McDonnell Douglas DC8-63 accident at Norfolk, Virginia, 25 Oct 1983 (N797FT)

Accident narrative

On October 25, 1983, Flying Tigers Flight 2468, a McDonnell Douglas DC8-63 (N797FT), overran the runway while landing at Chambers Field, Naval Air Station (NAS) Norfolk, Virginia. The airplane went off the side of the runway and slid into a swamp. None of the five occupants were injured, but the airplane was substantially damaged.

### The flight

Flight 2468 was operating as a ferry flight from John F. Kennedy International Airport (JFK), New York, to NAS Norfolk. Upon arrival, the flight was scheduled to convert to a military charter to transport cargo to Keflavik, Iceland. A flightcrew of three and two company employees were on board. The captain had 7,804 flight hours, including 6,346 hours in the DC-8. The first officer had 6,759 flight hours, and the second officer was an experienced pilot.

Before departure, the crew reviewed the dispatch package. The dispatcher had incorrectly listed runway 28 as the preferred runway and stated the maximum allowable landing weight was 275,000 pounds. Based on the forecast weather, the correct runway was runway 10, and the actual maximum landing weight was 256,304 pounds. The captain accepted the information without cross-checking it against the airport performance chart. The airplane departed JFK at 0815 with a calculated landing weight of 250,828 pounds.

### The sequence of events

Approaching Norfolk, an air traffic controller advised the flight that the weather at Chambers Field included a 600-foot overcast ceiling, 1 mile visibility, moderate rain showers, fog, and winds from 360 degrees at 20 knots.

The flight was cleared for a ground controlled approach (GCA) to runway 10, which was 8,068 feet long. At 0905:16, the final controller advised the crew to expect a heavy windshear one to two miles from touchdown, based on a previous pilot report. The captain instructed the first officer to monitor the inertial navigation system for windshear. The captain determined the reference speed was 141 knots, added 5 knots for a bug speed, and added 10 knots to compensate for the reported windshear, resulting in an approach speed of 157 knots.

During the approach, the headwind decreased. At 0908:20, the first officer announced an indicated airspeed of 154 knots and noted the headwind was five knots. At 0908:26, the controller advised the flight was at decision height and on glidepath.

The airplane crossed the runway threshold at about 50 feet. Flight data recorder information indicated the airspeed at the threshold was 151 knots, 10 knots above the reference speed. The captain reduced thrust to get below the glideslope, intending to plant the airplane firmly on the first 1,000 feet of the runway.

The airplane touched down, but skipped or floated. The captain stated the left main landing gear made contact softly and the airplane skipped back into the air. The Board concluded the final touchdown occurred between 3,100 and 3,800 feet beyond the runway threshold.

After touchdown, the ground spoilers deployed and the captain applied full wheel brakes. The brakes were ineffective. The cockpit voice recorder indicated that reverse thrust was not applied until 0908:56, seven seconds after touchdown, and engine power decreased again about ten seconds later.

As the airplane passed the 2,000-foot remaining marker, it drifted to the right side of the runway. At 0909, the airplane went off the runway, crossed an airport boundary road, went through a chain link fence, and came to rest in a swamp.

### What the investigation found

The landing gear tires were inflated and in satisfactory condition, with no flat spots indicating a maximum energy stop. Examination of the brakes and antiskid system revealed no significant pre-existing abnormalities. A failed logic wheelboard was found on the No. 1 wheel, but the Board concluded it probably failed as a result of being submerged in the swamp for 11 days after the accident.

Investigators found that large portions of runway 10 were flooded with standing water 1/2 to 3/4 inch deep. Airport management was aware that the runway tended to flood during moderate rain with strong northerly winds, but had no procedures to monitor the runway for water depth. Air traffic controllers had seen water spray from departing airplanes but did not request runway condition reports or relay any information about standing water to the flightcrew.

The Board found that the flightcrew failed to manage the airspeed during the approach. Preoccupied with the reported windshear, he did not bleed off the speed additives as the headwind decreased. The first officer failed to announce that the airspeed was excessive at the threshold. The excessive speed resulted in an extended float.

The Board concluded that the airplane encountered total dynamic hydroplaning immediately after landing due to the flooded runway and the touchdown speed. The hydroplaning significantly reduced braking effectiveness. However, the Board believed the airplane could have been stopped safely if it had touched down at the normal 1,000-foot point and if maximum reverse thrust had been applied immediately.

### Probable cause

The National Transportation Safety Board determined that the probable cause of the accident was "the flightcrew's mismanagement of the airplane's airspeed, resulting in an excessively long landing on a wet, partially flooded runway; mismanagement of thruster reversers; and hydroplaning."

The Board found that contributing to the accident was "the failure of airport management to identify, assess, and disseminate hazardous runway conditions warnings and the failure of air traffic controllers to inform the flightcrew that there was standing water on the runway."