A320 Eng. mode selector

[squawkident.]

Hello,

My company has recently aligned our SOPS to that of Airbus and I have a question regarding the eng. mode selector switch.

Both the Before T/O Below the line and approach checklists have a challenge and response for "engine mode selector" / "on" or "normal".

My question is really what is the significance of checking this switch position just before T/O and during the approach, not landing?

Is it a reminder to "firewall" the engines in case of heavy precipitation? I would have thought that during T/O the engines are up at high power anyways so wouldn't need the extra? Or am I completely barking up the wrong tree.

[vilas]

squawkident
Each engine manufacturer has his own recommendations on use of ignition, other than those the use of ignition is discouraged since there is effective autorelight function. It has nothing to do with firewalling. The checklist just confirms that the mode selector is in the desired mode as you planned.

[*Lancer*]

PRO-NOR-SOP-11: Select IGN START, if heavy rain or severe turbulence is expected after takeoff.

In IGN AUTO, continuous ignition will automatically disengage when you move the thrust levers back from the T/O thrust setting (if NAI is OFF).

[squawkident.]

Thanks guys.

So basically its a check before T/O if departing into heavy precipitation to switch ignition on (if NAI is off).

So why the check again during approach checklist? Surely if you need it in flight then you would just turn it on, regardless of phase of flight (again if NAI is off).
Whats significant about the approach checklist?

Thanks

[vilas]

squawk
Basically ignition requirements are laid down for any phase of flight but before takeoff because it is critical phase and during approach since the thrust will be low just as a reminder that you have given it the due consideration.

[squawkident.]

aahh I see.

Thank you villas

[390cruise]

NAI

Are we a little out of date ?

I believe most operators have modified their Aircraft so that selection of Engine anti ice no longer causes ignition to operate.(319/320/321CFM)

[*Lancer*]

My operator uses IAE and it's still the default.

NAI and IGN should be considered separately anyway

[Stone_cold]

390 .

Not sure 100 % about the CFM , and whether you have actually flown for and can speak for "most" operators ", but it would be prudent to understand that perhaps the individuals here may not have this mod you speak of . Secondly , for the IAE's this "Mod" only removed the indication from the ECAM memo . the system continues to function as advertised . "Ignition On "

[vilas]

390 cruise
CFM and CAE have different conditions for automatic ignition. CFM engine ignition comes on only for flame out detected, EIU failure and ignition delay during start. But IAE there are more situations when it comes on like: Engine Anti ice, Max thrust, Flex thrust, EIU data failed, Approach idle, Inflight unscheduled sub idle or surge, Engine master lever cycled from ON to OFF and ON again.

[Natstrackalpha]

Why the talk of A.Ice? We were talking about the mode selector switch.


I forget - but, strange not nice things happens if you line up and takeoff with mode selector switch in IGN - I forgot what that is.


But also - this would give you cont ign. which might be desirable in a torrential rainstorm and crosswind to the max . . limits, almost.


Now, what was it that goes bump if you leave the mode selector switch on during T/O . . . . . A/T . . . speed . . . ? bleeds . . .?


. . .I remember - you want get a flight controls page if you leave the mode selector in IGN, until you put it back to norm.