Flightlevel From Canada, joined Jul 2003, 30 posts, RR: 0
Reply 1, posted (12 years 9 months 3 weeks 23 hours ago) and read 7523 times:
Are you talking just about the ASI? If so, the red shows the upper limit of speed, the yellow the lower limit of speed. If the speed gets close to either region, the computers will add or take away thrust and change pitch accordingly. The little green .780 shows the speed that the autothrust is set for. The green dot shows the no flap speed, at this you have to add flap or increase speed. Lastly, the little purple triangle shows the speed that you have selected to fly, and by referencing the diagram, it shows that they were just slightly slow.
Rick767 From United Kingdom, joined Jan 2000, 2662 posts, RR: 50
Reply 3, posted (12 years 9 months 3 weeks 23 hours ago) and read 7521 times:
Just a quick correction to Flightlevel's post, I believe the .780 is the actual current Mach Number, rather than selected. Again not being an Airbus boff I can't say for sure but have jumpseated them enough times to remember that number fluctuates a bit... I'm sure it's the Mach Number indicator.
Also if it were a selected or managed value common sense would suggest it should be in blue or magenta... not green.
I used to love the smell of Jet-A in the morning...
Gate Keeper From Canada, joined Jan 2000, 176 posts, RR: 0
Reply 5, posted (12 years 9 months 3 weeks 21 hours ago) and read 7506 times:
Symbols on Airbus ASI above are:
Red Band is high speed protection region with lower end being Vmo/Mmo.
Green equals sign (left of red band) indicates area where overspeed protection occurs. When it is activated, the pitch trim is frozen. Positive spiral static stability is introduced to 0° bank angle (instead of 33° in normal law), so that with the sidestick released, the aircraft always returns to a bank angle of 0°. The bank angle limit is reduced from 67° to 45°. As the speed increases above VMO/MMO, the sidestick nose-down authority is progressively reduced, and a permanent nose-up order is applied to aid recovery to normal flight conditions. The High Speed Protection is deactivated when the aircraft speed decreases below VMO/MMO, where the usual normal control laws are recovered. The autopilot disconnects when high speed protection goes active.
Magenta triangle indicates managed speed target.
Amber line indicates present speed(also indicated by green mach readout at bottom left) and arrow is speed trend for next 10 secs.
Green Dot (Engine-out operating speed in clean configuration)
This green dot appears when the aircraft is flying in the clean configuration. It shows the speed corresponding to the best lift-to-drag ratio.
Indented amber box on top of black and amber striped tape is called Vls. Vls is the lowest selectable speed that autothrust will allow you to fly.
The top of a black and amber strip along the speed scale indicates the alpha protection speed. It represents the speed corresponding to the angle of attack at which alpha protection becomes active. Alpha protection is not unlike over speed regime where autotrim freezes, pitch attitude is maintained at alpha max and full power (TOGA) is applied.
GE From Singapore, joined Mar 2000, 320 posts, RR: 6
Reply 7, posted (12 years 9 months 3 weeks 10 hours ago) and read 7426 times:
The very botttom of the red bar is Vmax.
That is the lowest of:
-Maximum operating speed if in clean configuration (Vmo/Mmo)
-Maximum gear down speed if gear is down (Vle)
-Maximum flaps extended speed for current flap configuration (Vfe)