Airworthiness Directive · Amendment 39-17701 · Fuel boost pump
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 737-300, -400, and -500 series airplanes; certificated in any category; identified as Groups 5, 6, 7, and 9 in Boeing Alert Service Bulletin 737-28A1212, Revision 2, dated October 18, 2012.
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-300, -400, and -500 series airplanes. This AD was prompted by fuel system reviews conducted by the manufacturer. This AD requires, depending on airplane configuration, replacing fuel pump power control relays with new relays having a ground fault interrupter (GFI) feature, installing ground studs and a bonding jumper, doing certain bonding resistance measurements, and changing the GFI relay position. This AD also requires revising the maintenance program to incorporate certain airworthiness limitations. We are issuing this AD to prevent damage to the fuel pumps caused by electrical arcing that could introduce an ignition source in the fuel tank, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.
For airplanes in Groups 5, 6, 7, and 9, Configuration 1, as identified in Boeing Alert Service Bulletin 737-28A1212, Revision 2, dated October 18, 2012 (airplanes on which Boeing Alert Service Bulletin 737-28A1212 was not done): Within 60 months after the effective date of this AD, install ground studs and a bonding jumper, replace fuel boost pump relays, and do certain bonding resistance measurements, in accordance with Part 1 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-28A1212, Revision 2, dated October 18, 2012. Doing the actions required by this paragraph terminates the requirements of paragraph (g) of AD 2011-12-09, Amendment 39-16716 (76 FR 33988, June 10, 2011), for airplanes in Groups 5, 6, 7, and 9, Configuration 1 only, provided that the requirements of paragraph (g) of this AD are done at the time given in AD 2011-12-09.
For airplanes in Groups 5, 6, 7, and 9, Configuration 2, as identified in Boeing Alert Service Bulletin 737-28A1212, Revision 2, dated October 18, 2012 (airplanes on which Boeing Alert Service Bulletin 737-28A1212, dated July 23, 2009 was done): Within 60 months after the effective date of this AD, install ground studs and a bonding jumper, change the GFI relay position, and do certain bonding resistance measurements, in accordance with Part 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-28A1212, Revision 2, dated October 18, 2012. Doing the actions required by this paragraph terminates the requirements of paragraph (h) of AD 2011-12-09, Amendment 39-16716 (76 FR 33988, June 10, 2011), for airplanes in Groups 5, 6, 7, and 9, Configuration 2 only, provided that the requirements of paragraph (h) of this AD are done at the time given in AD 2011-12-09.
For airplanes in Groups 5, 6, 7, and 9, Configuration 3, as identified in Boeing Alert Service Bulletin 737-28A1212, Revision 2, dated October 18, 2012 (certain airplanes on which Boeing Alert Service Bulletin 737-28A1212, Revision 1, dated August 27, 2010 was done): Within 60 months after the effective date of this AD, change the GFI relay position and do certain bonding resistance measurements, in accordance with Part 4 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-28A1212, Revision 2, dated October 18, 2012.
Concurrently with accomplishing the actions required by paragraph (g), (h), or (i) of this AD, or within 30 days after the effective date of this AD, whichever occurs later: Revise the maintenance program by incorporating Airworthiness Limitation 28-AWL-22 of Boeing 737-100/200/200C/300/400/500 AWL and Certification Maintenance Requirements (CMRs), Document D6-38278-CMR, Revision August 2012. The initial compliance time for the actions specified in AWL 28-AWL-22 of Boeing 737-100/200/200C/300/400/500 AWL and Certification Maintenance Requirements (CMRs), Document D6-38278-CMR, Revision August 2012, is within 1 year after accomplishing the installation required by paragraph (g), (h), or (i) of this AD, or within 1 year after the effective date of this AD, whichever occurs later.
After accomplishing the revision required by paragraph (j) of this AD, no alternative actions (e.g., inspections) or intervals may be used unless the actions or intervals are approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (l) of this AD.
