on a stormy Halloween night a passenger
plane begins a routine landing but what
happens is far from routine
investigators must determine what
terrible chain of events brought it down
nose-first killing everyone aboard in
the fog
a Canadian commuter plane aborts a
landing maneuver seconds later it plows
full-speed into the woods nearby was the
accident caused by mechanical failure or
a fatal lapse of judgment the answers
are preserved in the indestructible
black box dutifully recording a planes
final maneuvers and the clues last words
black boxes help investigators make
sense of the fields of destruction
after a crash a black box is often the
only surviving witness to terror
[Music]
on the evening of October 31st 1994
American Eagle flight 4184 took off in
the rain from Indianapolis to Chicago
less than 200 miles away as the
twin-engine turboprop approached its
destination air traffic controllers told
the crew to expect delays a fierce storm
was backing up traffic outside O'Hare
International Airport
the plane was put in a holding pattern
over a rural section of northeast
Indiana
the pilots noticed some icing and
activated equipment to crack it off the
wings
they depended on the autopilot to keep
the plane steady and to maintain
altitude attendants tried to reassure
passengers that they would make their
connections all the other flights were
delayed to one of the busiest airports
in the world was at a total standstill
in an announcement reconstructed from
transcripts the captain tried to
reassure the control the plane had been
holding for more than 30 minutes because
of the storm some passengers have
debated whether to board the flight
now they grew increasingly anxious
finally the transcripts indicated that
controllers cleared like 4184 to begin
landing procedures
they left
it was the last communication flight
4184 would have with controllers as the
plane began its descent something went
terribly wrong
continue to descend picking up speed
7,000 feet 6,000 people five
at 4,000 feet
[Applause]
the aircraft plunged into a muddy
soybean field in rural Indiana
chattering on impact
fighting driving rain and freezing
temperatures rescue workers searched
through the night for any sign of life
from the 72 passengers and crew
finally they faced the truth no one
survived when an airplane crashes in the
United States it's up to the National
Transportation Safety Board the NTSB to
determine what went wrong Greg Feith was
the lead investigator in the case of
flight 4184 when I go out to an axe
inside I'm playing Dick Tracy my job is
to go out and find all the evidence all
the clues to tell us what happened the
public demands answers and looks to the
NTSB to provide them fast so agents are
brought in quickly they are often among
the first to witness the devastation it
can be very overwhelming I mean it's an
emotional thing because when you're
walking through all of this wreckage
you're seeing pictures you're seeing
teddy bears you're seeing clothing of
children and things like that
so you can't help but start to become
emotionally attached but as an
investigator in order for me to remain
objective you have to separate your
emotion out of that and you got to block
it out so that you can do your job and
do it effectively and that's not always
easy for us as the Sun rose the next
morning it revealed the true horror of
the accident impact craters marred the
once peaceful farm transforming it to a
field of death
the narrow country roads of Roselawn
Indiana bustle dwith truckloads of
rescue equipment and the clamor of news
crews a team of forensic aviation
experts from the NTSB arrived their job
was to create order from the growing
chaos so they could focus on the
difficult task of figuring out what
happened immediately what our
investigator and the team will do is
actually what we call document the four
corners we want to look for all of the
wreckage we want to make sure that both
wings are there the tail section is
there the engines are there but the
investigation was hampered by health
risks fuel covered everything the site
was declared a biohazard only those in
safety gear went in and out rescue
workers and investigators teamed up to
flag evidence and remains they worked
side-by-side examining every piece as
soon as possible
parts of bodies were transported to the
morgue to begin the difficult
identification process for us the
investigators we're looking at physical
revenant evidence of the airplane that
is the wreckage itself for the coroner
who has to go out there and look for the
bodies or the victims they had as tough
of time as we did because they didn't
have whole people they had fragments of
people and so for both of us to do our
job we had to work hand in hand because
if I found a piece of wreckage there may
have been critical evidence for the
coroner in in a piece of victim and so
we worked hand in hand when we're
looking at all of this wreckage so that
I could help him collect whatever
evidence he needed to identify the
people that were on that airplane as
bodies were identified they were
