Airworthiness Directive · Amendment 39-17413 · Oxygen
The Boeing Company Airplanes
Superseded. A later AD replaced this one: AD 2021-08-04. Comply with the one in force.
This AD applies to The Boeing Company airplanes, certificated in any category, as identified in paragraphs (c)(1), (c)(2), and (c)(3) of this AD.
(1) Model 737-700, -700C, -800, and -900ER series airplanes, as identified in Boeing Alert Service Bulletin 737-35A1121, Revision 1, dated November 7, 2011.
(2) Model 747-400F series airplanes, as identified in Boeing Alert Service Bulletin 747-35A2126, Revision 1, dated September 29, 2011.
(3) Model 767-200 and -300 series airplanes, as identified in Boeing Alert Service Bulletin 767-35A0057, Revision 1, dated November 17, 2011.
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-700, -700C, -800, and -900ER series airplanes, Model 747-400F series airplanes, and Model 767-200 and -300 series airplanes. This AD was prompted by reports indicating that certain crew oxygen mask stowage box units were possibly delivered with a burr in the inlet fitting. The burr might break loose during test or operation, and might pose an ignition source or cause an inlet valve to jam. This final rule adds a step to identify and label certain crew oxygen mask stowage box units that have already been inspected and reworked by the supplier, and allows operators to install new or serviceable crew oxygen mask stowage box units, and requires a general visual inspection for affected serial numbers of the crew oxygen mask stowage box units, and replacement or re-identification as necessary. We are issuing this AD to prevent an ignition source, which could result in an oxygen-fed fire; or an inlet valve jam in a crew oxygen mask stowage box unit, which could result in restricted flow of oxygen.
Within 24 months after the effective date of this AD: Do a general visual inspection to determine if the serial number of the crew oxygen mask stowage box unit is identified in the Appendix of Intertechnique Service Bulletin MXP1/4-35-175,
Revision 2, dated May 10, 2011, in accordance with the Accomplishment Instructions of the applicable Boeing alert service bulletin specified in paragraph (c)(1), (c)(2), or (c)(3) of this AD. A review of airplane maintenance records is acceptable in lieu of this inspection if the serial number of the crew oxygen mask stowage box unit can be conclusively determined from that review.
(1) If any crew oxygen mask stowage box unit has a serial number identified in table 1 of the Appendix of Intertechnique Service Bulletin MXP1/4-35-175, Revision 2, dated May 10, 2011: Before further flight, replace the crew oxygen mask stowage box unit with a new or serviceable unit, in accordance with the Accomplishment Instructions of the applicable Boeing alert service bulletin specified in paragraph (c)(1), (c)(2), or (c)(3) of this AD.
(2) If any crew oxygen mask stowage box unit has a serial number identified in table 2 of the Appendix of Intertechnique Service Bulletin MXP1/4-35-175, Revision 2, dated May 10, 2011: Before further flight, add the letter “I” to the end of the serial number (identified as “SER”) on the identification label, in accordance with the Accomplishment Instructions of Intertechnique Service Bulletin MXP1/4-35-175, Revision 2, dated May 10, 2011; and reinstall in accordance with the Accomplishment Instructions of the applicable Boeing alert service bulletin specified in paragraph (c)(1), (c)(2), or (c)(3) of this AD.
(3) If no crew oxygen mask stowage box unit has a serial number identified in the Appendix of Intertechnique Service Bulletin MXP1/4-35-175, Revision 2, dated May 10, 2011: Unless a records review was done to determine the serial number, before further flight, reinstall the crew oxygen mask stowage box unit, in accordance with the Accomplishment Instructions of the applicable Boeing alert service bulletin specified in paragraph (c)(1), (c)(2), or (c)(3) of this AD.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
