Thanks for all the replies and discussions. Very useful!

dry V1 and wet V1
 

bottom pag 190

Differences between dry V1 and wet V1?

Can someone explain (if possible!) a possible scenario when/how V1 can be lower than VMCG? thanks

NEVER..V1 has ALWAYS to be higher than vmcg.

It's a regulation requirment that states that:

V1 must be equal to or greater than Vmcg
VR must be equal to or greater than 1.05 Vmca
V2 must be equal to or greater than 1.10 Vmca

If you want you may check this discussion about V1 and VMCG.
http://www.pprune.org/tech-log/30174...elow-vmcg.html

Imagine to have an engine failure after V1 and you have to continue the takeoff run. If your VMCG at this stage is higher of V1 you would not be able to keep the aircraft on the centreline with the remaing engine on T/O power! (without exceeding 30feet of desplacement and without using the steering wheel) So that's the reason we must have VMCG always lower or equal to V1!

Hope it helped! :ok:

Thanks Bio
that is exactly the answer I was expecting, and apparently we found an other 'Error' to the ACE book!
So be careful at pag 190, last question!

No problems! :ok:

In my personal opinion, that book is a great way to revise fastly the ATPL subjects but has to be read with attention. If somebody wants to study or to learn something new it's better if he gets some other proper publications..or he could even read pprune!

I'm amazed by the knowledge of this forum!!! :cool:

jimmygill wrote:

Uh-oh! Then what have I been selecting in the 737 when I select a derate of 24k or 22k? And I'm not an engineer/mechanic - I hope I'm not in trouble!

;)

I'm open to corrections, but derates and assumed temps can be used combined or separately. The max assumed temp is 75% of the rated thrust. If you only need 60% of 27k, you can derate to 24k and assume 85%. (Or something along those lines.)

All selectable from the safety and comfort of the cockpit. No plug changing required.

Fixed Derates are done by the OEM usually to leave room for further expansion and development on an engine/airframe platform...Pilot selected Derates are what, that word usually implies in non-engineering parlance:8


btw what's wrong with HTBJ--all you really need to know...I think at times all ATP topic get a little 'creative with aerodynamics, and actually end up missing the important facts....If an interviewer wants to hear crap spouted from that book at him---then read, the book and to get the stinking job, as times are lean and everything is a hustle:}... thereafter, use the leaves therefrom, for paper airplane construction, as, you'll learn far more aerodynamic theory in that way:rolleyes: