Narrative:

Air crew began smelling fumes and shortly after saw a haze in the cabin. Returned to airfield immediately. Upon landing; myself and another maintainer began trying to isolate the source of fumes and smoke. After an hour of search no obvious suspect components could be located. At that time two individuals who fly for the company approached the aircraft; one is rated in this aircraft the other is not. They intended to take the aircraft flying with myself and the other maintainer sitting in the back to 'see what happens' in the air. I and the other maintainer agreed this would not be the case; they would not take the aircraft up especially with us on board. I informed them that it was reckless; our inspection of the aircraft was not complete and that we could use ground power if needed to power systems. My warning was not heeded; they continued to preflight. At that moment the other maintainer had continued pulling floor boards and discovered a large diode that was severely burned; the obvious culprit. I informed the 'pilots'; I say this loosely; and they finally ceased their intent to fly. Later they proposed the idea of flying to our home base; 4.5 hours away; to get repairs done. I informed them once again that the aircraft was down! The maintenance crew had still not been able to see the full extent of the damage and that more inspections would need to be conducted. This incident was just an example of poor judgment on the 'pilots' behalf. It was disturbing that any individual would want to fly an aircraft with serious electrical issues and even moreso that they would expect two individuals to ride with them. I believe if the fault had not been discovered when it was they would have gone and more than likely had a fire on the aircraft; increasing the probability of a major incident or crash. The reward was not there; the risk too great. I say this in a maintainer roll; but I am also air crew on board; fulfilling two rolls within the company. I am very familiar with CRM and it was put aside this day by two dangerous individuals.

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Original NASA ASRS Text

Title: BE200 returns to departure airport after electrical fumes are detected in the cabin. Maintenance technicians attempting to troubleshoot the problem are advised by company pilots that they will take it flying and the mechanics can troubleshoot airborne. The mechanics decline. A failed diode is eventually found to be the culprit.

Narrative: Air crew began smelling fumes and shortly after saw a haze in the cabin. Returned to airfield immediately. Upon landing; myself and another maintainer began trying to isolate the source of fumes and smoke. After an hour of search no obvious suspect components could be located. At that time two individuals who fly for the company approached the aircraft; one is rated in this aircraft the other is not. They intended to take the aircraft flying with myself and the other maintainer sitting in the back to 'see what happens' in the air. I and the other maintainer agreed this would not be the case; they would not take the aircraft up especially with us on board. I informed them that it was reckless; our inspection of the aircraft was not complete and that we could use ground power if needed to power systems. My warning was not heeded; they continued to preflight. At that moment the other maintainer had continued pulling floor boards and discovered a large diode that was severely burned; the obvious culprit. I informed the 'pilots'; I say this loosely; and they finally ceased their intent to fly. Later they proposed the idea of flying to our home base; 4.5 hours away; to get repairs done. I informed them once again that the aircraft was down! The maintenance crew had still not been able to see the full extent of the damage and that more inspections would need to be conducted. This incident was just an example of poor judgment on the 'pilots' behalf. It was disturbing that any individual would want to fly an aircraft with serious electrical issues and even moreso that they would expect two individuals to ride with them. I believe if the fault had not been discovered when it was they would have gone and more than likely had a fire on the aircraft; increasing the probability of a major incident or crash. The reward was not there; the risk too great. I say this in a maintainer roll; but I am also air crew on board; fulfilling two rolls within the company. I am very familiar with CRM and it was put aside this day by two dangerous individuals.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.