SAIB NE-06-12

SPECIAL AIRWORTHINESS

INFORMATION BULLETIN

Aircraft Certification Service Washington, DC

U.S. Department of Transportation Federal Aviation Administration

NE-06-12 December 2, 2005 http://www.faa.gov/aircraft/safety/alerts/SAIB This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin advises you, registered owners, operators, and certificated repair facilities of all aircraft equipped with Rolls-Royce Corporation (RRC) engine models 250-C30R/3, -C30R/3M, -C47B, and -C47M of the new release of a “Reversionary Governor” configuration Electronic Control Unit (ECU). The new configuration is an improvement for the Model 250 series IV Full Authority Digital Electronic Control (FADEC) single engine ECU. The new configuration ECU will be provided at no cost to all operators who are registered with RRC prior to December 31, 2005. These engines are installed on, but not limited to, Bell Helicopter Textron 407, and MD Helicopters Inc. 600N helicopters.

Background

Risk analysis and safety management programs indicate the addition of a “Reversionary Governor” to the EMC-35A ECU will reduce the frequency of reversions to manual mode resulting in reduced safety risks.

RRC has modified the existing 250 ECU to add a reversionary governor to the Primary control. This new configuration is currently in the final stages of FAA certification.

RRC has published Commercial Service Letters CSL-3208 for the 250-C30 Series and CSL-6113 for the 250-C47 Series to introduce the Reversionary configuration to the field and to provide directions for registration.

Recommendations

We strongly recommend that you register prior to the deadline to obtain the improved “Reversionary Governor” configuration ECU at no cost and install it as soon as practicable.

For Further Information Contact

Khailaa Hosny, Aerospace Engineer, FAA Chicago ACO, ACE-118C, Chicago, Illinois 60018; phone: (847) 294-7134; fax: (847) 294- 7834; email: khailaa.hosny@faa.gov.