In a multiengine aircraft, which engine's failure would most adversely affect performance or handling qualities?

In a multiengine aircraft, which engine's failure would most adversely affect performance or handling qualities?

• A. Critical Engine
• B. Primary Engine
• C. Least-Used Engine
• D. Right Engine

Answer: (A)

When one engine quits in a multiengine airplane, the airplane tends to yaw toward the failed engine because thrust is lost on that side while the other engine continues to push the aircraft. The critical engine is simply the one whose failure would produce the greatest drop in performance and the most difficult handling. This is because its loss creates the largest yaw moment and the biggest reduction in climb and overall controllability, given how the remaining engine’s thrust interacts with the air and the aircraft’s geometry. Often, in conventional twins with typical propeller rotation, that engine is the left one, but the exact critical engine depends on the specific aircraft design and is stated in the airplane’s flight manual. The other terms listed don’t describe which engine’s loss has the most severe impact on handling, so they aren’t the correct concept here.

When one engine quits in a multiengine airplane, the airplane tends to yaw toward the failed engine because thrust is lost on that side while the other engine continues to push the aircraft. The critical engine is simply the one whose failure would produce the greatest drop in performance and the most difficult handling. This is because its loss creates the largest yaw moment and the biggest reduction in climb and overall controllability, given how the remaining engine’s thrust interacts with the air and the aircraft’s geometry. Often, in conventional twins with typical propeller rotation, that engine is the left one, but the exact critical engine depends on the specific aircraft design and is stated in the airplane’s flight manual. The other terms listed don’t describe which engine’s loss has the most severe impact on handling, so they aren’t the correct concept here.