hamil

Hi everyone,
A friend of mine asked me but I have no idea so could someone tell me why the stabilizer trim position indicator on the pedestal of the Piper Navajo Chieftain has that kind of irregular format (a mix of wide and thin black band)? In average how to set a proper position for takeoff?
Thanks

bobrun

I went to the Flight Safety training for the PA31 chieftain several years ago, and that was one of my question as well.......however, no one over there new at that time why it was designed that way, and the AFM doesn't give a clue either....

Icebreaker

hamil,
I've about 4,000 hours on Chieftain (albiet not for a few years now). This trim setting would be similar on Navajo.

We would set trim 3 and a half revolutions back from full nose down position. If the pax we sitting more forward - another half a revolution aft and vice versa.
Used to work fine - those trim position indicators were usually pretty dodgy at the best of times.

GearDoor

I agree with icebreaker, but I always used three full cranks back from full nose down. Would adjust either way up to about 3/4 of a turn based on load distribution. Trim indicators are usless.

Centaurus

Trim indicators in the Chieftain/Navajo are fine if maintained properly. Trouble is that from bitter experience many GA pilot's are reluctant to write up defects in the maintenance release for fear of being accused of making waves and getting the boot. Thus defects remain un-rectified and the particular aircraft eventually gets a bad name.

Tinstaafl

I suspect that the slightly wider part of the take-off trim region marks the 'trim neutral' position ie is in trail with the elevator. I'll have a look next time I fly our one.

morning mungrel

The wider section at the top of the band would be for the normal takeoff trim position wouldn't it? Similar to the "green" range used by other manufacturers. The mid point I think is the thin mark about mid way or slightly off the mid point of the indicator, ie. neutral.

Icebreaker

Centaurus,

doesn't matter how well they are maintained, setting the trim using the 3 turns back is a no-brainer which can be done with confidence whilst taxing, especially in night ops/poor visibility etc. Then you can verify the setting with a quick glance to the indicator rather than take your eyes off where you're taxiing. Makes life easier and it's foolproof.

morning mungrel

Just curious Icebreaker..... While I use the three turn thing myself, I'm wondering why you would doing said checks while moving in lowvis/night anyway? I am quite aware that a few people do, just don't understand why.............