- 2 weeks ago
Air Crash Investigation Series S22E02 Peril Over Portugal
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00:00Martin Air Flight 495 is minutes from landing at Faro, Portugal.
00:06The left engine was making a rattling sound.
00:10All of a sudden, we heard an enormous bang.
00:17It was total destruction.
00:2256 people are dead.
00:26Wow, look at this.
00:28Investigators quickly find some intriguing evidence at the crash site.
00:32There was a two-inch deep cut down the left side of the runway.
00:38This is very strange.
00:40The landing gear is completely severed.
00:44If the aircraft were overweight, it could exceed the design limit, causing it to break and shear.
00:51These guys were 71,000 pounds underweight.
00:55It wasn't too heavy.
00:57So what went wrong?
00:59Martin Air flight 495 is nearing Portugal's southern coast
01:29approach Martin Air 49er 5 good morning the captain is 56 year old HW van Staveren 75 DME and out of 240 for level 70 a highly experienced pilot and flight instructor he's been with Martin Air for 24 years ascending to level 70 the first officer is 31 year old RJ Clemencouf
01:56he's been flying with the Dutch company for three years the youngest member of the team is 29 year old flight engineer Gary glans
02:07it was our last flight before the Christmas holidays everyone was in a good mood my job as a flight engineer I'm responsible for the aircraft in general to make sure that everything is operating properly and overall trying to be a third set of eyes for the flight
02:24third set of eyes for the flying pilots the crew is flying a DC 10 a three-engine wide-body jet in the 90s the DC 10 was one of the type of aircraft most used for operators worldwide they're now less than half an hour from landing there are 13 crew members and 327 passengers on board
02:51most are residents of the Netherlands we were heading for vacation for a week in the south of Portugal in the Algarve going to warmer weather than the Netherlands was and the fleeing the busy year we had
03:07flight 495 is near the end of a two-and-a-half-hour trip from Amsterdam to Portugal's Faro Airport
03:14flight 495 is near the end of a two-and-a-half-hour trip from Amsterdam to Portugal's Faro Airport
03:19I was traveling with Yvonne then my girlfriend now my wife I was lucky we could sit at the front row so I had a lot of leg space to move around
03:38move around oh raining cats and dogs over there as they descend towards Faro Airport the pilots expect to encounter some bad weather we knew that we were going to encounter rain showers thunderstorms are something that you have to be incredibly aware of and ensure that they don't affect your flight path
04:05we do everything to avoid them because they can produce unexpected wind changes microburst wind shears
04:12when a thunderstorm moves over an active runway the potential for wind shear can make it too dangerous for an aircraft to land
04:20it wasn't something that we felt was going to be a major issue it was just something to monitor
04:26if the weather worsens they can divert north to Lisbon but right now it isn't necessary
04:33just minutes ahead another Martin Air flight is landing at Faro
04:41clear to land runway one one one
04:56the weather report indicates the closest thunderstorm is approximately seven miles to the west of the runway
05:03knowing other airplanes were flying that same approach and nobody had reported any significant issues
05:10made us feel we were safe to continue onwards
05:13four nine five is turning inbound
05:15eight miles out Martin Air four nine five starts its final approach to runway one one
05:22the captain chose to be the pilot monitoring so he could oversee the whole approach and let the first officer focus on just flying the aircraft
05:37they descend into the rain clouds confident the nearest thunderstorm is still miles away
05:47four nine five report at minimums or runway in sight runway surface conditions are flooded
06:08roger four nine five with wet runway conditions the crew configures the plane to make what's called a positive landing
06:16a positive touchdown is when the main wheels penetrate the water layer on the runway and improve the stopping ability of the aircraft
06:25you're down you're down with a wet runway you do want to touch down at a positive firm rate rather than trying to float down for a softer touchdown
06:40altimeters
06:42altimeters
06:43set three times
06:45four miles from touchdown the pilots make their final checks
06:49spoilers
06:51arm
06:54flaps slats
06:565-0
06:59land
