[Amps] time to death...

[Bill, W6WRT]

ORIGINAL MESSAGE:

On Thu, 11 Nov 2010 11:11:02 -0800 (GMT-08:00), Colin Lamb
<k7fm at teleport.com> wrote:

>
>I suggested installing a microswitch and light on the dash - which he did last year.  Except it was a Radio Shack led (not very bright). 

REPLY:

There is a lesson in fail safe design here. 

There should be two LEDs - green for gear down and red for gear up.
Having only one LED is asking for trouble. Suppose the LED burns out or
the circuitry fails? Is that the same as "OFF"?  And what if a tired or
distracted pilot momentarily can't remember whether the unlit condition
means gear down or gear up or vice versa?

With two LEDs the pilot knows either one or the other must always be on.
If both are off or both are on, he knows the warning circuitry has
failed and can take appropriate action. 

73, Bill W6WRT