Narrative:

Main transmission received from [domestic manufacturer] in a time since overhaul: 0.0 condition. Operator found two bolts safetied with zero torque on swash plate balance weight. Torque recommended 35.4-53.1 inch pounds as per bk117c2 rem.both oil cooler blower fan retention nuts found safetied with zero torque applied. Torque recommended 425-513 inch pounds as per bk117c2 amm.at initial post installation ground run; approximately two quarts of oil leaked from tail rotor output flange seal in the first minute of operation. Aircraft was shut down immediately. Further investigation revealed that the tail rotor output flange connecting part did not have the required seal sleeve installed at overhaul. After consultation with domestic manufacturer representatives; it was determined that load testing is performed with a slave tail rotor output flange installed. After testing the production flange is installed.apparently when the production flange was installed after load cell testing; it was installed without the sleeve that the output seal normally seats on. Our air ambulance company has been assured that [domestic manufacturer] is changing overhaul procedures to ensure that this discrepancy does not occur again. Discrepancies were corrected in accordance with manufacturer's recommendations. Suggest a follow-up with [domestic manufacturer]; ensuring change of procedures when overhauling main transmissions.

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Original NASA ASRS Text

Title: A Maintenance Inspector reports finding main transmission bolts on their BK-117-C2 swash plate balance weight and oil cooler blower fan retention nuts safetied with zero torque applied. At initial post installation ground run; the main transmission tail rotor output quill leaked approximately two quarts of oil. Manufacturer changes overhaul procedures.

Narrative: Main transmission received from [domestic manufacturer] in a Time Since Overhaul: 0.0 condition. Operator found two bolts safetied with zero torque on swash plate balance weight. Torque recommended 35.4-53.1 inch pounds as per BK117C2 REM.Both oil cooler blower fan retention nuts found safetied with zero torque applied. Torque recommended 425-513 inch pounds as per BK117C2 AMM.At initial post installation ground run; approximately two quarts of oil leaked from tail rotor output flange seal in the first minute of operation. Aircraft was shut down immediately. Further investigation revealed that the tail rotor output flange connecting part did not have the required seal sleeve installed at overhaul. After consultation with domestic Manufacturer Representatives; it was determined that load testing is performed with a slave tail rotor output flange installed. After testing the production flange is installed.Apparently when the production flange was installed after load cell testing; it was installed without the sleeve that the output seal normally seats on. Our air ambulance company has been assured that [domestic manufacturer] is changing overhaul procedures to ensure that this discrepancy does not occur again. Discrepancies were corrected in accordance with manufacturer's recommendations. Suggest a follow-up with [domestic manufacturer]; ensuring change of procedures when overhauling main transmissions.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.