Birds of a Feather: The crash of Overseas National Airways flight 032
On the 12th of November 1975, a DC-10 loaded with airline employees bound for Saudi Arabia struck a flock of seagulls while taking off from John F. Kennedy International Airport, causing the №3 engine to violently explode. As flames burst forth from the ruined engine, the pilots attempted to reject the takeoff, only to discover that their hydraulics were failing, their wheels were damaged, and there was no way to stop the fully loaded wide body jet before the end of the runway. In a last ditch effort to avoid colliding with a blast fence, the pilots attempted a high-speed exit onto a taxiway, but in the process the landing gear collapsed, the fuel tanks ruptured, and the plane skidded to a halt, surrounded by flames.
In the end, although the aircraft was quickly consumed by fire, all 11 crew and 128 passengers — most of them trained flight attendants — managed to escape with only a few minor injuries. For safety authorities, however, the crash raised several alarm bells. For one, the №3 engine had disintegrated so utterly that major internal components were thrown more than 300 meters from the runway — something which should never happen due to a mere bird strike. Why did the engine fail so catastrophically? And why were the pilots unable to safely stop their speeding aircraft? Answering these questions was the only way to ensure that the next accident, perhaps involving a full load of untrained passengers, would not end in tragedy. And indeed, although the investigators and the engine manufacturer disagreed about some of the fundamental causes of the near-disaster, a bizarre yet plausible sequence of events was eventually established, leading to important safety improvements in the disparate fields of jet engine design and airport wildlife management.
In 1973, the New York-based cargo and passenger charter airline Overseas National Airways made the most ambitious purchase in its history, taking delivery of two brand new wide body McDonnell Douglas DC-10s. Joining a much larger fleet of DC-8s, the DC-10s were destined for the same job as every airplane owned by Overseas National Airways, or ONA — not scheduled passenger flights, but “supplemental” services, including large-aircraft charters and lease arrangements.
ONA operated on a contract basis, usually with other airlines and often with ONA crewmembers as part of the package. One of ONA’s most lucrative markets was the Hajj, the annual pilgrimage to Mecca which all Muslims with means are required to make at least once in their lives. In the 1970s, the Hajj was booming, and so were the so-called Hajj flights: whereas only 7% of Hajj participants arrived by air in 1950, this proportion had grown to a majority by 1970, and only continued to grow as the decade wore on. ONA had been cashing in on the boom for some time, and that the DC-10s would carry pilgrims to Mecca was envisioned from the very beginning.
In 1975, the Hajj was scheduled to run from November 27 to December 6, in accordance with the Islamic lunar calendar, and at ONA, preparations were in full swing by early November. With contracts to carry pilgrims on five of its DC-8s and both DC-10s already in place with various Middle Eastern airlines, ONA faced the daunting task of rounding up and shipping abroad all the equipment and personnel it would need for the multi-week operation. Most of the selected ONA crewmembers were to be brought across the Atlantic in a single trip aboard one of the DC-10s, registration N1032F, along with a large quantity of paraphernalia. This included spare parts, maintenance equipment, cabin consumables, and more, along with a full roster of pilots, flight attendants, and mechanics, sufficient to keep all seven airplanes moving at all hours of the day and night. Departure of the crew ferry flight was scheduled for November 12, and the employees selected for the operation would certainly have had reason to mark their calendars: indeed, the Hajj tour of duty was considered an exciting annual tradition at ONA, and most were probably very much looking forward to it.
At 6:00 sharp on the morning of November 12, 1975, 139 ONA employees reported to the company dispatch office at New York’s John F. Kennedy International Airport, and from there proceeded to the aircraft. Eleven of those employees were on duty, including the three members of the flight crew. In command was 55-year-old Captain Harry Davis, known to his friends and colleagues as “Stinky,” a veteran airman who had accumulated over 25,000 flying hours over a lengthy career that included 24 years at Overseas National Airways. Joining him were 52-year-old First Officer Raymond Carrier — also no rookie, with 14,500 hours under his belt — and 44-year-old Flight Engineer Jack Holland, whose 12,000 hours made him the least experienced member of the crew, although the bar was extremely high. As they prepared for the flight, they were also joined by DC-8 pilot Ben Conatser, who brought with him a newly purchased sound movie camera. Years later, Conatser would recall that he asked the crew for permission to film the takeoff and landing from inside the cockpit, to which they replied, “Okay, no problem — just film our good sides.”
