ASA Powerplant Mechanic Practice Test

Using plugs or caps on the ends of disconnected lines is essential to keep contaminants, moisture, and debris out of the system and to maintain a proper seal under aircraft operating conditions. They’re designed specifically for this purpose and are rated for the fluids, pressures, and vibration the system will experience. Tape cannot provide a reliable seal and can fail in several ways: it may deteriorate with fuels or solvents, shed fibers or adhesive, loosen with vibration or temperature changes, or obscure leaks by masking them. This could lead to contamination, corrosion, or unnoticed leaks. By using the correct plugs or caps, you maintain system integrity and reduce the risk of foreign object intrusion or fluid leakage.