Using the "Navigation Workbook" [edition last revised 2021 but says 2020 in the margins] (and having looked at the published Errata)… can anyone please help me and explain:

Page 65 question 8 on the Exercise: "Avoiding Controlled Airspace".

In short, the question asks … "When is the earliest you can climb … and REMAIN OUTSIDE controlled airspace" … BUT the answer is ... "If you need to climb and remain INSIDE the CTA" ... (thereby effectively answering a different question???).

Please see screenshots of question / answer and what I think is the right answer to the ORIGINAL question.

Thanks, Tim

Hi t117tim,

You are correct, there is a typo in the answer and it should read “If you need to climb and remain outside controlled airspace”

However, the answer in the book with the exclusion of the typo is correct.

The critical corner is the 4000ft to 8000ft step at 54 miles.

We are only interested in this step and avoiding it, so we need to know how far before 54nm we can climb to 4000ft. The rest doesn’t matter.

Please see the attached worked solution.

Let me know if you have any questions.

Thanks
Harry