During a normal engine start, what condition must exist before the Electronic Engine Controls can receive the 115-volt alternating-current supply required for ignition operation?, The engine start switch must be selected to GROUND., The start lever must be moved to IDLE., The ignition selector switch must be selected to BOTH., Under normal electrical configuration, which source supplies the lower ignition exciter and its associated Electronic Engine Control channel?, Alternating-current transfer bus., Direct-current standby bus., Alternating-current standby bus., The normal alternating-current transfer-bus supply to the left ignition system is unavailable. What maintenance provision allows the left ignition system to be powered from the standby source?, Opening the applicable left ignition power-control circuit breaker causes alternating-current standby bus power to be connected to the left exciter., Selecting the ignition selector switch to BOTH automatically transfers the left exciter to alternating-current standby power., Moving the engine start switch to FLIGHT connects the left exciter directly to the standby bus., Why can the Electronic Engine Control channel currently controlling the engine command operation of an igniter electrically associated with the opposite Electronic Engine Control channel?, Each ignition exciter is connected directly to both Electronic Engine Control channels., The Electronic Engine Control channels communicate through the cross-channel data interface, allowing the controlling channel to command ignition through the opposite channel., The Display Processing Computers physically transfer 115-volt alternating-current power between the two ignition exciters., The engine start switch is in AUTO and the engine experiences a rollback. What ignition response should occur without crew selection of another start-switch position?, Only the igniter selected by the ignition selector switch operates., Ignition remains off because AUTO does not provide ignition after engine start., Both igniters operate automatically., The engine start switch is selected to CONTINUOUS while the engine is operating above idle. What additional parameter affects whether the selected igniter or igniters actually spark?, High Pressure Compressor discharge pressure must be below the ignition threshold., N2 must be below the starter cutout speed., The aircraft must be airborne., During an in-flight windmill relight, why is the FLIGHT position fundamentally different from the normal ground-start ignition selection?, The FLIGHT position energizes only the igniter selected by the ignition selector switch., The FLIGHT position engages the starter and inhibits the opposite igniter., The FLIGHT position commands both igniters continuously and does not require starter operation for a windmill start., A ground start develops an overtemperature condition classified by the Electronic Engine Control as a hot start. What ignition-system protection can occur?, The ignition selector switch automatically moves to BOTH., The Electronic Engine Control can stop igniter operation as part of engine damage protection., The ignition exciters reduce their output voltage to approximately half normal value., Why is dedicated cooling airflow routed through the ignition-lead shrouds rather than relying solely on external nacelle airflow?, Low Pressure Compressor discharge air flows through the lead shrouds and exits around the igniter plugs, reducing ignition-lead and igniter temperature in the hot core-compartment environment., The cooling air electrically insulates the ignition leads from the combustor case., The airflow provides the pressure necessary to generate the spark across the igniter electrode., Maintenance is preparing to disconnect an ignition lead from an exciter. Why is simply placing the engine start switch to OFF insufficient as the primary safety precaution?, The start switch does not remove the direct-current supply from the ignition-selector circuit., The ignition exciter can continue generating spark energy indefinitely from internally stored battery power., The ignition system can produce 15,000 to 20,000 volts direct current with an energy output of approximately 14.5 to 16 joules, so the exciters must be positively de-energized before maintenance.

ATA 74

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