Text 4. Fire Protection

A single loop fire detection system and a two shot extinguishing system shall be installed in each engine nacelle.

The fire protection controller installed in the overhead panel shall provide the following functions for each engine test: failure indication, fire / overheat indication, extinguishing.

Detection. A single loop fire and overheat detection system shall be installed in each engine compartment. Quick acting fire detectors in the combustion, turbine and tailpipe sections of the turbine engine installation shall ensure prompt detection of fire or overheat.

The fire detection sensor shall consist of a highly flexible cable, whish will actuate an alarm signal when exposed to any temperature above a definite pre-established level (thermal-fixed temperature-type sensor). Under fire conditions the response time of the firewires shall be less than five seconds. The cable shall be sensitive to temperature changes, survive temperatures up to 2,000*F (1,093*C) and withstand hammering and bending.

An alarm shall be activated either when a short section of the cable is heated to a relatively high temperature by fire or when an overheat condition increases the ambient temperature in the compartment, heating a longer section of the entire cable.

The engine fire detection system shall be installed in a single loop configuration. Each loop consists of four single firewire-elements. Two elements are installed at the forward doors, two elements are installed in the rear compartment. A control unit monitors the four firewire-elements in the nacelle.

If the control module receives a fire signal from either detector on that engine, an audible and visual alarm will be generated by the fire protection controller.

The system indicates fire immediately after ignition and remains on for the duration of the fire, indicates when the fire is out (warnings off) and indicates re-ignition of the fire.

The system shall not cause false warning under any flight or ground conditions.

Exercise 21. Read, translate und entitle text 5. Write out the new terms.

Text 5

Six infrared-sensitive fire detectors are located in the engine compartments: three detectors for the left engine and three for the right engine.

All three detectors on each engine are electrically connected to trigger two solid-state detection amplifiers. A high alarm level is required to trigger the detectors. If a fire exists, the amplifiers are triggered and cause two red flashers on the glareshield to flash and the appropriate red fire annunciator to illuminate. If optional fire extinguishing equipment is installed, the control buttons are placed in the glareshield and one fire extinguishing cylinder is installed in each main gear wheel well.

The cylinder is fired by pressing the control button; only one discharge is possible. The squib assemblies on each cylinder are hot-wired. Care must be exercised to avoid unintentional firing of the squibs and cylinders discharge. A test circuit is incorporated for the detectors and amplifiers, squibs, and annunciator lights.

Exercise 22. Look at fig. 1.3 and make sure you remember the terms concerning the topic “Fire Extinguishing System”.

Exercise 23. Speak on Fire Extinguishing System