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ontheair

some questions

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1) is the TOGA button located on the left throttle modelled or not ? Not sure about that2) after take-off c/l last item : Prop Sync ON. Sounds strange to me, why after t/o and not before ?3) unfeather switch inop with GPU connected : what can I do to make it available ?Merci

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1) Yes it is modelled but not like in a aircraft with auto throttle. It just makes the FD go in Go Around mode. You have to push the throttle forward by yourself.2) Because the props de-synch if you change the rpm. So synchronising should be done after you set reduced rpm (96-98). (Manual: 8-6-5)3) Never heard about this. Why do you think it is inop?

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Thanks CapP"3) Never heard about this. Why do you think it is inop?"Because it sometimes happens (random issue ?) that the blades does not move at all when the unfeather pump switch is activated left or right + throttles levers moved to the full reverse position + condition levers set to taxi + GPU connectedIs that unfeather pump electric only or hydraulic ?

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Unfeather pump is electric so without batteries or gpu it won't work.

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Ya I don't understand why the unfeather pump is not working for you...I'll give it a try this afternoon, but I don't thing i've ever observed this behaviour.The prop sync is off for take-off as the sudden changes in all sorts of engine speed and such or too much for the sync unit. I believe it matches more than RPM it also matches phase as well...so in the case of a engine failure it would cause some really wonky things I believe during take-off.I have to read the manual here and give you a better explanation. It's always been a no-no on all multi engine types to keep prop-sync off and such..never really thought why.

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It's always been a no-no on all multi engine types to keep prop-sync off and such..never really thought why.
Is it really? I always thought it was more of an annoyance issue with the props being out of phase than anything. I could be very wrong on that, though.

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Ha just read what I typed. To clarify...it's always been a no-no to keep the prop-sync on during take off and landing opsLemme explain better.It's a no no because the prop synchrophaser; which acts on the propeller governor through a slave and master propeller system, adjusts the oil flow to the propeller hub every so slightly, awith little adjustments of propeller blade angle, in order to not only match propeller RPM, but also 'phase'; that is, the propellers are all in the same 'position' at a given time.During take-off and landing, we want our propellers to be in the correct fine position (on PT6's prime blade angle - TPE331 - flight idle). This give's us the greatest power for propeller(PT6)/engine(TPE331) speed possible. During these 'critical' flight phases, we could care less about annoyances. We want to get off the ground. On the go-around we want to get out of the way with the greatest power.One propeller is trying to match the other; the 'master' and 'slave'. This is the danger: What if right after rotation, we get an engine failure on the master engine? The slave would try and match it during this already dangerous single-engine-fully-loaded-obstacle-clearance take-off! :(.Of course, the syncrophaser system doesn't really have the mechanical or electrical authority to feather the slave engine if the master fails, but just that momentary blip when it does try and match it could be catastrophic in a go-around or single engine climb scenario.This is all coming off the top of my head here...don't have any manuals or text's infront of me at the moment, but it's what I remember.A little trick I learned from some King Air drivers. Engage the prop sync for a quick bit after you adjust your propellers to max speed/fine pitch entering the approach phase. Then, as you commence your approach disengage it through your normal checklists. If your approach thrust and everything has been set correctly, and you don't need to make too many adjustments to power levers...your props should stay relatively in phase throughout the approach and landing phase.It has been left on accidentally many times before through, and besides being a little hard on the older style electro-mechanical prop-sync units (they don't know what's going on when you go into reverse! haha) It isn't the end of the world.

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"Ya I don't understand why the unfeather pump is not working for you..." It works most of the time but does not from time to timeThanks for the explanation provided related to prop sync.IMHO something important is missing in the J41 normal c/l : the prop sync is set to ON after the cond levers have been set to 98%/96% (see after t/o c/l) and it stay ON till the very end of the flight. The descent and approach c/l should be modified to include "Prop sync OFF" Wrong or right ?

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Regarding Prop Sync, the PMDG_J41_ AOM says in Chapter 8.6 page 5 of Engines and Propellers : The PROP SYNCRO switch must be OFF for take-off and landing.So, that's what needs to be done during the landing check. I have amended my printed check list to remind me.

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