Trouble landing Carenado King Air C90B

[jerdawg]

I'm having a lot of trouble trying to land this plane. I have only flown it twice and both times coming into the airport the plane starts to pitch up and down quite a bit even when still in autopilot......this starts about a mile or so from touch down.
I tried it again this afternoon trying to use autopilot as long as I can. The minute it started to pitch up and down I disconnected the AP and struggled to keep it straight and steady. I finally made it over the tarmac but the plane then slammed into the ground and crashed.
I am keeping my speed around 100 knots, flaps down, etc. but so far nothing seems to help.
I heard of a bug that you have to control (something about Vaccumm if I can remember right) otherwise it will do funny things but I have a set key binding for that.
I also have the B1900D and have problems with that as well.
Are all Carenado planes just hard to land or could I being doing something drastically wrong?
The you tube guys seem to do ok!
I really like the plane; just want to land it.
Thanks for your help!

[John W]

Don't know. When you select the aircraft for the flight go in to Weight, Balance & Fuel and click the restore defaults. Then try the flight.

[jerdawg]

Originally posted by John W:

Don't know. When you select the aircraft for the flight go in to Weight, Balance & Fuel and click the restore defaults. Then try the flight.

Well, I finally did it! Not sure what I did right this time John, but when I clicked off A/P it held steady. I'm going to try another flight and see if I can do a repeat,
Thanks for hanging in there and trying to your best to help out. I really appreciate it from all of you! This is why I love flight simming!

[John W]

Glad to hear it worked out. Happy Flying!

[fortunjj1]

Generally it makes sense to disable the yaw damper before landing. If you don't, you will be fighting the control system while under manual control. One thing about the elevator trim... do you have it set to an axis? If you do (as I do), when you try to adjust the trim manually, the plane will jump - reflecting the difference between the trim setting of the autopilot and the new setting commanded by the axis. The answer to this problem would be to make sure that the axis trim setting is equal to the current setting before you disconnect the autopilot. IIRC, it is possible to view the axis value independent of the current trim setting. I'll try that out and report back... it might help if this is what is happening in your case. The same problem occurs with planes that have an autothrottle.

Edit: It doesn't help much to know the axis value. Of course, if you adjust the trim manually while using the autopilot, the autopilot will adjust accordingly and you end up chasing the autopilot with the manual trim. For this to work, you would have to disconnect the manual trim, align the axis and then reconnect the manual trim. I guess it is better then to have the trim adjusted incrementally rather than from an axis - which is what most people do. I use the axis just so I can more quickly adjust the trim.

[John W]

Originally posted by fortunjj1:

Generally it makes sense to disable the yaw damper before landing. If you don't, you will be fighting the control system while under manual control. One thing about the elevator trim... do you have it set to an axis? If you do (as I do), when you try to adjust the trim manually, the plane will jump - reflecting the difference between the trim setting of the autopilot and the new setting commanded by the axis. The answer to this problem would be to make sure that the axis trim setting is equal to the current setting before you disconnect the autopilot. IIRC, it is possible to view the axis value independent of the current trim setting. I'll try that out and report back... it might help if this is what is happening in your case. The same problem occurs with planes that have an autothrottle.

Edit: It doesn't help much to know the axis value. Of course, if you adjust the trim manually while using the autopilot, the autopilot will adjust accordingly and you end up chasing the autopilot with the manual trim. For this to work, you would have to disconnect the manual trim, align the axis and then reconnect the manual trim. I guess it is better then to have the trim adjusted incrementally rather than from an axis - which is what most people do. I use the axis just so I can more quickly adjust the trim.

i'm not sure where you're getting your information. On the B1900D, C90B and B200 aircraft, when you manually adjust trim it disconnects the autopilot. The trim should not be assigned to an axis. I use a castle switch on my throttle control. The hat switch can be used as well. Modify the hat switch settings, use custom, and select pitch trim up for hat up, pitch trim down for hat down, roll trim left for hat left and roll trim right for hat right. For the up left, up right, down left and down right set them to do nothing. This works very well.

