Emergency Descent

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Jim Hardin
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Emergency Descent

Post by Jim Hardin »

Curious as to what others teach in this area?
Most LSA POH are not much help.

My thinking is that there are 3 basic scenarios involved...

Airframe intact but get on ground fast.

Weather related, get below clouds.

Airframe probably compromised get down without down without losing more.

Others? Thoughts?
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drseti
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Re: Emergency Descent

Post by drseti »

Jim Hardin wrote:Airframe intact but get on ground fast.
If you mean get on the ground really fast (like a fire), I teach:

Engine and switches off - fuel valve off
Full flaps
Establish best glide speed
Roll into steep spiral (45 to 60 degree bank)
Stick back to maintain best glide speed
Weather related, get below clouds.
Assuming that you flew from acceptable into deteriorating weather:

Establish level, stabilized slow flight at best glide speed
Initiate shallow-banked 180 degree turn
If ceiling is dropping, power back to idle, full flaps, descend while maintaining best glide speed
When 500 below clouds, add power to level off in slow flight
Fly back to airport and land
Airframe probably compromised get down without down without losing more.
Power back to idle
Descend at top of white arc
Don't extend flaps
Fly aircraft on well above stall speed
Others? Thoughts?
Engine failure on takeoff:

Maintain best glide speed
Land straight ahead +- 30 deg, unless >1000 ft AGL
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
Prof H Paul Shuch
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3Dreaming
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Re: Emergency Descent

Post by 3Dreaming »

drseti wrote:
Jim Hardin wrote:Airframe intact but get on ground fast.
If you mean get on the ground really fast (like a fire), I teach:

Engine and switches off - fuel valve off
Full flaps
Establish best glide speed
Roll into steep spiral (45 to 60 degree bank)
Stick back to maintain best glide speed
Paul, I bet in some airplanes under the right circumstances you might be going up instead of down set up like that. Think Taylorcraft in a big thermal.

If I'm on fire I am going do like Paul said, fuel and switches off, but unless I am right over where I need to land I am going to push the nose down and accelerate to close to VNE, with possibly a little slip. If I am over where I want to land, then maneuvering speed 60° bank steep spiral.

For flight into weather assuming you already had the airplane trimmed. Hands off the wheel. or at minimum light pressure to keep airplane stable. Feet on the rudder pedals. Reduce power to give 500 foot rate of descent, you should know what that number is for your airplane. Keep your heading, or if you need to make a turn use rudder only and make no more than standard rate turn. Roll out of turn with rudder. I have not found an airplane yet that this didn't work. Of course if you have a working autopilot use that to get you out of trouble.
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Jim Hardin
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Re: Emergency Descent

Post by Jim Hardin »

Interesting.

ACS/PTS only mentions 45 degree banks. I would stick with that, as going to the 60 deg. Is flying an emergency in a seldom practiced maneuver (my opinion).

Rudder only :shock: I favor ALL turns/ corrections to be made with coordinated inputs. Again, my opinion.

Still all are interesting comments that I will consider.
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Re: Emergency Descent

Post by drseti »

Jim Hardin wrote:ACS/PTS only mentions 45 degree banks.
True. But if I'm on fire, I want to get down as quickly as possible. That means diverting as much lift as possible from the vertical to the horizontal. Of course, I wouldn't suggest anyone should bank 60 degrees without proper training!
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
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joey4420
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Re: Emergency Descent

Post by joey4420 »

To get to the ground fast, I cut power pull back on the yoke and wiggle the wings... 1500-2000 feet per minute decent... your ears will pop.

Or maybe this is only good for an Ercoupe.
Joey
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Re: Emergency Descent

Post by 3Dreaming »

Jim Hardin wrote:Interesting. Rudder only :shock: I favor ALL turns/ corrections to be made with coordinated inputs. Again, my opinion.
With small rudder inputs I can keep the ball as close to center as most students do trying to make a coordinated turn. I had an old lady former military link trainer instructor, flight school owner, DPE teach me how to do precision approaches using this method. It helps prevent overcontrolling. Lots of non instrument rated flight into IMC accidents happen due to loss of control caused by overcontrolling. It is a simple way to help pilots keep from losing control in an emergency.

