Status:	Final
Date:	02 MAY 1980
Time:	06:34 PDT
Type:	McDonnell Douglas DC-9-81
Operator:	McDonnell Douglas
Registration:	N980DC
C/n / msn:	48000/909
First flight:	1979
Total airframe hrs:	364
Engines:	2 Pratt & Whitney JT8D-209
Crew:	Fatalities: 0 / Occupants: 7
Passengers:	Fatalities: 0 / Occupants: 0
Total:	Fatalities: 0 / Occupants: 7
Airplane damage:	Substantial
Airplane fate:	Repaired
Location:	Edwards AFB, CA (EDW) (United States of America)
Phase:	Landing (LDG)
Nature:	Test
Departure airport:	Edwards AFB, CA (EDW/KEDW), United States of America
Destination airport:	Edwards AFB, CA (EDW/KEDW), United States of America

Narrative:
The aircraft was on a certification test flight to determine the horizontal distance required to land and bring the aircraft to a full stop as required by 14 CFR 25.125 when the accident occurred. The DC-9-80 touched down about 2,298 feet beyond the runway threshold. The descent rate at touchdown exceeded the aircraft's structural limitations; the empennage separated from the aircraft and fell to the runway. The aircraft came to rest about 5,634 feet beyond the landing threshold of runway 22 and was damaged subtantially.

PROBABLE CAUSE: "The National Transportation Safety Board determines that the probable cause of this accident was the pilot's failure to stabilize the approach as prescribed by the manufacturer's flight test procedures. Contributing to the cause of the accident was the lack of a requirement in the flight test procedures for other flight crewmembers to monitor and call out the critical flight parameters. Also contributing to this accident were the flight test procedures prescribed by the manufacturer for demonstrating the aircraft's landing performance which involved vertical descent rates approaching the
design load limits of the aircraft."

Sources: