Green Dot Speed
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Green Dot Speed
I recently come across the phase "green dot speed" I understand that it is the lowest L/D ratio for the given weight and condition of flight ? correct ?
when is it normally used ? Is it similar to Boeing flap up speed or v2 +100 ?
Also came across the Airbus perf charts ? what is T ref , T max, Grad 1 and Grad 2 ? How do u use the figures ?
when is it normally used ? Is it similar to Boeing flap up speed or v2 +100 ?
Also came across the Airbus perf charts ? what is T ref , T max, Grad 1 and Grad 2 ? How do u use the figures ?
Join Date: Jul 2001
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According to the FCOM:
In approach mode, with speed managed and the aircraft clean, this is the target speed. It is also the target holding speed. In reality, if minimum clean speed is required, a speed a few knots above green dot is selected (i.e. speed is no longer managed).
Green dot speed.
Engine out operating speed in clean configuration.
(Best lift to drag ratio speed).
Corresponds also to the final takeoff speed.
Represented by a green dot on the PFD scale. Below 20000 feet equal to 2 × weight (tonnes) + 85
Above 20000 feet add 1 knot per 1000 feet
Engine out operating speed in clean configuration.
(Best lift to drag ratio speed).
Corresponds also to the final takeoff speed.
Represented by a green dot on the PFD scale. Below 20000 feet equal to 2 × weight (tonnes) + 85
Above 20000 feet add 1 knot per 1000 feet
when is it normally used ?
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Green Dot is minimum speed. Comparison in the Boeing world would be Vref 30+80 when clean, Vref 30+60 at flap 1, etc.
Tref, Tmax, and the Grads are performance terms. I may still have an Airbus performance document around if you are interested but Airbus performance is best left to a laptop...
Tref, Tmax, and the Grads are performance terms. I may still have an Airbus performance document around if you are interested but Airbus performance is best left to a laptop...
