Which is a max transient engine parameter?

Which is a max transient engine parameter?

• A. 106% N1
• B. AEO 5 min
• C. OEI 10 min
• D. 5 mins

Answer: (A)

During rapid throttle changes, engines have a transient overspeed limit to allow quick acceleration without risking damage. The key value here is the maximum N1 the engine may briefly reach in a transient, expressed as a percentage of its saturated speed. A value around 106% N1 is the common transient limit, giving enough margin for performance while protecting the compressor and turbine from excessive stress. The other items describe duration limits for engine-out conditions (how long you can operate with all engines or with one engine inoperative) or are just a plain time value, not a speed or parameter. They don’t define how fast the engine is allowed to run during a transient, so they don’t answer the question about a max transient parameter. Therefore, 106% N1 is the best choice.

During rapid throttle changes, engines have a transient overspeed limit to allow quick acceleration without risking damage. The key value here is the maximum N1 the engine may briefly reach in a transient, expressed as a percentage of its saturated speed. A value around 106% N1 is the common transient limit, giving enough margin for performance while protecting the compressor and turbine from excessive stress.

The other items describe duration limits for engine-out conditions (how long you can operate with all engines or with one engine inoperative) or are just a plain time value, not a speed or parameter. They don’t define how fast the engine is allowed to run during a transient, so they don’t answer the question about a max transient parameter. Therefore, 106% N1 is the best choice.