe. Yes, as long as nothing unusual occurred,
one controller could get through the quiet nighttime hours easily enough.
(15:01):
But if something out of the ordinary were to happen,
the controller would have nobody to turn to for a
sense check, and if the low own controller screws up,
there's no colleague there to notice. At quarter past eleven,
Peter Nielsen and his colleague agree that they'll now be
few enough flights coming through that the colleague can retire
(15:21):
to the lounge and return in a few hours. There
is something unusual happening tonight, though, and Nielsen is already
aware of it. Technicians are doing maintenance work on some
of the systems. They tell him those systems are now
in fallback mode. That's fine, he says. Nobody checks if
he understands exactly what fallback mode means. It later transpires
(15:47):
that he doesn't. Here's one thing. It means the radar
screens no longer display a scale, and Nielsen has to
monitor two screens which use different scales. Without the visual aid,
there's more risk of misperceiving how far apart planes are. Also,
the screens aren't automatically going which blip on the radar
(16:11):
corresponds to which plane, and the short term conflict alert
system is partly disengaged. Normally, this system shows a warning
on the radar screen with two minutes notice if planes
are on course to pass within a few miles of
each other. Now they'll just be an audible alarm if
a collision is much more imminent. None of these systems
(16:36):
are critical. Nielsen should be able to compensate for their
absence by making sure he pays a bit more attention.
But he isn't really aware that he needs to. And
what's this on his radar screen. It's a plane He
wasn't expecting to have to deal with. An airbus that
should have landed much earlier but got delayed. Nielsen and
(16:58):
his colleague could completely forgotten that the airbus would be
coming along. If they'd remembered, the colleague would have stayed
for another half hour to handle it. At half past eleven,
the Russian plane enters Nielsen's airspace and the pilot checks
in with him. It's flying at thirty six thousand feet.
The radar shows Nielsen that there's another plane at thirty
(17:19):
six thousand feet, a cargo flight from Bahrain to Brussels.
The planes are approaching each other roughly at right angles.
They're still over fifty miles apart. It sounds like a lot,
but there'll be upon each other in barely five minutes.
If he'd been paying more attention, Nielsen would have told
(17:40):
the Russian pilot to descend, But with so many systems down,
he doesn't notice. And now this delayed airbus wants his attention.
Nielsen has to move to a different workstation to talk
to it and tune into a different frequency. The airbus
wants permission to land on an alternative runway that's a pane.
(18:01):
Nielsen will need to phone the airport to check that
it's okay, and the main phone system is yet another
thing that's down for maintenance. There's a backup phone system
that should still work, but for some reason, Nielsen can't
get through. That's weird. He dials again and again. It
later turns out there's a software glitch with the backup
(18:22):
phone system. Nielsen doesn't know that. He assumes he must
be dialing the wrong number. He tries seven times to
get through. He's got half an eye on the radar screen,
but it isn't showing any warnings. It would be by
now if the short term conflict alert system was working properly,
(18:42):
but it isn't, and Nielsen doesn't know that. The airspace
next to Zurix is handled by another control center in
Carl's Rue, Germany. The controllers there see the short term
conflict alert pop up on their radar screens. Remember that
alert means two planes will be perilously close to each
(19:04):
other in just two minutes. The Carl's Rwer controllers could
jump on the emergency radio frequency to talk to the
two planes, but the rules say they shouldn't do that
for the very good reason that the planes aren't in
their airspace. Instead, the rules say they have to contact Zurich,
so they try, but of course, the phone system in
(19:27):
Zurich isn't working. They try again, and again, they try
eleven times. Nearly five minutes after the Russian plane entered
his airspace, Nielsen suddenly realizes the danger. Descend flight level
pre fifty expedite. I have crossing perfect. The Russian crew
(19:51):
don't respond. Why aren't they responding? We know why. It's
because the pilot and copilot are busy debating whether they
should ignore Nielsen telling them to descend or tea Cass
telling them to climb. It hasn't occurred to Nielsen that
tea casks will have kicked. And now the audible conflict
(20:11):
alert sounds. The two planes are just half a minute
from colliding. Nielsen leaps into action. Descend level three fifty expedite. Descend.
We have traffic at you're two o'clock now at three sixty.
Nielsen is stressed. He's not thinking straight. He doesn't realize
that he's contradicting Tea Cass. But more than that, he
said two o'clock when he meant ten o'clock. It makes
(20:33):
the pilots look right when the cargo plane is to
their left and his radar display is out of date.
The cargo plane isn't now at three sixty. It's been
descending because Tea Cass has told it to the Next
time Nielsen's radar refreshes, it shows the cargo plane level
with the Russian plane and descending at the same rate.
