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00:02The plane came flying out of the bottom of the cloud at 4,000 feet per minute.
00:06Pull up! Pull up!
00:07Nuremberg Air Service Flight 108 breaks apart
00:11while the pilots attempt to land at Dusseldorf Airport in Germany.
00:16All passengers and crew are killed.
00:21Because of the size of the accident site,
00:24we use the grid to identify the positions of every part of the wreckage.
00:31Investigators reconstruct the plane to determine what happened.
00:35There must be a thousand pieces in here.
00:41Over here.
00:42They uncover evidence of a one-in-a-million failure
00:45that should not have brought the plane down.
00:48The pilots had no chance to control the aircraft in a proper way.
00:54I think under these circumstances, there was nothing they could have done.
01:00D-Day, D-Day.
01:04Pull up!
01:07I need one-zero, for having you on train here,
01:09I'm on the line, I'm on the line, you're on the line, you're on the line, you're on the line.
01:10You're on the line, you're on the line.
01:15You're on the line.
01:23It's an hour before sunrise at Hanover Airport in West Germany.
01:31Nuremberg Air Service Flight 108 prepares for the first flight of the day.
01:42in the cockpit is 36 year old captain ralph borstorff how's the weather looking and 28
01:50year old first officer sybil hailman they each have 2 500 flying hours should we clear sailing
01:59both of them would be fairly typical what you would see in commuter operations people starting
02:05their careers and getting ready to move up the weather forecast predicts calm skies with only
02:12a slim chance of thunderstorms near their destination might get a bit rough on landing
02:17because of some turbulence and a chance thunderstorm but it's unlikely just 10 sounds good
02:26a 10 chance of thunder showers it's 10 chance you want to know about it but it's not something you're
02:32going to put too much thought into before flight 108 can depart snow and ice that accumulated overnight
02:40are removed this flight was a full flight had 19 passengers on board all of those being business
02:49people it's a 40-minute flight from hanover to dusseldorf a major business hub on the rhine river
02:57we started the route in 1987 about six months before this flight we had very weak train connections
03:06between the east and western parts of germany so from the very very beginning we had full airplanes
03:14flight 108 leaves hanover at 7 15 a.m 15 minutes behind schedule flaps
03:28we're attracted the pilots are flying a fairchild swear engine metroliner three it's a powerful
03:36turboprop plane designed for short commuter flights the metro three airliner is a perfect scaled down
03:43airliner it holds 19 people fast fuel efficiently all the creature comforts of a bigger airline
03:49from the very beginning i was impressed by the airplane it was extremely well designed it was flexible
03:58it was fast they could pressurization so everything a pilot likes the airplane had
04:08it takes 10 minutes for flight 108 to reach its cruising altitude of 14 000 feet
04:16it will stay at that altitude for only 15 minutes well no rest for the wicked we'll have the descent
04:26checklist
04:27will you regional flying is generally an hour and a half or less um leading to increased workload for
04:35the time of the time that you are in the air check the radar the captain notices some weather on
04:44the radar
04:46thunderstorm could be rolling in after all maybe doesn't look particularly bad i'll check the atis
04:57ATIS continuously broadcasts updated weather conditions at the destination airport
05:03one two gusting two four visibility 10 sky condition broken clouds at 1500 feet
05:11nothing but a thunderstorm we should be fine
05:16okay we'll continue with the approach their expectation was that the weather was getting
05:22better and that any thinner showers hadn't really materialized good morning this is your captain
05:27speaking we have begun our descent into dusseldorf please ensure your seat belts are fastened should be
05:34landing in about 15 minutes
05:4430 miles from the airport dusseldorf good morning requesting to send a 3000 nfd 108
05:52first officer hailman contacts the dusseldorf approach controller for landing instructions
05:58nfd 108 good morning to you you are cleared to 3000 feet and currently number three to land
06:06copy to send to 3000 number three to land
06:10when atc gives us a indication of where we are in the order for landing it helps us set up
06:15it helps us get
06:15ready it helps us know when you're going to start putting flaps and the gear down three minutes later
06:24localizer live
06:27flight 108 lines up with the runway's center line
06:36establish on the localizer
06:40the first officer checks on the weather
06:45looks like a thunderstorm has moved right in front of us
06:50might be trouble
06:55thunderstorms have to be treated with respect i mean they can produce hail they can produce
06:58downdraft tailwinds overpowering what the airplane is capable of doing
07:04the captain decides to maneuver around the storm
07:14the problem was it's a big thunderstorm in the approach sector of dusseldorf they shouldn't fly
