ANSWERED automatic approach misdirecting plane

[Rodger Pettichord]

Hi. A quick question. As often as not, the automatic approach button is misdirecting the plane when engaged. Usually, it is sending the plane low and to the left of the runway. This happens in both the full-package scenery and in the Global general scenery. Is this a fixable problem? (On the other hand, I'm getting pretty good at hand-landing all kinds of planes in all kinds of weather)

[Adam Banks]

Have you got "gyro drift" enabled in your realism options? If so, you'll need to re-align with the "d" key.

Some aircraft - particularly the later A2A/Accusim GA ones - suffer a bit when the system is under heavy load. Apparently the FSX flight model gradually degrades and the autopilot struggles to make the necessary corrections.

Does it happen with all aircraft and all ILS airports?

Adam.

[Wolter van der Spoel]

Adam is spot on, use the "Delta" and "Bravo" keys to readjust Altimeter and Compass

[Adam Banks]

Thanks, Wolter - I forgot to mention the "Bravo" (altimeter) key. It's become second nature to me over the years as I always "fly" with dynamic weather enabled and baro pressure can often change slightly during a long descent. OPUS has a setting to filter this out, but I still keep thumping those keys just in case!

Adam.

[Stewart Hobson]

Have you got "gyro drift" enabled in your realism options? If so, you'll need to re-align with the "d" key.

Some aircraft - particularly the later A2A/Accusim GA ones - suffer a bit when the system is under heavy load. Apparently the FSX flight model gradually degrades and the autopilot struggles to make the necessary corrections.

Does it happen with all aircraft and all ILS airports?

Adam.

I've had trouble making an ILS approach to North Bend Muni KOTH in the A2A C172.  The autopilot set to APR had no problem finding the center line of the runway, but had trouble with the glide slope.  OTOH, I made a very nice instrument approach to Campbell River, BC, CYBL, in the A2A Cherokee with no problems.  Go figure.

 

Stew

[Adam Banks]

I've had trouble making an ILS approach to North Bend Muni KOTH in the A2A C172.  The autopilot set to APR had no problem finding the center line of the runway, but had trouble with the glide slope. OTOH, I made a very nice instrument approach to Campbell River, BC, CYBL, in the A2A Cherokee with no problems. Go figure.

Stew - go check the A2A forums. There's been a lot of discussion about this issue. I found that even when the a/p behaves normally, it's critical with the C172 to keep airspeed at a constant 65-70 knots and to not "follow the needle" too much. It settles down after a while and tracks the g/s OK.

Adam.

[Stewart Hobson]

Stew - go check the A2A forums. There's been a lot of discussion about this issue. I found that even when the a/p behaves normally, it's critical with the C172 to keep airspeed at a constant 65-70 knots and to not "follow the needle" too much. It settles down after a while and tracks the g/s OK.

Adam.

Adam,  That makes sense.  I tend to enter the approach a little faster than I should, so that could be a factor.  Also, I wonder if my 3000' altitude when I started the approach might have had something to do with it.  I did not follow the needle on the two approaches I made--I allowed the autopilot to steer the airplane, as I thought that was how one does an instrument approach.  Then at the decision height, take over control of the airplane for the final 300 or so feet.

 

Stew

[Adam Banks]

Adam,  That makes sense.  I tend to enter the approach a little faster than I should, so that could be a factor.  Also, I wonder if my 3000' altitude when I started the approach might have had something to do with it.

That does sound a bit high. I think common practice is to intercept the G/S from below. Normally, I'd be well established on the localiser at 2,000ft or 2,300ft, flying straight and level until just a tiny bit before the G/S indicator reaches the marker.

Maybe you're over-speeding a bit as you're having to lose all that height <?>.

Somewhere on the A2A forums, there's a really interesting post from a RL pilot, saying (in effect) that the RL a/p is nothing like the "fly-by-wire" PC sim equivalent. ie. A lot more finicky/complex. Maybe A2A are the first ones to model it with such fidelity and it's catching us armchair pilots out!

Adam.

[Stewart Hobson]

That does sound a bit high. I think common practice is to intercept the G/S from below. Normally, I'd be well established on the localiser at 2,000ft or 2,300ft, flying straight and level until just a tiny bit before the G/S indicator reaches the marker.

Maybe you're over-speeding a bit as you're having to lose all that height <?>.

Somewhere on the A2A forums, there's a really interesting post from a RL pilot, saying (in effect) that the RL a/p is nothing like the "fly-by-wire" PC sim equivalent. ie. A lot more finicky/complex. Maybe A2A are the first ones to model it with such fidelity and it's catching us armchair pilots out!

Adam.

I wouldn't doubt that that is true about A2A's more accurate a/p.  I will try that approach again lower and slower and see what happens.  I may have lucked out on the first try with the Cherokee, which is a sweet little airplane in any case.

 

Stew