maintenance safety requirment piston engines Flashcards
What is the primary advantage of a magneto ignition system in aircraft engines?
The primary advantage of a magneto ignition system is its simplicity and the fact that if one magneto fails, it won’t cause a catastrophic engine failure as the engine can continue to operate on the remaining magneto.
What is a magneto drop test, and when is it performed?
A magneto drop test is performed as part of the before-take-off checklist and post-maintenance. It involves running the engine at a specific speed and cycling through each magneto position (left, right, both) to check for proper disconnection when grounded and to observe acceptable rpm drops.
What happens to engine performance if one magneto fails during flight?
If one magneto fails during flight, the engine will produce slightly less power, but it will continue to operate on the remaining magneto. However, the engine will be 100% dependent on the functioning magneto.
Why is a magneto drop test critical for safe flight operations?
A magneto drop test is critical because it ensures that both magnetos are functioning properly and within acceptable limits. Exceeding the specified rpm drop limits could indicate a malfunction, necessitating maintenance before flight.
What are the typical rpm limits during a magneto drop test?
Aircraft manufacturers specify acceptable limits for rpm drop during a magneto drop test. If these limits are exceeded, the flight should not continue until the issue is resolved, which may involve retiming the magnetos according to the Aircraft Maintenance Manual (AMM).
What voltage levels are typically involved in the high-tension (HT) part of the magneto ignition system?
The voltage in the high-tension part of the magneto ignition system is usually in excess of 10,000 volts and can exceed 25,000 volts, making it potentially lethal.
Why is it critical to ensure the ignition system is safe before working on or around the engine?
It is critical to ensure the ignition system is safe because the high voltage in the magneto system can be lethal. Making the system safe prevents accidental engine firing or electric shock during maintenance.
What are the two stages involved in making the ignition system safe before maintenance?
The two stages involved in making the ignition system safe are turning the ignition switch to OFF, which grounds the primary winding, and turning the fuel switches to OFF, preventing the engine from starting even if the ignition switch fails.
What additional safety measure is recommended by some manufacturers when making the ignition system safe?
Some manufacturers recommend isolating the primary lead on the distributor cap as an additional precaution, in addition to turning the ignition switch OFF and the fuel switches OFF.
Why must a warning sign be placed over the ignition switch during maintenance?
A warning sign must be placed over the ignition switch to alert others that the engine/ignition system is being worked on, preventing accidental engine start during maintenance.
What is the purpose of turning the fuel switches to OFF during engine maintenance?
Turning the fuel switches to OFF ensures that the engine does not fire up in the event of a fault in the ignition switch while the engine is being worked on.
What precaution is recommended by certain manufacturers to eliminate engine compression during maintenance?
Certain manufacturers recommend removing one spark plug from each cylinder to eliminate any compression, further ensuring that the engine cannot start accidentally during maintenance.