07:21through thunderstorms in the dusseldorf control center nfd 108 please switch to tower control frequency
07:30one one eight decimal three zero the approach controller hands over flight 108 to the tower
07:38nfd 108 confirm switch to tower control frequency one one eight decimal three zero bye
07:49moments later flight 108 disappears from radar
07:59seven miles northeast of dusseldorf airport a maintenance worker at a sewage treatment plant
08:06hears the sound of an approaching airplane flight 108 breaks out of the clouds in a steep dive
08:16500 400 400 300 pull up
08:23the plane pulls up just in time
08:28the plane came flying out of the bottom of the cloud at 4 000 feet per minute the g-force
08:32it would
08:32have taken to overcome that to pull the airplane nose back up uh it was violent the sound of the
08:38engines recedes into the distance that flight would have been sheer terror
08:45to your terror for the people in the back your terror up front you know you went from having a
08:48visual
08:49reference to thinking you're good to all of a sudden you're back in the cloud again
08:53a minute later the plane returns this time flight 108 spirals out of control
09:02and breaks up no no no it's a horrifying sight i can't even imagine what the person watching that
09:10would be thinking two minutes before dawn flight 108 slams into an open field on the banks of the ruhr
09:18river
09:26the wreckage is scattered over a wide area first responders make their way to the crash site
09:36all 19 passengers and both pilots are dead the metroliner itself is broken into thousands of pieces
09:46you're seeing that parts are distributed throughout the area you'll start collecting all the parts
09:53mapping where they are and trying to put this puzzle back together again
10:04investigators from germany's air accident investigation unit or fus begin mapping the wreckage of flight 108
10:13to determine what caused the accident the first step was to identify the positions of every part of the wreckage
10:23and because of the size of the accident site we use the grids and we were able to get the
10:30information
10:31where every piece was at the accident site much of the plane along with its black boxes are badly damaged
10:43the recorders in this aircraft aren't the new digital type recorders which record 300 400 parameters
10:51this was the old foil style recorders you had altitude airspeed you had heading some information
10:58at g loads you didn't have the data we have today by a long shot the black boxes and the
11:05debris are sent to
11:06a warehouse where investigators begin their analysis once the parts are recovered taken to a facility
11:16you can then clean where the fractures where the separations are you can look at where a part broke apart
11:25the wings the engines the tail sections separated from the aircraft
11:33investigators try to confirm witness statements that the plane broke up before it crashed
11:41this piece looks compressed like it came from a high energy impact
11:48but this piece is intact
11:52what that indicates is this intact piece of wreckage did not go to the accident site with the rest of
11:59the airplane
12:01for sure an in-flight breakup
12:03the team is now convinced that flight 108 broke up before hitting the ground
12:10the question is what led to that is there any evidence of a pre-existing failure that would have
12:16led to the accident
12:19uh... hey can you uh bring that piece over to the table
12:23did a design flaw or some kind of failure create a fatigue crack causing the wings to break off before
12:31impact
12:33even though the airplane is fairly new you don't rule out anything was there a flaw in manufacturing
12:39was there a full drilled where it shouldn't have been drilled
12:42was there some other issue that would cause a crack to start growing very early in aircraft's life
12:49well this doesn't look like a fatigue crack at all
12:54it can only mean one thing
12:58overload fracture
13:04overload fractures can occur because the airplanes exceeded speed limits
13:08uh... flight control inputs are severe uh... severe turbulence can cause overload
13:15and sometimes you have a combination of all three coming together
13:19hey can you get the lights
13:22what pushed this plane past its structural limits
13:26investigators examined the plane's flight path for clues
13:34nothing unusual here
13:38the flight path from departure
13:41in route to rival for landing
13:44seem normal
13:46what happened at this part the end of the flight
13:53oh look at that
13:56they discover that the pilots flew an erratic flight path before the plane crashed
14:02that would certainly cause a structural overload
14:06agreed
14:08the crew was on approach
14:11and now suddenly goes through some very tight maneuvers
14:15and you piece that together with the wreckage you found and where it was found
14:21and that gives you a much better idea of what led to the accident
14:27investigators speak to the controller who oversaw the approach of flight 108
14:32to determine what might have caused the unusual flight path
14:37tell me about the night of the crash
14:39uh... there was thunderstorm activity from about 7 40 until just after 8 am
14:47mm-hmm
14:49did your other flights run into any trouble
