- vor 2 Tagen
On 12 November 1995, American Airlines Flight 1572 clips the tops of trees along Peak Mountain Ridge and strikes instrument landing system equipment on landing at Bradley International Airport in Windsor Locks, Connecticut. All 78 people on board survive, with one passenger sustaining a minor injury.
Kategorie
📚
LernenTranskript
00:00on approach during a thunderstorm both runways are wet severe turbulence American Airlines flight
00:091572 loses a valuable lifeline there's a leaky window in the tower the tower had actually been
00:19abandoned this is a very unusual situation NTSB investigators learned that a supervisor went to
00:25the deserted tower I told them they could land landing is at your discretion the runway doesn't
00:31appear to be clear moments before touchdown disaster strikes and both of the plane's engines fail what
00:40role did an out-of-service tower play in jeopardizing the lives of the 78 people on board tell them we're
00:46on down on a stormy November night American Airlines
01:16flight 1572 cruises 35,000 feet above Pennsylvania smoother right up here than at 33,000 captain
01:29Kenneth Lee a former military pilot has been flying with American Airlines for 10 years that's for sure
01:36first officer John Richards also flew with the military and has seven years of commercial aviation
01:43experience this was a very experienced flight crew that was very comfortable with the aircraft they
01:50were flying they're flying the MD 83 a twin-engine narrow-body jet it has two turbofan engines mounted
02:00in the tail as a t-tail and a swept main wing it was one of the last aircraft that actually had direct
02:08connection between the controls and the cockpit and the services on the airplane better get the cabin
02:15ready for our descent hi we're starting our descent now so you can lock the cabin up and prepare for landing
02:24will do please fasten your seat belt it's a short two-hour flight from Chicago's O'Hare Airport to Bradley
02:39International Airport at Windsor locks Connecticut there are five crew and 73 passengers on board many of them
02:47returning home please put your seat in the upright position
02:54flight started out rather routinely it was the second day of a three-day leg trip for these guys
03:00American 1572 to send a pilot's discretion maintain flight level one nine or zero
03:07discussion to one nine zero American 1572 let's go down the flight is 25 minutes from landing I'm gonna
03:19get the 80s real quick 80s or automatic terminal information service provides pilots with important
03:31airport data like weather and approaches both runways are wet severe turbulence all right sounds like it's
03:44gonna be a bumpy ride tell the passengers they'll encounter some rough weather along the way but
03:50nothing this experienced crew can't manage many times I have experienced the same kind of winds and
03:57weather that this crew has had and the winds will have a drastic effect on the airplane and pushing it
04:02around the crew was very familiar with the weather and they were highly experienced enough to handle anything
04:07we've started our descent and right now they've reported some moderate turbulence on the descent so
04:14it might get a little choppy just watch me the whole way yeah man you got it the pilots prepare for the
04:24landing any comments just scream out you're gonna get a lot of turbulence you know how to land it they support each
04:35each other they back each other up if anything goes wrong or somebody does something wrong the other
04:40one catches it and corrects it 50 miles from the airport the weather worsens it's a lot of rain I can
04:49see that the in route controllers had told them the weather was gonna be bad due to thunderstorms and wind
04:57shear wind shear is a sudden change of wind speed or direction that can be dangerous close to the ground
05:04American 1572 descend and maintain 4,000 to setting 4,000 flight 1572 is the last plane flying into Bradley
05:19Airport tonight approaching 4,000 the crew is making a difficult non-precision approach a non-precision approach
05:31which means that you don't have a navigation aid there's more reliance on the crew to figure out
05:37the altitude and to send those out to correctly and avoid all the terrain that's below there we're
05:43established on the inbound track for the VOR approach flaps five check that's five this type of
05:54approach creates extra work for the pilots the non-precision approach is the hardest of all the
06:00approaches to fly because it takes so much attention to fly the approach it has to be set up correctly
06:05the tower is closed at this time due to a problem with one of the windows the non-precision approach
06:15and rough weather aren't the only challenges facing the crew copy there's a leaky window in the tower at
06:28larger airports the control tower has two areas for managing incoming and outgoing flights approach
06:35control typically located on one of the lower floors and tower control at the top mark Guillo was the air
06:44traffic manager at Bradley Airport for 12 years once they're within five miles of the airport the
06:50approach controller turns them over to the tower to bring them in for landing and taxi into the gate
06:54but a leaky window has shut down the tower forcing the air traffic controller to leave her post
