Cessna 150
Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 100; Flight Crew Total 1012; Flight Crew Type 450
Confusion; Distraction; Troubleshooting; Workload
Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Flight Crew Returned To Gate; General Declared Emergency; General Maintenance Action
Aircraft
Trying to turn panel lighting off when smoke erupted from knob that was being turned. Light smoke with electrical smell was visible about 1 minute after occurrence and elected to proceed back to the ramp. No other smoke was indicated on the 3 minute taxi back to the ramp. Aircraft engine was shut down and aircraft parked with no fire or burnt wire being noted. Fire trucks were standing by. What caused the problem I believe was the knob not being used in years and the switch being overworked. To prevent a recurrence would be to not move the knob as well as having the knob and electrical wiring repaired and to working order. Also; to use the checklist and to evacuate if the need arises.
A C150 panel light knob emitted smoke as it was turned so an emergency was declared; the pilot returned to parking and secured the aircraft.