Boeing 707-321 accident at Jamaica, New York, 13 Aug 1972

Accident narrative

On August 13, 1972, at 0050 eastern daylight time, Jugoslovenski Aerotransport (JAT) Flight 3410, a Boeing 707-321, ran off the end of Runway 13R during a rejected takeoff at John F. Kennedy International Airport in Jamaica, New York. The aircraft struck a blast fence and caught fire. There were 175 passengers and a crew of 11 aboard. Fifteen passengers and one steward were injured during the evacuation.

### The flight

The charter flight was scheduled from New York to Rijeka, Yugoslavia. Because the dispatch computer used by the contracted dispatcher did not include Rijeka, the flight was dispatched to Shannon, Ireland, with the crew intending to refile their flight plan in the air.

Before departure, the crew increased the fuel load, bringing the calculated gross weight to 311,725 pounds, just under the aircraft's maximum structural limit of 312,000 pounds. The flight engineer calculated the critical engine failure speed (V1) as 150 knots.

### The takeoff and evacuation

The flight was cleared for takeoff on the 14,572-foot Runway 13R at 0049:05. As the aircraft accelerated, the cocaptain called 80 knots, followed 25 seconds later by the V1 call. Three seconds after the V1 call, at an airspeed of 154 knots, the right cockpit sliding window opened, creating a loud noise that sounded like an explosion.

The captain immediately initiated rejected takeoff procedures. He deployed the speed brakes, selected reverse thrust, applied maximum engine power in reverse, and applied the main wheel brakes. The aircraft left tire skid marks for about the last 1.2 miles of the runway. Near the end, the marks arced to the right. The Boeing 707 ran off the paved surface, continued through a steel blast fence, and stopped 120 feet past the runway end. The left outboard wing section and engines Nos. 1 and 2 were damaged by the impact and an ensuing fire.

Passengers and crew evacuated using emergency slides and the cockpit escape rope. Unsecured catering supplies, including meal boxes and ice buckets, had been propelled into the aisles during the deceleration, which passengers reported impeded their exit. The right aft galley slide failed to inflate initially, forcing some occupants to jump approximately 8 feet to the ground. Airport emergency equipment arrived in about four minutes and extinguished the fire.

### What the investigation found

The National Transportation Safety Board investigated the window opening and the aircraft's braking performance.

Investigators found that the locking mechanism on the cocaptain's sliding window was out of adjustment. The trigger hung in a midposition, and the locking pin only partially engaged the receptacle. The Board concluded that the roughness of Runway 13R could have caused the airframe to flex during acceleration, which could have been sufficient to disengage the lock completely and allow outside air pressure to force the window open. A fractured pencil found in the window track was tested and ruled out as a factor.

Regarding the overrun, the Board noted that the captain's decision to reject the takeoff was reasonable, as a pilot usually has no immediate way to assess whether a loud explosion-like sound has rendered the aircraft uncontrollable. The Board found that with all eight brakes operating, the aircraft could have stopped 2,500 feet short of the runway end, even from the 154-knot speed.

However, the investigation revealed that the aircraft had a malfunctioning V-3 relay in the left antiskid control shield. This defect prevented the relay from energizing, which kept the No. 1 front and rear brakes in a released condition at speeds above 20 knots. Consequently, the aircraft only had six operating brakes during the high-speed rejected takeoff.

The Board determined that the total energy required to stop the airplane was 39.3 million foot-pounds for each of the six working brakes, which exceeded their demonstrated capability of 38.7 million foot-pounds. This overloading resulted in excessive heat and the destruction of the six brakes before the aircraft came to a stop.

The Board noted that the malfunctioning V-3 relay had existed for a considerable period, as evidenced by the high number of landings (559 and 913) accumulated on the No. 1 brakes. There was no maintenance requirement for a routine check of the entire brake and antiskid system that would have detected the malfunction, and the crew had no indication of the reduced braking capability before the takeoff roll.

### Probable cause

The National Transportation Safety Board determined that the probable cause of this accident was "the unknown degraded capability of the heavily loaded aircraft's braking system, which precluded stopping the aircraft within the runway distance available." The Board found that this reduced capability resulted from the malfunctioning V-3 relay, which rendered two of the eight-wheel brakes ineffective. The Board concluded that "a sound like that of an explosion in the cockpit during the takeoff roll caused the captain to reject the takeoff."