07:03the tower controllers are the pilots eyes on the ground they're the ones that ensure that the runway is
07:11sterile and clear for them to land on that there are no obstructions no other traffic they also
07:17provide critical information in the late stages of the flight flaps 11 please you got it the pilots must
07:30now rely on their own observations to land safely the pilots were expecting someone to be able to be in
07:40the tower the controller to see the condition of the runway and to give them the information needed to see
07:46if anything during the thunderstorm had blown onto the runway so they can make a safe landing the approach
07:53controller is closely monitoring the flight he notices the plane is veering off course American 1572 looks like
08:02you're a bit to the left of final yeah it looks like we're left of it copy seven miles from the airport
08:12captain lee gets the plane back on course so gear down gear down
08:23I'm going up to the tower the supervisor in approach control volunteers to give the crew of flight 1572 some guidance
08:40American 1572 there is someone in the tower it's not officially open but you can change the tower frequency
08:49it would have been a big relief to the crew to have someone in the tower the controller up there to give
08:58them the information they need for the approach hey tower American 1572 we are six miles from runway one five
09:08landing is at your discretion the runway doesn't appear to be clear copy
09:14any landing is really at the pilot's discretion but in this particular case they need to be extra vigilant because
09:22they did not have any official tower assistance flaps 40 the pilots configure the aircraft for landing
09:31flaps and slats to 40 40 you are clear to land
09:40there's a thousand feet okay
09:45flight 1572 is just 60 seconds from touchdown
09:52what the bells and whistles were going off lights were flashing and something had to be done
10:04two and a half miles from bradley airport in connecticut american airlines flight 1572 has struck
10:10something while descending to the runway the pilots must act quickly to avoid crashing go go around going around
10:17they pull the nose up in an attempt to recover flaps 15 positive rate gear up
10:29gear up the crew immediately began a grow around procedure they raised the gear raised the flaps cram
10:37the engines forward and immediately after that things went downhill very quickly
10:47left motors failed seconds after the pilots commence the go around the plane's left engine loses power
10:57that's the last thing you need to have happen is a power failure on one of the engines
11:02there's the runway straight ahead
11:05okay tell them we're going down tell them emergency okay tower a call for emergency equipment we are going down on the runway
11:13looks like we've got an emergency on 1572 send the trucks emergency vehicles have been dispatched
11:24as the pilots prepare for an emergency landing the situation worsens the right engine also fails turning
11:32the md-83 into a 60-ton glider they realized they had the second power failure which made double trouble
11:40without its engines the plane has drifted further off course captain lee tries to line it back up with
11:47the runway you've got it dude you're gonna make it but they may not have enough lift to reach it
11:55a stall is an aerodynamic effects it's when the wings lose lift and the airplane loses directional control
12:02the only way to fly out of a stall is max power which they did not have
12:11hold on guys
12:16hold it down buddy hold it down hold it down hold it down hold it down
12:22hold it
12:37god bless you you made it
12:39it was a miracle that the first officer saw the runway and the crew reacted so quickly it was a
12:49very good reaction and uh certainly saved a lot of people's lives flight 1572 has landed safely
12:57after a treacherous final approach
13:02everyone has survived and remarkably only one person has suffered a minor injury
13:09the pilots are hailed as heroes for saving their plane and everyone on board
13:16one of the key things about something like this is that you never stop flying the airplane
13:20and those who do don't live to tell about it
13:27the events that nearly brought down flight 1572 are a complete mystery what have we got so far
13:36it will be up to investigators from the national transportation safety board or ntsb to find the
13:42answers bob benzen heads up the team i was the investigator in charge with about a dozen ntsb
13:49people underneath me plus many people from the industry the aircraft hit the ground hard approaching
13:56the runway threshold
13:59maybe the engines had something to do with it
14:02did a loss of engine power cause flight 1572 to crash land in front of the runway threshold
14:11when we first arrived at the accident site our first order of business really was to kind of
14:15do a reconnaissance look at the aircraft this thing looks like it flew through a war zone
14:23during our initial examination the aircraft was very very damaged it reminded me of something like
14:29a b-17 that had gone through a raid on schweinfurt in world war ii it was beat to heck
14:38branches sticking out of the landing gear engine blades missing battered flaps
14:43the aircraft was unflyable they definitely hit some trees oh they sure did and the engines definitely
