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During the final approach to land on Runway 9 at Tallahassee Regional Airport, Federal Express (FedEx) Flight 1478 crashed into a forest about a mile short of the Runway 9 threshold. The Precision Approach Path Indicator (PAPI) device servicing the runway was supposedly showing four red lights during this final approach, providing colour-coded information that the approach was too low for a safe landing. The First Officer, piloting Flight 1478, had a colour vision defect, and the crash has raised the question of whether colour vision standards in aviation should be more stringent than they currently are. In this paper, we argue that the crash of FedEx Flight 1478 raises the more fundamental question of whether colour-coded information should be used at all in aviation. The basis of our argument is this puzzle: While the First Officer, piloting, had defective colour vision, the Captain and the Flight Engineer, both actively involved in the approach to land of Flight 1478, had normal colour vision, yet did not seem to see, and certainly did not make use of, the colour-coded information supposedly provided by the PAPI device. We describe how the National Transportation Safety Board’s (NTSB) Report implicitly acknowledges and attempts to explain this puzzle. We propose an alternative explanation of this puzzle, and conclude by considering the implications of this alternative explanation for colour vision standards in aviation.