[Andrew Sinclair]

I am a great admirer of John Farley and tend to read his articles first when Flyer hits the door mat. This months article discusses approach speeds and he mentions that the certification requirements specify an approach speed based on on 1.3 times the appropriate stall speed.

I have flown the exercise he advises and also checked my POH/FM several times and I cannot find this relationship in my POH/FM.

As an example my POH/FM figures are as follows:

Approach Speeds IAS (KT)
Clean = 65
Flaps Down = 61

Stall Speeds IAS (KT) for 0° Angle of Bank
Flap 0° = 42 x 1.3 = 55 (i.e. Δ = 10KT)
Flap 10° = 39 x 1.3 = 51 (i.e. Δ = 10KT)
Flap 20° = 38 x 1.3 = 49 (i.e. Δ = 12KT)
Flap 30° = 36 x 1.3 = 47 (i.e. Δ = 14KT)
Flap 40° = 35 x 1.3 = 46 (i.e. Δ = 15KT)

The Δs between the 1.3 x figure and the POH/FM specified technique are quite significant and I wondered if John or anyone cold shed some light of this for me.

I do not fly my approach by the numbers necessarily and this is not a post about the technique one should/should not use but rather I have found on some occasions that the POH/FM doesn't seem to follow the generally agreed views and this is an example of this; the call to "Check you POH/FM" doesn't always help.

In the extreme one could fly an approach at, for example, 61KT IAS and break the nose wheel off and the view maybe "Well the approach and landing was too fast" equally one could fly an approach at say 46KT (i.e. 1.3 x stall speed for configuration x) and come to grief upon the chorus of comment might be "Well he was flying at 15KT below the recommended approach speed so what do you expect".

Lastly this maybe an example of "Andrew, get a life and stop babbling on......" and I am happy to accept that or it maybe something I clearly have some confusion over in which case I would be grateful for any sensible views.