(20:55):
The pilot of the cargo plane comes on the radio
two to inform Nielsen that he's descending, but Nielsen doesn't
see the radar refresh, and he doesn't hear the cargo
pilot's call because he thinks he's averted the Dane. He's
gone back to his other workstation to deal with a
late running airbus. Instead. In Karl's room, the air traffic
(21:18):
controller's watch in horror as the two dots on the
radar collide. By the time Nielsen looks back at his screen,
it's already happened. He tries to call the Russian plane,
there's no response. Bitari Kaloyev knows his wife and children
(21:40):
were on that plane. He hurries to Uberlingen, expecting the worst,
but nothing could have prepared him for the horrors he
was about to see. Rescuers are still searching for all
the bodies. They're scattered over hundreds of square kilometers. The
body of Kaloyev's wife, swet Lana has landed in a cornfield,
(22:03):
his ten year old son on asphalt near a bush shelter.
The little body of his four year old daughter was
found snagged up in a tree. When Calloiev searches the area,
he finds her pearl necklace lying on the forest floor.
Colloiev cleans the bodies and dresses them for the funeral.
(22:28):
He also asks questions of journalists the air traffic controller
what's his name and where does he live? Cautionary tales
will return. The Swiss air traffic control company Skyguide, had
(23:05):
recently come up with new procedures that were meant to
allow controllers to work safely alone when needed. Swiss regulators
were already worried about those procedures. Were they two las
too risky? But Peter Nielsen wasn't even working under these
new procedures. They applied only when there was officially just
(23:27):
one controller on duty during nightshifts. Officially two controllers were
on duty at all times. The fact that one of
them always spent a few hours asleep was just an
informal arrangement, But it was an arrangement that the managers
at Skyguide knew all about. They'd already had to investigate
(23:47):
one near miss. When Skyguide came up with their new
procedures for solo working. They assumed that if only one
controller was on duty, they'd at least have a supervisor
they could call on for help. But that didn't happen.
On the night shift. When one controller slept, there was
no supervisor. Nielsen had to supervise himself. The procedures also
(24:12):
assumed that the controller would have the short term conflict
alert system to rely on. Taking that system offline for
maintenance would have breached the procedures, but of course Nielsen
wasn't protected by these procedures, procedures that the regulators already
worried might not be safe enough. No wonder the investigation
(24:34):
report comes across as pretty sympathetic to Peter Nielsen. He
screwed up, of course he did, but his employers had
allowed a workplace culture to develop in which screw ups
were disturbingly likely. Nielsen was not in a position to
safely execute all the tasks he had been given. The
(24:55):
investigators found Nielsen was traumatized by his role in the collision.
He was treated for shock, but after some time off,
he returned to work. Nearly two years after the accident,
Peter Nielsen was at home with his wife and three
children when he saw a middle aged man sitting in
(25:15):
his front garden. He went outside to find out who
the man was and what he wanted. His children followed
him out. He waved them back inside. We don't know
for sure what happened next. We only have Vitali Kaloyev's
side of the encounter. He says he tried to say
the German words for I am from Russia. He says
(25:38):
he gestured to the front door to show that he
expected Nielsen to invite him in. He says he tried
to show Nielsen photos of the bodies of his dead children,
and he says Nielsen pushed his hand aside and the
photos fell to the ground. In Kaloyev's telling, what happened
(25:59):
next is a blank, but Peter Nielsen's wife can pick
up the story. She heard a scream, she rushed outside
to find Kaloye of walking calmly away with a switchblade knife,
and her husband lying in a pool of his own blood.
(26:23):
It's never just one thing, is it. If Nielsen's colleague
had stayed for another half an hour, if Nielsen had
known that the alert system wasn't working, if the backup
phone line hadn't had a software glitch, if the pilots
had been trained to prioritize teacass maybe you can think
of it as a series of dominoes falling one toppling another,
(26:45):
then another. That's a metaphor one pioneering safety researcher came
up with Herbert Heinrich in his nineteen thirty one book
Industrial Accident Prevention. Or think of the Swiss cheese metaphor
developed more recently by the psychologist James Reason. Each slice
of cheese is a layer of defense, and each has
(27:07):
holes in accidents when you have a stack of slices
and the holes just happen to line up. Peter Nielsen's
screw up was one hole in a slice of cheese,
but it wouldn't have mattered if there hadn't been other
holes in other slices. Sometimes we can reasonably hold people
(27:30):
responsible for gaping holes in a slice of cheese. A
Swiss court find managers at Skyguide for having allowed a
culture of negligence to develop in the workplace. At other times,
there's really nobody at whom you can point a finger.
The people who train pilots or right operating manuals hadn't
(27:50):
been sloppy or reckless. They simply hadn't foreseen that you
might get dangerous circumstances in which tea cass is saying
one thing and air traffic controllers are saying another. Once
it became clear that this could happen, they changed the
training and rewrote the manuals. That slice of cheese now
has smaller holes. Still, even when there isn't any one
(28:14):
obvious to punish, people can get punished anyway. Remember the
twenty six year old trainee air traffic controller in Japan
who had said flight nine oh seven when he meant
flight nine five eight. Remember the supervisor who jumbled her
(28:35):
numbers and said nine five seven. It's the same kind
of flub you might think that could happen to anyone,
and would hardly ever lead to tragedy. They'd usually be
plenty of other slices of cheese to cover the hole.
