Date: 201504
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: Citation V/Ultra/Encore (C560)
Operator: Fractional
Operating under: Part 135
Flight phase: Parked
Aircraft component: Switch
Component problem: Malfunctioning
Reporter organization: Fractional
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Confusion; Workload; Troubleshooting
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft; Procedure; Human Factors
Primary problem: Aircraft

Narrative: New [Maintenance] Controller Y received a call from [flight] crew [of Aircraft X; a CE-560]. He was unsure of what action [to take] and the other controllers were heavily occupied; I [Controller X]; requested he standby. Once able I researched the discussion between Controller Y and Assistant Chief Pilot (ACP) on Duty. Early morning; the crew submitted the following discrepancy.... 'Battery disconnect switch does not disconnect battery.'....[Approximately an hour later]; I notified the following to the crew..... Battery disconnect switch does not disconnect battery. [Shortly after]; I followed up with these additional questions.... 'In addition to the question posed are all the Circuit breakers set?  What was the battery voltage?  Provide these answers in the next 15 minutes so we can begin to seek the cause. [Approximately] 45-minutes later; received this reply from the crew... All of the pertinent information is listed in the AOG.  Battery voltage was normal and Circuit Breakers (CB) were in.At approx. two hours later; the Assistant Chief Pilot (ACP) replied with the following response....'crew would not reply to technical Questions and provide direct answers to questions to assist in troubleshooting.  ACP provided the following:I have had a conversation with the crew. While not specifically directed by a checklist; the crew did check the battery disconnect as a precaution. We acknowledge that this check is not specifically required or the parameters set for a pass or fail. However; the battery was on and connected with the disconnect switch engaged and per the pilot training manual the disconnect should remove power from the aircraft when those conditions are met. There was no change in the cockpit in this case. The crew of another CE-560 aircraft tried the same procedure (battery on and connected; disconnect on) and for them it resulted in a dark cockpit. I consulted with Chief Pilot and came to the conclusion that it is very likely that the disconnect is not working. If that is the case; the disconnect switch is a checklist item in both abnormal and emergency checklists and we need to get it looked at. All circuit breakers were in and battery voltage was the standard 24 volts. The crew did try to start the engines and see if system voltage would activate the relay; but there was no change. It appears that the relay that energizes open to disconnect power from the system is stuck closed; and should we have a stuck starter or overheated battery there could be a definite issue.  Additional information... No the aircraft has not flown. No; there was not an emergency condition for the crew to toggle the battery disconnect and there is NO checks for this by the crew on preflight or any other 'Normal' checklist; other than the EMER procedures checklist.  This crew wrote this up; we; Maintenance Controllers brought it to the ACP and the ACP and the Chief Pilot (CP) had another crew 'try' this on another aircraft after it flew; and it caused the cockpit to go dark. Chief Pilot is having the crew on CE-560 (Aircraft X) fire engines up and then reattempting the disconnect... if it still does nothing they will want maintenance to fix it. They can now do invalid checks and break?  [Recommend] Not Allow crews to test items that they do not have policy; procedures and or direction to accomplish. Or; when they do; to provide transparency and direct answers to questions so complete and adequate maintenance can be conducted to assure there were no other issues 'caused' by the crew that could manifest electrical problems left undiagnosed due to lack of information from the identifying crew. Flight canceled. Battery Disconnect.




Synopsis: A Maintenance Controller was informed by a CE-560 flight crew that the Battery Disconnect switch would not disconnect the aircraft battery. Controller also noted the flight crew would not reply to technical questions to assist in troubleshooting. Concerns raised that the relay that energizes open; to disconnect power from the system was stuck.