released for burial family members found
solace in each other and in the
chaplains and counselors who volunteered
to help but in the midst of family
sorrow investigators kept working they
scoured the soybean field for answers
to figure out how the plane broke up
they viewed the wreckage from above they
examined the scars in the earth created
by the impact and the locations of the
scattered pieces of airplane the
patterns can tell them if a piece broke
off on impact or if it fell off during
flight causing the accident what they
found in the ruins of flight 4184 was
startling typically when you have an
airplane that's either come straight
down or made an emergency type landing
you'll find the initial impact point and
then wreckage you no detail or
fan-shaped pattern with this particular
accident site we had a very high speed
high angle of attack impact into the
ground so we had a main impact crater
but we found the tail section in a very
oddball place in relation to the main
impact crater that led to the team of
the thing how did that get there and it
was an evident that it was an in-flight
breakup so the tail had come off before
the airplane hit the ground now
investigators had a possible explanation
a structural failure may have caused the
tail to break off in flight but airplane
tails don't just break off something
must have triggered the failure more
evidence needed to be examined more data
gathered the weather that night provided
the first clue the conditions were ideal
for icing too many the freezing rain in
which the plane was flying could have
been a major factor but it seemed
unlikely that icing on the wings could
cause the tail to fracture the only way
to determine what really happened would
be to look inside the planes black box a
black box is actually two boxes and
they're not black they're orange making
them easier to find
one contains a record of the plane's
mechanical workings it's called the
flight data recorder the other is the
cockpit voice recorder basically a crash
proof tape recorder it contains an
account of everything the pilots saved
it also picks up alarms engine noise and
perhaps the horrifying sound of impact
within hours the boxes were whisked away
to NTSB headquarters in Washington DC
their technicians prepared them for
analysis sometimes black boxes provide
instant answers other times they only
deepen the mystery as investigators
prepared the playback equipment they
also prepared themselves they'd be the
first to hear what the pilot said as
they face death head-on
[Music]
after maintaining a holding pattern near
O'Hare Airport flight 4184 was cleared
to descend from 10,000 feet seconds
later the plane crashed into the earth
killing everyone aboard
now investigators would listen to the
cockpit voice recorder as the plane
began its fatal plunge the crews words
during the terrifying last moments are
taken from transcripts
[Applause]
just below okay
the chilling tape made it clear the
pilots were completely broadsided they
didn't know they were in trouble until
it was too late but it raised more
questions than it answered
investigators were no closer to learning
what happened their last hope lay inside
the second box the flight data recorder
or FDR now all the plane's mechanical
functions or malfunctions would be
analyzed
Doug brazii is a blackbox expert at NTSB
he's responsible for turning the
complicated bits of data from FDR's
into useful information the data
recorded by an FDR depends on the age
and type of plane it's in the won on
flight 4184 monitored about 100
mechanical functions
Bracey downloaded the information to a
computer using tape decks that translate
the coded data the information appears
as charts and graphs on the computer
they represent the pilots actions and
the airplanes performance in the final
minutes before it plunged to earth the
readouts were placed side-by-side on a
time line to see their relationships as
the data appeared breezy discovered the
plane had experienced an abrupt
catastrophic event
[Music]
to get a better understanding he created
an animated version of the plane's last
moments it's very difficult to get a
sense of time and how quickly or slowly
things can unfold from looking at
numbers and graphs the animation helps
us see how quickly or how slowly things
develop in the accident sequence the
animation combines all the planes
functions just before it fell into a
visual model that investigators can
study it began as the plane started its
descent from 10,000 feet without warning
the autopilot disengaged the ailerons
flaps on the wings that control flight
suddenly flipped the plane rolled
violently to the right the pilots grab
the controls and struggle to level out
but the speed of the roll was too great
it yanked the controls out of their
hands and the nosedive toward earth as
they burst through the clouds the ground
filled their windshield rushing toward
them at 400 miles per hour futile II the
pilots pulled back on the controls to
bring up the nose the resulting strain
on the tail was too great it snapped off
just before the plane hit the ground the
