Tauranga airline Sunair remains grounded after a CAA official has resigned over the issues.

Northland politician Shane Jones is accusing the authority of 'stitching up” the airline.

Sunair was grounded for the second time on September 8. The Civil Aviation Authority suspended the Air Operator Certificate of Sunair Aviation Ltd, and also suspended the Certificate of Airworthiness for the Sunair fleet of aircraft.

A CAA spokesperson says it was initially for 10 days, but on Friday September 22, Sunair owner Daniel Power says they have heard nothing from CAA.

Northland resident and NZ First's Shane Jones says the grounding of Sunair is related to the resignation of CAA deputy director chairman Peter Griffiths, who resigned last week after passing on information regarding the suspension of Sunair to Great Barrier Island-based Barrier Air, which he owns 25 per cent of.

'I'm astounded at the Cynical Aviation Authority, that they have been allowed to get away with this stunt at a time when they should be working with this provincially important operator,” says Shane.

'They have taken a nut cracker approach. The fact that the deputy chairman has had to resign only further strengthens my belief that the chairman should have gone as well.

'It's been a gross collapse in governance. You need to bear in mind that the CAA have form in conflict of interest. They were investigated a number of years ago and found to be wanting.

'Their conduct towards Sunair I think is reprehensible. Sunair are valuable contributors to our tourism and our economy up in the north and also they have held an important contract in relation to our DHB.

'All these things are extremely important to us.”

CAA chairman Nigel Gould confirmed on Stuff that Griffiths acted before the latest suspension was in place, in the press release acknowledging the error.

'…When he initiated the contact with Barrier Air he did not realise that the suspension was not yet in place," says the CAA.

"It should be acknowledged that Peter's intent was to offer Barrier Air assistance to Sunair in order to minimise the adverse effect on its customers.

"Despite that good intent, Peter freely admits to an error of judgement and has submitted his resignation from the board."

The CAA says the decision to ground Sunair is the result of an audit of Sunair records which found a number of anomalies and omissions in maintenance records.

"These findings created a reasonable doubt about the airworthiness of the aircraft operated by Sunair and the Operator's maintenance control and the quality assurance systems intended to ensure their airworthiness," says an earlier CAA statement.

Daniel Power says the airline's last audit was a year ago, and on maintenance practices it was found to be excellent.

'And now we find for reasons that we don't fully understand, they now have concerns,” says Daniel.

'And in the last 12 months our maintenance practices and procedures have not changed.”

The airline was previously grounded by the CAA on December 6, 2016 over concerns about the airline's management structure.

The CAA became concerned the company's senior team was too small for the size of the business. That issue was successfully resolved and Sunair returned to the skies on December 16 2016.

When contacted for comment, the CAA released the following statement to SunLive.

When asked why it was necessary to suspend Sunair's Air Operator Certificate and the Certificate of Airworthiness for its fleet when Sunair had reported the issues under CAR Part 12 and they were being deal with.

The CAA reply is: "The decision to suspend Sunair resulted from an audit of Sunair maintenance records, conducted as a component of a recent change of their Maintenance Controller.

"The findings of this audit highlighted a number of anomalies and omissions in maintenance records that called into question the reliance that could be placed upon the operator's control and conduct of aircraft maintenance.

"These findings created a reasonable doubt about the airworthiness of the aircraft operated by Sunair and the Operator's maintenance control and the quality assurance systems intended to ensure their airworthiness.

"For this reason, the Director of Civil Aviation suspended the Sunair Air Operators Certificate, along with the Certificates of Airworthiness of its aircraft. (See section 17 of the Civil Aviation Act.) Sunair has the right to appeal these decisions to the District Court in accordance with section 66 of the Civil Aviation Act."

When asked if CAA considers it acceptable practice that a senior member of its board has acquired shareholdings in two air transport operators while he is the role, and when he is in the position of being privy to commercially sensitive information, CAA's reply is:

"By way of context, it is important to highlight that the Board is not involved in regulatory decision-making.

"This is done by the Director of Civil Aviation utilising powers that are independent of the Board. Having established that important fact, while acknowledging the obvious risks of having people with sector knowledge or involvement on the Board, there are also advantages to be gained from at least some of those providing governance of the CAA being familiar with the sector it regulates.

"Section 72A(5) of the Civil Aviation Act recognises this fact when it requires the Minister of Transport to consult with aviation industry bodies on the appointment of two of the CAA Board members.

"On balance, providing that conflicts of interest are managed correctly and Board members do not act on information held then the benefits of having some sector knowledge/involvement on the Board outweighs the risks."

CAA's answer to the question why it was necessary to suspend Whitianga operator FlyStark's operations for three months from May to July 2017 over an incident of superficial damage to one of its aircraft's wings, CAA replies:

"The aircraft in question was a Gippsland GA-8. Wingtip damage requires a maintenance inspection before the next flight, yet FlyStark flew. The maintenance manual for that aircraft requires that any damage to the outboard wing area, regardless of how minor it may appear, must be inspected by a maintenance engineer before the next flight (see section 17 of the Civil Aviation Act).

"For this reason The Director of Civil Aviation decided to suspend the aircraft certificate of airworthiness until such time as an inspection had been completed and to suspend the Air Operator's Certificate while the root causes were being investigated.

"Although this CAA investigation was completed within a couple of weeks, FlyStark management elected to extend their operational suspension until they were fully satisfied that they were ready to recommence safe air transport operations."