Halon 1211 or CO₂   are the extinguishing agents used on these fires. However, when a fire in an aircraft cannot be extinguished with Halon 1211 or CO₂, the use of AFFF to prevent further damage outweighs the disadvantages. Internal Engine Fires Internal engine fires usually result when residual fuel is dumped into the engine on shutdown. When starting equipment and qualified starting personnel are immediately available, these fires may be controlled by windmilling the engine. If this procedure fails or if the equipment  and  personnel  are  not  available,  an extinguishing agent must be directed into the engine. Halon 1211 or CO₂  is the primary agent for internal fires. Application of Halon 1211 or CO₂    must be accomplished at a distance so that the Halon 1211 or CO₂  enters the fire area in gaseous form. CAUTION When CO₂ or Halon 1211 is expelled directly into an engine, thermal shock may result, causing engine damage. High bypass turbofan engines require unique techniques to extinguish engine core fires. Aircraft Engine Fires Use the following procedures for extinguishing fires in high bypass turbofan engines: 1. Engine accessory section fire. a. Halon 1211 or CO₂ may be introduced into the engine accessory section area through the access doors located on the aircraft engine cowling. b. When the fire is under control, one fire fighter in full protective clothing (hot suit) will open the engine cowling. An AFFF hand line should be used to provide fire protection to the fire fighter. NOTE:  A screwdriver may be required to open the engine cowling due to the restrictions of proximity gloves. 2. Engine fire turbine section engine core. When the engine is shutdown, apply Halon 1211 or CO₂, and if required AFFF, into the aircraft exhaust section only until the fire is extinguished. 3. Engine fire in compressor section engine core. CAUTION The source of this fire will probably be burning titanium, and can be identified by the sparking effect of this material when it is burning. This fire is potentially destructive and may possibly burn through the engine casing if immediate fire suppression measures are not taken. a. Halon 1211 or CO₂ may be introduced into the engine intake, exhaust, or accessory section. b. When the fire is under control, one fire fighter in full protective clothing (hot suit) will open the engine cowling. An AFFF hand line should be used to provide fire protection to the fire fighter. c. When the engine cowling is open, apply AFFF to both sides of the engine casing to complete extinguishing and provide additional cooling. Electrical and Electronic Equipment Fires In combating electrical fires, you must secure the source of electrical power. For combating class C fires, Halon 1211 or CO₂  is the primary agent, and should have no adverse effect on electrical or electronic components. WARNING Halon 1211 may be used in a small electronics compartment to make the atmosphere inert, provided fire fighters do not enter the compartment, or enter it with a self-contained breathing apparatus. Do NOT use CO₂  to make the atmosphere in an electronics compartment inert, as it may produce a spark. TAILPIPE FIRES When a fire occurs in the tailpipe of an aircraft during shutdown, the aircraft engine should be started by authorized personnel in order to attempt extinguishing  through  exhaust  pressures.  If  this operation does not extinguish the fire, the following should be performed by the crash crew. 1. Direct fire-extinguishing agents Halon 1211 or CO₂  into the tailpipe. 2. If fire is not extinguished by the above methods, direct the stream of extinguisher agent into the intake duct. 12-19