Original subtitles

narrator: the fatal crash of delta airlines flight 191

to support fujita's theory.

as the airplane approaches the rain column,

a downdraft hits the airplane, which pushes it down,

causing it to instantly lose airspeed and crash.

traditionally, pilots are alerted to these situations

because they can see the rain column ahead of them.

but sometimes the cool air columns can be invisible.

hinton: one of the very dangerous aspects of microbursts,

particularly in the high plains region of the country,

for all this precipitation is that it's possible

to evaporate before it reaches the surface.

that's particularly dangerous because there's no visible rain.

the pilot may see clear skies, a clear path, but there could be

a very dangerous microburst in front of the aircraft.

finally provides the missing evidence

forces the aviation community to immediately push for research

into new technology

that could warn pilots of microbursts in the area.

the solution is a radar beam

that detects changes in wind speed and direction

that is now installed in the nose

of every commercial aircraft.

it gives the cockpit crew a warning

before entering a microburst.

hinton: so this is a radar system.

the transmitter that generates essentially the microwave energy

the aircraft that's going to exit

is sending it through a wave guide

down through this system and back out to the radome,

setting off a deafening explosion.

and can last between 5 to 15 minutes.

fujita suggests that these downdrafts

could be to blame for a series of airplane crashes.

hinton: a downdraft is basically air flowing downward.

and it can also be the microburst,

which was the killer type of downdraft

for transport aircraft for many years,

which is induced by precipitation.

narrator: the idea is hotly disputed for the best part of a decade

until, on august 2, 1985, tragedy strikes.

in the midst of a thunderstorm, delta flight 191 descends

towards dallas-fort worth international airport.

less than a mile from the runway,

the jet inexplicably plummets into two water tanks,

which is then steered left, right or up or down

137 people die.

20 more sustain serious injuries.

[sirens]

as nasa engineer david hinton explains,

the crash turns out to be

one of the most significant in aviation history.

hinton: delta 191 was a very important event,

a very tragic event,

and it occurred just as the federal aviation administration,

national aeronautics and space administration,

the airline industry was beginning a program to solve,

tackle and solve this problem.

narrator: but delta airlines flight 191

under clear skies.

as to what the wind is doing it's simply not available

at that moment in that location.

narrator: in rainstorms, downdrafts and microbursts

can be potentially fatal.

but on the day steve fossett disappears,

there are no storms.

could there be something unique

about the mountainous region of the sierra nevada

that creates a similar effect?

the downdraft that brought down the delta airlines flight

happened in the middle of a storm

and on perfectly flat terrain.

but steve fossett has crashed

into the high mountains of the sierra nevada

perfect information; doesn't have

the question is can these microbursts strike without rain?

the first clue that they might dates from 1933

when two german glider pilots make an extraordinary discovery.

when hans deutschmann and wolf hirth

glide next to a mountain range in germany,

they discover that when a mountain drops away

to a hot plain,

there is a surprising phenomenon.

when winds blow into the mountain,

the air is pushed up and over the peak.

the cool air drops quickly towards the ground.

in the punishing heat of the plains

surrounding the sierra nevadas,

the air is rapidly heated and rises back up.

there were people who thought it might not be feasible

to project the radar beam where we would like it to go.

then a reflected beam is picked up by the same antenna.

so they transmit, listen, transmit, listen;

it's a pulse system.

picked up again by the signal, by the radome

through the wave guide back into a receiver.

narrator: but many in the aviation community

are possible. don't think these radar systems

hinton: delta 191, as tragic as it was,

led to a tremendous urgency

to develop the solutions to the problem.

at the time of that accident

this system for wind shear detection

was simply not available.

it can hit the ground and spread out in all directions,

to put in a small radome,

all the processing and the quality of the beam

required to extract the wind shear.

this program developed these radars

that are now installed,

so the problem has been solved

because of the urgency with which the faa, nasa,

the airlines and others put into developing this solution.

narrator: but even with this new technology installed,

pilots still have to remain vigilant.

hinton: one cannot be certain

about the currents over a mountain.

the pilot of an aircraft

but this doesn't stand out to me

into the twilight zone. like you're going

relatively benign conditions you're, you're going from

to unexpectedly not so benign conditions,

and this is in the dark.