The Tokyo Metropolitan Police Department wasn't so forgiving. It was
professional negligence, they said. Prosecutors brought the pair to court.
(28:59):
They demanded eighteen months in prison for the supervisor they
cut the trainee a bit of slack. They wanted just
twelve months for him. The case rumbled on for five years,
during which both kept working at Tokyo Air Traffic Control.
At last, the district court delivered its verdict, acquitted on
(29:22):
all counts. The controller's legal ordeals seemed finally to be over,
and they wrote an open letter to the International Federation
of Air Traffic Controllers Associations to say thank you for
all the support they'd received from their professional colleagues around
the world. The court recognized that it was an accident
(29:44):
connected with a system rather than individuals. They wrote, we
think the collision above Uberlingen might have been prevented if
the causes that led to our accidents had been properly
clarified at an earlier stage and notified worldwide. This not
guilty verdict is not only ours, but also for all
of those who supported us. But the prosecutors lodged an appeal.
(30:10):
They weren't ready to give up yet. Vitali Kaloyev walked
back to his hotel, the Welcome Inn, near Zurich Airport,
having revenged himself upon Peter Nielsen. He was covered in
the air traffic controller's blood. Somehow the staff didn't see
(30:32):
him make his way up to his king size room.
The next day police came to the hotel to arrest him.
The charge was murder. Peter Nielsen had bled to death.
Vitali was held at first in a mental hospital, then
tried and sentenced to eight years in a Swiss prison.
(30:57):
Just two years later he was out. An appeal court
decided that he couldn't be held fully accountable for his actions.
The most shocking thing about Vitali Kaloyev's murder of Peter
Nielsen isn't the murder itself. The most shocking thing was
the public reaction to Vitali Kaloyev. When he got out
(31:20):
of prison and went home to North Ossetia. It was
a hero's welcome. He got fan mail, letters of support,
offers of marriage. If more people were like you, wrote
one woman, the world would be a better place. He's
a real man, said one local dignitary. What he did
was an act of heroism. Journalists in Ossetia named him
(31:44):
Man of the Year. The government of North Ossetia supported
Kaloyev two They even appointed him Deputy Minister for Construction
When he retired. They gave him the Glory of Ossetia Medal, awarded,
among other things, for maintaining law and order. One man's
(32:06):
grief fueled madness is understand The support from many others
says something more troubling about the human condition. In any accident,
there are lots of lessons we might learn about how
to make future accidents less likely. Rewrite instructions, change workplace culture,
(32:31):
tweak automated systems, but punish people for getting in a muddle.
I'm not so sure that helps. The prosecutors in Japan
took a different view. They pursued their case against the
two air traffic controllers for another five years, until at
last the Supreme Court handed down the final verdict guilty.
(32:57):
The sentences at least were suspended. They wouldn't go to
prison unless they committed some other crime, such as maybe
mixing up their flight numbers again. But they wouldn't need
to worry about that because as convicted criminals, they lost
their jobs. It's never just one thing. But shades of
(33:17):
gray aren't satisfying. It seems we thirst for black and white.
We want villains, and we want vengeance. For a full
(33:45):
list of our sources Please see the show notes at
Tim Harford dot com. Cautionary Tales is written by me
Tim Harford with Andrew Wright. It's produced by Alice Fines
with support from Edith Ruslow. The sound design and original
music is the work of Pascal Wise. The show wouldn't
(34:07):
have been possible without the work of J. K. Weisberg,
Ryan Dilley, Julia Barton, Gretta Cone, Little Millard, John schnars
Kylie Migliori, Eric Sandler, Maggie Taylor, Nicole Morano, and Morgan Ratner.
Cautionary Tales he's a production of Pushkin Industries. If you
like the show, please remember to share, rate, and review.
(34:29):
It helps us for mysterious reasons. If you want to
hear the show, add free sign up for Pushkin Plus
on the show page and Apple Podcasts, or at pushkin
dot fm, slash plus
Pushkin. Japanese Airlines flight nine oh seven is flying from
Tokyo to Okinawa. It took off twenty minutes ago, and
it's almost completed its climb to its cruising altitude, close
enough that the fastened seatbelt sign has been switched off
(00:38):
and the cabin attendants are serving hot tea. The year
is two thousand and one. The airspace around Tokyo is busy.
Another Japanese Airlines plane, flight nine five eight, is coming
in from South Korea. It'll soon begin its descent. The
flight paths of nine oh seven and nine five eight
(01:00):
are going to cross. That's not a problem, of course,
as long as they're at different altitudes. But they're currently
on course to be at pretty similar altitudes. No need
to panic. This kind of thing happens all the time.
