Assumed Temp and Derate Take Off 737NG
 

Hi All 737 NG Drivers
Am a bit confused here. Planned a combination of Assumed Temp and Derate 1 T/O. Noticed the FMC calculated the N1 accordingly but the chevrons indicated Full Thrust of Derate 1 settings. At the Thrust Reduction height, the N1 Annunciated and RCLB annunciated on the TMA. At about 1000 ft AGL I pressed TOGA again and noticed the N1 dropped by about 3%, both Thrust Levers started Retarding and then moved to FULL Thrust.
Qns.... When did the FMC move out of the Assumed Thrust + Derate1 settings.
2. When RCLB annunciated did the FMC move automatically to Full Rate Full Thrust CLB/RCLB power.
3. Why did the N1 drop by 3% on pressing TOGA the second time.
Thanks for any help.

1- at lift off
2- at 15000 ft
the third one it seems to be wrong

Sounds like somebody deleted the climb-1 or climb-2 on the N1 page before T/O.

The chevrons indicate the limit for the selected T/O thrust setting. If derate-1 gives 95.0%, and after assuming your N1 is 92.0%, the chevrons will be at 95.0%.