Summary
We propose to adopt a new airworthiness directive (AD) for all The Boeing Company Model 747-8 and 747-8F series airplanes. This proposed 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 proposed AD would require 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 proposing this AD to detect and correct heat damage to the vapor seals between the engine strut and aft fairing. Such damage could allow flammable fluid leakage into the aft fairing, which could result in an uncontrolled fire in the engine strut.