Date: 202112
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Q400
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
ATC / advisory: TRACON ZZZ
Aircraft component: Trailing Edge Flap
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Time Pressure; Troubleshooting; Situational Awareness; Communication Breakdown; Distraction
Second reporter function: First Officer; Pilot Flying
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Diverted; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Human Factors; Aircraft; Procedure
Primary problem: Aircraft

Narrative: Aircraft X ZZZ to ZZZ1. While on approach into ZZZ1; my FO (First Officer) called for flaps 5 at 180 kt. After selecting flaps 5 degrees; the caution annunciation for FLAPS POWER illuminated. We went missed as published. We ran the checklist for the Flap Power Caution; and we were unable to clear the fault. The flaps were stuck at about 1 degree. We requested priority handling with ATC and asked for initial vectors to ZZZ2. Our alternate was listed as ZZZ3; but after we verified we had sufficient fuel; we decided a ZZZ2 diversion would be operationally more logical as it is a crew and maintenance base.I notified the FAs (Flight Attendant); informed the passengers of the situation; [and] contacted Maintenance and Dispatch. We ran the Abnormal Flap Landing Checklist enroute to ZZZ2 and reviewed the approach for ILS Runway XX. We requested emergency vehicles to standby as a precaution. I took control of the aircraft over from the FO and performed the landing. No other problems occurred after landing and we were able to taxi to the gate normally. After we parked and shut down engines; we met with Maintenance personnel and filled out the maintenance log book. While performing the after-takeoff checklist; I accidentally bumped the #2 power lever forward out of the rating detent into overtravel. I noticed immediately and brought the lever back into the rating detent. It was in over travel for no more than a second or two. I made a separate maintenance entry for that upon landing.Also; while flying to ZZZ2 and the flaps were stuck at 1 degree; our airspeed crept up to around 215 kt. We both had our attention on running checklists and communicating with Dispatch; ATC; the FAs; and we allowed the airspeed to climb past the flap 5 speed limitation; even though the flaps indicated 1 degree. We made an additional write-up for the potential overspeed. I wasn't a fan of Dispatch messaging us information about a plane being available to us in ZZZ2 to resume the trip while we were actively dealing with the [situation]. It added additional external pressure and felt like the gravity of the [situation] wasn't respected.


Second narrative: During approach into ZZZ on Aircraft X; flap power caution illuminated when flaps were selected to 5. We conducted a missed approach and ran the flap power caution checklist. After resetting the circuit breaker; subsequent flap selection still resulted in flap power caution illumination and failure of flaps to move out of zero. We requested priority handling and had ARFF (Airport Rescue Fire Fighting) standing by as a precaution. After successfully landing flaps zero I taxied to the gate without further incident.


Synopsis: Q400 flight crew reported diverting after a flap malfunction while on approach and while handling the situation; may have also potentially went over the airspeed restrictions for the stuck flap configuration.