ILS in AH

[Gunner 69]

Hello Gents and Greetings,

I found here some recent activity regarding Air Hauler, so maybe someone could help with an ideea. For me, ILS is not working in AH. It goes fine if i'm in a freeflight, with plain FSX. I'm having fun with AH for more than a year now, but this issue just came up, as i had no ideea how to use ILS till now and was always landing manualy . Lately had figured out the ILS landing proc, so i said , lets go to jets and haul some serious cargo. I can safely land those too manualy (most of the time, lol ), but its bugging me, what could be wrong. Basicaly, when i intercept the localizer (that one is working) and starts turning the plane to line up with the RW, the Altitude hold also goes off, even i'm well bellow the glideslope, then the plane dives toward the ground or if its empty its pitching up. The AP is working well until i reach the range of the ILS. Tried to approach with higher speed, same thing, at 190 kn the plane starts "loosing" the glideslope and descends faster, only solution to disengage the AP, and "recover" manualy. This was Thomas Ruth-s A 330. Was suspecting the cargo weight, as it seems that if the cargo exceeds the "full tank + cargo capacity", using let's say 30% fuel, the plane behaves like its overloaded, comparing the trimming used by the AP in AH and freeflight. But the same happens with no cargo and with remaining fuel for about 30mins. As i said, in freeflight its working as it should, with full payload and fuel, max. Grossweight. I'm "flying" with mouse yoke, no pedals, my FSUIPC its unregistered version, never touched the settings part. So , if anybody have any ideea where should i look, please share :smile: .

thnx

Regards, G

[allardjd 1,853]

Gunner,

I don't know of any way for AH to affect the operation of the autopilot, however center of gravity from non-optimal cargo loading is one possibility here.

 

You don't say if the aircraft has autothrottles or not and that could complicate things. If not, then all the AP has for following the glideslope is pitch trim - it's all it can do.

 

If the altitude hold is disengaging early, before the glide slope intercept, that's certainly a problem but even then, it should try to climb to the glide slope in that case. Throttle settings are up to you unless there is an autothrottle feature.

 

By way of testing I would set up a flight and very carefully watch two things - airspeed and pitch trim setting. Is the AC running out of pitch trim? If pitch trim is running into the limit of its travel, then loading is part of the problem. Is the airspeed falling off and causing a stall? If that's the case, push the throttles as much as needed to keep the speed up. Remember, all the autopilot is doing is following the localizer and using pitch trim to try to get to and stay on the glide slope. You have to use the throttles to keep the airspeed where it should be when the AP is coupled.

 

The unregistered FSUIPC is all you should need, but be sure it's the latest version.

 

John

[Gunner 69]

Hy John, thnx for the fast reply ,

all ILS approaches was made with autothrottle. The problem is that in the moment i intercept the localizer and the HDG goes off, the ALT HOLD also goes off, even i'm bellow the glideslope and there is a 4-5 nm to travel to cross it. It does not try to catch the glideslope. As i mentioned before, this happens only in AH, in freeflight it works az it should. So far i tried with 2 jet engine AC, same happens for both. The plane does not stall or fall, it just disables the ALT hold and pays no attention for the glideslope (it gets and keeps the localizer though).Will try tonight with my trusty 208B, see what happens. As for the pitch trimming, for a , let's say 60000 lbs load and 40 % tank, in freeflight the AP trimms the elevator for about 3-4 degrees , in AH same plane, same load , trimms for 9-10 degrees (this for a plane with a max. pitch trimm limit at 15 deg). Did'nt noticed so far, as i had no problems for manual approach and landings. Does anybody knows any third party AP, what i can try?

Regards,

[allardjd 1,853]

A third party AP won't help - all they do is call the same routine in FS.

 

I'd look in the FS Fuel & Payload menu after AH loads a cargo and see WHERE it's putting the cargo. AH is sometimes pretty stupid about where it puts the weight, often putting tons of it in the co-pilot's seat. It's wise to always look at the weight distribution before taking aff on an AH flight.

 

I don't fly airliners so am not too familiar with the procedure for them, but the reference to "...the HDG goes off..." is confusing to me. Do you not manually press the APCH button to couple up to the ILS? I guess if I'm using HDG mode to intercept the localizer that light does go off when I press the approach button, but typically, if Altitude hold is set, it should stay set until reaching the glide slope intercept.

 

I use ILS approaches frequently in FS/AH and have never had that problem. I'm inclined to say the altitude hold problem may be related to the AC itself, but not sure at this point.

 

Check that loading, however.

 

John

[Tim_A 997]

With autopilot problems, the usual suspects are auto throttle, trim setting, and balance. If the plane is out of trim when you engage the autopilot, on some aircraft FS will immediately return it to that trim state when the AP disengages, which is effectively like yanking the stick back, and that will cause altitude hold to disengage. The same is true for weight & balance. If you let AH load the plane with no thought to cargo position, it can easily push the CofG way out of limits, and that will have the same effect as a good thump on the nose or tail.

[Gunner 69]

Hey guys,

its working !!! Thank you both. After I kicked out a 36459 lbs. copilot , things started to get slowly on normal . Now i'm thinking, that probably the trimm was almost at max. and in the moment the Ac started to turn to the localizer, it runned over limit and disabled the ALT hold. Anyway thnx a lot , you guys saved me , i own you a beer .

Happy landings