Summary
The FAA proposes to supersede an existing airworthiness directive (AD) for Bombardier-Rotax GmbH Type 912 F, 912 S, and 914 F series reciprocating engines. That AD currently requires venting of the lubrication system and inspection of the valve train on all engines. That AD also requires venting of the lubrication system of all engines on which the lubrication system has been opened, and any engine on which the propeller has been rotated one full turn in the wrong direction. This proposed AD would require similar actions, and also require removing the existing part number oil dipstick from service and installing a new oil dipstick. This proposed AD results from the need to clarify the mandated procedures for inspections and venting. This proposed AD also results from the manufacturer discovering that under certain circumstances, the oil level in the oil tank can fall below the minimum level required to sustain proper engine lubrication. We are proposing this AD to prevent damage to the engine valve train due to inadequate venting of the lubrication system, which can result in an in-flight engine failure and forced landing.