I have been tutoring a student on Aeroplane Performance, and helping with the above questions he was stuck on, but I get a different answer, although my method was only very slightly different. I was wondering how confident you are of the wording of the question and that the answers in the ECQB are as you have shown?

For the first one, 320419, you have assumed that the lower altitude of 4000 feet is an aerodrome and so started the climb at screen height, although as written the question mentions only a climb from 4000 feet to 5500. In CAP698 this graph is in a topic labelled "take off climb", but the graph is actually suitable for any climb at 100 KIAS and that label would not be included in an exam annex, as the graph is only labelled "climb".

In addition you have used the TAS and rate of climb at 4000 feet to calculate the distance covered. While TAS and RoC do not change much over 1500 feet, it is significant in the context of the question with answers around 1500 feet apart. To find the distance covered more accurately some estimate of average rate of climb and TAS should really be used, and difference in gradient is enough to change bring the answer closer to 21000 feet than 19500.

Question 320385 does mention an airfield so the screen height is implied, but is still calculated using the performance data for the bottom of the climb.

Now I have taught General Navigation and Flight Planning far more than Performance, so am using the methods recommended for climb and descent questions in those subjects. It is entirely possible that there are different recommendations for answering Performance questions.

For the first one, 320419, you have assumed that the lower altitude of 4000 feet is an aerodrome and so started the climb at screen height, although as written the question mentions only a climb from 4000 feet to 5500. In CAP698 this graph is in a topic labelled "take off climb", but the graph is actually suitable for any climb at 100 KIAS and that label would not be included in an exam annex, as the graph is only labelled "climb".

In addition you have used the TAS and rate of climb at 4000 feet to calculate the distance covered. While TAS and RoC do not change much over 1500 feet, it is significant in the context of the question with answers around 1500 feet apart. To find the distance covered more accurately some estimate of average rate of climb and TAS should really be used, and difference in gradient is enough to change bring the answer closer to 21000 feet than 19500.

Question 320385 does mention an airfield so the screen height is implied, but is still calculated using the performance data for the bottom of the climb.

Now I have taught General Navigation and Flight Planning far more than Performance, so am using the methods recommended for climb and descent questions in those subjects. It is entirely possible that there are different recommendations for answering Performance questions.

## Comment