14:51they reported moderate icing and turbulence but everyone else landed without incident
14:58okay
14:59no go arounds no missed approaches
15:02no
15:03okay
15:03no
15:05uh but about six miles out a 737 got hit by lightning
15:14dusseldorf approach
15:15lufthansa 1354
15:18we just experienced a lightning strike at 3000 feet
15:21six miles final
15:22no immediate issues
15:24lufthansa 1354 dusseldorf approach
15:27roger let me know if you require further assistance
15:30typically when we're concerned about thunderstorms in the airport vicinity
15:34it's not much about the lightning it's more about the winds and the wind shears that
15:37can be powerful enough to push the airplane into the ground
15:40since airplanes are made of aluminium which conducts electricity
15:45most lightning strikes flow over the skin of the fuselage and safely exit through the tail
15:51i remember one occurrence of flying the aircraft got hit by lightning
15:54there was a sudden flash outside the fuselage you could hear it and
16:02the airplane kept on going and there was no associated damage to the aircraft
16:07and we continued on did you report the lightning strike to flight 108 yes
16:13nfd 108 the preceding landing experienced a lightning strike about six miles final
16:19dieseldorf approach we copy and are looking outside nfd 108
16:26for flight crews it is not abnormal to deal with thunderstorms and to deal with the probability of
16:32some lightning this flight was very very usual okay great thank you for your time
16:40if it wasn't the weather that caused the pilots to push the plane past its structural limit what did
16:51will flight 108's black boxes provide clues as to why the plane broke up mid-flight
17:00it's not looking good how so
17:07flight data recording and the cockpit voice recording both stopped two minutes before the
17:12plane crashed at the exact same time that the plane started flying erratically
17:19a total power failure the cdr and fdr get their power from two separate sources so the fact that both
17:28these recorders stopped at the same time indicates whatever happened affected both electrical systems not
17:35just the one the metro liners electrical system is powered by two generators in the event of a power
17:43failure two batteries act as a backup system
17:49but if it was a total power failure that means the backup system filled as well
17:55how's that even possible
17:58from the perspective and the explanations coming from the manufacturer
18:02the possibility of a total electrical loss was very low but during the course of the investigation we
18:09understood more and more that it could be that the flight crews had a total electrical loss
18:17investigators consider the effects of a total power failure
18:21they would have lost most of their instruments
18:23well except their vertical speed indicator the altitude and the third attitude indicator
18:32our metro liners have been installed with a third independent
18:39artificial horizon it used bleed air coming from the engine and as long as the engine was running
18:45the artificial horizon was working as well totally independent from electricity
18:51the standby non-electrical artificial horizon could have been used by the crew
18:56to help keep the aircraft level and straight
19:03and then the complexity of this accident gets into why didn't the crew effectively use that standby
19:10but even with limited instruments who's to say they could have even seen them
19:14oh good point the lights that illuminated the instruments may not have been working
19:19huh
19:22you need those instruments and if you can't see them then you don't know if you're up or down
19:25you're flying blind at this point
19:40to confirm the unlikely finding of a total electrical failure the team examines light bulbs from flight
19:47108 instrument panel if the light bulb was on when the plane hit the ground the hot and pliable filament
19:55inside would be stretched but if the light was off the cold brittle filament would break upon impact
20:07all these filaments are broken
20:12the outcome was that we found no vibe which was under electrical power during the impact of the aircraft
20:23investigators now have conclusive evidence of a sudden total power failure
20:31but what could have caused it
20:34the controller did tell us that another plane got struck by lightning
20:40maybe this one did too
20:43a lightning strike outside of the aircraft could lead to a problem with the electrical system inside of the aircraft
20:51if the electrical field of a lightning strike is very very high could be induced into the aircraft
21:01investigators search for evidence of lightning striking the fuselage of flight 108
21:10there must be a thousand pieces in here
21:14it's a painstaking process lightning could have struck anywhere lightning marks on the skin
21:21be looked like a circle you'll see the paint burned you may see some localized melting of the metal in
21:28that particular area
21:35over here
21:40what do you got
21:42i found it
21:45huh
21:45once you've found a piece of metal the lightning strike it's like okay where does it go on the airplane
21:50what's in the proximity of this is it next to the electronics is it next to hydraulics where is this
21:58lightning strike occurring
