Incident Overview
A pilot encountered heavy black smoke in the cockpit and cabin after retracting the landing gear. The source of the smoke was traced to smoldering wire insulation and fire shield material, which had been ignited by hot exhaust gas escaping from a broken exhaust manifold. The exhaust gas had melted the sealant from several areas of the firewall where hoses, wires, and other components passed through to the cockpit area.
Emergency Declaration and Pilot Actions
The pilot declared an emergency with the airport tower controller. To mitigate the smoke, the pilot opened the pilot's vent window, extended the landing gear, and reduced engine power. These actions diminished the smoke somewhat, but the smoke became more intense each time engine power was reapplied.
Landing
Due to the increased smoke, adequate power for speed and runway alignment could not be obtained. Consequently, the pilot accomplished a hard, off-runway landing.