[thunder]

narrator: kelly redmond now examines weather data

for september 3, 2007: the day steve fossett disappeared.

could he have been trapped in similarly disastrous conditions?

looking at here is a map redmond: what i'm

of what the conditions were on september 3rd of 2007.

september is not a month of very strong storms, typically.

and they show that the flow, uh, over the sierra nevada

was moderate winds out of the southwest

to the, to the northeast.

you know, you sort of feel

as being particularly strikingly strong

like you see in the winter months.

narrator: the weather data shows that steve fossett

taxied down the runway on a clear day.

other pilots flying that day

also reported that it was a beautiful day to fly.

but even on clear days,

small meteorological anomalies can strike.

kelly finds new significant evidence

in the weather data for that day.

redmond: there was a little hitch in the wind direction,

which sort of indicates that a little impulse

might have been moving through in the atmosphere.

the kind of thing you normally wouldn't catch

narrator: the archive is also a critical tool

tolby: some weather is more predictable than others.

we knew today that there was going to be thunderstorms

in the area.

where exactly those are going to be at any one point

is really challenging.

narrator: could these unpredictable storms

be behind some of the hundreds of plane crashes

in the sierra nevadas?

at the nevada desert research institute,

climatologist dr. kelly redmond has access to 60 years

of historical weather data for the united states.

kelly redmond: we store weather and climate data from the past

because it turns out it has tremendous value.

the past is, is a guide for the future.

much attention to. or wouldn't pay

for air crash investigators.

it can reveal local weather conditions at the precise time

some of the most famous disappearances occurred.

kelly locates the weather data for february 18, 1969,

crashed. the day the gambler's special

he discovers that it's highly likely

that the weather played a critical role in the disaster.

redmond: so these darks colors here are 70, 80, 90% humidity.

so this means that the clouds

were probably pretty prevalent at the time,

and once they got into 'em it'd be pretty hard to get,

to get back out of them.

[wind howling]

doing is, uh, trying to pinpoint theodore fujita: what i'm really

and they create a wave cloud,

um, beneath that the winds can get really turbulent,

and those kind of winds

are really, really challenging to predict.

narrator: most of us have experienced turbulence during air flights.

but most aircraft navigate through these winds

without any serious problems.

but in 1977 a meteorologist, dr. theodore fujita,

proposes a previously unknown weather phenomenon

that he thinks might transform bad weather

into something potentially deadly.

fujita is known as "mr. tornado"

for his work on the detailed behavior of twisters.

announcer: aeronautics and space report.

tolby: when the really strong winds come over the sierra

which particular thunderstorms might produce tornadoes.

with tornadoes reveals narrator: fujita's work

that when hot and cold air are mixed in a rainstorm,

intense, localized downdrafts can be caused

by the rapidly cooling air.

david hinton: what theodore fujita found

from flying small planes in areas

that had been hit by tornadoes and severe storms,

he found patterns in blown-down trees

that were not appropriate for a tornado.

so he coined the term "microburst."

microburst downdraft.

narrator: fujita's theory is

that when rain-cooled air sinks suddenly,

we send up a balloon twice a day;

this seems to me a kind of a typical thing

that happens in mountains,

where weather can change very dramatically, very suddenly,

especially in the lee of a large range

like the sierra nevada

where there was, uh, a wind system

coming through at the time.

narrator: such localized changes in wind direction

are invisible to the naked eye, but they can be lethal.

meteorologist zach tolby knows all too well

about erratic localized wind conditions

in the sierra nevada.

tolby: are we clear for a balloon launch?

okay, thanks. bye.

as the warm air hits the cooler air at high altitude,

once at 4 a.m. and once at 4 p.m.

we do this along with about 800 other sites worldwide

and about 90 sites around the united states and north america.

narrator: these regular readings help to calculate the weather forecast.

key to their accuracy

is the behavior of wind in the upper atmosphere.

tolby: the measurements from the balloon

tell us a lot about wind.

they actually physically measure the wind with a gps.

narrator: the balloon data reveals that wind speed and direction

can vary considerably at different altitudes.

at the boundaries between these different layers,

the wind can interact in very unexpected ways.

of climbing at 300 feet per minute.

