Altmatic A/P

[Jamair]

OK all youse salty old Piper Pilots - working on the theory that the only 'dumb' questions are the ones you don't ask:

Does anyone have encyclopaedic knowledge of the 'ALTMATIC' autopilot as fitted to PA23 and certain other Piper Twins? It is branded as 'Piper' but I suspect it is actually a Century system.

Better yet, who has a manual for the thing?

About all I can get it to do is hold a heading on a DG bug; there is an ALT HOLD feature, a PITCH feature, a PITCH TRIM and a ROLL feature. The PITCH feature include a knob and a height selector drum, but engaging it at any altitude just shoots the aeroplane straight up, regardless of what is set on the selector. The PITCH TRIM bubble doesn't seem to do anything when the PITCH TRIM adjuster is moved. The ALT HOLD doesn't.

There is a source selector separate from the main panel that has NAV-OMNI-HDG-LOC-REV; so what's the difference between a NAV (VOR CDI) and an OMNI?

If there is anyone with the hot goss on this bit of kit, please get back to me........before I spit the dummy and rip it out in favour of a new digital mega-buck shiny S-TEC thingy.........It may be that the thing is knackered, but I would hate to replace it only to find out later that I just didn't know how to work it..........

(Adopts patient, hope-filled waiting attitude......)
:cool:

[Dale Harris]

Get the S-Tec.........I'm only half kidding........... It is a century by another name, but getting a manual might be hard. Although the aircraft POH should have some info. (And don't tell me you don't have that please.) The only ones I have access to are the Altimatic 3c and the 5. The operation manuals I have are part of the POH/Flight manual, so, no you can't have them.........!!!!!!! Like I said, get the S-Tec. MUCH better!!!!!!!

[hoss]

Dale,

Check your inbox.

Best Wishes, hoss :)

[Chimbu chuckles]

If it's a Century by another name then it may have the same Amphenel plugs as the Century 111 etc.

You'll remember how mine was working ex Roma...many similarities with what you're experiencing but mine does hold altitude....until it won't then it trims nose down.

I will be having mine looked at closer at the next 100 hrly and word I have from several sources is that the Amphenel (sp?) plugs are the main culprit in most C3 problems. Apparently their design is such that they get lose and need to be unplugged and the little 'tangs' inside bent back into position for a tight fit...then when they are clean and tight they are often tie rapped so they stay that way!!

A mate who used to fly my Bonanza, and who is an ex QF Instrument/Electrical Lame and has worked on Century A/Ps a lot says check the plugs before anything else!!

In fact give us a ring and I'll put you on to him!!


Chuck.

[Jamair]

Thanks Chuck; as always a font of knowledge.......I should have remembered your AP and our 'prompt' departure from cruise height - is the ding is still in the Bonzas roof over the RH seat?

I'll give you a call within the next coupla wks - I'll be down to RED in the bird & we can compare notes on JPIs... speaking of which, the link to John Deakins articles on your 'Piston Engines etc' thread doesn't work since AVWEB changed formats.

Ah for the good ol days, when the most hight tech AP was a bungy cord tied to the RH column.......cheap to repair too, but a little awkward to couple to the ILS :D