- The level of destruction was enormous. You couldn't tell that you had an Airbus 8310 aircraft there. I mean, you couldn't even
tell you had two engines. (menacing music) - [Narrator] 8:19 p.m. TWA Flight 800 is airborne. - Talk to me. What do yo have for us? - [Narrator] Without
warning, a powerful explosion tears the fuselage apart. Debris from TWA Flight
800 litters the water nearly 75 miles east of Manhattan. Investigators begin the painstaking task of piecing together what
happened to TWA 800. The NTSB's lead investigator, Al Dickinson faces an urgent task. - It was extremely important for us to find out what happened
because there were so many 747s flying at that time. - [Narrator] The NTSB will
lead the investigation. - This is a half mile block here. - [Narrator] While the FBI launches a parallel criminal inquiry. - People think this is exclusive
jurisdiction of the NTSB. That's not correct. If it's a criminal matter, we have to get out there right away. (menacing music) - [Narrator] The FBI believes they may already have an explanation for the disaster over Long Island. Three years earlier in 1993,
terrorists drove a bomb into the World Trade Center. Just over a year before, Timothy McVeigh bombed the
federal building in Oklahoma. Now, the midair explosion of TWA 800 is also being linked to terrorism. - It was all over the news how people thought they
saw something going up to hit an aircraft. A lot of 'em thought they saw missiles. - [Narrator] NTSB
investigators spend weeks carefully searching for
any sign of foul play. (dramatic music) They study wreckage from almost every part of the 230-foot long plane. - Pretty much during the
whole time we were there, we were looking for
something that would support any kind of missile or bomb. - [Narrator] They find no
signs of an explosive device. (solemn music) - No pitting, no cratering, nothing. - We didn't find the set patterns and arraying pattern that
might've been from a bomb. We didn't find this micro cratering where a hot piece of metal are impacting other pieces of metal. - It wasn't a bomb. - [James] No piece had any
evidence of a bomb at all. - [Narrator] NTSB investigators believe it was an exploding fuel
tank that took down TWA 800, but they still don't know
what sparked the blast. - We need to prove three things. The fuel was flammable. The explosion has to be powerful
enough to rupture the tank. And finally, something created
a spark to ignite the fuel. Let's start with the first one. Flammability. (menacing music) - [Narrator] Jet fuel in its
liquid form is not flammable, but when heated, the
fuel starts to vaporize. When combined with oxygen
already present in the tank, this vapor can become highly flammable. At the altitude where TWA 800
exploded, almost 14,000 feet, jet fuel needs to reach
96 degrees Fahrenheit before it can ignite. There's just one problem. - The manufacturers say, well, it never gets that hot in there. - [Narrator] According to
Boeing, the fuel tanks housed inside the wings would
never get hot enough for the fuel to vaporize. On the day of the fatal flight, the temperature at JFK airport
hit 87 degrees Fahrenheit, well below the flashpoint for jet fuel. The NTSB's theory may be wrong. Investigators examine the design
schematics of the aircraft. An intriguing detail
catches their attention. - I remember learning that the placement of the air conditioning
units were underneath the center tank and those
generate a fair amount of heat. - They cool the aircraft,
but the packs themselves could've quite hot during that procedure. - [Narrator] On TWA 800,
the air conditioning units were working extra hard
to keep the cabin cool on a hot evening. - The air conditioning packs underneath the center wing fuel
tank had been operating for, I believe several
hours prior to takeoff. - [Narrator] Could heat from the units have boosted the
temperature inside the tanks to a dangerously high level? - There's only one way to find out. - The only way we were going to determine the actual conditions inside the fuel tank was by performing a flight test. - [Narrator] They decide to
reproduce the exact conditions of the accident flight. - All right, let's start it up. - [Narrator] The same type
of plane, the same fuel load, and most importantly, exactly the same air conditioning units. (plane engine roaring) It's a risky undertaking
filled with uncertainties. The test flight reaches the
same altitude as TWA 800. - Holy Crow. - [Narrator] The temperature
readings are terrifying. - These air conditioner packs were getting up to 350 degrees. 350 degrees is about what
you turn your oven to, to bake a chicken. - This is off the charts. - [Narrator] The temperature in the tank hits 127 degrees Fahrenheit, 30 degrees above the flash point. - Okay, let's get back down to the ground. - [Narrator] Investigators are now certain that the fuel in the tanks of TWA 800 did become flammable. Investigators know the Northwest
Airlink Flight 5719 pilots could not have heard a
low altitude warning, but they still don't
