autopilot question in 172SP

[mcjohn]

I'm instructing in that same plane with all the KLN-94 moving map stuff and that same KAP 140. I can make everything work well enough to show a student all the basics. But half of it I have to admit to being unable to use. I found RipCurl's explanation of the two alt modes helpful.
I can bang on the face of that KLN-94 all day long......I've learned not to do that with the KAP-140 unless I want to put on unintended airshow.

Oh crap! I had to edit this in. I intended to tell the thread poster to look at the supplements in the back of the 172S POH. It's bar far the only practical explanation that walks you through some steps of the KAP140. The King Bendix guides are really weak. Especially for the KLN-94 (the only one I looked at.)

 

[Immelman]

Make sure you know how to disengage it - sounds like you already do. Make sure you know what it can do to pitch trim.. not a huge deal in a 172. Aside from that, just figure it out. They are pretty simple.

They are very useful for single pilot IFR, obviously. Worth their weight in gold. About the comments on hand flying all your VFR time building... ehh.. its a 172! If you want to be a better "stick" get some tailwheel time! I've flown one across the country and back w/o autopilot, no big deal. It was hands off most of the time anyways.. maybe use a pinkie finger to keep it level. Have fun.

 

[Kream926]

push the GPS button thats next to the annuciator pannel to slave NAV1 to the GPS then hit the NAV button on the autoilot, that should do the trick. if you want it to follow a VOR just skip step 1

 

[atldc9]

Read the supplement in the POH. It has normal, and non-normal checklists. You should be aware, there are specific limitations with regard to the AP, as well as required preflight checks prior to its use.

Make sure you truly understand how to turn the AP off, and where the circuit breaker is. If it is not doing what you want, or what you think you told it to do, pull the breaker and forget about it.

You should find another CFI as well. There is no excuse for giving an aircraft checkout and not knowing how to use something as serious as the autopilot. At the very least, they should have discussed the limitaitons and ways of turning the AP off, as well as preflight requirements.

 

[MauleSkinner]

BTW GoingHot -

I teach my private students how to use the AP in case they fly into a cloud. Sure, I teach them how to turn around with the attitude indicator, etc. But the way I see it, pushing that little AP button and then taking a deep breath might just save their life someday.

Just out of curiosity, what do you teach them to do next? Say, for instance, they go into the clouds because the clouds are getting lower than they want to fly...the 180 doesn't work in this case.

I ask because there was a student pilot a few months ago that got himself stuck on top of a layer...fortunately he found a hole and got down, but nobody I talked to had any real specific ideas for how to get him down if the hole wasn't there.

Fly safe!

David

 

[indianboy7]

Definitely learn the autopilot if you want to use it. The last thing you want to do is let that thing fly when you don't know what it's going to do. It's kinda like letting your dog fly while you take a nap.

Download the pilot guide and only mess with it in the airplane during vfr conditions at cruise while you're watching it like a hawk. It's an excellent tool, but only if you know how to use it.

If there's an instructor at the school that knows how to use it, see if you can go on a half-an-hour flight with them to learn the basics.

Also, if you're going to be earning any kind of license in that plane (instrument rating, commercial, etc. etc.), the PTS says that you must know how to use the automation. Some DE's ignore the autopilot for the same reason your checkout instructor did....they didn't know it themselves. Some other examiners go by the letter of the law and want to see it work.

Once you learn how to use the thing (and it really isn't that hard), it's great. It lets you spend your time looking out the window instead of inside the airplane. It also reduces fatigue....good stuff......good luck...

 

[minitour]

Just out of curiosity, what do you teach them to do next? Say, for instance, they go into the clouds because the clouds are getting lower than they want to fly...the 180 doesn't work in this case.

I ask because there was a student pilot a few months ago that got himself stuck on top of a layer...fortunately he found a hole and got down, but nobody I talked to had any real specific ideas for how to get him down if the hole wasn't there.

Fly safe!

David

The second best scenario I've heard in this case is to trim for best glide, take your feet off of the pedals and use the yoke to keep the wings level on the Turn Coordinator. Start walking power back slowly and you'll start descending at best glide...keep the wings level...who cares about heading!? When you pop out underneath, then it's time to figure out where you're at and fly the thing.

This is assuming you have a TC. I wouldn't trust an Attitude Indicator for a SP to use....they'd see the pitch and start correcting...stall....spin....bad stuff when IMC.

The first best scenario I've heard (in case anyone is wondering) is to:
1. Check the SP's flight plan for real when they go solo xc.
2. Teach them why IMC can be a PITA (by TAKING them into IMC as a student pilot...imagine that?)
3. Teach (there's that word again) them how to look at the weather forecast, what's happening outside their window, what they see going on and make a judgement of "hmmm.....maybe I should stay under that cloud layer I'm coming up on...the ride is bumpy, but at least I'm not stuck" to keep themselves out of trouble in the first place.

