TGT limiting is not available during which phase of operation?

TGT limiting is not available during which phase of operation?

• A. While in lockout
• B. Start up
• C. In flight
• D. Shut down

Answer: (B)

TGT limiting is a protective feature that uses turbine gas temperature readings to trim fuel and keep the engine within safe temperature limits during operation. It isn’t available during the start-up phase because the engine is in a controlled spool-up with the starter and igniters, and the FADEC/TGT system isn’t yet in a state to actively regulate TGT. The focus during start-up is to get the engine spinning and stabilized, after which ignition is established and the limiter can take over to protect the engine during normal operation and power changes. So, the phase where TGT limiting isn’t available is start-up.

TGT limiting is a protective feature that uses turbine gas temperature readings to trim fuel and keep the engine within safe temperature limits during operation. It isn’t available during the start-up phase because the engine is in a controlled spool-up with the starter and igniters, and the FADEC/TGT system isn’t yet in a state to actively regulate TGT. The focus during start-up is to get the engine spinning and stabilized, after which ignition is established and the limiter can take over to protect the engine during normal operation and power changes. So, the phase where TGT limiting isn’t available is start-up.