Learjet 35
Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor
Flight Crew Last 90 Days 30; Flight Crew Total 12300; Flight Crew Type 3500
Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Landed in Emergency Condition; Flight Crew Diverted
Aircraft
While at 38000 feet cruising altitude; 35 min into the flight; the LEFT GEN annunciator came on and simultaneously the autopilot disconnected and the MACH TRIM warning sounded. A Second or so after; electrical SMOKE began to pour out from behind the instrument panel. The amount of smoke was significant enough to fill the cabin and we immediately performed the CABIN/COCKPIT FIRE; SMOKE; OR FUMES memory item checklist. We donned our O2 masks and advised Center. We told them we would need to do an emergency descent and asked for vectors to the nearest suitable airport. We were cleared to descend to 4000 feet and given a heading of 030. We brought the throttles to idle extended spoilers and gear and did a rapid descent towards ZZZ airport. During the descent we turned off the LEFT GEN and reduced as much of the electrical load as possible. The smoke intensity appeared to decrease as we descended. We were asked if we needed assistance and we replied that we would like to have fire equipment standing by but there was no visible signs of fire. We were then handed over to Tower and cleared to land. We were able to complete a before landing checklist and the landing was normal. We exited the runway and the fire crews met us on the taxiway. After performing an emergency shutdown and exiting the aircraft we immediately disconnected the batteries to eliminate all electrical sources from the aircraft. The fire crews after making sure we were ok scanned the instrument panel with a thermal camera and detected two hot spots behind the panel. We both did have some discomfort and some burning/dryness in our mouths; throats and lungs from the smoke inhalation; but after some fresh air and some water we were feeling better.
LR35 Captain; cruising at FL380; experienced a left generator light along with autopilot disconnect and a Mach trim warning. Within seconds smoke began to pour from behind the instrument panel and oxygen masks were donned. An emergency descent was initiated using gear and spoilers. Vectors were received to the nearest suitable airport for a normal landing.