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Dodgy ignition / magneto switch, and replacing with an Electroair push-button assembly

Mine has done 20 years and when starting (in freezing temps) I found that the starter got energised only if the key was not turned too far.

Also the little STARTER ON light was not ON when the starter was not on.

It may have been my technique, or a worn key (is that possible?), or maybe I wasn’t pushing hard enough. I did reproduce it after I landed (3hr flight). On later flights, with my son flying and using his own key, it has been fine. But I ought to order a replacement switch. It is TCM 10-357210-1.

It is an absolute bastard to get to the back of it. Does anyone know how to extract it? The black bezel has no flats, so the whole thing probably unscrews from behind the panel.

£460 ex stock from Saywell

Administrator
Shoreham EGKA, United Kingdom

Ive not worked on one of those exact ones, nor ones in an aircraft, but have fitted some similar ones in boats, plant machinery and industrial control cabinets.
Most likely the hole is not fully circular ( to resist it turning), and there will be a ‘back-nut’ (threaded locking ring) against the rear of the panel face. Thus meaning you need to disconnect it and pull it out towards you.

Last Edited by GA_Pete at 20 Jan 16:35
United Kingdom

Remove it and replace with 2x on-off switches for the mags and 1x momentary push-to-make switch for the starter. Wire the latter via a hidden switch under the seat for security, although probably unnecessary if you don’t leave the doors unlocked.

:-)

What @GA_Pete said about removing it. There will be something screwed on the back holding it all on the panel.

Last Edited by Graham at 20 Jan 19:59
EGLM & EGTN

Agree with @Graham. Get one of these, price diff would pay for part of additional install cost.
Electroair Switch Panel

LSZK, Switzerland

They look nice. Very nice.
I’m quite tempted myself.
I do wonder if it would increase my likelihood of deparure with keys still hanging from the luggage comp lock?

United Kingdom

Yes – very nice.

On FAA, Minor mod?

What if the button is pressed during flight? Does it smash up the flywheel and the starter and loads of other bits?

Administrator
Shoreham EGKA, United Kingdom

On FAA, yes, minor mod. I have it on my Cessna 172.

Activation in flight question could be asked about rotary switch too. Sure, one could argue likelihood, but the button really needs to be deliberately pressed. It is relatively well protected. With all the issues related to rotaty switches (including thread subject), advantages seem to clearly outweigh. This type of config is more common in higher performance aircraft, especially twins. Wonder why?

LSZK, Switzerland

chflyer wrote:

This type of config is more common in higher performance aircraft, especially twins. Wonder why?

Because there are only so many reasonable positions on a key switch. You would need two separate key switches – one for each engine.

ESKC (Uppsala/Sundbro), Sweden

What would happen if the starter got energised during flight?

Looking at where this thing would be located, it could get kicked…

Administrator
Shoreham EGKA, United Kingdom

What would happen if the starter got energised during flight?

No different to what if still on the ground with that engine running
A few bruised or eroded teeth, if done on the bigger engines with a starter flywheel… small Contis, as an example, might have the starter installed on the accessory gear box, and pushing a starter switch whilst the engine is running is definitely not a good idea…

Dan
ain't the Destination, but the Journey
LSZF, Switzerland
22 Posts
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