07:01the left engine was making quite a noise and a rattling sound every time it gave full power
07:14the plane was pitching up and pitching down
07:20so that was not reassuring
07:22martin air four nine five clear to land runway one one the wind one five zero one five knots maximum two zero
07:38clear to land
07:40flight four nine five is less than a minute from touching down
07:45when the weather gets much worse
07:49we shield anti ice I can't see anything
07:52I'm on it
07:53wipers are on fast
08:04it's okay
08:05it's okay
08:06it's okay
08:07I was squeezing hands firmer and firmer with the phone
08:14it was dead quiet in the plane
08:24the plane is now just a few seconds from landing
08:31all of a sudden we heard an enormous bang
08:37I fell out of the chair
08:40I fell out of the chair
08:42and then I saw the kitchen splinter into pieces
08:51I was pretty sure we were going to be crushed
08:57Flight four nine five slides more than three hundred and fifty feet off the runway at Faro Airport
09:02firefighter and rescue crews race to the site
09:05firefighter and rescue crews race to the site
09:11incredibly many of the passengers and the flight crew survived
09:17there were people screaming and crying and running
09:20I didn't see my girlfriend
09:27my first thought was oh I won't ever see Yvonne again
09:33those lucky enough to escape search for loved ones
09:38all of a sudden I heard my name
09:41then I saw in the distance I saw Yvonne standing there
09:48we found each other
09:51the injured are taken to nearby hospitals
09:56of the three hundred and forty people on board
09:59fifty-four passengers and two cabin crew members are dead
10:02making this one of Portugal's worst aviation disasters in more than a decade
10:20a detailed investigation is now underway into why this plane hit the tarmac and burst into flames
10:25see if we can find the flavor corners
10:39got it
10:41investigators from Portugal's general directorate of civil aviation
10:45and from the American NTSB arrived to inspect the wreckage of Martin Air flight four nine five
10:51a DC 10 is a big aircraft and there were pieces of it all around
10:57the right wing it dislodged from the rest of the aircraft
11:01the wing structure is the strongest structure on whole aircraft
11:07so it had to have a major amount of stress to make that wing depart
11:12it's amazing so many survived
11:14the record showed that the aircraft was mostly destroyed by fire
11:20eighty to ninety percent of the people died died from the post impact fire
11:26we are very concerned because if you have something that's suspect on an aircraft that's being flown all over the world
11:34you want to find it
11:36that's great nice work
11:37let's hope we get the data back quickly
11:44investigators recover the black boxes containing the flight data recorder and cockpit voice recorder
11:51we needed to try to understand what happened in the final moments of the flight
11:56in terms of speeds in terms of decisions and also what happened just before a touchdown
11:59wow look at this a quarter of a mile from the runway threshold investigators discover the aircraft's initial point of impact
12:16there was a two inch deep cut down the left side of the runway
12:21so it hit here and then veered off to the right
12:25it's deep
12:27it must have come down hard
12:32the scratches we saw on the runway revealed to us that the plane landed very hard
12:37so that's why the marks were deep
12:39maybe one of the engines failed
12:41why did the plane land so hard?
12:44was it a problem with the landing gear?
12:47was it a problem with speeds?
12:48or was it a problem with the engines?
12:51so we need to investigate that
12:55is that all of them?
12:57let's see what we've got
12:59you always look at the engines
13:02and there was substantial damage
13:06we had to determine was there some kind of malfunction
13:10in the engine
13:13investigators examine a key component from the engine's oil block
13:16called a magnetic chip detector
13:18a magnetic chip detector
13:20a magnetic chip detector is a small cylinder shaped device located inside the engine's oil filter
13:27when an engine part wears pieces or chips of broken metal adhere to a magnet as they pass through the oil filter
13:36it's known as making metal
13:39why is there more metal on this detector than expected?
13:43what part of the engine is wearing?
13:46the alloys are slightly different
13:48they wear at different rates
13:50so they can tell by laboratory analysis
13:53what part of the engine is wearing and how rapidly
13:56and how rapidly?
