Date: 201807
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Night
Aircraft: Medium Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class D ZZZ
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Anomaly: Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented
Contributing factors: Company Policy
Primary problem: Company Policy

Narrative: On arrival at night we were told to slow as much as possible for opposite direction traffic. We were attempting to fly the RNP Z to Runway 23. I was flying about 190 KIAS in a clean configuration. When given clearance for the visual approach we began a descent on the RNP profile. I called for gear down to help us get down on profile; the PM (pilot monitoring) set the condition levers to 1020 as required and the aircraft began a rapid decrease in airspeed. As I attempted to call for flaps 5 as we passed by 180 KIAS we reached about 171 KIAS before power was advanced and the flaps were selected to 5 degrees. I was also is slight descending right hand turn. So we did get below Vmin for flaps 0 by about 9 knots. Airspeed was increased back above 180 KIAS until the flaps reached 5 degrees.I do not agree with our change to selecting flaps as we slow. I do understand this was done to help prevent flap overspeeds and to not use the flaps as a slowing mechanism.  But; what we are setting ourselves up for is more stick shaker events as we head in to winter. If I had the Ref Speed Increase switch on there would have been a good chance of a shaker event if I had loaded the aircraft with a bit more G loading in the turn. Now we set up another set of risks. Do we miss? Do we just as trained add power and continue? Am I still on course? Do I over speed on the recovery? In a jet I can see this working; in the prop world we have 13 feet of propeller drag that is pretty instant on each side of this aircraft. When those props go to 1020 and power is back; we slow very very quickly. My suggestion is we go back to the previous way of putting down the flaps with including the reduction in maximum flap speeds that we used for a couple of years. I do agree putting the gear down first is a good way to slow and should be continued in the profile. Flying by Vmin and putting the flaps down is not a safe way to fly this aircraft. In the summer it is OK but come winter and that Vref increase we will have shaker events. I am sure we have drastically decreased our flap overspeeds but at what cost in overall safety. Remember that the [turboprop] is not in the same environment as the [jet] that pretty much does straight in visual and ILS approaches every leg. The [turboprop] is a complicated aircraft that often flies more intense procedures in a higher risk environment. Safety is number one and this flap procedure should not be continued in this aircraft as we head into winter flying. The reason I am reporting this is I think this is a major safety issue. If I as a 30+ year pilot and former check airman and instructor [am] having problems with this procedure how are our 1000 hour pilots doing with this a busy dynamic environment? I often am calling airspeed flaps as we slow accidentally below 180 KIAS in a clean configuration. I am not looking forward to winter with this procedure. I know the response to me will be that I can select flaps 5 prior to 180 KIAS but pilots due things by repetition and they will continue to use 180 KIAS as the flap selection point in most stressful situations.




Synopsis: Captain of a Part 121 twin turboprop reported getting too slow when transitioning from clean to the first flap setting.