SAIB NM-07-27

FAA Aircraft Certification Service

SPECIAL AIRWORTHINESS

INFORMATION BULLETIN http://www.faa.gov/aircraft/safety/alerts/SAIB

SAIB: NM-07-27 Date: April 17, 2007 This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin (SAIB) advises you, owners and operators, of Boeing Company Model 747-400F Series, Line 1361 – 1366 airplanes of a decision made by the FAA which relates to the number nine main deck side cargo door latch back-up fitting and Boeing Commercial Airplane Group’s Alert Service Bulletin 747-53A2659.

Background

Boeing records indicate the number nine main deck side cargo door (MDSCD) latch back-up fitting at Station 1897 was not correctly heat treated to engineering requirements. Heat treatment at the incorrect pressures, temperatures, and time may result in hydrogen embrittlement, thus ultimately could result in the failure of that part.

The FAA has concluded that this is not a unsafe condition because this manufacturing defect only relates to one of ten MDSCD latch back-up fittings. By design, the door latching system is safe with the failure of one of the ten latch fittings. Therefore, we have decided not to issue an AD at this time.

Recommendations

It is FAA’s recommendation that owners and operators of the affected airplanes be aware of this decision and refer to Boeing Commercial Airplane Group’s Alert Service Bulletin 747-53A2659 for guidance on inspection and replacement of the number nine MDSCD latch back-up fitting.

For Further Information, Contact:

Jason Deutschman, Aerospace Engineer, FAA Seattle Aircraft Certification Office; 1601 Lind Ave SW, Renton, WA 98057; phone: (425) 917-6449; fax (425) 917-6590;

email: jason.deutschman@faa.gov