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Glideslope oscillations


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Hello,

 

GS on autoland used to be rock solid, but since the last update it is a constant up and down (at zero wind) as the AP overcorrects each time up and down. Did anyone else noticed it?

 

Edited by oisin650
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I should've been more precise. Yes I know there is no full autopilot, but it happens on the approach even at 2000 feet. As soon as I disconnect at around 1000 feet it stops (while I fly it manually). So it happens as soon as the GS is captured.

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25 minutes ago, sztrova said:

I should've been more precise. Yes I know there is no full autopilot, but it happens on the approach even at 2000 feet. As soon as I disconnect at around 1000 feet it stops (while I fly it manually). So it happens as soon as the GS is captured.

Are you absolutely sure there is no wind?

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8 minutes ago, Prefect99 said:

Are you absolutely sure there is no wind?

I'm as the bouncing is gone as soon as I disconnect the AP and IU can easily follow the GS manually without these relatively big corrections. 

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1 hour ago, sztrova said:

I'm as the bouncing is gone as soon as I disconnect the AP and IU can easily follow the GS manually without these relatively big corrections. 

Can you provide an approach, weather conditions, and payload/fuel amounts, please? That’ll assist in reproduction.

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I did my first flight with 1.5.2 and observed the same thing.

ILS30 into ESSB
After GS capture autopilot continuously oscillates between 0.55 and 0.65 AOA.
Disconnecting AP immediately stabilises the descent.

ESSB METAR ESSB 031520Z 24008KT CAVOK 07/M08 Q1003

Never observed this before.

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36 minutes ago, marcvc said:

I did my first flight with 1.5.2 and observed the same thing.

ILS30 into ESSB
After GS capture autopilot continuously oscillates between 0.55 and 0.65 AOA.
Disconnecting AP immediately stabilises the descent.

ESSB METAR ESSB 031520Z 24008KT CAVOK 07/M08 Q1003

Never observed this before.

Thanks for the data, all helps! Please keep them coming. Any more examples @sztrova?

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Posted (edited)

Sorry, I had a family thingy this weekend :)
ENVA ILS RWY 27 CAVOK, no wind  (set manually) Weight is 30k lbs 

One thing; it was OK until I flew the GS 160kts Flaps 30, as soon as I slowed down to Vref+5 (around 125kts) and added the 45 flaps the oscillation began.

@Pils

Edited by sztrova
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6 hours ago, marcvc said:

I did my first flight with 1.5.2 and observed the same thing.

ILS30 into ESSB
After GS capture autopilot continuously oscillates between 0.55 and 0.65 AOA.
Disconnecting AP immediately stabilises the descent.

ESSB METAR ESSB 031520Z 24008KT CAVOK 07/M08 Q1003

Never observed this before.

Same thing for me with my first flight on the newest patch. Was on ils10 into RCSS it had pitch oscillations until I disconnected the auto pilot. 

Metar was 031900 and wind was 090/11

Edited by sunake
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Just had the same oscillations ILS approach for landing at EGKK (Gatwick) QNH1010 winds 270/10 rw 26L approach speed 125Kts, version 1.5.2. Never had on any previous flights with older versions (first full flight with this version). No problems with climb.

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I also experienced these oscillations only on approach. I was doing the ILS 17R into KSDF. I intercepted the localizer on vectors at about 8DME and the aircraft auto-transferred to green needles correctly and captured the glideslope. The aircraft appeared to be completely centered on the glideslope while descending but the flight director would continuously oscillate. I disconnected the autopilot and noticed the flight director behavior continued. While the autopilot was turned off, I turned off and then re-enabled the flight director, re-armed APPR, and then the autopilot, but the behavior continued. Winds were around 210 degrees at 14kts. Had 12 passengers and about 3000lbs of fuel left on approach. 

Edited by boctal
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  • 4 weeks later...
On 4/6/2022 at 8:03 AM, oisin650 said:

Hi all, changes have been made to the beta build to eliminate this behaviour. This will be included in the next release. 

Wanting to update to the current version as of 5/2/22. Could anyone comment on whether this behavior has been corrected in the  current download version?

Thanks

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15 minutes ago, imn2sims said:

Wanting to update to the current version as of 5/2/22. Could anyone comment on whether this behavior has been corrected in the  current download version?

Thanks

No, not yet changed since 4/1/22.

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  • ois650 changed the title to Glideslope oscillations
  • 2 weeks later...

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