- in case of failure of automatic starter valve actuation device, the FADEC logic is compatible with manual actuation of the start valve.

 (b) Start interruption Interruption of automatic start is possible by selection of the ENG MASTER switch to the OFF position. That action initiates :

 - direct closure of the HP fuel shut off valve

 - starter shutoff valve closure via FADEC

 - ignition exciters OFF.

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ECES E F 『 E C F M E E E E 56-5B E E E (c) Start abort

 1 On ground
_ Start abort by the FADEC is automatic below 50 percent N2 in case of detected incident such as :
 - hot start

 - no ignition

 - start stall.

 - starter time exceedance The FADEC also provides the necessary information to the cockpit.

 2 In flight
_ The FADEC provides the same monitor as on ground with fault announcement but the start abort is manual only.
 (3) Alternative Start
 (a) Engine starting logic The FADEC has the capability to perform alternative start, after reception of the signal "Man start". The FADEC operates with the following sequence :
 - the ENG/MODE selector switch being to IGN/START position, the FADEC opens the starter shutoff valve when it receives the "Man start" signal

 - when the ENG MASTER switch is switched to ON, the FADEC opens the HP fuel shut off valve and energizes the ignition exciter.

 - when N2 reaches 50 percent rpm the FADEC closes the starter shutoff valve and de-energizes the ignition exciter.

 - then the FADEC controls the fuel according to the start fuel schedule

 NOTE : for airstart, when alternative start is selected, the
____ FADEC always command a starter assisted airstart in alternate mode the FADEC performs the same monitoring than in automatic start, and provides the same warning indications but the starting interruption is under manual control.
 (b) Start interruption Interruption of alternative start is possible by :
 - releasing the ENG/MAN START pushbutton switch if the ENG MASTER switch is OFF

 - selection of the ENG MASTER switch back to OFF if it is ON.

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ECES E E 56-5B E E E (4) Engine Shut off If the ENG MASTER switch is set to the OFF position, an engine off signal is sent to the FADEC. The HP fuel shut-off valve is directly closed. The FADEC does not have the capability to turn fuel off except during automatic ground start. The direct signal from cockpit has always the priority over the FADEC for shutting the engine down even if the FADEC commands a HP fuel shut off valve open.

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 F. Thrust reverser control
 (1) ECU control logic The ECU thrust reverser logic has four basic functions. These functions are invoked in response to the flight/ground status, the engine status, the calculated Mach number, the throttle control lever angle value and the thrust reverser doors position. These functions are:

 - the position hold function assures that the thrust reverser does not move when the aircraft is on the ground with the engine not running (when not in menu mode T/R test)

 - the reverse inhibit function ensures that in flight with the engine not running, the TRPV is commanded closed and idle automatically commanded if TLA is set in reverse area.

 - the forward thrust function commands the thrust reverser doors to restow if at least one door is detected to be unstowed and the aircraft is on ground. This function ensures also that engine power will be limited to idle, overriding the throttle control lever position when at least one door is unstowed (or in determined door position) and the thrust reverser system is pressurized or if 4 doors are detected unstowed

 - the reverse thrust function will deploy the thrust reverser doors if the aircraft is validated on ground with the engine running and has been commanded through the thrust reverser control lever

 (2) EIU directional control valve supply The EIU switches aircraft 28VDC to the directional control valve solenoid when thrust reverser control lever is in reverse area. This information is independent of the one provided to the ECU. The ECU has its own resolver for the thrust reverser control lever position acquisition.

 (3) Design precaution To deploy the thrust reverser doors, three commands are necessary:

 - control of isolation control valve (TRPV) from ECU, Directional Control Valve (TRDV) from ECU

 - control of TRDV supply from EIU.

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