By the time all the passengers and cargo had been loaded and the plane was ready to taxi, it was past 12:00. It had been raining off and on all morning, and although the rain had stopped for now, the runway was visibly wet. On top of that, the plane was 1,000 pounds (450 kg) over its maximum takeoff weight of 555,000 pounds (252,000 kg), thanks not only to the heavy equipment on board, but also the 235,000 lbs (107,000 kg) of fuel required for the transatlantic flight to Frankfurt, West Germany, where a scheduled fuel stop was planned before continuing to Jeddah in Saudi Arabia. The takeoff would only be legal because the lengthy taxi across the vast expanse of JFK Airport was predicted to burn 2,000 lbs (900 kg) of fuel, bringing them down to just under the maximum takeoff weight by the time they reached the runway.
Because the plane was so heavy, and because the wet runway would further increase their required stopping distance in the event of a rejected takeoff, the pilots decided that they wanted to use the longest runway at JFK, which at that time was runway 13 Right. At 14,572 feet from threshold to threshold, this runway was nearly long enough to land the Space Shuttle, and there was no question that a fully loaded DC-10 could accelerate and stop safely before the end, even if the runway was wet. However, due to noise considerations, runway 13R had not been in use for several hours, and the pilots had to make a special request to air traffic control for permission to take off on what was considered a “non-conforming” runway. The permission was granted, however, and shortly before 13:00, Overseas National Airways flight 032 lined up at the threshold, ready to depart.
At about 12:55, with Brian Conatser’s movie camera rolling in the cockpit, the controller’s voice came over the radio: “…[Wind] one three zero, cleared for takeoff…”
“One three zero, cleared for takeoff,” Captain Davis read back.
As the pilots completed the final items, the movie camera captured their undifferentiated voices: “Looking good… one three two… parking brakes released…”
“Max power, please,” Captain Davis ordered.
“You gonna set your power?” someone asked.
The thrust levers were pushed forward, the DC-10’s three powerful General Electric CF6–50 engines spooled up to takeoff power, and within seconds they were away. The plane accelerated normally, and as First Officer Carrier scanned the instruments, nothing appeared to be amiss. Reading off his airspeed indicator, he called out, “One hundred… knots!”
At almost that exact moment, Captain Davis suddenly spotted a massive flock of at least 100 seagulls gathered on the runway, dead ahead. Before his eyes, the startled flock launched into the air, turned, and circled directly into the path of the speeding DC-10.
“Son of a bitch,” Davis exclaimed. “Bird patrol! Watch the EGT’s!”
Fearing that the seagulls could be sucked into the engines, Davis wanted the First Officer and Flight Engineer to monitor the engine exhaust gas temperatures, or EGTs, for any sign of fluctuations or overheating. If such indications were detected, it would signal that the engines had been damaged, and that he would need to attempt a high-speed abort.
A split second later, flight 032 plowed headlong into the flock of panicked seagulls. A cacophony of heavy bangs and thuds filled the cockpit as dozens of birds slammed into every conceivable surface. The mass seagull slaughter was heaviest at the №3 engine, affixed to the right wing, where several birds struck the inlet cowl and bounced straight back into the fan, which was spinning at over 3,700 RPM.
As soon as he heard the bird impacts, Captain Davis decided to reject the takeoff, pulling back power and slamming on the brakes. At the same time, the №3 engine exploded, sending shrapnel flying in all directions. The fourteen spinning compressor disks from the high pressure compressor burst forth from the engine and were launched high into the air, from which some of them crashed down onto a Pan Am storage shed nearly 300 meters left of the runway, setting it ablaze. Moments later, large portions of the engine cowling, fan rotor section, inlet, compressor case, and central shaft departed the airplane, leaving a trail of debris strewn down the runway for several hundred meters. The separation of what amounted to almost half the engine also severed fuel lines in the engine pylon, causing fuel to pour out at a rate of about 600 liters per minute, whereupon it immediately ignited.
