The three general areas of aircraft-fire investigations are (1) persons, including but not limited to flight crew, supervisors, maintenance personnel, operations personnel, air traffic controllers, and witnesses; (2) material, including all parts, components, and support facilities; and (3) records, including flight logs, training documents, and maintenance data. Investigation consists of a thorough crash-scene study, hardware inspection, analysis of laboratory tests, and witness statements, notes, maps, diagrams, and photographs. If an aircraft fire looks suspicious, the Federal Aviation Administration may contact the local fire investigator for assistance. It is important to determine whether the fire started in flight or on the ground, perhaps after crash impact. Research on the effects of smoke and gases from controlled fires can establish whether death in an aircraft fire may have been caused by certain toxic materials present on the aircraft. Four footnotes, seven bibliographic entries, and tabular research data are provided.