Date: 201712
Local time of day: 0601-1200
Location: ZZZ.ARTCC, US
Light: Dawn
Aircraft: Challenger CL600
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Troubleshooting; Distraction; Human-Machine Interface; Time Pressure; Workload
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Security; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Overcame Equipment Problem; Flight Crew Became Reoriented
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: We left the hotel late due to the fact that the taxi service the hotel had called hours prior to our departure arrived about 15 minutes late. When we got to the airplane the air hooked up to low pressure point was not adequate to warm the airplane for passenger comfort. We started the APU; but really didn't get the airplane warm in the short time we were at the gate. We taxied out and took off without delay or issues. We were aware the cabin temperature was not optimal; but we figured once we were flying this would improve rapidly; however the airplane was cold and the temperature stayed cold even though we tried to work the settings to increase the heat. After several consults with the flight attendants we still had low temperatures in the front. One of the passengers was one of the pilots that flew the plane in the night before and he volunteered to come to the flight deck and show us how he got it to work the night before. Capt allowed him access to the flight deck to show how he worked it the night before. In reality nothing we had not tried before. The temperature only slowly improved during this flight. After we arrived the aircraft was heated using the jet bridge heat and we didn't have any problem on the next flight. It appears that the cold soaked airplane took longer to heat up than we anticipated. The issue of flight deck issue was raised at the end of last flight on trip by the First Officer after he had discussed this issue with another pilot. The following mistakes were made by Captain on this issue. Even though the pilot is company employee he didn't have jump seat form with information checked. Access to flight deck was granted without looking through peephole; because captain assumed he knew the pilot and recognized his voice on intercom.Threats; Captain new on CRJ 900. Undesired status is that I gave access during flight to another [company] pilot during flight and quite frankly may not have adhered to the security directive as to not opening the door to flight deck accept for crew members working the flight. Captain was trying to see if there was a better way to get the airplane to get warmer faster and tried to use another resource on the airplane. Captain preoccupied with issue and forgot protocols. Captain logic: We have a non-safety issue; I would like to resolve it. First officer (11 years on aircraft) and I (2 months on airplane) could not get it to heat up fast. Maybe the guy that flew it last night knows something we don't. So use the resource. It is company employee so should be no threat to safety.Captain will talk to several other pilots to learn more about the air conditioning system beyond what is in the manual. on all the flights following this one flight we had no real problem with cabin temperature except maybe that it was to warm.Captain will not let anyone enter the flight deck unless it is an emergency and not let guard down on something like this. It was as the captain assumed it was and no real threat existed but it is not the smartest way to do this.Next time captain will stay on the flight deck and just have the flight attended relay all the information. There was no need to open the door; the employee could have even just relayed on the intercom.




Synopsis: CL600 Captain reported a security violation by permitting flight deck access without following proper protocol.