The Tongan government says it will put the  troubled MA60 airliner back into service.

The aircraft has been grounded for several years.

A government press release said it intended to have the aircraft back in operations within six months.

The government has signed a memorandum of understanding with the MA60’s manufacturer following a visit to China.

An aviation expert who spoke to Kaniva news on the basis of anonymity said it could cost up to TP$8 million to fix the aircraft.

“The MA60 has a lot of maintenance issues to resolve before it flies again,” he said.

He said the longer an aircraft was grounded the more servicing it would need to make it serviceable.

This included the requirement for some certain parts of the aircraft to be overhauled or replaced, he said.

China gave the aircraft, which is based on a 1960s Soviet design, to Tonga in 2013. It started flying  domestically in August of that year.

However the New Zealand government issued a warning to travelers over safety concerns for the aircraft and called for the aircraft to be certified by an internationally recognised certification authority.

It also suspended NZ$5 million in aid to the kingdom.

The aircraft is not certified for use in the European Union or the United states.

The MA60 has been involved in 15 accidents since it was brought in to operation.

According to a report in the Wall Street Journal, of the 57 MA60s exported by January 2016, at least 26 were in storage after safety concerns, maintenance problems or performance issues and six others had been damaged beyond repair.