13:57these look clean
13:58these look clean
13:59no chips
14:02there's no evidence of metallic debris inside the oil system
14:09the engines look fine
14:11from the tests conducted on the engines
14:13it was concluded that the engines did not contribute to the accident
14:19at this point in the investigation we really didn't have a good idea of what to look for next
14:25we just had to keep going
14:26this is very strange
14:38they soon realize that part of the right landing gear is broken
14:43the fact that part of the right landing gear fractured is very unusual
14:49it's almost impossible to make it fail
14:52the forces necessary to shear the landing gear like that is massive
14:57landing gear is designed and tested to be able to withstand the shock of a 200 ton landing
15:05it should never fracture
15:07we had to confirm whether there was something wrong with that gear in the metal used or maybe the maintenance on it
15:17anything that could cause the gear to fail in any way
15:21and if it was a design problem that's a big deal
15:25the landing gear failing on impact would explain this tragic accident
15:30did we get this piece of landing gear in yet?
15:37not yet
15:39we're rushing
15:44the landing gear collapsed
15:46that was perhaps the most important question that we had to deal with
15:51while investigators wait for the right landing gear of flight 495
16:02they consider what could have caused it to fracture
16:05maybe the plane was too heavy
16:08if the aircraft were overweight and made a very firm touchdown
16:12then the loads imparted could exceed the design limit causing it to break and shear
16:19let's check the load manifest
16:24the plane and the cargo were roughly 280,000 pounds
16:30there was 340 people on board
16:38let's call it 53,000 pounds
16:41and fuel?
16:44fuel was 20,000 pounds
16:47so total weight on landing was 353,000 pounds
16:57give or take
16:59max weight is 424,000 pounds
17:04so
17:12these guys
17:14were 71,000 pounds underweight
17:17it wasn't too heavy
17:19the weight of the plane is not what caused the landing gear to fail on touchdown
17:23what about weight distribution?
17:28you have to have the baggage and the weight distributed properly
17:35so the aircraft will fly the way the pilots want it to
17:39by the book
17:42it was properly loaded, properly stored, properly locked down
17:45so it wasn't really an issue
17:49with weight and balance ruled out
17:53investigators are finally able to test the right landing gear itself
17:59service records are up to date
18:03let's see if the steel wasn't strong enough
18:07another thing they were looking for is any pre-existent weaknesses on the steel
18:15if this occurred in the manufacturing process
18:19it could affect the aircraft in operations all around the world
18:23they perform something called a Vickers hardness test
18:28the Vickers hardness test is an industry standard test
18:31to evaluate the strength of a particular component or piece of metal
18:37a pyramid shaped diamond is pressed into the steel
18:41leaving an indent or dimple
18:43you can measure the depth and the diameter of the dimple
18:48and derive the metallurgical strength of what you're testing
18:52hardness value is 658
18:55so the steel was strong enough
18:58investigators find no weakness in the metal used to make the plane's landing gear
19:04it was determined there was nothing wrong with the landing gear
19:07whatever went wrong it happened before the aircraft touched the runway
19:14there are still no clues that can help explain why the landing gear fractured
19:20the next step in the investigation was to look at how the crew was operating during the last phase of the landing
19:28the landing
19:39this is interesting
19:41official statements made by the pilots may shed some light on the final moments of Martin Air Flight 495
19:46after the accident the investigators came to all three of us we had closed sessions
19:54the captain said the flight was normal the approach was normal at 200 feet we were on the center line
20:05so they should have been okay
20:06but a few seconds later the captain sees lightning
20:11I suddenly felt a high sink rate
20:13it all happened so fast the aircraft actually fell out of the sky
20:18according to the captain he saw lightning just seconds before the aircraft began to lose altitude rapidly
20:25the airplane felt like God took his hands and rammed it into the ground
20:36well get this the first officer stated the weather was bad and it was raining heavily
20:41it was gusty and very turbulent
20:44investigators wonder if sudden wind changes could have contributed to the crash of flight 495
20:50the flight crew indicated to the investigators that they were in an area of with a lot of wind shear a very dynamic weather condition
21:02they were in turbulence things were changing very rapidly
21:06did the pilot encounter wind shear on final approach
21:10the team interviews the air traffic controller to better understand the conditions the pilots were experiencing
21:18can you tell me what happened was flight 495
21:22everything seemed perfectly normal
21:25they were on their final approach and confirmed they had the runway in sight
21:30then I cleared them to land
21:33the wind one five zero one five knots maximum two zero
21:39the controls were quite confident that they performed well the tasks
