The Federal Aviation Administration on Dec. 13 issued an airworthiness directive for Gulfstream Aerospace’s top-selling G650 business jets after an unsafe condition forced one of the planes to make an emergency landing in October.
“On October 1, 2019, the FAA received a report from Gulfstream of an inflight rudder surface shutdown that resulted in lateral-directional oscillations on a Model GVI airplane,” the FAA said on Dec. 13 “The flight crew experienced an amber ‘Rudder Fail’ crew alerting system message at flight level 340 and was unable to command any movement of the rudder. The flight crew attempted a Flight Control Reset, but the condition remained. Following the rudder shutdown, the airplane experienced sustained lateral-directional oscillations, which persisted for eight minutes before the flight crew was able to stop the oscillations. The flight crew made an emergency landing of the airplane with no rudder authority.”
The FAA went on to say that, “The investigation of this inflight event revealed the root cause as an unstable rudder hinge moment when the aircraft is in a sideslip condition, combined with a rudder surface shutdown, which is inherent to the GVI aircraft type design.”