This had not been picked up in the investigation because it was not shown on maintenance sheets.
She queried where Mr Kershaw's plane was in relation to an aircraft being flown by his instructor working off the same air strip at the time.
Former Civil Aviation Authority inspector Tom McCready, said going by the Authority's information a stall led the aircraft to nose dive.
Mr Kershaw's last actions had been to inquire where the instructor was, something the Authority's report hadn't expanded on.
"The pilot was clearly concerned about his position in relation to the instructor's aircraft, otherwise he wouldn't have asked seconds before stalling," Mr McCready said.
He queried whether GPS tracking units had been fitted to both aircraft and raised the issue of pilot fatigue.
"Commercial pilots have flight and duty times, agricultural pilots don't," he told the court.
He said the report was not the way he would have written it, but that didn't mean it was wrong.
The crash scene investigator, Steven Walker, said he spent about an hour talking with Ms Mainland.
He confirmed there hadn't been GPS tracking systems operating in either plane and while it hadn't been possible to say exactly what caused the accident; some anomalies had been identified in Mr Kershaw's training.
Reserving his decision, Dr Bain noted that while a pilot may be trained by an experienced pilot that person may not necessarily be a "top dollar" instructor.
"And I do think ... that there should be more practice given to the best way of getting out of stalling at height with weight on board [such as a fertiliser load]."
Outside court Ms Mainland said she did not feel her partner had been fairly treated until the inquest. "But I am not pointing the finger at anyone," she said.
