EASA AD US-2017-26-05
Wings - Flap Track - Replacement
Summary
Federal Aviation Administration Airworthiness Directive 2017-26-05 is a final rule addressing certain Gulfstream Aerospace Corporation Models G-1159A (GIII), G-IV, and GIV-X (G450) airplanes. It mandates the replacement of flap track C parts that were found to have an upper flange thickness less than the design minimum. This directive aims to ensure continued airworthiness and safety of the affected aircraft models.
What Changed
This new airworthiness directive requires operators to replace any defective flap track C on the left and/or right side of the affected Gulfstream models. It introduces a compliance requirement to replace these parts within six months of the effective date. The directive also clarifies that reporting to the manufacturer is not mandatory under this AD.
Why It Matters
This AD is critical for aviation professionals because defective flap tracks can lead to flap actuator failure, flap twisting, or asymmetrical flap failure, potentially causing an unrecoverable roll. Operators and maintenance organizations must address this unsafe condition promptly to maintain aircraft safety and regulatory compliance. Failure to comply could result in serious flight safety risks and regulatory penalties.
What To Do
Affected operators must replace the flap track C parts, part numbers 1159WM20052-105 (left side) and/or 1159WM20052-106 (right side), with airworthy parts within six months after January 25, 2018. Replacement procedures are detailed in Gulfstream III Customer Bulletin Number 187, Gulfstream G450 Customer Bulletin Number 195, or Gulfstream IV Customer Bulletin Number 240, all dated June 28, 2017. Special flight permits are allowed with limitations until compliance is achieved.
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