The military has stopped taking delivery of Korean-made helicopters once touted as the crown jewels of the domestic arms industry after they failed a safety test in the U.S.
About 50 of the KAI KUH-1 Surion helicopters have already been deployed warfare-ready.
The Surion failed flight safety tests in cold, wet conditions in Michigan between last October and March, according to data from the Defense Acquisition Program Administration published by Saenuri Party lawmaker Lee Chul-gyu.
The flight test was carried out at 5 to -30 degrees Celsius and found that more than the permissible level of 100 g of ice built up at the air inlet of the engine. If ice is sucked into the engine, the airfoil can break down and stall the engine, according to GE, the maker of the engine.
The Defense Ministry and the DAPA recently told Korea Aerospace Industries, the developer and maker of the chopper, to halt supply.
A KAI spokesman claimed the tests were conducted in extremely cold and wet conditions, which do not reflect Korea's dry and far less cold winters. "In Korea, ice normally forms in helicopters at an altitude of 600-900 m in early foggy winter in November and December and in early spring in February and March," an official with the Aviation Meteorological Office said.
Some 50 Surion helicopters already deployed at various military units will probably not be fully maneuverable in winter until the problem is addressed, and potential overseas buyers may think twice whether the chopper is right for them.
According to DAPA, seven components of the helicopter need to be improved to solve the problem. The air inlet and two other parts will have to be redesigned from scratch, which will take about two years.
The development of the Surion cost W1.3 trillion (US$1=W1,105). President Park Geun-hye went aboard a Surion in May 2013 when Korea's first indigenous utility helicopter was unveiled to the public.
KAI has made some 50 at a cost of W1 trillion and the military had planned to buy some 200 more for another W5 trillion by 2023. KAI hoped to sell about 300 of them abroad.
KAI says the Michigan tests were "an optional extra" to help with exports but the chopper can still be sold as is to Southeast Asia or the Middle East, where winters are warm and dry.
But Lee said the icing test is "a prerequisite" for deploying the choppers fully warfare-ready.