understand why the plane was descending so rapidly. They wonder if weather conditions
may have played a role. They check the temperatures and the type of precipitation
encountered by the turboprop. - These are prime conditions for icing. Plane would have descended
right through it. - [Narrator] Investigators
need to know how bad the icing conditions were
just before the crash. - Just wondering if you
have a couple of minutes. - [Narrator] They talk to other pilots who flew into Hibbing that night. - So you were aware of
the potential foricing during your approach into Hibbing? - [Narrator] The pilots tell DeLisi, they faced moderate icing conditions. - But why would these two pilots start their descent so late? - [Narrator] They also
describe a common technique used to prevent ice accumulation. (plane engine roaring) It now seems the rapid descent was not due to a loss of control caused by icing. Instead, it looks like it was part of a deliberate strategy to avoid icing. Finally, investigators get the evidence they've been waiting for. The cockpit voice recording. - All right, everybody ready? Play the tape. - [Narrator] The
investigators listen carefully to the recording. It's what is not said
that alarms them the most. (dramatic music) - Why isn't the first officer
making his altitude call-outs? - [Narrator] First officer Erickson should be telling his captain how close they are to
their minimum altitude and warning him when they descend past it. But he does neither. - Gear down. Lapse 20. - He never told the captain how close they were getting to the ground. - [Narrator] Captain
Falitz has his hands full landing the plane. He expects his first officer to keep an eye on their altitude. But on this flight, the first officer never once reports the altitude as the plane speeds closer
and closer to the ground. (passengers scream) The CDR leads investigators to wonder. Was the loss of 18 lives
in the Hibbing crash due to the failings of an
inexperienced young pilot? Captain Falitz was known
as a skilled senior pilot, but a deeper look reveals a
man with a troubling record. - When we looked at the
captain's training records, we began to understand that he had some previous
issues in his flight training. - Soon after he joined the
company, he failed his oral exam. He failed two more proficiency
exams in his career. That's unusual for a professional pilot to fail that many times. - The problems hadn't
been tracked by anybody in the organization,
because they had failed at different locations. So nobody put everything
together until we did. (menacing music) - Some of the instructor
pilots were noting that his cockpit resource
management wasn't up to par and that he had a tendency to
be domineering in the cockpit. - Well, he had an issue with
dealing with other people. - Are all these formal complaints
against Captain Falitz? - Marvin was the first captain
I flew with after my IOE, my initial operating experience. And he tended to be a
little bit domineering and would berate you, and was intolerant of mistakes, and really not a particularly
great instructor pilot. - Wow. - [Narrator] Perhaps the
most disturbing complaint against Captain Falitz, is that he once physically
struck a colleague in anger. - For a professional pilot to
physically have an altercation or attempt to quote,
discipline a fellow employee, is totally unacceptable. (dramatic music) - I don't get it. What was making this guy so angry? - You gotta be freaking kidding me. - [Narrator] According
to people who knew him, Captain Falitz's morale took a big hit when Northwest Airlink instituted a new resident's policy for their pilots. - About a year before the company, for cost-saving purposes,
started a new policy where they require the pilots to reside at their outstations. These would be small towns
outside of Minneapolis. - [Narrator] Investigators make another disturbing discovery. Captain Falitz would sometimes
be deliberately rough with the flight controls. - His way of getting
revenge on the company was to sometimes take it
out on the passengers. - I was amazed when I read
that, to tell you the truth. And I was amazed that a
person would intentionally make a rough flight to make people mad, because, what good does that do? This guy, from what I understand, he did it because he wanted
to punish the airline. - [Narrator] As more and more details about the captain's personality emerge, investigators are forced to
consider a troubling question. - Could his anger somehow
have caused this crash? - The morning after the
crash, a blackened scar on a frozen field marks
the fatal impact zone of Flight 3272. A team from the National
Transportation and Safety Board is already at work, recovering pieces of
wreckage for analysis. Investigators head to
Detroit Metropolitan Airport. They wanna hear from
the last person to speak with the pilots, the approach controller. - He was coming on rush hour. We had winter weather. - From air traffic control, we learned that the weather was bad and airplanes were starting to pile up on their approach into Detroit. - I made sure there was plenty
