Seems like a waste of technology having to ignore the FD...
Here's how my training notes see it..
"The pitch command is an attitude reference until the vertical speed is 600'/min. With the vertical speed between 600 and 1200fpm, the command is a mix of attitude and speed command. For greater than 1200fpm, it is a speed command. This vertical speed requirement gives windshear protection. The takeoff airspeed reference is as follow:
1) The greater of the airspeed at rotation+10kts or V2+10kts. If the airspeed exceeds this value for 5 seconds, the reference becomes the lesser of current airspeed or V2+25kts.
2) If an engine fails, the reference is the airspeed at engine-out with a lower limit of V2 and an upper limit of V2+10.
3) If a higher MCP speed is selected, the reference increases to that speed.
For takeoff with an engine out, the operation is similar, but the attitude/airspeed mix function occurs between 0 and 600fpm."
At 400', if VNAV is armed, we know that current airspeed is used.
Did Boeing decree that the FD could not be used for takeoff... or is this a pilot/airline thing?
Thanks.
NSEU.