14:53had power and they shredded those branches mangled branches in the plane's engines indicate that they
15:00were working normally the discovery raises another question if the engines had power why'd they hit the trees
15:13the main question became why the aircraft was low enough to hit trees and still make it to the runway
15:22if you're going to analyze an accident like this which is be categorized as a controlled
15:27flight in train you have to understand where the airplane went and when it went there and why it went there
15:31where exactly did they hit the trees to understand why flight 1572 struck trees investigators try to identify
15:51the first point of impact the trees they hit are on top of a ridge about two and a half miles northwest of
15:58the runway we have a team out there now let's see if the trees or the ridge were marked on the chart
16:04the approach chart itself when you look at it had the ridge marked with a small dot with the altitude
16:11the chart has the top of the ridge at 819 feet once we get a look at the approach chart itself that
16:18the crew was using we noted that the ridge line was just a mere dot with the number 819 next to it
16:25an altitude that dot could have been anything it could have been a building a giant tree
16:30other airlines use a slightly different chart that shows topographical features including this ridge
16:35line did flight 1572 come in too low because there was a lack of detail on their approach chart
16:42do we have an altitude for the tree strike i need an altitude for the first impact mark
16:59771 feet they shouldn't have been anywhere near those trees the team is surprised to discover that when flight
17:071572 hit trees it was 48 feet below the altitude listed for the ridge line they weren't just below the ridge
17:16they dropped 309 feet below the minimum descent altitude
17:25the minimum descent altitude or mda is the lowest altitude a crew can descend to until they are able to
17:32see the runway it's designed to keep planes above terrain or obstructions those altitudes are hard
17:42altitudes when the fa builds those altitudes in there they have to take in consideration of all the
17:48clearances the trees the elevation to keep the airplane at a safe altitude why would they drop so low
17:54maybe there was something wrong with their altimeters
18:02the investigators see the airplane descended too low so the question is did the crew have the correct
18:06indication let's see if the static system is working peo static system was quite important
18:12because that system controls altitude altimeters it controls air speed indicators
18:20it also controls the vertical velocity indications did sensors provide incorrect data to the plane's altimeters
18:34the md-83 has three sets of sensors on the exterior fuselage they measure air pressure to determine air
18:42speed altitude and vertical speed if one of the static sensors is leaking or obstructed it can give
18:50pilots inaccurate information making them think they are above or below their actual altitude
18:57if the pitot tube is is clogged you lose those vital instruments
19:04and that can happen from a variety of reasons
19:09pitostatic systems have caused problems before problems severe enough to cause crashes
19:14the test forces air into the sensor to determine if the air pressure is being measured accurately
19:32but it proves to be a dead end the static system is working
19:35well then let's see what the controllers can tell us
19:42it's always valuable to be able to speak to the air traffic controllers after an accident
19:46often the air traffic controller is the last person to speak to the uh the crew uh prior to an accident
19:54did the crew report anything unusual on their descent into winter locks no no it was a standard
19:59approach but the weather conditions weren't great at the time were there any down drafts did strong winds
20:06push flight 1572 into the trees if an airplane encounters severe down drafts it could push the airplane
20:14down several hundred feet wind shear poses a danger to aircraft in 1985 a severe downdraft slammed delta
20:23airlines flight 191 into the ground more than a mile short of the runway in dallas texas
20:31a hundred and thirty seven people lost their lives
20:37in 1994 a year before flight 1572's close call in connecticut
20:42u.s air flight 1016 crashed into trees while attempting to land in a powerful thunderstorm in north carolina
20:49it plowed into a residential neighborhood killing 37 people
20:56thunderstorms have incredible wind shear they can have updrafts 200 miles an hour and then you know
21:04half a second later after you pass through that you get a downdraft 200 miles an hour
21:09there's a lot of wind around the airport all night what about when this flight was coming through
21:13there was some wind shear investigators learned that airport sensors registered some downdrafts
21:24we made sure to give them updates like i said it was rough so they knew what they were flying into yes
21:31given the weather conditions at the time and the unstable air investigators were able to determine
21:36that there may have been downdrafts up to three or four hundred feet per minute occurring at the time of
21:41this event so if there was a downdraft these guys would have been prepared for it oh yes it was
21:49possible that wind shear could have pulled the aircraft down into the the trees but a careful
