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LNav degraded after CRJ update patch


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I put on the Aerosoft CRJ update patch today and I now see a poor LNav performance. Before patch all was fine?

Specifically, aircraft rolling constantly as it "hunts" for the FMS track?  

Progress page shows XTK varies R and L over 1 NM as aircraft rolls left and right!

Very unpleasant to fly now. 

 

Selecting HDG mode and all is well again. 

 

It looks loke the fault was in the FMS?

 

In STAT page I see a "wing cowl A/I on", green message? Never seen that one before...does that make a difference?

 

Winds were steady at 26 knots, 17 knot headwind, 18 knot crosswind.

 

Thanks.

 

 

 

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  • Deputy Sheriffs

The anti-ice should not make a difference. You can turn that off on the right side of the overhead (just above the window heat and probe heat switches). We'll try to have a look if there is a way to improve the LNAV in due time. We are aware that in some cases it tends to search for the right track with left/right movements.

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I second this, It's like the plane isn't flying with a WCA so on this flight I had a strong crosswind from the left resulting in the autopilot doing this S-shape flying constantly to "get back" on the track. Shouldn't it fly with a win correction angel instead?

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OK, so I re flew the exact route. EGCC EGKK with same SimBrief flight plan, but an hour later. So had slightly different wind conditions, as SimBrief updated the weather for the FMS download.. (MSFS Live weather)

 

I had no problems with the FMS following the route, for the second flight? The wind was almost identical.

 

I have flown the CRJ in P3d for very many hours and in MSFS this is my favourite aircraft. So I am familiar with its systems.

 

I must conclude that it was an Asobo Glitch that caused the aircraft to fly so poorly, as a one off? 

 

The only other thing I'd mention is that on both occasions, I saw the aircraft fail to turn left (south) onto the SID (LISTO2Y) after taking off from 23R at EGCC. The AP was put in at 1700'AGL and commenced a climb to selected altitude 5000' on speed mode, at 195 knots. But the LNav remained at runway heading until I forced a Dirto HON. Thus circumventing the SID? This happend on both flights.

 

Ill do some more flying and see if I can reproduce. But the winds are light at the moment over EGCC.

 

Cheers.

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2 hours ago, Yvan Duong said:

I'm experiencing this issue as well since patch flying westbound, but initially northbound. Will need to fly more and see if it continues to behave the same way

 

Ive re-flown the route 4 more times. Once in the FBW Neo, to compare accuracy!

 

Im getting consistent route following with the FMS now. I have a 20 knot X-Wind component. It seems OK.

 

Two more issues have surfaced however.

 

In the climb out from EGCC to 5000' (first SID constraint), the aircraft will consistently overshoot the altitude constraint. Going to 6000'++. This is with Speed climb mode and speed set at 182 (+10 Vref) P2ATC gets upset!

 

Also in the climb out, after AP select on, unless I select NAV twice ( deselect and reselect) the aircraft flies runway heading and wont turn to the first SID WP..(MCT DME2...LIST2R-RW23R, SID) I select NAV mode on the runway prior to roll. 

 

But at least the aircraft will follow FMS route. I am flying a southerly track, I havn't tried any other directions, so dont know if its compass related or not?

 

Cheers.

 

EDIT. Finally, at EGKK I couldnt get the aircraft to track the ILS. Freqs were correct and I had LOC/GS on PFD, but the landing path veered off to the left of RW26L and no GS capture. I went around but saw that I couldnt de select the APP mode switch, it stayed illuminated. Further attempts to land with ILS and AP were futile. So I surmise my PC is having a bad day, Im having a bad day or since the update patch something has changed. Ill try other airports and flight tomorrow.

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On 31.3.2021 at 21:51, herky20 sagte:

In the climb out from EGCC to 5000' (first SID constraint), the aircraft will consistently overshoot the altitude constraint. Going to 6000'++. This is with Speed climb mode and speed set at 182 (+10 Vref) P2ATC gets upset!

Your first issue, the altitude constraint, happens often to me, when engaging AP during or just before the ALTS CAP phase, I've also recorded videos. My current workaround is to engage AP earlier. By the way, you might know, we can edit the altitude tolerance at P2ATC settings, I use 200ft because of manual flying a lot.  

Regards, Herbert

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I have this „left and right“ problem also. In short, right turn ahead, plane will fly right a bit early, then do a hard turn to the left to catch the route path again then doing a hard right turn to stay on that track. Kinda weird as i only have it in the crj atm.

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At the moment, patch 1.0.0.1, I only have issues when the CRJ is attempting to fly a SID. Its reluctant to auto update to the next WP in the SID. It requires multiple Dirto corrections anf repeated Nav pushes?

 

Thanks

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Yes actually, the LNAV autopilot is really bad.

 

On my experimental flight from LSGG-RWY04 to LFML-31R, my plan have to do a U-turn after takeoff. But the aircraft is not able to calculate the required radius to make the U-turn. It fly a much steeper turn, then want to go straight, but change its mind, start trying to catch the path and so on... Later on in the flight, it oscillate over the path almost 5-8 times, to be, more or less at last, able to follow the path. But, if wind conditions change abruptly, bingo, again problem to follow the path !!!

 

It is now about on week (1 or 2 flight by day) I do this same training flight to lean this aircraft, but until now, except on time where I was probably extremely lucky, I wasn't able to conduct successfully, a full approach on the ILS path (with LOC and GS locked). Most of the time I miss the GS lock and this morning, for example, I was attentive to intercept first the LOC and be UNDER the GS at that point, but because I was focused on that, my speed was all wrong and even if the LOC interception occurred, here again, I had a lot of mad lateral oscillations, so, as usual, I had to take manual control much sooner than I wanted for my exercise.

 

Yes, this aircraft is really challenging, but not having an auto-throttle is really a bit too much to my taste !

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On 3/31/2021 at 3:51 PM, herky20 said:

In the climb out from EGCC to 5000' (first SID constraint), the aircraft will consistently overshoot the altitude constraint. Going to 6000'++. This is with Speed climb mode and speed set at 182 (+10 Vref) P2ATC gets upset!

By the time you get to 5000 feet, you should be flying at 230-250 knots, with the aircraft “clean” (flaps and slats fully retracted). 182 knots is fine for the initial climb phase after takeoff, but you need to accelerate above 1000 feet by pitching down to retract the flaps and slats. 

 

If you did retract both flaps and slats, and still have your climb speed set at 182 knots, that is probably part of the altitude capture problem. At 182 knots, you would need to have at least slats deployed, and if the aircraft is heavily loaded, flaps 8 as well. Without them, at 182 knots, the aircraft will pitch the nose too high, which would make it difficult to capture altitudes smoothly and efficiently.

 

The takeoff and initial climb technique I use is to retract the gear once airborne, and pitch to follow the flight director after takeoff until 400 feet AGL. Then I press the SPD button on the AP (which will set the speed bug to your current airspeed), followed by the HDG or NAV buttons, then engage the autopilot. Passing 1000 feet AGL, I then immediately dial the speed up to 230 knots. This will automatically start pitching the nose down to accelerate to the new selected speed. Retract flaps passing the blue “T” on the airspeed tape, then  retract slats passing 210 knots, and at the same time, pull the power levers back from the TOGA detent to the CLB detent. 

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