We simply need one of the planes to go a
bit higher or the other to go a bit lower.
(01:21):
As long as they don't both do the same thing,
they'll be fine. Modern airplanes have an automated system for
situations like this. It's called TEA CASS. The Traffic Collision
Avoidance System TEA CASS kicks in now. In the cockpit
of flight nine five eight. It tells the pilot to descend, descend, descend, descend.
(01:46):
The pilot starts to descend. In the cockpit of flight
nine oh seven, Tea cast tells the pilot to climb, climb, climb, climb,
but down on the ground. A twenty six year old
trainee air traffic controller has also noticed that flights nine
(02:07):
oh seven and nine of eight iron a collision course,
and he's issued an instruction of his own j A
L nine O seven descend and maintain flight level three fifty.
Begin descent due to traffic hang on nine O seven.
Isn't nine O seven the one that's supposed to be climbing, Yes,
(02:29):
it is. The trainee air traffic controller has got his
planes muddled up. He meant to say nine eight. So
now the pilot of flight nine O seven has got
a decision to make. On the one hand, he's got
an air traffic controller telling him to descend. On the
other hand, Tea Cass is insisting he has to climb, climb, climb, climb.
(02:54):
He decides to descend. This isn't good. Both nine O
seven and nine five eight and now descending, So there's
a real risk that they're going to be at the
same altitudes when they're fly paths into sect The trainee
air controller's supervisor sees the data and intervenes to put
(03:16):
things right. Jine seven, climb and maintain flight level three
ninety Hang one, there is no nine five seven. The
boss meant to say nine oh seven, but confused her numbers.
In the cockpit of flight nine seven, the pilot hears
(03:37):
the message and thinks that's not for me. Then he
sees flight nine five eight to the cockpit window. It's
alarmingly close, and he's heading straight for it. I'm Tim Harford,
and you're listening to cautionary tales. In the cockpit of
(04:20):
Japanese Airlines flight nine oh seven, the pilot has another
decision to make, and this time he has just a
split second to make it. How is he going to
avoid smashing into flight nine five eight? He slams his
plane into a nose dye. Back in the cabin, the
(04:41):
passengers who've undone their seat belts are suddenly hurled out
of their seats. Some of them hit the ceiling, so
do the cabin attendants who are pushing the drinks trolleys.
So do the drinks trolleys. Hop tea flies everywhere, the
boy is catapulted over four rows of seats, A middle
aged woman breaks her leg. A hundred people are injured,
(05:06):
nine of them seriously, but at least they're alive. It
could have been so much worse. Japan's Ministry of Transport
asks its Accidents Investigation Commission to look into what had
happened and what might be done to lower the risk
that it happens again. One problem, obviously, was that the
(05:28):
trainee air traffic controller and his boss had got their
flight numbers muddled up. But if you're a loyal listener
to cautionary tales, you'll know that there's a common theme
in stories about people screwing up. That theme is that
people screw up all of us from time to time.
So if we want to reduce the risk of a repeat,
we can't rely on saying to air traffic controllers do better.
(05:53):
We need to look at how they operate. Can we
change anything to make it less likely that they'll screw up?
And when screw ups happen anyway, as they will, how
can we make it less likely that they'll lead to
tragic consequences? On that last point, think about the dilemma
faced by the pilot of flight nine oh seven. He's
(06:13):
got the air traffic controller telling him to descend and
Tea Cass telling him to climb. Which one should he
listen to? Tea Cass was new enough that this question
simply hadn't come up before, But it turns out there's
a clear right answer. He should listen to Tea Cass.
(06:34):
Like all automated systems, it's not infallible that when two
planes are heading straight towards each other and there's less
than a minute to keep them apart, Tea Cass is
much more likely than a human on the ground to
have the latest information and give quick and appropriate instructions.
The Japanese investigators can pile a report in which they'll
(06:54):
recommend an overhaul in how pilots are trained, so that
in future pilots will have no doubt that Tea Cass
takes priority. Seventeen months after the near miss, the report
is almost ready to be published. Meanwhile, in Moscow, forty
(07:15):
six school children aboarding a plane to Barcelona. It's the
first of July two thousand and two. The children, mostly teenagers,
are excited. They're going to experience Catalan culture and hang
out on the beach. They've already traveled hundreds of miles
from their home city of Oufar to the east in
(07:37):
the Ural mountains. But they're not the only ones on
the flight. Spetlana Kalaieva lives in Vladikavkas in the north
of Setia Alania Republic. Her husband Vitali, is working as
an architect in Barcelona. Spetlana is flying out to visit
with their ten year old son and four year old daughter,
(07:58):
but they've missed their transfer in Moscow. As luck would
have it, there are plenty of spare seats on this
charter flight from the kids from Oufar. Sped Lana and
the children get on board. The plane takes off from
Moscow in the early evening. Three hours later, it's cruising
(08:19):
over Switzerland. Out of the cockpit window, the pilot and
co pilot see the strobing lights of another plane in
the distance. It's hard to judge at nighttime how far
away another plane is, or how high it is, or
where it's going. But if they need to take evasive action,
(08:39):
they'll be told. And sure enough, here comes a message
from the air traffic controller in Zurich. Descend flight level
three fifty expedite. I have crossing traffic flight level three
fifty that means thirty five thousand feet. They're currently at
thirty six thousand feet. They start to descend, but then climb, climb, climb, climb.
