Some B757 Questions?
 

Hello,

First one is about clean speed, I understand it is normally calculated as VRef+80, is this correct in normal operations?

The final question is about assumed take-off thrust temp. I understand that it is dialed in by turning the knob on the TMS before departure? Also is this value depicted as D-TO + ____ °C?

Sorry if these seem like silly questions, but I would appreciate any help given. :)

Kind Regards
BAe 146

>calculated as VRef+80

This is basically correct. To be 100% correct, clean speed is always Vref30 + 80 (Vref for flaps 30, then add 80 knots), regardless of the flap setting to be used for the approach (ie, flaps 20 for a single-engine approach).

>turning the knob on the TMS

While you can use this knob, there are some limits associated with it. AT is normally set using the FMS.

You can only set Assumed Thrust via the FMC on newer FMC's / 757's

Thanks for your help gents, much appreciated! :D

Am I right in saying that the value for a assumed temp thrust take-off on the B757 is depicted as D-TO + ____ °C?

Regards
BAe 146

Correct 146, in nice green letters..

So will Vref30 + 80 be used for the clean speed on departure and also the clean speed on arrival? Or can this differ?

Regards
BAe 146

Yes you have assumed correctly, its all based on a/c weight, basically the Vref30 + 80 speed reduces as weight reduces. Typically Vref30 + 80 varies between 210-195kts at typical landing weights.