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6th Jul 2018, 16:47

#3 (permalink)

Skyjob

Join Date: Jan 2000

Location: FL410

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Quote:

Originally Posted by FlyingStone

737 can depart with R igniter U/S as per the MEL, whereas then the L igniter has to be wired to the AC standby bus.

I think your statement is incorrect in the sense that:

ONE IGNITOR for each engine must to be powered by DC battery power through the AC Standby Bus;
if the RIGHT IGNITOR is not working, prior to departure aircraft maintenance procedures MUST be applied to ensure LEFT IGNITOR is powered by AC Standby Bus;
if the LEFT IGNITOR is not working, prior to dispatch no actions are required provided RIGHT IGNITOR works properly, to ensure operational integrity in this case the switch is left in the BOTH position (to avoid using LEFT).

As per FCOM Start Switch to FLT "provides ignition to both igniters when engine start lever is in IDLE", and in some cases a power source is still available through APU, eg on ETOPS configured flights. Therefore it would be unthinkable to init yourself to battery ignition by selecting RIGHT.

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