SAIB SW-05-01 —

SW-05-01 October 7, 2004 www.faa.gov/certification/aircraft This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin alerts you, owners and operators of Eurocopter EC 155B, EC 155B1, AS 365N3, SA 366G1, and SA 366GA helicopters, that Eurocopter has issued Alert Telex Nos. 63A007, 63.00.12 and 63.05. These Alert Telexes require you to check the connections of the MGB main and auxiliary oil pressure switches, and to change over the switch connections should a cross connection exist.

Reference Eurocopter Alert Telex Nos. 63A007, 63.00.12, and 63.05, dated August 4, 2004

Background

Eurocopter has received a report of a crossed connection between the low-pressure switch of the MGB main lubrication system and the low- pressure switch of the MGB auxiliary lubrication system. Both electrical systems are identified by labels, which may become difficult to read due to aging. When cross connected, a failure of one of the lubrication systems will illuminate the failure warning light that corresponds to the other system. This would result in an erroneous interpretation, the most unfavorable case being failure of the main system illuminating the warning light that corresponds to the auxiliary system.

Recommendations

Due to the potential consequences of cross connection of the main and auxiliary oil pressure switches, we highly recommend that you comply with the referenced Eurocopter Alert Telexes to ensure the switches have not become cross connected during maintenance activities.

For Further Information Contact

Ed Cuevas, Aviation Safety Engineer, FAA Safety Management Group, ASW-112, 2601 Meacham Blvd., Fort Worth, Texas, 76137; phone: (817) 222-5355; e-mail: [email protected].

For copies of the Alert Telex, contact American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, Texas 75053- 4005, phone: (972) 641-3460, fax: (972) 641-3527.