Just a PC IMC theoretical question

[carl]

This is a purely theoretical question. 

I have recently been flying with the Positive Control (PC) operating . In its simpler form this levels the wings and nothing more.

I was thinking of a situation where a VFR pilots end up in IMC conditions and loses control and crashes. Lets say a descent from VFR on top,through a cloud deck to VFR below.

Would the PC prevent this. Or would the feeling of turning be so great the pilot would override the PC and then lose control. A case of not trusting his instruments ( he is just a VFR pilot).

I was thinking about this today driving home from work with a nice cloud deck overhead. 

Carl

[Danb]

I am not familiar but if one were a vfr pilot and slipped into Ifr ,mvfr started to get spatial disorientation, vertigo etc, I'd assume the PC system would become your best friend, think John Kennedy accident going into the island in Mass.  Maybe if he just hit his autopilot he would still be here.

at one time as a new pilot flying on a clear moon,star filled sky ..I became disorientated. Could not determine the sky from the lights on the ground, I remember being quite scared and nervous I clearly did not want my passenger to know I remembered to use the autopilot and flew it almost all the way to the runway...I had maybe 90 hours, truly kissed the ground and started flying with my instructor at night plus then began my IFR training sooner than planned.

so a long winded yes ..in my camp

 

fly safe use all the tools at your disposal..they may save you..

[carusoam]

A wing leveler is a helpful tool.  It will help you fly directly ahead...

constant power will maintain altitude.  Removing an inch of MP, will start a descent of about 100fpm more inches, higher descent rate....

Trim is your friend.  constant trim will maintain air speed.

All this constancy allows the PP to gain time to think.  Select the heading that is 180° behind, turn slowly for that direction...

Where the novice pilot may run into a challenge is performing the U-turn.  A standard rate turn is good to know.  Generally speaking set a 15° angle of bank.  Know how to use the TC to set a constant standard rate turn.

see what adding the heading bug to the system does.  Depending on how the system is set up...the heading selector can turn the plane at a constant rate towards the new heading.

practice with a CFI using these tools.  Don't rely on my description.

The modern version of the same thing is a KAP150.  It holds the wings level.  In heading mode, it turns at standard rates to the heading bug. In addition it has altitude hold and a few other things...

unfortunately, in bumpy weather, the computer and gyros may not keep up with what is going on.  You are left flying the plane no matter what.

I am a PP, not a CFI...

best regards,

-a-

Edited September 23, 2015 by carusoam

[Bob_Belville]

The original PC system (provided by Brittain) was a big help in my first '66 E. (I did add a STEC) It would indeed keep wings level. It had a small trim knob which could be tweaked to pretty effectively hold a heading. I think it was primarily intended to hold the wings level while the pilot looked away from the panel, to tune a radio, read a chart, etc. But I think it could save a VFR pilot under poor visibility conditions. I often notice that passengers often react dramatically to entering IMC. They sense that the plane is turning even though the pilot, trusting his instruments, is scanning AI, DG, ASI, etc. and is paying no attention to what his body might be sensing. 

[irishpilot]

Any autopilot/wing leveler can be overridden by a spatially disoriented pilot. I think the big difference is training.  If said individual is IFR trained or at least has experience in recognizing unusual attitudes, they are more likely to use the tools available to fight against Spatial D.  If you fly long enough, you will become disoriented at one point (can happen VMC or IMC). The training is what saves pilots.

[StinkBug]

Not only will the PC help keep the plane right side up, but I've found that in turbulence it actually reacts and counters the bumps better than I can and creates a smoother ride. My A/P is just the brittain add on that ties into the PC and it works wonderfully, even without all the bells and whistles that more modern autopilots have. The key is to use it, and trust it, even when you feel like you shouldn't.

[carusoam]

There will be a limit to the bumps that it will handle.  The ones that you intentionally fly through are expected to be OK...

The ones that are generated by vertical gusts caused by thunder storms may be different.

Of course, the theoretical question did specify a pilot descending through a cloud layer...

Which is about the equivalent of private pilot skills from initial training.  The kind you get from flying under the hood.

Clouds are noticeably different but not tremendously different than the air.

I am staying with the training you have is better than the wing leveler you have.  Because you still need to turn around and the wing leveler doesn't do that on its own...

buy an hour of a CFII's time to review and practice the U-turn under the hood.  If all goes well, buy a few more hours until the IR is fully earned.  

The  whole idea of doing it in your plane is that it gives you the confidence that you and your systems are up to the task.  Turns to a heading and maintaining altitude would be very helpful. Talking to ATC and descending through a layer can be done in an emergency.  Knowing your plane and pilot is capable of this is important as well...

Flying a Mooney XCountry often without an IR will probably get you stranded above a cloud deck looking for a hole or doing a U-Turn in some deteriorating weather.  It is better to get the training started earlier than later...

this comes from my experience.  Wouldn't want to repeat it if I didn't have to.  The east coast has many days that will leave a pilot wanting to scud run under clouds or stuck above the clouds looking for a hole or flying into a cloud bank near the ocean.

