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Stuck above the clouds with no instruments

Posted: Mon Jan 13, 2020 7:50 am
by pelmet
Why the heck did you get yourself into that position in the first place as it wasn't legal to fly over that ceiling anyways. Or maybe it was as you are in the US in an N registered plane and though that it would be clear at destination.

Turns out that it is 2500 overcast ceiling with good vis underneath. Fuel is getting low, less than 30 minutes available. Now how are you going to get down safely from above 10000 feet to the clear air below in your typical general aviation trainer aircraft? Altimeter and airspeed are working.

Re: Stuck above the clouds with no instruments

Posted: Mon Jan 13, 2020 9:20 am
by porcsord
Spin.

Re: Stuck above the clouds with no instruments

Posted: Mon Jan 13, 2020 9:42 am
by pelmet
Well...here is an example of a long spin. One would just have to be patient, make sure to hold the appropriate controls at full deflection, and wait. The video gives a good example of rate of decreasing altitude on the altimeter during the procedure.....

http://www.aceaerobaticschool.com/spins/

Re: Stuck above the clouds with no instruments

Posted: Mon Jan 13, 2020 9:48 am
by digits_
Remember your training and fly through the cloud layer?

Trim the plane for hands off flight with a fixed power setting and a vertical speed of 800 fpm and let go.

If you have 390 minutes left, you can probably get back from where you came.

I would advise against spinning it through. I think one would be too disoriented to recognize when one is out of clouds and in which direction to apply the recovery. If you can properly handle that, you shouldn't have a problem just flying through it either.

Re: Stuck above the clouds with no instruments

Posted: Mon Jan 13, 2020 9:58 am
by rookiepilot
pelmet wrote: Mon Jan 13, 2020 9:42 am Well...here is an example of a long spin. One would just have to be patient, make sure to hold the appropriate controls at full deflection, and wait. The video gives a good example of rate of decreasing altitude on the altimeter during the procedure.....

http://www.aceaerobaticschool.com/spins/
Uhhhhh.... no thank you as a recommended strategy. This is what one would recommend to a low time PPL???? :roll:

Digit's post is the way to go.

Re: Stuck above the clouds with no instruments

Posted: Mon Jan 13, 2020 1:03 pm
by pelmet
rookiepilot wrote: Mon Jan 13, 2020 9:58 am
pelmet wrote: Mon Jan 13, 2020 9:42 am Well...here is an example of a long spin. One would just have to be patient, make sure to hold the appropriate controls at full deflection, and wait. The video gives a good example of rate of decreasing altitude on the altimeter during the procedure.....

http://www.aceaerobaticschool.com/spins/
Uhhhhh.... no thank you as a recommended strategy. This is what one would recommend to a low time PPL???? :roll:

Digit's post is the way to go.
digits_ wrote: Mon Jan 13, 2020 9:48 am Remember your training and fly through the cloud layer?

Trim the plane for hands off flight with a fixed power setting and a vertical speed of 800 fpm and let go.

If you have 390 minutes left, you can probably get back from where you came.

I would advise against spinning it through. I think one would be too disoriented to recognize when one is out of clouds and in which direction to apply the recovery. If you can properly handle that, you shouldn't have a problem just flying through it either.

Thanks,

Remember the title of the thread....No instruments. Except of course, the FAA/TC required stuff such as airspeed and altitude. In other words, you are in some sort of old taildragger type or in an aircraft with certain unserviceable instruments. So, if you go into the cloud, you are pretty much guaranteed to lose control.

High speed spiral dive is inevitable followed by possible structural failure. With the spin(assuming it is an aircraft certified for spins with no restrictions), you are in a steady and safe state. You will know precisely which way to recover when you break out because you have full pro-spin rudder input and can simply input opposite rudder to whatever you had during the spin. Or, you can use a well known recovery technique...….remove hands and feet from the controls and let the aircraft self-recover.

So, low time or high time pilot.....trimming and descending into cloud is likely fatal. Do the spin thing if there is room for recovery.

