What is the TOGA ITT limit for five minutes?

• A. 964C
• B. 948C
• C. 960C
• D. 950C

Answer: (B)

The key idea is understanding what the five-minute TOGA ITT limit represents: it’s the maximum turbine inlet temperature you may allow while operating at TOGA thrust for up to five minutes, to protect the engine from overheating during takeoff and GA.

For the CRJ-550 in question, that five-minute TOGA ITT limit is 948C. This specific value is what the aircraft’s limits specify, reflecting the engine and configuration used on this airplane. Keeping ITT at or below 948C during the TOGA window ensures the turbine components aren’t overstressed while providing the needed takeoff thrust.

The other numbers aren’t the documented five-minute TOGA limit for this airplane; they would pertain to different limits (perhaps other durations or engine configurations) and could lead to operating outside the approved envelope if used as the five-minute TOGA cap.