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ChrisPilot
06-24-2014, 06:48 AM
Hi All

MT Propeller has recommended to shorten the TBO for CS props to 1/3 if it has been used for snap-rolls and gyroscopic maneauvers. Ref http://www.mt-propeller.com/pdf/sbs/sb1ak.pdf
I can understand that hardcore unlimited maneuvers may reduce the lifetime of the prop (and engine), but I dont understand why MT is also shortening the calendar time from 6 years to 2 years between overhauls. I wonder what experience and practices that is out there for both experimentals and certified planes, and appreciate comments.

Fly safe
Christian :-)

WLIU
06-24-2014, 08:11 AM
I regret to report that my friends who fly some of the MT's hard are indeed sending them to the service center for work well before the original published TBO. Particularly the 2 blade props start "slinging" grease. My personal observation has been that the 3 blade props have fewer issues.

In the US, service bulletins are not regulatory. You can fly your prop until it starts having a problem. That said, the pilot/owner population that the bulletin addresses currently appears to be needing their props serviced well within the MT recommended hours and times.

Flying hard drives the maintenance bills up. Ya gotta pay to play.

All of that aside, Mr Muhlbauer has been a great supporter of the aerobatic community. He was in the MT booth at the Sun-N-Fun this spring and a couple of us made a point of stopping and saying thank you. I am sure that this bulletin was not published without careful consideration.

Best of luck,

Wes

cyav8r
06-24-2014, 07:12 PM
The SB you reference just says there needs to be an inspection every 1/3 of the TBO duration. It doesn't say the TBO has been reduced for acro ops. It also seems to be focused specifically on unlimited pilots and airshow guys who do lots of high power auto-rotation type maneuvers. So the guidance is similar to what Whirlwind recommends if I remember correctly.