of distance between them. - There were other airplanes
on approach to Detroit. So sometimes when they're
in close proximity, there can be an issue with wake vortex coming off one airplane
that may affect another. - [Narrator] A wake vortex
is a horizontal tornado that trails behind an aircraft. If one plane flies too close
to the wake of another, it can encounter sudden
and extreme turbulence. - So, here's the Airbus American
West Airlines Flight 50. - [Narrator] The Airbus is almost twice the size of the Embraer 120. A wake vortex incident seems possible. But investigators won't know for certain until experts at NASA
analyze the radar data. (dramatic music) - And that settles that. - [Narrator] But it's another dead end. - It wasn't a wake vortex. - [Narrator] The analysis
reveals that the wake from American Airlines Flight
50 could not have dropped to the altitude of Comair 3272. Investigators are back where they started. Why 29 people died just
minutes before landing is still a mystery. NTSB system specialist, John DeLisi faces one of the biggest
challenges of his career. - We knew the airplane was
on approach into Detroit and something dramatic happened. Something went wrong suddenly. - What a mess! - [Narrator] The NTSB's Richard Rodriguez leads the investigation. - Our mission is to find
the cause of an accident, make recommendations that will prevent it from ever happening again. - [Narrator] He's very familiar
with this type of plane, having investigated previous accidents involving the Embraer 120. - The Embraer 120 propeller
blade had separated due to a fatigue crack over in an accident earlier in Georgia, and the
crew was able to land it but it was very difficult to control. - [Narrator] In two previous cases, part of a propeller blade
broke off in mid-flight. Could it have happened again? Rodriguez reviews details of where the two propellers were found at the Detroit crash site. He makes a troubling discovery. Part of one blade ended up 75 feet away from the main impact crater. He can't help but wonder,
is this the third time he's seen an Embraer 120 propeller fail? - We need to take a look
at those propeller blades. - We wanted to get those
blades of the propeller to ensure they were intact at impact. (dramatic music) - [Narrator] Rodriguez
studies the blade fragment, looking for evidence of failure. If the propeller blades were all attached and spinning at impact, they
would have all hit the ground with tremendous force, resulting in distinctive
damage on every blade. - This is impact damage. It was spinning right to the end. - [Narrator] The analysis leaves no doubt. Though the propellers fragmented
when they hit the ground, they did not fail in flight. Air China Flight 129 has been in the air for a little less than two hours. Among the 155 passengers is
a group of Korean tourists flying home from vacation. Their tour guide is
28-year-old, Seol Ik-Soo. (speaking in foreign language) - [Translator] I had
just started a new job and my wife was four months pregnant. There were about 20 people
traveling with our agency. I had many things to take care of. - I just can't believe that happened. (speaking in foreign language) - [Translator] I was working very hard because I had ambitions to be promoted. I didn't take breaks and worked late. I was trying my best. - [Narrator] But for Seol Ik-Soo who's trying to make a good impression at his new job, today is
feeling like a disaster. - I mean, what kind of person does that? - [Narrator] It all started
to go wrong this morning when he made a mistake that he
worries could get him fired. - [Translator] I had
arranged for the group to sit in first class, but right before we got to the airport, I realized that I'd
left my passport and bag in the hotel lobby. The bus driver had to turn around and go back to the hotel. (speaking in foreign language) The good seats were
first come, first serve. Because we had to return to the hotel, my group was pushed to seats
at the very back of the plane. - [Narrator] Seol Ik-Soo
has no way of knowing the far more important
impact of this minor mistake. - Ladies and gentlemen, we're
about to begin our approach to Gimhae Airport. Local weather is foggy with some rain. We'll be landing in
approximately 20 minutes. - [Narrator] Changing weather conditions are posing a challenge for the crew. - We're to land runway 18. Reduce speed. - Okay. - [Narrator] Seol Ik-Soo worries that the bad weather will
delay their arrival in Busan. (plane beeping) - Man, turn around. Pull up! Pull up! (speaking in foreign language) - [Translator] I heard people screaming. I was sliding. I couldn't keep my body straight because the speed was too fast. Then... Bang! (plane crashes) - [Narrator] Air China Flight 129 has crashed into the side of Mount Dotdae, miles from the intended runway. Of the 166 people on board, 37 survive. Almost all those who made it out alive were seated near tour guide, Seol Ik-Soo. - 90% of the tour group I
was traveling with survived. - [Narrator] The fact