21:56look at the weather at the time uh after that we determined that simply wasn't true was there
22:02anything else out of the ordinary that night besides the weather well the tower was shut down for repairs
22:08at the time the leaky window one of our supervisors went up to make sure they landed okay you mean the
22:14tower was down during their approach yes i'd like to speak to the supervisor who was in the tower sure
22:21of course did flight 1572 slam into trees due to a lack of guidance from the tower
22:28air traffic control work is demanding and it's a precise job if if there are any major disruptions
22:39either in the tower or on a radar scope it could affect uh aircraft traffic greatly were there any
22:46signs the crew was having trouble during approach not really it was all normal until they called in the
22:53emergency take me through what happened they were already six miles out line up with the runway the runway
23:01looked clearer so i told them they could land we are six miles from runway one five
23:08landing is at your discretion the runway does appear to be clear copy
23:12did you give them an actual clearance for landing the tower was closed i can only give advisories
23:23it's up to them to decide after that if they want to land advisories are just information provided to
23:29the pilot for their own use um they can they can listen to it they cannot listen to it it's up to them
23:35in this case the tower was not open so therefore he didn't have authority to issue a landing clearance
23:40investigators still don't know if poor weather and a closed control tower caused the pilots to drop
23:47below the minimum descent altitude and into the trees
24:02let's start it at 12 53 when the crew contacts the tower
24:05investigators turn to the cockpit voice recording of flight 1572's final approach
24:14to determine why the plane dropped too low and flew into trees
24:22landing is at your discretion the runway does appear to be clear and what are you showing right now for
24:28winds one seven zero at two four copy he's checking the runway giving them weather updates it's all the
24:39job so far the team listens to the supervisor giving the crew guidance to help them land
24:46it was a good initiative for him to do that it was something some people would not have done based
24:51on the fact that the the tower itself was a bit of a precarious area flaps 40. flaps and slats to 40 40. you are
25:04clear to land okay give me a thousand down one thousand down you got it stop that
25:15a thousand feet a minute no way as they neared the ground the crew decided to make their final descent
25:24at a thousand feet per minute nearly double what is normal
25:31that in my mind is quite excessive you didn't have to descend that steeply
25:36especially on a non-precision approach where you have a minimum descent altitude that you
25:40should not be going below the faster you're descending um the earlier you have to start
25:45leveling off or else you end up going below the target altitude by the time you correct and and
25:50come back up again according to the descent profile they're five miles from the airport at 1900 feet
25:58using the radar beacon data from air traffic control investigators track flight 1572's cockpit
26:05conversation throughout the descent at a thousand feet per minute they're below their mda in less than
26:13a minute sure that's fast but the first officer should be calling out the altitudes while the aircraft
26:19is sending the pilot is supposed to monitor the airplane's mda minimum descent altitude the first
26:24officer should call a thousand above the mda to the captain and then 100 foot to the mda and then the mda
26:32altitude okay let's listen to the first officer's call out there's a thousand feet good he made a thousand
26:45foot call out but they don't hear any more call outs after that the first officer called out the thousand
26:54foot above the mda he did not call out the hundred foot above the mda investigators then hear
27:01something unusual
27:06a thousand eighty is your uh right
27:11you're going below your uh your
27:19hang on was that the minimum descent altitude call out i think it was supposed to be
27:26the team discovers that the first officer mishandled the remaining call outs
27:32the first officer started to call out for the mda but never finished his sentence
27:38so he makes half a call at their minimums and then doesn't say anything else until they're below it
27:44and by then they've hit the trees why did the pilots make such a critical error so close to landing
27:51let's talk to the pilots in this particular case we were very fortunate to have a live crew to
28:00interview we wanted to determine exactly what they were thinking about during the accident
28:04walk me through your actions four miles from the airport as you approached minimum descent altitude
28:15look the weather was rough we were two hours late departing i was monitoring the instruments
28:19and then we were going below your uh
28:25a thousand eighty is your uh right
28:30okay and then what
28:31as we got closer to the minimum descent altitude
28:37i looked outside for the airport
28:41and when i looked back we were below minimums
28:47you're going below your
28:52during that time he was looking out he was not monitoring the flight gauges as closely as he should
