TBM 930 Ignition auto or on

I cant find it in the TBM 930 POM.

Whats the diffrerence between auto and on?

You switch it on during engine start and then going to Auto during normal operation.
A turbine don’t need an ignition during normal operation, but under certain conditions I could be possible, that an engine flameout could occur, and then the engine ignition came up and prevent the flameout.
So, that’s how I understood, years ago, when an RJ85 Captain told me about it.


Nica many thanks!

This is how it works for many airliners out there, but there is no auto-ignition like that in the TBM.
Auto-ignition in the TBM automatically turns on the ignition once you place the starter switch in the on position. During bad weather or any other curcumstances where you may want the ignition running, you must turn it on manually.

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Check their website for the official manuals: tbm.aero/media/downloads/

It’s basically the same with all jet engines, regardless if it’s the TBM or an airliner.
The igniters are on as long as the starter is operating. (auto ignition)
In all other cases you need to turn them on manually.

The only difference is that on some airlines the auto-ignition is also active if e.g. the slats are extended and/or e.g. the engine anti-ice is being turned on.

Ok, well than its a little different than i remember and it doesn’t really make sense for me this way, but i never read the manual for that plane.
In that case i would expect, that there are just the 2 positions on and off. For which reason should “Auto” be, if its just for the short phase of starting the engine?
Guess i will read the manual to understand this, before i’m going mad. :joy:

Honestly? Because it’s a French aircraft.

The trim sound on e.g. the Falcon 50 is another example for a French design.

Or the different slat/flap positions with the same lever position on the A320.


:rofl: :rofl: made my day, dude.



But it‘s not only because it‘s french, other aircraft designers made strange decisions too…

„Dial a flap“ for example is american.

Or forgetting to add a whiskey compass and then mounting it behind the pilots and using mirrors to read it. Same company :smiley: use 50ish knobs for cockpit lighting. :smiley:

In the 777 almost everything is set to auto and still you turn „on“ for example the engine anti ice manually, 747 too I was told.

Some aircraft have de-ice systems and some have anti-ice. And some call it anti-ice while it‘s actually a de-ice. You need to read the manual and become comfortable with each and every model ^^

Where have you got this ‘info’ from?
AFAIK this location had bee choosen to reduce the interference from the electrical items in the vicinity of the instrument panel.

That’s the way it is in most jets. Selecting engine anti-ice is the pilots decision, especially since ice-detectors usually aren’t reliable enough.

Do you have an example?

take it with a blinking eye :smiley:

And so a sole “auto” position isn’t desired anyway, is it?

I don’t understand the last sentence?

I meant that it’s desired to have a “on” position for those systems that have an auto function like for example the anti ice system.

Embraer has the same regarding flap / slat position, there are two lever positions giving the exact same slat / flap position, its only purpose is a system logic, one is selected for take-off, the other for go-around :sweat_smile:.