Fire on the Runway: The Manchester Airport Disaster and the tragedy of British Airtours flight 28M
On the 22nd of August 1985, a Boeing 737 packed with holiday travelers suffered a catastrophic engine failure as it sped down the runway in Manchester, England, prompting the pilots to reject the takeoff. But by the time the plane pulled safely off the runway and rolled to a stop, a massive curtain of flame was already engulfing the rear fuselage, pouring forth from a ruptured fuel tank to assault the passenger cabin with unprecedented ferocity. As smoke and fire burst into the airplane, the passengers made a mad rush for the exits, only to find themselves tangled together, fighting through packed crowds while enveloped in toxic fumes. Dozens perished amid the panic, collapsing in their seats, in the exits, and in the aisle, even as firefighters struggled to pull unconscious victims from the burning plane. By the time it was over, 55 people were dead aboard a plane that never even got off the ground.
Unfortunately, this was far from the first time that large numbers of people had lost their lives due to smoke and fire in an otherwise survivable accident. In a comprehensive final report, British investigators made clear that this kind of tragedy was unacceptable. Even though the causes of the engine failure were elucidated in great detail, the failure itself should never have been a fatal event, and investigators ultimately proposed a wide range of innovative solutions designed to extend the available survival time in a catastrophic aircraft fire. But the virtual elimination of such accidents in recent years may have little to do with any of the most well-known proposals — some of which were rejected, while others are popularly believed to have been implemented, but were not — and rather more to do with certain findings that received far less attention.
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In 1969, the UK state-owned airline British European Airways launched a wholly owned subsidiary called BEA Airtours, specializing in charter flights to holiday destinations arranged on behalf of large tour operators. The airline subsequently became part of British Airways when BEA was merged with the British Overseas Airways Corporation to create the unified flag carrier in 1974, at which time BEA Airtours was renamed British Airtours (although, as a fun piece of trivia, it retained the callsign “Beatours”). Under British Airways, the airline continued to operate holiday flights for tour operators until BA exited the inclusive tour market in 1995, at which time the company was sold and eventually merged into Thomas Cook.
In 1980, British Airtours replaced its aging fleet of Boeing 707s with nine short- to medium-range Boeing 737–200s, five long-range Lockheed L-1011 Tristars, and a Boeing 747. The 737s, part of the earliest mass-produced generation of the popular model, were powered by then-ubiquitous Pratt & Whitney JT8D engines, which were also used on the Douglas DC-9, Boeing 727, and several other aircraft types. The JT8D was at that time the most widely used turbofan engine globally, and it was generally quite reliable, but as with any engine in such widespread operation — and especially one developed in the 1960s — it encountered its fair share of problems over the years.
One recurring issue that would later become a centerpiece of the Manchester tragedy involved cracking in a set of components called the combustor cans.
Inside a jet engine, pressurized air is mixed with fuel and ignited in the combustion chamber in order to spin a turbine. On the JT8D, the actual combustion occurred inside a set of nine “combustor cans” arranged circumferentially within the combustion chamber. Within each can, fuel and air were mixed in the appropriate ratio, ignited, and propelled rearward through the turbines.
The cans themselves were constructed from two main components, consisting of a metal dome at the front, followed by a set of 11 “liners,” made of Hastelloy X sheet material, which were welded together to form the body of the can, as shown below. Each tube-shaped liner slightly overlapped with the next so as to provide a contact surface for welding, lending the cans some passing resemblance to a pine cone, or maybe Taipei 101.
An interesting, and highly relevant, feature of the combustor cans was that the combustion temperature achieved inside them was greater than the melting point of the material from which they were made. The integrity of the cans was thus dependent on the presence of cooling airflow provided by all the pressurized air that was not being directed through the cans. Only a small percentage of the air propelled into the combustion chamber by the compressors is actually used for combustion; the rest simply moves around the combustor cans within a containment vessel called the combustion chamber outer case, or CCOC. The effect of this relatively cool, fast-moving air prevented the combustor cans from reaching dangerous temperatures.
However, neither the airflow nor the combustion occurred perfectly evenly, and minor imperfections tended to generate hot spots in the cans where the strength of the material was greatly reduced. Under the loads associated with normal operation, these areas tended to crack within a relatively short period of time. However, crack growth slowed substantially as soon as the cracks tried to expand into cooler areas where the material was stronger, so this condition was not an immediate cause for concern. Instead, Pratt & Whitney supported various methods for repairing cracks in the combustor cans in order to reset their service lives. Airlines invariably chose to do this at scheduled overhauls when the engines would be removed from the wings for comprehensive servicing.
The JT8D engine did not have a particular manufacturer-recommended interval between overhauls, so British Airtours reached an agreement with the UK Civil Aviation Authority (CAA) to conduct a “light” maintenance teardown, including combustion section overhaul, after 10,000 operating hours, followed by a heavier teardown and overhaul at 16,000 hours with hopes for an extension to 20,000. Therefore, it could be expected that the combustion chamber would be disassembled and the combustor cans inspected for cracks on an interval not greater than every 10,000 hours.
In the winter of 1983/1984, an engine was removed prematurely from a British Airtours 737 following reports of damage. During this teardown, it was decided to conduct an early inspection of the combustor cans, which had accumulated 7,582 hours since new. Various cracks were detected in the cans during radiographic and visual inspections (shown above), all of which were repaired via direct fusion welding.
Among these cracks were several on combustor can №9 that had developed circumferentially along the joint between liners 3 and 4, one of which had reached a length of 160 millimeters (6.3 in). This was probably one of the longest cracks in a JT8D combustor can ever encountered by British Airways, but it did not appear to have been given any special attention, nor was replacement of the can considered. In fact, Pratt & Whitney’s procedures for repairing combustor can cracks included limits on crack width and level of oxidation, but no maximum repairable crack length.
