Gulfstream Aerospace Corp. is warning pilots that a feature designed to prevent crashes is not fail-safe and that operators must rigorously follow a flight checklist before taking off. The warning comes in the wake of a May crash at Hanscom Field that killed seven people, including Philadelphia Inquirer co-owner Lewis Katz.
In a letter dated Aug. 18, the maker of business jets issued a caution about the locking system on the Gulfstream IV, the model that crashed at Hanscom. That mechanism, known as a gust lock, protects the plane from damage when it is on the ground. But the lock must be released for aircraft to get off the ground.
It remains a mystery whether the lock on Katz’s flight was on or off, but Gulfstream is “trying to make sure our operators are informed about proper procedures about the gust lock system,” said company spokesman Steven Cass, who characterized the recently issued letter as routine. The warning applies to more than 2,000 Gulfstream aircraft.
When the gust lock is on, flight controls known as ailerons and rudders remain in a neutral position, and the elevators are in a down position. The elevators, located on the rear wings of the plane, are crucial to lifting the plane’s nose to take flight.
In theory, if the lock is in place, the jet should be able to muster only 6 percent of its total power, preventing takeoff. But Gulfstream says that in some instances, the jet may be able to attain enough power for liftoff — even though the flight controls remain in the wrong position, creating a potentially dangerous scenario.
Gulfstream’s letter says flight crews must make sure the gust lock is disengaged before starting the engine and then independently verify that the flight controls can move freely before taxiing.
“The freedom of flight-control movement is the ultimate indicator the gust lock is fully released for all Gulfstream models,” Mitchell A. Choquette, Gulfstream’s director of customer support and field service, wrote in the letter.
A spokeswoman for the Federal Aviation Administration said the agency is aware of the letter and monitoring the issue.
This is the second letter Gulfstream has issued about the gust lock and safety procedures since the crash. In June, the company urged flight crews to perform certain maintenance checks before takeoff and ensure the gust lock is released before starting the engines.
Bloomberg News was the first to report on the latest letter, which was sent to all Gulfstream operators.
Gene Allen, a Florida pilot who flies Gulfstreams, said he checks the ailerons, rudders, and elevators before heading down the runway, instead of just reviewing the status of the gust lock.
“It’s not something that I would expect to rely or use as a gauge of whether [the flight control] was working properly or not,” Allen said. “It wouldn’t occur to me that I was protected in that way.”
Aviation experts said it is unlikely that major fixes on the jets would be required, given the potential cost and the ability for flight crews to avoid the problem.
The chief executive of Private Jet Services, an aviation consultancy company in Seabrook, N.H., said that if Gulfstream attempted to mandate such fixes, the company would probably face opposition from jet owners.
‘When you start the engines, you pressurize the hydraulics system, which makes it more difficult to disengage the lock.’
“I’m confident the various operators who would bear the expense of these modifications will have a great deal to say to Gulfstream” before such a requirement became final, said Greg Raiff, the Private Jet Services executive.
The jet carrying Katz reached a speed of nearly 190 miles per hour on the runway, but never became airborne. Rather, the jet left the runway, rolled onto the grass, struck an antenna, and burst through a chain-link fence before sliding into a gully, where it erupted into flames.
Katz, three guests, and a three-member crew were departing Hanscom Field in Bedford on May 31 when their Gulfstream IV crashed.
Katz had flown to Massachusetts to attend a fund-raiser at the Concord home of historian and author Doris Kearns Goodwin and her husband, former presidential adviser Richard Goodwin.
FAA records show that the plane was owned by SK Travel LLC, a North Carolina company managed by Katz and Emil W. Solimine.
Solimine was out of the country and unavailable for comment Tuesday, an assistant said.
Ed Stier, a New Jersey attorney representing Katz’s family, said they had no comment.
Pilot James McDowell, 61, of Georgetown, Del., and copilot Bauke “Michael” De Vries, 45, of Marlton, N.J., were also killed. Their families did not respond to a request for comment.
While the question of whether the plane’s gust lock was engaged remains a mystery, investigators found clues that could prove telling.
The position of the elevators at the back of the plane was consistent with the gust lock being on, according to information from the flight data recorder. If the elevators were in the down position, the plane would not take off.
But authorities going through the jet’s wreckage discovered evidence suggesting the lock was released, a June report from the National Transportation Safety Board said.
Bruce Landsberg, president of the Aircraft Owners and Pilots Association Foundation in Frederick, Md., said pilots should turn off the engine if they find the gust lock engaged after starting the aircraft.
“When you start the engines, you pressurize the hydraulics system, which makes it more difficult to disengage the lock,” he said.
Raiff, of Private Jet Services, said the Gulfstream memo is a reminder of “how important it is to adhere to the strict safety and operating procedures for aircraft.”
“I sort of read it as a disclaimer and admonition to its fleet operators to not take short cuts and follow the gosh darn manual,” he said.