EASA SIB NM-07-39R1
Quiet Technology Aerospace (QTA) Stage 3 Hushkits, installed on Gulfstream G-1159 series aircraft
Summary
The Special Airworthiness Information Bulletin SAIB NM-07-39R1 is an FAA informational bulletin addressing issues with Quiet Technology Aerospace (QTA) Stage 3 Hushkits installed on Gulfstream G-1159 series aircraft, including G-II, G-III, and G-IIB models. It highlights the discovery of failed, cracked, or yielded forward bearing fitting attach bolts on these hushkits and provides updated service recommendations to mitigate the issue.
What Changed
This revised SAIB updates the service recommendations originally issued in SAIB NM-07-39 by specifying a replacement interval of every 400 flight cycles for the forward bearing fitting attach bolts. It endorses the use of NAS6705-48 or QTA part number G23-EJ-4024 bolts as approved replacements and advises against reinstalling the previously used NAS6205-48 bolts.
Why It Matters
The bulletin is important for aviation professionals because failure of these bolts can cause overload and binding in the hushkit ejector assembly, potentially leading to bent components. Although not deemed an unsafe condition requiring an airworthiness directive, timely bolt replacement is critical to prevent in-service failures and maintain aircraft reliability and safety.
What To Do
Operators and maintenance personnel should replace the forward bearing fitting attach bolts on QTA Stage 3 Hushkits every 400 flight cycles using the approved NAS6705-48 or QTA G23-EJ-4024 bolts. For aircraft with bolts exceeding 400 flight cycles, replacement should occur within six months to reduce failure risk. Compliance with updated Instructions for Continued Airworthiness from QTA is also recommended.
AI-generated summary from official EASA source document. Always verify against the original.