animation made the sequence of events
tragically clear
the airplane was in flight when the
airplane rolled initially rolled to
approximately 77 degrees the first time
and the nose started to pitch down the
first officer was able to recover it
slightly and as he tried to pull the
nose back up the airplane then rolled
again completely through 360 degrees the
nose pitched down and the roll continued
another approximately 140 degrees until
the first officer was able to get the
the roll stopped but because of the very
steep attitude that the airplane was in
and as he tried to pull out he had a lot
of aerodynamic force on the tail section
of the airplane because he was pulling
extreme he was actually moving these
flight control surfaces to their maximum
high aerodynamic loads this part of the
airplane literally came off and the
airplane then basically went over on his
nose striking the ground and then
fragmenting and is it fragmented this
part of the aircraft ended up getting
slingshotted to the furthest point in
the wreckage area it was now evident
that the crash wasn't caused by the tail
breaking off in flight that left icing
as the probable cause but braising new
icing would normally show up on the
screen as a slow steady buildup not a
sudden Cataclysm what could have
overpowered the plane so quickly and
sent it careening to earth
knowing what makes a plane fly can
provide clues to how it can fall at
embry-riddle university in Prescott
Arizona wind tunnels are used to
demonstrate the aerodynamics of flight
here the invisible forces of wind are
made to glow unveiling the basic
principle of flight
the faster that air moves over a surface
the less pressure it exerts the slower
moving air underneath pushes upward
causing the surface to lift
aerospace engineer Richard Felton who
demonstrates the principle with a simple
experiment
let me demonstrate with a sheet of paper
if I might I'm going to blow over the
top of the surface of paper so I'm not
going create anything below there's no
magic here at all okay and as you can
see the paper actually raises wings are
not flat like paper but they work the
same way the air moves faster across the
round top of the wing because it has
more surface to cover but it's critical
that the top surface be smooth and that
nothing on it disrupts the flow of air
if the air flow is disturbed the object
loses the pressure that lifts it any
foreign objects on the wings can disrupt
the airflow
for instance ice can build up then break
off leaving jagged edges that may
produce enough turbulence to bring down
a plane flecked 4184 was an ATR 72
series airplane Roselawn investigators
discovered that these planes had a
history of icing problems but the FDR
showed that its de-icing system was
working properly and the readout didn't
show normal icing patterns then
investigators learned of a weather
phenomenon called supercooled drizzle
drops extra-large freezing rain a check
with meteorologists told them the
conditions that stormy Halloween night
were right for this phenomenon to occur
was whether the fatal factor
[Music]
to find out the manufacturer of the ATR
took to the skies over the Mojave Desert
in California there they tried to
recreate the exact conditions of the
storm in an experiment called a tanker
test a modified US Air Force jet
produced an icing cloud eight feet wide
an ATR like the one at Roselawn flew
into the cloud the freezing rain clouds
were infused with yellow dye so
investigators could see the ice forming
on the nose and wings to make sure the
tragedy was not repeated test pilots
flew very high for added recovery time
who were prepared to eject if necessary
at first normal freezing rain was
released the small water droplets froze
the instant they hit the front of the
wings but the de-icing boots cracked the
I saw then a cloud of supercooled rizal
drops was released
when the drops hit the wings they didn't
freeze instantly instead they spread
across the wing freezing behind and out
of reach of the de-icing boots at last
the final piece of the puzzle was put in
place typically when the wing has no
contamination on it
these bands or relative wind are smooth
flowing over the top and the bottom of
the airfoil but with the Roselawn
accident when we have the ridge of ice
which is represented by this triangle we
have now disrupted that airflow as the
airflow then reattached or came back
across the very top of the wing it got
very turbulent as it came off the
trailing edge which is represented by
this area right here that turbulence was
right over the top of the ailerons and
when the turbulence created a very low
pressure system this ailerons started to
move from a like a neutral position up
to its maximum deflection of 14 degrees
in a quarter of a second now
investigators concluded what happened
that night and why the pilots were in
the holding pattern they were chatting
the autopilot was on they thought
everything was fine what they didn't
know was that behind the de-icing
equipment a ridge of ice was building up
as they started to descend the ice
