McDonnell Douglas DC-10-30 accident at Jamaica, New York, 28 Feb 1984

Accident narrative

On February 28, 1984, Scandinavian Airlines System (SAS) Flight 901, a McDonnell Douglas DC-10-30, touched down about 4,700 feet beyond the threshold of the 8,400-foot runway 4R at John F. Kennedy International Airport in Jamaica, New York. The airplane could not be stopped on the runway and was steered to the right to avoid the approach light pier. It came to rest in Thurston Basin, a tidal waterway about 600 feet from the departure end of the runway. The 163 passengers and 14 crewmembers evacuated safely, with a few receiving minor injuries and one passenger hospitalized with a serious injury.

### The flight

Flight 901 was a regularly scheduled international passenger flight from Stockholm, Sweden, to New York City, with an intermediate stop at Oslo, Norway. The captain had about 18,000 flight-hours, including 2,500 in DC-10 airplanes. The first officer had about 11,000 flight-hours, with 2,500 in the DC-10.

Before leaving Oslo, the crew reviewed weather information for JFK. Because the forecast called for marginal conditions with a low ceiling, limited visibility, light rain, and fog, the captain requested additional fuel. The Atlantic crossing was routine.

### The approach and landing

Approaching the New York area, the crew received ATIS information noting a measured 300-foot overcast ceiling, 1-mile visibility in light drizzle and fog, and a potential for strong low-level wind shear. The first officer flew the approach. The crew agreed to use 35 degrees of flaps instead of 50 degrees due to the possibility of wind shear, and both autothrottles were engaged.

The systems operator calculated a landing weight of 378,400 pounds. Based on a weight of 385,000 pounds and 35 degrees of flaps, the crew obtained a calculated approach speed of 154 knots. However, the captain recalled dialing 168 knots into the autothrottle speed select window. Postaccident examination confirmed the autothrottle speed was set to 168 knots.

At about 1,000 feet radio altitude, the captain recalled seeing a tailwind component of about 20 knots displayed on the command display unit. The flightcrew stated the autopilot kept the airplane on the localizer and glideslope, and the approach was smooth.

As the airplane descended through about 800 feet, the throttles moved toward higher power and the engines increased to about 84 percent rpm. The airspeed began to increase. At about 100 feet above minimums (300 feet), the captain noted the airspeed was high and called out "speed high" to the first officer. The captain later stated he considered going around but decided to continue, influenced by his confidence in the first officer, deteriorating weather, and anticipated delays.

Over the runway, the airplane floated. The systems operator called out 50, 40, 30, and 20 feet, repeating the 20-foot callout three times. The captain then told the first officer to "put it down." The airplane touched down at 179.5 knots, about 4,700 feet beyond the threshold. None of the flightcrew could see the end of the runway at touchdown.

The captain instructed the first officer to use all three thrust reversers and full braking. The first officer stated his initial braking was light to moderate, and he increased braking as the airplane continued down the centerline. The captain also applied the brakes when he saw the end of the runway. Realizing the airplane could not be stopped on the overrun, the captain used nose wheel steering to direct the airplane to the right to avoid colliding head-on with the approach light structure. The airplane left the overrun and came to an abrupt stop with the cockpit in the water.

The captain attempted to use the public address handset and the radio to order an evacuation, but both were dead. The emergency evacuation signal was already sounding. In the cabin, the purser at the forward left door inadvertently initiated the evacuation without a command from the flightcrew. All cabin doors except two were opened, and the slide/rafts deployed. Two detached slide/rafts were used as rafts in the basin. The evacuation was completed in 60 to 90 seconds.

### What the investigation found

The airplane sustained substantial damage to the nose, lower forward fuselage, wing engines, flaps, and leading edge devices. The left wing was partially embedded in the wooden pier supporting the approach lighting system.

The Board examined the runway conditions. Although the runway was wet, there was no standing water. Friction tests showed values well above the minimum acceptable levels, and the Board concluded runway condition was not a factor.

The investigation analyzed the weather and found that the wind shear present was mild, not exceeding an average change of 3 knots per 100 feet. The Board concluded that wind shear did not adversely affect the airplane's performance and was not a factor in the accident.

The autothrottle speed control system had a history of intermittent malfunctions and had malfunctioned on the previous leg of the flight. Recorded data showed that during the descent below 800 feet, the throttles did not respond to autothrottle commands, and thrust was increased when it was not needed. However, the Board noted that pilots are expected to monitor and override such systems, and concluded that the malfunction did not directly cause the accident.

The Board found that the flightcrew intentionally added 15 knots to the approach speed to compensate for potential wind shear. The Board noted this was inappropriate for the frontal wind shear present, which was producing a decreasing tailwind. However, the Board concluded this speed additive was not a factor, as the approach could have been successful had the airspeed been controlled to the selected 168 knots.

The investigation found that the flightcrew disregarded prescribed procedures for monitoring airspeed. Required altitude and airspeed callouts were omitted during the approach. The Board noted that the crew had been conditioned by repeated successful use of the autothrottle system to rely upon its performance, leading to a lack of airspeed awareness. The airplane crossed the threshold about 60 knots faster than the calculated threshold speed and touched down 36 knots above the programmed touchdown speed.

With the touchdown occurring 4,700 feet down the runway, only about 3,700 feet remained. The Board determined this was insufficient distance to decelerate and stop the airplane. Furthermore, while the first officer selected reverse thrust on all three engines, recorded data showed the No. 2 engine did not increase past 41 percent rpm. The Board noted the lack of reverse thrust on the No. 2 engine did not appreciably add to the landing distance. Braking performance was normal, but the brake pedals were not fully depressed at the beginning of the landing roll.

### Probable cause

The National Transportation Safety Board determined that the probable cause of this accident was "the flightcrew's (a) disregard for prescribed procedures for monitoring and controlling of airspeed during the final stages of the approach, (b) decision to continue the landing rather than to execute a missed approach, and (c) overreliance on the autothrottle speed control system which had a history of recent malfunctions."