MAJOR ENGINE INSPECTIONA comprehen-
sive inspection performed to determine the
material condition of the engine. This inspection is
performed with the engine removed from the
MAL CODEMalfunction Description CodeA
three-character numeric or alphanumeric code, is
used to describe the malfunction occurring on or in
an item identified by a WUC.
MAN-HOURSThe total number of accumulated
direct labor hours (in hours and tenths) expended in
performing a maintenance action. Direct
maintenance man-hours are man-hours expended
by assigned personnel to complete the work
described on the source document. This includes
the functions of preparation, inspection,
disassembly, adjustment, fault correction,
replacement or reassembly of parts, and
calibration/tests required in restoring the item to a
serviceable status. It also includes such associated
tasks as checking out and returning tools, looking
up part numbers in the IPB, transmitting required
information to material control, and completing
documentation of the MAF.
MANAGEMENTA general term to denote central
executive direction and control of work by an
individual or organization specifically assigned
and funded to accomplish the function.
MANUFACTURERIndividual, company, firm,
corporation, or government activity engaged in the
fabrication of finished or semifinished products.
MATCHED SETA group of two or more separate
components that function together in a single
system and are normally removed, repaired,
checked, adjusted, calibrated, and installed
together. Replacement of a single component of a
matched system normally requires check/
adjustment/calibration of the matched set.
MATERIALAll items necessary for the equipment,
maintenance, and support of military activities
without distinction as to their application for
administrative or combat purposes, excluding ships
or naval aircraft.
MATERIAL COGNIZANCE CODESA two-
character, alphanumeric code which denotes
responsibility for exercising supply management
over items or categories of material.
MATERIAL CONDITIONReporting status with
respect to SCIR.
whereby all supply action documents in support. of
maintenance are key entered.
MCMission CapableMaterial condition of an
aircraft that can perform at least one and potentially
all of its missions. MC Hours = EIS Hours - NMC
MCNMaintenance Action Form (MAF) Control
NumberA serial number assigned to each
maintenance action. The MCN is system generated
MCRSMaterial Condition Reporting Status.
MDBA/AMaintenance Data Base Administrator and
MDRMaintenance Data Record or Maintenance
MDSMaintenance Data System.
MEASUREMetrology Automated System for
Uniform Recall and ReportingA metrology
system for the recall and reporting of test
equipment by means of ADP techniques, maintains
records of calibration and automatically recalls
items when due for calibration.
MECFAMaintenance Engineering Cognizant Field
MEPPMobile Electric Power Plant.
MESMMission Essential Subsystem Matrix
Published in OPNAVINST 5442.4, lists, for each
model, the equipment systems/subsystems that
must be on board and in working order before an
aircraft can qualify as mission ready.
METER CARDMetrology Equipment Recall
CardSource document used to update the
MEASURE. All actions to PME/TAMS are
reported to MEASURE via METER CARDS.
METER READINGMeter readings apply to only
those items that have a clock/meter installed.
Readings will be in time, cycles, or starts to the
nearest whole number.
METROLOGY The science of measurement or
determination of conformance to technical
requirements, including the development of
standards and systems for absolute and relative
MFMobile FacilityA relocatable tactical shelter,
and its related equipment. The principle applica-