wrote: "I have my airspeed sensing switch set a 90 knots, in the gear-up circuit, so that no matter where the gear switch is, it can't raise the gear unless the airspeed is greater than 90 knots. Same on landing. I fi forget to put the gear switch to down, the gear will come down anyway at 90 knots." As I recall Piper used to have an automatic gear extension system on the Arrow. After some accidents caused by the gear coming down before the pilot expected or wanted it to, and sometimes failing to retract because best angle climb speed could be below the gear extension speed, Piper published a service bulletin recommending disabling the automatic gear extension system. Sounds to me like the system was too simple, using one set airspeed below which the gear would extend if it was up, or stay down after takeoff even though the gear switch was in the retracted position. There was an override switch but too often the pilot forgot about it, especially in a tense situation. Tom Gourley --0-1221642193-1264800212=:43237 Content-Type: text/html; charset=us-ascii

All the Arrows I've flown have had the automatic gear extension feature. The system is driven by a pitot probe on the left side of the fuselage. On departure the system sees a higher airspeed than ambient due to the propeller slipstream. On approach this effect is reduced.

Note that the dump valve switch (on the floor between the seats and just aft of the flap handle) can be moved down to dump the gear or up and latched to override the auto down feature. This is used during slow flight/stall practice or when retracting early on departure.

I haven't had any issues with it.

- Kyrilian

On Jan 29, 2010, at 10:31 AM, "Tom Gourley" <tom.gourley@verizon.net> wrote:

"I have my airspeed sensing switch set a 90 knots, in the gear-up circuit, so that no matter where the gear switch is, it can't raise the gear unless the airspeed is greater than 90 knots.

Same on landing. I fi forget to put the gear switch to down, the gear will come down anyway at 90 knots."

As I recall Piper used to have an automatic gear extension system on the Arrow. After some accidents caused by the gear coming down before the pilot expected or wanted it to, and sometimes failing to retract because best angle climb speed could be below the gear extension speed, Piper published a service bulletin recommending disabling the automatic gear extension system. Sounds to me like the system was too simple, using one set airspeed below which the gear would extend if it was up, or stay down after takeoff even though the gear switch was in the retracted position. There was an override switch but too often the pilot forgot about it, especially in a tense situation.

Tom Gourley

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