Airworthiness Directive · Amendment 39-16395 · The Boeing Company Model 737-600, -700, -700C, -800, and -900 Series Airplanes
The Boeing Company Model 737-600, -700, -700C, -800, and -900 Series Airplanes
Superseded. A later AD replaced this one: AD 2011-20-07. Comply with the one in force.
This AD applies to The Boeing Company Model 737-600, -700, -700C, -800, and -900 series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 737-28A1201, Revision 1, dated May 28, 2009.
We are adopting a new airworthiness directive (AD) for certain Model 737-600, -700, -700C, -800, and -900 series airplanes. This AD requires replacement of the power control relays in the P91 and P92 power distribution panels for the fuel boost and override pumps with new, improved relays having a ground fault interrupter (GFI) feature, or installation and maintenance of universal fault interrupters (UFIs) using a certain supplemental type certificate. This AD results from fuel system reviews conducted by the manufacturer. We are issuing this AD to prevent pump housing burn-through due to electrical arcing, which could create a potential ignition source inside a fuel tank. This condition, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.
Comply with this AD within the compliance times specified, unless already done.
Within 60 months after the effective date of this AD, do the actions required in paragraph (f)(1) or (f)(2) of this AD.
(1) Replace the power control relays that are located in the R18, R19, R20, R21, R54, and R55 positions in the P91 and P92 power distribution panels for the fuel boost and override pumps with new, improved relays, part number KDAG-X4F-001, having a ground fault interrupter (GFI) feature, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-28A1201, Revision 1, dated May 28, 2009.
(2) Install and maintain TDG Aerospace universal fault interrupters (UFIs) using Supplemental Type Certificate ST02079LA.
Note 1: Boeing Alert Service Bulletin 737-28A1201, Revision 1, dated May 28, 2009, refers to Honeywell Service Bulletin 1151932-24-61 and Honeywell Service Bulletin 1151934-24-62, both Revision 5, both dated May 25, 2009, as additional sources of guidance for replacement of the power control relays in the P91 and P92 power distribution panels.
(g) Actions done before the effective date of this AD in accordance with Boeing Alert Service Bulletin 737-28A1201, dated February 19, 2007, are acceptable for compliance with the requirements of paragraph (f) of this AD, provided that Revision 5 of Honeywell Service Bulletins 1151932-24-61 and 1151934-24-62, both dated May 25, 2009, are used as additional sources of guidance.
