Possible Disagreement w/ Ace Pilot Tech
 

Hello,
I've been reading some excerpts from "Ace: The Pilot Tech Interview." In some of the questions, the author states that a larger jet will have to descend further or will need a faster rate of descent than a smaller plane. The reason given by the author is that the larger plane will have a larger momentum. However, I see that the rate of sink for any given airplane is: ROD = 33000 * deficient Thrust / Weight. If this is the case, wouldn't a smaller plane require a larger descent rate since, its weight would be less? Or is the thrust to weight ratio a lot larger for a larger airplane? Regardless, I do not see momentum playing any role in this. What are your thoughts? :confused:

Ace the technical interview is riddled with inaccuracies (this has been covered here before.), but indeed this is one of the bigger howlers contained there-in.

Put simply,"It's not size that matters"!!. The number of track miles required for descent rely on the aircrafts Lift/Drag ratio and residual thrust/weight ratio, both of which are independent of size.

ATAPTQ is a good source of interview questions, but treat most of the answers given with healthy skepticism.

it does require more distance!!!
 

and i think the difference is the limited speed available during normal descents.

i am on another thread addressing the same subject-primarily asking for the location of an older thread that dealt with the same subject.

i know from experience, B737's, that when it is heavy, i need to start down farther away from the landing airport than when we are empty. we descend at roughly the same airspeeds, in any case limited by the barber pole, and the distance when heavy is more than when empty and light.

i agree "ace the technical pilot interview" deals with the subject poorly in such a way that it is not convincing at all. but it is true in fact.

in real life we never fly the optimum L/D ratio, nor the optimum angle of attack-which if we could, the distance glide ratio should be the same for heavy or light, but the resulting airspeed for the heavy would be greater and the rate of descent would also be greater-but all books i have read say that the distance/ratio should be the same.

Agreed, ATPTI ihas some real howlers in it, lots of them. The bloke who wrote it SHOULD be cringing and hiding in a hole.

hiding in a hole!?
 

perhaps counting his money and laughing.

Read the section on Dutch Roll and how he explains it as the up going wing stalling causing it to fall back down :}

What a lemon!

liters to gallons as well
 

i just saw his conversions from liters to gallons-US and IMP.

perfectly backwards.

21 pounds sterling for something that must not have been proofread at all!

hell, i could write a book like that myself.