29/08/2026
Using ground speed to fly an accurate approach ✈️
The vast majority of approaches we fly are based on a 3 degree approach angle.
And the most common type of approach we fly, is the ILS.
Pilots are trained to fly ILS approaches manually, whilst in cloud - something that can be challenging and requires practice to get right, particularly when flying
‘raw data’.
“Chasing the needles” is a common mistake I see students make when flying raw data ILS approaches.
The key to a successfully flown approach, is knowing what ground track and rate of descent to set.
If we set the correct track and rate of descent, it reduces the likelihood of the pilot “chasing the needles” and significantly enhances the likelihood of a successfully flown approach.
A simple method of setting an accurate rate of descent, is to halve the first 2 numbers of your ground speed, and use that number as hundreds of feet per minute for your rate of descent.
For example, if your ground speed is 160kts, halve 16 = 8.
Therefore you need to set a rate of decent of 800 feet per minute in order to descend down a 3 degree slope.
140kts = 700 feet per minute
130kts = 650 feet per minute and so on.
The pilot will fly the calculated rate of descent and make small corrections as necessary.
Multiplying your ground speed by 5 also works really well.
It’s simple maths that can make flying a stable approach much simpler.
To maintain the localiser, it’s even simpler - place your track line over the extended centreline and localiser needle won’t deviate.
Do you have any rules of thumb that make your job easier?