(09:06):
What to do? The pilot and co pilot have both
been properly trained in flying their plane, the tv TU
one five four, but even if they'd memorize the operating
manual word for word, it wouldn't help them much. One
section prohibits initiating a maneuver contrary to a t CASS instruction,
(09:28):
but another section stresses how important it is to follow
the instructions of air traffic control and describes TECSS merely
as an additional system taken together that could be clearer.
The manual for t CASS itself isn't much better. One
part says that if a t CASS instruction is inconsistent
(09:50):
with current clearance from air traffic control, the pilot must
not delay in following the t CASS instruction, But another
part describes te CASS as a mere backup to air
traffic control. So you can understand why the pilot and
the copilot aren't immediately sure which voice to ignore. The
(10:11):
automated voice of Teacas or the human voice of the
Zurich air traffic controller. Climb, climb, climb, climb, it's saying, climb,
but he's guiding us down. Descend. They keep descending, and
here's the air traffic controller again repeating that instruction. Descend
(10:31):
level three fifty expedite descend copy. Yes, we have traffic
at you're two o'clock. Now at three to sixty. The
pilots descend even faster, but two o'clock. That means to
the right. They look out of the cockpit window to
the right. There's no sign of the other airplane. Where
is it here on the left? Increased climb, increased climb,
(10:52):
increased climb, it says, climb. There are no more words
recorded on the black box, but it does record an action,
a desperate tug at the control column. The pilots trying
at last to climb, but it's too late. As they
cross the path of the other plane, their wing slices
(11:13):
into its tail. Their plane breaks up. The plane they
hit catches fire. Both tumble from the sky. The wreckage
falls over hundreds of square kilometers near Uberlingen, just over
the Swiss German border. There are no survivors. How could
(11:37):
this happen? It seems incomprehensible. The next day, parents in
Oufar receive the devastating news in Barcelona, so does the
architect and doting father, Vitali Kaloyev. Cautionary tales will return
(12:01):
in a moment. Just eleven days after the crash over Uberlingen,
the Japanese investigators publish their report on the near miss.
Pilots training needs to change, it says, so they know
(12:23):
that Tea Cass Trump's air traffic control when the two
give opposing instructions. Now a German investigation team looks into
the collision over Uberlingen, among other things. Their report makes
much the same point. The instructions for Tea Cass, they find,
are not standardized, incomplete, and partially contradictory. The training and
(12:47):
instructions have since changed, so no pilot should now make
the same mistake, and in case they do, Tea Cass
has changed two. It now monitors whether both pilots are
obeying it and reverses orders if one is not. In
both Japan and Uberlingen, that would have kept the planes apart.
(13:09):
At the last moment. The pilot who had been descending
because tea cast told them to descend would now be
told to climb instead. The pilot who had been descending
in spite of Tea Cass would now find tea cast
telling them to keep doing what they were doing anyway.
But let's not forget that these incidents weren't all down
to Tea Cass. It's never just one thing, is it.
(13:31):
The floors in Tea Cass came to light only because
the air traffic controllers screwed up in Japan, as we've heard,
one was still in training. But what went wrong in Zurich.
On the evening of July the first, Peter Nielsen turns
up for his night shift with Skyguide, the company that
(13:53):
runs Zurich's air traffic control. Peter Nielsen is thirty five
years old. He's qualified and experienced, His colleagues said the
excellent investigators considered him to be a competent, knowledgeable and
professional air traffic controller, a team player, a nice guy.
The staffing level for night shifts in Zurich had recently changed.
(14:16):
In the past, there'd always been three controllers on shift.
They'd take turns to go for an extended break in
the middle of the shift. And get a bit of
sleep in the staff lounge. That was perfectly safe. There
went enough planes in the dead of night to keep
even two controllers occupied, and the third would return refreshed
as traffic picked up in the morning. But Skyguide had
(14:39):
become short staffed. They'd started putting only two controllers on
at night. The controllers continued their informal arrangement that one
would go to the lounge for a snooze. That was
considerably less safe. Yes, as long as nothing unusual occurred,
one controller could get through the quiet nighttime hours easily enough.
