Airworthiness Directive · Amendment 39-18364 · Fire protection
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 737-400 series airplanes, certificated in any category, having serial numbers 23865, 24231, 24706, 24474, 25417, 27003, 27149, 25375, 26281, 28661, and 28881, as modified by Supplemental Type Certificate ST01114WI (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/f9490633c04cbc8286257301006ed621/$FILE/ST01114WI.pdf).
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-400 series airplanes, as modified by a certain supplemental type certificate. This AD was prompted by the discovery of a design drawing error regarding placards that identified incorrect squibs and pressure switches for certain fire extinguisher bottles. This AD requires a detailed inspection of certain cargo placards to determine if they are the correct placards and in the correct location, a detailed inspection of the harnesses to verify that they are marked and installed correctly, and corrective action if necessary. We are issuing this AD to detect and correct incorrectly installed harnesses for the cargo fire suppression system bottles, which could result in an incorrect activation sequence of the bottles, the inability to suppress a cargo fire quickly, and a possible uncontrollable fire.
Within 6 months after effective date of this AD, do a detailed inspection of Advanced Aircraft Extinguishers cargo fire protection system (FPS) placards to determine if they are the correct placards and in the correct location, and do all applicable corrective actions, in accordance with the “SERVICE BULLETIN INSTRUCTIONS” of Advanced Aircraft Extinguishers Service Bulletin TFA10-26-0020, Revision IR, dated January 12, 2015. Do all applicable corrective actions before further flight.
Within 6 months after the effective date of this AD, do a detailed inspection of the harnesses to verify that they are correctly marked and installed, in accordance with the “SERVICE BULLETIN INSTRUCTIONS” of Advanced Aircraft Extinguishers Service Bulletin TFA10-26-0020, Revision IR, dated January 12, 2015. If any harness is not marked or installed correctly, before further flight, do steps C.(5) through C.(11) specified in and in accordance with the “SERVICE BULLETIN INSTRUCTIONS” of Advanced Aircraft Extinguishers Service Bulletin TFA10-26-0020, Revision IR, dated January 12, 2015, except as required by paragraph (i) of this AD.
Where Advanced Aircraft Extinguishers Service Bulletin TFA10-26-0020, Revision IR, dated January 12, 2015, specifies contacting the manufacturer for appropriate action: Before further flight, repair in accordance with a method approved by the Manager, Wichita Aircraft Certification Office (ACO), FAA.
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
