Accident Overview

History of Flight

Photo of JFK. Runway 13R is the long runway at the left edge, paralleling the shoreline. An airplane on Runway 13R would be moving directly toward the viewer.
Photo of JFK. Runway 13R is the long runway at the left edge. An airplane on Runway 13R would be moving directly toward the viewer.
Photo copyright Kenneth C. Iwelumo - used with permission
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On November 12, 1975, an Overseas National Airways, Inc. (ONA), McDonnell-Douglas DC-10-30 operating as Flight 032, crashed while attempting to take-off from runway 13R at the John F. Kennedy International Airport, Jamaica, New York. It was a non-revenue flight with 128 passengers and a crew of 11, all ONA employees. It had a maximum load of fuel and the aircraft weight was 556,000 pounds at pushback (Maximum allowable takeoff gross weight was 555,000). The flight crew taxied for 3 miles at 12 miles per hour before reaching the beginning of the runway.

Since the airplane would be at maximum takeoff gross weight at the beginning of the takeoff roll, the captain requested and received permission to use runway 13R.  He requested 13R because this runway was the longest runway at JFK. At the time of this request, runway 13R was inactive because of wind and noise considerations. ONA flight 32 would be the first airplane to operate from runway 13R on the afternoon of the 12th. It is important to note that runway 13R is adjacent to a saltwater bay and is near the shoreline its entire length.

During the take-off roll, after the aircraft passed 100 knots, the captain saw a large flock of birds standing on the runway. The flock became airborne and circled back in front of the approaching airplane. The flight crew heard the birds striking the aircraft, and the captain estimated that the aircraft was struck by about 100 birds. He believed the takeoff decision speed (V1) had not yet been reached, and he rejected the take-off. As the engines went into reverse thrust, the flight engineer stated that they had "lost" the number 3 (wing mounted) engine. The numbers 1 and 2 engines attained normal reverse thrust.

The flight engineer noticed that the number 2 brake system pressure had dropped to zero. The number 2 brake system is powered by the number 3 hydraulic system, which is driven by the number 3 engine. The number 1 brake system pressure remained normal at 3000 psi. The flight engineer advised the captain that the brake system was available.

Illustration of DC-10 Engine Locations
Illustration of DC-10 Engine Locations
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Diagram of CF6-6 Engine Wings Installation
Diagram of CF6-6 Engine Wings Installation
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Within seconds, the fire warning light illuminated for the number 3 engine. The flight crew attempted to shut down the number 3 engine by closing the fuel shutoff lever, but the lever could not be moved. The flight engineer then pulled the engine fire handle to shut down the engine, close the fuel shutoff valve, and activate the fire extinguishing units to the engine. The crew estimated that the number 3 engine was shut down within seven seconds after they realized the engine had failed. The engines installed in the aircraft were the General Electric Aircraft Engines (GEAE) CF6-50A model turbofan engines.

Initially, the aircraft seemed to decelerate effectively and the crew believed that it was under control and could be guided safely onto taxiway "Z," the last taxiway at the end of runway 13R, without departing the end of the runway. However, during the turn onto the taxiway, the aircraft left the paved surface before stopping on the shoulder of the taxiway. The crew estimated the aircraft was traveling at approximately 40 knots during the turn onto the taxiway. As the aircraft turned onto taxiway "Z," the right main gear failed, which resulted in the wing hitting the ground, and failure of the right wing rear spar. The spar failure resulted in a failure of the number 3 wing fuel tank, allowing massive fuel leakage to occur. Additionally, when the right wing contacted the ground, the number 3 engine also impacted the ground and was displaced inboard and penetrated the lower wing skin in the area of number 2 wing tank, allowing additional spillage of fuel. The aircraft came to a stop approximately 135 feet from the runway centerline.

After the aircraft stopped, the flight crew pulled the fire handles for numbers 1 and 2 engines and closed the engine fuel shutoff levers. The public address microphone had become displaced during the stopping sequence, and an evacuation order could not be given. The first officer opened the right front cockpit window and saw a fire on the right wing. At the same time another crewmember opened the cockpit door and black smoke could be seen in the cabin. The cabin passengers were in the process of emergency evacuation by slides.

Photo of the accident airplane on fire
Photo of the accident airplane on fire

The aircraft was consumed by fire. There were no fatalities from this accident. Twenty-seven of the 128 passengers received minor injuries, and six of the eleven crew members received minor or serious injuries, all resulting from the emergency evacuation of the aircraft. The National Transportation Safety Board (NTSB) stated in the ONA Aircraft Accident Report that the rapid and successful egress of all occupants was partially attributed to the fact that nearly all passengers were trained crewmembers and airline employees with knowledge of the aircraft, evacuation procedures, and facilities. The report goes on to state that serious evacuation problems could have been experienced had this been a routine passenger flight with untrained airline passengers.

