This Could Be A Pricey One, Folks...

The FAA has submitted a Notice of Proposed Rulemaking on a potential Airworthiness Directive aimed at McCauley Propellers, specifically model 3A32C406/82NDB-X and D3A32C409/82NDB-X Propellers (hereafter referred to as C406 and C409, respectively) mounted to Teledyne Continental Motors (TCM) IO-520, TSIO-520, or IO-550 reciprocating engines.

The NPRM affects owners and pilots of a variety of Beechcraft Bonanza models, as well as Navion aircraft equipped with TCM IO-550 and TSIO-520 series reciprocating engines.

"McCauley Propeller Systems recently conducted tests to measure vibratory stress on C406 and C409 propellers," the NPRM reads. "The tests identified a high stress condition that reduces the fatigue life and damage tolerance of C406 and C409 propellers when installed on TCM IO-520, TSIO-520, or IO-550 reciprocating engines."

"This condition, if not corrected, could result in blade or hub failure that could result in separation of a propeller blade and loss of control of the airplane."

Below is the unedited summary of the NPRM, as well as the estimated cost of compliance should an Airworthiness Directive be issued.

• SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) for McCauley Propeller Systems models 3A32C406/82NDB-X and D3A32C409/ 82NDB-X propellers, installed on Teledyne Continental Motors (TCM) IO-520, TSIO-520, or IO-550 reciprocating engines. These propellers are herein referred to as C406 and C409 propellers, respectively. This proposed AD would require adding an operational revolutions per minute (rpm) restriction on the C406 and C409 propellers, and installing an rpm restriction placard in the cockpit. This proposed AD would also add a 10,000-hour total time-in-service (TIS) life limit for these propellers. This proposed AD would also remove from service any propeller that has 10,000 hours or more total TIS, or that has an unknown total TIS. Also, this proposed AD would require initial and repetitive propeller blade inspections for damage, and repair if necessary. This proposed AD results from testing by the manufacturer that identified stress conditions that affect the fatigue life and damage tolerance of C406 and C409 propellers, when installed on TCM IO-520, TSIO-520, or IO-550 reciprocating engines. We are proposing this AD to prevent blade or hub failure that could result in separation of a propeller blade and loss of control of the airplane.

• COST OF COMPLIANCE: About 2,350 C406 and C409 propellers installed on airplanes of U.S. registry would be affected by this proposed AD. We also estimate it would take about 3 work hours per propeller to perform the proposed inspections and repairs, and each propeller would have three inspections per year. We also estimate it would take about 0.5 work hour to install the proposed cockpit placard, and about 950 airplanes would require the placard. The average labor rate is $65 per work hour. A replacement propeller blade would cost about $10,500. We estimate 500 propellers in the fleet (or about 21%) would require parts replacement. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $2,585,500.

Follow the links below to view the full NPRM, as well as to submit your comments electronically. Any comments on this proposed AD must be received by January 17, 2006.

FMI: Click Here To View The Complete NPRM, Click Here To Submit Comments Electronically (Affected Pilots And Owners Only)