Budget has been eaten by getting the engine serviceable again :-(
I know the feeling. “Babysteps” is the word that buzzes in my mind.
altitude preselect is something very neat indeed. Apart, it would have saved the life of one of my friends who fell asleep while on a VS descent without one.
Most (all?) GA autopilots will descend all the way to the ground regardless of the altitude preselect number, IF you forget to press ARM, or if you set meaningless parameters (e.g. currently at 4900ft, set 5000ft on the preselect, and set minus 500fpm).
Peter wrote:
Most (all?) GA autopilots will descend all the way to the ground regardless of the altitude preselect number, IF you forget to press ARM
The quite rare STEC 1500 we have fortunately does not but the KFC150 we had before did.
or if you set meaningless parameters (e.g. currently at 4900ft, set 5000ft on the preselect, and set minus 500fpm).
The same STEC 1500 does not want to go into a descent if you set an altitude above the current altitude, but also quite a rare feature.
Peter wrote:
Most (all?) GA autopilots will descend all the way to the ground regardless of the altitude preselect number, IF you forget to press ARM, or if you set meaningless parameters (e.g. currently at 4900ft, set 5000ft on the preselect, and set minus 500fpm).
Not only GA AP’s do that. I recall an airline which had the unfortunate procedure to enter GA altitude once on final descent on non precision approaches flown on VS mode. The result unfortunately was an accident with close to 30 people killed.
Altitude Preselect only makes sense if used properly, like any AP mode and that includes to arm it EVERY time you change the setting. And obviously I am an advocate of setting the MDA on non precision approaches and arming it. It’s a question of procedure and getting used to do these things.
The logic of most altitude preselects for GA planes is not “let’s fly to this altitude” but “whatever I currently do, whenever I by chance happen to cross this altitude I’ll bring vertical speed to zero”.
That’s exactly the difference between an altitude preselect and a lvl-change mode of an autopilot.
(Needless to say: Both do not work if not armed/activated correctly…"
Exactly right 
but not many people know that.
The other strange thing is that – on the King ones – twiddling the preselect number activates the ARM mode, but there are ways to deselect the ARM accidentally.
do avionics installers give credit for the equipment they remove, eg replacing a 430W with a GTN750 ?
Or do you have to sell it yourself ?
I’ve seen both.
The problem is that in Europe you cannot sell used avionics for any official installation, unless you somehow get an EASA-1 form issued for it. You can sell it to an N-reg owner, or on US Ebay. I have sold a ton of stuff on US Ebay but as usual this is a fair bit of work (photos, a long description, the usual stuff to get a good sale on Ebay).
Malibuflyer wrote:
The logic of most altitude preselects for GA planes is not “let’s fly to this altitude” but “whatever I currently do, whenever I by chance happen to cross this altitude I’ll bring vertical speed to zero”.That’s exactly the difference between an altitude preselect and a lvl-change mode of an autopilot.
Even larger aircraft autopilots work that way. The preselect is only relevant if you move towards it. FLC mode on COLLINS pro line will descend you at a given airspeed until the ground if the preselect is above the altitude at which the descent started.
Peter wrote:
The problem is that in Europe you cannot sell used avionics for any official installation, unless you somehow get an EASA-1 form issued for it.
Done that, never was a problem to get an EASA-1 for stuff they took out of my plane if they got to install the replacement. In one case, they made an offer themselves which I gladly accepted.
Mooney_Driver wrote:
And obviously I am an advocate of setting the MDA on non precision approaches and arming it.
You don’t fly CDFA? Or if you do, what’s the difference from an ILS/LPV?