As soon as the engine failed, the master caution light illuminated and the master warning sounded, prompting someone to call out to the Flight Engineer, “Jack, your number three is acting up.”
Seeing the same indications, Flight Engineer Holland declared that the №3 engine had been “lost,” and moments later a fire alarm sounded, warning of a fire in that engine. First Officer Carrier and Flight Engineer Holland both tried to close the fuel shutoff lever, but the lever was stuck and refused to move. Thinking quickly, Holland pulled the emergency fire handle instead, cutting off fuel and activating the engine fire extinguishers. The №3 engine fuel pumps immediately stopped, but the fire was already well-established, and the extinguishers, if they were even still attached, had no effect.
At the same time, as pieces of the engine ripped away, several items struck and damaged the tires on the right main landing gear, causing them to deflate. Flight Engineer Holland also noticed that the №3 hydraulic system, whose pumps were powered by the destroyed №3 engine, was inoperative, leading to a loss of power in one of the plane’s two redundant braking systems. The failure also meant that two of the spoiler panels on the right wing, which help force the plane down and improve braking effectiveness, could not be deployed.
Although the pilots estimated that the №3 engine was shut down within seven seconds of its failure, the situation only continued to escalate. In the cabin, passengers stared in alarm at the fire pouring from the ruined engine, which was so hot that the windows nearest the blaze immediately began to melt. And up front, the pilots were beginning to feel that something was wrong with the brakes: although everything had seemed normal for the first few seconds, it was now clear that their rate of deceleration was slowing, as though their braking power was bleeding away. Although the DC-10 was certified to decelerate safely even with the loss of braking action resulting from the failure of one hydraulic system, the problem was exacerbated by the failure of the №3 thrust reverser, the inoperative spoiler panels, the wet runway, and at least three failed tires on the right main landing gear, which were now sliding across the ground rather than rolling, rendering their brakes effectively useless.
At first, Captain Davis thought that even with all these failures, the DC-10 would stop before the end of the runway, but as the rollout dragged on, it soon became clear that they weren’t going to make it. And to make matters worse, there was no overrun area at the end of runway 13R. The departure end was occupied by the threshold of the reciprocal runway 31 Left, which was backed up against the side of the perpendicular runway 4 Right. To protect aircraft on runway 4R from the powerful jet blasts of aircraft taking off on runway 31L, a heavy blast fence had been erected between the two, directly in the path of the speeding DC-10. It was immediately obvious that a collision with the reinforced fence would cause serious damage to the aircraft, and Captain Davis had just seconds to come up with some way to avoid it.
In that moment, he decided that his only choice was to attempt a high-speed exit onto taxiway Z, which angled off the end of runway 13R to the left at about a 50-degree angle. With the taxiway fast approaching, Davis steered hard left, cutting the corner onto the taxiway at a speed of around 40 knots. Most of the tires on the right main and center main landing gears burst, and sparks flew as bare rims scraped against asphalt, before the plane rumbled off onto the grass, crushing a runway light. Decelerating heavily, the DC-10 skidded across the verge, crossed taxiway Z, and lost its right main landing gear, causing the right wing to strike the ground as the plane slid to a stop just short of an airport communications array. The center and left main landing gear bogies also collapsed as the plane ground to a halt, leaving the DC-10 with its tail on the ground and its nose in the air.
