Fault flag driver

An electromechanical indicator for receiving a digital fault code indicative of the occurrence of a fault in an aircraft, comprising:

• (a) latching means for receiving and latching the fault code;
• (b) driving means coupled to the latching means for receiving and amplifying the latched fault code and for presenting the amplified fault code to an indicator, the indicator comprising:
• (i) a plurality of electromechanical indicators, each responsive to a respective bit of the fault code and each having:
• (A) two display states and
• (B) biasing means for inhibiting change of the indicator from its present state;
• (c) enabling means including:
• (i) a first transistor through which electric current flows along a common supply line to the electromechanical indicators,
• (ii) a second transistor coupled to the first transistor for turning off and on the first transistor, and
• (iii) a third transistor for supplying current to a first relay coil;
• (d) control means including:
• (i) the relay coil of (c) (iii);
• (ii) a pair of relay reeds magnetically toggled by the first relay coil and by a second relay coil, the relay reeds being pulled into a first position and latched by the passage of current through the first relay coil, the first position functioning to turn off the first transistor;
• and
• (iii) a second relay coil for driving the pair of reeds into, and latching them in, a second position by passage of current through the second relay coil, thereby allowing the first transistor to be turned on;
• and
• (e) resetting means coupled to the electromechanical indicators and to the second relay coil for:
• (i) placing all of the indicators into a first, initialized state and
• (ii) driving the second reed into the state wherein the first transistor is able to be turned on.