Bad ignition switch

[flyer]

I got called out to a nearby airport today from a Archer III pilot saying there was smoke in the cockpit. Once I arrived I found this ignition switch to be the culprit. Ive never seen one burn up like that. Needless to say they will be staying the night until I can get a new one installed.

 

[weirdjim]

I got called out to a nearby airport today from a Archer III pilot saying there was smoke in the cockpit. Once I arrived I found this ignition switch to be the culprit. Ive never seen one burn up like that. Needless to say they will be staying the night until I can get a new one installed.

Somebody is going to have to 'splain how a switch that works in a low voltage low current circuit can fail in a manner that a very small amount of power can heat it to the burning point.

I'd look long and hard before replacing the switch as to exactly the failure mode.

Jim

 

[Tom-D]

Somebody is going to have to 'splain how a switch that works in a low voltage low current circuit can fail in a manner that a very small amount of power can heat it to the burning point.

I'd look long and hard before replacing the switch as to exactly the failure mode.

Jim

That switch is a push to start it has 12 volts across the contacts at 10:00.

and when worn it can be turned too far and direct 12 volts to ground, not the starter solinoid

IOW it is not your regular OFF, R, L, Both type of switch, it has a start position too.

 

[flyingcheesehead]

Hmmm. Well, I guess that's why there's an AD on it (76-07-12, IIRC).

 

[Tom-D]

Hmmm. Well, I guess that's why there's an AD on it (76-07-12, IIRC).

How do you know the AD applied to that switch?

 

[flyingcheesehead]

How do you know the AD applied to that switch?

I don't - But I'd say there's a pretty good chance of it.

 

[Tom-D]

I don't - But I'd say there's a pretty good chance of it.

Actually the opposite is true, due to the batch number mentoned in the AD and the White Dot required upgrades to the switch.

You very seldom see the old switches any more. The first indication I note as to if the switch being upgraded is to look for 2 keys on the key ring for the aircraft.

 

[flyingcheesehead]

Actually the opposite is true, due to the batch number mentoned in the AD and the White Dot required upgrades to the switch.

I was thinking more in terms of the fact that this switch actually failed.

You very seldom see the old switches any more.

One of our Archers still has one, the other one was just replaced a year or two ago...

The first indication I note as to if the switch being upgraded is to look for 2 keys on the key ring for the aircraft.

Yep, that's a dead giveaway. I sure wish it was easier to replace the entire set so as to keep the plane on one key. Between our three planes, one Archer is still a one-key bird. The other Archer has two (Ignition, Door/Baggage) and the 182 now has three (Ignition, Door, Baggage). When there's 30 sets of keys to be maintained, that gets to be a pain.

 

[ScottM]

I sure wish it was easier to replace the entire set so as to keep the plane on one key. Between our three planes, one Archer is still a one-key bird. The other Archer has two (Ignition, Door/Baggage) and the 182 now has three (Ignition, Door, Baggage). When there's 30 sets of keys to be maintained, that gets to be a pain.

I have more keys on my airplane key ring than my car one.

Airplane:
1. Door
2. Baggage
3. Mag/ignition
4. Hangar
5. Utility cabinet

Car:
1. car
2. house
3. desk

I too wish there was someway to upgrade all the lock to be a single key. The funny thing is that my baggage door key is the same as my file cabinet at work.

 

[Tom-D]

The best old mag switch........... has a big old lever on it.

 

[gismo]

I have more keys on my airplane key ring than my car one.

Airplane:
1. Door
2. Baggage
3. Mag/ignition
4. Hangar
5. Utility cabinet

Car:
1. car
2. house
3. desk

I too wish there was someway to upgrade all the lock to be a single key. The funny thing is that my baggage door key is the same as my file cabinet at work.

The key to my airplane that I use the most to my airplane is on it's own key ring with a small fob to make it harder to lose.
fortunately all three locks on the plane are keyed the same. The keyswitch in my Baron was never intended to cope with 20 lbs of keys hanging from it, especially in turbulence.

As to your baggage door key, it seems that on most older airplanes any key that easily slides into the lock will open it with a little wiggling. A couple weeks ago I managed to get to the airport in Michigan where my plane was parked without a key to get in. I borrowed a similar looking key from the line crew and saved a trip back to the house.

 

[Dan Thomas]

The best old mag switch........... has a big old lever on it.

Or the one my old Auster had, something like this one:

Your favorite, for those who've never seen one:

Dan