Reciprocating Engine Ignition Systems Flashcards
7 cards from real AMT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Reciprocating Engine Ignition Systems flashcards as text
Which spark plug condition indicates detonation has occurred in the cylinder?
Answer: Shiny, eroded or pitted electrodes with possible aluminum deposits
Detonation causes extreme pressure spikes that erode and pit the electrodes; aluminum deposits may appear if the piston crown is damaged by detonation.
What is the result of setting magneto timing too far advanced?
Answer: Pre-ignition risk, detonation, and possible engine damage
Over-advanced timing fires the spark too early, so combustion pressure peaks before the piston reaches TDC, creating a reverse force that can cause detonation and severe engine damage.
During inspection, you notice a crack in the magneto distributor block. The most appropriate action is to:
Answer: Replace the distributor block before returning to service
A cracked distributor block can allow high-voltage leakage or cross-firing between electrodes and must be replaced per manufacturer's instructions before flight.
The purpose of the safety gap (or backup gap) in a magneto is to:
Answer: Provide an alternate discharge path if a spark plug lead is open-circuited
If a high-tension lead is broken or disconnected, the safety gap allows the voltage to discharge internally rather than damaging the coil insulation.
Spark plug gap erosion over time causes the ignition system to require:
Answer: Higher voltage to jump the wider gap, potentially causing misfires
As electrode material erodes, the gap widens and the required ionization voltage increases; if the magneto cannot supply it, the plug misfires.
What does a magneto timing light (buzz box) detect when connected to the P-lead terminal?
Answer: When the breaker points open, indicating the spark firing instant
The timing light illuminates or changes state the instant the breaker points open, allowing the technician to correlate point opening with a specific crankshaft degree mark.
In a low-tension ignition system, the high-voltage transformer is located:
Answer: At each spark plug, immediately adjacent to the cylinder head
Low-tension systems distribute low voltage from the magneto and use individual transformers at each plug to step up voltage, reducing harness insulation requirements.