Aeronautica (Roblox) - Cannot stay level on cruising with Concorde

The usual game issue of sudden decreasing Vertical Speed while being so close to the cruising altitude: 60,000 fleet! Includes my voice.
The Aérospatiale/BAC Concorde featured is originally owned by gp40railfan, painted with Air France/Pepsi hybrid livery "F-BTSD" by soclassified for this purpose.
Aeronautica is a revival of the original Wingz World V by Nahr Nahrstein. Recorded in the game's version 186 (1.156.3.2).
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