AMT Reciprocating Engine Ignition Systems 2

Question 1

What is the primary purpose of the impulse coupling on a magneto?

Accepted Answer

Provide a retarded and intensified spark during engine starting

Answer

The impulse coupling temporarily retards ignition timing and snaps the magnet past the neutral position to produce a strong spark at low starting speeds.

Question 2

Which ignition system component prevents a spark plug from firing at the incorrect time due to residual magnetism?

Accepted Answer

Condenser

Answer

The condenser absorbs the collapsing magnetic field energy, preventing arcing at the breaker points and ensuring sharp primary circuit cutoff.

Question 3

On a dual-magneto ignition system, the 'BOTH' position on the ignition switch is used during normal flight because it:

Accepted Answer

Reduces fuel consumption by providing complete combustion

Answer

Firing two spark plugs per cylinder from separate magnetos produces more complete combustion, improving efficiency and providing redundancy.

Question 4

A magneto's 'E-gap' refers to the position of the rotating magnet when:

Accepted Answer

Magnetic flux through the coil core is changing most rapidly

Answer

E-gap (efficiency gap) is the rotor position at which flux change in the core is at maximum, generating the highest possible primary voltage before points open.

Question 5

What type of spark plug would most likely be used in a high-compression aircraft engine to resist fouling?

Accepted Answer

Short-reach, cold heat range plug

Answer

Short-reach, cold heat range plugs transfer heat away quickly, reducing pre-ignition risk in high-compression engines while the short reach avoids interfering with pistons.

(AMT) Aviation Maintenance Technician Practice Test

(AMT) Aviation Maintenance Technician Practice Test

AMT Reciprocating Engine Ignition Systems 2