You will want to have the skills that the wing leveler can only back-up. It's not that hard or too expensive...

best regards,

-a-

 

Edited September 23, 2015 by carusoam

[carusoam]

The really cool thing about the IR...

There is only one level.  It allows you to take off, fly, and land in IMC...

There isn't a sport version that limits you to certain things like descending through clouds only....

The limitations you set are mostly personalized to the pilot and his equipment.

The part I like the most, is what this thread is about.  Ascent and descent through cloud layers.

Avoid ice and thunderstorms....

How far off base is my response this time?

I ran out of space above..,

-a-

[Hank]

The PC will generally keep you straight. The heading bug will turn at more than standardrrates. In spatial D, will you let go of the yoke and trust the PC to keep you straight? 

I hit mtn obscuration once, which didn't bother me until cloudy stuff flashed by my window. Then I locked onto the AI and used the TC to make a standard rate 180; asked my wife to tell me when it was clear out front. Started IR training the next week. 

PC can keep you level, if you let it. Don't recall how much I held the yoke then, but I keep a hand on it all the time, more so when it's bumpy and two hands if too bumpy. 

PC is great and will be your friend on XCs, but get some training too.

[carl]

thanks for all your input

yep IFR rating is coming . 

[Shadrach]

The best thing to do when disoriented is nothing too drastic. 

[bonal]

One of the first things my primary instructor taught me when learning the instruments was that my airplane knows how to fly a lot better than I do. If your trimmed right and your plane flys level it's not going to turn into the devil because you can't see. Hope to get the I rating some day but right now it's a time and money thing. My Stec 40 works great and the 2 times I got into a no vis condition (smoke not clouds) I let it do its job with a safe and mostly stress free out come.

[Marauder]

I think the challenging part of any autopilot is trusting that it will do what you need it to do. And then to resist the temptation to try to do it yourself better.

There are limits to what an autopilot can handle and it is good to know what they are.

Sent from my iPad using Tapatalk

[Mooneymite]

I'm instrument rated.  The PC is a great work reliever when flying in the clouds for a long time (or in the clear!).  The ability to relax your scan long enough to study an approach, or look up a frequency is, well, priceless.  Single pilot IMC without at least a wing leveler is very tiring.

The PC would be a terrific aid to a VFR pilot who got into a situation where he had to fly in IMC.  A Mooney will naturally pitch to trim speed, so if the PC keeps the wings level, the VFR pilot's work load is drastically reduced.

Having said all that, I hope no VFR pilot will push the weather because he believes his PC is an ace-in-the-hole.

[Yetti]

So there I was last night flying along no hands on the yoke steering with my feet hazy day but not too bad.  PC leveler working great (gone through last year by Brittian) plane trimmed out thinking to myself this flying thing is pretty cool...   One landing was OK the other a bit better.  Overall the PC lessons the work load so you are not as tired out thus more alert and more able to deal with issues as they may pop up.

[Shadrach]

I think PC is one reason Mooneys have had such a great run in terms of inadvertent IMC accidents. There were over 4,000 M20s delivered with the PC system installed.  That is likely over half of the fleet.  Its dirt simple to just let go of everything in the event of disorientation. Even if you had an issue at high altitude, if you pulled the power back 4" before you went gooey, you'd likely arrive at a breathable altitude with a chance to regain control of the aircraft. 

[Hank]

My only bout with spatial D was on an IFR flight. I had filed for 10K, tops were supposed to be just below 9000, so I was looking forward to flying in the clear. Oops! Bottoms were about 9300 or so, and when I leveled off and accelerated, the hardest thing for me to do was nothing. The heading bug was set during climbout, but I would have sworn I was in a descending left spiral. "Trust your instruments" was combatting my inner ear, and I still managed to oscillate 200-300 feet or so, but letting go to trim was extremely difficult.

Thus we train and train and practice, practice, practice! The PC wouldn't have helped a whole lot by itself, as I was still trimmed for climb, creating altitude oscillations. I was sweating hard, but kept hearing my CFII, "trust your instruments" and concentrating on the AI. Who knows what would have happened had I "leveled" the yoke off to the right while trimmed for climb.

[gsxrpilot]

I'm instrument rated and use it regularly. I've got the STec30 and LOVE it. I often climb into the soup 400 to 600 ft. off the deck. I can flick the autopilot on even in a climbing turn and then just let it do it's thing. All of a sudden, all I'm doing is managing altitude and talking to ATC. When I go out a practice, I do half the work with the autopilot and half without. I think it's just as important to know how it works, how to monitor it and how to trust it, as it is to know how to fly IMC without it.  I can't imagine having a Mooney without an autopilot. It just makes it so much more useable and pleasurable to use.