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Lycoming O-540-F1B5 engines with a S/N ending in “-40E” installed in Robinson R44 Raven I and R44 Cadet helicopters.
To advise aircraft operators and maintainers of possible burnt intake valves on O-540-F1B5 engines, which can result in partial, or complete loss of engine power.
This Continuing Airworthiness Notice (CAN) is prompted by reports received by Robinson Helicopters and Lycoming of operators experiencing a loss of engine power on certain Robinson R44 helicopters. For some incidents, the pilot noticed engine roughness, or a sudden momentary left yaw during flight. For these incidents, maintenance engineers were able to diagnose a burned valve using a compression check, prior to more significant symptoms developing.
Recommendations:
Robinson Safety Alert dated 14 October 2020 applicable to R44 I and R44 Cadet helicopters, advises that pilots/operators should observe the following precautions:
Lycoming Service Instruction (SI) No. 1577 dated 10 November 2020, is applicable to O-540-F1B5 engines with a S/N ending with “-40E” installed in R44 Raven I and R44 Cadet helicopters. This Lycoming SI advises maintainers accomplish the following:
Report findings to the CAA by completing a CA005D Defect Report form and submit the completed form to the CAA at CA005@caa.govt.nz or report findings via the online reporting system(external link).
Please include details of all findings and any other relevant technical information.
Note:
Lycoming Service Instruction (SI) No. 1577 dated 10 November 2020(external link)