South Korea's state audit agency said Sunday that the country's transport utility helicopters have various defects including flight stability and requested that the prosecution probe  the arms procurement chief on charges of breach of trust.

The Board of Audit and Inspection said that South Korea-born Surion helicopters are not airworthy as they lack lightning protection and anti-icing capability, while failing to receive proper engine certification. It even reported that the homegrown chopper, also called the KUH-1, has a water leakage problem.

The BAI said it requested a prosecution probe into Chang Myoung-jin, chief of the Defense Acquisition Program Administration, and other two officials for breach of trust. Chang determined in December 2016 that the Surions were ready to operate even though they failed to meet airworthiness qualifications.

The BAI said it gave a "warning" to Chang and asked the other two officials, including the head of the Korean Helicopter Program, to be demoted.

The audit agency also ordered Chang to halt delivery of the Surions until their problems are fixed and the DAPA to file damage claims against Korea Aerospace Industries Ltd. It also asked the South Korean army's chief of staff to consult with Chang to come up with safety management measures on the Surions. 

South Korea invested 1.29 trillion won from June 2006 for KAI, the country's sole aircraft manufacturer, to develop the Surion and the project was completed in July 2012 after it was approved for combat-use. Since then, South Korean military has been using 60 Surions in the field.

However, various accidents took place after the chopper went into operation. In January and February 2015, two Surion helicopters made an emergency landing following an engine failure, while another Surion chopper crash landed due to same problem.

The BAI said the 2015 incidents are related to Surion's lack of anti-icing capability and the officials negligence to fix the problem.

From October 2015 to March 2016, the DAPA conducted a set of tests in Michigan regarding the Surion's operation in humid and freezing conditions, but the chopper failed to meet 29 of 101 standards. The DAPA in August 2016 decided not to deliver the Surion to the South Korean army, but after the KAI announced in October that it will fix the problem until June 2018, the arms procurement agency decided to resume delivery of the helicopter even though no measures were taken to correct the icing defect.

The BAI also ordered the South Korean army's chief of staff to request compensation from KAI and the Surion's enginemaker Hanwha Techwin Co. for the chopper's crash in 2015 and get a free engine replacement from the two companies.

State prosecutors on Friday, meanwhile raided the offices of KAI on allegations of corruption in a set of major defense projects. (Yonhap)