21:49so they didn't find that they did anything wrong and they gave the correct information
21:54did they report any issues with the plane
21:58no not at all
22:00what about the weather
22:01there was rain but other planes were taking off and landing without difficulty
22:12just minutes before the crash the controller was in contact with an aircraft that took off and another that landed on the same runway
22:23clear to land runway one one one
22:26neither flight reported extreme weather over the runway
22:31what about wind shear
22:35did the runway sensors pick up anything
22:38Faro Airport is equipped with two anemometers that measure both wind speed and direction
22:45located on runway two nine and runway one one
22:49if the anemometers detect a sudden change in wind speed of 15 knots or greater a wind shear warning is automatically triggered
22:59yes there were winter warnings
23:04but they happened after the aircraft had already crashed
23:19if flight four nine five was hit by an extreme gust of wind before it crashed to the runway the system would have detected it
23:29it didn't
23:30there was a conflicting information between what the crew said and what the air traffic controller reports
23:38the crew's statements don't match the controller's account of the weather
23:43thank you
23:48the best thing to substantiate what went on
23:52was to take a really deep look at what the pilots were saying to each other in the cockpit
23:56let's start with their approach brief
24:03a week after the crash of flight four nine five data from the cockpit voice recorder is ready to be reviewed
24:10let the approach with 50 flaps
24:14you call approaching minimums and field in sight
24:17you look outside
24:19wet runway
24:21here are the wipers
24:23Roger
24:25as the crew prepares for the approach
24:28they become aware of weather conditions at Faro Airport
24:30you have to make a positive landing
24:34yes
24:36okay
24:38so obviously they're worried about the runway conditions
24:42in a positive landing the aircraft touches down firmly enough to penetrate the water
24:48allowing the wheels to grip the tarmac and slow the airplane
24:55they want to put it down hard to avoid hydroplaning and running out of runway
25:01so what went wrong
25:03did the pilots somehow botch their plan as they approach the runway
25:06500
25:13cleared
25:15speed a bit low
25:17speed is low
25:19low
25:21okay
25:23now speed is an issue
25:26going onto a wet runway
25:28going onto a wet runway
25:30the airspeed control is very very important
25:33so that you don't have too much in the airplane floats
25:36but that you don't have too little and you end up impacting the runway quite hard
25:41alright let's hear more
25:43speed is okay
25:45windshield anti-ice
25:47I can't see anything
25:49wipers are on fast
25:51as the plane gets closer to the ground the crew contends with stormy conditions
25:56a bit low
25:59low
26:01yes
26:05throttles
26:15why does the captain yell throttles
26:20for the captain to say this at this moment it raises the question
26:23did they have an issue in the final phase of landing
26:28alright let's look at the descent profile
26:31if flight 495 flew in on the right trajectory the FDR will confirm it
26:36here you go
26:38the flight data recorder gives objective clear data on what the airplane was actually doing
26:45was the airplane being flown at the proper speed
26:48the changes in the airspeed were they indicative of a severe weather condition and how were the pilots responding to those changes
26:59autopilot is on okay so they're descending at the standard angle and they dip here and recover
27:11looks fine
27:12looks fine
27:15at 200 feet which is about 20 seconds from landing they were on a normal glide path
27:23something happened between that and touchdown
27:28let's look at the airspeed data
27:34so looks like they're flying steady at 145 knots until here
27:40and airspeed jumps
27:42and then drops all the way to 139 knots
27:45investigators spot evidence of airspeed fluctuations during the last minute of the flight
27:55these fluctuations in airspeed can be caused by wind gusts as they get closer to landing
28:01speed is a bit low
28:08speed is low
28:12speed is low
28:20speed is okay
28:21was the captain concerned their speed wasn't fast enough to compensate for the strong headwind
28:32these fluctuations seem too extreme to be caused by the 20 knot winds reported by the controller
28:38we need a full analysis of the weather conditions on final approach
28:41investigators ask the Netherlands Aerospace Laboratory to perform an in-depth weather study to determine if the winds were stronger than what was reported to flight 495
28:56what about auto throttle data
28:59let's take a look
29:00yeah the fluctuations in auto throttles correspond to the airspeed fluctuations
29:18if there is an increase in airspeed the auto throttle system will decrease the power that is being commanded the amount of thrust that the engines are producing
29:27if the airspeed falls low
29:31the auto throttle system will command increased thrust to bring the airplane up to the commanded airspeed
29:39the auto throttles were indeed adjusting for the dramatic changes in airspeed
29:45wow look at that
29:47102 percent power
29:49investigators discover a very high surge in engine power three quarters of a mile from the runway threshold