the national transportation safety board concludes

that a downdraft was responsible

inexplicable loss of control. for steve fossett's otherwise

how else could a pilot

who routinely calculated the dangers of the wind

fall prey to it?

flight instructor bill schroeder

final report. agrees with investigation's

in the sierra nevadas, winds can rush down

at 400 feet per minute or more

and then bounce back up again even faster.

schroeder: he was in a 400, 500 foot per minute, possibly more.

his aircraft was only capable,

at that density altitude where he was flying,

after a five-month investigation,

so he didn't have the power.

he could not get out of the downdraft.

narrator: while filming, bill's plane is suddenly hit

by an invisible downdraft.

to get a li... schroeder: see, we're starting

oh, probably a 200, 300 foot per minute downdraft here,

right at this location here.

narrator: today bill is high enough to ride out the downdraft--

but at lower altitudes, closer to the mountain ridge,

even the most experienced pilots

will struggle with the rapid loss of speed.

up here just a little bit. schroeder: i'm going to climb

and paying close attention to it all i'm doing is i'm aware of it

and getting myself into a position

and trying to keep the plane aloft--

to actually visualize what's happening.

narrator: the model aircraft is being flown

by a member of the facility.

to prevent the airplane from crashing,

it is held loosely in position by restraining wires.

the remote pilot is having no problems

flying through headwinds

modified to approximate the conditions

steve fossett had been flying in.

when a powerful wind suddenly, there's trouble

starts battering the airplane, and the pilot loses control.

mathers: we can certainly see in this particular experiment

that the plane was not able to overcome downward velocity.

so even though we had a pilot operating the controls

where if i should have to turn,

using as much climb rate as possible--

he was still not able to overcome

and was still dropping in altitude.

narrator: by slowing down the footage

we see how the plane engine isn't powerful enough

to overcome the wind forcing it towards the ground.

the forces recreated here are no greater

than those possibly faced by steve fossett.

steve fossett was a skilled pilot

who broke more than 100 aviation records around the world.

but he crashed flying his airplane

in the sierra nevada mountains,

a place he knew like the back of his hand.

who have crashed in the sierra nevadas,

knowing the likely cause

is cold comfort to surviving relatives,

like william ogle,

whose father disappeared over the sierra nevada ridge.

for 40 years, ogle: i've been dealing with it

and they may not find his wreck,

to deal with it. and i'll continue

but that's just something that i've accepted.

narrator: the nevada triangle has been home

to thousands of lost airplanes over the last 60 years.

the missing evidence concludes

that some of the airplane crashes

can be attributed to the testing of military airplanes.

but for steve fossett and hundreds of other pilots

narrator: but until all the missing aircraft are discovered,

the culprit is mother nature herself.

and although technological advances

have made flying safer than ever,

the sierra nevadas will always pose a threat

to those who fly through them.

schroeder: you really have to treat the winds in the mountains

with respect.

narrator: the winds in these mountains don't discriminate

between the most experienced pilot and the novice.

schroeder: regardless of how professional,

how much training, how much experience a pilot has,

they can still get in trouble.

and so we have to be very vigilant when we're flying,

especially here in the mountains.

the head of the civil air patrol came and sought me out.

the left toward lower terrain. i'm going to be turning to

narrator: steve fossett was no stranger to these downdrafts.

but on that particular day, he was flying too low

and too close to the mountains,

and that was a deadly miscalculation.

downdrafts also explain the mysterious force

that came out of the blue

and so nearly took the lives of jim nowlin and his passengers.

is pushing on you nowlin: it's almost like a hand

and stealing away your airspeed.

in spite of all the hours i'd spent flying

over and around the sierra,

uh, i had never encountered that kind of a downdraft.

i probably used up 99% of my luck in that one time.

smoke within the airflow we're going to try today to use

in search and rescue and he's been involved

for i think he said 45 years,

and he said he wanted to shake my hand

because it was the first chance he ever got to do that,

to shake the hand of someone who'd gone down

in the sierra like that.

that anything ever happened. it's the only trace

till now, and i, i haven't touched it

this probably came off but it's, uh, i would say

one of the, uh, wingtip moldings.

and, uh, yeah, this is the only sign

that anything ever happened here.

no sense leaving it here. [laughs]

but for airplanes they can be treacherous.

