Gulfstream G200 (IAI 1126 Galaxy)
Maintenance Airframe
Training / Qualification; Communication Breakdown; Confusion; Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Other / Unknown
General Maintenance Action
Manuals; Procedure; Human Factors; Chart Or Publication; Aircraft
I was notified by a Maintenance Control individual that the following issue had occurred and what was found on a G200 aircraft. Maintenance integration. Horizontal Stabilizer (Stab) #2 Trim Motor Inoperative. While in flight; heard Trim Aural Alert constantly going off as Stab Trim was in motion but indicator did not move. Then AUTOPILOT MACH TRIM FAIL CAS message came on. Turned off autopilot and hand flew. When on ground; isolated problem by pulling both [Circuit] Breakers (C/B) and resetting one and testing trim. Found with # 2 Breaker 'In'; trim did not move. Technicians found the Left-Hand (L/H) Lower Wiper panel installed incorrectly. I grabbed a Technician that was familiar with the work on G200 tails [Stabs] and asked him if he had known of any issues with the wiper panels on the G200 being installed wrong and he stated he wasn't sure how they could be installed wrong. After looking at an aircraft not seeing anything obvious I waited to see if I heard anything on it. Three days later; while working another G200 aircraft; I was removing the Lower wiper on the left side and another Technician was on the right side to Facilitate Maintenance (F.O.M.). After getting my side off; the other Technician told me he was removing more panels to get his off. It was then we discovered how the panels could be put on wrong. The Aft panel spans top; bottom and around the aft side of the Vertical [Stab] where the elevator goes through. On the top side there is a screw hole in which a screw needs [to be] put in which makes sure the panel is installed before the Upper Forward panel. On the bottom; there is no such fastener or hole to make the Technician installing aware. The only thing that might ring a bell is the fact that the air load moving over the panels could lift that aft panel. After discovering the issue I presented to my General Manager and he put out a memo to notify the Technicians that incorrect installation could happen.
An Aircraft Maintenance Technician (AMT) was informed the Horizontal Stabilizer (H/S) #2 Trim Motor on a G200 (Galaxy) aircraft became inoperative in flight with the Aural Alert constantly going off as trim was in motion; but Indicator did not move. AUTOPILOT MACH TRIM FAIL message appeared. Vertical Stab left Aft Lower Wiper panel installed incorrectly.