Ace The Technical Pilot Interview

[captainpierre]

Hi everyone,
I am preparing for the Emirates interview and I am reviewing a bunch of technical stuff. Someone told me to get the "Ace The Technical Pilot Interview" book by Gary Bristow.
On the first page it states: "For an aircraft to climb, lift must exceed the weight of the aircraft."
I always thought that an aircraft will climb because of excess thrust, and lift and weight are almost the same in cruise and in climb (providing your angle of climb is fairly small).Lift will exceed weight only when you rotate into the climb path.
This is very basic so I hope everyone agree with me but I have found similar aberrations on line and in some publications.
Anybody out there ends up arguing about basic stuff or is it just me?
Also, any feed back about that book? Should I trow it away?

[Dream Land]

No expert here, I thought (on an airplane) that to increase speed, thrust must exceed drag. On the space shuttle thrust must exceed gravity, but on an aircraft it makes sense that lift must exceed the weight to fly. :confused:

[Wizofoz]

captain,

ATTPQ has been discussed here several times as it contains glaring inaccuracies all over the place. Wait till you get to his explanation as to why best glide speed increases with weight!!

It's useful as a source of possible questions for the exam, but reasearch your own answers.

And yes, in a climb, the aircraft is in equilibrium as it is not accelerating in any direction. Load Factor (L)= l/w, so if lift was more than weight, the aircraft would be experiencing more than 1g, which is not the case.

[missingblade]

Its a great book for learning how NOT to answer your questions. Many many mistakes. Nice challenge to try and find them all.:}

[Blip]

If you are climbing with the attitude higher than during straight and level flight, would there not be a greater vertical component to the engine thrust? If so that would contribute to the forces opposing gravity. Therefore the wings would be producing LESS lift, not more!

Taking it to the extreme example, how much lift is the wing producing when in a steady vertical climb? I would suggest something close to zero.

[AAIGUY]

If you are studying for an EK interview you are wasting your time.

There is no need for ANY (above the basic) tech knowledge.

examples of tech questions for EK -

1)Is VMCG higher than VR or Lower than VR?
(2)if you heard "whoop whoop Pull Up " on the the approach what would you do? Go around, Land , or talk about it?

Its a 30 question multiple choice done on the computer. The answers are OBVIOUS. No one is asking you to explain the RB211 or anything.

[captainpierre]

http://www.pprune.org/forums/images/smilies2/eusa_naughty.gif No, there is quite a bit of misconceptions about that out there. But in a climb, the aircraft is in an equilibrium, however because of the upward flight path a component of weight is added to the total drag of the aircraft and must be compensated for by adding some thrust if you want to maintain the same airspeed. lift will be higher than weight only when you rotate in the climb. In short if lift is higher than weight all the time you'll be doing a loop.
hope this helps.

[captainpierre]

Thanks, you're right I pick up several other nonsense in that book. I wonder if anybody flunked an interview because of it. I might toss ithttp://www.pprune.org/forums/images/smilies/pukey.gif. Happy Landings.

[Pugilistic Animus]

Boy oh boy! would I love to be in charge of writing interview questions:E---I'd really show that I don't care:*

[Bora Bora]

Well, I'm just glad to know that I am not the only one who thought the book was crap, owing to its many mistakes. Thing is, many of my friends didn't even realize it was full (and I mean full) of mistakes.

Thanks for clearing that up!

[Buttie Box]

Echoing the above, it's rather a guide to interview questions than a serious aerodynamic work. The errors are obvious; for example,

Lift=1/2 x density x V*2 x S x Cl

...he uses the sum instead of the product. :O

Air over the top surface of a wing moves inboard, not outboard, therefore the diagram and explanation of wing tip stall on a swept wing are wrong at best and misleading if you're using this book as a training aid.

However, the questions themselves are useful and if you can answer them and at the same time understand and correct them then you've achieved the objective, albeit paying for the privilege.

The intro states the usual disclaimer and how this is what he researched in seeking a job as a professional pilot. Gary, if you're out there, did you get the job?

BB

[Wing Flex]

Guys & Gals,

This has come up before in the past. The following link describes some errors in the book.

http://www.pprune.org/forums/showthread.php?t=150725

[blueplume]

As Buttie Box said, the most obvious error is the lift equation given as a series of additions rather than multiplication.