there's a nice little bump.

parallel to the mountains; there's that line of clouds

about a quarter of the distance we're gonna get

between the top of the mountain and the middle of the cloud.

where the best lift will be. that'll be the,

the area underneath these clouds;

there can be a rotor,

it can be really turbulent getting up into it,

and if we get up above those clouds

and get into the actual wave, it'll be very smooth,

very smooth conditions, just no turbulence at all.

feels like you're not moving.

narrator: for a glider, mountain waves

offer the thrill of extreme sport.

to be able to use it for your advantage.

holtz: power pilots may not fly in these conditions

just because they have not experienced them.

in this much wind. they're not used to flying

narrator: and the winds closest to the mountains

can be the most lethal for airplanes.

to better understand the mountain wave,

climatologist kelly redmond explains

that we first need to understand

unique topography. the sierra nevada's

redmond: one factor about the sierra is they,

they come up gradually on the west side

and they drop very steeply on the east side.

and so when the air is climbing the slope on the west side,

at a fairly gentle slope. it's kind of climbing at a,

so you... some of it's moving up and down,

the process is repeated,

creating waves of hot and cold air.

as a glider pilot, russell holtz

regularly seeks out this strange phenomenon

in the sierra nevadas, known as a "mountain wave."

russell holtz: this area is, has some of the best weather,

best conditions for soaring.

we can get really high, we can go really far.

narrator: some gliders, like russell's, have no engines,

so they need a tow plane to reach the right altitude.

then they are released.

once set free they rely purely on the rising wind currents

to keep them up.

holtz: almost always the air's in motion,

and then it has an abrupt break that's shaped like this.

if a glider stays in the, uh, up part,

in the air that's moving up,

then we can stay up indefinitely.

same thing you see birds doing.

narrator: in clear skies, currents are invisible,

so glider pilots have to be extremely aware

of their surroundings.

holtz: and all the data you're gathering--

via clouds, your wind drift, what you're feeling,

what the instruments are saying,

so all that you try to put into a mental model

of what the air is doing...

the more you know about the safer it is

with the almost identical power-to-weight ratio.

we're using the facility

in a way that we never envisioned before.

narrator: andrew mathers and his team have rigged up a replica

inside the wind tunnel. of steve fossett's plane

a remote-controlled aircraft; mathers: it's

it's actually 1/8 scale.

uh, it has almost the same physical properties

as the super decathlon

that steve fossett was flying at the time.

um, it has very similar scale model wing span length.

the fuselage is hung underneath it's a high wing design, so

so that gives it similar center of gravity,

similar flying properties.

a single-prop aircraft as well it's

doing something a little unique. andrew mathers: but today we're

narrator: they have studied the meteorological records

to recreate the precise wind speed and direction

in the region where steve fossett lost his life.

mathers: okay, fans coming up to 50%.

narrator: with 106 fans, each individually controlled,

the team are hoping to reproduce the effects

of the invisible and unpredictable downdrafts

that researchers now think make the nevada triangle so deadly.

mathers: achieve the flow that we wanted, we're configuring our fans to

which was a combination of forward flow

as well as downwash.

different combinations of fans uh, so we're using

to achieve what we want to.

and some of it comes over, and it comes down

it has an abrupt break where it can go downhill,

and this can cause lots of different wave phenomena

in the atmosphere.

narrator: studying the flow of water in a riverbed

can help visualize just how turbulent

these downhill winds can become.

redmond: if you think of that whole line

of, uh, rock underneath the water,

a mountain range. it's sort of like

there's not a lot going on

in the upstream side of the mountain.

but on the downstream side

is where most of the action is occurring.

we see different types of flow coming over,

but predicting where and when they occur is far from easy.

and it jumps up, and it gets very turbulent.

narrator: the river's downstream

is the mountain equivalent of a downdraft.

they occur below the crest of the mountain.

the winds accelerate as they come over the ridge,

clinging to the surface as they race down the slope.

are these powerful downdrafts, unique to the sierra nevadas,

responsible for steve fossett's crash

and hundreds of others in the nevada triangle?

scientists at the windeee dome,

hexagonal wind tunnel facility, the world's first

usually study the effects of wind on fixed structures

like buildings and bridges.

