first echelon maintenance

first echelon medical equipment maintenance

first fire mixture / first-fire mixture

echelon-to-echelon communications system

echelon maintenance

third echelon maintenance

second echelon maintenance

fifth echelon maintenance

contingency maintenance / special maintenance

depot maintenance (beyond O and I level activities, performed in an industrial-type facility) / D-level maintenance

maintenance checks / routine maintenance, scheduled tasks

maintenance idling (periodic running of engine for maintenance purposes)

organizational maintenance (O-level) (day-to-day work that standard airfield maintenance groups perform in support of airfield operations)

routine maintenance / scheduled tasks, maintenance checks

scheduled tasks / routine maintenance, maintenance checks

special maintenance / contingency maintenance

credible first strike capability

first aid facility

first aid kit

first hand information

first impression report (FIR) (post exercise)

first lieutenant = (брит.) lieutenant

first light

first responder (emergencies)

first response

first response unit

First Sergeant (1SGT)

first watch

first-aid skills

first-line reserve

individual first-aid kit (IFAK)

first lights

Petty Officer First Class (PO1)