When the right wing struck the ground, the remains of the №3 engine punched up through the wing and ruptured the fuel tanks inside, causing a massive fuel spill which greatly accelerated the fire. Within seconds, flames and smoke surrounded the aft fuselage area, from which they began to enter the cabin. But among the passengers, there was no panic — the vast majority were flight attendants who had spent their careers training for this exact scenario. Although the public address system was damaged in the crash, hindering the pilots’ attempts to order an evacuation, the on-duty cabin crew took matters into their own hands and opened the exit doors without being asked. The L1 door on the left side of the forward galley was the first to be opened, but it was blocked by smoke billowing from underneath the plane, so the cabin crew hurriedly opened the R1 door on the right side instead. The slide deployed, and the passengers began a rapid but orderly exit, leaving their belongings behind, forming a line, and jumping down the slide without hesitation, exactly as they had been trained to do.
No one even considered using the aft exits, which were surrounded by fire, and the overwing exits were also out of commission. All 129 passengers were forced to exit through the R1 door — a nightmare scenario on a normal passenger flight, but a cabin full of flight attendants made it look trivial. Within a very short period, everyone was out.
Meanwhile in the cockpit, the force of the impact had thrown cameraman Ben Conatser to the ground, causing him to lose his grip on the camera. As he peeled himself off the floor, the pilots cut fuel to all the engines, and First Officer Carrier observed a huge fire out his window. Realizing the need to abandon ship, the pilots glanced back into the cabin, but saw that passengers were still streaming through the R1 door, so they decided not to hold up the queue, choosing instead to open the First Officer’s window and deploy the emergency escape rope. All three flight crew members rappelled down to the ground using the rope, while Conatser grabbed the film out of his camera and followed the other passengers out the R1 door. He was among the last to leave the plane.
Although firefighters arrived within a minute of the crash, the blaze proved difficult to tackle due to the large amount of spilled fuel, much of which had flowed through a storm drain and was collecting underground. Almost as fast as the firefighters, arriving within 10 minutes, was Overseas National Airways CEO Steedman Hinckley, who allegedly had to be restrained from approaching the burning plane in search of more people who might be on board.
No one was initially sure whether all the passengers and crew made it out, but a headcount soon brought miraculous news: thanks to the speedy and orderly evacuation, all 139 people on board had escaped with their lives. Six crewmembers and 27 passengers were injured, but the injuries were minor; the most serious was probably incurred by First Officer Carrier, who sprained his foot when he dropped off the cockpit escape rope.
In the end, the airplane was a total loss, as the fire burned for 36 hours before firefighters managed to eliminate its underground fuel source. By the time it was over, all that remained of the DC-10 was its tail, its left wingtip, and a pile of charred rubble. Nevertheless, the survival of everyone on board was the top story, and one New York area newspaper proclaimed that “death took a holiday.” Overseas National Airways expressed its own thoughts in a letter to employees the next day, which stated, “Of course, the loss of such a valuable and important aircraft creates problems for ONA, but such matters are overshadowed by our sense of relief and gratitude for there being no serious injuries.”
As investigators from the National Transportation Safety Board arrived on the scene, they clearly recognized the potential for the crash to have been much worse. If the same events had happened to a DC-10 with a full load of untrained passengers, fatalities would have been likely. The airplane involved in the accident was at its maximum takeoff weight mostly thanks to equipment; the passenger cabin, by contrast, was less than half full, and the occupants were mostly disciplined enough to avoid shoving, hesitation, or grabbing hand luggage. On the other hand, trying to evacuate 300 panicked people, including children, seniors, and people with disabilities, many of them refusing to part with their baggage, all through a single exit, would have been a truly daunting task.
This fact underscored the need to find the cause and take corrective measures before a similar accident could happen again. The search for answers began on runway 13R at JFK, where investigators noted a wide range of debris and damage. In the area just before the plane’s final resting place, streaks and gouge marks showed that by the time the aircraft left the runway, four tires had been entirely lost, and four more had deflated. Farther back, pieces of the №3 engine were strewn a considerable distance along and beside the runway, including the series of rotating disks from inside the high-pressure compressor, which compresses incoming air before its entry into the combustion chamber. The first two disks were found on the runway, while disks from stages 3 through 13 were found about 300 meters to its left, where they had struck and damaged the Pan Am storage shed, mentioned earlier, along with a tractor stored inside. The stage 14 disk was never found.
