BOTH engines GONE | British Airways CRASH in London

[Music] on january 17 2008 a mysterious failure caused a british airways boeing triple seven to come crashing down just short of london's heathrow airport this was the first full loss of a triple seven aircraft which had been operating without serious issue since 1995. in a strange twist the culprit in this accident seemed to vanish after the crash leaving investigators puzzled speculation was rife after the accident with some saying that a software glitch may have downed the aircraft or that there may have been radio interference from the prime minister's motorcade which was passing nearby at the time in the end investigators found that the cause was both far simpler and far more pernicious what follows is the curious story of british airways flight 38 the flight that showed how a collection of circumstances which in their own are harmless can combine to cause an accident this is also the story of how experience and quick thinking can be the difference between life and death at about 10 a.m local time on january 17th 2008 british airways flight 38 pushed back from the gate at beijing international airport in china on board were 136 passengers and 16 crew the flight was bound for london's heathrow airport in england a 12 hour 8 000 kilometer journey in the cockpit on this flight were three experienced pilots captain peter burkel was 43 years old and had 12 700 hours of flying experience under his belt over 8 000 of which were on the triple seven he doesn't know it yet but in 12 hours he will draw upon this experience to save his own life and the lives of everybody else on board the plane in the right-hand seat was the senior first officer john coward he was 41 years old and had 9 000 total flying hours 7 000 of which were on the triple seven the other pilot first officer conor mcgenis was 35 years old and had five thousand hours of fight experience just over 1000 of which were on the triple seven the presence of three pilots on this flight meant that each of them could take a three-hour break at some point during the cruise ensuring that they would all be well arrested for the approach into london the aircraft being used for this flight was 7 years old and had entered service with british airways in 2001. the triple 7 was and still is a highly modern aircraft with an excellent safety record up until this flight not a single triple 7 had been lost in the aircraft's 13 years of service flight 38 lifted off the runway at beijing at nine minutes past 10 local time and headed northwest towards london it was carrying 79 000 kilograms of fuel for the long journey the aircraft's flight plan required it to climb initially to 10 400 meters or about 34 000 feet before descending back down to 31 500 feet because of the extremely cold air at that altitude the air at altitudes used by commercial aircraft is normally very cold typical temperatures lie between about -40 and minus 57 degrees centigrade on this day however conditions were unusually cold with temperatures as low as -76 degrees centigrade or minus 105 degrees fahrenheit nonetheless air traffic control asked the crew if they could climb to about 35 000 feet the crew accommodated this request and monitored their fuel temperature closely they knew that they had to ensure that the fuel did not come within three degrees of its freezing point which was minus 47 degrees centigrade even though the outside air was much colder than minus -47 degrees the temperature experienced by the surface of the plane and thus the fuel was much higher this is because the friction of the fast-moving air heats the surface of the plane raising its temperature substantially at the speed's commercial aircraft travel at this friction increases the temperature experienced by the plane by about 30 degrees centigrade as flight 38 continued across siberia it eventually burned off most of its 79 tons of fuel making it light enough to climb to 40 000 feet the pilot selected the vertical speed mode of the autopilot and set it to climb at four hundred feet per minute until it reached forty thousand feet it stayed at this altitude until approaching the coast of england from the north sea two minutes past noon local time the pilots began their descent towards london they first leveled off at 11 000 feet and entered the holding pattern to the northeast of london they spent five minutes in this holding pattern and continued descending to 9000 feet during this time they then received radar vectors from air traffic control to line up with runway 27 left at heathrow a few minutes later the pilots were lined up with the runway on final approach they had the aircraft fully configured for landing at 1200 feet with the gear down and the flaps extended to 30 degrees the autopilot was flying the aircraft at this point and the auto throttles were controlling the engines in a few seconds things would start to go seriously wrong the auto thornton made some minor adjustments to the engine thrust increasing and then decreasing it again to maintain the aircraft's final approach speed of 135 knots however during one of these increases in thrust the right engine did not respond rather than increasing its thrust in response to the auto throttle command its thrust actually decreased seven seconds later the left engine experienced the same problem the aircraft was merely 600 feet above the ground at this point and less than a minute from touchdown at this point air traffic control