cracked off what remained left ragged
edges on the wing causing turbulent
airflow the turbulence created a
powerful low-pressure system that acted
like a vacuum it literally sucked the
ailerons up forcing the plane into a
roll attempts to write the plane only
snap the tail
the plane then dove into the earth
[Music]
afterward all was silent except for the
driving rain and then silence
the crater in a soybean field in
Roselawn Indiana is a scar that can
never be healed
but by solving the accident
investigators have done all they could
after the investigation the ATRs
de-icing system was redesigned extending
farther back on the wing and ATR pilots
are now trained for icing conditions
the work of the NTSB and others on the
Roselawn case helped to reduce the
chances of a similar accident happening
again every airplane crash is the result
of a fatal mixture of conditions the
ingredients come from the plane the
weather and the pilot himself in Canada
investigators tried to reconstruct a
commuter planes recipe for disaster the
mountains of British Columbia are among
the most breathtaking in North America
but for pilots flying through them they
can be treacherous
in 1989 two young pilots at Sky link
Airlines were flying five commuters in a
19 seat turboprop from Vancouver to
Terrace just over 400 miles away they'd
made the trip dozens of times and they
were familiar with the dense morning fog
that often drifts through this part of
Western Canada
the morning of September 26th was the
start of just another day
shortly before flight 70 made its final
approach to the runway a 300-foot fog
bank engulfed the airport bringing
visibility to zero the pilot expected to
see the runway lights pierce the fog at
any moment instead he saw only even as
the plane swooped down for the landing
he had second thoughts and safely
aborted the manoeuvre but as he pulled
away treetops suddenly loomed large
through the tent
[Applause]
the airplane plowed through the branches
rolled and burst into flames the pilots
and passengers were killed on impact
investigators from the Transportation
Safety Board of Canada were assigned the
horrible task of making sense of the
tangled wreckage trees had cracked and
fallen onto the fuselage one of the
wings had sheared off the cabin was
crushed the cockpit was peeled open
exposing a snarled mass of wires cables
and circuitry the force had twisted and
snapped off the propellers it took days
to find pieces of aircraft that hurtled
into the forest reading the wreckage
would take even longer now it's a
forensic skill that requires intensive
training at embry-riddle university
would be investigators gain experience
by studying the remains of actual
crashes reconstructed on the site
director of aerospace safety bill wall
doc instructs his students in what to
look for and how to find it
well just like in a crime scene what I
want the students to be able to do is to
identify all of the things about this
scene that are significant to be able to
find all of the parts to be able to
understand how those parts got where
they were and what they mean and then to
be able to take that and put it into the
rest of the story and literally fit all
the pieces of the puzzle back together
and come up with a clearer picture of
what happened to this aircraft and why
it happened
according to wall dock finding out what
caused a crash is the first step to
preventing another one
the main purpose we do investigations is
to try to figure out what happened and
why it happened and once we've done that
then we can go change things and try to
improve the rest of the system it's an
expensive way to learn but usually it's
one of the most impressive ways to learn
then we get the point across pretty well
that way every detail of the wrecks is
painstakingly duplicated right down to
the flames if a crash site is on fire
it's crucial to determine if the flames
started in the air or on the ground a
plane that burns then crashes shows a
different pattern than a plane that
crashes then burns a fire that ignites
during flight generally burns hotter
than a fire caused by impact because
it's fanned by the rushing wind
according to wall doc pre impact fires
leave a distinctive signature one of the
things that we look for in considering
pre impact fire versus post-impact fire
is evidence that metal was hot when it
hit the ground right in this area of the
engine compartment on the left side you
see a little bit of feathered aluminum
to get that aluminum to broom straw or
feather that metal has to be up near its
melting point and right here we see a
little bit of evidence that that process
has occurred that tells us that we had a
pre Empire in this left engine
compartment
less than 7% of fires occur on impact
but when they do they make the
investigators work much more difficult
when rescue crews put out the flames the
force of spraying water moves parts a
considerable distance and the fire
itself can destroy valuable evidence
fire will tend to get rid of our
physical evidence we're looking for for
example fatigue in a metal structure if
the airplane caught on fire when it hit
