The VAR NR caution on the CAD and MAN pushbuttons for the VARTOMS Mode Selector illuminates in flight if the engines experience a torque split that exceeds what percent?

• A. 10%
• B. 15%
• C. 20%
• D. 25%

Answer: (B)

The key idea here is how the system detects an abnormal imbalance between the two engines when using a torque-balancing mode. The VARTOMS Mode Selector is designed to share torque between engines, but if one engine is producing noticeably more torque than the other, the difference—called a torque split—can affect controllability and indicate a fault. The VAR NR caution on the CAD and MAN pushbuttons lights up when that torque split exceeds 15%, signaling the crew that the imbalance is beyond the acceptable range for that mode. This threshold is chosen to avoid nuisance warnings from small, normal variations while still catching meaningful problems early so you can investigate engine health, verify readings, and decide on appropriate action. Other thresholds would either be too sensitive, causing frequent warnings, or too lenient, missing a potentially unsafe condition.