Airworthiness Directive · Amendment 39-16067 · Boeing Model 747-200C and 747-200F Series Airplanes
Boeing Model 747-200C and 747-200F Series Airplanes
This AD applies to Boeing Model 747-200C and 747-200F series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 747-25A3431, dated March 6, 2008.
We are adopting a new airworthiness directive (AD) for certain Boeing Model 747-200C and 747-200F series airplanes. This AD requires installing larger moisture shrouds and additional drain lines in the electrical/electronic equipment center. This AD results from reports of water contamination in the electrical/electronic units in the main equipment center. We are issuing this AD to prevent water contamination in the electrical/electronic units in the main equipment center, which could result in an electrical short and potential loss of several functions essential for safe flight.
Comply with this AD within the compliance times specified, unless already done.
Within 72 months after the effective date of this AD, install larger moisture shrouds and additional drain lines, by doing all the applicable actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 747-25A3431, dated March 6, 2008.
Prior to or concurrently with accomplishing the actions required by paragraph (f) of this AD: Install protective moisture curtains in the main equipment center in accordance with Boeing Service Bulletin 747-25A3430, Revision 1, dated October 9, 2008.
Note 1: The installation required by paragraph (g) of this AD is the same installation required by paragraph (f) of AD 2007-26-03, amendment 39-15305, for Boeing Model 747-200C and -200F series airplanes (AD 2007-26-03 specifies that the actions be done in accordance with Boeing Alert Service Bulletin 747-25A3430, dated February 15, 2007). Boeing Service Bulletin 747-25A3430, Revision 1, dated October 9, 2008, which affects Boeing Model 747-200F airplanes, variable numbers RR566 and RR551 through RR556 inclusive, is an alternative method of compliance for the requirements of paragraph (g) of AD 2007-26-03. Airplanes identified as Group 1, Group 3, and Group 6 airplanes in Boeing Service Bulletin 747-25A3430, Revision 1, dated October 9, 2008, must comply with paragraph (g) of AD 2007-26-03.
Installations accomplished before the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-25A3430, dated February 15, 2007, are considered acceptable for compliance with the corresponding action, paragraph (g) of this AD.