By fusion welding cracks in the combustor cans, British Airways (which handled maintenance for its subsidiary) believed that it was restoring the fatigue life of the can to its original, “as new” value. In this case the fatigue life refers to the expected number of hours or cycles of operation before the can fails, with the usual failure mode being a 360-degree circumferential crack that splits the can into two pieces. British Airways’ maintenance regime assumed that a weld-repaired can would have the same fatigue life as a new can, such that once repairs were effected, the 10,000-hour time to next inspection would be reset without any modification. But Pratt & Whitney was actually well aware that this assumption was false, and had even attempted to warn operators that the fatigue life of a weld-repaired can was not necessarily as long as that of a new can. This was because only those cracks identified by inspectors were being weld-repaired, while embryonic cracks could escape detection and then continue growing as soon as the can was put back into service, shortening its lifespan.
Apparently unaware of this, in February 1984 British Airtours took the repaired combustor can with the 160 mm welded crack and reinstalled it on a different engine that was fitted in the №1 (left) position on G-BGJL, the Boeing 737 later involved in the accident. In service, additional tiny unrepaired cracks in the joint between liners 3 and 4 resumed their growth, linking up and expanding around the circumference of the can, despite the prior attempts to repair it. As these unified cracks became longer, the power output of the can began to drop, which reduced the engine’s ability to spin the turbine. This manifested intermittently in the form of a lower than expected turbine rotation speed for any given cockpit thrust lever position. This also resulted in slower than normal acceleration on takeoff, because the engine had to spin up from a lower idle RPM. In other cases, the thrust levers had to be staggered, with the left thrust lever positioned farther forward than the right lever to achieve the same thrust output.
In total, between February 1984 and August 1985, pilots who flew G-BGJL logged two reports of throttle stagger, 11 reports of slow acceleration, four reports of both of those symptoms together, and two reports of slow engine startup. British Airways maintenance personnel tried a variety of minor fixes, but a combustor can issue was not listed in the troubleshooting manual as a possible cause of slow acceleration or thrust lever stagger. On most occasions, mechanics simply checked the bleed air system for leaks that might be siphoning air from the engine, and emptied the bleed air water filters. Because the problems were intermittent, recurring a couple times a month or less, these actions usually appeared to be effective and no deeper examinations were conducted.
On August 20th, 1985, a flight crew again reported slow acceleration and throttle stagger, and mechanics checked again for leaks and bled the fuel system. This time, however, the problem came back the following day, when another crew reported slow acceleration, throttle stagger, and low ground idle RPM. In response, mechanics adjusted the ground idle trim screw, which changes how much fuel is fed to the engine when the thrust levers are positioned at ground idle. Adjusting the screw until the ground idle RPM matched that of the right engine solved the low ground idle speed, but didn’t seem to fully address the other reported issues. In the technical log, mechanics wrote, “Ground idle adjusted 1 turn increase. Now matches №2 engine but still seems slow…. Would crews please report further.”
Unknown to anyone at the time was that the problem with the №9 combustor can on the №1 (left) engine was about to become much more serious. Sometime in the days leading up to August 22nd, the circumferential cracks in the joint between liners 3 and 4 finally fractured around the whole 360 degrees of the can, separating the dome portion and the first three liners from the aft portion containing the other 8 liners. The engine continued to operate in this condition for at least a few flights, during which time the partially loosened dome jiggled about in its mountings, progressively wearing them down, until it was finally able to cant up to 11 degrees outboard from its nominal position. This allowed combustion products from inside the can to be redirected against the sidewall of the combustion chamber outer case, or CCOC, which was not designed to withstand such intense heat. This torching effect rapidly reduced the thickness of the CCOC wall to effectively zero across an area measuring 175 centimeters in length.
Because it must contain highly pressurized air being forced aft by the compressor section, the cylinder-shaped CCOC is essentially a pressure vessel, much like the fuselage of an airplane. If the case is sufficiently weakened, it will be unable to withstand this high internal pressure and will violently explode. As such, a rapid countdown to disaster had now begun.
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Early on the morning of August 22nd, 131 passengers and 6 crew boarded G-BGJL for British Airtours flight 28M from Manchester, England, to the popular Greek island of Corfu. The flight was fully booked with all but two seats filled, which was typical of inclusive tour flights.
In command were 39-year-old Captain Peter Terrington and 52-year-old First Officer Brian Love, who had about 8,400 and 12,200 hours, respectively. They were supported by four cabin crew, consisting of 39-year-old Purser Arthur Bradbury, and Stewardesses Joanna Toff (26), Sharon Ford (23), and Jacqui Urbanski (27). Bradbury and Toff occupied seats in the forward galley, while Ford and Urbanski were positioned at the rear.
Before departure, pilots Terrington and Love reviewed the technical log and noted the maintenance crew’s request that they “report further.” First Officer Love happened to have been the very pilot who made the log entry about slow acceleration on the 21st, and he was able to describe the events to Terrington in some detail. Both pilots agreed that they would monitor the engine’s performance during start, taxi, and runup, and as part of the pre-flight briefing they also discussed their plans in case of a rejected takeoff.
At 6:12 a.m., flight 28M was cleared for takeoff on Manchester’s runway 24, with a reported light headwind blowing out of 250˚ at 7 knots. As pilot flying, First Officer Love called for takeoff power, and Captain Terrington observed that the left engine accelerated normally, seemingly confirming that the previous day’s problem had been fixed. Confident that the plane was in good working order, they sped away down the runway, swiftly reaching 80, then 100 knots.
Suddenly, at a speed of 126 knots, the passengers and crew heard what sounded like a muffled thud from the left side of the airplane. Unsure what had caused the noise, but suspecting a burst tire or bird strike, Captain Terrington immediately called out, “Stop,” and First Officer Love initiated the rejected takeoff procedure, applying the brakes and engaging the thrust reversers.
In fact, what had occurred was far more serious than Terrington could have predicted. Fatally compromised by its exposure to hot combustion gases, the CCOC in the left engine explosively burst as power was increased, shattering the surrounding fan case and ejecting the combustion chamber contents upward and outward at considerable speed. Ripped from its mountings, the detached dome of combustor can №9 was hurled clear out of the engine and into the underside of the left wing, where it impacted a fuel tank access hatch with appreciable force. The hatch shattered under the heavy impact, breaching the tank, which was fully loaded with fuel for the journey to Corfu; within moments, kerosene was pouring through the breach at an astonishing rate. It took at most a few seconds for that stream of fuel to come into contact with hot engine components, at which point it ignited into a tremendous plume of fire.