the ground it'll tend to erase that
evidence and to burn it away and fire is
one of the worst things we can do at the
crash site in Canada fire was only the
first of the many challenges
investigators would face burn patterns
showed that the fire was the result of
the impact not the cause of it lead
investigator Roger Ayotte recalls the
scene the aircraft had crashed to some
1500 feet away from the airport and the
actual crash site itself was not
particularly large the airplane that hit
the ground at at fairly high speed and
the destruction was was considerable and
certainly wasn't evident when we went
onto the accident site but what the
problem had been when we did start
examining the wreckage we realized that
the aircraft in fact had impacted the
ground inverted because the engine
positions were were switched on the
ground hayaat and his team reasoned the
fog may have played a role but only a
minor one
the pilots were too experienced the
collision - fast and furious the
devastation - complete in the charred
rubble investigators located the flights
black boxes still bolted to the tail
their bright orange exteriors were
camouflaged with soot
perhaps the boxes would reveal what
happened they were flown to
Transportation Safety Board headquarters
in Ottawa for analysis
in the lab black box expert Michael
Poole and computer analyst Bob Hoyle
were stunned by what they found
the flight data recorder should have
been an electronic device that captured
most of the planes mechanical functions
on magnetic tape or microchip instead it
was an unauthorized and antiquated model
invented in 1951 its use had been
prohibited in many countries rather than
electronic circuitry the Box used a
stylus to etch information onto a moving
roll of foil okay the flight data
recorder on this aircraft was an old
design it was a foil type recorder which
is a metal foil which and five
parameters are inscribed on the foil and
of those five heading which is a key
parameter was actually not functioning
so we in fact only had four parameters
and in contrast with today's modern
aircraft which have five 600 parameters
per second obviously there's a very big
difference here so we had a very limited
flight data recorder the data on that
recorders also the resolution is very
poor and it's extremely time consuming
to extract the information off of these
foil type recorders in its time the foil
recorder was a technological advance
because it could survive impact and fire
now it's primitive workings threatened
to [ __ ] the investigation
to eke out some meaning from the foil
scratchings foil scanned them into a
computer perhaps modern technology would
give its predecessor a helping hand
Coyle was able to sharpen and focus the
information from the coarse edgings
enough to interpret them the FDR showed
that the plane flew an unwavering course
into the trees at more than 200 miles
per hour but one mark indicated
something strange a sudden burst of
speed just before the plane struck the
information was incomplete and
contradictory why would a plane in the
midst of an aborted landing suddenly
plunge into the ground pool and his
colleagues turned to the cockpit voice
recorder for an explanation they found
only more contradictions the pilot told
the copilot they were going to abort the
landing go around and try again on the
tape in the background the engines
roared to full power that was consistent
with a climb but it wasn't consistent
with the disturbing final exchange
between the pilot and co-pilot
transcripts indicate the copilot began
to warn that the plane was losing
altitude
when we first listen to the voice
recorder it was quite quite perplexing
because the crew had initiated a missed
approach they were starting to do a
go-around we could hear engine power
coming up they were asking for gear up
they were asking for flaps up they were
starting to climb out and for some
reason the airplane transition from a
climb out to a descent and crashed very
quickly so this was quite puzzling and
that was really where we started to
focus why was this airplane which should
have been able to fly out shouldn't have
been a big problem transitioning from an
ascent to a descent and hitting the
ground the black boxes yielded only
vague clues they held none of the hard
data pool had come to expect from them
he relayed the bad news to fellow
investigators the gaps left by the
primitive data recorder would have to be
filled in manually a team of nearly a
dozen forensic aviation specialists
would have to engage in hardcore
old-fashioned detective work fortunately
they had an arsenal of sophisticated
tools to help them the first step was to
determine if the damaged engine was the
cause of the crash or the result of it
for that investigators depended on
engineering services specialist John
Garstang as part of the crash site
investigation we saw that the right
engine was extensively damaged and
disintegrated in order to understand
this damage whether it occurred in
flight or incurred in the ground as a
result of ground impact we had to know
