Airworthiness Directive · Amendment 39-18151 · Equipment/furnishings
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 747-400 and 747-400F airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 747-25A3640, dated January 8, 2014.
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 747-400 and 747-400F series airplanes. This AD was prompted by reports of cracking in the main equipment center (MEC) drip shield and exhaust plenum. This AD requires installing a fiberglass reinforcing overcoat on the MEC drip shield. We are issuing this AD to prevent water penetration into the MEC, which could result in an electrical short and potential loss of several functions essential for safe flight.
Within 24 months after the effective date of this AD, install a fiberglass reinforcing overcoat on the MEC drip shield, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-25A3640, dated January 8, 2014.
