"Roy Smith" wrote in message
...
I had an interesting experience the other day.

I was with a student in one of our club Arrows. We put the gear down
and got green lights for the 2 mains, but not for the nose.

What would you have done? Would you have cycled the gear hoping to fix
the problem, or would you have accepted the possible unlocked nosegear
in exchange for the known locked mains?

Roy,

I don't think you could have harmed anything further by cycling the gear.
Knowing how the PA28 gear system works, you can always free-fall them all
into position should you have a complete hydraulic failure.

Chances are, there was an out of rig microswitch on the nose gear, sending a
signal to the hydraulic power pack that the nose gear was not down and
locked. When the power pack received this signal, it re-energized for a
second until the microswitch was closed. When it de-energized, the
microswitch re-opened, sending the signal back to the power pack and the
vicious cycle repeated itself over and over again ... hence the cycling of
the 'in transit' (aka 'pump on') light. You could have verified all of this
by looking for a spike on the ammeter as the electric motor in the hydraulic
power pack cycled off and on.

In any case, the green light would have never illuminated at all for the
nose if it had not reached the locked position. Once it reaches the locked
position, it is not unlocking unless you select the gear up.

In either case, you were safe. It was simply an indication issue brought on
by an out of rig switch. Mx should have detected this and fixed it
otherwise it will likely occur again.

-RH