US safety investigators today criticized Gulfstream managers over charges that a chain of errors and process lapses contributed to a fatal flight test crash of a Gulfstream 650 in April 2011.

The National Transportation Safety Board (NTSB) meeting added few new details to the events leading to the crash in Roswell, New Mexico, but members instead sharpened their critique of Gulfstream's handling of time pressures and safety controls during the G650 flight test programme.

"In this investigation we saw an aggressive flight test schedule and pressure to get the aircraft certified," says Deborah Hersman, NTSB chairman. "Assumptions and errors were made, but they were neither reviewed nor re-evaluated when review data was collected."

The NTSB's findings have been a black eye to the ultra-long-range jet as Gulfstream prepares to deliver the first of 200 G650s on order by the end of the year. Although the crash made little impact on the overall schedule, the NTSB meeting makes it clear that investigators want to ensure the right controls and regulations are in place to prevent such incidents in the future.

"This crash was as much an absence of leadership as it was of lift," Hersman says.

Gulfstream issued a statement thanking the NTSB for thoroughly reviewing the accident.

"Safety is Gulfstream's first priority. Since this accident, we have redoubled our efforts to strengthen the safety culture in flight test and throughout the rest of the company," Gulfstream says. "We are committed to continuous safety improvement."

The circumstances of the G650 crash first appeared last May, as exclusively reported by Flightglobal. It was an engine-out take-off test at maximum weight, among the most challenging points on the test card.

Gulfstream had been struggling to make the G650 achieve the minimum certifiable speed after climbing 10.7m (35ft) over the runway. Programme officials tried to solve the problem partly by increasing the angle of attack at rotation, but they miscalculated the minimum angle necessary to avoid a stall. Unaware of the loss of lift at rotation, the flight crew was unable to prevent the G650's right wing from rolling off. The aircraft then veered off the runway and skidded to a stop about 100m from the airport's control tower.

Discovery is the point of any flight test, but the NTSB found that Gulfstream quickly disregarded or misinterpreted two previous wing roll-offs that could have given away the true stall angle for the G650. Gulfstream failed to reconvene a safety review board to examine the results of the previous events.

"According to industry practice, take-off tests should have stopped because these were unexpected results," says Mitchell Gallo, an NTSB air safety inspector.

Source: Flight International