A340
Join Date: Aug 2002
Location: All the leaves are brown, and the sky is grey....
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SPEED (and MACH) is a A/THR function annotated on the FMA, although doesnt come with a * function (unlike ALT* or LOC*, for example, where the * indicates engagement of the capture mode)
It is not specific to the A340 either.
Perhaps you could tell us where you heard or read the term and we could be more specific.
It is not specific to the A340 either.
Perhaps you could tell us where you heard or read the term and we could be more specific.
Join Date: Oct 1999
Location: Up there
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During the climb say, you could have modes of
THR CLB NAV
Now as you approach the altitude in the window the modes will change to
SPD ALT* nav
Which is normally announced as "speed, alt star" now a little later when the altitude is captured the mode will change to
spd ALT nav
So another call "alt" will be made.
Now the only thing I can imagine is either you miss heard the call or which ever airline, has SOPs that state you call the "star" and not the mode associated with it as its not actually there yet i.e. ALT* is really the current V/S locked in.
This is how that 330 crashed I believe.
The A/C was airborne just after takeoff with a massive rate of climb due to the weight of the A/C and two engines at max thrust, it had a low level off altitude in the window.
So the modes changed to SPD ALT* XXX very early again due to the high rate of climb, then they simulated an engine failure which still left the A/C in SPD ALT* XXX now the speed rapidly decayed due to the A/C now single engine and trying to maintain the ALT* i.e. the current V/S based on two engines, the A/C never reached the altitude in the window and crashed.
This description is just from memory so any corrections are more than welcome.
So this may be the reason for the “ * ” call as a crosscheck for a sort of variable mode.
THR CLB NAV
Now as you approach the altitude in the window the modes will change to
SPD ALT* nav
Which is normally announced as "speed, alt star" now a little later when the altitude is captured the mode will change to
spd ALT nav
So another call "alt" will be made.
Now the only thing I can imagine is either you miss heard the call or which ever airline, has SOPs that state you call the "star" and not the mode associated with it as its not actually there yet i.e. ALT* is really the current V/S locked in.
This is how that 330 crashed I believe.
The A/C was airborne just after takeoff with a massive rate of climb due to the weight of the A/C and two engines at max thrust, it had a low level off altitude in the window.
So the modes changed to SPD ALT* XXX very early again due to the high rate of climb, then they simulated an engine failure which still left the A/C in SPD ALT* XXX now the speed rapidly decayed due to the A/C now single engine and trying to maintain the ALT* i.e. the current V/S based on two engines, the A/C never reached the altitude in the window and crashed.
This description is just from memory so any corrections are more than welcome.
So this may be the reason for the “ * ” call as a crosscheck for a sort of variable mode.
