Also, the indications are that you can expect a 5 to 10 kt reduction in speed during the flare maneuver.
You have to ask why does Boeing recommend (among other things) an additive of half the steady HW component. A reply I had from Boeing over 25 years ago was that it was based on many years of jet transport experience. That is all it said. The FCTM for the 737-300 says "...while the steady HW correction should be bled off approaching touchdown". There is no definition of "approaching touch-down".
I may be wrong, but the clue when to start bleeding off the HW component additive may be found in Volume One Supplementary Procedures Adverse Weather, sub heading Approach and Landing," which discusses ice formation observed on airplane surfaces with the advice to add ten knots to the normal Vref. It goes on to say "this ensures maneuvring capability".
A Note states the "combined airspeed corrections for ice formations, steady wind and gust should not exceed a maximum of 20 knots". We know that, because speeds above Vref +20 risk an over-run on a limiting length runway - hence the GA requirement in terms of stable approach criteria if speed exceeds Vref +20 knots.
But - there is a second Note and that says "To prevent increased landing distance due to high airspeed, bleed off airspeed in excess of VREF +5 knots + gust correction
when below 200 feet AGL. Maintain the gust correction to touchdown". .
This suggests to me that the Boeing term "approaching touchdown" can arguably be defined as below 200 ft - and NOT as some people interpret as during the flare manoeuvre.
The HW additives are to account for the steadily decreasing wind experienced on short final which is due to wind surface friction. The wind at five feet above the ground may be 5 knots and at 25 feet perhaps 8 knots and 50 feet maybe 12 knots and so on, until reaching a steady wind unaffected by surface friction which is known as Free Stream wind and which occurres around 2000 feet AGL.
Over-runs are usually caused by excess speed on final approach up to touch down well down the runway. It is my experience that most pilots are reluctant to deliberately bleed off the HW additive and instead assume the flare will do it for them. Well it doesn't always happen that way.
If Boeing state in the FCTM that 200 feet is their idea of the starting point when to commence a deliberate bleed back of airspeed in excess of VREF + 5knots + gust correction, then how else can the original statement of FCTM General information page 1.14 (in my copy of the B737-300 FCTM) that gives the words "steady HW correction should be bled off
approaching touchdown?" be interpreted. To me it is black and white. At 200 feet you commence speed reduction in order to meet the Boeing advice of "bleeding off the steady HW additive.
Of course the pilot should brief his intention otherwise he can expect screams of "SPEED SPEED SPEED" from a thoroughly alarmed but not very clued up copilot.
