O plano da sua pergunta é o Saab 37 .
De acordo com x-plane.org sobre este plano -
Emergency power is supplied by a ram air turbine just before the left wing leading edge, which extends automatically on hydraulic power failure, and just before touch down. (Earlier, it was also always deployed whenever the landing gear was down.)
Eles citam Air Power Journal, Summer 1993, várias edições do FlygvapenNytt e outros materiais informativos da força aérea sueca.
A Wikipédia sueca também diz a mesma coisa -
On some military aircraft, such as the Saab 37 Viggen, the RAT is used during takeoff and landing for the pilot to be able to maneuver the plane in case of an engine failure at low altitude.