studying the sierra nevada phenomenon,

but at least the findings give hope

is more likely accidental. that ogle's disappearance

as the number of crashed airplanes

unearthed by fossett's manhunt

continues to grow alarmingly,

the press dub the area "the nevada triangle."

the news is no surprise

to aviation archaeologist pat macha.

pat macha: the nevada triangle, the name

came from the steve fossett search.

suddenly this element of mystery,

why can't we find him,

other wrecks in this area. oh, there's so many

narrator: pat macha has spent 50 years

doesn't match his father's airplane.

and he is not surprised by the comparison.

the bermuda triangle is infamous--

yet within it, there have only been about 30 unsolved cases

of aircraft or marine disappearances

since the late 1800s.

the so-called nevada triangle falls within an area

between three cities: reno, las vegas and fresno.

and within it there have been far more disappearances.

macha: there weren't dozens

but hundreds and hundreds of aircraft

over the years in the mountains.

if we marked all of the crash sites,

this map could not hold all the pins.

it would be so loaded you wouldn't believe it.

charles ogle, a businessman

by air and on foot.

and although they find no sign of steve fossett,

they do find plenty of evidence

that the skies above the sierra nevadas

could be treacherous.

schroeder: while we were searching for steve fossett,

we found several other aircraft that had crashed in the areas

that were reported missing,

but the planes had never been found.

families had gone for years and years

without knowing what happened to their relatives.

narrator: one of those family members is william ogle,

whose father charles disappeared 43 years earlier.

reporter: the year was 1964.

narrator: pat has documented more than 2,000 wrecks in the area.

and ex-military pilot from california,

flew a single-engine plane out of oakland headed for reno.

narrator: for decades, william and his family wondered--

did he abandon them, or was there an accident?

43 years on and the search for fossett's plane

raises the possibility that ogle

is also a victim of the sierra nevadas.

could one of the wrecks be his father's?

william ogle: it would be nice to sort of have the closure

so that you know that he didn't just run off.

i mean, an accident, something happened.

narrator: unfortunately it is bad news.

the plane's registration number

and was familiar with the terrain.

what is uncommon is that there were five lost

in the search for one.

the following summer narrator: it's not until

that the wreckage of the gambler's special

is discovered near mount whitney,

when the receding snow reveals the scale of the tragedy.

macha: the nature of this impact was terrible.

and the aircraft disintegrated.

narrator: the wreck is found on the east-facing cliff

on mount whitney.

there are no signs of mechanical or electrical malfunction.

the official investigation concludes

that the cause of the crash is bad visibility.

but like fossett, the pilot was vastly experienced

this is not uncommon, however.

one month after it starts,

plane is called off. the search for steve fossett's

schroeder: it was abandoned because of the fact

that we just had searched so long, so many areas,

covered these areas not just once, twice,

three or four times, and we weren't getting anything.

narrator: disappearance it seems that steve fossett's

will have to join the growing list of mysteries

within the nevada triangle.

the hunt to explain the staggering number of accidents

continues.

and just like the bermuda triangle,

the nevada triangle is generating

some extreme theories.

or early the next morning.

over the last 50 years,

every month. that's close to three crashes

yet it is only rarely

that these plane crashes attract headlines.

one of the exceptions

is the 1969 hawthorne nevada airlines flight 708,

the so-called gambler's special.

macha: the story of the gambler's special

is a very interesting case.

there was the hawthorne nevada airlines,

and they had two dc-3 aircraft, and they would fly routinely

from long beach to burbank to hawthorne, nevada.

and people could fly up there, they could party and gamble

and then fly back home late that night and,

narrator: for more than a month they comb the mountains

narrator: but on february 18, 1969,

the commercial airliner,

carrying 32 passengers and 3 crew members, disappears.

macha: radio contact was lost.

the aircraft did not arrive in, at burbank as scheduled.

so a search was immediately launched.

narrator: but the tragedy turns into a disaster

when five of the search aircraft also crash into the mountains.

the country is shaken by the rising death toll.

macha: the press, uh, really latched on to that story

because it was so interesting and compelling.

the search in the first place,

and then to lose so many searchers in the process.

a couple of things make it very special around here.

