• Posts: 66

jukzizy created the topic: Cpl Navigation

Refer to the sydney wac in vfr day work booklet.

The following details pertain to a direct flight from bathurst(YBTH)(3325S 14939E) to DUBBO (YSDU) (3213S 14834E)
You depart YBTH at 2305 UTC and at 2317 UTC u obtain a pinpoint over hill end town ship(aproximately 25 nm from YBTH)

Using this data the estimate for YSDU is closest to:
A) 2400 UTC
2342 UTC
C) 2348 UTC
D) 2355 UTC

• Posts: 5

Qfly replied the topic: Cpl Navigation

WE tend to over-think these problems, keep them simple and follow the basic rules of nav, first of all measure how far you have to go from Hill End to Dubbo? It is 64nms from Hill End to Dubbo.

Next work out how fast you are travelling? Measure your distance from Bathurst to Hill End, this is 25nms.

You already know the time it took from Bathurst to Hill End, simple as:

2317
̶̶ 2305
0012 minutes

You covered 25 nms in 12 minutes, use the simple formula to work out speed:

Speed = (distance divided by time by 60). Looks like this: Speed = D ÷ T x 60

In this case: 25nms ÷ 12 x 60 = 124.9 (let’s call it 125kts)

Now you have your speed, simply see how far you have to go? It is 64nms from Hill End to Dubbo.

So now use the formula to work out time: Time = distance ÷ speed by 60, looks like this: Time = D ÷ S x 60.

Put in the numbers: 64nms ÷ 125kts x 60 = 30.71 (round up to 31minutes)

So now we have our numbers, just add 31 mins to (2317) and you get 2348.

Hope this helps, even if a little long winded