that the young tour guide forgot his passport, something he thought was a shameful mistake,
will be remembered forever as a life-saving stroke of luck. Air China Flight 129 has crashed into the side of Mount Dotdae, miles from the intended runway. After any plane crash near a runway, some of the first people
investigators wanna speak to are the air traffic controllers. - It was slated to perform
a straight in approach, but it was changed to a circling approach. - Why the sudden change? - The wind changed direction. I changed the approach so
they can land into the wind. - [Narrator] Switching from a straight in to a circling approach is
something that happens routinely at airports around the world. - Some airports, you
have to come one way in because of mountains or whatever. And then once you get to the airport, because of winds, you may circle and land. - [Narrator] Flight 129
was originally scheduled to land on runway 36 left
coming in from the south. But after the change, they were
headed for runway 18 right, coming in from the north instead. - We're closer to the sea. The weather's always changing. We do this all the time. (speaking in foreign language) - [Translator] Air traffic
control gave them clearance for a circling approach,
which was appropriate for the weather conditions at the time. - Is there anything else you can remember? - Communications. Their radio communications were all wrong. - How do you mean? - Air China 129, contact
tower 118.1, circle west. - [Narrator] Shortly after
he instructs Flight 129 to do a circling approach, the tower controller tells the pilot to switch to a new radio frequency. - Air China 129, contact tower 118, one. - [Narrator] All airports
use a standard frequency to communicate in emergency situations. If air traffic control even suspects a plane is in distress, they will use this frequency
to contact the crew. - [Flight Officer] Gimhae
tower, Air China 129. Circle approach, 18 right. - Air China 129, check wheels down. Wind 210 at 17 knots. Clear to land runway 18 right? They finally called me back. It seemed like we're
finally back on track. Then less than a minute later, they crushed into the mountain. - [Narrator] The Air China
crew was slow to respond to air traffic control. Investigators need to know what
was going on in the cockpit during the unusual delay. - If air traffic controllers
make a statement, and the crew either doesn't answer or misinterprets it, it
can cause the accident. - [Narrator] Garuda Indonesia Flight 152 left the Indonesian capital of Jakarta nearly 90 minutes ago. Headed Northwest, it's expected to arrive at its destination in about half an hour. - [Air Controller] Surface winds, calm. Visibility, 400 meters. Present weather, smoke. - [Narrator] Forest fires in Sumatra have sent a thick blanket of smoke across all of Southeast Asia. - Indonesia 152, turn right heading 046. - Turn right heading 046, Indonesia 152. - [Narrator] Any second now,
the controller expects to see Flight 152 turn onto final approach. (menacing music) - What? - [Narrator] The Airbus has
somehow become dangerously close to the ground. - Come on! Climb! Climb! Climb! Go, go, go, go! Go! (plane crashes) - [Narrator] Investigators
gather information from the air traffic controller, the last person to have
communicated with Flight 152. - They approached from the southeast. I was trying to bring them in this way. Left turn and a right turn
that gets them into runway 05. - [Narrator] The controller suspects the captain somehow
misinterpreted his instructions and missed the final turn. With no sign of the black boxes, investigators gather
air traffic recordings made in the tower. It's hoped they can shed some light on why the plane turned
away from the airport instead of towards it. - Roll tape. - [Pilot] Confirming
descent to flight level 140. - [Narrator] The air traffic recordings capture only the radio calls between the pilots and the controller. - [Air Controller] Indonesia 152, descend to 3000 feet for runway 05. - [Narrator] They're not as
helpful as a CVR recording, which would reveal all sounds and conversation inside the cockpit. - [Air Controller] Reduce speed, 220. - [Narrator] But investigators
listen closely for any clue as to why the A300 veered
so badly off course. - [Pilot] On heading 215, Indonesia 152. - That puts them about
here, right on course. One more right turn and he's lined up with the runway. - [Air Controller] Indonesia 152, turn right heading 046. - There it is, clear as day. - [Pilot] Turn right heading 046, Indonesia 152. - Okay, stop there. They definitely understood, turn right. - [Narrator] How the flight
went so horribly wrong in the final few moments is baffling. - It's in the exact opposite direction they were told. - [Narrator] Investigators need the CVR if they hope to figure
out what exactly went on in the cockpit of Flight 152. The crash of USAir Flight 1016 is the first accident
involving a major airline in North Carolina in 20 years. Both pilots and the