22:01the only way to determine where the mystery piece comes from is to reconstruct sections of the airplane
22:07okay
22:09no
22:11at the time of this accident uh reconstructions were fairly typical mainly didn't have as much data as we
22:18have now so reconstructing it made sense
22:30i think i've got it investigators match the piece of the plane to the left side of the fuselage
22:36forward of the wing this is where the lightning strike
22:42but could a lightning strike in front of the left wing actually cause a total electrical failure
22:49there are power system lines running right behind where the lightning struck
22:54can't be a coincidence
22:57is it possible that that lightning strike entered the electrical wires on the other side and therefore
23:04led to the loss of electrical power so that would have been the real focus of the investigation at this
23:09point
23:10so that's what's going to happen
23:16investigators examine what remains of flight 108's electrical wiring in search of evidence that the
23:23lightning strike jumped from the fuselage to the electrical system
23:29you would look for the insulation material the outsides and burned away is there melting inside the wires
23:37evidence evidence that somehow electrical energy got through the insulation barrier into the wiring
23:44and then was starting actually melting the wires locally how odd those signs of arcing
23:56we checked the wiring we checked the electronic components available from the wreckage for some
24:03indication for electrical overload
24:13finding lightning damage to the wiring not yet it's very possible once the lightning gets into the fuselage
24:20you may not see any direct impact in that area it flows into the aircraft and so even
24:29wiring is close by may appear to be unaffected but now this high energy has gotten into the airplane
24:36and the question is where does it go maybe i can find something in here
24:41after we found no evidence for damage in the wiring based on the lightning strike we had to do a
24:51deeper
24:51investigation within the systems and that means we had to look for damages in the avionic components
25:02the team now focuses on even smaller components of the electrical system
25:08the diodes let's check this out
25:15a diode is an electrical component that allows current to flow in one direction only preventing reverse
25:23current flow that could damage circuits or create malfunctions
25:30if the diode is working properly there should be resistance to high current flow
25:35current flow in one direction and not the other
25:42only 50 ohms almost nothing now the reverse
25:55also 50 ohms
25:58but investigators discover low resistance to current flow in both directions it's shorted
26:11the outcome of our investigation of the diets was that all diodes were open in both directions
26:18that means the diets were shorted the question now was why
26:24we decided to take these to a manufacturer and to ask them to do a deeper investigation
26:35results are in to better understand why the diodes shorted they examine test results provided by the
26:42manufacturer oh that's interesting looks like cracks in the center of the diode
26:55once you've seen that a diode has failed then you can do tests and research on a good diode to
27:01see
27:01how much energy you would take basically to fry that diode voltage tests are done to determine if
27:09the cracks in the diodes were the result of a lightning strike or something else a thousand volts
27:18investigators learn that when more than a thousand volts are applied to a working diode it will crack
27:24a lightning bolt can carry hundreds of millions of volts more than enough energy to crack the diode
27:30it must have been lightning the damage of the diodes only can be produced by high voltage
27:41could it be possible that high voltage would be produced within the aircraft and the answer was
27:49you know it could be only produced by the lightning strike
27:56basically the lightning hit the aircraft flowed through the system it impacted the diodes which fried
28:04them cracked them cracked them took them offline and that shut down the electrical systems on the aircraft
28:12the odds of lightning taking out an entire electrical system are next to impossible and yet that's what happened
28:23but this doesn't explain why the crew flew into the thunderstorm in the first place
28:31okay the primary rule is if you see a thunderstorm no matter what its size you avoid it you go
28:40around
28:40you divert you hold you do whatever you can you do not want to fly through a thunderstorm
28:53investigators examine nuremberg air services flight operations manual to understand why the pilots of
29:00flight 108 ended up in a thunderstorm i don't get it it clearly states flights in or near thunderstorm
29:07should be absolutely avoided so why didn't they do the sensible thing and go around the storm
29:14at that time they had several possibilities one possibility was just to prepare if they would fly
29:22through the thunderstorm what could happen what they have to do what they have to prepare another
29:27possibility could have been just to divert to another airport let's have a listen to what the pilots
