It was only a “small” plane crash when a Pel-Air Westwind jet with six people on board ditched into the sea near Norfolk Island on November 18, 2009.

No one died, although a nurse on board the flight was seriously injured. The plane was on its way from Apia to Melbourne and had reached its intended refueling stop at Norfolk Island when it discovered the weather advice it had received was wrong. The plane was unable to land, and it had no reserves to reach an alternative destination.

Operator Pel-Air was a mess. It grounded its surviving Westwinds voluntarily after the crash. Its deputy chairman, former Coalition aviation minister John Sharp, even gave a media interview in which he admitted there “was no plan B” for the flight. The operator didn’t even have a written oceanic fueling policy. It was an appalling state of affairs, all seemingly brushed under the carpet by two safety authorities and a federal department, which concluded — despite evidence to the contrary — that the crash was entirely the fault of the pilot.

Ripples from the crash have since widened and amplified to slam into the air crash investigator, Australian Transport Safety Bureau chief commissioner Martin Dolan, and Infrastructure and Regional Affairs secretary Mike Mrdak. Former aviation minister Anthony Albanese, who did nothing about the situation, is left looking like a fool.

The ATSB report and the agency itself have been roundly criticised for avoiding responsibility. In response to the criticism, Dolan devised a “masterstroke”: he invited the Transport Safety Board of Canada to do a peer review of the ATSB.

The strategy seems to have been that a tame review of its processes and methodologies would end the ridicule it had attracted for blaming everything on the pilot. But sometimes your friends don’t give you the answers you want.

The review, which was handed down this week, was anything but tame. It slices to the bone when it comes to the failures of the ATSB to properly manage what was a long, acrimonious, bitterly contested internal investigative process that ignored or failed to collect vital information.

It shows how the ATSB crash inquiry was conducted in a state of confusion over the parallel actions of regulator CASA, which as an earlier Senate committee was to discover, hid a damaging internal audit that found that had CASA ever done its job in overseeing operator Pel-Air, the accident might not have happened.

There is enough in the TSBC report to have the chief commissioner of the ATSB removed forthwith. For such an important inquiry to be mismanaged for so long under his watch is inexcusable.

In a statement to Parliament on Wednesday the Deputy PM and minister responsible for aviation, Warren Truss, called on the ATSB to take a fresh look at the crash. That was a direction, not a suggestion.

But there is more to this than meets the eye. Since May, Truss had been led to believe, and accordingly advised the aviation media, that the TSBC review was imminent.

Well, it was. But it was constantly delayed by the resistance of the ATSB and, it seems, the Infrastructure Department to the content and tone of the supposedly friendly and collegiate Canadian report.

While this farcical stalemate was in play the department had also written an official response to criticisms made of the ATSB’s Pel-Air report by a Senate committee. The response said there was no value in revisiting the findings or retrieving the flight recorder from the sea floor near Norfolk Island, something the Australian investigator had resisted on the dubious grounds of cost.

Truss repudiated the advice from the Infrastructure Department by calling for the “fresh look”.

All the political and administrative capital invested by Infrastructure, the ATSB, and under earlier management, CASA, in thwarting a proper, thorough and fearless inquiry into the Pel-Air crash came undone.

The entire direction of the earlier Senate inquiry had been to test the integrity and procedural correctness of the ATSB and CASA in relation to the Pel-Air crash, and the Hansard of the proceedings includes references to covering up the regulator’s failings, avoiding operator scrutiny, and the determined pursuit of the pilot as scapegoat by CASA with the help of the safety authority.

That integrity was found wanting. The Canadian report supports the view that efforts to get to the truth of the matter were compromised by CASA’s determination to avoid the exposure of its failings by bending the ATSB to its will.

The Pel-Air scandal is an important reminder to the mandarins that there are times when the executive branch can (and should) prevail over the administrative branch.