Fokker 100 v1.2 – Speed brake lever behaviour
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Hi
I would like to report what I believe may be an issue with the speed brake logic in the Fokker 100 v1.2.
I have the impression that in v1.0, when the speed brakes were extended and engine power was advanced, the speed brakes would automatically retract and the speed brake lever would also return to the IN position.
In v1.2, the speed brakes still retract automatically when engine power is advanced, but the speed brake lever remains in the OUT position.
This creates a problem because when the thrust levers are subsequently brought back to idle, the speed brakes extend again automatically, since the speed brake lever is still in the OUT position.
So, if my understanding of the real aircraft logic is correct, I believe the speed brake lever should also return to IN when the automatic retraction occurs.
Could you please confirm whether this behaviour was intentionally changed in v1.2, or whether it is a bug?
Thank you!
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Hello Ratman, you are correct in the logic during conditions where the speed brake is out and the throttle is advanced beyond the MIN T/O, it should automatically retract the brake. However the only condition this does not work is when the landing gear is down or selected down.
Do you recall if the landing gear was down when the speedbrake did not select in? Do you recall if the throttle advanced high enough past the MIN T/O position?
If landing gear was down and it did not retract the speedbrake this is normal as per the aircraft. If the throttle did not advance far enough it is normal.
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Hi,
Thank you for your reply.
I did some additional testing to try to reproduce the issue under different conditions.
The first test was during descent. I used the speed brakes to help capture the PROF descent path. Once the aircraft captured the profile, the thrust increased as expected, but the speed brake lever did not return to the IN position.
I then tested it in Vertical Speed mode, descending at 500 ft/min and with the aircraft speed significantly above the selected speed. The thrust increased, but again the speed brake lever remained in the OUT position.
I also tested it using the autothrottle manually. I advanced the thrust levers all the way to maximum, and the same thing happened: the speed brakes retracted, but the speed brake lever remained in OUT.
For all of these tests, the landing gear was retracted and the flaps were also retracted.
I also removed all my keyboard/controller bindings for the speed brakes and operated the speed brake lever using the mouse, just to make sure that no control input was causing the behaviour.
I am using MSFS 2020.
I am quite confident that this worked differently in version 1.0, as this was actually something I specifically tested at the time. In v1.0, when the thrust increased and the speed brakes automatically retracted, I remember the speed brake lever also returning to the IN position. In v1.2, the speed brakes retract, but the lever remains in OUT, which means that when the thrust is subsequently reduced back to idle, the speed brakes extend again.
Hopefully these additional tests help identify what is happening.
Best regards,
Flávio -
Hi,
Thank you for your reply.
I did some additional testing to try to reproduce the issue under different conditions.
The first test was during descent. I used the speed brakes to help capture the PROF descent path. Once the aircraft captured the profile, the thrust increased as expected, but the speed brake lever did not return to the IN position.
I then tested it in Vertical Speed mode, descending at 500 ft/min and with the aircraft speed significantly above the selected speed. The thrust increased, but again the speed brake lever remained in the OUT position.
I also tested it using the autothrottle manually. I advanced the thrust levers all the way to maximum, and the same thing happened: the speed brakes retracted, but the speed brake lever remained in OUT.
For all of these tests, the landing gear was retracted and the flaps were also retracted.
I also removed all my keyboard/controller bindings for the speed brakes and operated the speed brake lever using the mouse, just to make sure that no control input was causing the behaviour.
I am using MSFS 2020.
I am quite confident that this worked differently in version 1.0, as this was actually something I specifically tested at the time. In v1.0, when the thrust increased and the speed brakes automatically retracted, I remember the speed brake lever also returning to the IN position. In v1.2, the speed brakes retract, but the lever remains in OUT, which means that when the thrust is subsequently reduced back to idle, the speed brakes extend again.
Hopefully these additional tests help identify what is happening.
Best regards,
Flávio@Ratman in all these cases if the throttle advanced pass the MIN T/O or pass more than the thrust lever angle of the upright position then yes it appears you have found a bug.
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Thank you for the feedback. I've just had a read of the FCOMs, and it does look like the speed brake lever should return to the IN position during automatic retraction. I have logged this on our internal tracker for our development team to look into further.
Mark - Just Flight
