That’s just one performance profile.
1000 fpm is not great for passenger comfort. But obviously doable.
146 KIAS is actually the prior to or during descent engine (edit: instrument) failure procedure. Not typical profile for most.
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146kts with a failed engine? Must be almost vertical in a PA28. My POH says 79kts
?
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I told you further above that it’s on page 67 of the manual.
No need to try Ctrl+F, just scroll down.
I’m certainly not using a game documention if there are RW manuals available.
But if you want to understand where the quote comes from (that’s what you yourself asked), you better read where people cite from.
You then can still discredit the source.
See in the real POH I posted
SECTION 3- EMERGENCY PROCEDURES
9-134
“If failure occurs prior to or during descent:
Manifold Pressure… Maintain 1000 ft/min descent at 146 KIAS
Mixture… Full rich”
Erm, read again, this section has nothing to do with an engine failure!
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You are correct. It’s engine instruments failure. My bad.
That said, the 1000 fpm profile is just one example. 500-700 fpm is more typical.
Obviously you want to get down sooner if your instruments start going wonky.
79 KIAS is correct for engine failure, like you said. The power off glide speed.
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So let’s summarize this: 500-700fpm descent at around 145KTIAS. However you get there 
The manual has a hint on short increase of thrust during descent to avoid spark plug fouling and cooling off on the engine. I didn’t do that yet, maybe worth trying…
I am guessing that winds and turbulence are a factor as to why people reduce power for descent, but don’t know. Clearly not all GA pilots do it, if you read the discussion I linked to above. But seems like most do not reach top of green arc.
Well yeah, you avoid overstressing if you have room to the yellow range.
For me it is basically the convenience of proper VNAV calculation using the GNS530 which uses your current speed for the TOD.
If you speed up during descent, you basically need to start earlier (or increase fpm), don’t you?
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10-15 knots you will gain at 500 fpm if you keep power around 75%, i.e. same as cruise.
If you go to 1000 fpm you will gain more.
I am not quite sure what you mean, - your TOD is earlier if you have less fpm? Yes.
Does the in game or PMS-530 mod (or real unit) factor that your KTAS will be lower as you lose altitude?
Seems relevant
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No, I was saying if you calculate with the current speed (I’d assume ground speed is taken by the GNS) and then accelerating during descent, you’ll end up overshooting the descent profile.
You’d basically need to factor in the change in speed (ground speed actually) when calculating the profile and thus start the descent earlier.
At least the in-game one I think uses your GS to calculate the TOD (or rather time to descent). I think that’s also correct assuming the GS remains constant.
Thanks, I basically know how the VNAV page works. But since there is no way to input a descent speed, it simply has to use your current GS to calculate. Ending up wrong if you increase during descent.
You’ll then see that the VSR increases further, needing a deeper dive to stay on profile (or slow down again).
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Well since the book “Stick and Rudder” is so often quoted here in the forum let me impart some of Wolfgang Langewiesche’s wisdom here. And while this wisdom is older than most people here, and comes from a time before VORs and GPS when pilots flew more by feel than by data, I believe it still is valid.
Let me quote this from page 153 and 154:
“Stick and Throttle: The so-called elevator is really the airplane’s speed control, the throttle is really its up and down control. This is hard to believe but is one of the keys to the art of flying”
“The airplane’s real up-and-down control is its throttle. The pilot here gets climb, level flight and descent simply by changing the throttle setting, The stick is in the same position throughout, and if the airplane’s stability is flawless, the airspeed will be the same in all three flight conditions.”
Langewiesche supports Coppersens’s approach: according to the author, a stable aircraft will always try to remain at the speed it’s flying no matter the attitude it was flying at. So pulling back on the throttle will retain your speed while the plane starts to decent. Pushing the throttle forward will make the plane gain altitude at the same speed. (Always considering you are flying a stable plane like the Arrow III)
On the other hand, without touching the throtte, if you pull up you will continually lose speed until the plane stalls. And if you push the stick forward and thus the elevators (or flippers as he calls them) down, the plane will nose down and continually gain speed.
So in order to get a stable descend this way you always have do three things:
- you push the yoke/stick forward (plane noses down, descends and AND picks up speed)
- you have to pull the throttle back to keep the speed stable
- you have to re-trim
If you use Coppersens’s (and Langewiesche’s) approach to flying you will have the easier life because ideally you only will have to pull back on the throttle until you reach the desired descent rate. No pushing the yoke and no re-trimming.
And in my eyes this has nothing to do with “actively flying” the plane. It has something to do with knowing your plane, how it reacts to your input, and how to get it to do what you want it to with the least effort on both pilot and aircraft.
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Ah, okay. Yeah, well in the discussion I posted from https://www.pilotsofamerica.com/ there were some examples using GS in calculation.
But I would assume the 530 adjusts your VSR in real time like you said. So one can maybe do a calculation to add 10-15 knots difference so profile matches VSR. Or just reduce power first.
It does, but if you wait for the fpm to reach the value that you want to descent with, you may not speed up when starting descent to keep your VS and VSR in sync.
If you do the calculation manually, you have at least the option to add the ground speed increase for descent, but the GNS doesn’t allow that.
Thanks for the quotes. Sounds like a book worth reading.
I actually remember this kind of throttle control from some flying lessons on the C152 which reacts very well on throttle input and you get an almost instant feedback on the VS.
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That seems like a pain in the ■■■ vs just doing everything manually.
It works a treat if you keep the speed 
But needing to adjust the provided data for speed increase (like descending earlier or setting up more distance for the profile target) basically makes it not much better than direct manual calculation.
Maybe that evens out since if you descend with constant IAS, you first gain GS when initiating descent (compared to cruise) and while descending you end up losing GS. Maybe I should give it a try.
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That’s a good point!
Other thing is wind will change at different altitudes, so better to start descent a little earlier than needed, or alternatively 500 fpm can easily become 700 without much discomfort, then with reduced power to maintain speed. Whereas 1000 to 1200 is not so comfortable.
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