Re: Stuck above the clouds with no instruments

Posted: Mon Jan 13, 2020 1:28 pm
by digits_
I do not think a typical trainer would go into a spiral dive if you let go of the controls. I'm actually pretty sure it won't. Sure you'll make some turns and will go a bit up and down, but nothing too crazy. If you can resist the urge to "help it out" or "correct it a bit".

You're right that without instruments "flying out of it" might be extremely hard to do. The second option stays valid though.

Re: Stuck above the clouds with no instruments

Posted: Mon Jan 13, 2020 1:36 pm
by ant_321
The spin method was brought up at the hangar a few times when I was learning to fly gliders. It could work. That being said, when I was a flight instructor I saw plenty of students put themselves into a spiral dive when trying to spin a 172.

Re: Stuck above the clouds with no instruments

Posted: Mon Jan 13, 2020 2:40 pm
by photofly
digits_ wrote: Mon Jan 13, 2020 1:28 pm I do not think a typical trainer would go into a spiral dive if you let go of the controls. I'm actually pretty sure it won't. Sure you'll make some turns and will go a bit up and down, but nothing too crazy. If you can resist the urge to "help it out" or "correct it a bit".

You're right that without instruments "flying out of it" might be extremely hard to do. The second option stays valid though.
In level flight they do actually enter a spiral dive, if you wait long enough. If the lateral trim isn't very good (one wing tank heavier, or asymmetric passenger loading) it doesn't take very long. If you want, I will post my "let go of the controls" GPS and AHRS plots from my experiments in the 182, again.

A fatal spiral dive is what happened in this accident when everyone in the plane fell asleep:
http://publications.gc.ca/collections/c ... 17-eng.pdf

however in a descent, lateral stability is improved, so you may get away with it.

The spin is not a totally silly idea, except even spin-approved types are required to demonstrate recovery up to only six turns; and as someone mentioned, if it's a 172 it can be tricky to keep it in a spin without adding power through the manoeuvre, and do you want to be working out how much power, in IMC during your emergency descent?

Re: Stuck above the clouds with no instruments

Posted: Mon Jan 13, 2020 2:48 pm
by digits_
photofly wrote: Mon Jan 13, 2020 2:40 pm
digits_ wrote: Mon Jan 13, 2020 1:28 pm I do not think a typical trainer would go into a spiral dive if you let go of the controls. I'm actually pretty sure it won't. Sure you'll make some turns and will go a bit up and down, but nothing too crazy. If you can resist the urge to "help it out" or "correct it a bit".

You're right that without instruments "flying out of it" might be extremely hard to do. The second option stays valid though.
In level flight they do actually enter a spiral dive, if you wait long enough. If the lateral trim isn't very good (one wing tank heavier, or asymmetric passenger loading) it doesn't take very long. If you want, I will post my "let go of the controls" GPS and AHRS plots from my experiments in the 182, again.

A fatal spiral dive is what happened in this accident when everyone in the plane fell asleep:
http://publications.gc.ca/collections/c ... 17-eng.pdf

however in a descent, lateral stability is improved, so you may get away with it.
Oh right, I vaguely remember that.

The report says:
The aeroplane struck the ground on an easterly heading, approximately 45° right bank, pitch angle 7° to 8° nose down, airspeed 140 knots.
If that is as bad as it gets, then I would still recommend this approach. Recovering from this attitude, when you know it is going to happen at some point, should be well within the skill level of any pilot with 2500 ft remaining - if they are awake.

Re: Stuck above the clouds with no instruments

Posted: Mon Jan 13, 2020 4:21 pm
by goingnowherefast
Spin used to be the technique of choice way back before they invented the fancy gyroscopic instruments. I'm talking 20s and 30s. If I'm in a plane that will be stable in a spin, at 10000' and it's 3000' agl overcast, I can't divert to somewhere nicer, I'd probably give it a go.

This is also a situation where a superior pilot uses their superior judgement to avoid having to use their superior skill. I'd have to ask how the flying F#%K somebody got in this situation in the first place. Clouds are pretty easy to see, once they're becoming anymore than a few layer, time to go under the layer and/or go somewhere else. Can't say I've ever watched clouds go from 0 to thick overcast in the time it takes to fart.