Photo of aircraft wreckage
Photo of aircraft wreckage

Aircraft wreckage was scattered over an area 1,086 feet wide and 8,460 feet long, the majority being to the right of the runway centerline. Twenty-three Greater Black-backed and Herring Gull carcasses were found scattered across the runway between 6,400 feet and 7,100 feet from the point of break release. One recovered carcass had a wingspan of 66 inches. The largest bird weighed five pounds, and the average weight of the birds was 3 - 4 pounds. Debris from the number 3 engine that was found on the runway included the lower high pressure compressor (HPC) case, the HPC stage 1 and 2 disks, the complete fan module, and miscellaneous parts that included the fuel feed line. A three-foot section of the fan midshaft was located to the right of the runway. The HPC rotor assembly stages 3 through 13 came to rest approximately 900 feet to the left of the runway centerline and caused damage and fire to a Pan American World Airways service shed. The stage 14 HPC disk was not recovered from the accident site.

Photo of wreckage
Photo of wreckage

A detailed disassembly and examination of the number 3 engine occurred at the engine manufacturer as part of the accident investigation process. The NTSB and GEAE ultimately reached different conclusions relative to the precise engine failure sequence and cause of the catastrophic failure of the engine. Examination of the engine hardware indicated this had been a massive uncontained engine failure. Forces associated with the engine failure caused liberation of the inlet cowl, fan cowl, the core cowl, and the thrust reverser. The upper and lower HPC case assemblies had separated from the engine at the circumferential flanges and horizontal split lines.

Examination of the number 3 engine also showed evidence of at least six bird strikes on the lip assembly of the engine inlet cowl. Bird feathers and debris were found on fan blades, the fan spinner, and other parts of the engine. View the Fan Rotor Assembly Diagram

An examination of the fan module revealed two fan blades that had outer portions broken off approximately four inches below the midspan shroud. All fan blades had pieces broken off at leading edges, with varying degrees of panel to tip, and leading edge damage. GEAE and NTSB did not agree on the type of foreign object(s) that initially caused the impact damage to the fan blades.

Photos of fan blade damage survey showing bird matter
Photos of fan blade damage survey showing bird matter

Great Black-Backed and Herring Gulls

Photo of Great Black-backed Gull
Great Black-backed Gull

Photo of a Herring Gull
Photo of Herring Gull

The Black-Backed Gull is the largest of the gulls. It may weigh between 3 and 4 lbs and its wing span can reach 63 inches. It can be identified by its pure white underparts and sooty black wings and back. It is primarily found on the coastal Northeastern part of the U.S. Over the past 100 years, its population has been increasing and expanding southward.
The Herring Gull, is also a large gull (up to 26 inches long, with a wingspan of 54 to 59 inches), and is the best known, or most common of all gulls in North America. Some Herring Gulls, especially those in colder climates, migrate south in winter, but those along the lower Great Lakes, and on the east coast of the United States tend to be permanent residents. They are common around garbage dumps, and have adapted well to urban life.

It has been noted that gulls are attracted to the ease of finding food at garbage dumps. The proximity of many airports to garbage dumps, in addition to the open spaces at airports, makes it an ideal environment for gulls to congregate. Gulls are slow fliers, so if they loiter at an airport, it increases the probability of collisions with airplanes.

Gulls are also social in nature, and tend to congregate in large flocks. Large concentrations of flocking gulls, such as those involved in this accident, represent one of the greatest hazards to aviation. The gulls in this accident were initially standing on the runway, rather than vertically distributed in flight. This represents the most dense threat for a flock encounter, as they are tightly arranged and occupy the same two-dimensional plane (the runway). As they became airborne, in response to the approaching airplane, they remained an essentially two-dimensional, threat near the ground, through which the airplane had to transit.

NTSB Conclusions

By examining the engine hardware, interviewing the flight crew, and reviewing the available evidence, the NTSB concluded the number 3 engine had ingested multiple gulls at high power during the takeoff on runway 13R. The impact of the birds on the fan blades rotating at high rotational speeds resulted in severe damage to the fan blades and loss of fan blade material. The loss of fan blade material (loss of mass) caused a very high fan rotor imbalance of approximately 122,000 gram inches. The NTSB also concluded that the aircraft fire initially started due to debris from the uncontained engine failure fracturing the main fuel line and hot engine parts igniting the raw fuel that was released. The failed tire also made a hole in the wing skin which released fuel.

The NTSB determined the probable cause of this accident to have been the disintegration of, and subsequent fire in, the number 3 engine following ingestion of multiple gulls. Following the engine failure the aircraft failed to decelerate effectively for the following reasons:

  1. The number 3 hydraulic system was inoperative, which caused the loss of the number 2 brake system and reduced brake torque;
  2. The number 3 thrust reverser was inoperative;
  3. At least three tires were failed;
  4. The number 3 system spoiler panels on each wing could not deploy; and
  5. The runway surface was wet.

