Max RAT Retraction?

Max RAT Retraction?

• A. 170 / .40
• B. 180 / .45
• C. 190 / .50
• D. 200 / .55

Answer: (B)

Max RAT retraction is governed by two limits: the airspeed at which the turbine can be safely stowed and the hydraulic pressure available to drive the retraction mechanism. When the primary power sources are restored, retracting the Ram Air Turbine must occur within a defined airspeed window so that the turbine housing and the retraction hardware aren’t subjected to excess aerodynamic loads, and with enough hydraulic pressure to operate the actuators and latch. 180 knots indicated airspeed represents the upper limit of the safe retraction envelope for the RAT. Pushing beyond that increases dynamic pressure on the RAT and can complicate a clean, reliable stow. The 0.45 value (45 percent) reflects the minimum hydraulic system pressure required to reliably power the retraction actuators and complete the latch/retract sequence. Together, these two numbers specify the safe, certified condition to retract the RAT. Other options pair speeds outside the established retraction window or use hydraulic pressure levels that aren’t approved for reliable stowage, so they don’t meet the tested, safe combination.

Max RAT retraction is governed by two limits: the airspeed at which the turbine can be safely stowed and the hydraulic pressure available to drive the retraction mechanism. When the primary power sources are restored, retracting the Ram Air Turbine must occur within a defined airspeed window so that the turbine housing and the retraction hardware aren’t subjected to excess aerodynamic loads, and with enough hydraulic pressure to operate the actuators and latch.

180 knots indicated airspeed represents the upper limit of the safe retraction envelope for the RAT. Pushing beyond that increases dynamic pressure on the RAT and can complicate a clean, reliable stow. The 0.45 value (45 percent) reflects the minimum hydraulic system pressure required to reliably power the retraction actuators and complete the latch/retract sequence. Together, these two numbers specify the safe, certified condition to retract the RAT.

Other options pair speeds outside the established retraction window or use hydraulic pressure levels that aren’t approved for reliable stowage, so they don’t meet the tested, safe combination.