I have been calculating this question but I just don't seem to get the correct answer.

For this question use Performance Manual CAP 698 SEP1 Figure 2.3.

Using the climb performance chart, for the single-engine aeroplane, determine the ground distance to reach a height of 2000 ft in the following conditions:

Given:

OAT at take-off: 25°C

Airport pressure altitude: 1000 ft

Aeroplane mass: 3600 lb

Speed: 100 KIAS

Wind component: 15 kt Headwind

My Workings

*TAS = 104kt (from using CRP-5)

GS = 104kts - 15kts = 89kts* Climb Gradient = 10.7% (from chart)

Still Air Distance = (2000 / 10.7) X 100 = 18,691ft

Ground Distance = 18691 X (89/104) = 15,995ft

But the CAE Oxford ATPL says that 16,850ft is the answer.

The next closest answer is 15,750ft which is what I would choose.

Please help me out here, thank you in advance!

Reference: CAE Oxford ATPL Chapter 8, Question 4.