In its preliminary report, air crash investigators said voice recordings showed the pilot’s rate and volume of speech had “substantially lowered”.
The aircraft is thought to be the Coulson-operated N619SW, which has been in the state since mid-December after working previously in the US.
The United Firefighters Union aviation secretary Wes Garrett said the “in principle” agreement would also include boosting the number of airport firefighters.
Captain Ian McBeth’s widow said, "Those in the best position to determine if it was safe to send the plane up have let all of our families down and have a lot to answer for.”
The business’ global CEO, Wayne Coulson, also told Australian Aviation the loss of Captain Ian McBeth, first officer Paul Hudson and flight engineer Rick DeMorgan is still “deeply felt” by the organisation.
An ATSB report into the deaths of three American firefighters who died tackling the Black Summer blazes has highlighted the inadequate risk planning of operator Coulson and the NSW Rural Fire Service.