Backup for dropping the gear

In a previous article, "Peter Duniho" said:
And actually, while I haven't flown the Pipers you're referring to, my
understanding is that the gear extension was based on airspeed, not engine
power. Your comment about the behavior of such systems in icing conditions

The POH for the Lance isn't 100% clear on this, but my understanding is
that with the emergency gear extension, the gear will come down if you go
below a certain manifold pressure at one speed, or will come down
regardless of the manifold pressure at a lower speed.

The POH says "Some aircraft also incorporate a pressure sensing device in
the system which lowers the gear regardless of gear selector position,
depending upon airspeed and engine power (propellor slipstream). Gear
extension is designed to occur, even if the selector is in the up
position, at airspeeds below approximately 103 KIAS with power off. The
extension speeds will vary from approximately 91 kts to approximately 103
KIAS depending on power settings and altitude."

Actually, reading that again, it's possible that what is happening isn't
that it comes on at a lower speed if you have power on, but that the
propellor slipstream holds the gear up against the springs if you have
power on.

Sometimes I learn more answering other people's questions than I do
getting answers to my own.

--
Paul Tomblin http://xcski.com/blogs/pt/
If you're not part of the solution, you're part of the precipitate.