how the aircraft broke up that's where
we use tree information together with
the attitude that had hit the ground to
determine the break-up sequence Garstang
specializes in coaxing clues from places
investigators can't go like the tops of
the trees he mounted a stereoscopic
camera on a helicopter and shot 3d
photos of the damaged trees
he used these photos to determine the
angle at which the plane struck the
forest this is the crash site the red
dots are pieces of wreckage the aircraft
initially descended through the forest
starting here all the black dots are
trees that have been damaged most of
which had been cut by the aircraft he
then created a model showing the path of
the plane as it plowed through the trees
it showed the plane was level as it
clipped the treetops both engines must
have been in place keeping the plane
balanced the roll didn't occur until
after it hit the trees Garstang
concluded the engines were attached on
impact now he had to see if they were
working properly
erratic moves in the final flight path
of the plane might hint at an engine
problem but because the FDR didn't have
the data Garstang needed he had to
devise a clever way to reconstruct the
plane's movements he made a map showing
the locations of witnesses when they
heard the plane we used the location of
witnesses on the ground and through
triangulating from where they are to
where they either saw the aircraft or
heard it we were able to determine that
the general flight path was in a arc
like this that came approached towards
the airport in this direction and then
ultimately the plane crashed over here
witnesses determined the flight showed
no sign of trouble and they provided
Garstang with other useful information
initially we heard that the witnesses
heard noises or sounds like a WoW engine
pitch that made us wonder whether there
is possibly an engine problem or a
propeller problem and at the crash site
we were missing pieces and there's an
extensive damage done to the right
engine that initially led us to try and
focus in that area to see if that was an
area of concern engine trouble is often
the cause
small plane crashes to see if it was
behind this accident chief analyst Bill
Taylor dissected the battered engines
when we're doing an engine investigation
and doing a teardown there are two or
three things that we're looking for
first of all we want to see whether
there's been a mechanical failure in the
engine that's most apparent most obvious
and the easiest thing to do the second
is to look for evidence of the power
level and that's very helpful in an in
an accident investigation to just
discover whether the engine was
producing full power and maybe running
but running at low level that idle as
you might say it's it gives an
indication again of what was available
to the crew at that time if the engine
was at full power when it crashed it
would bear the scars of its moving parts
as they struck the engine body deep
markings indicated the engines were at
high power the large amount of dirt and
debris sucked into it on impact
confirmed that finding Taylor gave the
engines a clean bill of health he
determined the wowing sounds heard by
witnesses were normal engine sounds
bouncing off the uneven terrain he'd
have to look elsewhere for answers
he checked the landing gear it too was
working it was nearly retracted at the
time of the crash consistent with the
procedure for an aborted landing so far
the plane seemed in perfect working
order
no clues had surfaced investigators were
stymied but was it possible something
was driving the pilot to land quickly
and take risks could he have been
running out of fuel John Garstang used
infrared photography
to find out what we have here on the
left is a conventional color photograph
of the forest and on the right is what's
referred to as a near infrared
photograph in conventional photography
fuel blends into the natural shadow but
shot with near infrared film the spray
of fuel appears as a dark stain records
like the weight balance gave us a good
indication of what the fuel quantities
should be and we use the infrared
imagery to confirm that there was
sufficient quantity or a large quantity
fuel print at present we have the ground
scar here left by the right wing and you
can see a general area of discoloration
where the fuel has been sprayed as well
as there's been a ground fire and
branches have been broken the
photographs revealed the plane arrived
at the airport with fuel to spare
another dead end for the investigators
according to all indications flight 70
should never have crashed but it did and
until investigators figured out why the
tragedy could recur the nagging question
remained after aborting the landing why
would the pilot start to climb and then
dive into the earth engineer Jim foots
checked the accuracy of the aircraft's
instruments perhaps they were lying well
we look at the instruments and which
leads to looking at the dial phases and
in the internal mechanisms of the
instruments because again not all FDR's
record all parameters so we can look at
add the instruments and at times get