The NTSB further concluded that the flight crew performed exceptionally well executing the aborted takeoff. They completed the rejected takeoff checklist, followed procedures, and when it became apparent they were not going to get the airplane stopped on the runway, they executed a high speed turn onto the taxiway to avoid hitting a blast fence located at the end of the runway.

GEAE Conclusions

GEAE's failure investigation identified a conclusion that differed from that of the NTSB regarding the initiating event of the engine failure. They believed that debris from a failed main landing gear wheel and tire were ingested into the engine during the takeoff roll, but prior to the engine bird ingestion. GEAE concluded that fragments from the wheel caused extensive hard body impact damage and liberation of blade material that resulted in high fan rotor imbalance.

GEAE photos of wheel fragment and illustration of proximity of main landing gear wheels/tires to the No. 3 engine
Left: Photo of a piece of wheel fragment - Right: Illustration of proximity of main landing gear wheels/tires to No. 3 engine inlet.
Photos used with permission of GEAE

Wheel and Tire Failures - GEAE Conclusions

GEAE concluded the birds that were ingested into the No. 3 engine did not cause the fan blade damage, and were not a factor in the engine failure. This finding was based on their metallurgical examination of the damaged fan blades, prior service history of the CF6 engine, and previous bird ingestion events. GEAE further concluded that tire material impacted and penetrated the left side of the No. 3 engine core cowl, severing an engine fuel manifold line, resulting in a fuel explosion within the engine core compartment.

GEAE photos of Wheel Tie-Bolt and Wheel Tire Assembly, Showing location of Tie-bolts
Left: Photo of DC-10 Wheel Tie-Bold - Right: DC-10 Wheel and Tire Assembly, showing location of Tie-Bolts.
Photos used with permission of GEAE

Overpressure and Fan Rotor Imbalance - GEAE Conclusions

One aspect of the accident investigation was an examination of the extreme overpressures that developed in the engine and the manner in which the engine failed. GEAE conducted a detailed engineering study of the dynamic loads that result from sudden changes in fan rotor balance due to blade damage. This study included full scale testing of engine structures, and five separate controlled engine tests to understand the root cause of this failure, and define the necessary corrective actions.

GEAE determined by test that a very high fan rotor vibration resulted from the high rotational speeds of the damaged and highly unbalanced fan rotor (i.e., missing fan blade material). The high unbalance caused a shift of the fan rotor center line that resulted in the rotating components of the fan rotor contacting the static, non-rotating components. The fan blade tips and booster (low pressure compressor) blade tips then rubbed very hard into the outer shroud.

Closeup view of area #19 on fan blade #21
Closeup view of area #19 on fan blade #21- showing hard body damage to fan blade, with embedded bird debris on fracture surface
- Used with permission of GEAE

During normal engine operation the clearances at the blade tips are very low, to maximize engine efficiency. But in severe unbalance conditions, such as this event, the tips of the rotating blades can rub very hard into the nonrotating outer shrouds. The shrouds are covered by a layer of abradable material. During normal engine operation, the abradable material is intended to rub off into the flow path when there are light rubs of the blade tips against the outer shroud. The No. 3 engine experienced a high unbalance due to the damaged fan rotor that resulted in hard rubs, and the release of large quantities of the pulverized abradable material into the flow path. The pulverized abradable material entered the high pressure compressor where the material was exposed to sufficiently high temperature/pressure conditions to result in the material igniting. This resulted in an overpressure within the compressor section, causing the compressor cases to separate. GEAE's conclusion was that the particular abradable material used in the engine had greater combustibility characteristics at lower operating temperatures than other types of abradable shroud material used in engines.

Photo of Tie-bolt Thread Imprint on Fan Blade
Photo of Tie-bolt Thread Imprint on Fan Blade
- Used with permission of GEAE

The NTSB concluded the material ignited explosively and overpressurized the compressor case sections resulting in the case separations and loss of structural integrity of the engine. GEAE's investigation concluded that the pulverized material had ignited in the compressor and partially separated the compressor cases but not with sufficient explosive force to result in loss of structural integrity to the engine. GEAE further concluded that tire debris penetrated the core cowl area and severed a fuel manifold line. The raw fuel in the confined core cowl area ignited and caused the explosive damage to the engine. This damage in combination with the failed compressor case sections resulted in the catastrophic failure of the engine.

Through the detailed engineering study and testing conducted by GEAE as part of the accident investigation, it was believed by GEAE that the pulverized abradable shroud material ignited in the HPC and overpressurized the compressor case. As a result, GEAE identified an alternate abradable material that was shown by a controlled engine test to have acceptable characteristics and not ignite in the compressor section. The alternate material was incorporated into all CF6 production engines, and the FAA issued two Airworthiness Directives mandating the replacement of the old abradable material with the new material for all CF6-6 and CF6-50 series engines that were in revenue service.

