refer to items that have a TBO assigned and are authorized to be
overhauled, and CC for items changed on an as-needed basis.
coded RC or TC are considered limited service life items and will be
replaced as follows:
Retirement Life Components.
Items coded RC are finite life
The MAOT for these items has been determined through
engineering estimates and/or actual operational experience.
circumstance, will any RC item be subjected to any type of overhaul
When possible these items should be scheduled for replacement in
conjunction with the nearest scheduled inspection, or other
maintenance action prior to the expiration of the items MAOT.
published MAOT may be exceeded only under the conditions stated in
to reduce downtime by combining component replacement with
other scheduled maintenance actions.
If no scheduled
maintenance actions are due within the tolerance window,
the TBO replacement due time shall not be extended.
Time Between Overhaul Components.
Items coded TC must be
removed from service and returned to a depot level facility for
overhaul when the item has reached its TBO.
Only under the
TC component be authorized to exceed the published TBO.
possible TBO items should be replaced in conjunction with other
scheduled maintenance or inspections. To minimize downtime an
"early/late" replacement tolerance window has been established.
tolerance window enables the adjustment of the TBO due time to
coincide with other scheduled maintenance actions.
with the tolerance window, some items may come due for replacement at
times not compatible with other scheduled maintenance actions. If
there are no other scheduled maintenance actions due within the
tolerance window, the tolerance window will not be used.
(1) For components with a TBO of 400 hours or more, the removal
time may be varied above or below the assigned TBO by 75 hours.
(2) For components with a TBO of less than 400 hours, the
removal time may be varied above or below the assigned TBO by 10