As the fire erupted from behind the left wing, the pilots initially remained unaware. Still believing that a tire failure might have occurred, Captain Terrington advised First Officer Love not to hammer the brakes in case the landing gear had been damaged. But just moments later, and only nine seconds after the explosion, Terrington was just beginning to report the rejected takeoff to air traffic control when an alarm sounded, warning of a fire in engine №1. The fire was actually outside the engine, but had already grown so large as to trip the engine’s internal fire detection circuit. Terrington added to his transmission, “it looks like we’ve got a fire on number 1,” the continuous sound of the fire bell audible in the background.
Observing the plane decelerating on the runway with an immense cloud of smoke and curling flames trailing behind it, the controller replied, “Right, there’s a lot of fire, they’re on their way now.” In the fire station, the crash alarm sounded, but the firefighters were already out the door, having been alerted to the emergency by the sound of the explosion itself.
On board, with the speed reducing to 50 knots, Captain Terrington asked air traffic control whether they should evacuate, as he was still unable to see the scale of the fire behind him. “I would do via the starboard side,” the controller replied.
Instead of stopping on the runway, Love slowed down just enough for Terrington to pull off the right side of the runway and into an exit called Link Delta. This was consistent with his original belief that they had suffered a burst tire or bird strike, and although in theory an engine fire required an immediate stop on the runway, they had very little time to recognize the need for a change of plans.
Thirty-nine seconds after the explosion and decelerating through 20 knots, Terrington used his tiller to steer the plane into Link Delta, pursued by a towering wall of smoke and flame erupting from the trail of spilled fuel. The scale of the fire was immediately apparent to most of the passengers, particularly those in the rear of the cabin on the left side, who were seated so close to the flames that many began to rise from their seats while the plane was still moving. Other passengers shouted at them to sit down, and Purser Arthur Bradbury also urged that they remain seated, being unable to see the fire from his position due to the forward galley bulkhead.
Over the public address system, Captain Terrington announced, “Evacuate on the starboard side.” Bradbury opened the cockpit door to seek confirmation of the order, but at the back of the plane, the need for the evacuation was plainly evident. One of the aft stewardesses, presumably Urbanski, responded to Terrington’s order by opening the right rear exit door (R2) and deploying the slide while the plane was still in motion.
Seconds later, the aircraft came to a stop in Link Delta, approximately perpendicular to the runway. The pilots pulled out the passenger evacuation checklist, which was designed to ensure the plane was safe before exiting, but quickly discovered that it was inapplicable to their situation — the checklist was 15 items long, and evacuating the passengers was item #14, all the way at the bottom.
Simultaneously, Purser Bradbury attempted to the initiate the evacuation by opening the right forward door (R1), but as he did so, the lid of the slide pack came open prematurely and snagged on the doorframe, preventing it from rotating more than a few degrees out of the closed position. Thinking quickly, he abandoned the R1 door and crossed to the L1 door, opposite R1 on the left side of the aircraft, and threw that open instead.
By that time, conditions in the back of the airplane were already deteriorating. As fuel continued to pour through the breach in the left wing tank, it pooled near the aft left cabin, where the 7-knot wind out of the west pushed the flames directly against the fuselage. Within seconds, the intense blaze penetrated the outer layer of fuselage skin, and smoke began to pour into the rear cabin through every crack and crevice, including the wide open R2 door. This smoke was thick, black, and choking, almost tar-like in its consistency, and chock full of eye-watering combustion byproducts. Its arrival induced immediate panic in the back of the aircraft, compelling people to surge forward via any available avenue, whether that meant shoving their way up the aisle or clambering directly over the backs of the seats.
In the front of the cabin, passengers queuing for the forward exits were delayed by the difficulty opening the R1 door, resulting in a logjam as people moving up the aisle and over the seats reached a bottleneck at the galley bulkhead. The passageway through the bulkhead was only 57 centimeters (22.5 in) wide, too narrow for two people to pass abreast, and the sudden crush of passengers had wedged several people quite tightly inside it. Amid frantic screams and cries, stewardess Joanna Toff reached into the mass of people and pulled free a young boy, after which the logjam broke, sending passengers pouring through the now open L1 door. Approximately simultaneously, the first fire trucks arrived on the scene, one of which began attacking the fire around the left engine.
Farther back, observing the growing queue ahead and the rapidly approaching smoke behind, passengers began urging those seated in row 10 to open the right overwing emergency exit. In 1985, cabin crew were not required to brief exit row passengers on how to operate the exits, as they are today, and this had not been done. Unsure what to do, the passenger in seat 10F attempted to open the door but failed. Her traveling companion in seat 10E reached over and managed to pull the door open handle, but as soon as she did so, the 22-kilogram (48 lb) door toppled inward on top of passenger 10F, pinning her in her seat. Only with the intervention of additional passengers was the door removed from row 10 and tossed over the seatbacks into row 11.
As dozens of passengers from the back of the aircraft fought to reach the right overwing exit, stewardess Jacqui Urbanski tried to direct passengers aft to the R2 door, but the smoke in this area was very dense and the situation probably reached the point of no return within seconds. Witnesses recalled briefly spotting Urbanski in the R2 doorway before she was obscured by smoke, after which she was not seen again. No one escaped through this exit, as passengers fled forward instead. Amid this mad, panicked rush, people collapsed in the aisles, scrambled over seatbacks, and pressed into a great heaving crowd that collectively attempted to force itself through an overwing exit measuring only 97 by 51 cm (38 by 20 in). One survivor from the front of the cabin who looked aft during the evacuation said he saw a great mass of people jammed together in the center section, “howling and screaming” in terror.
Up front, as passengers streamed out the L1 door, Purser Bradbury returned to the R1 door and managed to force it open, creating a second exit path. But because the aisle and galley bulkhead were only wide enough for passengers to pass single file, the sudden availability of another exit at the front didn’t accelerate the flow of people at all.
