Bug Report: Critical Bugs in Time Skip, Stepclimb Logic, Speed Holding and Top of Descent Calculation

  • Dear IPACS Development Team,

    First of all, thank you for the continued work on Aerofly FS 4. The simulator’s performance, stability, and visual quality remain outstanding, and it is clear that a great deal of care and effort goes into each update.

    After extensive testing of the latest version, I would like to report several important issues that appear consistently across multiple aircraft and flight profiles. These are not feature requests, but reproducible behaviors that significantly affect medium- and long-haul operations.

    1. Stepclimb behavior when skipping forward in time

    On long-haul flights, stepclimbs currently cannot be executed correctly when using the time skip function.

    • If the flight is initialized at FL310 with a final cruise altitude of FL350 entered in the FMC/MCDU, skipping forward in time causes the aircraft to jump directly to FL350, ignoring the active MCP altitude.
    • If instead the cruise altitude is set to FL310 and stepclimbs are performed manually, the opposite occurs: after stepclimbing to FL330 and reaching the altitude, skipping forward in time causes the aircraft to descend back to the initial cruise altitude (FL310).

    This behavior is consistent across all tested aircraft. In short, it is currently impossible to perform proper stepclimbs when using time skipping, as the aircraft will either climb prematurely to the final cruise level or descend back to the initial one, depending on the setup.

    2. Autopilot and autothrottle speed control after time skip

    When skipping forward in time on any flight, with any aircraft, the autopilot or autothrottle consistently fails to maintain the commanded speed.

    After approximately 15–20 test flights, the result is always the same: the aircraft speed drops about 15–20 knots below the set value. Reestablishing the correct speed takes a considerable amount of time, and if time skipping is used again (which is common on medium- and long-haul flights), the issue reoccurs immediately.

    This happens regardless of aircraft type and whether the speed is managed via FMC/MCDU or manually selected.

    3. Top of Descent placement

    Across all tested aircraft, the calculated Top of Descent consistently appears to be 10–15 NM too late to allow a smooth, continuous descent.

    This was tested at multiple airports and regions (RJTT, EDDF, KJFK, WIII, VHHH, among others), with different STARs and approaches. In every case, an earlier TOD by roughly 10–15 NM would result in a far more realistic continuous descent that better follows the programmed vertical profile.

    These issues have a direct impact on realistic flight operations, particularly in the medium- and long-haul environment, and resolving them would greatly improve the overall simulation experience.

    Thank you very much in advance for taking the time to review these points and for any future implementation of fixes. Aerofly FS continues to be a remarkable simulator with excellent performance and visuals, and I am confident that, with these mentioned bugs fixed, it will only keep improving.

    Kind Regards,

    AeRodri

    Specs: 16-inch MacBook Pro 2019, 2.3 GHz 8-Core Intel Core i9 Processor, 16 GB 2667 MHz DDR4 RAM,
    AMD Radeon Pro 5500M 4 GB, 1TB Apple SSD, currently on MacOS Sequoia 15.7.3 + 2x Alienware AW3225DM.
    On the latest version of AeroFly FS 4 from Steam. Visit my dedicated AeroFly Instagram: https://www.instagram.com/realflightops/
    Visit my newly created AeroFly YouTube channel: https://www.youtube.com/@RealFlightOps

  • Dear IPACS Team,

    Sadly I saw no reaction on this extended bug report since I posted it about two weeks ago.
    I would greatly appreciate if you could kindly review the serious bugs detailed in my post, as they significantly impact medium- and long-haul flights and need attention for the next update.

    Thank you in advance.

    Kind Regards,

    AeRodri

    Specs: 16-inch MacBook Pro 2019, 2.3 GHz 8-Core Intel Core i9 Processor, 16 GB 2667 MHz DDR4 RAM,
    AMD Radeon Pro 5500M 4 GB, 1TB Apple SSD, currently on MacOS Sequoia 15.7.3 + 2x Alienware AW3225DM.
    On the latest version of AeroFly FS 4 from Steam. Visit my dedicated AeroFly Instagram: https://www.instagram.com/realflightops/
    Visit my newly created AeroFly YouTube channel: https://www.youtube.com/@RealFlightOps

  • Thank you for your report, these are known issues. For the time skip the sim doesn't care about what you've set in the aircraft, it cares about the navigation route set in the menu, i.e. the cruise altitude set in the navigation menu.

    None of them are "critical bugs" though, we consider a bug as critical when it crashes the app or makes the app unusable.

    Regards,

    Jan