Investigation continues into G650 crash

 - May 2, 2011, 5:50 AM

The investigation continues into last month’s fatal crash of a Gulfstream G650 during a test flight at Roswell, N.M., and it may be more than a year before the cause of the accident is determined, according to the NTSB. Tom Latson, the NTSB investigator in charge of the accident, told AIN the Board will be conducting “a thorough investigation” and confirmed that the aircraft was equipped with a telemetry data downlink. That could potentially provide the investigators with a trove of additional clues, beyond those from the twinjet’s CVR and FDR. Aside from Gulfstream, other parties to the investigation include the FAA, Parker Aerospace (manufacturer of the aircraft’s fly-by-wire flight control system) Rolls-Royce Engines and the German Accident Investigation Bureau (as the 16,100-pound-thrust BR725A1-12 engines on the aircraft were manufactured in Germany).

In its preliminary report released four days after the April 2 crash, the NTSB said the aircraft was performing a takeoff with a simulated engine failure to determine takeoff distance requirements at minimum flap setting. The G650, S/N 6002, registered as N652GD took off at approximately 9:30 a.m. from the main Runway 21 at Roswell International Air Center Airport in Roswell, N.M. in clear weather with a 15-knotcrosswind from the left.

“Immediately after takeoff, the right wing struck the ground,” said FAA spokesman Lynn Lunsford, adding that the landing gear collapsed after the jet hit the ground. The first wingtip scrape marks were found approximately 5,300 feet from the start of of the 13,000-foot runway, between Taxiways Delta and Echo. According to witnesses, the aircraft slid across the ground, issuing sparks and smoke, and caught fire while it was still moving, leaving scorched grass in its wake.

During its slide of nearly 4,000 feet, the jet struck several taxiway signs and lights as it crossed Taxiway Bravo and narrowly missed a line of out-of-service jetliners parked on the airport’s disused Runway 30. It then crossed the tower access road before coming to rest approximately 230 feet from the base of the control tower, noted Brian Powell, a division chief at the airport’s rescue and firefighting department. “It was just a fireball going toward the tower,” said Powell.

It took the airport fire and rescue crew more than 15 minutes to extinguish the blaze, which destroyed the aircraft’s fuselage. Killed in the crash were test pilots Kent Crenshaw and Vivan Ragusa and technical specialists David McCollum and Reece Ollenburg.

Flight Tests Delayed

Immediately after the accident, Gulfstream suspended flight-testing its remaining four G650s. “We are participating fully in the aircraft investigation, and will resume flying only when we and the FAA are satisfied it is safe to do so,” said Pres Henne, the Savannah-based airframer’s senior vice president of programs, engineering and test.

Jay Johnson, chairman and CEO of parent company General Dynamics, issued a statement expressing sympathy for the families of the crew, along with his faith in the program. “I am confident that as Gulfstream assists aviation authorities in the accident investigation, the cause of this terrible tragedy will be determined. We look forward to continuing the rigorous testing required to achieve flight certification of the aircraft.”The G650 program represents higher stakes for Gulfstream than usual, as the new flagship will be certified under an all-new type certificate. The last time the airframer (then Grumman) tackled an all-new certification program was for the GII in 1965; every Gulfstream large-cabin jet since has been certified as an amendment of the GII approval. At the time of the accident, the company had completed 1,500 hours of the 2,200-hour certification program, although Gulfstream declined to provide details regarding which tests remained on the program’s checklist. The company said that all other certification and production work related to the G650 is continuing, but it has not issued any statements regarding possible delays to the aircraft’s certification, which was anticipated to occur later this year in time for deliveries to begin next year.

S/N 6002 first flew in February last year and was the second of five G650s being used for certification testing. According to the company, S/N 6002 was being used to evaluate the aircraft’s systems as well as its takeoff and landing performance. As part of the certification process, Part 25 business jets such as the G650 must demonstrate velocity minimum unstick (Vmu), the calibrated airspeed at and above which the airplane can safely lift off the ground and continue the takeoff. According to FAA regulations, “Vmu speeds must be selected by the applicant throughout the range of thrust-to-weight ratios to be certificated. These speeds may be established from free air data if these data are verified by ground takeoff tests.”