Gulfstream plans to fly a G500 with the US Federal Aviation Administration (FAA) this week as part of efforts to lift landing restrictions on that jet and its G600 sibling resulting from two hard landings.
Mark Burns, president of the Savannah-based aircraft maker, expects the FAA to lift those restrictions, which prohibit landings in calm winds, in September.
Gulfstream is working on rolling out a software update that fixes the problem, and the FAA has moved some of the G700 certification staff to validate the software change, Burns added, speaking at the Farnborough Airshow on Tuesday. July 19.
“We have reached the point where we will start flying with the FAA this week to validate the software,” he says. “Our timeline is to lift the restrictions in September…I think we’re still on track to do that.”
FlightGlobal reported in early May that Gulfstream had restricted the G500s to landing only when wind speeds do not exceed 15 knots (28 km/h). It also prohibited landings when gusts exceed 5 kt. Gulfstream has published the provisions in Flight Manual Updates.
A few days later, the FAA formalized restrictions in the Airworthiness Directives (ADs) that applied to the G500 and G600 – some 120 US-registered jets in total. The pair share similar flight control systems.
The moves were in response to hard landings in February 2020 and April 2022.
Both incidents involved erroneous activation of the jets’ angle of attack (AoA) “limiter” feature (also called an alpha limiter), which is designed to prevent stalls.
The systems activated due to “rapid, large, and oscillating pilot control inputs near approach reference speeds, induced by unstable atmospheric conditions and gusty winds,” the FAA said.
This led to the AoA limiter replacing “pilot control input”, the regulator said.
Gulfstream claims that its software patch will prevent such issues.
Burns says the FAA “has moved some resources” from the G700 to the G500/G600 software patch, but downplays the impact of this change on the G700 certification timeline.
“We don’t think in the long run it should have a major impact,” Burns says. “The software we are working on for 500/600 – the improvement, to lift the limitations – [is] actually the same software that is on the G700.
Gulfstream has not delayed its first scheduled G700 delivery beyond a three to six month delay it disclosed in April, Burns notes. This change places the first delivery in 2023.