I *think* Ive sussed a wee issue. whenever I disengage the autopilot on the 748, the props ALWAYS feather, and at some times, Jennies go off line too ( I think ths started happening around my last post on the 748) - latest flight was from Penticton to PAYA - I disengaged AP at 1500 feet on the approach, and immediately had to restart jennies and sort the props. Any ideas guys? This has *certainly* not been any kind of issue until quite recently......
I've never had this problem myself so is perhaps self inflicted? Are you starting from a default aircraft first before you switch? If you're starting from a '748 saved flight then that may cause a few problems.
If this problem has only started 'recently' you might have to rack your brains and try and think what changes you have made before this problem started for you. Have you been messing with any assignments/keystrokes in FSUIPC which might be conflicting with your fs assignments ?
Yup.. this most definately ISN'T an issue with the 748 'itself'.. more an issue with something else. I'm sure you realise that we wouldn't have let the 748 go into the big wild world with the props feathering when the AP is disengaged.. not that any of us had ever seen this happen anyway! ;-)
Just curious, if you are in fact able to control the engines rpm with the throttle levers manually,
when your auto pilot functions Are turned on.
I have had props feather when I pull down on the levers to quickly And have seen the genies kick off as well.
Just wondering if kicking off the auto pilot is de-throttling the engines too quickly.
Because the lever position is at the minimum manual setting….something like that maybe?
Yup - I was thinking that, and I have caused that myself with being too quick with the throttle - but - I only use AP for height and heading - after takeoff, I use f2/3 for the throttles - in a standard descent, I tap F2 to get the speed down to about 180kts (ish) - and once I'm through a given height, I disconnect the AP to land manually - the point being - the throttles are always controlled manually...... but something (and I've not altered any settings that I know about) *is* creating an RPM surge when I power the AP down - yet, when I disengage, the aircraft is trimmed and at desired speed..... so why is it getting effected with the AP switch?..... time to check something else.... :think:
Props feathered once out of two attemps at disengaging AP. Now, joystick throttle is normally about 90% - all other adjustments (except final approach) are using f2/3. If set around 75/80%, this seems to be enough to cause a spike when the throttle is moved (IE throttle is moved back, but RPM jumps to intitial setting on joystick then drops back.) Depending on speed and RPM, seems to be the reason I'm getting this.....
Time for an update to my standard ops in this bird methinks
Don't know what type of joystick you're using Jim, certainly mine wouldn't allow keyboard, or panel lever adjustments, to be effective unless the joystick lever was fully closed or fully open.
Assuming yours is allowing this, and you're throttled back below the recommended minimum in flight power of about 70/80 psi, theres a possibility that when you disengage the AP, the joystick throttle setting is implemented instantly rather than that which you set with the keyboard strokes. This instant change would cause the autofeather circuit to operate in the same way that it does on the ground if the throttles are advanced too quickly before sufficient power is registered, ie at least 50 psi. :think:
