AD/B737/39 - APU Fire Detector Element

Inspect to ensure a Walter Kidde fire detector element is installed in the APU compartment. This inspection may be performed by viewing through the APU cooling air exhaust outlet. The Walter Kidde element is protected by a perforated shield surrounding the length of the element. If the perforated shield is not seen, open the lower APU shroud and verify that for 737-300 and 737-400 series aircraft, the fire detector element installed is Boeing P/N 10-61096-316 / Walter Kidde P/N 894481, and for 737-100 and 737-200 series aircraft, the fire detector element installed is Boeing P/N 10-62061-6 or P/N 10-61096-116.