Constant Aspect Approach - anyone know how to do this?

alfadog

alfadog

Final Approach
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alfadog
So I came across this supposedly magical engine-out approach:

http://www.gremline.com/index_files/page0035.htm

My take-away from that article is that you set up this approach, fly it, then magically level out at 300' and on final at the correct height to make the threshold, all power-off.

So yesterday I tried it in the 172. From midfield downwind, I picked my aim point, pulled the power, set best glide, judged my depression angle as best I could then tried to spiral down at a constant visual depression angle. At 200' I was off the wrong side of the runway and fixing to cross it midfield. Needless to say, I applied power and climbed out.

Yet a seach shows this as a technique for mainly gliders and hang-gliders. Is this applicable to a Cessna? How do you hold a constant sight angle? Especially when the wing blocks the horizon above your aim point in turns?

edit: A fellow at PPrune (where I originally saw this referenced) has given me another link that clarifies that the magic only happens if you set this up correctly. That makes a lot more sense to me than the impression I got from the first link that you can start this from anywhere and come out on final.

http://www.lynehamaviation.co.uk/documents/ex17-PFL.pdf
 
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The glider trainining I've had emphasises the "TLAR" (that looks about right) approach. Throughout the pattern, keep looking and asking yourself if it looks right - am I high or low? Then adjust and repeat.

I think the constant sight angle was covere in Stick and Rudder? I'll have to dig that out and see what he says.
 
That article is an overly complicated way of saying that for each aircraft type, learn what angle below the horizon you can glide to power off, and turn toward your intended touchdown point once you've intercepted that angle relative to it. I do this subconsciously on each landing I make, after pulling power abeam the numbers. Doesn't matter whether you do it from 1500'AGL or 500' AGL, the sight picture is the same.
 
Not 100% on topic but I read somewhere about a procedure for flying a power off ILS approach in the event of a single engine failure. Anyone have a link to that or tried it?
 
dell30rb said:
Not 100% on topic but I read somewhere about a procedure for flying a power off ILS approach in the event of a single engine failure. Anyone have a link to that or tried it?
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ILS is at most 3.5 degrees = 16:1 glide ratio. Not in a Cessna.

edit: also full-scale deflection is 1.4 degrees top to bottom so you are not going to get usable information that way either, i.e. flying some off-center glideslope. You are descending at about 6 degrees. You could certainly use the localizer and figure your descent rate and hope to make the field (good luck) but then it is not an ILS.
 
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dell30rb said:
The procedure did not involve tracking the GS
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Oh, then it is not an ILS approach, it is a localizer approach. Yes, that would certainly be worth a shot if your only option. Better would be a spiraling descent over the airport, IMO.
 
dell30rb said:
Not 100% on topic but I read somewhere about a procedure for flying a power off ILS approach in the event of a single engine failure. Anyone have a link to that or tried it?
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Assuming best glide is around 9:1 for a Skyhawk, less for many others... that's slightly greater than a 6 degree glideslope. ILS is typically 3.

Your only hope is to trade speed for altitude at the engine failure and then best glide speed.

You have zero chance of holding the glideslope. Only the localizer. Especially with a headwind. Which you'll probably have.

You'll fall through the glideslope again somewhere up ahead and hope you make the runway or go visual and see something soft(er) to land on/in.

You get that extra 1000' of runway prior to the touchdown zone to maybe make it, since the glideslope leads to that, not the runway threshold.
 
You'll fall through the glideslope again somewhere up ahead and hope you make the runway or go visual and see something soft(er) to land on/in.
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-don't try to nail the loc; need to be a degree off in order to land beside the approach lights and not on them. Assuming they are in a field and not surrounded by buildings or forest etc.
 
dell30rb said:
http://www.pilotsofamerica.com/forum/showpost.php?p=797201&postcount=34

"The MOPA has developed an ILS porcedure for power off ILS it's gotten so bad. There is no other type fleet that has this."

Curious how this works
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Here is one way it could work:

Set minimum speeds for the various portions of the ILS that would allow you to trade speed for altitude and make it to the runway using the localizer, ex, beyond the OM maintain 160 kt, from OM to MM, 140. Something like that.
 
On a garmin 430 there is a feature where you can plug in your waypoint and it shows required FPM decent etc. I know there is a better term for this feature.

If you are sharp with the 430 you might be able to utilize it especially if things go bad at a higher altitude.
 
Most glideslopes are 3 degrees which requires a 19 to 1 glide ratio or about twice the typical GA airplane is capable of.
 
Even the old KLN 90B's had this feature.

Mike5250 said:
On a garmin 430 there is a feature where you can plug in your waypoint and it shows required FPM decent etc. I know there is a better term for this feature.

If you are sharp with the 430 you might be able to utilize it especially if things go bad at a higher altitude.
Click to expand...
 
Mike5250 said:
On a garmin 430 there is a feature where you can plug in your waypoint and it shows required FPM decent etc. I know there is a better term for this feature.

If you are sharp with the 430 you might be able to utilize it especially if things go bad at a higher altitude.
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You may be talking about advisory glidepath

wabower said:
Even the old KLN 90B's had this feature.
Click to expand...
My KLN-94 does not, though I'm not sure if it's an installation issue or software.
 
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