After re-reading the report, I still have the opinion that the performance of the engine has not been sufficiently examined. My thoughts are based on information published in the report and other evidence. The other evidence is that similar Avon engines have suffered from power loss that was subsequently unexplained. Also, the video evidence of a considerable, possibly fluid, trail from the Fuselage of the accident aircraft seconds before the final manoeuvre is not mentioned at all.
Lastly, the report states:
"The engine manufacturer’s analysis of JPT and engine speed, derived from
the cockpit action camera recordings, revealed no anomalies during takeoff
and transit steady state conditions. There was insufficient data to verify engine performance during the dynamic manoeuvres".
This is wishy-washy. The Avon engine performance can be precisely calculated from the RPM and JPT values that the report states are recorded.
IMO, the following analysis should be possible: A precise assessment of the engine acceleration and thrust output on the take-off, compared to design performance. An accurate assessment and comparison of the percentage thrust achieved during the pull-up where 100% would be normally used.
My impression from the published illustration of varying engine performance parameters in the final manoeuvre is that, they might reflect the "throttle-pumping" actions of a pilot trying to get a full engine response. Of course, if the engine was only selected to partial throttle settings the achieved performance would be reduced but, it is possible that problems in fuel supply or engine control systems would simply prevent the achievement of full power.
The detailed component strip report lists some deficiencies in the engine fuel system, what I fail to read is some correlation between the deficiencies and the possibility that the engine could have underperformed in thrust levels or, perhaps more importantly, reliable throttle response?