TEO-540-A1A Engine Maintenance Manual
© 2021 Avco Corporation. All Rights Reserved 05-10
February 2021 Page 9
YO-233-B2A Engine Maintenance Manual
05-10 - TIME LIMITS
1. General
A. Engine maintenance inspections are based on time intervals as shown in the Engine
Inspection Schedule. All inspections must be completed no later than 10 hours after the
specified time interval for the inspection.
2. Engine Inspection Schedule
A. The Engine Inspection Schedule shows the inspections that must be done for engines in this
manual. The scope of engine inspections includes visual observations during engine servicing
or maintenance as well as inspections based on progressive time intervals after the engine is
put into service. Engine inspections start from 10 hours and go to 25, 50, 100, 400, 500, and
1000-hour inspections.
Engine Inspection Schedule
During engine servicing or maintenance
“Visual Inspection” in Chapter 05-
20
Initial 10-hour engine inspection (for new, rebuilt, or
overhauled engines)
“10-hour Initial Engine Inspection”
in Chapter 05-20
• After 25 hours of initial operation of new or repaired or
rebuilt/overhauled engines or the first 6 months since the
engine was placed back into service (whichever occurs first)
• If one or more new engine cylinders and/or piston rings
have been installed
• If the rate of oil consumption has not stabilized, repeat this
inspection after the next 25 hours of operation
“25-hour Initial and Routine Engine
Inspection” in Chapter 05-20
• 25 hours after 25-hour Initial Operation Inspection
• After every 50 hours of operation or every 4 months
(whichever occurs first)
“50-hour Engine Inspection” in
Chapter 05-20
After every 100 hours of operation and annually*
“100-hour or Annual Engine
Inspection” in Chapter 05-20
After every 400 hours of operation
“400-hour Engine Inspection” in
Chapter 05-20
After every 500 hours of operation
“500-hour Engine Inspection” in
Chapter 05-20
After every 1000 hours of operation
"1000-hour Engine Inspection" in
Chapter 05-20.
Time Between Overhaul (TBO)
2200 hours or 12 years after engine placed in service, rebuilt or
overhauled (whichever occurs first).
Direct Drive Overhaul Manual
*More frequent inspections could be necessary for engines operated in particulate-laden or extremely
humid, cold, damp environments.
NOTICE: An operational ground check must be completed prior to and after each inspection, after
maintenance, and after engine overhaul. Refer to Chapter 72-00.
NOTICE: Inspections in this manual apply to the engine and not to the aircraft. Refer to the
airframe manufacturer’s maintenance manual for inspection information on airframe
components.
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