JAR PERF EXAM 2nd AUGUST
 

Hi folks,

Can anybody give me a bit of feedback as to how the recent JAR PERF exam was and what type of questions popped up this time?

Also can anyone recommend who offers a realistic databank of past /feedback questions? ( i have bristols already)

Cheers:eek:

Sure
 

This exam had several questions on Vimd with the answer being slightly different in every occasion.

There were NO graph questions at all. As in you didn't have to go over the graph to get an answer.

4-5 questions on why you use Long range speed.

The typical question on why we use cruise climb technique. The answer that time was to get to optimum altitude, etc.


4 or so questions on what happens if you maintain constant speed (Mach, CAS, TAS).

The one I remember is the one I got wrong:
Maintaining constant CAS as you climb, what's going to happen with Angle of Attack and Pitch angle? (Carefull, I could not remember how answer A and B were!)

A) decrease, decrease
B) Increase, decrease
C) remain constant, decreasing
D) remain constant, increasing largely

(The last two answers are apparently wrong)

Why would you NOT fly at optimum atlitude?
A) More tailwind and less headwind at lower altitude (that's what I put down)
B) More headwind than tailwind at lower altitude
C)Because above that altitue temp. remains constant ( or somethng)
D) --------------


I think they also asked about Density Altitude, can't say for sure cause I took both exams on same day.

What speed would you fly in case of driftdown?
A) Speed with max CD/CL
B) Speed for max CL/CD
C) *
d) *

When would Vmcg be lowest? (I think it was more like> WHY is Vmcg something and the answer was, decreased thrust)
(this question is definately in feedback)

What happens with speed Vx and Vy as altitude increases?


About Bristol, I can't complain or know anyone who has complained about Bristol's feedback. They are really good but suffer as much as any other school from incorrect answers in some areas. All in all very good and nice fair amount of money to access their bank.


For Perf, know the many different ways you can define Vimd and what Vimd is for props and Jets.
Also know how many ways they can define MAX lift speed (Vx)


One of the questions I had to use the CAP to make sure and I think it was the only one you could actually verify with the CAP.
It's this one> When can you start a turn after T/O?

I'd be more worried about the HPL exam than the Perf.

Since I'm here I'll throw in the questions I saw on HPL:

When is Critical height reached if you don't use supplemental oxygen and fly in a non pressurized aircraft?

A) 38000 feet
B) 16000
C) 20000
D) 18000
According to my buddie it was 20.000 feet but he wasn't sure about it, I put down 18.000.

When would you have to use 100% oxygen after decompression?
A) 50.000 feet
B) 40.000 feet
C) 20.000
D) 16.000

How can you get hypoxia? (this one was a THINKER question)

i) Blood pooling to extremeties due to G's (think was Gz)
ii) By inability of blood to metabolize oxygen
iii) can't remember this one

The answer was all three.


Sorry but that's all I can remember.

My take on the Perf exam. Don't take my view as gospel as I am not entirely confident about it:

That is a tricky one. The aspect is that you must ignore compressibility to answer it. I think the question specified this...not sure. Without compressibility then EAS and CAS are equal so AoA Decreases and Pitch Decreases with the reduction in thrust. With compressibility, the right answer (IMHO) wasn't present (both increase).

I don't remember that one! I vaguely remeber a question on why the cruise climb cannot be used...basically why use step climbs. Maybe I have lost the plot and confusing the exam with feedback.

I think the question was "Why would you fly 4000' lower than optimum?" Easy as there was only one sensible answer and it was worded as a signification reduction in headwind or a large increase in tailwind.

They did and it was just asking for a definition. Pretty straight forward.

Vmcg is lowest when thrust is least and so a lessened asymmetric thrust effect so it is easier to control with an engine out so the right answer always appears to be when hot'n'high.

Another horrible one as we have to guess if they intend to account for compressibility. My guess is that they do and so both increase to maintain a constant EAS. However, if you look at the Power/TAS chart the TAS also increases BUT my notes say that Vx remains constant and Vy decreases!! Did the question specify TAS? Probably one I got wrong.

This was an horrendous question as I don't recall it actually having the word "driftdown" in the question. I seem to remember the question was what speed for a twin jet, one engine out, in the cruise in a mountainous area, maintaining clearance? The options were CD/CL(MAX), LRC, CD/CL(MIN) and Max lift to drag ratio!! Two right answers for a driftdown. As it didn't actually ever mention a driftdown but S&L (Cruise) I was completely confused. Even CAP698 didn't help. Everybody appealed this.

Actually
 

I'm not 100% sure on what you mean about that question. Do you mean that LRC as well as MAX LIFT TO DRAG RATIO were both the correct answers?

Sorry, not very clear. I mean that "max lift to drag ratio" and CD/CL(min) are the same thing.

I can't explain it but
 

It's definately not a case where both answers are correct. Max lift to drag ratio is the exact answer since it's like this max CL/CD ratio.

The other two with CD/CL max, CD/CL min are incorrect.

If there's a minimum ratio between the two then it's not the one.

If it's max ratio then it still has to have CL before CD

MAX CD/CL ratio and MAX CL/CD ratio are two different things.


I can't explain it on perf level but my teacher gave us a similiar answer option and I didn't like it one bit.

Mathematically CD/CL(min) and CL/CD(max) are the same thing; that is little drag and big lift in both cases. That is why they are the same answer. It has been appealed so hopefully we all get one back.

I still remain uncomfortable with the 'driftdown' bit in general.

:confused: :{