Lateral mixer output link assembly (mixer link), part number 600N7636

SAIB: SW-07-17 February 16, 2007 http://www.faa.gov/aircraft/safety/alerts/SAIB This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin (SAIB) alerts owners, and operators of MD Helicopters Inc. (MDHI) model 600N helicopters that the lateral mixer output link assembly (mixer link), part number 600N7636, may develop cracks which radiate from the bearing bores on the link ends. MDHI has issued a service bulletin to perform inspections of the mixer link . The service bulletin is available on the company web site at www.mdhelicopters.com. This SAIB applies to all MDHI model 600N Helicopters.

Background

One mixer link, P/N 600N7636-1, from an in service model 600N helicopter was found to have a crack through the bearing end area of the link. Two additional 600N7636 mixer link parts from spares have been reported with cracks in the bearing end area. Inspections of the mixer link should be performed as soon as possible.

Recommendations

As soon as possible remove mixer links, part numbers 600N7636-1,-3, and do visual and eddy current inspections of the bearing end areas (See MDHI Service Bulletin SB600N- 044, dated 16, February 16, 2007). If any cracks are detected in the mixer links, replace with airworthy parts before further flight.

For Further Information, Contact

Jon Mowery, Aerospace Engineer, Los Angeles Aircraft Certification Office, ANM-120L 3960 Paramount Blvd, Lakewood CA 90712 Telephone (562) 627-5322, fax: (562) 627-5210 Email: [email protected]