(Updates with pilots starting in seventh paragraph.)
Aug. 20 (Bloomberg) -- Gulfstream jet pilots received notice from the company that a safety device designed to prevent accidents like the one that killed sports-franchise mogul Lewis Katz can be foiled in some circumstances.
The system is supposed to keep pilots from setting engines for takeoff power if control panels on the wings and tail are locked, Gulfstream told operators in an Aug. 18 letter obtained by Bloomberg News. Instead, it may be possible to add thrust “if proper unlock procedures are not followed,” it said.
The letter helps explain why Katz’s Gulfstream IV reached a speed of 190 miles (306 kilometers) an hour on the ground without lifting off as it tried to depart Bedford, Massachusetts, on May 31. It’s too early to determine if Gulfstream needs to modify its planes or pilots’ preflight procedures, said Steve Cass, a company spokesman.
“We’ll need to continue to get input and once we have sufficient input then we’ll decide if there’s any type of change that we need to make either to our procedures or to the aircraft itself,” Cass said by telephone. “I think it’s premature to make that conclusion right now.”
Gulfstream, a General Dynamics Corp. unit, has more than 2,000 aircraft in operation and all the company’s models have the gust-lock except for the G650, which uses different technology, he said.
Pilots are supposed to lock control panels on the wings and tail of the airplane when it’s parked at an airport to eliminate the risk of wind damage. Gulfstream’s flight manual requires pilots to switch off the gust-lock before starting the engines.
Four corporate pilots who have flown the Gulfstream IV said in interviews that they had all made the mistake of forgetting to switch off the gust-lock before starting the engines. They asked not to be identified because their employers don’t permit them to be interviewed.
While such an error wasn’t common, it was easy to forget to switch off the gust-lock in the proper sequence during the busy process of readying a plane for flight, they said.
When flight controls are held in position by the gust-lock mechanism, the nose of the airplane is forced down and liftoff is prevented even after the plane accelerates.
In the Katz crash, there was no evidence the cockpit crew attempted to check whether the control surfaces were working after starting the engines and taxiing to the runway, according to the U.S. National Transportation Safety Board’s review of the crash-proof flight data recorder.
Katz’s jet rolled down the 7,011-foot (2,136-meter) runway before sliding into a field, where it slammed into a gully and burst into flames. Katz and six others died.
The NTSB isn’t commenting on the accident beyond its previous statements and updates, Keith Holloway, a spokesman, said yesterday.
The Gulfstream notice reminded pilots to ensure they have switched off the gust-lock before starting the engines and to always check the flight controls before takeoff. The notice didn’t specifically reference the Katz crash.
The four pilots interviewed said that once the engines start driving the plane’s hydraulic system, which in turn moves the plane’s flight controls, it becomes difficult to release the gust-lock. It’s still possible to force the locking mechanism’s switch into the off position, they said.
If the gust-lock lever is in the on position, it limits engine power to slightly above idle, according to the plane’s manual.
None of the pilots said they knew it was possible to move the switch in a way that allowed takeoff power while retaining the lock on the flight control panels on the wing and tail. Gulfstream’s manuals don’t mention this scenario.
If pilots forget to switch off the gust-lock, Gulfstream’s flight manual advises shutting the engines down before releasing it, a time-consuming process.
In the Katz crash, the plane’s elevator, which raises and lowers the nose, was in a position “consistent” with being locked during the takeoff attempt, according to a preliminary report released June 13 by the NTSB.
The gust-lock lever was found in the off position in the wreckage, the NTSB said.
Gulfstream’s preflight procedures include several steps designed to prevent inadvertent gust-lock errors. In addition to guidance about how to turn the lock on and off, pilots are required to test the control surfaces each time they start the plane. Gulfstream also recommends pilots test the elevator again while accelerating on the runway.
The letter “is really to remind folks about that,” Cass said.
Katz, 72, had flown to Bedford to attend an event at the Concord, Massachusetts, home of Richard Goodwin and historian Doris Kearns Goodwin. Katz was a lawyer and businessman who once owned the New Jersey Nets basketball team, New Jersey Devils hockey team and ran a billboard company and parking-lot operator. He won control of the Philadelphia Inquirer newspaper and its sister publication at a court-ordered auction four days before the crash.
The other passengers were Susan Asbell, 67, of Cherry Hill, New Jersey; Marcella Dalsey, 59, of Williamstown, New Jersey, and Anne Leeds of Longport, New Jersey. A flight attendant, Teresa Ann Benhoff, 48, of Easton, Maryland, was also aboard.
The business jet was being flown by Captain James McDowell, 51, of Georgetown, Delaware, and co-pilot Michael De Vries, 45, of Marlton, New Jersey, according to the Middlesex County district attorney’s office.
Both pilots had more than 10,000 hours of flight experience, according to the NTSB.