(15:01):
But if something out of the ordinary were to happen,
the controller would have nobody to turn to for a
sense check, and if the low own controller screws up,
there's no colleague there to notice. At quarter past eleven,
Peter Nielsen and his colleague agree that they'll now be
few enough flights coming through that the colleague can retire
(15:21):
to the lounge and return in a few hours. There
is something unusual happening tonight, though, and Nielsen is already
aware of it. Technicians are doing maintenance work on some
of the systems. They tell him those systems are now
in fallback mode. That's fine, he says. Nobody checks if
he understands exactly what fallback mode means. It later transpires
(15:47):
that he doesn't. Here's one thing. It means the radar
screens no longer display a scale, and Nielsen has to
monitor two screens which use different scales. Without the visual aid,
there's more risk of misperceiving how far apart planes are. Also,
the screens aren't automatically going which blip on the radar
(16:11):
corresponds to which plane, and the short term conflict alert
system is partly disengaged. Normally, this system shows a warning
on the radar screen with two minutes notice if planes
are on course to pass within a few miles of
each other. Now they'll just be an audible alarm if
a collision is much more imminent. None of these systems
(16:36):
are critical. Nielsen should be able to compensate for their
absence by making sure he pays a bit more attention.
But he isn't really aware that he needs to. And
what's this on his radar screen. It's a plane He
wasn't expecting to have to deal with. An airbus that
should have landed much earlier but got delayed. Nielsen and
(16:58):
his colleague could completely forgotten that the airbus would be
coming along. If they'd remembered, the colleague would have stayed
for another half hour to handle it. At half past eleven,
the Russian plane enters Nielsen's airspace and the pilot checks
in with him. It's flying at thirty six thousand feet.
The radar shows Nielsen that there's another plane at thirty
(17:19):
six thousand feet, a cargo flight from Bahrain to Brussels.
The planes are approaching each other roughly at right angles.
They're still over fifty miles apart. It sounds like a lot,
but there'll be upon each other in barely five minutes.
If he'd been paying more attention, Nielsen would have told
(17:40):
the Russian pilot to descend, But with so many systems down,
he doesn't notice. And now this delayed airbus wants his attention.
Nielsen has to move to a different workstation to talk
to it and tune into a different frequency. The airbus
wants permission to land on an alternative runway that's a pane.
(18:01):
Nielsen will need to phone the airport to check that
it's okay, and the main phone system is yet another
thing that's down for maintenance. There's a backup phone system
that should still work, but for some reason, Nielsen can't
get through. That's weird. He dials again and again. It
later turns out there's a software glitch with the backup
(18:22):
phone system. Nielsen doesn't know that. He assumes he must
be dialing the wrong number. He tries seven times to
get through. He's got half an eye on the radar screen,
but it isn't showing any warnings. It would be by
now if the short term conflict alert system was working properly,
(18:42):
but it isn't, and Nielsen doesn't know that. The airspace
next to Zurix is handled by another control center in
Carl's Rue, Germany. The controllers there see the short term
conflict alert pop up on their radar screens. Remember that
alert means two planes will be perilously close to each
(19:04):
other in just two minutes. The Carl's Rwer controllers could
jump on the emergency radio frequency to talk to the
two planes, but the rules say they shouldn't do that
for the very good reason that the planes aren't in
their airspace. Instead, the rules say they have to contact Zurich,
so they try, but of course, the phone system in
(19:27):
Zurich isn't working. They try again, and again, they try
eleven times. Nearly five minutes after the Russian plane entered
his airspace, Nielsen suddenly realizes the danger. Descend flight level
pre fifty expedite. I have crossing perfect. The Russian crew
(19:51):
don't respond. Why aren't they responding? We know why. It's
because the pilot and copilot are busy debating whether they
should ignore Nielsen telling them to descend or tea Cass
telling them to climb. It hasn't occurred to Nielsen that
tea casks will have kicked. And now the audible conflict
(20:11):
alert sounds. The two planes are just half a minute
from colliding. Nielsen leaps into action. Descend level three fifty expedite. Descend.
We have traffic at you're two o'clock now at three sixty.
Nielsen is stressed. He's not thinking straight. He doesn't realize
that he's contradicting Tea Cass. But more than that, he
said two o'clock when he meant ten o'clock. It makes
(20:33):
the pilots look right when the cargo plane is to
their left and his radar display is out of date.
The cargo plane isn't now at three sixty. It's been
descending because Tea Cass has told it to the Next
time Nielsen's radar refreshes, it shows the cargo plane level
with the Russian plane and descending at the same rate.
(20:55):
The pilot of the cargo plane comes on the radio
two to inform Nielsen that he's descending, but Nielsen doesn't
see the radar refresh, and he doesn't hear the cargo
pilot's call because he thinks he's averted the Dane. He's
gone back to his other workstation to deal with a
late running airbus. Instead. In Karl's room, the air traffic
(21:18):
controller's watch in horror as the two dots on the
radar collide. By the time Nielsen looks back at his screen,
it's already happened. He tries to call the Russian plane,
there's no response. Bitari Kaloyev knows his wife and children
(21:40):
were on that plane. He hurries to Uberlingen, expecting the worst,
but nothing could have prepared him for the horrors he
was about to see. Rescuers are still searching for all
the bodies. They're scattered over hundreds of square kilometers. The
body of Kaloyev's wife, swet Lana has landed in a cornfield,
(22:03):
his ten year old son on asphalt near a bush shelter.
