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Possible error? E-Text Review Quesions 3.2 Q9
Aaron B
Topic Author
Aaron B created the topic: Possible error? E-Text Review Quesions 3.2 Q9
G'day all,
I'm working my way through the text book and got to Q9 Revision set 3.2) in the E-Textbook.
The reference in the AIP (AIP ENR 1.1 8.8.2.12 (c)) states that:
"For aerodromes without an instrument approach procedure, the alternate minima is the lowest safe altitude for the final route segment plus 500ft AND a visbility of 8KM"
Now this is where I'm confused, I read the answer in the book and it said that either the cloud OR the visibility (one or the other) would warrant an alternate, but the AIP says cloud base and visibility?
John.Heddles replied the topic: Possible error? E-Text Review Quesions 3.2 Q9
It's just a point of grammar allied with each set of words coming from opposite directions, as it were.
The AIP reference "and" requires both items or conditions to be present or exist. The requirement, if met, permits the operation without an alternate.
Ergo, if either one OR the other is not there, then both are NOT present or existing so the AIP requirement is NOT met. The answer indicates that, if either requirement is NOT met, then the alternate is warranted (ie required).
Engineering specialist in aircraft performance and weight control.
bobtait replied the topic: Possible error? E-Text Review Quesions 3.2 Q9
This is a common source of confusion and it is indeed all about grammar. When you are considering whether or not you need an alternate you must ask yourself two questions.
First question. What must be considered when making the decision (the alternate minima)?
Answer. You must consider both the cloud AND visibility.
Second question. Which of these would impose the alternate requirement?
Answer. Cloud OR visibility.
So it depends on the wording of the question. If the question is asking for the alternate minima (that's plural) then the answer is cloud AND visibility. However, if the question is asking under what circumstances would the alternate requirement be imposed then the answer is cloud OR visibility.
