Spare parts for the Government jet were sold for €53,000, eight times lower than their estimated value, according to the report of the Comptroller and Auditor General.

And the jet itself was sold for €350,000 less than its estimated worth.

The 14-seater Gulfstream IV jet, which had been in service since 1992, was sold in January 2015, for €400,000.

The C & AG report for 2015 said the decision to sell it was made because of escalating repair costs.

A memo to government said beyond 2018/2019, retention of the aircraft would be unsustainable as it would need both engines overhauled at a cost of €2.5 million. Estimated costs for maintenance in 2014 would be €1.34 million.

The C & AG report said the Department of Defence did not carry out a formal analysis of “remaining life costs” for the jet. Such an analysis would have estimated future economic costs and benefits.

The General Officer Commanding the Air Corp recommended the aircraft should be repaired, in August 2014. And the deputy chief of staff also recommended the aircraft be returned to service.

But the then minister for defence, Simon Coveney, was told the aircraft was stripped down and blocking a busy production line at its manufacturer’s in the US, since July, and any further delay would incur substantial costs.

On August 15th, 2014, the minister directed no more work should be carried out and the jet should be sold for salvage.

No tender process was carried out to dispose of the jet and it was sold to US company Journey Aviation, for €418,000 in January 2015.

Spare parts for the plane, costing €1.4 million when purchased, and valued at €405,000, were sold to the same company in February 2015 for €53,000.

The C&AG recommended the department ensure cash flow analysis is carried out for all major items of equipment and decisions about selling or retaining such equipment should be made based on such an assessment.

In response, the department said there were “particular and extenuating circumstances” which were “not conducive” to carrying out a formal analysis. An informal analysis was carried out, it said, and the “most prudent decision was made”.