View the animation illustrating the engine failure scenarios developed by both the NTSB and GEAE.

Bird Ingestion and Airport Bird Control 

The NTSB issued several safety recommendations highlighting the problems and deficiencies related to airport bird control and the potential hazards of aircraft bird strikes. John F. Kennedy International Airport is located on Jamaica Bay, which had numerous mud and sand flats, swampy islands, and garbage dumps. An area of the airport was also adjacent to a wildlife refuge. There was an established bird control program at JFK Airport to address a recognized bird hazard problem, and at the time of the ONA accident, the FAA was monitoring the program and working with the airport authorities to implement a more aggressive bird hazard reduction program.

Photo of JFK staff attaching metal leg bands to Canada geese
Photo of Staff attaching metal leg bands to Canada geese in a park near the JFK airport as part of a local Canada goose movement study. Satellite transmitters were attached to 10 of these geese the following year to get even more data on where they move and how far they move on a daily basis in this urbanized area.

Photo of Airport Wildlife Supervisor relocating a diamondback terrapin turtle.
Photo of Airport Wildlife Supervisor relocating a diamondback terrapin turtle.

Photo of Interactive training program for airport operations and other staff.
Photo of Interactive training program for airport operations and other staff.

The most frequent aircraft/bird encounters have historically occurred during flight operations in or around airports and near the ground. Successfully mitigating the hazards of the bird threat to aircraft incorporates multiple approaches including:

  • An aggressive and effective airport bird control program that will reduce the
    number of birds in and around the airport areas;
  • Flight crew educational training, awareness, and avoidance procedures related
    to bird threats, and;
  • Engine and aircraft designs capable of sustaining substantial bird strike encounters.

Following the ONA accident the FAA formed a special task force to visit certain airports and obtain information and data on airport bird hazards that were used in developing a national program of bird hazard reporting and alleviation. The FAA also issued a General Notice that was transmitted to all FAA regions to implement a 60-day special emphasis program designed to identify airports having bird problems and to initiate action directed at alleviating the hazards at these airports.

Current Wildlife Management Strategies at JFK

Currently, the Port Authority of NY/NJ takes a multi-tiered approach to wildlife mitigation. This includes habitat modification, wildlife dispersal, daily wildlife patrols, bird monitoring, laughing gull nest surveys, mammal spotlight surveys, insect control, water management, egg-oiling, trapping, and shooting when necessary. Outside agencies have been called for action, when necessary, to help manage the bird population in the vicinity around the airports. The Port Authority has a staff wildlife biologist who assists the Wildlife Supervisors. The Wildlife Supervisors provide around-the-clock airport coverage.

The Port Authority of NY/NJ supplements its internal wildlife management staff with outside contracts for wildlife control such as with USDA-Wildlife Services. Additional resources include JFK's wildlife strike database which dating back to 1979 and is one of the oldest and most comprehensive in the world. It also counts with a long standing Bird Hazard Task Force, composed of representatives of FAA, USDA-Wildlife Services, National Park Service, U.S. Fish & Wildlife Service, New York State Department of Environmental Conservation, New York City Department of Environmental Protection, and New York City Department of Parks & Recreation. This task force provides suggestions for improving wildlife management practices to reduce bird hazards.

Airports that identify a wildlife issue and its potential hazard to the airport proceed to develop a wildlife management plan. The cognizant authority requests an assessment by a wildlife biologist, who determines the threat and suggests solutions. The airport then develops a plan that address how those threats will be mitigated.

At JFK Airport, the Port Authority of New York is responsible for the bird control program via their Wildlife Management Plan. The plan manages all water, wetlands, habitat, or migratory or permanent population issues. It consists of continuous surveillance of the airport through vehicles and Wildlife Agents. Wildlife Agents regularly inspect the runways and vicinities.

Runway Sweeps at JFK - Current Practice

The Wildlife Supervisor and/or Senior Wildlife Supervisor will conduct daily runway sweeps at or around sunrise. Additional runway sweeps will be conducted by the Wildlife Supervisor or Wildlife Agent as requested by the FAA air traffic control tower (ATCT) or the Airport Duty Supervisor when runways change from inactive to active. During the morning runway sweep, the Wildlife Supervisor will search for carcasses from any unreported wildlife strikes. When a runway opens to aircraft activity from an inactive status, the Wildlife Supervisor or Wildlife Agent must conduct a "bird sweep" to disperse any birds or other wildlife in the area and verify that there are no wildlife hazards on the runway. Carriers and other airport entities are encouraged to report any wildlife problems, so that they are investigated.

Runway Sweep Patrol being performed at JFK
Runway Sweep Patrol being performed at JFK
Photo source Port Authority of New York and New Jersey – Used with permission

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