South Korea’s Surion helicopter fails test

South Korea’s Defence Ministry and the Defence Aquisition Programme Administration (DAPA) have suspended further deliveries of the domestically-made Surion KUH-1 helicopter to the Army after the aircraft failed a cold-weather test seven months ago. However the DAPA report was only revealed this week by a parliamentarian, a member of South Korea’s centre-right Saenuri Party.

Saurian KUH-1 in Alaska

Surion KUH-1 in Alaska


The twin-engine, utility, 8-tonne class helicopter, which transports up to 11 troops, was co-developed by Korea Aerospace Industries (KAI) and Airbus Helicopters in a 2006 US$1.36bn project to replace Seoul’s ageing fleet of UH-1Hs and 500MDs.

KAI has delivered 54 Surions to the Army since 2013 and is under contract to supply another 200 by 2023. Why then, one wonders, was this cold and wet weather test not undertaken before the aircraft was declared operational? The Surion was flown in temperatures of 5 to -30°C but more than 100 grammes of ice built up at the engine’s air inlet, a DAPA spokesman said, leading to a possibility that the engine could stall.

The test took place in northern Michigan, United States, between October 2015 and March this year, according to DAPA. “The Surion failed the test carried out to see the impact of ice generated during flight under humid and freezing conditions on the engine and several other components,” the DAPA spokesman said, adding that the helicopter had failed to satisfy 29 of the 101 requirements.

As for the Surions already with the Army, a KAI official said, “their flights and operations will be regulated due to safety concerns, particularly in areas or climates where the temperature falls to more than five degrees below zero coupled with a certain level of humidity.”

The Surions in a demo flight (photo credit: South Korean Defence Ministry)

The Surions in a demo flight (photo credit: South Korean Defence Ministry)


A somewhat embarrassed KAI says that even if the extremely cold and wet conditions of northern Michigan did not reflect South Korea’s dry and warmer winters, the company will improve the seven components that are creating the problem, including a complete redesign of the air inlet and two other parts. “Passing the test is essential to better exporting the Surion helicopter,” the official noted. Notwithstanding the failed test, Surion could be sold as is in Southeast Asia or the Middle East which do not suffer from cold, wet winters. KAI hopes to export about 300 Surions.

Meanwhile KAI will continue building the 90 Surions currently under construction at its manufacturing facility in Sacheon, 437km south of Seoul and will replace the failed parts with the updated ones later.

KAI is the prime contractor on the Surion with Airbus Helicopters providing technical assistance, and supplying the rotor mast, transmission, and autopilot sub-assemblies. Airbus Helicopters’ stake in the programme stood at 30% in the development phase and now stands at 20% in the production phase.

The state-run Korea Development Bank owns a controlling 19.02% stake in KAI, followed by the Export-Import Bank of Korea with 7.73% and the National Pension Service with 9.40%.