29:55the 102 percent command by the autothrottle system is a massive amount of power it would be similar to the amount of power that you would use for takeoff
30:06too much power to try to land with
30:09and then here power drops to 40 percent
30:13the team discovers that the power drops to a minimum or engine idle shortly thereafter
30:20that's way too fast for the autothrottle system to perform on its own
30:25for the engines to decelerate as quickly as they did
30:31means that the levers were moved faster than the autothrottle clutches can physically move them
30:37the only way the throttles would move that quick would be if the pilot was manually adjusting them down to 40 percent
30:48the autothrottle system could make large corrections and you have to make manual adjustments if the throttles aren't keeping up
30:54the first officer who's a flying pilot made the decision to override the autothrottle system and to pull the power way back
31:10and in fact he pulled it all the way back to flight idle
31:15with so little power they would have dropped like a rock
31:20according to the data they were dropping a thousand feet per minute
31:25one thousand feet is well beyond the operational limit of 600 feet per minute for the DC-10
31:32as a consequence of the reduced power the plane hit the runway with enough force to crack the landing gear
31:42i've never experienced a landing as hard as that
31:45i crushed my teeth and my mouth
31:50it was hard beyond compare
31:53investigators are left with a key question
31:57why would the crew reduce power by so much
32:01so far from the runway threshold
32:03this is the Dutch weather report
32:16investigators turned to a weather analysis prepared by the Netherlands Aerospace Laboratory
32:21to determine if the weather affected the crew's actions during their final approach
32:26looks like the weather was worse than we thought
32:28really?
32:30they hit no less than three separate microbursts in the last minute of flight
32:36wow
32:37okay
32:39a microburst is a column of air that descends from rain clouds
32:44hits the ground and fans out horizontally
32:48it leads to significant fluctuations in a plane's airspeed
32:51when exactly?
33:01the first one was at 700 feet
33:06the second was between 600 and 300 feet
33:13and the last one was between 200 and 110 feet
33:18now this last one was the worst
33:26the wind speed jumped from the reported 20 knots
33:31to 40 knots
33:33wow
33:35that would have triggered a wind shear alert
33:37if one was installed on the plane
33:39then the wind shifts from a headwind to a tailwind
33:42a sudden shift from headwind to tailwind
33:47a sudden shift from headwind to tailwind
33:49is the worst type of wind shear
33:51because a headwind improves your angle of attack
33:54to ensure that the aircraft has good lift
33:57when the wind switches around to a tailwind
34:01you lose that aerodynamic performance
34:04if you don't have the thrust to compensate for it right away
34:07the aircraft will drop
34:10let's compare this to the autothrottle data
34:14they line up? mm-hmm
34:29for every microburst there's a corresponding increase in engine power
34:32as the autothrottles try to maintain the plane's speed
34:37the autothrottle was going up and down
34:40it was struggling very hard to fight against those heavy downbursts
34:45the downburst causes a decrease in stability
34:50which means turbulence induced roll and pitch oscillations
34:54would have been a bumpy ride
35:00yeah
35:02as they passed through each microburst
35:05the autothrottles were adjusting to the shifts in wind gusts
35:08in the final moments the approach was under extreme weather conditions
35:26there were a lot of oscillations in speed
35:29and that created a lot of stress for the pilot flying at that time
35:32the first officer likely would have been overwhelmed by the unexpected change in the weather
35:45and knowing that he needed to make a positive landing at the runway threshold
35:50he sees the power spike to 102% and takes corrective action
35:56in order to get the plane on the ground
35:58the first officer overrides the autothrottle and reduces the power to idle
36:05investigators now see just how unfortunate his timing was
36:10he cut the power at the exact same time that last downburst hit them
36:21throttles
36:22the captain tries to stop the plane's uncontrolled descent
36:28but he's too late
36:33the captain should have stepped in sooner
36:37he should have recognized something was not right
36:42the captain really should have taken over and landed himself
36:46the captain really should have taken over and landed himself
36:49investigators suspect the sudden change in weather
36:53combined with the pilot's decision to cut power too early
36:56caused the aircraft to land with more force than it was built to withstand
37:00but one question remains unanswered
37:05if the winds were gusting at 40 knots a half mile from the runway
37:10wouldn't the winds at the runway be gusting stronger than the 20 knots reported by the controller
37:20the team returns with their findings to the air traffic controller who oversaw Martin air flight 495
37:34you reported that the winds on runway 1 1 1 were gusting up to 20 knots
37:45that's correct
37:48but that doesn't seem right
37:50the Dutch weather study confirmed that there were three microbursts in the last minute of flight
37:52width gusts much higher than that
37:55can you show me the actual data for runway 1 1?
