EASA SIB NM-16-24
Learjet 25, 28, 29, 31, 35, 36, and 55 Fuselage Main Plate/Skin
Summary
The Special Airworthiness Information Bulletin SAIB: NM-16-24 is an FAA information bulletin addressing potential skin corrosion under the external oxygen line fairing on the top aft fuselage of Learjet models 25, 28, 29, 31, 35, 36, and 55. This bulletin informs owners and operators about the corrosion risk but does not mandate corrective action through an airworthiness directive. It covers multiple Learjet variants including 25A, 25B, 25C, 25D, 25F, 31A, 35A (C-21A), 36A, 55B, and 55C.
What Changed
This bulletin introduces awareness of potential fuselage skin corrosion beneath the oxygen line fairing on affected Learjet models. It recommends inspections per specific Learjet service bulletins but does not impose mandatory regulatory requirements or airworthiness directives. The bulletin consolidates inspection guidance and reporting recommendations for affected aircraft.
Why It Matters
This information is important for aviation professionals because undetected corrosion can compromise fuselage structural integrity and safety. Operators and maintenance teams need to be aware of this potential issue to ensure timely inspections and repairs, thereby maintaining aircraft airworthiness and preventing more extensive damage. Reporting inspection results helps Learjet monitor the corrosion issue and improve safety measures.
What To Do
Owners and operators of affected Learjet models should perform inspections of the upper fuselage skin under the aft oxygen line fairing following the applicable Learjet service bulletins listed in the bulletin. They should report inspection results to Learjet, even if no corrosion is found, and notify Learjet Customer Support if skin thickness falls below minimum limits. No specific compliance deadlines are mandated, but timely inspections are recommended.