then cleared the aircraft to land that three eight with line two seven left to win two one zero ten knots good land two seven left three the first officer who's the pilot flying noticed that the thrust levers were uneven with the left lever leading the right several seconds later the auto throttles moved the thrust levers to the full forward position as they realized that the engines were not producing the commanded thrust when the aircraft was 430 feet above the ground the captain made the standard call out of stable indicating that the approach could be continued however the co-pilot replied just seven seconds after this the co-pilot said what's happened to the speed yeah but look what's going on he pointed to the thrust levers which were commanding full thrust and yet the engines were barely at idle power he pulled the thrust levers back and then pushed them forward again but nothing happened the relief pointed sitting in the jump seat behind the pilots said that it looked as if both engines had failed however this wasn't the case and so the pilots couldn't perform the double engine failure drill the aircraft was now over a mile from the runway and it was losing speed and altitude if the pilots couldn't get the engines to produce more power they could crash into a housing estate just short of the runway the captain quickly scanned the cockpit looking for anything that was out of place like a fuel pump that was turned off or whether the speed brake was extended but everything was normal the autopilot tried to pitch the aircraft up in order to maintain its glide path towards the runway but this decreased the speed further and risked causing the aircraft to stall and fall out of the sky at about 240 feet above the ground the airspeed had decayed to just 115 knots which was well below the target approach speed the aircraft was now falling rapidly towards the ground with a descent rate of 1800 feet per minute more than double the usual rate the crew had to act fast to salvage the aircraft the captain drew in his experience to make a number of bets that he thought might reduce the number of casualties first he let the first officer continue flying the aircraft as he was highly experienced and this would give the captain himself time to find other ways to save the aircraft he knew he had to reduce the amount of drag on the aircraft in order to extend its gliding distance so he could crash within the airport perimeter he kept the landing gear extended as even though these increased drag significantly he knew they would absorb the brunt of the impact forces however he reduced the flaps from their current setting of 30 degrees to 25 degrees the hope here was that this small reduction in drag would enable the aircraft to fly far enough to avoid hitting the building short of the runway this had an immediate effect the aircraft's rate of descent went from 1800 feet per minute to 1400 feet per minute and it then became obvious to the crew that they would clear the buildings and that they would probably crash down within the airport perimeter the captain would later say that in this moment his estimation of the death rate among passengers went from 100 of passengers to about 50 percent the speed of the aircraft was now 108 knots and the stick shaker activated indicating that it was close to stalling the first officer pushed the nose down slightly to stop the speed decaying too much there were now 10 seconds until impact and the captain realized that the last thing he could do to improve the survivability of the accident was to make a made a call to air traffic control mayday you made a speed bird speed bird nine five nine five the aircraft impacted the ground hard about 330 meters short of the runway threshold it bounced into the air and then hit the ground again this time sliding uncontrollably along the ground it came to rest a few seconds later just 372 meters from the first impact point here's the air traffic control audio from immediately after the crash the position is the threshold runway two seven left aircraft type is a triple seven natural problem is crash aircraft has crashed is south zero one to go around all right i can't confirm incredibly all 152 passengers and crew survived the crash there was just one serious injury one passenger's leg was broken when part of the landing gear breached the fuselage during the crash sequence investigators got to work immediately after the accident in the absence of any obvious cause for this sudden loss of engine thrust the media went on a speculation frenzy how could an accident like this happen to british airways one of the safest airlines in the world and to the boeing triple 7 one of the safest aircraft in the world indeed this was the first time a triple seven had been written off due to a crash since its introduction 13 years earlier in 1995. with hundreds of these aircraft and passenger servers around the world should this incident be caused for concern initially everything was on the table as a possible cause there was speculation that the highly automated systems on the triple 7 had malfunctioned due to a software glitch there was even discussion around the idea that the prime minister's motorcade which was passing nearby at the time had interfered with the aircraft systems and caused the loss of power however when investigators turned their attention not on the flight's final few minutes but on the hours leading up to the crash they discovered something unusual on