Bora Bora made a good point too, namely that many people don't see the mistakes. That worries me a great deal because it means they are learning by rote and regurgitating rubbish and I might end up flying with these muppets (do already in some cases but that's another story...). Interview boards are aware of this!

So if anyone is thinking about it, DON'T BUY IT! There are many, far better publications available. Have a nice meal instead.

[Cim Jartner]

I agree about the book containing innacuracies and the questions are more worthwhile than the answers given.

It took me ages to work through his explaination of why swept tips stall first however, although

Air over the top surface of a wing moves inboard, not outboard, therefore the diagram and explanation of wing tip stall on a swept wing are wrong at best and misleading if you're using this book as a training aid.


is there not some basis in fact in his explaination in as much as the chord line is at an angle to Relative Airflow therefore the sweep does contribute to opposing the inboard flow of air on the top surface of a wing???

I still don't now what wing 'chamber' is that he keeps going on about!!!!

[Mike Strutter]

Aw come on dont trash it.

Yes the book is full of mistakes or over simplified answers. At a pilot level this is not as big an issue as it would be at an engineering or test flight level.

BUT it does get one thinking. And i can attest that i have been asked questions straight out of it at interview on a number of occasions.

Think about it , the pilot asked by their company to attend an interview board of some candidates typically doesnt know the answers (correct ones anyway) to these questions themselves. They then pluck a few questions and answers out of this book for the interview.

Remember; most of the chaff about aerodynamics , flight mechanics etc that pilots are taught for examination is over simplified .Im not saying we are stupid or lazy, more that we are generally sold the easy answer because we have so much else to learn at the time (met, law...). Back in the days, i had three years of maths and dynamics instruction before we could learn about the above because it was so complex.

Also bear in mind that a lot of the answers out there are only purely theory. The question of how a wing generates lift is still a phenomenon despite what anyone will tell you.

So;as a good book to prepare for Interview i would say most certainly.
As a book that gets the pilot thinking; definately.
And as a textbook in aeronautical engineering i would say skip it.

Mike

[Pugilistic Animus]

To those here who advocate the use of incorrect information in flight theory---it makes absolutely no sense! you NEVER EVER know when you need to rely on the correct answer---that is complacency at its worst!

Forget about stupid interviews do it for yourselves:*

the mountains don't care about interviews!!!

[ClippedCub]

As has been touched on here, the equation is,

(T-D)/W

If Thrust, T, is greater than Drag, D, you climb or accelerate. If (T-D) is greater than W, then you can accelerate going straight up, like some fighters.

This equation is also used to find climb angle, ROC, etc.

[oz in dxb]

I have to agree with Blip.
Your vertical component of lift has to equal the weight of the aircraft in the climb, which means that the actual amount of lift being provided is less than the weight of the aircraft.

In level flight lift is equal to weight. Consider a vertical climb. This shows that lift is not required, but only climbs because of thrust greater than drag.
So the greater the climb angle the less the lift required.

An aircraft climbs because it has excess thrust.

Oz

[oz in dxb]

Captainpierre, if you are STILL wanting to come to EK, provided you have read the ME forums about us, brush up on your CPL theory of flight and meteorology.

It's pretty much basic stuff (that most of us have forgotten!)

Oz

[BOAC]

I've never read the book (and never will!) but having followed the 'critique' of it on PP, I have to ask how it ever got into print?

[jetopa]

Hi,

not that I am preparing for any particular interview, but I figured it sure would be nice to have some sort of 'bible' for us pilots where I can look after certain things I haven't bothered to think about for ages...

Who knows which publication would be suitable?

(a little bit afraid that my next supervisor will ask me to determine the convergence of meridians at a given location next time...):ugh:

[flyjet787]

During a climb the aircraft weight is divided into two components.
One is the weight of the aircraft perpendicular to the flight path and the other one is the component along the flight path.

Lift= weight perpendicular to the flight path,

Thrust= drag + weight along the flight path.

Therefore lift is less than weight in a climb.

Life is greater than weight during a turn/bank or when the C.G is forward of its limit in which case lift will have to equal aircraft weight and the elevator download.