cabin crew have survived. But of the 52 passengers, 37 are dead. Greg Feith, senior investigator with the National
Transportation Safety Board, will lead the investigation. - Any time you go to an
airplane accident site, a crash site, there's
always this wave of emotion. I don't care how seasoned
an investigator you are, because you know that people
have been seriously injured or killed in that particular event. - [Narrator] Examining the wreckage is the team's first task. - So what have we got? - [Narrator] They must determine
if a loss of engine power was a factor in the crash. They examine the DC-9s two
Pratt & Whitney power plants. Right away, they spot
something unexpected. - Oh, look at that. The thrust reverser on
this engine is deployed. - Their examination of
the right engine indicated that the thrust reverser was
in the deployed position, and that the thrust
reverser on the left engine was in the stowed position. - [Narrator] Thrust reversers
are deployed upon landing to help slow the plane down. They work by redirecting the engine's high powered exhaust gases forward. - If it happens in flight,
that's detrimental. Because if it happens on one engine in a multi-engine airplane, you create an asymmetrical
thrust situation. - Maybe that's what
brought this flight down. - We've had thrust
reversers deploy in flight. And depending on the
speed of the aircraft, you can literally break that
engine right off the aircraft. - [Narrator] Closer investigation
reveals abrasion marks on the metal of the right side reverser. Marks that suggest a heavy
impact with the ground. It's an important clue. Further analysis leads
to a definitive answer. Investigators know exactly when and how the right side reverser opened. - They were able to make a determination that the reverser on that right engine, even though it was deployed, happened during the course of the impact sequence and did not happen in flight. - At least we know it
wasn't thrust reversers. - [Narrator] Eliminating
one potential cause is a step forward for investigators. But there's still a long
way from understanding what brought down USAir Flight 1016. Investigators need to understand why air traffic control in Charlotte didn't warn USAir Flight 1016 about a fierce storm over the airport. - Oh, hey.
- Hey. - Good to meet you. - The air traffic controllers
had more information and they could see and they had been
watching this thunderstorm for much longer than the flight crew had. So we knew very early on, was gonna be one of the central areas
of focus to understand it. - Why did you tell the pilots the weather was good enough to land in? - The weather reports told us it was. - [Narrator] The controller
reveals that he relied on a bulletin from the
National Weather Service. It showed that conditions
were well within limits for a safe landing. - I even asked the pilot who landed four minutes
earlier how it was. USAir 983, how was the ride
in your final approach? - [Pilot] Smooth, USAir 93. - USAir 1016, previous flight
just exited the runway. He said it was a smooth ride. (soft music) It was fine. No problems. - [Narrator] The weather
bulletin issued at 6:36 p.m. was indeed correct. Conditions were clear to land. But minutes later, the skies
over the airport opened up and heavy rain poured down. - By the time I got to the next bulletin, it was too late. - Listen, I really appreciate your help. If I have more questions, is
it all right if I call you? All right? Thanks.
- Sure. - [Narrator] It's now
clear to investigators that weather conditions
at the Charlotte Airport changed very quickly. What's unclear is why the
controller's weather report failed to forecast the change. - See what we have here. - [Narrator] They studied the reports that the National Weather Service issued for Charlotte Airport that day. 6:36 p.m. Light rain showers. 6:40 p.m., heavy rain showers. It seems the weather
service correctly identified the change in conditions, but then investigators make
an important discovery. It took two minutes
for the weather service to transmit the new information
in an updated bulletin. - The problem came from
the air traffic controllers not having a full body of information from the National Weather Service. - Flaps 40 please. - So, they weren't providing
real time information to the flight crew. - [Narrator] Weather
radar images soon lead to another discovery. - This is crazy. Look at that. There are two storm cells moving in here. - [Narrator] As the USAir
pilots were trying to avoid one storm formation... - 1840. - [Narrator] Another storm cell... - [Investigator] 1842. - [Narrator] Suddenly
increased in intensity. - They were blindsided - Here come the wipers. - [Narrator] The late weather report left the crew unprepared
for the sudden downpour. The critical question now, was the rainstorm strong enough to knock Flight 1016 out of the sky? Salvage crews pull what
remains of TransAsia Flight 235 from the Keelung River. (menacing music) There's no telling which piece of wreckage might hold an important clue. Investigators wonder if