The last thing I want to do is teach a student that the Autopilot is there in case they get stuck IMC. Will it help? Maybe. What if it goes TU? Now they're in a turn or something with the AP engaged...once it pops off, they gotta recover. How much partial panel/full panel unusual attitude time do we typically give our instrument students? More than 3 hours....

JMHO

-mini

 

[jdlilfan]

I have over 150 hours or so in 172R's. Our flight school has the KLN-89B coupled with the KAP 140 single axis. The autopilot is very very simple to use but has a few quirks. The 172R POH has a great diagram of how the system works on page S7-6.

Some quirks I have found is that when shooting a GPS approach with the KAP 140 and there is a 90 turn to final. The autopilot is in the APR mode but will not turn with the GPS. The turn has to be led by the HDG bug which overides the APR/NAV mode until the intercept heading gets within about 30 degrees.

The same goes with using the NAV mode. Make sure that the HDG bug is set to the initial course otherwise the autopilot gets confused and sometimes turns or just follows the HDG bug while in NAV. Once the HDG bug is set to the NAV course and say the CDI starts moving or intercepting the NAV mode will then start following the needle.

Also when using the NAV mode in turbulence you have to be careful because big enough bumps will disengage it to roll axis mode or just make it confused and start randomly turning. The best thing to do is disengage/turn off the autopilot and turn it back on and set it back to NAV mode when back on course.

It did the random turns on me a few times in IMC on me while flying through some bumpy rain showers so you have to be quick to catch it and not get dissoriented when the plane starts banking right or left 30 degrees.



I learned a lot of this by just using the equipment and I was fortunate enough to have a knowledgable instructor when doing my instrument that showed me the ins and outs of the -89B and KAP 140. I am surprised at how many instructors don't know how the equipment works so then doesn't show the student. Then the student figures it out by themselves or finds out the hard way on a checkride. Some students I have chatted with only think that the GPS goes "Direct".

On my instrument ride I had to shoot an NDB approach using the autopilot. That was fun cause there was an annoying delay with the reaction of the KAP 140. He finally let me disengage it.

 

[yasir1212]

Hey guys,
A flight school next to mine just recently got a nice new shiny 172SP. It's a 2003 model i believe. I figured it'd be a good time builder and a nice fun and comfortable cross country aircraft with all of the bells and whistles. During the checkout we did the usual stuff until it was time to turn around and head back to the airport. I glanced down and noticed there was an autopilot. The problem was since that the aircraft was new to the fleet... neither i nor the instructor doing the checkout knew how to use it. I did fiddle around the altitude setting and got it to start climbing at 400ft/min but then we would've climbed into bravo airspace so i disengaged it. Then i tried to get her to maintain 2000ft altitude and to hold the flight plan on the GPS. It seemed like it was doing something but then it seemed liek it wasn't.

Anyone have any idea how to use that thing? The entire aircraft has bendix/king equipment including the AP.

By the way... any tips on transitioning to a low wing to a high wing aircraft? I've been flying low wings all through my training and flying a high wing seems wierd. The center of lift used to be right below me and now it's above me so when i'm turning instead of being near the pivot point on the axis it feels like i'm dangling there if anyone knows what i'm talking about.

thanks in advance

All 172SP's are equipped with KAP-140 Autopilots (different versions). Just takes a few minutes of reading the manual and "playing" with it in flight and it's a piece of cake. Just get the manual or look online and read it. Should be no problem at all, very easy to get used to. Get the manual for the GPS as well and learn to use both and you should enjoy the SP. I'm assuming it has a KLN-94 or a KLN-89B GPS. Either way, if you know how to use one, then you know how to use the other one as well, very very similar.

 

[RipCurl]

hmm... i think i actually get the altitude hold part.

Good, just be aware that if you are in altitude hold and you select a new altitude, it will remain in altitude hold at your current altitude with your new altitude armed.

When you say heading bug do you mean the heading bug that you can turn and set on the DG? Also... can you couple the thing to follow the GPS line? Is that possible?

Yes the heading bug is the little orange guy on the DG... the autopilot will follow it when in heading mode. To get it to fly your GPS course, make sure you are in GPS rather than nav mode, and then just hit the NAV button on the autopilot. You may have to set up an intercept (within 45*) for it to find the course.

 

[NoahWerka]

If you can't use all the equipment in the airplane to it's maximum capabilities, and can't fly the airplane within it's limitations (from one end to the other of the airspeed indicator and everything in between, and, know what you are doing) we will read about you in the papers, or see it on TV. Learn everything you about your aircraft so you won't be at a disadvantage when, not if, the poop hits the fan. A wise old pilot once told me that if you are farther off the ground than you would want to fall, the odds are against you. Your job as a pilot is to lessen those odds. Knowing everything you can about your aircraft lessens those odds. Keep that in mind and you may live to be an old, not BOLD pilot. If JFK, Jr. knew how to use the autopilot in his airplane, they wouldn't have had to dredge him from the bottom of the Atlantic Ocean.