Airworthiness Directive · Amendment 39-11480 · Boeing Model 737-300, -400, -500, -600, -700, and -800 Series Airplanes
Boeing Model 737-300, -400, -500, -600, -700, and -800 Series Airplanes
Model 737-300, -400, and -500 series airplanes, as listed in Boeing Alert Service Bulletin 737-29A1076, Revision 1, dated October 21, 1999; and Model 737-600, -700, and -800 series airplanes, as listed in Boeing Alert Service Bulletin 737-29A1077, Revision 1, dated October 21, 1999; certificated in any category.
This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 737-300, -400, -500, -600, -700, and -800 series airplanes. This action requires a one-time detailed visual inspection of certain wire bundles and hydraulic hoses for the electric motor driven pump (EMDP) for hydraulic system ``B'' located in the right main wheel well to detect discrepancies; and corrective actions, if necessary. This amendment is prompted by a report that the wire bundle to the EMDP had been chafed by the pressure hose for hydraulic system ``B'' on a Model 737-700 series airplane, and reports of failed or damaged case drain or pressure hoses on the EMDP for hydraulic system ``B'' on Model 737-400 series airplanes. The actions specified in this AD are intended to prevent electrical arcing due to chafing between certain hydraulic hoses and adjacent wire bundles, which could result in a consequent increased risk of fire.
Required as indicated, unless accomplished previously.
To prevent electrical arcing due to chafing between certain hydraulic hoses and adjacent wire bundles, which could result in a consequent increased risk of fire; accomplish the following:
Actions for Model 737-300, -400, and -500 Series Airplanes
(a) For certain Model 737-300, -400, and -500 series airplanes on which the actions specified by Boeing Alert Service Bulletin 737-29A1076, dated April 2, 1998, have not been accomplished: Within 90 days after the effective date of this AD, perform a one-time detailed visual inspection of wire bundle W0334 and the hydraulic case drain and pressure hoses for the electric motor driven pump (EMDP) for hydraulic system ``B'' to detect any discrepancy (e.g., damage or chafing of wire bundle W0334 and the hydraulic case drain and pressure hoses, and incorrect separation between those components), in accordance with Part 1 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-29A1076, Revision 1, dated October 21, 1999.
(1) If no discrepancy is found, no further action is required by this paragraph.
(2) If any discrepancy is found, prior to further flight, perform corrective actions in accordance with Part 1 of the Accomplishment Instructions of the alert service bulletin.
Note 2: For the purposes of this AD, a detailed visual inspection is defined as: ``An intensive examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an
intensity deemed appropriate by the inspector. Inspection aids such as mirrors, magnifying lenses, etc. may be used. Surface cleaning and elaborate access procedures may be required.''
(b) For certain Model 737-300, -400, and -500 series airplanes on which the actions specified by Boeing Alert Service Bulletin 737-29A1076, dated April 2, 1998, have been accomplished: Within 90 days after the effective date of this AD, perform a one-time detailed visual inspection of wire bundle W0334 and the hydraulic case drain and pressure hoses for the EMDP for hydraulic system ``B'' to detect any discrepancy (e.g., damage or chafing of wire bundle W0334 and the hydraulic case drain and pressure hoses; and incorrect separation between those components), in accordance with Part 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-29A1076, Revision 1, dated October 21, 1999.
(1) If no discrepancy is found, no further action is required by this paragraph.
(2) If any discrepancy is found, prior to further flight, perform corrective actions in accordance with Part 2 of the Accomplishment Instructions of the alert service bulletin.
Actions for Model 737-600, -700, and -800 Series Airplanes
(c) For certain Model 737-600, -700, and -800 series airplanes on which the actions specified by Boeing Alert Service Bulletin 737-29A1077, dated March 4, 1999, have not been accomplished: Within 90 days after the effective date of this AD, perform a one-time detailed visual inspection of wire bundle W5230 and the hydraulic case drain and pressure hoses for the EMDP for hydraulic system ``B'' to detect any discrepancy (e.g., damage or chafing of the W5230 wire bundle and the hydraulic case drain and pressure hoses; and incorrect separation between those components) in accordance with Part 1 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-29A1077, Revision 1, dated October 21, 1999.
(1) If no discrepancy is found, no further action is required by this paragraph.
(2) If any discrepancy is found, prior to further flight, perform corrective actions in accordance with Part 1 of the Accomplishment Instructions of the alert service bulletin.
(d) For certain Model 737-600, -700, and -800 series airplanes on which the actions specified by Boeing Alert Service Bulletin 737-29A1077, dated March 4, 1999, have been accomplished: Within 90 days after the effective date of this AD, perform a one-time detailed visual inspection of wire bundle W5230 and the case drain and pressure hoses for the EMDP for hydraulic system ``B'' to detect any discrepancy (e.g., damage or chafing of the W5230 wire bundles and the hydraulic case drain and pressure hoses; and incorrect separation between those components), in accordance with Part 2 of Boeing Alert Service Bulletin 737-29A1077, Revision 1, dated October 21, 1999.
(1) If no discrepancy is found, no further action is required by this paragraph.
(2) If any discrepancy is found, prior to further flight, perform corrective actions in accordance with Part 2 of the Accomplishment Instructions of the alert service bulletin.
