SAIB NM-07-12

FAA Aircraft Certification Service SPECIAL AIRWORTHINESS INFORMATION BULLETIN http://www.faa.gov/aircraft/safety/alerts/SAIB

SAIB: NM-07-12 Date: November 27, 2006 This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin (SAIB) advises you, owners and operators of The Boeing Company Model 737-100, -200, -300, -400, and -500 aircraft to inspect the wire bundle W138 and add protection sleeves to the wire bundles for the equipment cooling blowers.

Background

This SAIB is prompted by reports that one operator experienced the illumination of the entire fire-warning panel. The left wing overheat light also illuminated. The crew reported that they were unable to silence the bell or extinguish the blinking lights. On the ground, maintenance found a significant section of wire bundle W138 behind the E3-4 shelf in the Electronic Equipment Bay completely burned away. The burned wires were a result of wire insulation damage caused by an electrical arc when the wires rubbed against the clamps on the cooling blowers. Recommendations

We recommend that you incorporate Boeing Special Attention Service Bulletin (SASB) 737-24-1163 Revision 1, dated June 26, 2006. This SASB provides instructions for inspection of the wire bundles for the equipment cooling blowers between the blowers and the wire bundle breakout. You should repair the wire bundles if necessary, and install protection sleeves.

For Further Information Contact

Binh V. Tran, Aerospace Engineer, FAA Seattle Aircraft Certification Office, 1601 Lind Avenue, SW, Renton, WA 98055-4056; phone: (425) 917-6485; fax: (425) 917-6590; email: [email protected].

For Service Bulletin Information Contact

Boeing Company at P.O. Box 3707, Seattle, WA 98124, or through the following website: https://www.myboeingfleet.com/boldweb/index .bhtml