In regards to the ECS turned on resulting in a higher temperature on one engine it is clear that only one of the ECS air valves is working correctly. These are of a design that wears and has poor sealing surfaces. We check them every 300 hours for correct sealing and have a test fitting which regulated air pressure is applied and the valve actuated to ensure correct function.
As for the pitch up, It is reasonably unique to BK117s.
When the BK117 is: High, heavy and apporaching VNE the design of the rotor system (rigid) and profile of the aircraft (long, large surface area belly) become factors in causing pitch ups.
To avoid this condition it is advised to fly at a a speed below the VNE markings for that altitude. We have had several cases in Africa where the autopilots engaged and a wind change or turbulence will cause a rapid pitch up which the autopilot can not rectify. The Autopilot was deisgned more for the BK117 at lower weights and the duplex pitch actuator does not have the authority to overcome such rapid pitch changes uninitiated by the pilot.
If the aircraft control rigging is carried out correctly and the aircraft flown IAW the VNE limitations the chance of pitch ups is greatly diminished! The maximum torque check for the collective overide spring to be reached is a good indicator to ensure the rotor system is not overpitched which exacerbates the pitch up problem. This requires correct flight control rigging and engine torque calibration.