I've an STEC 60-2, 3 axis auto-pilot. The manual (and POH supplement) has a list that seems it would take .5 on the hobbs to complete.

Sure, I can see that each controlled axis of movement needs to be assessed, but is there a quicker, more fluid approach that may be "standardized" or commonly done?

Bill, I've got a 60-2 but I'm not sure I understand your question.

The procedure listed for pre-flight check seems like it would take about a half an hour to perform. "Turn this on, set this heading, over-ride the forces, hit disconnect; set this climb, over-ride the forces, hit disconnect; and on and on and on.

Is there a standard quick check for multiple systems that's common among auto-pilot users?

Hi Bill

I looked at teh S-Tech POH to see what you were talking about. Heck, there's only 77 steps to complete!

If you cannot receive a VOR on the field steps 23-34 fall out, but can be done while enroute if you want to test it after takeoff. Depending on the presence of autotrim and a yaw dampener more steps are eliminated.

I would approach the preflight slightly different. I want to determine if the basic control loops work. Part of that is already covered in a standard check, Controls Free and Trim to Takeoff position, that you make anyway. By engaging the autopilot in Heading Mode, you can determine quickly if that is working correctly by moving the Heading Bug keft and right on the HSI (DG) and observing the yokes reaction. The Trim function and button can easily be checked as you run the Trim to the Takeoff position you would normally use. You test the Disconnect button at the end of each sequence. I don't think there is really much you can determine about the Altitude hold on the ground.

The short sequence above essentially lets you know the device's basic system is working properly. I would then feel comfortable with a normal takeoff and departure. I do not, and would not engage the autopilot until I'm 500' or so AGL and I might even wait until I'm further along in the initial climb to engage it if I am IMC. When I do so I'm expecting it to fail, no matter how extensive a check it has just passed, and watching it like a hawk for proper engagment. Only after I've watched it operate correctly for a few moments do I begin to relax a bit and start today's trust cycle all over. I'd follow this procedure whether I did a 2 minute test as described above or the 30 minute test you mentioned. I also then test other functions in flight, every flight, similar to the in flight mag checks many advocate.

I'm sure others may say you need to do more, and you may also feel the same way. In the end the proper thing to do is what gives you the warm and fuzzy feeling you need prior to pushing that first button after takeoff!

Bill,

I've got the 60-2 also, and one can get through the checks necessary to see if it will "get the job done" ie heading and pitch control, in pretty short order, once one has established a flow.

And, one could argue there's nothing wrong with doing the bulk of the checks airborne, assuming they've checked the disconnect features, and weather is appropriate.

Also, one could do all the checks on the ground and it could still quit after airborne.

Fortunately, it's a VERY reliable AP, mine has never failed, and as SOP, I do a minimum of checks before TO.

Thanks, Don!

That was what I was looking to hear; an abbreviated what NEEDS to be done on the ground. I can certainly do the rest in the air, as I verify each desired function for my level of "trust".

I just wasn't certain if there was a standard quick check that could be applied to "most" AP systems on "most" aircraft that saavy aviators did. A GUMPS version of an entire checklist, if you will

Thanks, Larry! I certainly know you to be one of those "saavy" pilots!

Hi Bill,

I had an S-Tec System 55 with Altitude Preselect in my Beech 18, and have a System 50 with alt hold in my P35 Bo at the moment. Had the same issue when I first got the Be18 as you do with the preflight checks.

Let me give you my perspective from having had a autopilot failure with the Be18. There is a nasty failure mode on the S-Tec system, and I found it. One of the turn coordinator outputs failed in such a manner that the autopilot made a full deflection right turn. Found it on the ground at Guatemala City, and my daughter and I hand-flew the Twin Beech back to Pittsburgh (via Key West).

So here's what I do. Turn on the autopilot, and use its self-test. After that has completed, I engage it in stabilize mode then heading mode and make sure its not headed off to the weeds. Does not take very long at all, then I put it back in standby. I don't test the pitch, or any of the over-ride stuff. But I do know exactly where the 3 ways to turn the thing off are. When I engage it IMC I put a good deal of attention on how it is working for the first little while.

Just my 2 cents.

Jay

Jay,

GOOD info, and I do essentially the same with the 60-2, but there's not a stab mode. Just select HDG and ALT, turn the heading knob and watch the wheel turn both ways. Disconnect. That tells me heading is working, ALT is holding, and disconnect works. Takes about 15 sec to do that.

I've also had a few exciting AP failures, and never did a preflight detect it. Also had a few runaway trim issues.... another fun time. Now the 60-2 has a trim option with and without AP input. Mine is without, which I prefer so they are two separate systems. And the light comes on if the AP is out of trim.... works really well.

I don't see much point in running any kind of pre-takeoff check on an autopilot unless it's required for the flight. Unlike engine and mag failures, an autopilot malfunction isn't going to ruin your day and there's at least as good a chance that it would fail after engaging it in the air as it would on the ground so you're not buying much. I run through those kinds of checks after any work is done that might affect the autopilot, especially work on the unit itself. I might consider a quick check of the heading function prior to launching into a 200 ft ceiling just in case things get too busy all of a sudden when I enter the clouds.

Heck IME 95% of autopilot "malfunctions" are just the pilot configuring the avionics incorrectly for the intended function. No 30 minute check of the autopilot operation on the ground is going to help there.

Now this is interesting...

From the deep recesses of my brain, I thought I remembered a regulation stating that if the AP was to be used in flight, it had to be tested prior to take-off. Maybe that was just that the disconnects were required to be tested prior to the flight...

I'll get to searching and report back...

Well... I'm back from the FAR's. And I'm happy to report that I can find no such regulation.

I could be remembering something that applied to 121 ops, or possibly prudent but not required pre-flight actions, or that if it's in the POH to check, it must be checked...
... or I could be just seeing smoke in my brain

Oh well, se la vie. I think I'll post the question on red-board. Should be fun to watch

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Works for me except you forgot to utter "What's it doing now?" in addition to the cussing on the lower branch.

I think the requirement for the test is contained within the Flight Manual Supplement from the manufacturer...

...in my case, I do as Lance does - engage the fool thing on the ground in heading mode, turn the heading bug to make sure it turns with it, and make certain that the disconnect button... disconnects.

ALSO, YOU DO KNOW WHERE YOUR AUTOPILOT CIRCUIT BREAKER IS, DON'T YOU?

As for me, I get the test sequence out of the way before I take off- on the 30, it goes through a self-test upon power-up, and since the servos engage momentarily during that test, you really don't want to do that during flight... or when you are doing your "controls free and correct" test pre-takeoff, lest you mistakenly believe that your controls are binding (ask me how I know this, heh-heh-heh).

On the 50, you have to put the power/test switch in "test" before it will allow the "ready" status.

Hey, Spike!

I'm thinkin' you may be right. Thanks for the post; and YES, I DO know where the AP CB is located!

Though, I have 4 ways of turning off an errant AP: 1. Yoke disconnect switch
2. Panel 'off' switch
3. Pull circuit breaker
4. Pointy toe on size 12 boot

One of'em ought to work!

Bill

I suggest you revise your flow diagram. Place Disengage Autopilot above Cuss. Its a matter of priorities!

OBTW, Bill, does this mean that you're flying again?

Please say, "Yes!"

This week!

I think that was Larry. I'm the one who tests upon engagement (like Mike B).



Yup, plus the five other ways to disconnect it. One thing I don't like is that my AP CB is on the lower right side below the panel and recessed back a bit. This makes it virtually impossible to see while sitting in the pilot's seat. I'm thinking of moving it to a better location.