The little body of his four year old daughter was
found snagged up in a tree. When Calloiev searches the area,
he finds her pearl necklace lying on the forest floor.
Colloiev cleans the bodies and dresses them for the funeral.
(22:28):
He also asks questions of journalists the air traffic controller
what's his name and where does he live? Cautionary tales
will return. The Swiss air traffic control company Skyguide, had
(23:05):
recently come up with new procedures that were meant to
allow controllers to work safely alone when needed. Swiss regulators
were already worried about those procedures. Were they two las
too risky? But Peter Nielsen wasn't even working under these
new procedures. They applied only when there was officially just
(23:27):
one controller on duty during nightshifts. Officially two controllers were
on duty at all times. The fact that one of
them always spent a few hours asleep was just an
informal arrangement, But it was an arrangement that the managers
at Skyguide knew all about. They'd already had to investigate
(23:47):
one near miss. When Skyguide came up with their new
procedures for solo working. They assumed that if only one
controller was on duty, they'd at least have a supervisor
they could call on for help. But that didn't happen.
On the night shift. When one controller slept, there was
no supervisor. Nielsen had to supervise himself. The procedures also
(24:12):
assumed that the controller would have the short term conflict
alert system to rely on. Taking that system offline for
maintenance would have breached the procedures, but of course Nielsen
wasn't protected by these procedures, procedures that the regulators already
worried might not be safe enough. No wonder the investigation
(24:34):
report comes across as pretty sympathetic to Peter Nielsen. He
screwed up, of course he did, but his employers had
allowed a workplace culture to develop in which screw ups
were disturbingly likely. Nielsen was not in a position to
safely execute all the tasks he had been given. The
(24:55):
investigators found Nielsen was traumatized by his role in the collision.
He was treated for shock, but after some time off,
he returned to work. Nearly two years after the accident,
Peter Nielsen was at home with his wife and three
children when he saw a middle aged man sitting in
(25:15):
his front garden. He went outside to find out who
the man was and what he wanted. His children followed
him out. He waved them back inside. We don't know
for sure what happened next. We only have Vitali Kaloyev's
side of the encounter. He says he tried to say
the German words for I am from Russia. He says
(25:38):
he gestured to the front door to show that he
expected Nielsen to invite him in. He says he tried
to show Nielsen photos of the bodies of his dead children,
and he says Nielsen pushed his hand aside and the
photos fell to the ground. In Kaloyev's telling, what happened
(25:59):
next is a blank, but Peter Nielsen's wife can pick
up the story. She heard a scream, she rushed outside
to find Kaloye of walking calmly away with a switchblade knife,
and her husband lying in a pool of his own blood.
(26:23):
It's never just one thing, is it. If Nielsen's colleague
had stayed for another half an hour, if Nielsen had
known that the alert system wasn't working, if the backup
phone line hadn't had a software glitch, if the pilots
had been trained to prioritize teacass maybe you can think
of it as a series of dominoes falling one toppling another,
(26:45):
then another. That's a metaphor one pioneering safety researcher came
up with Herbert Heinrich in his nineteen thirty one book
Industrial Accident Prevention. Or think of the Swiss cheese metaphor
developed more recently by the psychologist James Reason. Each slice
of cheese is a layer of defense, and each has
(27:07):
holes in accidents when you have a stack of slices
and the holes just happen to line up. Peter Nielsen's
screw up was one hole in a slice of cheese,
but it wouldn't have mattered if there hadn't been other
holes in other slices. Sometimes we can reasonably hold people
(27:30):
responsible for gaping holes in a slice of cheese. A
Swiss court find managers at Skyguide for having allowed a
culture of negligence to develop in the workplace. At other times,
there's really nobody at whom you can point a finger.
The people who train pilots or right operating manuals hadn't
(27:50):
been sloppy or reckless. They simply hadn't foreseen that you
might get dangerous circumstances in which tea cass is saying
one thing and air traffic controllers are saying another. Once
it became clear that this could happen, they changed the
training and rewrote the manuals. That slice of cheese now
has smaller holes. Still, even when there isn't any one
(28:14):
obvious to punish, people can get punished anyway. Remember the
twenty six year old trainee air traffic controller in Japan
who had said flight nine oh seven when he meant
flight nine five eight. Remember the supervisor who jumbled her
(28:35):
numbers and said nine five seven. It's the same kind
of flub you might think that could happen to anyone,
and would hardly ever lead to tragedy. They'd usually be
plenty of other slices of cheese to cover the hole.
The Tokyo Metropolitan Police Department wasn't so forgiving. It was
professional negligence, they said. Prosecutors brought the pair to court.
