After take off I would engage the Prop Synch and leave in on during climb, cruise, descent and approach? Is this correct, I have looked through the checklist and AOM and can see no reference during flight that once it's engaged that you would ever disengage it, is this correct? Im not to familiar with props and for some reason its in my head that the prop synch should be off at some phase, I just want to make sure I did not miss anything in the manuals.

After take off I would engage the Prop Synch and leave in on during climb, cruise, descent and approach? Is this correct, I have looked through the checklist and AOM and can see no reference during flight that once it's engaged that you would ever disengage it, is this correct? Im not to familiar with props and for some reason its in my head that the prop synch should be off at some phase, I just want to make sure I did not miss anything in the manuals.

Ian, the Prop Sync must be off for takeoff an landing, and it won't do you much good on descent in the terminal area when you're makign a lot of power changes.The system needs to be off in order to ensure that a failure of the "master" engine doesn't adversely affect the good engine. Even though the Prop Sync has very limited authority to trim fuel flow to the slave engine, you wouldn't want any trimming of fuel flow in case of an engine failure. I don't know whether this system uses the same components as the TTL to bypass fuel (I doubt it), but you wouldn't want one system trimming fuel while the APR is simultaneously trying to increase FF.I'm not sure why it's not in the actual checklist, but try searching through the "Flows", and you'll probably find it there.Regards,Nick

It's in Ch086:5 of the AOM.The implication is that the system will turn itself off when you command an RPM change (e.g. when moving to FLIGHT during final approach). It doesn't say whether the switch should reset itself at this point. The manual also states "The PROP SYNCRO switch must be OFF for take-off and landing".I, myself, turn the synchrophaser off when moving the conditon levers forward prior to landing. But as you say, the normal ops don't include this action in any flows.It'd be nice to hear if someone with real JS41 time had any info on this.Cheers,

I'll check the AOM again I must have missed it. Thanks for the help on this one guys appreciate it.