I'm not sure why I got this question wrong??

You are establishing a lowest safe altitude tolerance area prior to take-off for a flight from Alpha to Bravo. The route does not appear on the ERC. Alpha has an NDB, but Bravo has no navigation aid. If the distance from Alpha to Bravo is 60 nm, the tolerance area must include a semicircle centred on Bravo.

The radius of this semicircle would be closest to -


Choose one answer.

a) 20 percent of the distance plus 5 nm

b) 50 nm

c) 10.3 nm

d) 15.3 nm


Answer description:
.
The splay for departure from an aerodrome with an aid is 10.3° The distance Alpha to Bravo is 60nm.

Using the 1 in 60 rule, r = 10.3nm. The semicircle centred on Bravo has a radius of 10.3nm. The question didn't ask you to add the 5nm buffer.

AIP GEN 3.3 para 4.8

Incorrect

Marks for this submission: 0/1.

I chose "c" as 10.3 as it asked the radius of the circle and nothing of the buffer (as it states in the answer). However it gives "d" as the correct answer despite the reasoning in the answer description. Am I missing/confusing something here?

Any help would be appreciated (I copied and pasted the question, unfortunately the diagram didn't copy over but the question is still valid)

I have attached a picture of the question, scroll/zoom to the right to see it - I can't remember how to crop a picture and it's come up like that due to dual monitors.

Cheers
Andrew

The question asks for the semicircle that includes the tolerance area. The extra five miles is part of the tolerance area so you would have to consider the extra five miles even though it wasn't specifically mentioned in the question, because the phrase 'tolerance area' includes the five mile buffer.

Bob

Thanks Bob,

It's annoying how you can know the information, but it comes down to interpretation of the question.

I'll let you know how I go (I have IREX tomorrow morning).

Cheers
Andrew

I passed today with 95%.

Funnily enough this was higher than any of the practice exams I did. Took my time and read each question at least twice.

Thanks Bob, your IREX book has enabled me to pass using home study only - and in my own time.

Cheers
Andrew

WOW Andrew, that's a fantastic score! I'm impressed that you did that well with home study. It's not often that students who do full-time courses do as well as that. All the best with your flying now - I'm sure you'll enjoy it.............

Bob