E_Dawg
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What about normal every day descents on a cross country?
Losing Its Luster
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What about normal every day descents on a cross country?
Screaming_Emu
Well-Known Member
We used the charts in the POH to figure out top of descent for fuel burn, time, and distance....which I know only helps if everything goes according to plan.
Otherwise I just did some mental math, 500ft/min, 5,000ft to lose, etc....
dasleben
That's just, like, your opinion, man
Screaming_Emu
Well-Known Member
And if they don't go to plan?
...3:1 rule.
"that's because I was inverted"
ppragman
No pasa nada.
Lol, seriously? That's never worked or been practical in any way shape or form for me ever. And I've tried! There's too many variables, too many changes in wind velocity, updrafts and turbulence, and multiple other factors which skew your calculated results. The only way to go is 3:1 6:1 if you're in an unpressurized, VNAV on the screeen, or a little mental math if you've got a GPS.
Screaming_Emu
Well-Known Member
Worked out pretty well for me. And in a training piston plane on a training flight, if it was a little off, it wasn't a huge deal as its pretty easy to lose altitude and slow down quickly. Which was kinda my point.
dasleben
That's just, like, your opinion, man
I agree that it works well with light training aircraft, particularly with a student who's used to higher descent rates. Flying anything bigger than that requires a bit of planning, though. Especially true if you're carrying the general public. Way easy to get high/fast in a 400-series Cessna piston, for instance.
The problem comes down to that "inbreeding"...the instructors don't have the experience to know to teach it to their students. The cycle continues.
ppragman
No pasa nada.
That's surprising to me, based on weather, traffic, and a multitude of other things (including whether ATC would let me lower, or terrain would permit it) my performance calculations based on flightplanned book values has been up to 20% off at times. For example, let's say you're flying a small piston single, chances are the book values say that it will fly a lot faster than it actually will, that it climb a lot faster than it actually will, and burn less fuel than it actually will. I figure at least 15% poorer performance than predicted. That poorer performance initially jacks with fuel required, as in you'll need more fuel than predicted to complete any flight, then it jacks your cruise speeds, then it jacks your top of descent location. Personally, I just play it by ear all the time and adjust as required to maintain my desired performance at the time.
For performance data, if I'm really on the edge of the envelope, I use data that I've gathered to get my own idea of what's going on. I have a book that I occasionally write notes about airspeeds, takeoff performance, climb performance and a multitude of other notes. If I'm going somewhere where performance into and out of is really going to be an issue (and for what I'm flying, that'd be less than 2000' ALD, then I'll consult my notes or my memory.
wheelsup
Well-Known Member
you're the chuck norris of aviation
this discussion is getting a little too hard core for me
Polar742
All the responsibility none of the authority
So is this based on experience, or did you fly this way when you were learning too?
Screaming_Emu
Well-Known Member
Again, training flight in the middle of freakin nowhere, usually in really good weather is very different than flying professionally in bad weather out of a busy airport.
And my company would shart themselves if I used a "book of notes" to come up with my own performance numbers.
dasleben
That's just, like, your opinion, man
Eh, 135 flying isn't always cut and dry like (domestic) 121 is.
ppragman
No pasa nada.
You're telling me you don't take note of that stuff? Performance data in light singles can vary very far from the published data.
ppragman
No pasa nada.
Lol, usually its, "well, the book says I can put it down in 950', however, with the wind and conditions we've got today, combined with the fact that this is an old ass airplane, the best I've been able to do in similar conditions is around 1400." So, plan for 1400'. What's the problem with that?
Screaming_Emu
Well-Known Member
Nothin at all, I just figured you were talking about fudging the numbers in the other direction. My bad.
ppragman
No pasa nada.
There are times when you perform better than anticipated, and you keep track of those, but its usually from a fluke gust of wind, or something. Then you can say things like, "ehh, if the wind is blowing the right direction you'll get off sooner, but get a downdraft on climbout. So initial climb performance is reduced and you may have to do s-turns up the valley."
You'll eventual learn that performance data varies in ALL airplanes. I don't have the time, patience, or reason to take notes. I make sure the plane can do it by the book which has fudge factors built in. I go. I land. I drink beer.
If you get some satisfaction out of knowing your takeoff roll everyday vs. the next all the power to you.
That has nothing to do with the gains of having a SOLID aviation education. If Embry - Riddle was free everyone would think it's the end all be all. Because it's overpriced it's popular to knock it.
Screaming_Emu
Well-Known Member
gigantic :yeahthat:
I can't :yeahthat:the 2nd part because I went to UND and paid half for my education
ppragman
No pasa nada.
I do get satisfaction in knowing how my ship will perform, its also useful information to know if I have to put down on a road or on the beach, "will I make it given my previous performance?". And considering I do between 10 and 20 takeoffs and landings on an average summer day I get lot's of data.
Also, there's not that much of a fudgefactor if you don't have accelerate stop and accelerate go data for your airplane.
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