B737 Series Flap/Speed selection policy different to FCTM procedure
Re flap/speed selection for the B737 Series. Boeing FCTM discusses extension and retraction of flap policy. Assume you are flying at current airspeed 210 knots clean with AP and AT engaged. Time has come to configure for landing..
FCTM states depending on weight, select flap 1 and immediately wind MCP speed back to 190 knots. Approaching 190 knots select flap 5 and wind MCP speed back to 170 knots which depending on weight is manoeuvring speed for flap 5. Then gear down and select Flap 15 and wind MCP back to 150 knots. Finally, select flap 30/40 and wind back MCP to Vref + 5.+ additives as appropriate. Similar process for the 737NG I presume?
One particular Asian operator has introduced a different procedure for the Classic and the 737-800 and 900. In each case, when selecting flap in stages as described above, their SOP is not to select the manoeuvring airspeed for the new flap setting until the flaps reach the new setting. For example if the aircraft is at Flap 15 and 150 knots and landing flap is called for, the PM selects 30 or 40 and waits until the flaps have stopped moving. Once the flaps have stopped at the required setting the SOP is to then adjust the MCP speed at pilots leisure to VEF 30 or 40 plus additives.
Their rationale is that if an asymmetric flap occurs during extension, it is best to have the higher speed for controllability reasons rather than the lower speed for the planned for final setting.
Apologies for the rather convoluted explanation, but is this an approved Boeing procedure (i.e. don't set the final MCP speed until the flaps have stopped operating)? Or is it a company initiated procedure, rightly or wrongly, designed to pre-empt a potential flap non-normal? How valid is that company procedure and is it widely used by other Boeing 737 operators even though not mentioned in the FCTM?