SAIB NM-11-45

FAA Aviation Safety

SPECIAL AIRWORTHINESS

INFORMATION BULLETIN SAIB: NM-11-45 SUBJ: Doors: Cargo/Baggage Doors Date: August 1, 2011 This is information only. Recommendations aren’t mandatory.

CORRECTION: The third paragraph incorrectly referenced ATR instead of M7 Aerospace service bulletins.

Introduction

This Special Airworthiness Information Bulletin (SAIB) advises registered owners and operators of ATR - GIE Avions de Transport Regional Model ATR42 and ATR72 airplanes modified by M7 Aerospace LP Supplemental Type Certificate (STC) ST01189WI, of the possibility of cracking of the upper hinges of the aft cargo door located in the cabin.

Background

We received two reports of a crack in a hinge lug of the upper hinge of the aft cargo do or on a Model ATR42 airplane and a Model ATR72 airplane, both modified by STC ST01189WI. On one airplane a crack was found in a lug on the forward upper hinge (part number (P/N) WAHN-01A); on the other airplane a crack was found in a lug on the aft upper hinge (P/N WAHN-02A). Both cracks went through the entire lug thickness.

Due to these incidents, M7 Aerospace Service Bulletins ATR42-53-030 and ATR72-53-017 for ATR42 and ATR72 model series airplanes, respectively, modified by STC ST01189WI were issued.

The service information provides operators with guidelines for replacing upper hinges having P/N WAHN-01A and P/N WAHN-02A, with new hinges. The service information also provides operators with guidelines for performing repetitive eddy current inspections of the hinge lug bores for cracking until the hinges are replaced.

Hinge tang failure does not present a potential for fatal injury, due to the redundancy of the door design; the door can still carry full certificated flight loads with the complete hinge removed (not just failure of one hinge tang).

At this time, the airworthiness concern is not an unsafe condition that would warrant airworthiness directive (AD) action under Title 14 of the Code of Federal Aviation Regulations (14 CFR) part 39.

Recommendations

The FAA recommends that all owners and operators of ATR - GIE Avions de Transport Regional Model ATR42 and ATR72 airplanes modified by STC ST01189WI comply with the actions outlined in Service Bulletins ATR42-53-030 and ATR72-53-017, both dated May 24, 2011.

For Further Information Contact

Andrew McAnaul, Aerospace Engineer, FAA, ASW-150, 10100 Reunion Place, Suite 650, San Antonio, Texas, 78216; phone: (210) 308-3365; fax: (210) 308-3370; e-mail:

andrew.mcanaul@faa.gov.

2 For Related Service Information Contact

M7 Aerospace, LP, 10823 N.E. Entrance, San Antonio, Texas, 78216; phone: (210) 824-9421; fax:

(210) 820-8609.