first appearances the fight had been completely normal up until the final few seconds when both the engines failed to produce the required thrust however after looking a bit closer investigators discovered that there were a few ways in which this fight was a statistical outlier investigators examined data from 178 000 fights by boeing triple sevens and found that this flight was unique in that it had a combination of a low fuel flow to the engines during the cruise phase of the flight and a high fuel flow during approach while the fuel temperature was low the majority of flights had a higher flow of fuel to the engines during the cruise and a higher fuel temperature on final approach the reason this flight had a low fuel flow during the cruise is that when the pilots made a number of step climbs up to higher altitudes throughout the flight as the plane got lighter they did this using the vertical speed mode of the autopilot and commanded a slow rate of climb of just 400 feet per minute this slow rate of climb meant that the engines did not need to significantly increase their fuel flow in order to accomplish the climb this meant that naturally occurring ice crystals in the fuel had been able to accumulate in the fuel pipes without being dislodged normally the commanded rate of climb would be higher or pilots would use the v-nav mode of the autopilot to accomplish the climb which would typically command a higher thrust setting then on final approach the fuel temperature on flight 38 was minus 22 degrees centigrade which is unusually low for this phase of flight this was because the aircraft had been flying in unusually cold air for the previous 11 hours and the fuel temperature remained well below freezing throughout the flight this meant that any ice which had been accumulating in the fuel lines during the flight remained there even during the approach when the fuel would typically be warmer this ice occurs naturally in fuel and so it should not have been a problem for the fuel system however the fuel temperatures during much of the fight were in the so-called sticky range where ice crystals are most likely to adhere to their surroundings during the initial descent the engines were on low power meaning that the fuel flow was low and this ice remains stuck to the fuel pipes however when the plane was on final approach and there were engine accelerations this increase in fuel flow dislodged the ice causing it to flow through the fuel system and form a restriction on the face of the fuel oil heat exchanger pictured here this blockage was enough to significantly reduce the fuel flow to the engines causing the reduction in thrust here's a picture from the final report into this accident which shows just how unusual this particular set of circumstances were on british airways flight 38. each of these dots is a flight conducted by british airways triple 7. the vertical axis shows the amount of fuel delivered by each main tank which is below 20 degrees centigrade and with a maximum fuel flow of 10 000 pounds per hour in other words flight 38 which is the outlier at the top of this graph consumed about 25 000 kilograms of fuel from each tank at minus 20 degrees and at a maximum rate of 10 000 pounds per hour the takeaway from this chart is that it is highly unusual for a triple 7 to consume this much cold fuel at this lower rate of fuel consumption in these very specific and unusual conditions ice may build up in the fuel lines and when engine thrust is increased closer to landing it may be dislodged where it travels through the fuel lines and causes an obstruction at the fuel oil heat exchange the certification requirements for the engines and the fuel system did not require them to be invulnerable to this phenomenon as it was simply not known about at the time as a result of this accident rolls-royce the manufacturer of the engines changed the design of the fuel oil heat exchanger so that it was less vulnerable to ice buildup under these conditions boeing also recommended that if pilots suspect a fuel icing problem they should bring the thrust back to idle for 30 seconds then increase the thrust to clear the blockage this could not have been done on british airways flight 38 however given how close it was to the ground when the loss of thrust occurred in the end it was miraculous that this fight ended as well as it did and near total loss of engine thrust on short finals is a life-threatening situation and the quick thinking actions of the flight crew saved many lives on board after the crash boeing test pilots spent months recreating the landing in a full motion boeing triple seven simulator and were unable to achieve a further glide than was achieved by the pilots on this day since these changes to the design of the fuel oil heat exchanger there has not been another similar accident on the boeing triple 7 and it remains to this day one of the safest passenger aircraft in the sky special thanks to the members of this channel for helping make this video possible i'd especially like to thank users euk95 andrew scheiskolov and antelope pony for their extremely generous contributions if you'd like to support the channel and get perks like early access to videos or voting on future episodes please click the join button i've also started a patreon which is linked here thanks again for watching you

Channel: Green Dot Aviation

Views: 450,963

Keywords:

Id: JUkaOTO0uVk

Length: 15min 17sec (917 seconds)

Published: Tue Feb 08 2022