EASA SIB 2007-30
FAA SAIB NM-07-48 - Gulfstream G-IV series aircraft - Potentially Reduced Lug Radius Dimension on the Aileron Boost Bellcrank Clevis
Summary
FAA Special Airworthiness Information Bulletin NM-07-48 is an informational bulletin addressing a potential manufacturing issue on Gulfstream G-IV series aircraft, specifically serial numbers 1000 through 1278. The bulletin highlights a potentially reduced lug radius dimension on the aileron boost bellcrank clevis, which could affect hydraulic actuator attachment. This issue was also noted in EASA Safety Information Notice 2007-30.
What Changed
This bulletin introduces awareness of a manufacturing discrepancy involving the lug radius dimension on the aileron boost bellcrank clevis of Gulfstream G-IV series aircraft. It informs operators that the lug radius may be smaller than specified, which could lead to failure of the bellcrank lug and loss of hydraulic power to the aileron surface. Gulfstream has issued Customer Bulletin 121 recommending inspection of the affected parts.
Why It Matters
The potential failure of the aileron boost bellcrank lug could result in loss of hydraulic power to the aileron, impacting flight control. Although manual reversion control remains available, this issue poses a safety risk that operators and maintenance personnel must address to ensure continued airworthiness and safe operation of Gulfstream G-IV aircraft.
What To Do
Operators of Gulfstream G-IV series aircraft should perform a one-time inspection of the aileron boost bellcrank lug thickness and lug radius ratio as recommended in Gulfstream Customer Bulletin 121. The inspection involves measuring the lug dimensions with a vernier caliper. No mandatory compliance deadline is specified, but timely action is strongly recommended to mitigate risk.
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