information from the dial face such as
pointer slaps gear train damage and they
will tell us what that actual system was
doing at impact if the impact was severe
enough the pointer would slap against
the dial face and leave a mark even if
the pointer was lost the tell-tale mark
would remain most of the instruments
were destroyed beyond recognition
only the altimeter survived and it
showed the plane's altitude setting was
right where it should have been the
pilot should have known how close to the
ground he was once again the solution
remained elusive but foot's had his
suspicions if the plane was going down a
warning system should have alerted the
pilot unless the warning system itself
was faulty he directed his attention to
the warning lights light bulb filaments
can tell a great deal about conditions
at the moment a plane crashes well we do
light bulb analysis even if the aircraft
does have an FDR or CVR if the FDR gives
us an indication that there was a
problem a warning then we can look at
the light bulbs and and actually say
yeah this light was on and that the
pilot did have a warning or a caution
light a bulb that's lit when it's broken
reacts very differently than a bulb
that's off it's easy for the trained eye
to spot the difference what we're
looking at here is the filaments
and what we look for with the filaments
is deformation as you see here total
uncoiling of the filament which is
indicative of a hot or illuminated
filament when impacted as opposed to a a
lamp that was off or cold at impact
where we have just a straight brittle
fracture foot's found that none of the
37 surviving warning bulbs from flight
79 but that didn't necessarily mean all
was well with the craft still searching
for clues investigators focused again on
the position of the aircraft while
attempting to abort the landing
perhaps the planes nose tilted too high
at a steep angle air can't glide easily
over the wings the plane stalls and
drops from the sky
in order to figure out a flight 70
stalled investigators would have to
climb into the pilot seat
whatever happened to Sky link flight 70
came without warning now investigators
had to reconstruct the tragedy the stall
avoidance system on this type of
aircraft was notoriously unforgiving it
provided very little notice to the pilot
before a stall at low altitude the
difference between stall and crash and
life and death is mere seconds to see if
the planes pitch or angle in the air
would cause a stall investigators needed
to reconstruct its final moments for
that they needed a flight simulator they
fed in all the data they collected along
with pilot commands from the voice
recorder the simulator would combine
these disconnected clues into a close
estimate of the plane's position we knew
what the altitude and airspeed of the
aircraft was at the start of the mist
approach we also knew when they added
the power when they retracted the
landing gear and when they retracted the
flaps so we were able to come into the
simulator and use those parameters that
were available off the flight data
recorder and fly the airplane in
accordance with those parameters and
then through that process determine what
the pitch attitude of the aircraft was
if the pitch was too steep the plane
would have stalled then crashed but that
wasn't what happened
the simulator showed the plane's pitch
was fine stalling and a faulty stall
avoidance system were ruled out after a
tireless examination of the plane from
nose to tail investigators could finally
rule out mechanical failure
they had only one more place to find
answers
with the man in the cockpit to determine
if human error was at fault
Roger Ayotte needed to get inside the
pilots head once we had eliminated the
possibility of any of mechanical
malfunction of the aircraft and that was
probably a couple of months I into the
investigation then we were able to focus
all of our efforts on the operational
and human performance sides of the
accident while one type of investigators
searches for physical clues another
looks for psychological ones blackbox
expert Mike Poole created a voiceprint
turning emotion into a picture and human
performance investigators Ron Coleman
and Beth McCullough
were brought in to study it to explore
what was going on in the minds of the
pilots they scrutinized their final
words when the copilot alerted the pilot
they were descending the pilot answered
calmly with a simple okay McCullough
felt there was far more going on than
the first playback led them to believe
but if you've got someone next to you
who's obviously expressing concern and
and and in a rather agitated voice then
you begin to wonder and that might be
your first question is this captain
being really calm about the situation
has it fully under control or is he
unaware of the gravity of the situation
[Applause]
first thing that we picked up was the
anxiety in the copilot's voice when he
uttered the second descending after that
we went back listened to the entire tape
many many times to try and determine the
various operational issues that might
