SPECIAL AIRWORTHINESS INFORMATION BULLETIN

Aircraft Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration

SW-07-29

April 18, 2007

This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin (SAIB) alerts owners and operators of Bell Helicopter Textron, Inc. and Agusta S.p.A. Model helicopters (listed in table 1) with Aeronautical Accessories, Inc. (AAI) part number 412-321 series high skid gear crosstubes (crosstubes) installed in accordance with AAI’s STC No. SR01052AT, that the crosstubes may develop cracks and fail prior to reaching the FAA approved life limit. AAI has issued an Operations Safety Notice (OSN) which state operators should perform inspections as soon as possible of both the forward and aft crosstubes. This OSN is available on the company web site at www.edwards-assoc.com. The OSN is listed under Technical Bulletins as AA-07024NR and dated March 27, 2007.

Table 1

Manufacturer	Model
Bell Helicopter Textron, Inc	412, 412EP, and 412CF
Agusta S.p.A.	AB412 and AB412EP

Background

Three reports from the field of failed aft crosstubes have been reported to AAI. Two of those failures occurred during landing. The other failure occurred during transport of the aircraft on ground handling platform equipment. Also, in one case during landing, the aft crosstube failed and subsequently the front cross tube failed causing the helicopter to lean severely on the failed right side.

Recommendations

As soon as possible, perform a maintenance inspection of the forward and aft cross tubes in accordance with AAI, Instructions for Continued Airworthiness (ICA), for crosstubes, Report No. AA-01136, Revision “C,” dated July 30, 2002, Section 3.0. If any crack or any damage outside the limits specified in the ICA is found, replace with airworthy parts before further flight.

For Further Information, Contact

Marc Belhumeur, Aerospace Engineer, Rotorcraft Certification Office, ASW-170, 2601 Meacham Blvd., Fort Worth, Texas 76193; phone: (817)222-5177; fax: (817) 222-5783; email: mark.belhumeur@faa.gov.