Been a long time since this happened but I thought I might resurrect the thread with a report.
No evidence of engine malfunction or anything wrong with the aircraft. The takeoff roll was much longer than normal and td after rotating at a higher than normal speed and achieving a reasonable initial climb rate, the rate of climb decreased. There seemed to be some sort of power asymmetry as well. Yet, according to the report......."Maximum rpm was not selected for departure but it was unlikely that this explained the aircraft’s poor performance on the runway or in the air. The pilot insisted that he had set torque to the takeoff limit."
Sure would have been nice to have some sort of recording of power lever position as it would be nice to have actual confirmation that they were really at full power. No mention in the report on whether the friction knobs were found to be tight or loose.
Beech_90_N46BM_02-12.pdf (publishing.service.gov.uk)