Date: 202004
Local time of day: 0601-1200
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: Climb
Airspace: Class B ZZZ
Aircraft component: Landing Gear
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Communication Breakdown
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Aircraft Equipment Problem Dissipated; Flight Crew Overcame Equipment Problem
Contributing factors: Aircraft; Procedure
Primary problem: Procedure

Narrative: Captain and First Officer; who were serving as the flight crew between ZZZ and ZZZ1 experienced a gear malfunction when the landing gear failed to retract when the landing gear selector was selected 'up.' It was subsequently determined that the Landing Gear Alternate Release was not fully closed.Prior to flight it was determined that the Park Brake pressure was below 500 psi. Per the originating checklist; the crew referenced the flight manual; section 7; Supplementary Normal Procedures.After referencing the Low Park Brake Pressure section of section 7; the crew followed Procedure 2. While performing these steps; both crew members exited the crew compartment in order to actuate the Brake Auxiliary Pump. Once sufficient park brake pressure had been achieved; the crew returned to the flight compartment and continued their preparations for departure. During a subsequent crew debrief; it was determined that the crew had overlooked step 3; which instructed the closure of the Landing Gear Alt Release Door.After takeoff when the gear failed to retract; the crew immediately determined the cause of the failure was due to the Landing Gear Alternate Release not being fully closed. The crew continued the departure and completed the remainder of the after takeoff checklist. The crew continued the climb to their initial altitude of 10;000 feet where they leveled off and maintained airspeed below 200 knots. The crew then referenced the checklist and completed the 'Landing Gear Fails to Retract' checklist; which resulted in the successful retraction of the landing gear. The flight continued to ZZZ1.Modify 'Low Park Brake Pressure' procedure 2. It is very easy to overlook step 3 due to frequent use of capital letters in steps 1; 2; and 3. Consider using bold text for step 3. Also; add a step 8 to verify step 3. When the crew needs to exit the aircraft; it creates a sense of urgency upon returning to meet departure time. As a result; a returning crew can be eager to continue their flight preparations and seeing they have completed step 7; believe they have successfully completed the checklist.




Synopsis: Q400 First Officer reported landing gear failed to retract when selected up; caused by the landing gear alternate release panel cover which was not properly closed.