Closer to the start of the debris trail, investigators also found major structural components from the №3 engine, along with the carcasses of about 20 dead seagulls, a scene of carnage stretching for several dozen meters. Damage and residue on parts of the №3 engine indicated that an unknown number of additional birds, perhaps five or six, had been ingested into the fan, where they were presumably turned to a fine mist. Investigators also recovered the fan, which pulls air into the front of the engine, and found that several fan blades had broken due to impacts from heavy objects, presumably seagulls.
The problem was that this kind of damage to the fan should never lead to the catastrophic disintegration of the engine. The structural failure of the engine itself was what severed the fuel lines and started the fire, and without the fire, the accident would have been far less dangerous to all involved. So what made it come apart so violently?
Although the engine was certified to withstand the failure of several fan blades, investigators first needed to prove it. With help from General Electric, the manufacturer of the CF6–50, two test engines were used to simulate the forces experienced by the accident engine when the partial separation of several blades unbalanced the rapidly spinning fan. Rotating components on turbofan engines are built to extremely precise weight distribution standards, and when rotating at 3,700 RPM, any disruption to this balance can result in immense shear forces — but were they enough to rip the engine apart? In the end, the test results indicated that the answer was no. Even with an imbalance 25% greater than that experienced by the accident engine, the test engine stayed in one piece, even though it was severely damaged — exactly as GE had asserted it would.
One possible clue to the mystery lay in the remains of the compressor case, a hardened structure which surrounds the high pressure compressor section and is designed to prevent the rotating components inside from escaping in the event of a failure. The case had fractured into several pieces and was deposited on the runway early in the debris trail, indicating that it was one of the first parts to come off, and was followed by the fan disk and inlet structure several seconds later. Furthermore, tension failures of the bolts holding it together, along with the deformations of the compressor case itself, indicated that it probably failed due to an internal overpressure event. This was further evidence against the fan imbalance theory, because even in those tests where some compressor case bolts failed, they always failed in shear, and never in tension. Nor was there any plausible way to imagine a fan imbalance causing such a severe overpressure event inside the high pressure compressor — or was there?
When airflow into a turbine engine is disrupted, the engine can stall and surge, as excess pressure builds up in the high pressure compressor before bursting forward into the low pressure compressor, opposite to the normal direction of airflow. However, this kind of overpressure is common in service and should never lead to the catastrophic failure of the reinforced compressor case. The only way to cause that level of damage would be to detonate some kind of explosive material inside the compressor.
Although the official NTSB report and its appended documents don’t indicate any disagreement over the source of this explosive material, an official summary of the investigation written by the Federal Aviation Administration states that there was, in fact, a significant divergence of opinion between the NTSB investigators and General Electric. According to the FAA, GE initially believed that the most plausible accelerant which could cause an explosion in the high pressure compressor section was aviation fuel. As for how it got there, GE suggested that the explosive failure of the №3 wheel and tire, located in the forward right position on the right main landing gear, had launched rubber fragments at high speed into the side of the engine, penetrating the cowling, severing fuel lines, and damaging the compressor case. Fuel was then able to enter the compressor section, where it exploded, destroying the engine. The NTSB report does mention a piece of the engine cowling which made contact with a fragment of the №10 tire, but the report implies that this contact occurred after the engine had already begun to disintegrate, and that pieces of the failing engine damaged the tires, rather than the other way around.
Furthermore, according to the FAA, GE claimed that the ingestion of birds could not possibly have caused such extensive damage to the fan blades, and that the damage must have been caused by pieces of the disintegrating №3 wheel, which were sucked into the engine. The subsequent ingestion of birds was, in GE’s view, a coincidence.
The National Transportation Safety Board apparently refused to buy this explanation, which they did not even consider worth mentioning in their official report. Instead, the NTSB pointed to later tests by General Electric that revealed a surprising possibility: that the overpressure event inside the high pressure compressor section was, in fact, a dust explosion.
