Part 4/11:
Fire safety is paramount in aviation, and the TriStar was equipped with multiple detection and suppression systems. Cargo compartments were classified under international regulations with various fire protection classes, each determined by visibility and accessibility. The Class D designation indicated that the C3 cargo compartment of the L1011 was considered fireproof, lacking smoke detectors and built-in fire suppression systems. The design assumed that limited airflow would starve a fire of oxygen; however, the compartment's large size meant that this assumption was flawed, a fact that would soon become crucially evident.