(28:59):
They demanded eighteen months in prison for the supervisor they
cut the trainee a bit of slack. They wanted just
twelve months for him. The case rumbled on for five years,
during which both kept working at Tokyo Air Traffic Control.
At last, the district court delivered its verdict, acquitted on
(29:22):
all counts. The controller's legal ordeals seemed finally to be over,
and they wrote an open letter to the International Federation
of Air Traffic Controllers Associations to say thank you for
all the support they'd received from their professional colleagues around
the world. The court recognized that it was an accident
(29:44):
connected with a system rather than individuals. They wrote, we
think the collision above Uberlingen might have been prevented if
the causes that led to our accidents had been properly
clarified at an earlier stage and notified worldwide. This not
guilty verdict is not only ours, but also for all
of those who supported us. But the prosecutors lodged an appeal.
(30:10):
They weren't ready to give up yet. Vitali Kaloyev walked
back to his hotel, the Welcome Inn, near Zurich Airport,
having revenged himself upon Peter Nielsen. He was covered in
the air traffic controller's blood. Somehow the staff didn't see
(30:32):
him make his way up to his king size room.
The next day police came to the hotel to arrest him.
The charge was murder. Peter Nielsen had bled to death.
Vitali was held at first in a mental hospital, then
tried and sentenced to eight years in a Swiss prison.
(30:57):
Just two years later he was out. An appeal court
decided that he couldn't be held fully accountable for his actions.
The most shocking thing about Vitali Kaloyev's murder of Peter
Nielsen isn't the murder itself. The most shocking thing was
the public reaction to Vitali Kaloyev. When he got out
(31:20):
of prison and went home to North Ossetia. It was
a hero's welcome. He got fan mail, letters of support,
offers of marriage. If more people were like you, wrote
one woman, the world would be a better place. He's
a real man, said one local dignitary. What he did
was an act of heroism. Journalists in Ossetia named him
(31:44):
Man of the Year. The government of North Ossetia supported
Kaloyev two They even appointed him Deputy Minister for Construction
When he retired. They gave him the Glory of Ossetia Medal, awarded,
among other things, for maintaining law and order. One man's
(32:06):
grief fueled madness is understand The support from many others
says something more troubling about the human condition. In any accident,
there are lots of lessons we might learn about how
to make future accidents less likely. Rewrite instructions, change workplace culture,
(32:31):
tweak automated systems, but punish people for getting in a muddle.
I'm not so sure that helps. The prosecutors in Japan
took a different view. They pursued their case against the
two air traffic controllers for another five years, until at
last the Supreme Court handed down the final verdict guilty.
(32:57):
The sentences at least were suspended. They wouldn't go to
prison unless they committed some other crime, such as maybe
mixing up their flight numbers again. But they wouldn't need
to worry about that because as convicted criminals, they lost
their jobs. It's never just one thing. But shades of
(33:17):
gray aren't satisfying. It seems we thirst for black and white.
We want villains, and we want vengeance. For a full
(33:45):
list of our sources Please see the show notes at
Tim Harford dot com. Cautionary Tales is written by me
Tim Harford with Andrew Wright. It's produced by Alice Fines
with support from Edith Ruslow. The sound design and original
music is the work of Pascal Wise. The show wouldn't
(34:07):
have been possible without the work of J. K. Weisberg,
Ryan Dilley, Julia Barton, Gretta Cone, Little Millard, John schnars
Kylie Migliori, Eric Sandler, Maggie Taylor, Nicole Morano, and Morgan Ratner.
Cautionary Tales he's a production of Pushkin Industries. If you
like the show, please remember to share, rate, and review.
(34:29):
It helps us for mysterious reasons. If you want to
hear the show, add free sign up for Pushkin Plus
on the show page and Apple Podcasts, or at pushkin
dot fm, slash plus
Host
Tim Harford
Popular Podcasts
Stuff You Should Know
If you've ever wanted to know about champagne, satanism, the Stonewall Uprising, chaos theory, LSD, El Nino, true crime and Rosa Parks, then look no further. Josh and Chuck have you covered.
Dateline NBC
Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com
New Heights with Jason & Travis Kelce
Football’s funniest family duo — Jason Kelce of the Philadelphia Eagles and Travis Kelce of the Kansas City Chiefs — team up to provide next-level access to life in the league as it unfolds. The two brothers and Super Bowl champions drop weekly insights about the weekly slate of games and share their INSIDE perspectives on trending NFL news and sports headlines. They also endlessly rag on each other as brothers do, chat the latest in pop culture and welcome some very popular and well-known friends to chat with them. Check out new episodes every Wednesday. Follow New Heights on the Wondery App, YouTube or wherever you get your podcasts. You can listen to new episodes early and ad-free, and get exclusive content on Wondery+. Join Wondery+ in the Wondery App, Apple Podcasts or Spotify. And join our new membership for a unique fan experience by going to the New Heights YouTube channel now!