Airworthiness Directive · Amendment 39-18808 · Nacelles/pylons
The Boeing Company Airplanes
This AD applies to all The Boeing Company Model 747-8 and 747-8F series airplanes, certificated in any category.
We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 747-8 and 747-8F series airplanes. This AD was prompted by reports of damaged vapor seals, block seals, and heat shield seals on the outboard pylons between the engine strut and aft fairing. This AD requires repetitive inspections for heat damage of the vapor seals between the engine strut and aft fairing, and replacement of the seals with new seals if necessary. We are issuing this AD to address the unsafe condition on these products.
At the later of the times specified in paragraphs (g)(1) and (g)(2) of this AD: Do a detailed inspection for heat damage of the vapor seals on the outboard pylons between the strut and aft fairing of the numbers 1 and 4 engines, in accordance with Part 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-54A2246, dated February 5, 2016. Repeat the inspection thereafter at intervals not to exceed 1,200 flight cycles.
(1) Before the accumulation of 1,800 total flight cycles, or within 1,800 flight cycles after the most recent vapor seal, block seal, and heat shield seal replacement, whichever is later.
(2) Within 6 months after the effective date of this AD.
If during any inspection required by paragraph (g) of this AD any heat damage of any vapor seal is found: Before further flight, replace the vapor seal, heat shield seal, and block seal with new seals, in accordance with Part 3 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-54A2246, dated February 5, 2016. Repeat the inspection required by paragraph (g) of this AD within 1,800 flight cycles after doing the replacement, and thereafter at intervals not to exceed 1,200 flight cycles.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
