failure-free operation

accident-free flying / mishap-free flying

mishap-free flying / accident-free flying

failure-free

knock-free operation

accident-free operation

free-flier operation

trouble-free operation

no-failure operation

clandestine operation; covert operation

humanitarian operation; humanitarian relief operation (HUMRO)

PZ operation (pick-up zone operation)

noncombatant evacuation operation (NEO); non-combat evacuation operation

contact-free war

contamination-free

fallout-free

free fall

free fall air drop

free fire zone

free mine

free naval control of shipping

free net

free neutron

free rocket

free-fall bomb

nuclear-free zone

toxic free area

free-fire area

impact free

mine free

weapons free zone (WFZ)

anti-aircraft free-flight rocket

free flight