MIL-DTL-32027

Abstract

This specification covers the requirements for the manufacture and acceptance of the Dry Bay Fire Extinguisher Gas Generator, GGU-15A/A, referred to herein as "gas generator". <b><u>Intended Use:</u></b> The gas generator is designed for use in the F/A-18E/F Aircraft Dry Bay Fire Suppression System. The Dry Bay Fire Suppression System is designed to protect the dry bays under fuel tanks 2, 3 and 4. The gas generator is for military aircraft use and has no equivalent commercial application. When the system is armed, all the gas generators are automatically discharged upon detection of a fire/explosion; no aircrew interaction is required. Six (6) 33300-301 gas generators are installed in various locations within the dry bays. The gas generators are connected to a Fire Suppression Control Alarm (FSCA), which is connected to Optical Fire Detectors (OFDs). Upon sensing a fire, the optical fire detectors transmit a signal to the FSCA. The FSCA is programmed to send electrical firing pulses in a pre-determined timing sequence to all gas generators. The gas generators, when initiated, the main propellant combustion produces inert gases comprised mainly of nitrogen, carbon dioxide and water vapor. The gases vent radially through orifices in the body of the gas generators. These inert gases achieve fire extinguishment in the dry bays by reducing the oxygen level below that required for sustaining combustion. The gas is non-ozone depleting, non-toxic and has a minimal corrosive effect on the aircraft dry bay structure. Once gas generators are fired, the system can only be restored to operational use by replacement of functioned units. These gas generators were developed to function in the F/A-18E/F dry bays. Of major importance is the structural over pressure limits of the bays. Changes to the gas generators resulting in increased performance, faster bum times or greater pressure output could result in the structural failure of the airframe components during an inadvertent actuation of the system. <br>