28:57have been in this case the appropriate procedure would have had the first officer glued to the altimeter
29:03and the compass and other instruments in the cockpit until the captain said i see the runway
29:11why didn't you call for a go around well there was no time we immediately hit the trees
29:18what the
29:22it was a stressful night
29:23there could be a bit of task saturation in there this went from an easy kind of relaxed flight with
29:32a little bit of weather difficulty to oh my gosh everything's going wrong really really fast
29:42something doesn't add up the first officer couldn't have been at his minimum seconds before hitting the trees
29:48maybe there was an issue with the altimeter settings
29:50pilots must calibrate the altimeters based on outside air pressure
29:57which can change dramatically in extreme weather conditions
30:01pilots frequently recalibrate the altimeters
30:04to maintain an accurate altitude reading
30:08altimeter settings is very important you can't do an approach in bad weather unless you know what the altitude of your airplane is
30:13let's see what settings they used
30:21it's a lot of rain i could see that in this case because of this stormy that was going through that
30:27area the pressure was falling rapidly and when that happens your altimeter setting goes down
30:31quickly it means if you don't reset your altitude then your airplane is flying lower than you think it is
30:36here the dispatcher updated them with an altimeter setting of 29.23
30:50ntsb investigators check whether the pilots of american airlines flight 1572
30:55properly set the altimeter during the stormy approach into bradley airport what time was that 12 30 a.m
31:07that was 25 minutes before they hit the trees
31:10and with changing weather conditions they must have received an update from bradley atc
31:14well one thing that the crew considers and expects from the tower our air traffic
31:21is the update of the weather as as quick as possible so they can also amend what they need to do
31:27okay they first contacted approach control at 12 43
31:33bradley approach american 1572 we are at 11 000 feet
31:38investigators expect the approach controller to give the crew a weather update including the altimeter
31:44pressure setting
31:45the approach control issue the altimeter setting on initial contact when an arriving aircraft enters
31:51their airspace the altimeter is displayed as a digital um display in the control tower as well
31:59american 1572 bradley approach roger expect vor runway 15 approach
32:07but the update is never provided
32:09approach did not update their altimeter setting even though the pressure was dropping rapidly
32:17there's nothing at all from approach right up until he passes them off to the tower
32:22why wouldn't the approach controller give them a weather update good question let's ask him
32:29one thing that puzzled investigators was why the uh air traffic controllers in the bradley tower didn't uh
32:36keep the pilots updated with the current altimeter setting you mentioned before that the weather
32:40was quite active that night yes i was changing quickly all night what was the airport's altimeter
32:46setting at the time of the accident let me see 29.15 investigators learned that the altimeter
32:56pressure setting at the time of the accident was not the setting the pilots were originally given
33:01why didn't the crew receive an updated setting um 29.15
33:17i didn't think to give it to them
33:23sometimes things that you do over and over and over again uh become
33:28um too routine and um late at night when there's not a whole lot going on sometimes those are the
33:35things that drop through the cracks we learned about that uh that excuse a little bit but it's what he
33:42said so in essence the pilots did not have the current altimeter setting when they flew the approach
33:49we got the altimeter setting from the time of the accident
33:52comparing the two altimeter settings will reveal how much lower the plane was flying than it should
33:59have been 0.08 the difference in the altimeter setting from what they had put on their uh instruments
34:08to what was reality was about 0.08 inches of mercury which equates to 76 feet because of the pilot's
34:15outdated setting they thought they were 76 feet higher than they actually were
34:20the discovery is eye-opening once you get close to the ground 76 feet is a big deal
34:28once you're coming across the minimum descent altitude and you're keeping the airplane level
34:32at the minimum descent altitude 76 feet is critical the question is would they have hit anything had they
34:38been 76 feet higher well we know they struck the trees at an altitude of 771 feet add 76 feet to that
34:48they wouldn't have hit anything no impact if they had the correct altimeter setting um even though they
34:54went below the mda they still would have been 76 feet higher um and we probably wouldn't be talking
35:02about this right now because they would have missed the trees but that doesn't explain why there were 309
35:07feet below their minimum descent altitude 76 feet of that are on atc the other 233 feet are pilot error
35:17this was out of the control of the pilots to a certain extent but going below the mda
35:23should have been caught by both the first officer and the captain this is what created the accident
