Beechjet 400
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Workload; Troubleshooting; Time Pressure; Physiological - Other
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Aircraft; Human Factors; Procedure; Staffing
Assigned Pilot-in-Command for [a] revenue trip. Upon arrival at the departure airport; I noticed there was one lineman only who would be assisting with aircraft ground operations to include fueling; Ground Power Unit (GPU) usage; coffee/ice/papers; and other duties. As routine practice; I delegated my First Officer the duty of pre-flighting the aircraft exterior and interior. I calculated W&B and performance and took the coffee pot out of the jet to be filled. During this time; our passengers showed up 40 minutes early. While my First Officer was in the cockpit still preflighting; I greeted the customers and was in the process of putting the coffee; ice; and newspapers on the jet when my First Officer brought to my attention the R F/V and R H/V switch was not working properly to reopen the valves after the fuel system test. I confirmed the switch was not functioning properly by depressing the R F/V and R H/V OPEN/CLSD switch. No movement of the valves indicated. I asked my First Officer if he had pushed another other guarded/non-guarded switches. His reply was 'No.' To troubleshoot; I called maintenance. I followed the guidance from maintenance in attempt to clear the discrepancy. It was determined that the valves were not showing movement because of incorrect switch activation in the fire protection system. After visually inspecting the fire bottle pressures in the aft baggage compartment; I saw the fire bottles had been discharged. I then started communicating with company to recover the grounded flight mission.This incident could have been mitigated had my First Officer followed the Pre-Flight Checklist. If a mistake had been made; having the integrity to admit and communicate early perhaps would have prevented bottle discharge. Unfortunately since there was limited ground personnel available to help us 'ready' the jet; my attention was not directed on observing the cockpit pre-flight checks. This is the first time in years of flying this aircraft to have this occur.
A BE-400 Captain reported that during preflight checks they were unable to open the engine fuel valve because the engine was fire bottle discharged.