to discover the deadly truth

behind the area that has been dubbed "the nevada triangle."

the sierra nevada mountain range stretches 400 miles

across the state line between california and nevada.

most famous parks: it houses three of america's

yosemite, sequoia and kings canyon.

people from all over flock to enjoy the stunning scenery,

from the emerald green waters of lake tahoe

to the rugged forests.

but for thrill-seekers,

the most dramatic and compelling aspects of the sierra nevadas

are the skies above them.

bill schroeder: i started flying in the sierra nevadas

about 1970.

sophisticated wind chamber and in the world's most

number one, it's challenging,

and i think that pilots need to be challenged.

the other thing i like about flying here

is just the beauty of the area.

you know, you get up in the early morning

and come out here when it's nice and cool,

clear, visibility totally unlimited.

you can take a turn to the right,

take a turn to the left, and what do you have?

just beautiful mountains.

narrator: but on september 3, 2007,

the disappearance of a famous pilot

would throw a spotlight on the mountains' terrible secret.

reporter: aviation officials are looking for adventure pilot

man: while we were searching for steve fossett

one of the most beautiful and dramatic places in america.

a land of extremes--

from snow-covered mountain peaks to scorching deserts.

but these mountains hold a terrible secret.

is pushing on you man: it's almost like a hand

and stealing away your airspeed.

narrator: a mysterious force that has taken countless lives

over the past 60 years.

man: if we marked all of the crash sites,

this map could not hold all the pins.

[applause]

narrator: but it takes the disappearance

of billionaire steve fossett in 2007

before the extent of the mystery becomes clear.

and world record holder steve fossett.

we found several other aircraft that had crashed in the areas

that were reported missing, but the planes had never been found.

man: there are literally hundreds of plane crashes

in the surrounding area.

it's an intriguing mystery.

man: instruments fail, compasses go haywire,

and in the worst-case scenario

the ignitions of jet engines fail.

narrator: so why have so many pilots lost their lives

and others vanished without a trace?

and what is the missing evidence

that could explain the disappearances?

we explore the phenomenon on the ground, in the air,

to call in a flight plan-- that fossett doesn't even bother

for a civilian in peacetime america.

reporter: aircraft are continuing to criss-cross

over an area of about 17,000 square miles

of northwest nevada.

narrator: aviation safety expert bill schroeder

was one of the lead coordinators on the search.

he recalls how the terrain made their job incredibly tough.

to find aircraft schroeder: it's very difficult

that go into canyons, that go in between the trees.

to search. from the air it's really hard

narrator: when fossett says goodbye to his wife that morning,

he refers to his flight as "a sunday drive."

he takes off from a private airport 60 miles south of reno.

the sunday drive is so routine

the biggest and most expensive search ever undertaken

an error that will seriously hamper the search teams.

schroeder: a person of his stature in aviation--

tell somebody i don't know why he didn't

exactly where he was going to be going,

i really don't know.

narrator: with no idea of the direction fossett took,

the teams are forced to search over 30,000 square miles,

an area equivalent to the state of maryland.

schroeder: we had our air national guard involved

in the search as well,

to see if, uh, if they could find anything on the dry lakes.

we had other pilots, believe it or not,

that decided they were going to help,

and no one could find him.

i've wanted it for a long time.

narrator: billionaire adventurer steve fossett takes off

from a private airstrip

about 30 miles south of carson city, nevada,

in a single-engine airplane.

he never returns.

man: we are not going to rest

until we bring this to what we feel is a successful conclusion.

narrator: fossett is an experienced aviator

who lives to break aviation records.

in 2002 he becomes the first person

to fly solo across the world in a hot air balloon,

and a few years later,

he does the same in a single-engine aircraft.

steve fossett: so this is a prime record.

ufo enthusiast bill birnes

narrator: to commemorate the historic event,

both aircraft are housed

national air and space museum. at the smithsonian's

how could a man with more than 100 world flying records

to his name

disappear on a routine flight in his own back yard?

the mystery captures the attention of the world's media.

schroeder: i think it became a big story

because of the fact of his reputation.

reputation as an aviator, as an adventurer

that suddenly just disappeared,

kind of shocked the world. and i think that's what

narrator: fossett's disappearance triggers

where i could maneuver the airplane to some degree,

the ground rising quickly below him.

