ENR 1.7

Question 1

What is the recommended and maximum tolerance for an altimeter with accurate QNH for IFR?

Answer 1

60ft tolerance with 75ft being immediately unserviceable. Flight is permitted if between these values only to the first point of landing to allow a re-check.

Question 2

What is the maximum tolerance for an altimeter with accurate QNH for VFR?

Answer 2

100ft.

IFR tolerance of 60ft is required for operations above FL200.

Question 3

What must the altimeter be set to below transition altitude?

Answer 3

QNH from a source within 100NM otherwise area QNH.

Question 4

What is the rate of increase of the transition level (above FL110) for decreases in area QNH?

Answer 4

+500ft for every 17HPa below 1013.

1013 = FL110
997 = FL115
980 = FL120
963 = FL125

Question 5

Is cruising within the transition layer permitted?

Answer 5

No.

Question 6

How long is area QNH valid for?

Answer 6

3hrs.

Question 7

What is the maximum difference between an area QNH and an accurate QNH?

Answer 7

5HPa (150ft).

Question 8

Above what height must VFR cruising levels be used?

Answer 8

3000ft.

Question 9

What are the IFR cruising levels?

Answer 9

East = Odd thousand feet.
West = Even thousand feet.