When the fan rotor was thrown off balance by the failure of several blades, it displaced the central shaft, to which the fan and the low pressure compressor disks were attached. The fan and the compressor disks were thus rotating out of true, with a pronounced wobble. Because jet engine fans and compressor disks are built with extremely tight tolerances to ensure smooth airflow, this imbalanced rotation resulted in near-constant contact between the tips of the blades and the surrounding abradable rub shroud.
The interior of the fan case, which contains the fan (and of the compressor case, which contains the compressor disks), is made up of a light, easily worn material, designed to rub off when contacted by the blades. Because these rapidly rotating disks have gyroscopic characteristics — that is, they tend to resist changes to their plane of rotation — any sudden movements during normal flight tend to cause the engine structure to move while the disks try to stay in place, resulting in momentary contact between the blade tips and the surrounding fan or compressor case. Covering the interior of the case with an easily abradable material ensures that the blades are not damaged when this occurs. On the GE6–50 engines installed on the accident DC-10, the material used for this abradable rub shroud was a form of epoxy resin.
Late in the investigation, tests by General Electric revealed an interesting and unexpected characteristic of this epoxy rub shroud. When the fan was subjected to a severe imbalance, consistent with the partial loss of several fan blades, the “wobbling” of the damaged fan resulted in sustained, rather than momentary, contact between the blade tips and the rub shroud. As the fan blade tips and low pressure compressor blade tips ground against their respective rub shrouds, the epoxy material was scraped away in the form of a fine powder, which was then sucked backward into the high pressure compressor. Real-world experiments revealed that certain concentrations of this powder would auto-ignite, triggering an explosion, when exposed to the high temperatures and pressures inside the compressor. The mechanism was similar to that involved in grain silo explosions, which occur when suspended grain dust creates a flammable fuel-air mixture that ignites when exposed to a spark.
Further testing revealed that the particular epoxy resin used for the rub shroud in the CF-6 series of engines ignited more explosively and at lower temperatures and pressures than other materials commonly used for rub shrouds. Furthermore, a specific range of fan imbalance levels was required in order to produce a flammable concentration of dust in the high pressure compressor. A fan with less damage would not produce enough dust to permit auto-ignition, while a fan with substantially more damage would produce too much dust, also preventing ignition. The damage to the accident engine, however, fell right in the sweet spot: the damaged fan wobbled just enough to wear away the shroud material at the correct rate to produce a fuel-air mixture that would auto-ignite under the specific conditions inside the high pressure compressor at that moment. Incidentally, this was probably why the phenomenon had not been previously detected.
The NTSB believed that the explosion of the powderized rub shroud material was sufficient by itself to cause the catastrophic failure of the high pressure compressor case, resulting in disintegration of the engine. According to the FAA summary, GE believed that such an explosion would damage the compressor case, but could not by itself explain its total failure, insisting that simultaneous damage to the case from flying tire debris must have pushed it over the edge. Nevertheless, in the end the NTSB concluded, apparently over GE’s objections, that multiple bird impacts damaged the fan blades, resulting in a fan imbalance that wore away the rub shroud, which in turn triggered a dust explosion that destroyed the high pressure compressor case and fatally weakened the engine structure.
All of this having been said, a few questions remained, including the reason for the pilots’ inability to stop the plane. The NTSB did not spend much time analyzing the loss of braking power due to a lack of specific data, but investigators did conclude that the multiple tire failures, the wet runway, the loss of reverse thrust from engine 3, and the failure of the №3 hydraulic system collectively prevented the plane from being safely stopped in the available runway length. Although the cockpit voice recorder was destroyed in the lengthy post-crash fire, the cockpit footage captured by Ben Conatser allowed investigators to reconstruct the pilots’ actions, and on that basis the NTSB determined that they did everything right to ensure a safe outcome. The final report highly praised the pilots and all the other crewmembers for their conduct during the emergency and the post-crash evacuation, including Captain Davis’s decisions to quickly reject the takeoff and to avoid a collision with the blast fence once it became clear a runway overrun could not be averted.
