Patent ID: 8892265
Filing Date: 2014-11-18
Classification: B64D

Abstract:
1. A method of deploying a ram air turbine only during flight that comprises the steps of: changing an aeronautical power engagement signal from a negative state to a positive state when at least a predetermined number of aeronautical power generation contactor signals are in an engaged state; changing a ground operations signal from a negative state to a positive state when an external power generation contactor signal is in an engaged state or multiple ones of weight-on-wheel (WOW) signals are in a ground state; changing an airborne signal from a negative state to a positive state when the aeronautical power engagement signal is in a positive state and the ground operations signal remains in a negative state; delaying the airborne signal for a predetermined length of time; changing a latch signal from a negative state to a positive state when the delayed airborne signal changes to the positive state; changing the latch signal from the positive state to the negative state when the ground operations signal changes to the positive state; changing a ram air turbine enablement signal from a negative state to a positive state when any one of the WOW signals is in an air state, all of multiple primary electric bus signals are in a fault state that represents electric potential below a predetermined level and a ram air turbine generator control unit failsafe signal is in a safe state; changing a ram air turbine deployment signal from a negative state to a positive state when the ram air turbine enablement signal and the latch signal are both in the positive state; delaying the ram air turbine deployment signal for a predetermined length of time and holding it for a predetermined length of time; and engaging a ram air deployment solenoid when the delayed and held ram air turbine deployment signal is in the positive state.