29:34were saying about the storm check the radar thunderstorm could be rolling in after all halfway through the
29:47flight the crew learns there's adverse weather ahead maybe doesn't look particularly bad
29:58i'll check the adis the crew checks dusseldorf airport's weather service information bravo at 070 but
30:07there's no indication of a thunderstorm once they got the adis their expectation bias was that the weather
30:13was getting better broken clouds at 1500 feet nothing but a thunderstorm we should be fine
30:21the captain considers the information and makes his decision okay we'll continue with the approach
30:32they just assume best case scenario and don't do a proper briefing as professional pilots we always
30:38brief each other based off the worst conditions you never know if that 10 probability of thunderstorms
30:42actually happens and if it does happen and it's too late you don't have time to brief it
30:51and fd 108 11 minutes later the situation becomes more critical proceeding landing experienced a
30:59lightning strike about six miles final if i were the crew and i were on approach and uh
31:04pursuing trapping in front of me were to get struck by lighting at that point i would initiate a missed
31:08approach go around and hold somewhere and figure out what we're going to do because the weather at
31:12that point is moving on to the approach path you need to take that pretty seriously but that's not what
31:17the
31:17pilots do dusseldorf approach we copy and are looking outside nfd 108
31:28hey did you hear what happened to walter last weekend yeah not surprised hold on they should be
31:36talking about deviating or go around here not someone's weekend they should have been deciding
31:41where they were going to go and what they were going to do instead of going down this rabbit hole
31:44they
31:44just thought the other person's comfortable with it and will continue going if they're comfortable
31:47i'm comfortable investigators continue listening to the cvr as the pilots prepare for landing
32:10you're left of the center line what you're left of the center line you need to turn right
32:16the captain started deviating to the left apparently without telling the first officer of his plan i don't
32:21want to go in there i'm trying to get around it we're too close to the runway you can't change
32:25course now sounds like the captain is trying to deviate around the storm and the first officer
32:32isn't on the same page it's a bad idea to try and re-intercept the approach when you're already
32:37stabilized it's just a bad idea you just do it go around okay i hear you
32:53again no discussion of their options there's some tension in the cockpit there's some issue between
33:01the captain and the first officer we don't know exactly what it was but clearly this was not conducive
33:11to the crew working together to determine what was the best course of action so now
33:17the captain turns the plane directly into the thunderstorm
33:24hold on tight here it comes
33:33the crew knew what the other one was doing they hadn't briefed for the weather that they didn't
33:37have the plane set up for flying around in the vicinity of thunderstorms and they just kept going
33:49why wasn't this crew on the same page
33:56the understanding of the investigation team at that time was the communication between both pilots was
34:03not in a way as it should be
34:07what'd you find well investigators examine personnel records for insight into the pilots working relationship
34:19the captain had a total of two thousand four hundred and seventy three flight hours
34:25but only two hundred and seventy seven hours in the metro three that's not a lot of experience on type
34:33no it's not the fo
34:37the crew had basically the same number of flight hours but over thirteen hundred hours in the metro
34:50investigators discover that the first officer had much more experience on the metro liner than the
34:56captain
34:58with the crew having such an imbalance in the time the first officer is going to feel like
35:02they could be the captain that they got passed over for the upgrade they have more experience on the
35:06routes they have more experience on the plane more experience with the airline even in this case
35:12she probably didn't trust his handling of the aircraft that's never good in a cockpit
35:20did the pilots imbalance in experience make it difficult for them to cope with the lightning strike
35:31so they start making their descent here
35:35investigators examine how the pilots of flight 108 flew the plane as they entered the thunderstorm
35:41and then a minute before they lose power they start ascending again why would that happen
35:49let's hear what happens here
36:00okay glide alive
36:04quarter flaps
36:09selected
36:11three minutes from the airport the captain begins configuring the aircraft for landing and half laps
36:21half flaps please as they descend towards the runway the captain rushes his flap settings
36:30the plane is now climbing instead of descending
36:34the captain requested the next flap setting half flaps the airplane then ballooned up climbed an altitude 400
36:43feet i'm not sure that was so good the captain trims the plane's nose down to counteract the increase in
36:51altitude
