AOPA Pilot Magazine - October 2017 - 93

P&E

SAVVY MAINTENANCE

Saxton at Twin Cessna Flyer all agreed to
join hands in dealing with this crisis.
On April 14, 2017, our coalition had a productive and candid hour-long discussion
with the Atlanta ACO and FAA Engine and
Propeller Directorate. Although the FAA
representatives couldn't tell us what the
agency was going to do about MSB05-8B (as
this had not yet been decided), we got the
impression they were as surprised by what
Continental was proposing as we were. One
FAA employee told us emphatically, "We
do not intend to mandate the MSB as written." He said the FAA had asked Continental
to make some revisions, and then would be
convening a formal review board to decide
what corrective action to take. We asked if
we could submit a position paper on behalf
of the affected owners for consideration by
the corrective action review board during its
deliberations, and they said sure.
MAKING OUR CASE

Our little group went to work, gathering all
the information we could about the failure

history of these camshaft gears; talking to
overhaul shops to find out what they were
finding during overhauls and other teardown inspections; and delving into the
technical aspects of metallurgy, crack propagation, fatigue limits, and other arcana.
In the meantime, on April 20, Continental
issued a press release stating that the company was "working diligently with the
FAA to make significant amendments to
MSB05-8B. We expect this to happen in
the next 15 days." Continental indicated the
revised MSB would include a program of
repetitive inspections that would allow the
camshaft gears to remain in service "on condition" until the next overhaul.
On May 1, our coalition submitted its
10-page paper to the FAA. In it, we stated
that we didn't object to an AD mandating
gear replacement at overhaul, but we were
adamantly opposed to any FAA mandate of
preemptive gear replacement or repetitive
gear inspections. (Performing such inspections would require engine removal on some
aircraft models, and substantial disassembly

on others.) We furnished some calculations
of camshaft gear failure rates demonstrating that the camshaft gear is arguably the
most reliable, least failure-prone steel component of the engine. (Connecting rods and
crankshafts fail much more often than camshaft gears do.) We argued forcefully that the
extremely low crankshaft gear failure rate did
not rise to the level of "an unsafe condition"
required to justify the issuance of an AD.
END GAME

May and June passed with no word from
Continental. Then in early July, Oord told
the members of our group Continental was
about to issue the long-awaited revised
MSB and had asked to discuss it with us
prior to publication. We were surprised and
delighted that Continental was reaching out
to us, and agreed to a meeting on July 13.
Continental told us it was planning
to release a new MSB05-8C the next
day. The new MSB would call for visual
inspections of older-style camshaft gears
at every annual or 100-hour inspection

B R E A K T H R O U G H !

CUBCRAFTERS.COM/BREAKTHROUGH

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http://www.CUBCRAFTERS.COM/BREAKTHROUGH
Table of Contents for the Digital Edition of AOPA Pilot Magazine - October 2017