Then, almost as soon as the R1 door was opened, a wall of black smoke rolled rapidly from one end of the cabin to the other, hugging the ceiling, until it reached the galley bulkhead, curled downward, and reversed upon itself, sweeping back the way it came. The toxic cloud completely enveloped both exit queues within seconds, plunging dozens of passengers into a choking, caustic darkness. “Within one or two breaths of the dense atmosphere,” investigators would later write, “survivors recall[ed] burning acidic attack on their throats, immediate and severe breathing problems, weakness in their knees, debilitation, and in some instances, collapse. A male passenger from seat 15C recalled taking one breath which immediately produced ‘tremendous pain’ in his lungs and a feeling that they had ‘solidified.’” A single breath was enough for many passengers to become certain that they would die if they took another.
At the front of the plane, the queue cleared as the last passengers, feeling their way along the walls with their eyes jammed shut, finally staggered out the door. Despite the thick smoke, stewardess Toff could see additional passengers collapsed in the aisle, and together with Bradbury, she pulled several of them to safety. By that point Bradbury feared that if he took even one more breath of the toxic atmosphere, he would not survive, and he was forced to make a hasty exit. Spotting her in the doorway, a firefighter told Toff to jump too, and after just a moment’s hesitation, she also abandoned ship. Farther forward, the pilots came to a similar conclusion, choosing to cut short the still incomplete evacuation checklist when they spotted fire and smoke creeping closer to the cockpit. Both bailed from the airplane via the starboard cockpit window, dropping to the ground using the built-in escape rope.
At the right overwing exit, the last moments of the evacuation were hellacious beyond all imagination, according to those few who lived to describe them. Amid the smoke, it was impossible to scream. People fell atop one another like dominoes, collapsing inside the exit, half inside and half outside the aircraft. One survivor recalled looking behind him to see huge tongues of fire erupting from floor to ceiling, illuminating the forms of people, still sitting in their seats, engulfed in flames. Several passengers who collapsed in the exit managed to recover enough to haul themselves out, but within a short time the conditions became completely untenable, and no one else emerged from the blackness. Dozens perished there, just meters from salvation, locked together in their final moments as the last shreds of hope slipped away.
Outside the airplane, firefighters had managed to extinguish the fire on the left wing and had made good progress against the pooled fuel fire beneath the aft cabin, but by then the seat of the fire had migrated inside the airplane, where their hoses couldn’t reach. In 1985 it was the case, and in many places it still is the case, that the only way to fight a fire inside the aircraft is to have firefighters enter the cabin with breathing apparatuses and attack the fire with hand lines, which the Manchester Airport fire crews were poorly equipped to do. But even without entering the cabin, they managed to save a life. Around 5 and a half minutes after the plane came to a stop, and well after the last passengers had exited under their own power, firefighters spotted a hand waving in the overwing exit. Trapped underneath the body of a man who had collapsed and died partly within the exit, they found a boy of 12 or 13, somehow still alive long after those around him had perished. Firefighters rushed him to a waiting ambulance, and a more focused rescue mission was launched through the R1 door in an attempt to reach passengers who may have collapsed in the forward cabin. But before anyone could be found, an explosion inside the cabin blasted a firefighter out through the R1 door and down to the ground, inflicting injuries. And to make matters worse, water supplies were starting to run low, making it difficult to sustain a prolonged operation inside the aircraft. Fearful for the safety of his men, the officer in charge called off the rescue mission in order to wait for a steady water supply to be established.
In search of more water, the crew of one truck tried several hydrants on the airport grounds, only to find that the lines had been improperly shut off by a contractor that was carrying out upgrades on the hydrant system. Fortunately, within a short time, vehicles and personnel from the Greater Manchester area arrived at the scene, at which point a concerted interior attack was finally carried out, beginning around 30 minutes after the start of the incident. Equipped with breathing apparatuses, the Greater Manchester Division Officer and another firefighter entered the cabin. Although they encountered severe conditions with restricted visibility, they managed to locate two bodies, radioing in the first report advising of fatalities. But just three minutes later, in an incredible stroke of luck, they found a man unconscious in the aisle with vital signs still present, having somehow survived the toxic cabin atmosphere for more than half an hour.
Although this survivor was rushed to hospital in critical condition, the smoke had unfortunately damaged his lungs so extensively that he later contracted pneumonia and died six days after the accident.
Only after the fire was fully extinguished did a more comprehensive search reveal the true scale of the tragedy. In total, 54 people were found dead inside the aircraft, for a total death toll of 55 out of the 137 on board. Among the dead were the two aft stewardesses, Urbanski and Ford, who perished at their stations alongside numerous passengers. Most of those who died were seated in the rear. In the last six rows, from 16 to 22, only five out of 34 passengers escaped alive. The rearmost of these was seated in row 20, and was the only survivor from this row; he was able to recall seeing stewardess Sharon Ford “trapped in a melee of passengers” near the unopened L2 door, but little else about her fate was known, as none of these passengers survived.
Surveys would later reveal that of the 78 passengers who survived the fire, 17 escaped through the L1 door, 34 through the R1 door, and 27 through the right overwing exit. The R2 door was opened but was not used, as the smoke in this area was too thick; the left overwing exit and the L2 door were never opened due to their close proximity to the fire. That left only three out of six exits, two of which were at the very front of the aircraft. The right overwing exit ended up being the closest exit to 100 out of the 131 passengers, and 76 of them would have had to pass by this exit to reach any other. Furthermore, only 23 people escaped before being enveloped by smoke, leaving the remainder to fight toward this bottlenecked exit amid toxic darkness. Many people in this queue never stood a chance, and witness accounts painted a harrowing picture of their final moments. But why had it come to this in the first place? How could a seemingly normal rejected takeoff, with an almost entirely undamaged airplane, have descended so quickly into a fatal nightmare? These questions would be foremost in the minds of the investigators as they launched what would become one of the most extensive air crash investigations in British history.
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It was apparent to the Air Accidents Investigation Branch (AAIB) from an early stage that the №1 engine’s combustion chamber outer case had ruptured and launched the dome portion of combustor can №9 into a fuel tank access panel, creating a fuel leak that caused the fire. In fact, it was possible to look straight through into the combustion chamber from the outside, where the crumpled remains of the rest of can №9 were clearly visible. It was further established that a crack had completely circled this combustor can at the joint of liners 3 and 4, leading to displacement of the dome, impingement of combustion gases against the wall of the CCOC, and subsequent explosive failure thereof.