36:52in response to the 400 foot climb the captain trims the airplane rather than just putting a few
36:58bits of electric trim in he holds the electric trim uh pitching the nose down quite substantially
37:03he then adds even more nose down trim
37:11we're still slightly high
37:19okay descending
37:24with all that trim the captain has added the plane is in a nose heavy position when the lightning strikes
37:41so now the captain loses the ability to recover
37:45when the lightning strike happens he loses electrical power so he may have a lot more heavier flight controls
37:52than he was prepared for and when the lightning strikes the instrument lighting fails making the instruments impossible to read
38:03there's no emergency procedure in the metroliner manual
38:06that tells you what to do if all your batteries fall offline
38:08you're a test pilot and at that point you use your pilot experience
38:12one of the things to do was for the non-flying pilot to get a flashlight
38:17to illuminate the standby instrument to help the flying pilot out the flashlights weren't found
38:23we don't know if they're on the aircraft or not the power failure cuts off their ability to see
38:29and to communicate with each other they couldn't hear each other we've lost electrical power
38:38we have nothing you've got a crew that can't communicate because you've lost the intercom system
38:43you've got a headset on and the metro is a very noisy cockpit so you can't hear the other person
38:47and
38:47what they're saying to you if they couldn't see their instruments or hear one another could the pilot
38:53still fly their plane they have aileron and rudder controls which aren't electrical the engines are
39:01still running the runway is about seven miles away they should have been able to use the controls they
39:09did have to land the plane they still had control over the ailerons over the rudder it was difficult
39:16but technically still flyable but without the ability to see their instruments they'd have no way of
39:21knowing where they were seconds later flight 108 is diving towards the ground
39:34the pilots had no chance to control the aircraft in a proper way because the light for the third
39:41artificial horizon was not there and they had no visual ground contact and i think under these
39:48circumstances it's nearly impossible to control the aircraft investigators finally understand how a
39:58lightning strike caused a fatal crash you're left of the center line what it starts with a poorly
40:13functioning crew you're left of the center line you need to turn right i don't want to go in there
40:18i'm trying to get around it we're too close to the runway you can't change course now okay i hear
40:24you
40:25instead of giving him the advice or the two crew mentality that we're not where we should be we
40:30shouldn't be here the first officer chose to go the other route which was shut down and only make
40:34the minimum calls which were deviation calls half flaps please
40:43the pilots decide to fly their nose heavy aircraft into a thunderstorm
40:52a powerful lightning strike we've lost electrical power causes a total power failure we have nothing
41:01and the disoriented crew where are we i can't tell loses control of the plane
41:26and the pilot's blind actions lasting more than a minute sends the plane into extreme turns and
41:39banks are we banking can't tell what's the airspeed don't worry about the speed just pull you think
41:45you can trust your senses but you can't you don't know if you're banking to the left you don't know
41:48if you're banking to the right you can't tell if you've got a nose low or nose high uh you
41:53can think
41:53you do you can think you trust it at the end of the day your gut instinct will be wrong
41:57the plane is so overloaded with the g-forces in these turns it broke up
42:06yeah
42:16pull up pull up i'm crying
42:20you're looking at a g-load that literally ripped the engine pylon off the wing that literally broke the
42:25wings bar the strongest part of the airplane broke it like a toothpick that way exceeded what the
42:30aircraft manufacturer ever designed that airplane to go through
42:49the main conclusion of the report by germany's air accident investigation unit is clear
42:55the crew flew into a thunderstorm even though they could have flown around it
43:02you have two fairly experienced pilots that they never ever should have been in that situation
43:07there were red flags throughout if anything can be learned from this one you got to speak up on
43:12a two-crew airplane you can't let the other person take you to the scene of the crash
43:16in their recommendations the fus reiterates the need for training and manuals that clearly describe how to
43:24operate in and near thunderstorms this is a very different crew than we see today who are well
43:32trained in cockpit resource management who work together as a crew and the systems change for the
43:38better and the airplanes are much better as for nuremberg air service the company soon replaced the
43:46remaining metrolinas in its fleet i made myself one of the last flight with the metroliner
43:52i had some tears in my eyes because i think it wasn't the aircraft's fault
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