CRP 5 correct to 1 kt
Should an instrument be read to a greater accuracy than the smallest
graduation on its scale ?
I reckon, for the pooleys CRP 5, maybe half a graduation is ok, but the ATPL questions take the biscuit.
For example, take the following sample navigation feedback question
(Italian feedback).
14) Given:
True HDG = 233°,
TAS = 480 kt,
Track (T) = 240°,
GS = 523 kt.
Calculate the W/V?
A 110/75kt
B 115/70kt
C 110/80kt
D 105/75kt
They give you TAS 233 Kts and GS 523 !!!
And then they have the cheek to present possible answers within very
close values.
For this question I got out my CRP 5 and a pencil. I sharpened the
pencil lead down so it's diameter was ~ 1 micron.
I proceeded to do the question as accurately as possible under a x50 microscope. I still did not get an answer that matched the possible answers.
Do they expect you to use a laser to etch the wind dot on the Perspex
face of the CRP 5 ?