Things are different if you are instrument rated with lots of instrument time.
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Re: Emergency Descent

Post by drseti »

I agree with that technique, Tom - except I can never seem to make it work in the Ercoupe! :twisted:
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FastEddieB
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Re: Emergency Descent

Post by FastEddieB »

Jim Hardin wrote: ACS/PTS only mentions 45 degree banks. I would stick with that, as going to the 60 deg. Is flying an emergency in a seldom practiced maneuver (my opinion).
At least for the Commercial ACS, pilots need to demonstrate a steep spiral:

“Apply wind-drift correction to track a constant radius circle around selected reference point with bank not to exceed 60° at steepest point in turn.”
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Re: Emergency Descent

Post by 3Dreaming »

drseti wrote:I agree with that technique, Tom - except I can never seem to make it work in the Ercoupe! :twisted:
Your just not flying the right Ercoupe.
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Re: Emergency Descent

Post by drseti »

3Dreaming wrote: Your just not flying the right Ercoupe.
I'm sorry, Tom, I'm a purist. If you're suggesting one with rudder pedals, I contend that's not a real Ercoupe.
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
Prof H Paul Shuch
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MrMorden
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Re: Emergency Descent

Post by MrMorden »

drseti wrote:
Jim Hardin wrote:Airframe intact but get on ground fast.
If you mean get on the ground really fast (like a fire), I teach:

Engine and switches off - fuel valve off
Full flaps
Establish best glide speed
Roll into steep spiral (45 to 60 degree bank)
Stick back to maintain best glide speed
Hmm...seems to me you could get a better descent rate by leaving flaps up and pitching over to Vne or fastest dive, whichever is lower. The max speed on full flaps on many airplanes is quite low, on my CT it's only 62kt. That is going to hinder how fast you can get down, as I'd overspeed at something like 600-750fpm descent. At close to Vne with no flaps and power off I can come down at probably 1500-2000fpm.

In this scenario I don't want best glide or anything close to it, I want best descent rate.

Am I wrong about this?
Andy Walker
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drseti
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Re: Emergency Descent

Post by drseti »

I guess it depends on the plane, Andy. In mine, the 50 degree flaps give you so much drag that you drop really fast. The 60 degree bank diverts what lift there is mostly to the horizontal. And at slow flight, the wing has lost some of its inboard lift (though you still have really good aileron control). I'd say everyone should run the experiment (at altitude, of course) to see what works best for them.
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
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Wm.Ince
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Re: Emergency Descent

Post by Wm.Ince »

MrMorden wrote:...seems to me you could get a better descent rate by leaving flaps up and pitching over to Vne or fastest dive, whichever is lower. The max speed on full flaps on many airplanes is quite low, on my CT it's only 62kt. That is going to hinder how fast you can get down, as I'd overspeed at something like 600-750fpm descent. At close to Vne with no flaps and power off I can come down at probably 1500-2000fpm.
In this scenario I don't want best glide or anything close to it, I want best descent rate.

Am I wrong about this?
No Andy . . . you are quite right.

I would only add (LSA) . . power should be at idle, and during the Vne descent, enter a medium bank, which will increase the rate of descent even more. A steep bank at Vne is optimal for max rate of descent.
Of course, down at the bottom, a deceleration will be necessary. That's where drag should be added, such as slipping and extending flaps on schedule.
Bill Ince
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MrMorden
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Re: Emergency Descent

Post by MrMorden »

drseti wrote:I guess it depends on the plane, Andy. In mine, the 50 degree flaps give you so much drag that you drop really fast. The 60 degree bank diverts what lift there is mostly to the horizontal. And at slow flight, the wing has lost some of its inboard lift (though you still have really good aileron control). I'd say everyone should run the experiment (at altitude, of course) to see what works best for them.
I an see using the turn to add drag and increase the descent rate...but now you are at relatively low speed in a 2g bank, and risking an accelerated stall. In my high speed way of thinking, I am coming down like a meteor and I can put in as much bank as I want up to the airframe limit (though admittedly my turn radius is *much* larger) while looking outside at the planned landing zone, instead of watching the ASI and sweating the stall.

As Bill said, in the high speed method there is definitely an energy management problem at the bottom. Though on the plus side you arrive close to the ground with a lot of energy to maneuver or glide.

I'm not saying your method is wrong, I'm just saying how I'd prefer to do things...
Andy Walker
Athens, GA
Sport Pilot ASEL, LSRI
2007 Flight Design CTSW E-LSA
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