Date: 201407
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: Gulfstream G200 (IAI 1126 Galaxy)
Operator: Fractional
Operating under: Part 135
Mission: Passenger
Flight phase: Parked
Aircraft component: Stabilizer Attachment
Component problem: Malfunctioning; Improperly Operated
Reporter function: Inspector
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Communication Breakdown; Confusion
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Maintenance
When detected: Routine Inspection
Result: General Maintenance Action
Contributing factors: Chart Or Publication; Human Factors; Manuals; Aircraft; Procedure
Primary problem: Manuals

Narrative: While investigating vibration; there was an effort to focus on the attaching hardware of the Vertical Stabilizer and in preparing for the replacement of the attaching hardware; discovered that there was no Call-Out for torquing sequence in the Aircraft Maintenance Manual (AMM). Upon requesting additional technical data from Gulfstream and Israel Aircraft Industries (IAI); we discovered that there was a significant disparity between the torque values listed in the AMM and what was listed on the IAI Drawings (practically double the values): 1) Our concern is that this information is not available in the AMM as required to perform adequate maintenance in this area. Flag notes and important info is missing and places an undue burden on any Operator or Maintenance Provider. More importantly is that Gulfstream and IAI have attached a financial obligation to the Owner/ Operator to obtain this information that should be contained in the AMM. 2) The Aft Vertical Stabilizer bracket securing bolts shall be torque first. There is no specific sequence of order in tightening. General practices have all the bolts brought up to torque; as evenly as possible to prevent any binding of the fitting joint. 3) Note: the following items in the AMM are incorrect.  A) AMM 55-30-00; Figure 404; Detail F; is labeled incorrectly. Detail F is the forward fitting and Detail G is the aft fitting. The forward fitting is the only attachment that has a shim.  B) The Aft fitting bolts are torque to 1200 to 1600 lb-inches; the locking nuts are torque to 450 to 550 lb-inches.  C) The Forward fitting bolts are torque to 620 to 840 lb-inches; the locking nuts are torque to 450 to 550 lb-inches. 4) Be sure to follow the AMM procedures (except as noted above) and Illustrated Parts Catalog (IPC) requirements and be aware that one bolt stack-up is different from the rest on the Forward and Aft attach brackets. 5) For further instruction contact Technical Operations.[Recommend]:1) An investigation needs to be completed to determine if the proper torque value was applied during initial assembly of all G-200 aircraft. 2) Require Original Equipment Manufacturer (OEM) to supply all technical data in AMM for all Operators and Maintenance personnel to have access to. Maintenance Inspector. Hangar. Structural [Issue]. Aft [position].




Synopsis: An Aircraft Maintenance Inspector (AMI) reports there was significant disparity between the Torque Values listed in the Gulfstream G-200 Aircraft Maintenance Manual (AMM) for the Vertical Stabilizer attaching bolts compared to what was listed on the Israel Aircraft Industry (IAI) drawings for the same bolts; torque values were almost double.