FAA Aviation Mechanic Powerplant (AMP)Reciprocating EnginesEasy
On a horizontally opposed four-cylinder engine viewed from the rear (accessory case), cylinder numbering follows standard convention. Where is cylinder number 1 located?
- ARight front
- BLeft front
- CLeft rear
- DRight rear
Show answer & explanationAnswer & explanation
Correct answer: A. Right front
On most horizontally opposed engines, cylinder numbering starts with the right front cylinder as number 1 when viewed from the rear (accessory case end), with odd numbers on the right bank and even numbers on the left bank.
Why the other options are wrong
- B. Left front is an even-numbered cylinder, not the starting cylinder.
- C. Left rear is typically the last even-numbered cylinder, not number 1.
- D. Right rear is an odd-numbered cylinder further back, not number 1.
Cylinder Numbering Convention
Standard method of identifying cylinders on horizontally opposed engines, viewed from the rear, with odd numbers on the right bank starting at the front and even numbers on the left bank.
- Cylinder 1 is the right front cylinder viewed from rear
- Odd numbers are on the right bank, even on the left
- Numbering is used to reference firing order and timing
Memory trick: Right side, Rear view, cylinder 1 is up front on the Right