you know, nowlin: it's almost like,

a hand is pushing on you and stealing away your airspeed.

in aviation there are two things that are irreplaceable:

that's airspeed and altitude.

if you have the right combination of the two,

then you can handle most anything.

if you have one or the other taken away from you,

then you're in trouble.

i mean, it slowed me up so much

the airplane was no longer capable of flying.

the last thing i really remember was there's some tall trees

back behind us over there

i still had enough airspeed

but seconds later, he loses airspeed,

and i was bound and determined

i was going to stay out of those trees.

narrator: luckily for jim,

he and his passengers all survive without serious injuries

and are rescued within hours of the crash.

but could his experience cast light

on the fate of steve fossett?

in october 2008,

over a year after the search for fossett's plane is called off,

a hiker makes a discovery.

man: i said, "oh, my gosh, what's that?"

and in the dirt with the pine needles,

in the dirt i see like an i.d. card.

reporter: tonight at the command post,

jim nowlin's story is typical.

but of course makes no mention of any ufo-related research.

merlin: i think sometimes people prefer to believe the mystery.

literally tell me i've had people

that the more they learned

about what was actually going on at area 51,

the less interested they were.

narrator: military accidents can account

for a lot of the crashed aircraft

found in the vicinity of area 51--

for the crashes but they don't account

in the sierra nevada mountains.

most of the crashes and disappearances

in that area of the nevada triangle

are civilian aircraft.

officials are waiting for daybreak

on a sunny spring day in may 2013,

jim nowlin is taking his friends out for a ride in his airplane.

jim nowlin: my friend had set it up many weeks in advance

as a birthday present for his girlfriend

to do a tour around lake tahoe,

many of those. which i've done many,

most of my life, i'd been flying over the sierra

was going to be any issues. so i didn't really think there

well, when we took off it was bumpy--

nothing that i considered at all unsafe.

turbulence over the years. i've been in some pretty good

narrator: jim flies out of the mild turbulence

and back into calm weather conditions.

and a lot of times for us that's daytime heating,

at the national weather service in reno, nevada,

believes that the unpredictable weather conditions

over the mountains

are the key to unraveling the nevada mystery.

tolby: the sierra nevada is unique

to an ocean, because it's very close

and we get strong storms out of the eastern pacific

during the wintertime.

narrator: and when those storms hit the unusual geography

of the sierra nevadas,

the huge fluctuations in altitude and temperature

can intensify the storm.

tolby: the thunderstorms form

in the atmosphere, when there's instability

narrator: zach tolby, a meteorologist

which creates that instability,

and the cooler air up, up in the atmosphere,

and so as that warm air rises and then condenses,

it accelerates up.

narrator: with its peak soaring to over 14,000 feet above sea level,

mount whitney is the highest point in the u.s.a.

outside of alaska.

yet at the foot of the mountain lays death valley--

at 282 feet below sea level.

as the cool stormy air from the ocean

flows over the high mountain peaks,

it is met by the hot, humid air rising from death valley.

the combination causes sudden and intense storms.

[thunder]

whatever brought him down,

so that ground crews can try

to confirm the sightings from the air

of possible wreckage of an airplane,

probably the long lost missing plane of pilot steve fossett.

narrator: a few days later, investigators reach

the mangled wreckage of fossett's plane

outside of mammoth lakes, california,

just 65 miles south from where he took off.

man: what we have learned thus far

is indicative of a high-impact crash

which appears to be consistent with a non-survivable accident.

narrator: the initial investigation reveals

that at the time of his crash

his plane was in perfect working order.

the dossier details testing of advanced aircraft,

or mechanical failure. it wasn't alien technology

the nevada triangle has claimed another pilot

in mysterious circumstances.

with no clues emerging from steve fossett's wreckage,

the ntsb pursues a new culprit: the weather.

and it turns out, the weather here

is among the most complex and unpredictable in america.

the sierra nevadas are 400 miles of granite

that vary in elevation.

there are hundreds of peaks higher than 12,000 feet,

and at those heights, weather can change very rapidly.

zach tolby: we just issued a severe thunderstorm warning

for central washoe county.

they need to keep their new venture top-secret,

and crashes in the area.

