SF 340B
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical
Flight Crew Diverted; Flight Crew Landed As Precaution; Flight Crew Landed in Emergency Condition
Aircraft
We departed and performed a flaps 15; 100% torque; ECS off; A power take off. On the initial climb out; I noted the RT engine ITT reach 965. At positive rate I put the gear up. At approximately 300-400ft AGL the LT engine began popping and the aircraft was yawing with the LT engine torque fluctuating to 40% and the LT engine over-temp light illuminating. The popping and yawing of the aircraft repeated 3-4 times. I [notified ATC] that I was going to [a nearby airport]. They told me to contact Approach. I then told First Officer (FO); 'my controls' and reduced the LT engine torque to 20-30%. The popping and yawing of the aircraft stopped. FO contacted Approach and told them we will be landing. I called for the gear down and lined up with [the runway]. We did not contact Tower for a landing clearance. I verified my landing configuration and preformed a stable approach and landing. On the descent; [the] Flight Attendant (FA) rang our call button and we did not respond while dealing with the [situation]. Upon landing I shut down both engines on the runway where we stopped. We had no indication of fire from our flight deck annunciators. I made an announcement to the passengers and then exited the flight deck to visually inspect the LT engine. [The] FA notified me that a passenger had seen fire coming from the LT engine. I saw no indication of smoke or fire upon visual inspection. As a precautionary measure; I told [the] FA to evacuate the passengers; then I returned to the flight deck to run the evacuation QRH with [the] FO. The crew assisted all passengers out the RT forward exit. The fire fighters determined there was no fire hazard with the aircraft. They also confirmed with the passengers that there were no injuries. It is my suggestion to not utilize aircraft with an engine on derivate power during the warmer summer months.
During climb out we noticed the RT engine temperature at 965 ITT at 100% torque. While watching and making corrections on the right power lever to avoid the RT engine from overheating; and about 400 feet we heard about 4 loud bangs on the LT engine; strong vibration and a pulling yaw; the torque oscillated between 40% to 80%; and the over temp light illuminated as well. The Captain transferred the controls; and reduced the power on the LT engine and the banging decreased. That's when we realized we had the two engines compromised.
SF340B flight crew reported high ITT on the right engine and vibration and low power output on the left engine after takeoff. They diverted to a nearby airport and landed safely.