AWB 63-3 Issue 2 - 10 October 2003

Robinson R44
Lower Actuator Bearing Mounting Bracket

1. Effectivity

Robinson R44 Lower Actuator Bearing Mounting Bracket

2. Purpose

Advise operators and maintainers of R44 helicopters of the potential of unanticipated loss of power to the rotor, resulting in a forced autorotative landing and with the additional possibility of the engine exceeding design RPM.

3. Background

Routine maintenance discovered an extensive crack in the mounting bracket.

This bracket is a vital part of the R44 drive train from the engine to the rotor. If this bracket should fail, main drive belt tension would be lost almost immediately. This would result in a forced autorotative landing, At the same time, because the engine would be suddenly disconnected from the drive train while running at almost full power, the engine may well exceed design RPM.

4. Recommendation

CASA recommends that people maintaining the R44 pay critical attention to this bracket during routine maintenance inspection of the scroll, and ensure any damaged brackets are replaced, and that any minor damage to the edges at the ends of the bracket are removed in an approved manner. All instances of cracking in this bracket should be reported immediately to CASA.

5. Enquiries

Enquiries regarding the content of Airworthiness Bulletins should be made via e-mail (AirworthinessBulletin@casa.gov.au).