Knowing your autopilot

I press the CWS button before (first) engagement of the AP in initial climb, to make sure it takes the pitch I currently want instead of anything that might still reside in a transistor from the day before. Yes, there is a self check, but nevertheless.

It does not, though, allow me to fly 360ies. The King KFC150 CWS does give you the plane completely when you push the button, you can turn and do what you want, however if you release it and the HDG mode is active it will immediately turn back to the original track

From here

Mooney_Driver wrote:

The standard procedure for this (disconnect the AP and get the airplane levelled out with wings level) will not always lead to something nice either as the AP may very well be doing something quite reasonable while the pilot is way behind the airplane and has no idea what really should be done next.

Which is why some folks who are active on COPA are pushing for a change in procedures in these “what’s it doing now?” moments. They advocate against going from full coupled flying on autopilot to full manual flight, which can easily leave the pilot stunned and overwhelmed as he then has to not only figure out the issue which caused the deviation from the intended flight path, but also manually fly the plane. Most often, it’s a wrong setup in the nav box, like activating an approach which then sends you to the IAF, or being in the wrong mode (GPS or VLOC), etc. But it rarely is an electronic or mechanical problem, where you might actually benefit from hand flying (and where the autopilot should itself detect the error and disconnect).

So the advice is to gradually go back one level of automation, e.g. from NAV mode to HDG+ALT, and also to incorporate the “Straight & Level” button of the DFC90 and GFC700 into your decisions. That way, you can stop the plane from doing something that you don’t understand while still having the capacity for checking your nav setup.

What rwy20 says. The best procedure I know in these cases is tio kill all the autopilots modes, to center the herading bug (if not already so) and proceed with HDG+ALT. many newcomers have little idea about all the fancy autopilot modes, and while a lot of the possibilities are really cool they can get the beginner in real trouble.

The “back to IAF” trap is very typical. Many pilots (first) think that while they’re on vectors they have to “activate” the approach in the navigator. I only do that while in a hold at the IAF. To get out of the hold I activate the approach and the sequencing via the IAF starts. In all other cases (and I mostly fly RNAV approaches) it’s much better to load the approch and simply proceed to one of its fixes,… than the FAF. Because that’s the next trap and many times it’s caused by ATC who give you a direct to the FAF. The autopilot will capture the ILS localizer or GPS final track but never capture the (virtual) glide slope. That’s why I never accept a direct to the FAF in IMC. In don’t care in VMC.

There’s more stuff like that and it can take years to really understand the behaviiour of both the A/P and the navigators. It doesn’t help that most manuals are substandard.

dylan_22 wrote:

What rwy20 says. The best procedure I know in these cases is tio kill all the autopilots modes, to center the herading bug (if not already so) and proceed with HDG+ALT. many newcomers have little idea about all the fancy autopilot modes, and while a lot of the possibilities are really cool they can get the beginner in real trouble.

Yes while I agree that goingback to HDG and ALT is a good idea, if you are a newcomer who has no idea about these modes you shouldn’t use them. These days with the internet and fora like here, there are plenty of ways to learn beyond just reading the manual. But I do agree, if the vertical side is Ok ie you are level and the aircraft turns in a way you didnt expect, sync the heading bug and go to heading.

This thread defies belief. Sorry to say that. “Pilots” who do not know which mode their autopilot is in (or even worse: who do not know where to look which mode is currently active) should either not use that device, read the manual of have someone explain it to them. And that one is supposed to switch the autopilot to a “lower level” before turning it off is one of the most stupid things I have ever read on the internet. I would love to see that being done in the one situation where (my guess) statistically most autopilots get switched off most often: At minimum on a coupled ILS approach…

“Pilots” who do not know which mode their autopilot is in (or even worse: who do not know where to look which mode is currently active) should either not use that device, read the manual of have someone explain it to them.

