Check on Engine Fire Extinguisher System
1.Equipment Needed
An avometer.
2.Preparations
·Remove rear cowlings.
·Remove the cable plugs of the explosion tubes of two fire extinguishers.
·Remove the protection caps of the fire extinguisher system from the instrument panel.
·Switch on heliborne power system.
3.Check
At least 2 operators are needed in the following check(one in the cockpit and the other conducting the check).
Checking Procedures:
·Press the four buttons of the fire extinguishers in turn.After pressing each button,check voltages of binding posts A and C,B and C,or 1 and 3,2 and 3(markings vary based on the type of cable plugs)of the cable plug of the corresponding explosion tube:
Press the first explosion button of left engine:the cable plug of yellow explosion tube of left fire extinguisher;
Press the second explosion button of left engine:the cable plug of yellow explosion tube of right fire extinguisher;
Press the first explosion button of right engine:the cable plug of gray explosion tube of right fire extinguisher;
Press the second explosion button of right engine:the cable plug of gray explosion tube of left fire extinguisher.
·Check(general conditions,reliability,fastening,cracks,erosion and rust)
cable plugs of explosion tubes
cable plugs of pressure switches
fire extinguishers(check the pressure with a pressure gauge based on the labels on extinguishers)
distribution pipes of fire extinguishers
fire extinguisher nozzles on the rear fire proof wall
Check if there is any crack or fracture on the corners of the mounting bases of fire extinguisher bottles.If any,replace the mounting base(s).
4.Finishing Touches
·Switch off heliborne power system(generators and battery).
·Re-install the protection caps of fire extinguisher system onto the instrument panel.
·Remove the testing unit.
·Connect the cable plugs of the explosion tubes of two fire extinguishers.
·Re-install rear cowlings.