the flight control system shows any sign of a malfunction. - Nothing wrong with this actuator. - We cannot find anything
wrong with the actuator, the linkage of the control. - Control system seems fine. - [Narrator] A search for
any pre-impact failures in the plane's hydraulic
system also comes up empty. - Nothing wrong with the hydraulics. Is this the left engine? - Yes. - [Narrator] Investigators
know from the dash cam video that the plane was banked
steeply to the left. A mechanical fault with the left engine seems like the next most obvious suspect. - We need to take a look inside. Get the borescope. (speaking in foreign language) - [Translator] From a
borescope examination, we can see whether or not
the compressor and turbine are damaged on the inside. Since the turbine rotates
with extremely high speed, if it is even slightly damaged, it will be completely destroyed. (soft music) - [Narrator] But the borescope examination yields no new clues. - Left engine completely operational. Strange. - [Narrator] They need to
explore other possibilities. - What about the right engine? Let's go take a look. (dramatic music) - [Narrator] They study the right engine and what they find is mystifying. - Look at the blades. They're feathered. - [Narrator] Feathered is a
propeller's fail-safe position. When a propeller engine
loses power in flight, the blades automatically rotate parallel to the airstream to reduce drag. The discovery only deepens the mystery. - Why would the right engine be feathered, when the dash cam video clearly shows the plane banking to the left? - It doesn't make any sense. Let's have a look. - When we discover a
feather of the propeller, we know there should be
something wrong about the engine. - Anything? - Nothing at all. (speaking in foreign language) - [Translator] Both engines
yielded normal results after examination. They were both fine. - There's nothing wrong
with this engine either. - If both engines were operational, or why did this plane crash? - [Narrator] It's just before 6:00 a.m. at Sharm El Sheikh Airport in Egypt. 217 passengers are headed
to St. Petersburg, Russia, some four hours away. At 5:51 a.m., Metrojet Flight
9268 lifts into the air. - [Man] The aircraft took
off in a standard way. No problems with the takeoff. - [Narrator] Flight 9268
reaches cruising altitude, 31,000 feet above the Sinai Peninsula. All is going smoothly
at air traffic control until 6:13 a.m., when Flight 9268 does something unexpected. The Airbus seems to be dropping. - Metrojet 9268, are you
experiencing any difficulties? Do you read me, Metrojet 9268? - Then all of a sudden,
everything just dropped off at the altitude, just
dropped and disappeared. - Do you read me? - [Narrator] As rescuers
arrive on the scene, it soon becomes clear that
there are no survivors. - Airbus aircraft just simply
do not fall out of the sky. So that gets everyone's,
their ears perked up on what happened here? - Really? - [Narrator] There are rumors this was a terrorist attack.
- I'll be right there. Take a look at this. - [Narrator] A terrorist group affiliated with Islamic State,
fighting to seize territory across the Middle East,
claims responsibility for bringing down Metrojet 9268. They say it was in retaliation for Russian military attacks in Syria. Though there is no proof
to back up the claim, there's speculation that attackers used a surface to air missile. - When I looked at the debris field, I kept thinking, right again. Another catastrophic, shocking crash as a result of an ignition
device hitting the aircraft. - [Narrator] After the
fall of Libyan leader, Muammar Gaddafi in 2011, militants raided his weapons depots, flooding the region with Russian made shoulder mounted missile launchers. Investigators need to
know if those weapons are powerful enough to hit an airliner at cruising altitude. - These are the missiles they're using. Plane was flying at 31,000 feet. What's the range on those missiles? - I was just looking at the specs. Check it out. - [Narrator] They study military documents and make some quick calculations. They soon have their answer. - It's not possible. Not with the weapons they have. - It was too of an altitude to
be a surface to air missile. There was good reason for
people to speculate initially that this could have been
a surface to air missile. That group has used a surface
to air missile before, specifically in early 2014
to shoot down successfully an Egyptian helicopter. - The first officers
was being interviewed. (speaking in foreign language) - What's she saying? I
can't understand a word. - They spoke with the father just before he flew
out of Sharm El Sheikh. - And what did he say? - He said there were mechanical
issues with the plane. - I did see reports of
family members quoting that safety was dubious on this aircraft. - There's only one way to find out. - The fact that the
aircraft might have had a lot of problems, you'd
have to firstly find out what those problems were. And secondly, are they relevant to what we know has happened? (menacing music) - Excuse me. - [Narrator] Investigators
