The man in charge of drafting operational manuals at Darwin's Don Dale youth detention centre has spoken of his frustration at the sheer lack of standard procedures being followed there.

Former youth justice officer Leonard de Souza recounted to the Royal Commission into the Protection and Detention of Children in the Northern Territory how the manuals he wrote — both standard operational procedures, and emergency procedures — were "left on the shelf" by management.

He said that a change of management after 2009 resulted in "a downward spiral" of staff morale and day-to-day operational procedures.

Mr de Souza said prior to this time, he and other staff had successfully run many engagement programs for the children, and that the use of isolation cells had been limited and appropriate.

Don Dale became a place of chaos

Mr de Souza painted a picture of Don Dale as being a place that operated without standard procedures, and that it was a place of general chaos.

After he became an official staff trainer in 2011, Mr de Souza wrote two manuals — one for standard operating procedures, and also for emergency procedures.

He said neither manual seemed to have the backing of management.

Mr de Souza recalled an instance of giving a new youth justice officer a tour of the facility, when they encountered a shift supervisor on the floor.

He said the shift supervisor said to the new youth justice officer, "After Lenny [Mr de Souza] leaves, we'll show the real way to do it'."

Mr de Souza agreed when asked by counsel Peggy Dwyer that by 2013-2014, "rules didn't matter at Don Dale".

He said that he had envisioned the manuals becoming the standard "go-to" documents for all staff working at the centre.

"A youth justice officer can't say they didn't know [about what to do in a certain circumstance], because it's there in the manual, they'd been given a manual, and the requirement of working with young, vulnerable people is to ensure they actually know their operational requirements," Mr de Souza said.

Senior counsel assisting the inquiry Peter Morrissey SC asked Mr de Souza where, given that the manuals weren't prepared until 2014, youth justice officers turned to in order to find out what particular procedures were.

"Was it simply the discretion of the shift supervisor of the day?" Mr Morrissey asked. "Absolutely, and it was the same routine of doing their own thing on each shift, which really brought chaos to the centre."

No evacuation plans for detainees locked in cells

One concern Mr de Souza highlighted in his evidence to the royal commission was a lack of evacuation plans, namely in the event of a fire.

"With fire plans [management would] say 'oh there's an alarm going - don't move, it's all good'. But there was no evacuation procedures, no drills," Mr de Souza said.

Ms White asked whether, given the detainees were locked in their cells, there was a plan for who would manage keys in the event children needed to be evacuated.

Mr de Souza replied:

"The emphasis was on a senior being responsible, but there was nothing formally written. And if I was a new person, how would I actually know [what to do], like where a muster place would be?"

Mr de Souza said he had particular concerns about a wooden roof that was then in place in the maximum security unit, and that a fire had been put out there by a guard out of "sheer luck".

"It was really dangerous, absolutely," he said.