Re: Stuck above the clouds with no instruments

Posted: Mon Jan 13, 2020 5:07 pm
by lownslow
The Cessna 150 manual has a procedure for this.

Re: Stuck above the clouds with no instruments

Posted: Mon Jan 13, 2020 6:31 pm
by whistlerboy02
Full Flap
Throttle set “mid range” adjust for desired decent rate
Use rudder only to maintain approx heading
DO NOT TOUCH THE YOKE
Sit on your hands, ignore the stall warning ect and as long as you only use the rudder it should bring you safely down through the layer

Re: Stuck above the clouds with no instruments

Posted: Mon Jan 13, 2020 11:38 pm
by photofly
digits_ wrote: Mon Jan 13, 2020 2:48 pm
Oh right, I vaguely remember that.

The report says:



If that is as bad as it gets, then I would still recommend this approach. Recovering from this attitude, when you know it is going to happen at some point, should be well within the skill level of any pilot with 2500 ft remaining - if they are awake.
That was as bad as it got in the time from 4500asl until they struck the ground at about 1000asl. It clearly hadn’t reached a stable limit, and it might never reach a stable limit at all, or at least until the wings fell off at 4.4g plus the safety factor. In this hypothetical situation you have three times as far to descend. How lucky do you feel?
whistlerboy02 wrote:as long as you only use the rudder
Fine. But with no instruments, how do you know how much and which rudder to use, genius?

Re: Stuck above the clouds with no instruments

Posted: Tue Jan 14, 2020 6:44 am
by lownslow
photofly wrote: Mon Jan 13, 2020 11:38 pm Fine. But with no instruments, how do you know how much and which rudder to use, genius?
Image

Re: Stuck above the clouds with no instruments

Posted: Tue Jan 14, 2020 1:20 pm
by trey kule
Its the cold,right?
Nobody has anything better to do.

How many angels can dance on the end of a pin?

As I read this, the problem is we have an incredibly stupid pilot who allowed themselves to get on top of an undercast with virtually no instruments.. not even a ball and needle apparently, as someone asked about how much rudder?

Should we be contemplating the question itself, to seek knowledge, or questioning the whole idea of asking this question.

Other than the AN 2 which specifically addresses this situation, I have no idea of the correct answer. As someone else mentioned, better to learn how to avoid getting yourself in this situation in the first place. The technique then becomes irrelevant.

Back in the 1960s when I learned to glide, we were taught to thermal into the cloud then spin out...but it was a lot more than 2500 AGL, and most gliders are rather nice spinners, but can get over Vne in a heartbeat in a spiral.

From a cycle of control,standpoint then, a spin would be better, as we are controlling the yaw
I am not convinced many pilots could hold a 172 in a spin for several thousand feet though. At least not one of the swept tail ones.

And I too, have now wasted precious life time on a silly scenario.

Re: Stuck above the clouds with no instruments

Posted: Tue Jan 14, 2020 3:02 pm
by photofly
It's actually the Kobayashi Maru all over again. The correct answer is to alter the plane so it has instruments.
Or I guess you could just change the weather.

Re: Stuck above the clouds with no instruments

Posted: Tue Jan 14, 2020 4:35 pm
by Heliian
photofly wrote: Tue Jan 14, 2020 3:02 pm It's actually the Kobayashi Maru all over again. The correct answer is to alter the plane so it has instruments.
Or I guess you could just change the weather.
Nice trek reference.

What would I do in my helicopter though?

Re: Stuck above the clouds with no instruments

Posted: Tue Jan 14, 2020 4:47 pm
by digits_
Heliian wrote: Tue Jan 14, 2020 4:35 pm
photofly wrote: Tue Jan 14, 2020 3:02 pm It's actually the Kobayashi Maru all over again. The correct answer is to alter the plane so it has instruments.
Or I guess you could just change the weather.
Nice trek reference.

What would I do in my helicopter though?
Switch of your engine and restart once you've fallen through the clouds :mrgreen: :?:

Re: Stuck above the clouds with no instruments

Posted: Tue Jan 14, 2020 7:52 pm
by whistlerboy02
Photofly I always liked you, till today.
Use the whiskey compass for a heading