have emerged or did emerge and also some
of the human performance issues that
were clear just from listening to the
voices and the pauses and his
from the voice recording Coleman and
McCullough surmised that the pilot
sounded unconcerned oblivious to the
fact that he was speeding towards
certain death they ruled out suicide
psychological profiles were normal the
investigation team suspected the pilot
was literally lost in the clouds he
didn't know which way was up and he
wasn't trusting his instruments or his
co-pilot to set him straight
did pilot error caused the crash the
team was close to figuring it out
but before they could more testing was
necessary was the pilot of flight 70
truly disoriented in the fog to
illustrate what he might have
experienced Mike Poole collated the data
and produced an animated version of the
fatal flight next to it he created an
illusion plane it was based on what the
human performance experts believed the
pilot may have perceived call a missed
approach he asked for the gear to come
up the gears selected up he calls for
the flaps to come up and the first
officer has responded with flaps coming
up to half
shrouded by fog unable to see the runway
the pilot searches for visual clues
outside his window in his efforts to get
his bearings he fails to notice his
gauges or to heed his co-pilots concern
what we know and from our operational
investigators suspect that he is maybe
adjusting the throttles in the cockpit
he's maybe unfamiliar with his flight
director he's in fog he's perhaps a
little bit lost in respect to where
exactly is the runway is it to my
writers to my left so all these factors
can be distracting him from that task of
watching those instruments the animation
showed that the pilot did indeed confuse
up with down the condition is called
somewhat a graphic illusion it occurs
when pilots are deprived of visual cues
instead they rely on gut instinct
basically the human body cannot
distinguish the difference between a
force through your stomach pushing
against the back of your chair due to
thrust due to being accelerated down a
runway for example or the same force due
to pitching you up and feeling the
effects of gravity pushing you back in
the chair though the pilot may have been
operating under an illusion the
consequences of his actions were
dreadfully real investigators went back
to the simulator to experience for
themselves
flight 70s fatal illusion a simulator is
an excellent place to perform a test for
illusions because it's a machine that's
been built to trick the eye and mind in
a simulator you're in a building and
obviously it can't accelerate you down a
runway so but it wants to make you feel
that so to achieve that what they do is
they tilt you back in your chair and you
feel the force of gravity in your chair
and then they fool your visual senses by
taking the horizon instead of you would
normally see it rise they actually keep
it level
so your eyes think the horizons level
you're feeling this force through your
stomach into the back of the chair that
is the sensation of accelerating down
the runway
that essentially is the somatic graphic
illusion Roger
Ayotte took the mock fatal flight all
the data were entered and the horizon
taken away so he could feel the
sensation as the pilot had but he'd fly
under instrument flight rules or IFR
relying totally on his gauges so he
would know where the plane was relative
to the ground okay this is the same
approach being conducted in IFR
conditions so you have to concentrate
totally on your instruments and as you
can see that you have no visual
references outside the cockpit with his
view blocked he couldn't tell if he was
going up or down while accelerating but
the gauges told him he was heading
toward the ground the simulated flight
proved that the pilot had fallen victim
to the illusion you can fly by the seat
of your pants to a certain extent when
you're in visual flight conditions and
that is done frequently however when
you're in instrument flight conditions
so when you're flying in fog or cloud or
something like that then you don't have
those visual senses that you that you do
when you're flying visually the forces
of motion in three dimensions can play
tricks on the mind the inner ear
regulates balance and lets us know where
we stand but it needs a visual reference
it's extremely difficult to overpower
the human instinct to rely on vision
when flying but through sheer willpower
a pilot can stay true to the instruments
until his mind overcomes his body
unfortunately the pilot of flight 70
wasn't aware of the danger
it takes a network of complex systems to
keep a plane in the air it also takes a
tangle of circumstances to send one
crashing down in both Roselawn indiana
and terrace british columbia a
combination of factors conspired against
the aircraft dooming the passengers and
crew but aboard the planes were the
black boxes these indestructible
witnesses coupled with human ingenuity
determined what went wrong by surviving
a crash black boxes enable us to prevent
countless others
[Music]
[Applause]
[Music]