sack duty (hours, time)

compression sack, stuff sack

daysack, assault sack / pack, patrol / day pack, Northern Ireland (NI) patrol sack

flying hours / logged flight hours

logged flight hours / flying hours

man hours of duty

mean time between repairs (flying hours)

time to first overhaul (flying hours)

duty, off duty

duty, on duty

engineering sack, other arms Bergen, turtle backpack

jump sack

hit the sack

sack

sack dummy

sack rat

Sad Sack

snore sack

hours flown in combat

cryptanalyst hours

maintenance by flight hours

airframe flying hours

assigned life (of an aircraft in flying hours)

engine logged hours

helicopter logged hours

total airframe flying hours

in the hours of daylight

Watt hours (Wh) rating

full time military duty

part time duty

zone standard time (zone time) (ZST)

time to climb / climb time

time-gain control / gain time control