Date: 201201
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Weather elements / visibility: Snow
Light: Night
Aircraft: Dash 8-300
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Parked
Aircraft component: Engine Control
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Other / Unknown; Fatigue; Time Pressure; Situational Awareness
Second reporter function: Technician
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Maintenance
When detected: Routine Inspection
Result: General Maintenance Action
Contributing factors: Logbook Entry; Aircraft; Chart Or Publication; Company Policy; Human Factors
Primary problem: Human Factors

Narrative: While performing gate maintenance duties in the morning; I was [also] tasked with shuttling two employees back to the hangar after they delivered a Routine Overnight (RON) aircraft to the gate at approximately XA:45 hours. While dropping the two off at the hangar; I was contacted by the On-Duty Supervisor and advised that Avionics Technician Y would be accompanying me back to the gate; due to a maintenance problem with Aircraft X.On arrival at the gate at approximately XA:55 hours; the Pilot in Command (PIC) of Aircraft X advised that the Beta Lockout System would not test. After contacting ZZZ1 Maintenance Control; we agreed to remove the forward left pressure panel and verify that the toggle switches associated with the system were in the 'normal' position. Avionics Technician Y and I removed the panel. Technician Y returned the toggle switches to the 'normal' position. The PIC re-tested the system and he related in substance that the system was testing properly. As Technician Y began to re-install the panel removed; I contacted ZZZ1 Maintenance Control to report our Maintenance action and complete the logbook entry as directed by ZZZ1 Maintenance Control.After completing the logbook entry; I exited the aircraft where I immediately went forward and conducted a hasty exam of the panel removed and the DC contactor bay door above it; which had been opened in order to ensure they were secure. The door was closed and latches secured and the panel was flush and there were no apparent unfastened screws raised out of their holes. Feeling satisfied that Technician Y and I had done the best job possible; working in the extreme cold; I cleared the scene at approximately XB:40 hours.Later that day; at approximately XC:30 hours; while on duty at ZZZ Maintenance Base; I was approached by Technician Y and he told me that he had failed to install two screws in the panel removed on Aircraft X earlier that day. He told me that he had found two screws in his pocket after he returned from gate duty.As I was checking behind Technician Y and performing a hasty exam of the doors and panels; I did not devote the proper amount of time and attention to verify that all of the screws were in their places. Even after bending over to look past the curvature of the airframe; I still missed the two (2) fasteners. Technician Y reported the event to the On-Duty Supervisor and a check of the aircraft after arriving in ZZZ2 revealed two missing fasteners on the panel.I am certainly going to be more careful in the future about storing hardware. I have already placed a stash of parts bags in the Maintenance van for use when removing panels in the future. I will communicate more frequently during the task with coworkers involved to ensure we are doing what we can in a safe and complete manner. I will encourage open discussion and cultivate a work environment which promotes free exchange of suggestions for good work practices during maintenance actions to ensure we are cross-checking each other to prevent oversights like mine.


Second narrative: Avionics [technician] was working on an aircraft in the hangar and Mechanic X assigned to the gate was pulling double duty. Mechanic X was also doing chauffeuring of personnel that bring the plane to the gate; back to the hangar. The temperature at the time was 28 degrees Fahrenheit and winds gust of 35 MPH and when Mechanic X was bringing a [Maintenance] crew back [to the hangar]; the pilot called for a Mechanic. The Supervisor on-duty told me someone had to go with Mechanic X; so I went with him to the gate and the pilot said the Beta System was not working. The plane in question was involved with a lighting strike the night before. I was one of the Avionics' Technicians that went to look at the plane in ZZZ3 and I knew the Beta was deactivated and was on an MEL and when the Technician on days signed it off; he did not put the [Toggle] switch back into the proper position. So we ask Maintenance Control if they want us to open the pressure panel to look at the switch. We found the switch in the wrong position; we put the [switch] into the correct position and after testing the system I started to put the panel back on; and Mechanic X went into the aircraft to do the logbook. He came back out to give me his screws to put in and I told him to help me because it was cold; [but] he did not want to help me. He wanted to do the logbook. While I was installing the panel; Mechanic Z came over from the hangar and gave me a Screw-Gun and some gloves and I finished installing the panel. After; I went into Operation's and after my hands warmed up a little; I put my hand into my jacket and found two screws; and when I got back to the hangar I told the Supervisor that I left some screws out. Mechanic X was in a rush to do the logbook; to get the plane out on time. Suggest don't let one Technician go and sign-off the logbook before the job is done and when it is a rush job; make sure both mechanics look at the job.


Synopsis: Two Technicians describe their involvement with reinstalling a forward left pressure panel (121AL) on a DHC-8-300 aircraft; after checking the toggle switches associated with the Beta Lockout System. Two screws used to secure the panel were not reinstalled.