speak with the aircraft engineer who last serviced the airplane
in Sharm El Sheikh Airport. - What can you tell us
about Metrojet 9268? - We serviced it for 30
minutes before takeoff. - Doesn't sound like a long time. - That is a quick turnaround, and low-cost carriers
sometimes have to do that. - They work their people hard to turn the aircraft round fast, so that that aircraft is in the air as many hours of the day
as it possibly can be, earning money for them. - [Narrator] The aircraft
was 18 years old. It had been through
several different owners. But maintenance engineers insist that the plane was mechanically sound. (plane engine roaring) - Significant incidents maybe in the past, something like that? - It had a tail strike in 2001? - [Narrator] A tail strike
is when the rear fuselage of a plane hits the runway
during takeoff or landing. Damage can be minor or severe, depending on the force of the impact. Maintenance records show that the tail strike damage was repaired. Investigators now wonder
if a tail strike repair from 14 years ago may
have fatally weakened the Metrojet Airbus. The shattered remains of Metrojet 9268 have been moved from the Sinai Desert to a massive warehouse in Cairo. - Let me take a look at this. - [Narrator] Investigators
hope the collected debris can tell them if an
improper tail strike repair from years ago doomed
Metrojet Flight 9268. They sword through tail pieces
from the Metrojet Airbus. They focus on the ones that were repaired because of the tail strike incident. (dramatic music) - If any mistakes or shortcuts
are made during the repair, then that tends to put
abnormal or uneven stresses on various parts of the metal structure. And that starts the
process of metal fatigue and you get cracks. - Fatigue has certainly,
to trained investigator, has quite distinctive characteristics. - No signs of damage around the repair. - Something else caused it. - [Narrator] Before long, they also rule out engine failure and all other mechanical failures. It seems there was nothing
wrong with the aircraft. - Just doesn't make sense. - [Narrator] It's been almost 48 hours since Thai Airways Flight 311 disappeared in the Himalayas. Investigators have yet
to find the aircraft. But now they're about to
get an important break. Local villagers report that they found aircraft
debris north of Kathmandu. The reported crash site is nowhere near the area they've been searching. - I don't think they ever
in their wildest imagination thought the airplane was
north of the airport. - [Narrator] North of Kathmandu,
near the border with Tibet, the Himalayan peak soared to
an altitude of 20,000 feet. These Northern summits are the reason almost all planes
approach Tribhuvan Airport from the south, where the mountains are closer to 8,000 feet. (chopper whirring) Later that day, 27 miles
north of Kathmandu, search crews find the remains of Thai Airways Flight 311. The point of impact is a steep rock phase more than 11,000 feet up the
side of a remote mountain. None of the 113 people
on board have survived. The challenge for investigators is unlike anything they've
encountered before. The terrain is so extreme,
helicopters can't land near the impact zone. The team will have to trek
more than 3000 feet up from the base camp to reach the wreckage. It's a treacherous five-hour hike. The team includes experts
from around the world, including Canada's David Rohrer. - The level of destruction was enormous. You couldn't tell that you had an Airbus 8310 aircraft there. I mean, you couldn't even
tell you had two engines. (gentle music) - The first big question they have is how did Thai Airways
Flight 311 end up here? The Airbus should never have been flying north of the airport. - Right over there. - [Narrator] An airport
hangar in Kathmandu is the final stop on a long journey for wreckage collected
from the mountain side. - The sherpas would bring down the pieces that we identified down
to the landing zone. And then the Nepalese
army and their helicopters would put them in nets
and then sling them down to the hangar at the airport. - [Narrator] As team members
comb through the wreckage, the investigation takes
an unexpected turn. (soft music) - Excuse me. Can I help you? - During the investigation, one of the family members was asking for a circuit board, just because they somehow would link them to their loved one. - [Narrator] The unusual request leads to an incredible find. - That's when we actually
found the internal mechanism of the recorder we were missing,
which was quite amazing. - [Narrator] The FDR
should provide crucial data on the plane speed, direction and altitude throughout the flight. - You always hope that
luck is on your side, that things will happen to your benefit. And those are the kinds of moments you really hope for as an investigator. - [Narrator] It's the breakthrough
they've been waiting for. Evidence that could
reveal how a plane flying south of the airport ended
up slamming into mountains to its north. (soft music)