birnes: why are there so many plane crashes in this area,

the nevada triangle?

well, one theory is this: that because ufos,

either the ones we're testing

from here, or the ones that don't come

fly around in this electromagnetic envelope,

instruments fail, compasses go haywire,

and in the worst-case scenario,

the ignitions of jet engines fail.

narrator: the mysterious reputation of area 51

has its roots in the 1950s,

when the cia partners with the lockheed aviation company

to build and test aircraft.

is the reason behind aircraft disappearances

so they choose this remote location in the nevada desert.

named simply by its map coordinates,

area 51 sparks the imagination

of many conspiracy theorists in the united states

and around the world.

peter merlin is a well-known aeronautical historian

who has been studying area 51 for 30 years.

he also thinks that the heavily guarded base

is behind many of the crashed planes littering the area.

watched right now peter merlin: we're being

by area 51 security.

they detected us coming in using road sensors that are magnetic

to detect any metal object coming by, like a truck.

the whole time now he'll be watching us

because a flying saucer or a flying wedge-shaped object

believes that the high number of crashed aircraft in the area

is due to the fact that the triangle's footprint

includes the secret base known as area 51.

bill birnes: so right over those mountains over there,

the famous, the historic, the mysterious area 51.

the legend is that all the way back from the 1950s,

at least through middle 1990s,

you could be shot on sight if you crossed the border.

narrator: the high level of secrecy surrounding the base

attracts plenty of controversy--

controversy that can be traced back

to the so-called roswell incident.

birnes: in july 1947, some people say

that human history changed

as long as we're out here,

crashed outside of roswell.

initially when the army saw the material,

they didn't know what they had.

all they knew was it wasn't from this world.

then they decided

what it is ourselves, if we can't figure it out

of the top engineers, let's get some

the top scientists, the top metallurgists,

in complete secrecy. let's bring them to area 51

narrator: in 1994 the pentagon releases a report

exposing the roswell incident

as no more than a downed weather balloon.

but bill still believes that alien technology

the sightings of the unusual winged aircraft

like air-to-air combat or air-to-ground combat.

all of these are exceedingly hazardous.

to have lots of crashes. it's not at all surprising

narrator: one of those early crashes

is the lockheed u-2 spy plane in 1957.

it is the first airplane ever tested in area 51

and very likely the source of the initial rumors

that link area 51 to captured alien technology.

the u-2 spy plane program

is partially declassified in 1998 by the cia.

although not mentioning area 51,

the file contains details of an incident in the 1950s,

when the prototype flies

at altitudes no one believes possible.

where combat planes are used in mock exercises

prompt many reports of unidentified flying objects

in the area.

what the locals are actually seeing isn't alien,

but a marvel of human ingenuity.

the history of area 51 merlin: i've been researching

for more than 30 years.

any evidence whatsoever i've never seen

to do with extraterrestrials. to suggest there's anything

built right here on earth. it's all advanced technology

narrator: in 2013, after decades of being called

"the most famous military institution that doesn't exist,"

the cia finally releases hundreds of declassified papers

confirming the existence of area 51.

there's an f-4e

to the border of area 51. 'cause we're very close

narrator: but merlin has no time for talk of alien technology.

merlin: i think the idea of aliens being involved

with any plane crashes in this area is just rubbish.

narrator: merlin is drawn to this part of the nevada triangle

for evidence that points to a far less exotic explanation.

merlin: this is definitely wreckage from an f-4 phantom ii.

from the side of the aircraft; we're looking at a part

from one of the engines. it's the air intake

and there's a piece up here that's got a part number

an f-4 part number. that's very definitely

narrator: peter merlin has been hunting downed aircraft here

for decades.

to the crash site of an f-4d. merlin: we're very close

narrator: the sierra nevadas.

in tempait mountain across the valley.

there's an f-16 down in rachel.

uh, british harrier crashed over the mountains there.

uh, in railroad valley

that collided in mid-air. you've got two f-15s

all of this took place during routine testing and training.

and these are just the crashes i can think of

off the top of my head.

there are dozens more just in the local area

and hundreds in the surrounding desert.

narrator: he thinks the reason

for the high number of military crashes is obvious.

merlin: this is a place where high-tech airplanes are tested,