Three times over the past two weeks (once on a long sea crossing) my starter warning light came on in flight – PA28-181. It is exactly the same as above.
Once the light came on dimly and twice at normal brightness. In all cases a short press of the “press to test” indicator light cleared the issue.
My understanding is this light is connected to the coil of the solenoid and there was no indication that the starter had engaged in flight. I am fairly sure can tell from the voltage on the EDM700 and no adverse noises and no indications after the flight.
Has anybody ever had these warning lights randomly operate? Perhaps it just needs switch cleaner as it seems to be connecting to the +12 volt “test” wire.
At least the way ours is wired it can’t come on unless the starter solenoid coil is getting 12v. If yours is the same it’s quite possible that the ‘press to test’ is turning it on – perhaps something in the press to test mechanism has vibrated loose (and it extinguishing when you press to test would seem to suggest this).
I thought ours was coming on erroneously until I looked at the assembly, ours is different and is basically just a small light bulb behind a red lens, but there’s nothing but the bulb holder behind it and at the right angle sunlight could shine through where the aileron cable runs up out from the side of the panel and onto the back of the lens. I don’t think that can happen with your style of assembly though.
Archer-181 wrote:
My understanding is this light is connected to the coil of the solenoid
This isn’t how it’s meant to be wired. The activating supply to the lamp should come from the heavy-duty OUTPUT terminal of the starter solenoid, via a low-rated fuse. This is to ensure that if the contacts get welded together, a warning is provided even if the solenoid isn’t being provided with a coil-energising supply.
The system was first introduced by UK CAA as Airworthiness 33 and subsequently became CAP747 GR1, but was later dropped as we finally harmonised retained UK rules with EASA.
Years ago I had to rewire the battery cables on a Chipmunk when the start contactor (wrong type for the aircraft) randomly engaged and got stuck during aerobatics (I guess positive G overcame the plunger return spring tension). The first the pilot knew was loads of smoke in the cockpit as the battery cables overheated! He had a start warning light but it was fitted with a dimmable cap which had been left in night mode!
Thank you so much @wigglyamp . That explains the in-line fuse nearby! I am almost sure it is the “press to test” function on the warning light which has become intermittent. My photo shows the type of light but mine presumably has 3 x terminals. 0 Volts/ + 12v (permanent for the test function) and + 12v connected to the heavy duty output as stated above.
Has anybody experienced any of these warning lights randomly operating? It was all very worrying!
