AOPA Wants McCauley NPRM Withdrawn
AOPA says the FAA should either withdraw a proposed AD setting life and operating limits on a couple of McCauley propellers or provide justification for imposing the rules. Last November, the FAA issued a Notice of Proposed Rulemaking that, if adopted, would affect the props on about 1,000 Beech Bonanzas, T-34s and Navions. The rule would put a 10,000-hour life on C406 and C409 props and also prevent them from being operated continuously at the common setting of between 2350 and 2450 RPM with 24 inches or higher of manifold pressure. The FAA says it issued the proposed AD based on test data supplied by McCauley and it's intended to prevent hub and blade failure in the props. But AOPA's Luis Guittierez said there is no evidence that any of the props have failed. "AOPA questions the justification for this restriction given that C406/C409 propellers have been safely operating for almost 30 years with no identified safety issues in this engine operating range," Gutierrez said. "Plus, AOPA could not find any accidents or incidents attributable to propeller blade or hub failure." In addition to the operating restriction, the AD could prove costly to many affected owners. Props for which the service life is unknown would have to be scrapped immediately and the 10,000-hour limit would affect the value of high-time aircraft. Guittierez also says the FAA ignored the normal process in proposing the AD in that it relied solely on manufacturer's data and did not take into account the actual field experience with these props.