SAIB SW-04-71

SPECIAL

AIRWORTHINESS

INFORMATION

BULLETIN

Aircraft Certification Service Washington, DC

U.S. Department of Transportation Federal Aviation Administration

SW-04-71 July 14, 2004 www.faa.gov - Search "SAIBs" This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin alerts you, owners and operators of Eurocopter model EC 120B aircraft, of reports of loss of the plug from the main gearbox (MGB) input flange, leading to the loss of oil from the MGB. Eurocopter has issued Service Bulletin (SB) No. 63-010, Rev. 0, dated February 4, 2004, titled, “Subject: Main Rotor Drive. Installation of the New MGB Input Flange Plug”.

Reference Eurocopter EC120 B Service Bulletin No. 63-010, Rev. 0, dated February 4, 2004

Background

We have received reports concerning loss of the plug from the MGB input flange, leading to the loss of oil from the MGB, indicated by illumination of the oil pressure warning light. The security of the plug in its seat depends on the tightness of the fit and the compression strength of the plug. Loss of the plug is due to the loss of elasticity of the elastomer. The SB modification consists of replacing the original plug with a plug of greater volume that increases its compression strength and thus improves its security.

Recommendations

We recommend that you incorporate the referenced SB for aircraft with serial numbers below S/N M516.

We also recommend that you become familiar with the Rotorcraft Flight Manual Transmission Emergency procedures for MGB low oil pressure.

For Further Information Contact

Mr. Eric Haight, Aerospace Engineer, FAA Rotorcraft Directorate, ASW-111 Rotorcraft Standards Staff, Fort Worth, Texas 76193-0110; phone: (817) 222-5204; fax: (817) 222-5961; email: eric.haight@faa.gov

For Copies of the SB, contact American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, TX 75053-4005; phone: (972) 641-3460; fax: (972) 641-3527.