This exact failure scenario was actually well known to Pratt & Whitney. The manufacturer had been made aware of 12 reported cases of explosive rupture of the CCOC on JT8D engines, three of which were traced back to failures of combustor cans, and in two of these cases parts of combustor cans were thrown from the engine, resulting in minor airframe damage. Combustor can failures had also caused four reported cases of non-explosive burn-through of the CCOC. This number of incidents was not especially high for an engine model in such widespread use, but the pattern was significant enough for Pratt & Whitney to send a letter to all JT8D operators in 1980 describing the problem and proposing a number of corrective actions employing existing procedures. Pratt & Whitney followed up later that year with another letter recommending regular inspections for cracks in the liner joints, replacement of extensively repaired individual liners, and full removal of cracks prior to weld repairs. The letter also warned that repaired liners have a lower fatigue life than non-repaired liners. Later, in February 1985, Pratt & Whitney issued another telex to JT8D operators describing the same issue, while also advising that slow starting and acceleration could be a sign of combustion chamber damage. Similar information was also presented at JT8D Operators Conferences in 1980 and 1985.
Unfortunately, British Airways had not followed any of the advice contained in these communications. The airline’s engineering department had received all the letters and telexes, but believed the reported problems to be isolated to “high-time” and improperly repaired combustor cans. They considered the JT8D engines operated by British Airtours to be “low-time” engines, since they were delivered new in 1980, and they had high confidence in their own ability to repair cracks correctly. (None of Pratt & Whitney’s communications specified what constituted a “high-time” combustor can, and British Airways didn’t ask.) Consequently, the engineering department didn’t pass on any of the information about the combustion chamber issues to the maintenance department, and no changes to any maintenance or inspection timelines were made. For components not deemed critical to flight safety, the active policy was to modify inspection and maintenance intervals based on in-service experience, which worked (and still does) the vast majority of the time. Until the disaster in Manchester, combustor can failures were not thought likely to result in a serious accident or incident. Investigators wrote that British Airways was rather unlucky to have experienced such a catastrophic outcome from its very first reported combustor can problem.
British Airways also did not appear to have understood that direct fusion welding of cracks in its combustor cans was not fully restoring their fatigue lives. Cognizant of this fact, 11 other JT8D operators surveyed by the AAIB had developed in-house rules prohibiting weld repair of any combustor can liners containing cracks greater than 76 mm (3 in) in length. Above that level of damage, there was simply no assurance that the fatigue life of the repaired can would be sufficient to prevent failure before the next scheduled inspection. Only British Airways and one other surveyed operator lacked such a limit. For its part, BA told investigators that the imposition of limits not specifically recommended by Pratt & Whitney would always come about as the result of in-service experience, and that it had not operated JT8D engines for long enough to recognize the need for a maximum repairable crack length.
Consequently, British Airways repaired a 160-millimeter crack in combustor can №9, which at other airlines would have been taken as a sign that the cracked liner needed to be replaced. The quality of the repair itself was adequate, but as an attempt to extend the service life of the can, it was like putting a band-aid over a ruptured artery. Once it was put back in service, the degradation of the can essentially picked back up where it left off. It ultimately took only 4,400 more hours, less than half the normal interval between overhauls, for the repaired can to fail.
At that time, the problem of ensuring sufficient fatigue life in repaired components was a major challenge facing the airline industry, and several accidents during that period were traced to premature failures of components due to improperly applied or poorly conducted repairs. The crash of Japan Airlines flight 123, which happened just 10 days before the tragedy in Manchester, also involved this issue. Better quality control has since proved critical to ensuring that repaired components survive until their next scheduled inspection.
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At this point, the technical narrative has been elucidated up to the moment of the explosion as flight 28M sped down the runway in Manchester. But the real story began in earnest only after that, as what should have been a relatively minor incident rapidly escalated into a horrific tragedy that never should have happened.
The progenitor of this catastrophe was the unfortunate collision of the ejected combustor can dome with a fuel tank access hatch on the underside of the left wing. The impact would have been insignificant had the dome struck anywhere else, because calculations showed that its impact velocity was insufficient to breach the lower wing skin. However, the access panel was only one quarter as strong as the surrounding wing skin, and it gave way very easily. This weakness had not previously been considered because neither the lower wing skin nor the access panels were subjected to any particular loading in service, and as such were not required to meet any strength requirements. Nevertheless, had the access panels been designed with the same impact strength as the skin, the accident clearly would not have happened. As such, one of the AAIB’s early recommendations was for the elimination of such weak spots in the fuel tanks.
The destruction of the access panel opened a 271-square-centimeter (42 sq. in.) hole in the underside of the wing, allowing the liberation of a relatively large amount of fuel in a short period of time. This fuel quickly ignited into a dramatic but initially mostly harmless plume of fire trailing behind the wing as the 737 continued down the runway. But investigators found that as the plane came to a stop, the 7-knot wind from the left drove the fire directly into the aft cabin, where it wrapped completely around the airplane, resulting in rapid penetration of the fuselage skin. Models estimated that the skin was likely penetrated not earlier than 5 seconds before the plane stopped, and not later than 20 seconds after. At that time, all 137 passengers and crew were still on board the airplane.
The potentially disastrous influence of a 7-knot wind, which was too light to be of much concern to the crew, was well known to fire experts but was not really appreciated by the aviation industry at the time. The section of the operations manual concerning engine fires contained a single line advising pilots to stop the plane with the fire downwind of the cabin, so that flames would be blown away from the passengers, but this suggestion was not reinforced at any point during training, nor were pilots aware that a wind as light as 1–2 knots can significantly affect the course of a fire’s development. In general, wind was only taken into consideration when handling aircraft fires in exceptionally gusty conditions. There was virtually no chance that the 7-knot wind out of the west would have crossed Captain Terrington’s mind as he steered his plane off the runway onto Link Delta.
