The National Transportation Safety Board (NTSB) has concluded that Gulfstream’s rush to complete an aggressive flight-test schedule for its new G650 was a key factor in the April 2, 2011, crash of a test aircraft at the Roswell International Air Center in New Mexico.

In an October 10 public hearing the Board concluded that Gulfstream had made the following errors during the flight test process: failure to properly develop and validate takeoff speeds; failure to recognize and correct errors in the takeoff safety speed manifested during previous G650 flight tests; the flight test team’s persistent and aggressive attempts to achieve a takeoff speed that was erroneously low; and inadequate investigation of uncommanded roll events that occurred during previous flight tests, “which should have revealed incorrect assumptions about the airplane’s stall angle of attack in ground effect.”

NTSB chairman Deborah Hersman commented, “Deadlines are essential motivators, but safety must always trump schedule. Flight testing should not be rushed or compromised.”

The G650 crashed during a daylight simulated single-engine takeoff from Roswell when it experienced a right wing stall, causing the airplane to roll with the right wingtip contacting the runway, hitting a concrete structure and an airport weather station, resulting in extensive structural damage and a post-crash fire.

The two pilots and two flight engineers on board were killed. Although the aircraft was substantially damaged, the NTSB said the impact of thte crash was survivable but the fire was not. Hersman credited the video recorders installed in the 650’s cockpit for determining what happened during the takeoff.

“Safety is Gulfstream’s first priority,” said the airframer in a statement. “Since this accident, we have redoubled our efforts to strengthen the safety culture in flight test and throughout the rest of the company. We are committed to continuous safety improvement.”