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## CPL Nav CTA question

• Posts: 11

### swav created the topic: CPL Nav CTA question

Hi All

I have two questions, it may look very easy but I just want to make sure I have good understanding of it. It is about Controlled Area CTA.

On VTC charts, let say Sydney VTC on the Sydney International Airport the CTA where says C (class Charlie) 2500/SFC it means the area it controlled up to 2500ft? And we can’t go above 2500ft without clearance?
On the next step says C LL1000 - does it mean we can’t go above 1000ft? or we can’t be below 1000ft?
Some questions on practice exams are asking to calculate ROC/ROD to be below and some above. I’m just not sure if let say I want to stay in class C I should be above the LL or below.

It is just very confusing for me and if you could help would be great.

And one more question, in some cyber exam question - like the one below:

Refer Figure 28
figure28.jpg

The CTA steps are centred on aerodrome A. The aircraft is at position X - 5000 ft AMSL. Climbing GS 75 kt.

If controlled airspace protection is desired (ie. remain at least 500 ft above the LL), the minimum rate of climb required, for a continuous climb on track from X, is closest to -

it says “the CTA steps are centred on aerodrome A” - what it means that steps are centred on aerodrome?

Thanks a lot for your help.
Regards
Swav

• Posts: 1962

### bobtait replied the topic: CPL Nav CTA question

Hi Swav

If the lower limit of CTA is 4000 feet it is accepted practice to consider that flight at 4000 feet is outside controlled airspace. I know that confuses some people. Maybe they should have called it the upper limit of uncontrolled airspace!! [ha ha]. So if you fly at 4000 feet beneath the 4000 foot step, you are considered to be outside controlled airspace. if you fly at 1000 feet beneath the 1000 foot step, you are considered to be outside controlled airspace. You cannot count on the protection of CTA unless you are at least 500 feet above the lower limit.

The controlled airspace steps are based on the arc of a circle centered at the aerodrome with a radius equal to the published distance i.e. 20 nm, 30 nm 50 nm etc. in the diagram above, you could tell which limit applied by checking your DME or GPS distance. If you don't have DME or GPS, you could fix your position by reference to map. If you are between 20 and 30 nm, the lower limit of CTA is 4000 feet. If you are between 30 and 50 nm, the lower limit of CTA is 6000 feet, beyond 50 nm, the lower limit is 8000 feet.

• Posts: 11

Thank you Bob.

• Posts: 11

### swav replied the topic: CPL Nav CTA question

Hi Bob
I passed CPL Nav today got 83%. Thank you for all your help.
I will probably come back with some questions from Ops performance and planning as this is my next subject.
Regards
Swav

• Posts: 1962

### bobtait replied the topic: CPL Nav CTA question

Congratulations Swav. That's great news! And a very good mark especially for home study. Well done.

• Posts: 11

Thank you Bob

• Posts: 14

### mayanksingh78@gmail.com replied the topic: CPL Nav CTA question

Hi Bob/ Richard,
Just read in one of the forums that to remain in CTA (steps) you need to be 500 feet above the step height to have positive control???
can you please explain what that means? and where to find the reference in AIP maybe??
thanks
Regards

• Posts: 1962

### bobtait replied the topic: CPL Nav CTA question

Try AIP ENR 1.1 para 3.12