Some debate occurred over whether Terrington should have stopped on the runway on principle. According to the operations manual, the proper practice following a rejected takeoff was to stop on the runway and assess the conditions before deciding whether to taxi off of it. Had this been done, the wind would have blown the fire significantly aft rather than toward the cabin, and the time taken to stop the airplane would have been reduced. But in the scenario of a burst tire or birdstrike, which Terrington initially believed to have occurred, there was nothing particularly wrong with clearing the runway right away, especially at Manchester, where they risked blocking the sole runway if they stopped and couldn’t get started. Furthermore, the crew was only informed of a fire 9 seconds after the failure, by which time the decision had already been made. The cockpit voice recording showed that Terrington was engaged in handling the emergency continuously from that point until the moment the plane came to a stop, with no real chances to reconsider his course of action. Terrington himself endorsed this explanation when asked why he chose to turn onto Link Delta even after learning of the fire. In the end, the AAIB called his actions “understandable” and levied no criticism.
Unfortunately, the unforeseen complication of the wind direction greatly accelerated the progression of events aboard the plane and critically reduced the available survival time. Due to the swift penetration of the outer fuselage skin, smoke began to enter the rear of the aircraft as soon as it came to a stop, and open flames likely reached the cabin interior in less than one minute. Most of the passengers were still on board at that point. The first exit to be opened was L1, about 25 seconds after the plane came to a stop, but only 17 people used this exit. The right overwing exit was opened after 45 seconds, and very few people escaped through it before the queue was enveloped by smoke. It took fully 70 seconds to open door R1 because of the jammed slide pack, even though this became the door through which the greatest number of people escaped. By that time the fire had already entered the cabin interior.
However, as in most fire-related disasters, whether on airplanes or in buildings, smoke was by far the biggest killer. Of the 54 people who died inside the airplane, only 6 died due to direct thermal assault, i.e. burning. The rest were killed by toxic gases produced as combustion byproducts of kerosene fuel and aircraft materials, including carbon monoxide, which was detected above fatal levels in 13 victims, and hydrogen cyanide, which was above fatal levels in 21 victims. Other gases often produced in aircraft fires include corrosive irritants such as hydrogen chloride, nitrogen dioxides, Sulphur dioxide, and ammonia; aromatic hydrocarbons, such as toluene, benzene, and styrene, which can cause loss of consciousness and impaired neurological functioning; hydrogen fluoride, which will dissolve your respiratory tract; and acrolein, which causes death at just 10 parts per million. For this reason, the useful survival time once smoke filled the cabin was very limited, and only 47% of those who became enveloped in smoke survived the accident.
Investigators noted that the wind contributed not only to the spread of the fire, but the spread of the smoke as well. Intuitively, air will flow into the airplane mostly through openings on the upwind side, and out of the airplane through openings on the downwind side. When the fire is upwind of the airplane, as it was in this case, the passengers will attempt to evacuate on the downwind side to get away from the fire. In this case, investigators believed that with the L1 and R2 doors open, a positive pressure gradient initially existed whereby smoke-free air entered on the upwind side at door L1, traveled aft through the cabin, and exited on the downwind side at door R2, preventing the smoke from spreading forward. Then, when door R1 was opened, creating a downwind opening at the front of the plane, this fore-to-aft pressure gradient disappeared, at which point smoke rapidly rolled forward through the cabin in the manner observed by many witnesses.
Although the initial failure to open the R1 door thus delayed the entry of smoke into the forward cabin, it had a far more immediate negative impact in that it delayed the start of the evacuation by even longer. Had the R1 door been opened immediately, the evacuation would have commenced as much as 20 seconds sooner, which in the dynamic cabin environment might as well have been an eternity. Furthermore, the fact that only 17 passengers exited via the L1 door, vs. 34 from the R1 door, even though the L1 door was open for longer, suggested that passengers were reluctant to use a door that was on the same side as the fire, and that greater evacuation rates could have been achieved if the R1 door was in use from the beginning. Critically, this delay wouldn’t have happened if the lid of the slide pack hadn’t fouled on the doorframe, so the FAA issued an airworthiness directive mandating changes that would prevent this from occurring in the future.
However, it was noted that having both the L1 and R1 doors open at the same time didn’t improve the exit rate because both doors could only be reached by passing in single file through the same galley bulkhead. The bulkhead was therefore the bottleneck, not the doors themselves. This meant that there were effectively only two available exits, not three, when considering evacuation speed.
Aircraft manufacturers have long been required to demonstrate that their airliners can be evacuated in 90 seconds or less by untrained members of the public using only half the exits. These evacuation tests involve prescribed percentages of children, elderly, and so on, to mimic actual passenger compositions, but they don’t involve smoke or fire. When smoke is present, evacuation speeds decrease markedly, mostly due to the resultant inability to see. Furthermore, these tests don’t encompass scenarios in which the available exits are disproportionately at one end of the aircraft. Therefore, even though half the exits on flight 28M were used, an evacuation time of 90 seconds likely could not have been achieved even under perfect conditions because the L1 door merely absorbed some passengers who could otherwise have used the R1 door, or vice versa, rather than actually increasing the total number of passengers who could evacuate within a given timeframe.
In 1985, it was difficult to test the variables that might have affected survival times. However, a comprehensive 2016 study of survival factors in the Manchester disaster used a computer model of the accident to answer some of the what-ifs proposed by the preceding paragraphs. According to the simulation by Wang, Jia, and Galea at the University of Greenwich, fatalities might have been reduced by 87% if the R1 door had opened properly, due to the earlier evacuation start and likely increased evacuation rate as passengers were less reluctant to leave from this side of the aircraft. This would have allowed many people to exit via the R1 door who in the actual event decided to bet on the overwing exit instead due to the length of the queue for R1/L1. Similarly, had the passengers in row 10 been taught how to open and dispose of the exit door, resulting in its opening within 12 seconds as assumed in certification tests, then overall fatalities would have been reduced by 36%. And if both exits had been opened immediately, the simulation showed that with the known evacuation rates from the various exits but earlier start times, the last passengers could have left the cabin before conditions deteriorated to the simulation’s “incapacitation” threshold, and no one would have died at all. Obviously, the validity of such a simulation can never be fully tested because we can’t go back to 1985 and re-run the real evacuation, but the findings are thought-provoking.
