Continental Motors is working with the FAA to ensure that owners and operators of aircraft equipped with Continental IO-520/550 and some IO-470 engines “will not be burdened with unnecessary costs” by a mandatory service bulletin that could lead to an airworthiness directive requiring replacement of some camshaft gears, the company said in an announcement.
AOPA participated in an April 14 teleconference with the FAA and several user groups to discuss ramifications of the mandatory service bulletin, and is encouraged that Continental Motors has committed to amending its provisions to mitigate their impact, said David Oord, AOPA senior director of regulatory affairs.
On April 18, AOPA reported that the mandatory service bulletin calls for replacing the camshaft gear “on all engines currently configured with camshaft gear P/Ns 631845, 655430, 655516, or 656031 within 100-hours of operation, at the next engine overhaul (not to exceed 12 years engine time in service), or whenever the camshaft gear is accessible, whichever occurs first, with camshaft gear P/N 656818.”
That requirement generated considerable reaction among owners because replacing the camshaft could require significant dismantling of affected engines, some of which are fresh out of overhaul.
“Continental Motors is working diligently with the FAA to make significant amendments to MSB05-8B. We expect this to happen in the next 15 days,” the company said.
Continental Motors said it is working on three main issues to lessen the potential burden. They include changing the mandatory camshaft replacement “to a visual inspection procedure allowing ‘on condition’ operation until the engine is overhauled, replaced, or the gear is accessible”; a change to the mandatory service bulletin’s time limit “to values that still ensure that the appropriate level of safety is attained, but does not dictate a mandatory overhaul time limit”; and publishing an alternative means of compliance (AMOC) “to allow camshaft gear replacement without complete engine disassembly.”
AOPA has been in contact with Continental Motors and will continue to be engaged with the manufacturer “to better clarify and quantify the issue and mitigate it by the most appropriate means,” Oord said.