The PMD and PMS are visual inspections that include some
The aircraft and associated equipment is checked
to ensure satisfactory performance during the interval between phase
Disassembly of components is not required unless major
faults are found, but removal of screens, panels, and inspection
plates may be required to complete the inspection.
(1) PMD Inspection.
Inspection required after the last flight of
the mission day or before the first flight of the next mission day.
Flights/missions extending beyond 24 hours from the first take off of
the mission, that calls for intermediate stops, loading/unloading,
servicing, and so on does not require a new PMD inspection to complete
The PMD is due at first engine shutdown or crew change
after passing the 24-hour mark from the first take off of the mission.
Refer to the individual aircraft PMD checklist for specific PMD
(2) PMS Inspection.
The PMS is similar to a PMD inspection with
the primary difference being when it is due.
Usually a PMS is due
every 10 flying hours or 14 days, which ever occurs first; however,
the interval may vary depending on the type of aircraft.
This type of
inspection is considered a recurring inspection and must be listed on
the aircraft DA Form 2408-18.
The tolerance window stated in
interval. Several PMS checklists state that when the forecasted flying
hours for a mission, is greater than the number of hours remaining
until the PMS is due, the inspection must be completed before the
start of the mission; however, some checklists permit an extension of
the due time. Deliberate over-flights of the PMS due time shall be
avoided, any extension or deferment of the PMS could be inherently
Unless specifically authorized in the applicable PMS
checklist, or approved by the Commander under the provisions in
paragraph 2-2 or 2-3, over-flight of the PMS inspection interval is
Phase Maintenance Inspection.
The PM inspection is a thorough
and searching examination of the aircraft and associated equipment.
Removals of access plates, panels, screens, and some partial
disassembly of the aircraft is required to complete the inspection.
PM inspections are due after an appointed number of flying hours or
calendar interval from the completion of the last PM inspection. PM
inspection cycle numbers and requirements are listed in the applicable
Requirements may vary depending on the PM
aircraft PM checklist.
PM inspections are numbered consecutively
inspection cycle number.
within a cyclic system. When the last inspection in the cycle is
completed, the numbering system restarts with the next inspection due
For example; aircraft that have a four inspection
being number one.
cycle, the phase inspections will be number 1, 2, 3, 4 (end of first
cycle); restart, perform inspection number 1, 2, 3, 4 (end of second
PM inspections must be completed in sequence. If
cycle), and so on.