38:01can you show me the actual data for runway 1 1?
38:20according to the raw data
38:23the winds were actually gusting at 35 knots
38:26well that sounds more like it
38:31but how could you have underreported the wind conditions?
38:47we receive wind data every 30 seconds from this device
38:51it must have been switched to runway 2 9
38:58it must have been switched to runway 2 9
39:05instead of runway 1 1
39:11investigators discover that air traffic controllers at Faro airport
39:15had mistakenly selected the wind reading on runway 2 9 instead of runway 1 1
39:24airports are large places
39:26so when you have anemometers on opposite ends of the airport
39:29you would expect that frequently there would be a difference in direction and velocity of a reported wind
39:34Martin air 4 9 5 cleared to land runway 1 1 the wind 1 5 0 1 5 knots maximum 2 0
39:49cleared to land
39:51the controllers information that they provided to the crew was not representative of what was actually occurring on the runway
39:58the runway
40:05wet runway
40:08Crosswinds
40:10that's a completely different picture
40:12if the pilots were aware they would have gone around
40:15investigators have figured out what brought down flight 4 9 5
40:20report down flight 495.
40:29495 is turning inbound.
40:33495 copy.
40:34Report at minimums or runway in sight.
40:37Runway surface conditions are flooded.
40:40Roger, 495.
40:48You're down.
40:51Gear down.
40:53With the runway at Faro underwater,
40:55the crew plans a positive touchdown at the runway threshold.
41:00Clear to land runway 1-1.
41:02The wind, 1-5-0, 1-5 knots, maximum 2-0.
41:08But they're unaware of the severity of the weather conditions.
41:12I can't see anything.
41:13I'm on it.
41:16They're hit by a series of unexpected microbursts.
41:21Causing the engine power to shoot up automatically.
41:26Concerned that the excess power is too great for a positive landing.
41:31The first officer reduces the power to idle just as the last microburst occurs.
41:36That makes them vulnerable to strong winds.
41:40And the aircraft dropped from 150 feet.
41:43Flight 495 slams to the ground at 1,000 feet per minute.
41:49The danger of being slow and encountering a downdraft is you may not be able to recover in time and that can be disastrous.
42:02They could have come with a higher speed.
42:03They could have performed a missed approach.
42:04But the truth is the flight crew tried their best.
42:08This wasn't an accident where we can see negligence or gross error.
42:18In the aftermath of their report into the crash of Martin Air Flight 495, investigators make a series of recommendations.
42:31This accident was going to be yet another example of inappropriate wind shear recovery being applied in a timely fashion.
42:52So this is additional pilot training.
42:57This is wind shear detection systems on airplanes.
43:02This is a more aggressive approach to go-arounds in unstable conditions.
43:07Shortly after the crash, Faro Airport modernized their wind sensors and displays to comply with international regulations.
43:18The critical information that controllers provide to pilots needs to be accurate.
43:25So these are some of the lessons that the industry learned and implemented following this accident.
43:31You know, one of the things I was told when I was coming to pilot is never let your guard down.
43:39You can be having a beautiful, wonderful flight and in the blink of an eye, things can change.
43:46It's just ingrained in my mind.
43:49Always be ready for the unexpected.
43:51You can be ready for the unexpected.
43:52You can be ready for the unexpected.
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