"the fact
that there was no training method for effective communication in an
unexpected or abnormal situation and that the crew therefore had not
practised this contributed to the crew not being able to jointly identify
the problem in time"
The operator has to be the main culprit here, not having a training standard that at least addresses this BASIC CRM issue.
Any "normal" fault detection should at least be confirmed by 2 or more parameters, and cross referenced between the crew.
Both crew was relative "low experienced" guys, however in my opinion the operator does not seem to have had a sufficient high standard of training, leading to an event like this being allowed to happen. Basic CRM and Error fault management seems to have been completely lacking.