@what_next, while I agree with your above sentence I disagree with the rest. What I have seen commonly is someone is flying an LNAV route on A/P and loads an approach. They are flying along in NAV and the controller tells them after waypoint XYZ cleared for the approach so they go and activate approach. This then turns them to what could be, for them, a random IAF. They disconnect the autopilot and end up in a mess.

Of course it shouldn’t happen but in that scenario going to HDG mode is the simplest and safest while they sort themselves out. After all part of the reason we all sync the heading bug is to allow this recovery mode.

From what i have seen people do, the best way into this mess is to forget the Transition button on the GTN. They have loaded and possibly activated the approach, but left the Transition set to Vectors. They are then cleared for the approach and their understanding of what’s going on diverges from what’s in the Flightplan page, and it starts going downhill from there.

Under those circumstances it makes most sense to go into HDG and ALT and turn the bug towards the IAF, rather than disengage and having to focus on the aviation ahead of the navigation and communication, then sort out the programming before re-engaging NAV or roll-steering.

If this is really one of the stupidest things what_next has read on the internet, he has had a very sheltered life. Perhaps I can recommend some sites? Chemtrails, UFOs and religion are good places to start.

I have been at FL280 past Belgium inbound to London. In the Meridian the G1000 didn’t load all of the waypoints in an airway that was loaded. I got direct to xxxxx and made a mistake in entering it out of sequence. As I was already on the airway the screen showed a straight line but the route involved a waypoint then a 180 back to the earlier waypoint then a 180 to the nxt in sequence. All of a sudden the plane when I was expecting nothing turned left. I hit HDG and realised my mistake. There was no need to disconnect the A/P.

what_next wrote:

This thread defies belief. Sorry to say that.

I suppose you mean the old one, from which this was split?

“Pilots” who do not know which mode their autopilot is in (or even worse: who do not know where to look which mode is currently active) should either not use that device, read the manual of have someone explain it to them.

Who has suggested such? I think you misunderstood what was written. If you consciously go back from NAV mode to HDG, then at no point did you “not know which mode your autopilot is in”.

Obivously, this doesn’t concern skygods and Chuck Norris, who don’t need to follow the flight director because the flight director would follow them. For all others, I liked the idea being brought forward by the folks on COPA. I do have a feeling that those people who will slag this new idea off on forums for a few years now are the same who have argued against the use of a parachute and would prefer to have private pilots die in style rather than save their a** and admit to a mistake. But frankly I don’t have any skin in the game, I just like the idea and I’m sure it will be thoroughly debated and those parts that prove to be worthwile will be implemented by Cirrus instructors.

And that one is supposed to switch the autopilot to a “lower level” before turning it off is one of the most stupid things I have ever read on the internet.

Here, you clearly misunderstood (or are deliberately misquoting?) what I wrote. If you get into a situation where your plane does something which you don’t understand, whilst on autopilot, then you shouldn’t throw your automation out of the window altogether. At no point was there a suggestion to make this a general rule, to always go back from NAV to HDG to ROL to Straight & Level before you think about turning your A/P off (e.g. at minimums). Obviously that would be a stupid way to handle the transition of control. When the pilot decides to take control from the A/P, then it is just like taking control from another pilot. It is a prepared and deliberate action.

I would love to see that being done in the one situation where (my guess) statistically most autopilots get switched off most often: At minimum on a coupled ILS approach…

If your autopilot happened to start turning in an unexpected direction while you fly an ILS close to minimums, then yes, on a modern plane like an SR22 with Perspective avionics and go around button, your safest course of action would be to press said button while advancing the power lever, which would switch back to GPS, activate the missed approach segment, G/A mode with 7.5° pitch up attitude, and automatically fly you to safety. No need to disengage everything and go back to complete hand flying.

After minumums, you’d obviously already be hand flying. In that case, you’d also press the G/A button, verify your flight director and then quickly switch the autopilot back on. But I think you must have somehow misread what I wrote.