Date: 201711
Local time of day: 0601-1200
Location: ZZZ.Tower, US
Flight conditions: VMC
Light: Daylight
Aircraft: Regional Jet 200 ER/LR (CRJ200)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Time Pressure; Communication Breakdown
Second reporter function: Pilot Flying; Captain
Anomaly: Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Regained Aircraft Control
Contributing factors: Human Factors; Procedure
Primary problem: Procedure

Narrative: On approach; I was the pilot monitoring. ATC cleared us down to 3000 ft; then cleared us for the visual approach. We were backing the visual up with the ILS. Weather was mostly clear; and visibility was good. The captain and I had thoroughly briefed our descent and approach; and all was going according to plan. We were level at 3000 ft; still doing 250 kts on a straight in approach. We were getting close enough to the airport; that I expected the captain to begin slowing to get configured for landing. But he didn't slow down. He mentioned the previous day how he didn't like when pilots slowed too early to configure. He said he'd been flying for almost 40 years; and had 20;000 flight hours. I knew he had to slow to get set up to land. But around 18 miles out; I'd had enough; decided he wasn't planning to slow down soon enough; and stated that we needed to slow down to configure. I suddenly thought we also might be going too fast for the airspace we were in; and stated that to the captain as well. He replied everything was fine; he'd slow down soon and we were in Class B airspace; which sounded wrong to me. I repeated that either way; we have to slow down now or we won't have enough time to properly configure. He agreed; and started to slow the aircraft. Shortly thereafter; we arrived at the FAF; and he started down; still doing approx. 225 kts and not yet configured. I couldn't believe what I was suddenly seeing. This was clearly all wrong; and I stated; 'We need to go around; this looks bad'. The captain replied; 'Give me a second; I can fix this this'. He pulled the nose up a bit to help slow down; then called for flaps 8; 20. I was about to call again for a go around; but the speed was dropping off and I didn't want to risk not getting flaps in asap; in case the captain decided to continue the approach anyway. I wasn't sure how it would go if I attempted to take the controls from him; considering how focused he was on getting us down. So; I reached for the flap lever and deployed flaps 8; and immediately looked up at the airspeed and saw it was 210 kts (10kts fast. I never had a captain call for flaps early before. I always check; but I'm never rushed like this) I waited until 200 kts to deploy flaps 20; and all other flap extensions were done at the proper speed. He called for gear down; and flaps 30; then 45. I did the before landing checklist; and everything was complete. We were stabilized by 500 Ft and landed without further incident.I allowed the 20;000 hour 'senior captain' to cloud my judgment. I didn't expect someone with so much heavy jet experience would ever put an airplane with 53 people on board into such an unstabilized approach. While still 18 miles out; I wanted to give him 'room' to fly the plane the way he wanted (up to a point); and while I did tell him twice we needed to slow down; I never thought it'd get to the stage it did. I was fairly assertive; but in hindsight; should have been much more so. Things happened fast. At the FAF; when things looked all wrong to me; I should have been much more assertive; if not outright forceful in calling for a go-around.  The attitude of the captain; in my opinion; was one of disregard for the rules; he could fix anything; and he knew better than the company about how to do things. I am not trying to 'throw him under the bus'; but I am recounting what I saw and experienced in my time with him.This has been a sobering; eye opening event for me. My desire to maintain a harmonious working relationship with a captain will never again get in the way of me taking action as the professional pilot I am. I will never again defer to anyone regardless of hours or experience if a situation like this occurs again. If it 'looks bad to me'; I will take control early. I have found out the hard way that anyone can take me and my passengers down a dangerous road very quickly. I do my best to follow strict adherence to company policy; standards; and SOP. I will henceforth make sure my captains do the same. The rules and procedures are there for are reason; and need to be followed. They are what keep us alive.


Second narrative: [Report narrative contained no additional information.]


Synopsis: CRJ-200 flight crew reported that they were late configuring the aircraft for landing.