35:28in the end it came down to the crew's decision investigators now understand what happened to flight 1572
35:43the outdated altimeter setting and the rough weather meant that the crew had almost no room for error on
35:48the approach and when they were descending too fast and past their minimum descent altitude
35:52there was no way they could recover before hitting the trees only one question remains unanswered
36:01in spite of hitting the trees how did they make that landing
36:04here's the fdr read up
36:19ntsb investigators turned to flight 1572's flight data recorder
36:24to learn how the crew managed to recover their jet after they struck the trees
36:29so they hit the trees and they immediately pull the flaps back to 15 and go to max thrust
36:39the data shows that the crew quickly configured the plane for a go around go go around going around
36:46the aircraft actually ingested trees the tops of the trees into
37:16the engines left motors failed followed by their right engine
37:26here you have a scenario where something devastated just happened we just plowed through some trees on
37:31the top of a ridge two and a half miles away from the runway and losing capabilities on this aircraft
37:36by the second they've got the nose way up they're losing speed and both their engines are gone
37:42that's a recipe for a stall if i've ever seen one all of a sudden they were starting to lose airspeed
37:48they were in a nose-high attitude and that's the worst time that could happen airspeed is what makes
37:53the airplane fly if there isn't enough air moving over the wings the wings stop flying and that is
37:59what's referred to as a stall there's a runway straight ahead
38:05fortunately the first officer saw the runway they had to get the airplane on the ground in a hurry
38:10because they would not be able to keep on flying with the engine power they had
38:13okay tell them we're going down tell them emergency so now he's got to reconfigure the
38:19aircraft again and remember this is all happening in seconds he's got to focus on trying to save whatever
38:24altitude and airspeed he has left to make it across the fence and to the runway environment
38:30this is a critical stage of flight now because he doesn't have power all he can do is trade altitude
38:35for airspeed now we know their flaps we're all the way down at 40. flaps 40 all the way down they're all
38:43the way down he's going to generate something else that's going to get him across the fence and that's
38:48when he drops 40 degrees flaps the drag from the flaps slows them down but for the first few seconds
38:54it balloons them up 40 degrees of flaps change the curve of the wing which increases the lift of the
39:01wing and gives him that that extra little bounce to get a little bit further if he had not have done
39:09that or if he would have delayed it a little bit uh the accident could have been totally catastrophic
39:15you've got it dude you're gonna make it they glide down to the runway unfortunately they didn't have
39:24quite enough airspeed and altitude so they landed early kind of scooted and flopped onto the pavement of
39:30the runway they made mistakes going into the tree strike if you will and yet did a brilliant job landing the
39:45aircraft that's an incredible show of airmanship the crew's actually excellent cockpit resource management
40:00in the very difficult situation that occurred after they hit the ridge line uh they cooperated uh they
40:06didn't panic the way these two pilots worked together was was remarkable and one of the last things that's
40:14on the tape that kind of really gives you a chill is is after they make the runway the first officer
40:19says god bless you you made it this is an accident that probably is not well known to a lot of people
40:29and that's because the aircraft was able to end up on a runway and nobody was killed
40:34the captain's impressive recovery doesn't make up for the crew's errors the ntsb's final report
40:43concludes that the probable cause of this accident was the crew flying below the minimum descent altitude
40:49before they could see the runway
40:54we think in essence the main factor involved in in the accident was the fact that the pilots did not
41:00monitor the altitudes they were flying through correctly they they should have level off at a
41:06point and they simply did not do so following the accident american airlines increased the mda requirement
41:13by 100 feet and visibility requirement by half a mile for non-precision approaches to bradley airport
41:21a lot of rain the ntsb also recommends that in conditions where pressure is falling rapidly
41:28controllers should issue altimeter setting updates as frequently as possible the approach controller
41:35issues the current altimeter setting that didn't happen either right what's important to understand
41:40though in terms of uh responsibility is that the the captain is the final authority on the flight
41:46it's ultimately the captain's responsibility to ensure the safety of the flight in this case he did
41:52not ensure that he had the most current altimeter setting this accident was important to me uh because
41:59it was one of the few where nobody was killed nobody was hurt and yet uh the safety board came up with
42:06some pretty good recommendations to mitigate some of the factors that existed