VNAV issue

[Awemeter]

I've noticed some issues with the VNAV in this aircraft. When flying on a STAR (Standard Terminal Arrival Route) and encountering a manual leg with a disconnect between the approach and the STAR, the plane tends to forget its current situation. It accelerates to over 300 knots and begins to climb and shows that I'm 99 feet below the path on my PFD. It lasts for about 5 to 10 seconds before the aircraft eventually corrects itself, realizing it is arriving rather than departing, and then slows down and stops climbing.

Additionally, I've observed that the aircraft often disregards the set speed in order to get back on the path. For instance, if I'm below 10,000 feet and the managed speed is set to 250 knots, the plane will sometimes accelerate to over 300 knots to get back on the vertical path. I'm not sure if this behavior is realistic, but I thought it was worth mentioning.

[LineDX]

Noticed the same 

[richboy2307]

Hi @Awemeter @LineDX

Can you provide specific route examples of where you've noticed these issues?

Ideally provide the OFP and any F-PLN edits made so we can reproduce the flights and observe the reported issue.

Thanks!

[LineDX]

Hi Vrishabh, thank you for a prompt reply. It happed on YHZ-YUL flight OMBRE2 ARR for ILS 24R approach. It happened on turning from downwind and base leg when IAS automatically jumps to 250kts for a few seconds then gets back to normal. Now everytime I have to ininitate the app mode way earlier to avoid this situation. FYI 

 

Also coming for SLS/LPV app t/d is too late, have to go for a hold to des down. Vdev is close to 5000+ ft. Happed on rnav 23 sls YUL-YHZ with fundy5 are and YUL-Yqm legs where I tried the sls approachs so far. For ILS approaches td is ok. Both the segments planned altitude is FL410 

 

Also noticed the offset does not work on sec flt plan. The option is grayed out when click on anyway. On act flt plan offset works as intended. 

Edited March 6 by LineDX

[Awemeter]

10 hours ago, richboy2307 said:

Hi @Awemeter @LineDX

Can you provide specific route examples of where you've noticed these issues?

Ideally provide the OFP and any F-PLN edits made so we can reproduce the flights and observe the reported issue.

Thanks!

Thanks for the reply. Here is the simbrief flight plan I used. https://dispatch.simbrief.com/options/custom?airline=ETD&fltnum=204&orig=OMAA&dest=VABB&altn=VAPO&date=06 Mar 2025 - 00%3A10&basetype=A35K&ac_order=registration&type=347385_1734345584724&climb=250%2F320%2F85&cruisemode=CI&cruisesub=&descent=85%2F300%2F250&fuelfactor=1&callsign=ETD2GL&reg=A6-XWF&fin=WF&selcal=BQAH&planformat=lido&pounds=0&maps=1&taxiout=20&taxiin=8&flightrules=i&flighttype=s&altncount=1&navlog=1&etops=1&stepclimbs=1&tlr=1&notams=1&firnot=1&stehour=7200&stemin=3000&origrwy=13R&destrwy=09&fl=&pax=AUTO&cargo=&manualpayload=&manualzfw=&contpct=auto&resvrule=auto&taxifuel=0&minfob=0&minfob_units=wgt&minfod=0&minfod_units=wgt&melfuel=0&melfuel_units=wgt&atcfuel=0&atcfuel_units=wgt&wxxfuel=0&wxxfuel_units=wgt&addedfuel_label=apu&addedfuel=30&addedfuel_units=min&tankering=0&tankering_units=wgt&cpt=&fo=&dxname=&manualrmk=&route=KANI3G KANIP N318 GEVED N881 AMBOS M700 PARAR N571 SUGID KETO2B&route_type=&targetfl=36000&targettas=493&disable_tracks=1&force_track=&avoid_airways=&include_fixes=&altnsadv_number=1&altnsadv_radius=438&altnsadv_cig=600&altnsadv_units_vis=m&altnsadv_vis=3000&altnsadv_units_rwy=ft&altnsadv_rwy=7000&altnsadv_exclude=&altnsadv_tsfgfz=1&altn_1_id=VAPO&altn_1_rwy=10&altn_1_fl=&altn_1_route=DOGA2B PPN&altn_2_id=&altn_2_rwy=auto&altn_2_fl=&altn_2_route=&altn_3_id=&altn_3_rwy=auto&altn_3_fl=&altn_3_route=&altn_4_id=&altn_4_rwy=auto&altn_4_fl=&altn_4_route=&toaltn_id=&eualtn_id=&etopsthreshold=60&etopsruleselector=370&etops_exclude=&etopsentry=&etopsexit=&etopsaltn1=&etopsaltn2=&etopsaltn3=&etopsaltn4=&etopsaltn5=&etopsaltn6=&asp4_snapshot=disabled&debug_zerowind=0&static_id=&manual_acdata= and here is the approach I used into VABB. 

Edited March 6 by Awemeter