Gulfstream has released Aircraft Service Change (ASC) 134 for the G650/650ER that modifies the rudder trailing edge contour to prevent an aircraft yawing condition in the event of rudder control failure. Once completed, this modification eliminates a speed restriction for the twinjet “to remain at or below 250 KCAS/Mach 0.925, which is typically not an impact in cruise flight.” The limit came per a maintenance and operations letter issued by Gulfstream last month, following an October 24 rudder control failure incident that resulted in yawing motion not previously “seen on in-service G650 aircraft and did not take place during flight testing."

According to Gulfstream, ASC 134 incorporates a rudder trailing edge wedge installation to adjust the rudder hinge moment characteristics in sideslip to avoid adverse aircraft response in the event of a rudder control failure. To ensure fleet compliance with the ASC, Gulfstream will release a Customer Bulletin to require installing the wedge within 12 months.

A Gulfstream spokeswoman told AIN that all required parts inventory has been procured and is readily available to support installation. “There are more than 50 dedicated teams across 16 Gulfstream and Jet Aviation facilities approved to perform the installation; this total includes Field and Airborne Service (FAST) teams to perform work, or required training, at additional locations if/as necessary,” she added.