The NTSB report spent somewhat more time analyzing the effectiveness of JFK Airport’s efforts to keep birds away from airplanes. The hazard of bird strikes has been recognized since the very beginning of powered flight, and although JFK Airport had bird control measures in place, in this case they were clearly ineffective. The presence of birds during the accident takeoff was not really a surprise: after all, runway 13R runs for its entire length along the shore of Jamaica Bay, a swampy inlet popular with seabirds. Furthermore, the runway had not been used in several hours, and in the absence of takeoffs or landings to scare them away, the birds had claimed the strip as their own. These factors made the presence of birds on the runway at that place and time rather predictable, and investigators criticized the Port Authority of New York and New Jersey, which runs JFK Airport, for not sending out a bird patrol to scare away birds before opening the previously closed runway to traffic.
Scaring birds off a runway before opening it is one of several basic measures which should form a part of any major airport’s formal bird mitigation protocol. The airport certainly had the means to do so — in fact, as part of its bird control program, seven acoustic cannons were positioned along runway 13R to scare birds, and the airport also owned a vehicle equipped with a sound system capable of playing tape recordings of bird distress calls. The bird control program featured six part-time employees and one full-time employee whose sole job was to remove birds using methods including periodic shotgun blasts, installation of anti-bird spikes in popular resting spots, and removal of food sources such as rodents, ponds, vegetation, and garbage dumps. The task was, however, quite daunting for one person — after all, there were several garbage dumps in the area which tended to attract seagulls, as well as numerous wetlands, marshes, and even a federally protected bird sanctuary in nearby Jamaica Bay.
The fact that insufficient resources were being allocated to bird control first came to the attention of the FAA in early 1975, when a study found that the rate of bird strikes at JFK so far that year had increased in comparison to the same period in 1974. As a result, the FAA convened several meetings with the Port Authority in order to encourage the implementation of a “more aggressive” bird control program. These meetings resulted in the introduction of a 30-day bird reduction test program in July 1975, which featured a Port Authority employee and a police officer armed with a shotgun who patrolled for birds between 12:00 and 20:00 up to seven days a week. After September 15th, however, the operation was scaled back, eliminating the Port Authority employee and reducing the coverage to five days a week.
Shortly afterward, bird encounters began to spike. There were 7 serious bird strikes resulting in five damaged engines during the month of October, in comparison with 1–2 serious bird strikes per month from July to September. Alarmed by the increase, on November 1st the Port Authority expanded the bird control program to include two police officers with shotguns working two overlapping shifts, one from 06:00 to 14:00, and the other from 10:00 until dusk. Additional vehicles armed with tape recordings of bird distress calls were also being prepared, and one was operational on the day of the accident. And yet, despite all of these measures, none were used to clear birds from runway 13R before flight 032 took off. The Port Authority had apparently invested in the required equipment and personnel, but neglected intangibles like procedures and discipline.
As a result of the accident, several safety changes were made across multiple areas. In the field of jet engine manufacturing, General Electric replaced the epoxy rub shrouds in its CF-6 series engines with less flammable aluminum, and the FAA required other manufacturers to do the same. In other areas, the accident and others like it led to a series of FAA meetings aimed at revising and updating standards for aircraft tires, wheels, and braking systems, which culminated in new rules issued in 1979. And in the interest of wildlife control, the Port Authority of New York and New Jersey launched a campaign to remove features near JFK Airport that were attractive to birds, and the airport began requiring a “bird sweep” any time a runway’s status is changed from inactive to active. Lastly, it’s also worth noting that the blast fence at the end of runway 13R has been removed in order to comply with modern regulations requiring clear areas for runway overruns. Planes on runway 4R are now protected from jet blasts by sheer distance, as the threshold of runway 31L was simply moved about 1,000 meters away down the strip.
