What happened
On an international cargo flight traveling from Virginia to Bahrain, an Arrow Air DC-8-63, registration N441J, experienced a runway excursion at Gander. While the flight crew initially considered an approach for Runway 22, they opted for a straight-in ILS approach to Runway 04 due to a low cloud ceiling and a displaced threshold on the alternative runway.
During the final approach, the aircraft maintained a high groundspeed and a steep descent rate. The aircraft crossed the runway threshold at approximately 90 feet above the pavement with a groundspeed of 190 knots. The aircraft touched down significantly past the nominal touchdown point, approximately 2800 to 3500 feet beyond the threshold. Despite the application of reverse thrust and braking, the aircraft could not stop before the end of the runway, striking wooden barricades and coming to rest 100 feet beyond them. There were no injuries to the five people on board.
The investigation
The investigation focused on the landing performance and the accuracy of the crew's weight and balance calculations. Investigators found that the crew's calculated maximum landing weight did not account for the nine-knot tailwind present at the time of landing. While the crew calculated a maximum landing weight of 255,400 pounds, the actual weight of the aircraft was 249,500 pounds; however, once the tailwind reduction was applied, the aircraft was 22,900 pounds over the allowable limit.
Furthermore, the investigation examined the reliability of the flight data recorder (FDR). Analysis revealed that several FDR parameters were inaccurate, including erroneous airspeed readings and incorrectly wired longitudinal and vertical acceleration inputs. The investigation also noted that the crew's landing calculations used an incorrect runway length, as they failed to account for a published NOTAM regarding a displaced threshold.
Findings
- The crew failed to incorporate the nine-knot tailwind into their landing performance calculations.
- The aircraft was on an unstable approach characterized by excessive approach and touchdown speeds.
- The pilot did not execute a missed approach despite the unstable approach parameters.
- The combination of a high threshold crossing height, excessive speeds, and an extended touchdown point led to the overrun.
- Several parameters on the flight data recorder were malfunctioning or recorded incorrectly.