Free A&P Reciprocating Engine Overhaul Questions and Answers — Questions and Answers
Question 1: During a major overhaul of a reciprocating engine, a crankshaft runout check is performed. What is the primary purpose of this inspection?
- To measure the wear on the main bearing journals.
- To ensure the crankshaft is straight and not bent or warped. (Correct answer)
- To verify the correct dynamic balance of the crankshaft.
- To check for cracks in the propeller flange.
Correct answer: To ensure the crankshaft is straight and not bent or warped.
Crankshaft runout inspection is performed to detect any bending or warping along the crankshaft's axis of rotation. A dial indicator is used to measure any deviation as the crank is rotated. Excessive runout indicates a bent crankshaft, which must be straightened or replaced.
Question 2: A technician is reconditioning a set of cylinders during a top overhaul. The process of creating a specific cross-hatch pattern on the cylinder walls is known as:
- Lapping
- Glazing
- Honing (Correct answer)
- Reaming
Correct answer: Honing
Honing is the process of using abrasive stones to create a specific cross-hatch pattern on the cylinder wall. This pattern is crucial for proper piston ring seating and for retaining a film of oil to lubricate the rings.
Question 3: Which of the following statements is true regarding the installation of piston rings on a piston during a reciprocating engine overhaul?
- Ring gaps should always be aligned to minimize cylinder wear.
- The oil control ring is typically installed last, after the compression rings.
- Ring gaps should be staggered around the piston to prevent excessive blow-by. (Correct answer)
- All piston rings are symmetrical and can be installed in any direction.
Correct answer: Ring gaps should be staggered around the piston to prevent excessive blow-by.
Piston ring gaps are staggered (e.g., 120 or 180 degrees apart) to create a longer path for combustion gases to travel, thus minimizing blow-by and improving compression. Aligning the gaps would create a direct path for gas leakage.
Question 4: A mechanic is performing a major overhaul on a reciprocating engine. According to FAA guidelines and standard industry practice, what does this procedure entail?
- Inspection and repair of cylinders and pistons only, without splitting the crankcase.
- Complete disassembly, inspection, repair as necessary, reassembly, and testing of the entire engine to specified limits. (Correct answer)
- Replacement of all bearings and seals, with a visual inspection of other components.
- A thorough cleaning and pressure test of the engine without disassembly.
Correct answer: Complete disassembly, inspection, repair as necessary, reassembly, and testing of the entire engine to specified limits.
A major overhaul consists of the complete disassembly of an engine. The components are then inspected, repaired as necessary, reassembled, tested, and approved for return to service within the fits and limits specified by the manufacturer's overhaul data.
Question 5: After reassembling a reciprocating engine, a technician must secure numerous fasteners, such as connecting rod bolts and crankcase through-bolts. What is the primary purpose of using safety wire on these critical fasteners?
- To provide a secondary method of applying torque to the fastener.
- To act as a positive locking device to prevent loosening from vibration. (Correct answer)
- To indicate if a fastener has been previously tampered with.
- To ground the components electrically and prevent static buildup.
Correct answer: To act as a positive locking device to prevent loosening from vibration.
Safety wire is a positive locking device used to prevent fasteners from loosening due to vibration and other forces. It is installed in such a way that it applies a tightening force if the fastener begins to loosen.
Question 6: When installing new piston rings, the technician notices a small dot or the word 'TOP' on the side of a compression ring. What is the significance of this marking?
- It indicates the position where the ring gap should be placed.
- It marks the side of the ring that must face the top of the piston. (Correct answer)
- It is a manufacturer's inspection stamp and has no installation significance.
- It designates the ring as being for an intake-stroke compression cycle.
Correct answer: It marks the side of the ring that must face the top of the piston.
Markings such as a dot or 'TOP' indicate the side of the ring that must be installed facing the crown (top) of the piston. Many compression rings have a specific cross-sectional shape (e.g., beveled or tapered) that requires correct orientation to function properly for sealing and oil control.
Free A&P Reciprocating Engine Overhaul Questions and Answers
During a major overhaul of a reciprocating engine, a crankshaft runout check is performed.
What is the primary purpose of this inspection?