Pressure to speed flight tests of a new model of General Dynamics Corp.’s Gulfstream business jet so it could win federal certification for sale was blamed by a safety agency for a crash that killed four employees.

The National Transportation Safety Board ruled this week that Gulfstream management was responsible for the accident that sent a G650, which costs $65 million and has the longest range of any private aircraft, sliding off a Roswell, New Mexico, runway in flames on April 2, 2011.

“Two prior close calls should have prompted a yellow flag, but instead of slowing down to analyze what had happened, the program continued full speed ahead,” Deborah Hersman, chairwoman of the accident-investigation agency, said at a hearing in Washington. “This crash was as much an absence of leadership as it was of lift.”

The twin-engine aircraft was approved last month by the Federal Aviation Administration after changes were made to ensure safety, the agency said in an emailed statement Wednesday. Gulfstream, based in Savannah, has 200 orders for the plane, which it calls the “flagship” of its fleet, and said it expects to begin deliveries before the end of the year.

Gulfstream has taken several steps to prevent lapses in the future, including beefing up its safety review board that oversees flight tests, according to the NTSB.

Hersman earlier this year accused Gulfstream of “obstruction” during the board’s investigation.

The company failed to quarantine accident data, lost evidence including a computer hard drive and withheld results of an internal safety audit, according to an April 4 letter from Hersman to Gulfstream President Larry Flynn.

Any failings by Gulfstream employees were inadvertent, according to a March 30 letter Flynn wrote to Hersman. He said the FBI was notified about the missing hard drive as soon as it was discovered and the employee who threw it away was fired.

“We appreciate the NTSB’s commitment to thoroughly examining this accident and determining the cause,” Flynn said yesterday after the safety board’s meeting.