Inspect Engine Ignition Systems Flashcards
What is the main advantage of a magneto ignition system over a battery ignition system for an aircraft reciprocating engine?
A magneto has it’s own source of electrical energy, and is not dependent upon the battery
What is the function of the capacitor in a magneto?
The capacitor minimizes arcing at the breaker points, and it speeds up the collapse of the primary current as the breaker points open
What happens in a magneto ignition system when the ignition switch is placed in the off position?
The primary circuit is connected to ground
What is checked when a magneto is internally timed?
Internally timing a magneto consists of adjusting the breaker points so they will open at the instant the rotating magnet is in its E-gap position, and the distributor rotor is in position to direct the high voltage to cylinder number one
In what position should the ignition switch be placed when using a timing light on the magnetos?
In the Both position
What type of ignition system is used on most turbine engines?
High-intensity, intermittent-duty capacitor discharge ignition systems
What is the E-gap in magneto timing?
The E-gap angle is the position of the rotating magnet when the primary current flowing in the magneto coil is greatest.
How many ignites are used with most turbine engines?
Two
What are two types of ignition systems used in turbine engines?
High-voltage systems and low-voltage systems
With which type of turbine-engine ignition system is a glow plug ignitor used?
A low voltage system
How is the strength of the magnet in a magneto checked?
The magneto is put on a test stand and rotated at a specified speed. The breaker points are held open and the primary current is measured
In what position is the magnet in a magneto when the greatest change in flux density in the coil core takes place?
It is a few degrees beyond its neutral position. When it is in this position the breaker points open open and the primary current is interrupted
In what position is the magnet in a magneto when the breaker points begin to open?
In its E-gap position just a few degrees beyond its neutral position
What malfunction in the ignition system would cause an aircraft reciprocating engine to continue to run after the ignition switch is placed in the Off position?
The ignition switch is not grounding the magneto primary circuit
What kind of equipment is used to test an ignition harness for a reciprocating engine?
A high-voltage electrical leakage detector
What is an All-Weather spark plug?
A shielded spark plug that has a recess in the shielding in which a resilient grommet on the ignition lead forms a watertight seal
What is meant by the reach of a spark plug?
The length of the threads on the spark plug that screw into the cylinder head
What is the difference between a hot spark plug and a cold spark plug?
A hot spark plug has a long path for the heat to travel between the nose core insulator and the spark plug shell.
What is the advantage of fine-wire spark plugs over massive electrode spark plugs?
Fine-wire spark plugs have a firing end that is more open than that of a massive electrode spark plug.
Why is it important that the spark plugs be kept in numbered holes in a tray when they are removed from an engine?
To keep track of their firing order
Why is it important that a torque wrench always be used when installing spark plugs in an aircraft engine?
If the spark plugs are not put in tight enough there is the possibility of a poor seal. Too tight they might crack
What kind of gage should be used to measure the electrode gap in aircraft spark plugs?
A round wire gage