The Safety Board’s full report is available at http://www.ntsb.gov/investigations/reports_aviation.html. The Aircraft Accident Report number is NTSB/AAR-12-02. On April 2, 2011, about 0934 mountain daylight time, an experimental Gulfstream Aerospace Corporation GVI (G650), N652GD, crashed during takeoff from runway 21 at Roswell International Air Center Airport, Roswell, New Mexico. The two pilots and the two flight test engineers were fatally injured, and the airplane was substantially damaged by impact forces and a postcrash fire. The airplane was registered to and operated by Gulfstream as part of its G650 flight test program. The flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed at the time of the accident.
The National Transportation Safety Board determines the probable cause(s) of this accident as follows: an aerodynamic stall and subsequent uncommanded roll during a one engine-inoperative takeoff flight test, which were the result of (1) Gulfstream’s failure to properly develop and validate takeoff speeds for the flight tests and recognize and correct the takeoff safety speed (V2) error during previous G650 flight tests, (2) the G650 flight test team’s persistent and increasingly aggressive attempts to achieve V2 speeds that were erroneously low, and (3) Gulfstream’s inadequate investigation of previous G650 uncommanded roll events, which indicated that the company’s estimated stall angle of attack while the airplane was in ground effect was too high. Contributing to the accident was Gulfstream’s failure to effectively manage the G650 flight test program by pursuing an aggressive program schedule without ensuring that the roles and responsibilities of team members had been appropriately defined and implemented, engineering processes had received sufficient technical planning and oversight, potential hazards had been fully identified, and appropriate risk controls had been implemented and were functioning as intended.
— 293 samples, 11 parameters, 09:33:50.3 to 09:34:01.3.
| Parameter | Max | at | Min | at | Final | at |
|---|---|---|---|---|---|---|
| Pitch attitude deg | 14.9 | 09:33:57.5 | -1.3 | 09:34:00.2 | 0.6 | 09:34:01.2 |
| Roll attitude deg | 30.9 | 09:33:58.5 | 1.3 | 09:34:01.0 | 1.3 | 09:34:01.0 |
| Vertical acceleration g | 2.0 | 09:34:00.7 | 0.0 | 09:33:50.3 | 0.0 | 09:34:01.3 |
222 transcribed utterances from 09:23:43.5 to 09:34:04.7, 10 sources. Final entries:
| 09:33:57.4 | HOT-2 | no no no no. *. |
| 09:33:58.5 | HOT | bank angle, bank angle [electronic voice]. |
| 09:34:00.0 | HOT-1 | ah sorry guys. |
| 09:34:02.4 | HOT | [sound similar to triple chime alarm]. |
| 09:34:04.7 | HOT-? | * * *. End of Transcript 09:34:10.3 [end of recording] |
Docket: data.ntsb.gov/Docket/?NTSBNumber=DCA11MA076. This brief is an analytical aid assembled from public records; it is not an investigative finding.