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In addition to the speed with which doors were opened, the original AAIB investigation examined a number of other factors that might have influenced passenger survival.
One notable issue was that the access to the right overwing exit was unacceptably tight. All passengers leaving via this exit had to shuffle through the gap between the cushions of row 10 and the seat backs of row 9, a space that was only 27 centimeters (10.5 in) wide. This was only slightly wider than a normal row on the tightly packed airplane, which had been configured with the maximum allowable number of seats. This made it hard to determine which row was the exit row while blinded by smoke. Furthermore, the exit itself was directly above the cushion of seat 10F, forcing passengers to climb over this seat to reach it. The back of seat 10F was designed with a baulk to prevent it from folding forward and blocking the exit, but in the event this seat partially folded anyway, further restricting access, because desperate passengers climbing over the seatbacks broke the baulk mechanism. In the AAIB’s opinion, the design of this row clearly did not meet British certification requirements, which stated that the use of emergency exits should not require “exceptional agility” and that easy means of access must be provided “at all times, including darkness.”
The AAIB also analyzed the firefighting tactics and noted that fire trucks responded much earlier than required and applied more foam to the fire than assumed during airport certification, while the fire itself involved only about 2,650 L (700 gallons) of fuel, much less than the total aboard the airplane and exponentially less than the amount aboard a 747, which the airport was also certified to handle. And yet, despite these factors, the fire crews were unable to prevent the fire from penetrating the fuselage and killing 55 people. This prompted investigators to write that the “whole approach to aircraft firefighting was called into question by this accident,” but they could not immediately point to any obvious tactical solutions.
Instead, the AAIB examined a number of possible means of extending the window of survival for passengers inside a burning airplane. In their view, existing research into this area was largely misdirected. Most ongoing efforts were aimed at reducing the flammability of cabin furnishings with the goal of delaying the occurrence of “flashover.” In simplified terms, a flashover occurs when combustible materials, such as furnishings, within an enclosed area are heated to the point where they all simultaneously combust. No flashover occurred on flight 28M, probably due to the number of open exits. Nevertheless, prior to the Manchester accident, flashover had been considered the point where the cabin environment transitions from survivable to unsurvivable, and as such, delaying it as much as possible was seen as the most worthwhile goal. Making cabin furnishings more difficult to ignite would advance this goal considerably. However, the AAIB pointed to a growing body of evidence suggesting that in “pooled fuel” type aircraft fires, flashover rarely occurs, and that the factors most directly affecting survivability are the volume of toxic gases produced and the time required for the fire to penetrate the fuselage.
Regarding the time required for fire to penetrate the fuselage, the AAIB touched on the idea of fire-hardening the fuselage itself, a proposal that they felt had not received sufficient attention. They also spent somewhat more time exploring the concept of sprinkler or misting systems that could draw on the plane’s existing water supply to slow the advance of a fire into the passenger cabin. Investigators pointed to preliminary studies that had shown promising results. However, the proposal has never been seriously entertained by the airline industry due to cost and uncertainties about the systems’ effectiveness.
Regarding smoke and toxic gases, the AAIB proposed first of all that cabin furnishings be subject to limitations on the types and volumes of gases that they produce when burned. This view contrasted with the prevailing efforts, which focused on delaying combustion using “fire-resistant” materials that sometimes produced significantly more toxic smoke once they inevitably ignited anyway in the course of an uncontrolled fire.
Secondly, and more significantly, the AAIB expended considerable energy in support of requiring smoke hoods for passengers. The accident airplane had smoke hoods for the crew, which were not used, but none for the passengers. Filtered smoke hoods can extend the survivable window in a smoke-filled environment by as much as 10 to 20 minutes in exchange for relatively small weight penalties and installation costs. By the time the AAIB published its final report, highly effective, light, and cheap smoke hoods had already been developed and tested. Furthermore, investigators argued, the availability of protection against the caustic effects of smoke would make evacuations swifter and more orderly and would facilitate passenger survival during in-flight fires as well. The AAIB also pointed out that emergency track lighting in the floor, which is standard on aircraft today but was in the proposal stage in 1985, would be useless if passengers could not open their eyes due to the irritant effects of smoke — but that this barrier could be eliminated with the provision of smoke hoods.
After several accidents in the 1960s in which large numbers of people perished aboard intact aircraft due to the effects of smoke, the US Federal Aviation Administration proposed that smoke hoods be provided for airline passengers. However, the proposal was withdrawn in 1970 after a number of criticisms were lodged. The most important of these was a study which found that the time required to evacuate an aircraft was noticeably increased when untrained passengers were asked to put on smoke hoods first, an argument that has been repeated in subsequent decades. This argument clearly has merit. However, the AAIB noted that many more people would unquestionably have survived the Manchester accident if smoke hoods were available, given that flashover never occurred and the survivor who later died in hospital was still alive without extensive burns a full 33 minutes after the fire started. Quite intuitively, smoke hoods are probably a net positive when smoke is the primary factor limiting survival times, as it was in this case, and probably a net negative when fire and heat are the limiting factors. But, as the AAIB points out, on average around 80% of victims in aircraft fires die of smoke inhalation as opposed to burning, and by their analysis the time required for heat alone to close the survival window was often many minutes longer, so if all else is taken at face value, then having smoke hoods should save lives overall.* Despite this, smoke hoods for passengers are still not required, nor is there any particular urgency to change that, for reasons that will be examined shortly.
*Note: This is a description of the AAIB’s argument, not an endorsement of requiring smoke hoods.
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In many retellings of the story of British Airtours flight 28M, the conclusion tends to focus on two supposed improvements: the widening of exit rows, and the widening of the bulkhead gap to allow two passengers to pass abreast. However, this story is partly fictitious. Present day US regulations (which often set global standards) do require paths to the overwing exits that are at least 51 cm (20 in) wide, leading to the noticeably roomier exit rows familiar to passengers today. However, regulations still allow a path width as low as 25 cm (10 in), slightly narrower than that on the accident airplane, if there are only two seats in the exit row instead of three. British Airtours therefore could have complied with modern regulations without making any changes to the exit row seat pitch as long as they removed seats 10A and 10F, even though the AAIB in its final report specifically stated that removal of these seats does not solve the overwing exits’ accessibility problems.
Secondly, there is absolutely no evidence that the bulkhead passage on the 737 was ever widened, or that such a thing is even possible. Regulations in 1985 stated that the path leading to exits of the type on the 737 must be no less than 51 cm (20 in) wide, and this is still the case today. Modification of the bulkhead passage on existing aircraft types would also be impractical for structural reasons. Furthermore, although the 57-cm (22.5-in) wide bulkhead passageway on the accident airplane contributed to a passenger logjam early in the evacuation, the AAIB did not recommend that the passage be widened, but rather only that rules in this area be “reviewed.” It does not appear that such a review, if it occurred, led to any changes in standard cabin layouts at all. Furthermore, widening this passage would not have significantly improved the rate of exit utilization because the aisle itself was only 44 cm (17.5 in) wide at its widest, and it’s not practical to widen it enough to allow two-abreast passage without removing huge numbers of seats.
In summary, then, modern airplanes may have slightly wider exit rows, but they don’t have wider bulkheads or aisles, aren’t equipped with smoke hoods, and don’t have sprinkler systems. So what makes planes safer in a fire today than they were in 1985? The answer is, actually, quite a lot.
Although many popular accounts overlook it, the most important direct change as a result of the Manchester accident was arguably a joint FAA/CAA airworthiness directive that required strengthening of fuel tank access panels on several Boeing aircraft in order to prevent penetration by relatively low-energy debris like combustion chamber elements and tire fragments. This was part of a broader industry push to address the problem of large fuel-fed fires at their source — that is, the fuel tanks themselves.
Uncontrolled, fatal ground fires on board intact aircraft are almost invariably the result of fuel tank breaches, whether due to mechanical failures as in this case, or crash landings, as in many others. The greatest success in saving lives from aircraft ground fires has therefore come about not by trying to protect passengers from the fire — a noble goal nonetheless — but rather by preventing fires from occurring at all. Between the 1960s and the 1980s, there were numerous accidents in which smoke inhalation was the primary cause of fatalities, but these have since dropped off so steeply that no major accidents of this type have occurred in the 21st century so far, with only one possible exception, which I’ll discuss in a moment. One way of looking at this improvement is that hardening of the fuel tanks has narrowed the gap between the force required to start a large fuel-fed fire and the force required to destroy the airplane, removing much of the in-between area where a fire might erupt and rapidly overtake an otherwise intact aircraft. This interpretation is supported by the increasing rarity of post-crash fires following relatively low-G impacts. Additionally, in those fuel-fed fires that have erupted, fatalities have been avoided thanks to continued commitment to fire hardening of the fuselage and cabin, preventing fuselage penetration from occurring before the occupants can leave. This is supported by the findings of the University of Greenwich study of flight 28M, which found that a 40-second increase in the time required for the fire to penetrate the fuselage, all else being equal, would have reduced the expected number of fatalities from 55 to just one.
The only possible exception to this nearly unbroken record is the 2019 crash of Aeroflot flight 1492 in Moscow, Russia, involving a Sukhoi Superjet 100, in which 41 of the 78 occupants died in a fire following a survivable crash landing on the runway. The final report on this accident has not yet been released at the time of writing, and no analysis of the survival factors has been published, so it’s not yet possible to assess the primary causes of death or the length of the window of survival (although it was certainly very short). However, survivors of the Moscow crash described similar phenomena to survivors of the British Airtours accident, including queues for the sole available exit and thick smoke that suddenly rolled through the cabin. Given the intensity of the fire, it’s also worth noting that smoke hoods in this accident almost certainly would have been counterproductive.
The crash of flight 1492 appears to have slipped through the safeguards preventing catastrophic ground fires due to the unique nature of the crash landing, which featured two bounces and two separate impacts each in excess of 5 vertical G’s. The first 5-G impact destroyed the landing gear, which normally absorbs impact forces, allowing the second 5-G impact to be transmitted directly to the fuel tanks, resulting in mass liberation of fuel and an enormous fire that visibly penetrated the fuselage skin before the airplane even came to a stop. This event is a reminder that the worst case scenario can still occur and that continued efforts to improve evacuation times and survival windows are not necessarily misplaced.
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In the end, even though some of the most-cited safety improvements never actually came about, the Manchester runway disaster nevertheless proved to be a turning point in the fight to prevent needless deaths in aircraft ground fires, and it would be wrong to downplay its relevance. If nothing else, the infamous events aboard flight 28M galvanized the industry to take the problem seriously, adding fuel ever since to countless tiny battles that collectively make a big difference. The relative infrequency of similar accidents today ought to speak for itself.
For those who survived the nightmare in Manchester, this legacy of improved safety has been crucial to their efforts to understand a disaster that seemed so fundamentally unnecessary. When so many people die aboard an intact airplane with a prompt fire rescue response, survivor’s guilt is magnified by the nagging sense that there must have been some mistake, some gross human error to explain the horrific outcome. According to his family, Captain Terrington was haunted by the disaster, speaking of it almost every day until his death in 2016, always wondering if there was something more he could have done, some magic solution that he should have seen but did not. Knowing what we know now, a pilot in his position today might have some chance to avoid a similar outcome. But with the knowledge and resources available to him in 1985, there was little hope that he could have, through some mysterious foresight, steered away from the winds of tragedy. The best salve for wounds like his is not to dwell on versions of the past that didn’t happen, but to take to heart the lessons of the one that did.
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Don’t forget to listen to Controlled Pod Into Terrain, my new podcast (with slides!), where I discuss aerospace disasters with my cohosts Ariadne and J! Check out our channel here, and listen to our latest episode, in which we break down the incredibly poor decision-making aboard Pinnacle Airlines flight 3701. Alternatively, download audio-only versions via RSS.com, or look us up on Spotify!
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Note: this accident was previously featured in episode 61 of the plane crash series on November 3rd, 2018, prior to the series’ arrival on Medium. This article is written without reference to and supersedes the original.