I'm fortunate in that my flight system (T1600M with throttle and pedals) has two hat switches and two castle switches. I use one castle switch for pitch and roll trim, one for preset views, look left, right forward and external. If you don't have a spare castle switch or hat switch then you would need to program buttons on your controller for pitch trim up and down. By default the keyboard [ and ] are programmed for pitch trim up and down.

[fortunjj1]

Agreed John, it should disconnect the autopilot - but it doesn't. I tried it just a few minutes ago. I could adjust the trim and the autopilot would correct for my trim adjustment without disconnecting. Give it a shot on your setup using the trim switch. Perhaps this is a bug...

You are also correct that it is best to use a switch for the trim because it is incremental from the current value as opposed to absolute. There are trim wheels that you can buy that are assigned to an axis so I wasn't sure what the OP was using to adjust trim. Based on the jump when disconnecting the AP I thought it might be assigned to an axis. Again, I sometimes just use the wheel at the side of the T1600M for the trim. It creates the exact problem I described and it isn't realistic but it allows for fast adjustment of the trim. I also use one of the castle switches on the left of the T1600M for pitch trim.

Edit: Yep - a bug. If the trim is assigned to an axis, it doesn't kick off the AP. A trim switch does.

[John W]

Unfortunately I don't have the Carenado C90B to test but I do have the B1900D and B200 King Air and they both disconnect the autopilot when the trim is touched. I'm wondering if something isn't configured correctly which is causing the autopilot to not disconnect with a trim input.

[jerdawg]

Originally posted by John W:

Unfortunately I don't have the Carenado C90B to test but I do have the B1900D and B200 King Air and they both disconnect the autopilot when the trim is touched. I'm wondering if something isn't configured correctly which is causing the autopilot to not disconnect with a trim input.

I'm not sure......just crashed it again going into KJAC. I'm about to give up on this thing.......lol.

[John W]

OK so what happened? How are you controlling your elevator trim? Are you using a joystick profile. What joystick/controller are you using? Is this only happening after disconnecting the autopilot? What if you fly an approach without using the autopilot? Can you control the trim?

[jerdawg]

Originally posted by John W:

OK so what happened? How are you controlling your elevator trim? Are you using a joystick profile. What joystick/controller are you using? Is this only happening after disconnecting the autopilot? What if you fly an approach without using the autopilot? Can you control the trim?

I'm using a thrustmaster hotas 1600m and I have the trim profiles on the top left and right joystick buttons by the hat switch.
Yes it only happens when I disconnect .
I always disconnect A/P without hitting the approach button on autopilot.
I just tried flying the B1900D now which I had trouble with also, but this time I tried using approach on autopilot and by God that worked!
I'm still a novice so I know I have to learn alot still.
Does the approach on the A/P work for ILS and Rnav approaches?
Usually if I disconnect autopilot I have to fight it to stay stable while trying to adjust trim.
Earlier with the C90B it practically went into a nose dive but I saved it.....maybe it has a bug?

[John W]

So on the T1600M you are using buttons 7 and 8 with the default profile. Do you have anything else configured for pitch trim up and down? Also, let me ask this.

the autopilot will work with ILS approaches and RNAV approaches that have a glide path. Not all RNAV approaches have glide paths. Also on RNAV approaches you have to manually descend the aircraft to make altitude restrictions until you intercept the RNAV glide path. Once the autopilot intercepts the glide path it should descend the aircraft.

[jerdawg]

Originally posted by John W:

So on the T1600M you are using buttons 7 and 8 with the default profile. Do you have anything else configured for pitch trim up and down? Also, let me ask this.

the autopilot will work with ILS approaches and RNAV approaches that have a glide path. Not all RNAV approaches have glide paths. Also on RNAV approaches you have to manually descend the aircraft to make altitude restrictions until you intercept the RNAV glide path. Once the autopilot intercepts the glide path it should descend the aircraft.

Yes buttons 7&8.
I dont think I have anything else for trim but I will check.
On the hotas throttle I was wondering if you can map the paddle type lever for trims?
What do you use for a flight stick?
I really never looked much into altitude restrictions much, but I should because I need to do it right.
I have just been looking at the charts to see what waypoint the glideslope starts at and then set the vnav for that altitude.
What is your procedure?
Thanks for the help...
Just started messing with the GA aircraft in my hangar again...

