SPECIAL AIRWORTHINESS INFORMATION BULLETIN

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

SW-07-22

March 22, 2007

This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin (SAIB) alerts owners and operators of all Eurocopter France (ECF) AS350B, AS350BA, AS350BB, AS350B1, AS350B2, AS350B3, AS350D (Astar) and AS355E (Twinstar) helicopters to a potential flight safety hazard concerning the serrated washers (part number 341A75-3000-20) on the lower servo-control rod end-fittings on flight control actuators. (See Figure 2)

NOTE: The target audience for this SAIB is the MAINTENANCE AND PILOT community for Eurocopter products.

Background

We have become aware of the potential for separation of, or excessive wear on, the inner tang of the serrated washers located on the servo control-rod end-fittings. This condition could lead to flight control disconnect and subsequent loss of aircraft control. Two fatal accidents have occurred after the servo-control rod end-fitting became detached from the servo-actuator.

Eurocopter issued a Telex (T.F.S. No. 00000379) dated 20 March 2007 for all AS350 and AS355E models concerning this issue.

Recommendations

We strongly recommend that mechanics and pilots of Eurocopter AS350 Astar and AS355E Twinstar helicopters perform the following actions:

Maintenance Actions

• Immediately inspect the serrated washers on the lower servo-control rod end-fittings for condition, security and appropriate measurement, as defined in the maintenance manual.

• Ensure the proper torque and measurement, as defined in the maintenance manual, of the lower servo-control rod end-fitting jam nut. Ensure the torque points are applied as prescribed by the maintenance manual.

• DO NOT use the lower servo-control rod end-fitting as a wrench attach point for torque application. When appropriate torque is applied, hardware should be torque striped to ensure unintended movement is easily identifiable.

• If the serrated washer appears worn, remove, discard, and replace with a new serrated washer. See Figures 1 and 2.

• Operators are requested to report missing tangs or excessive serrated washer inner tang wear and/or servocontrol rod end-fitting movement to the point of contact (POC) listed on this SAIB.

                                                                                          ILLUSTRATION (Figure 1)

                                                                                          ILLUSTRATION (Figure 2)

Pilot Actions

• Pilots should inspect the condition and security of the flight control system during pre-flight inspection, and immediately report any misalignment to maintenance personnel.

For Further Information Contact

Mr. Michael Hemann, FAA Rotorcraft Directorate, ASW-112 Standards Staff, Fort Worth, Texas 76193-0110; phone: (817) 222-5336; fax: (817) 222-5961; email: michael.hemann@faa.gov.

For Related Service Information Contact

American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, Texas 75053-4005; phone: (972) 641-3460, fax: (972) 641-3527.