Investigation of Flight Data Recorder Fire Test Requirements

This report evaluates fire test methodologies for aircraft flight data and cockpit voice recorders. The current fire test requirement consists of a 30-minute exposure to a propane burner calibrated to the heating conditions created by a jet fuel fire. A comparison was made of the internal temperature of flight recorder models subjected to the propane burner standard and a jet fuel fire. The internal temperature was approximately 40 percent higher during the fuel fire tests which were 6-8 minutes in duration. Although the fuel fire duration was limited, it appears that a 60-minute propane burner test exposure is a feasible and conservative means of evaluating the thermal resistance of a flight recorder subjected to a 30-minute fuel fire. An additional fire test condition 500 deg F10 hours has been proposed to simulate a smoldering fire which may persist for a long period of time at a remote site. A state-of-the-art magnetic tape of the cockpit voice recorder was subjected to this condition in an oven and failed the test, demonstrating the severity of this exposure environment. Fire resistance, Fire tests, Flight data recorder, Cockpit voice recorder.