Airworthiness Directive · Amendment 39-19893 · Fuel
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series airplanes, certificated in any category, line numbers (L/Ns) 1 through 1229 inclusive.
The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747- 200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series airplanes. This AD was prompted by fuel system reviews conducted by the manufacturer indicating that the existing bond path design provides insufficient bond resistance margin between the fuel pump motor/impeller and structure. This AD requires replacement of the bonding jumpers on the auxiliary power unit (APU) fuel pump. This AD also requires, for certain airplanes, installation of a second bonding jumper; an inspection of the override/jettison fuel pumps and transfer/ jettison fuel pumps to determine if the bonding jumper has a one-piece braid or two-piece braid and replacement of the bonding jumper if necessary; and replacement of the bonding jumper on the electrical scavenge fuel pump. The FAA is issuing this AD to address the unsafe condition on these products.
The definitions specified in paragraphs (g)(1) through (4) of this AD apply.
(1) Group 1 airplanes: L/Ns 1 through 167 inclusive.
(2) Group 2 airplanes: L/Ns 168 through 971 inclusive.
(3) Group 3 airplanes: L/Ns 972 through 1161 inclusive.
(4) Group 4 airplanes: L/Ns 1162 through 1229 inclusive.
Within 60 months after the effective date of this AD, do the applicable actions specified in paragraphs (h)(1) through (4) of this AD, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-28-2228, Revision 1, dated September 27, 2001.
(1) For Groups 1, 2, and 3 airplanes: Do the actions specified in paragraphs (h)(1)(i) and (ii) of this AD.
(i) Do a general visual inspection of the six override/jettison fuel pumps to determine if the bonding jumper has a one-piece braid or two-piece braid. If the bonding jumper has a one-piece braid, within 60 months after the effective date of this AD, replace the existing bonding jumper.
(ii) Install a second bonding jumper.
(2) For Groups 1, 2, and 3 airplanes with horizontal stabilizer fuel tanks: Do the actions specified in paragraphs (h)(2)(i) and (ii) of this AD.
(i) Do a general visual inspection of the two transfer/jettison fuel pumps to determine if the bonding jumper has a one-piece braid or a two-piece braid. If the bonding jumper has a one-piece braid, within 60 months after the effective date of this AD, replace the existing bonding jumper.
(ii) Install a second bonding jumper.
(3) For all airplanes: Replace the bonding jumpers on the auxiliary power unit (APU) fuel pump.
(4) For Groups 1 and 2 airplanes: Replace the bonding jumper on the electrical scavenge fuel pump.
