EASA AD US-2019-08-09
Nacelles / Pylons - Aft Fairing Vapour Seals / Heatshield Seals and Retainers / Block Seals / Outboard Lateral Restraint Access Panels - Replacement
Summary
The Federal Aviation Administration's Airworthiness Directive 2019-08-09 addresses all Boeing 747-8 and 747-8F series airplanes. It mandates replacement of damaged vapor seals, block seals, heatshield seals, seal retainers, and outboard lateral restraint access panels on the outboard pylons between the engine strut and aft fairing. This directive aims to prevent potential flammable fluid leaks that could lead to uncontrolled fires in the engine strut area.
What Changed
This new airworthiness directive introduces mandatory installation of new aft fairing vapor seals, heatshield seals, heatshield seal retainers, block seals, and outboard lateral restraint access panels on affected Boeing 747-8 and 747-8F airplanes. It also clarifies that operators may use maintenance records to verify part installation instead of physical inspections. Additionally, it imposes a parts installation prohibition on certain seal part numbers unless installed as specified in the Boeing Alert Service Bulletin 747-54A2247 dated August 3, 2017.
Why It Matters
This directive is critical for aviation professionals because it addresses a safety risk involving heat damage to seals that could cause flammable fluid leaks and potential fires. Operators and maintenance organizations must ensure compliance to maintain airworthiness and prevent hazardous conditions. The directive also affects parts management and installation practices, requiring careful tracking and replacement of affected components.
What To Do
Operators of Boeing 747-8 and 747-8F airplanes must inspect or review maintenance records to determine if affected parts are installed and replace them following Boeing Alert Service Bulletin 747-54A2247 within 4 years or 4,800 flight cycles from June 13, 2019. They must also comply with the parts installation prohibition for specified seal part numbers unless installed as part of the approved modification. Compliance and documentation should be maintained to meet FAA requirements.
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