[fortunjj1]

You don't have trim set to an axis which is good. Therefore there should be no jump when the AP is disconnected. If it jumps, see John's suggestion of something else controlling the trim above. If the C90B nose dived without you commanding it, I would say you were too slow - or something else was controlling the trim. Note that you can display the trim setting on the screen. That might help troubleshoot a trim problem.

The C90B is relatively stable, IMHO. In fact, as I mentioned before, it feels sluggish and slow to me. It is hard to get it to do anything quickly. But you do have to keep it trimmed. If not, it will continue going where it was going - and that could be nose down...

If I could offer a suggestion about using ILS approaches... It wasn't all that long ago that I relied on the glideslope for all approaches. Now, I never use it. I always disconnect the AP below 1500 feet or so. This allows you to get a sense of how to use the throttle to control the rate of descent with the pitch adjusted to maintain airspeed. Once you have mastered this, you will be ahead of the airplane whenever you disconnect the AP and not feel like things are out of control. It is this skill that you see exhibited on youtube when people execute smooth landings.

The C90B from Carenado is fun to fly once you get used to the feel of the plane. It slows down easily and doesn't have many quirks in its behavior. Assuming that the trim isn't borked somehow I would think that most of your difficulties can be rectified by spending more time with it.

[jerdawg]

Originally posted by fortunjj1:

You don't have trim set to an axis which is good. Therefore there should be no jump when the AP is disconnected. If it jumps, see John's suggestion of something else controlling the trim above. If the C90B nose dived without you commanding it, I would say you were too slow - or something else was controlling the trim. Note that you can display the trim setting on the screen. That might help troubleshoot a trim problem.

The C90B is relatively stable, IMHO. In fact, as I mentioned before, it feels sluggish and slow to me. It is hard to get it to do anything quickly. But you do have to keep it trimmed. If not, it will continue going where it was going - and that could be nose down...

If I could offer a suggestion about using ILS approaches... It wasn't all that long ago that I relied on the glideslope for all approaches. Now, I never use it. I always disconnect the AP below 1500 feet or so. This allows you to get a sense of how to use the throttle to control the rate of descent with the pitch adjusted to maintain airspeed. Once you have mastered this, you will be ahead of the airplane whenever you disconnect the AP and not feel like things are out of control. It is this skill that you see exhibited on youtube when people execute smooth landings.

The C90B from Carenado is fun to fly once you get used to the feel of the plane. It slows down easily and doesn't have many quirks in its behavior. Assuming that the trim isn't borked somehow I would think that most of your difficulties can be rectified by spending more time with it.

Thanks....you guys are becoming my Mentors!
I will check out for displaying that trim setting.
How long have you been flying....or are you a real pilot as many are in here.
Thanks for the great information....I am absorbing it all like a sponge!

[fortunjj1]

Not a real pilot - just have about 700 hours in X-Plane and a few hundred in P3D. The C90B was one of the first planes I bought for X-Plane. For now, I'm not too big on procedures. My thought was that they will make more sense once I can fly the plane. I have used ILS with the glideslope quite a bit in the past as I mentioned, but TBH it got a bit boring and I wasn't spending enough time flying. My knowledge of the g530 isn't much beyond the basics so I can't offer much help with RNAV and LPV approaches using the GPS. My preference right now is to use the g750 whenever I can anyway. The g1000 would be the next thing to tackle. I do prefer GA flying at present, so most of the 700 hours was in GA planes. I agree, there is a LOT to learn.

As a reference, I bought X-Plane 11 in the middle of 2017 but I have used flight sims (Microsoft FS series up to P3D and even earlier when I was in high school, subLOGIC flight simulator II circa 1985 or so on my Radio Shack Color Computer II) for a long time.

One other thing about procedures... I think what would help most with procedures is Pilot2ATC. I have it, but I'm just not there yet - I'm still learning how to fly a plane!