Israel's air force has used a Boeing 707-300 to trial a missile-defence system intended for deployment on board commercial aircraft.
The aircraft, which carries air force designation 272, is close to 40 years old and was previously in service with operators including British Caledonian.
Israeli firm Elbit Systems has used the four-engined jet to conduct a series of test flights with its C-Music infra-red countermeasures system.
The equipment, fitted to the aft fuselage of the aircraft, is designed to protect large jets against assault by portable shoulder-launched weapons.
Elbit has not detailed the test regime, citing the sensitive nature of the programme, but says the system was "proven effective, successfully performing all of the needed functions".
C-Music is a combined defence installation comprising an infra-red missile-warning system and directed infra-red laser, mounted in a turret, designed to disrupt heat-seeking missiles.
Elbit claims there is "considerable interest" from commercial and VIP aircraft operators, pointing out that the system has been chosen by the Israeli government for the country's entire commercial airline fleet.