Performance-MEP1 takeoff climb data

[stator vane]

in the CAA performance manual for JAR FCL exams CAP 698, Feb 2002 issue;

page 30: there is an example they give to calculate distance from the end of TODR to 1500 ft. and rather than print it all, will hope that some others studying for the UK tests toward the JAR ATPL will have the same manual to open;

"Distance to cloud base= 350/1660 x 90/60 x 1.3 = .42 NM"

i can understand everything on the entire page, except for the
"x1.3"

like wise on page 31, another example; "distance to cloud base=350/1500 x 124/60 x 6080 x 1.3=3811 ft"

i don't understand where the "1.3" is coming from in both cases.

perhaps i cannot see the forest for the trees.

and while we are on the subject, i am finding these charts most difficult. such precision required on such small charts! and their example on page 24 at the bottom, "3370 lb. Using 2000 ft" i can't even get close to that when following them through.

i thought meteo was going to be bad. but i surprized everyone and passed it first time. but this performance really scares me now!!!

[FlyingForFun]

I don't have CAP698 with me at work, so I'm sure someone will correct me if I'm wrong... but I think it's just the safety factor. All gross TODR figures are multiplied by 1.3 to give a net TODR. (And LDR is multiplied by 1.43.)

Although, now I think about it, don't the graphs already include this? Hmm, think I might have to check when I get home!

FFF
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[EGLG777]

Hi Stator

It's the all engines NET gradient safety factor (Which is the gross gradient x0.77).

The Performance exam is not as bad as you may think. I did mine in November and didn't use CAP 698 once. From what I have seen in feedback aswell, the correct answers are quite obvious.

[Keith.Williams.]

Stator,

JAR OPS 1.535 specifies the obstacle clearance requirements for such aircraft. These include, "The assumed gradient from 50 ft screen height to the point of engine failure is equal to the average all engines operating gradient up to the en-route configuration, multiplied by a factor of 0.77"

The engine is asumed to fail at the cloud base, so the gradient below the cloud base must be multiplied by 0.77. This can be done by multiplying the all engines roc by 0.77, or by multiplying the distance to the cloud base by 1/0.77 which is (approximately) 1.3. This is what the author of the CAP 698 has done but he/she has neglected to explain that fact. Unfortunately most of the course notes issued by the FTOs also fail to explain the reason for the (x 1.3) in these calculations.

[stator vane]

thank you all for the quick responses.

i hope it will be easy.

this entire ordeal has been so frustrating.

the note book, from a long distance school, often has mistakes. and when one is in the stages of learning for the first time, or even worse, reviewing after way too long at altitude, it is difficult to discern a mistake on their part- from a misunderstanding on my part- from an oversight on my part-from an assumption on their part-from an ....blah blah blah. then even the CAP doesn't explain each step along the way.

last night after making the post, i checked the oxford's again and i couldn't find the reason they included it.

for some one at my stage, especially in given examples, each little step should be explained clearly at the moment the factor is used in the calculations. at least once!

and it is so frustrating when i come across something like that on a late friday afternoon, especially in the holiday season.

thanks again

[Keith.Williams.]

Stator,

You refer to the OATS manual, so I will do the same. In my copy of their Performance manual, the JAR OPS requirement is quoted at the bottom of page 10 - 5, and the 0.77 factor is used at the bottom of page 10 - 6 to adjust the gradient. This (unfortunately) isn't quite the way it is done in the CAP 698. This problem is not however unique to OATs. I have books from three other schools and none of them explain it properly!

I can understand your frustration, but this is one of the fundamental weaknesses of distance learning. It can only be overcome by contacting your school, preferably by telephone, whenever you have a problem. You can judge the quality of your school on the basis of the way they react to your calls. Most of them will react vey well, but if they don't, or if their explanations don't enable you to understand the subject, you should change schools.

In the case of Performance, you will be having an extremely bad day if your exam contains more than one question requiring the use of the CAP 698 graphs. You will however get questions about why particular graphs have this or other characteristic. Your school should be well aware of these questions and warn you of them during your consolidation course.

Sator,

In my copy of the Oxford Jeppesen manual, the JAR OPS requirement is quoted at the bottom of page 10 - 5, and the 0.77 factor is used at the bottom of page 10 - 6 to adjust the gradient. This (unfortunately) isn't quite the way it is done in the CAP 698. This problem is not however unique to OATs. I have books from three other schools and none of them explain it properly!

I can understand your frustrtaion, but this is one of the fundamental weaknesses of distance learning. It can only be overcome by contacting your school, preferably by telephone, whenever you have a problem. You can judge the quality of your school on the basis of the way they react to your calls.

In the case of Performance, you will be having an extremely bad day if your exam contains more than one question requiring the use of the CAP 698 graphs. You will however get questions about why particular graphs have this or other characteristic. Your school should be well aware of these questions and warn you of them during your consolidation course.