Nevertheless, the apparent disagreement between the NTSB and GE over the fundamental causes of the accident does not appear to have been resolved. In the interest of completeness, it’s worth putting these arguments in perspective. Although GE presented evidence of what it claimed was “hard body” damage to the fan blades prior to bird ingestion, its claim that the birds could not have caused such severe fan blade damage deserves some skepticism. At the time the CF6 series of engines was first certified in 1968, there was virtually no understanding of how high-bypass turbofan engines with large fans behave when ingesting birds of various numbers and sizes. Federal regulations did require bird ingestion tests, but the tests were designed for low bypass turbofans with a smaller inlet area, reducing the maximum number of birds which can plausibly be ingested at one time.
Evidence indicates that the accident engine might have simultaneously ingested as many as five or six seagulls, and an examination of the carcasses on the runway revealed that the average weight of the birds was 3–4 lbs (1.4–1.8 kg), while the largest bird weighed a whopping 5 lbs (2.3 kg). However, under regulations existing at the time, the CF-6 series of engines was only required to demonstrate that it could be safely shut down after ingesting a single bird of this size. Ingesting several large birds was far outside what the engine was certified to withstand, and the available evidence does not make clear on what basis GE concluded that such an event could not possibly cause the observed fan blade damage.
It’s also worth noting that a catastrophic tire failure occurring at almost the exact same moment as a major bird strike is a wild coincidence if proven, but a suspicious one if not. Had the NTSB also concluded that these events were a coincidence, then there would be little doubt, but the NTSB did not reach such a conclusion, based on evidence which suggested that the bird strike and the engine damage were clearly related. As a result, GE’s contention that the engine damage was actually caused by pieces of the landing gear — which was manufactured by a third party — smells somewhat like an attempt to avoid liability. Engines ingest birds all the time, and if GE’s engines were uniquely vulnerable, then that was a financial risk; on the other hand, no engine can withstand ingesting large pieces of landing gear wheels, in which case GE is off the hook. Again, this would be entirely alright if everyone agreed on the facts, but GE was alone in its position.
Thankfully, however, the manufacturer’s contentions did not stymie the march of progress, and over the years since, bird ingestion requirements have been strengthened substantially. According to the latest regulations, which were introduced in 2007, high bypass turbofan engines with large inlet areas, like those typically used on wide body airliners today, must be capable of ingesting multiple birds weighing up to 5.5 lbs (2.5 kg) with a loss of thrust no greater than 50%. Had the CF-6 series been tested to this standard, we would have a better understanding of whether the bird strike on flight 032 could have caused the observed damage — and if it could have, then the engine likely would not meet modern certification requirements.
Even as experts continued to debate the causes, for those involved in the accident, life simply kept going. Two days after the crash, most of those who were on flight 032 boarded a new DC-10, leased by ONA on short notice, and proceeded to Saudi Arabia, as though nothing had happened. In retrospect, however, many ONA employees came to believe that the crash was the beginning of the end. Less than two months later, in January 1976, ONA’s other DC-10 was lost in a non-fatal landing accident in Istanbul while on lease to Saudi Arabian Airlines, dealing a devastating blow to the relatively small company. Records indicate that ONA initially tried to press on, purchasing three more DC-10s in 1977 and 1978, but in October of that year the company’s owners elected to liquidate it, and the planes were sold to various airlines around the world. In an ironic twist of fate, two of the three new DC-10s were also lost in crashes within five years, one as Spantax flight 995, a domestic flight within Spain that crashed on takeoff in 1982, and the other in a non-fatal runway collision in Anchorage, Alaska in 1983 while hauling freight for Korean Air Cargo. Only the fifth and final DC-10 survived, eventually landing at FedEx, where it remained in service until 2022.
Although ONA’s DC-10s were apparently cursed from the very beginning, the crews who flew them still look back fondly on the now long-vanished airline, and the dramatic crash at JFK Airport may have only strengthened that bond. It was the ultimate vindication of their own training and foresight, an accident whose occurrence was outside their control, but which was handled in the best possible way, with competence, skill, and professionalism, leading to an enviable outcome. Death truly did take a vacation that day, but it was the ONA staff who paid for the package.
Support me on Patreon (Note: I do not earn money from views on Medium!)
Visit r/admiralcloudberg to read and discuss over 240 similar articles