SEOUL — A fatal crash of a South Korean Marine Corps helicopter is expected to deal a serious blow to the local helicopter maker’s export bids as well as domestic supply to the military and civilian buyers, experts and industry sources say.

On July 17, an MUH-1 Marineon, a variant of the South Korean Army’s KUH-1 Surion utility helicopter, crashed during a test flight at an airfield in the southeastern port city of Pohang, killing five of the six marines aboard. Closed-circuit video footage released by the Marine Corps shows the rotor blades fell apart shortly after takeoff. The rotorcraft caught on fire immediately after crashing.

The deadly accident occurred just six months after two units of the Surion’s amphibious assault variant were delivered to the Marine Corps, which was planning to procure 28 Marineon aircraft by 2023.

A military investigation committee involving experts from Airbus Helicopters, which had provided its SA 330 Puma design and related technologies to Surion manufacturer Korea Aerospace Industries, or KAI, has launched a probe into the cause of the accident. Meanwhile, some local experts are raising concerns about potential defects in the rotorcraft’s components, such as the main gearbox, and over possible design failures in the modification process of the rotor blades' folding system for the Marine variant.

“The footage clearly shows the rotor blade was destroying and being separated from the fuselage, indicating the possibility of mechanical defects,” Kim Dae-young, a research fellow of the Seoul-based think tank Korea Research Institute for National Strategy. “Without the possibility of maintenance failures, it’s highly possible that design and component defects could be blamed for the crash.”

Yang Uk, a member of the advisory committee for the government’s Defense Acquisition Program Administration, or DAPA, pointed to the possibility of malfunctions with the aircraft’s fuel system.

“A fuel system normally explodes when an aircraft crashed from a high altitude. But the Marine one fell just 10 meters above the ground and caught on fire, which doesn’t quite make sense to me,” Yang said.

Following the accident, the Army grounded about 90 Surion troop-carrying helicopters deployed in the field. The service is supposed to receive some 150 more Surions by 2023. Flights of Surion’s civilian derivatives operated by the police, forest service, and fire and rescue service were also suspended.

As a result, the accident could give foreign helicopter makers more chances to win contracts on civilian helicopters in the short term, according to Ahn Young-soo, a researcher at the state-funded Korea Institute for Industrial Economics and Trade.

“The Marineon crash will inevitably cause a setback in the domestic supply of Surion variants due to safety concerns,” Ahn said “In particular, Surion variants could be shunned in the civilian helicopter market, which has been dominated by foreign helicopter makers.”

KAI previously forecast that Surion variants would be able to replace about 80 foreign helicopters used by government agencies by 2030, reaping nearly $1.8 billion. Currently, government agencies operate about 100 helicopters, while about 100 corporate and private helicopters are flown in the country.

KAI has signed contracts to supply the Korean National Police Agency with eight patrol variants of the Surion; the Korea Forest Service with one firefighting version; the Fire Safety Headquarters of Jeju Special Self-Governing Province with one firefighting and rescue version; and the Coast Guard with two maritime patrol derivatives.

Some of the agencies, however, are having second thoughts about additional orders of Surion variants.

“The Surion patrol helicopter has conducted successful missions so far, but we’re not sure if we can order more in the current state,” said an air operations management official at the Korean National Police Agency, speaking on condition of anonymity. “We’re closely watching the results of the investigation into the Marineon crash.”

Even before the Marineon accident, many fire and rescue departments across the country were hesitant to introduce Surion variants, citing the lack of an airworthiness certificate for safe flights. The Surion was originally built for domestic military operations, and so it only received a certificate of airworthiness from the DAPA. But some of the fire and rescue headquarters issued requirements including a certificate of airworthiness from the International Civilian Aviation Organization, or at least one from the local transportation ministry.

Against that backdrop, both the fire and disaster headquarters in Seoul and Busan purchased AgustaWestland AW189 and AW139 medium-lift helicopters, respectively, in 2016. Last year, the National 119 Rescue Headquarters signed a contract with Airbus Helicopters to buy two H225 helicopters.

“The first priority is safety. That’s the bottom line,” noted Kim Kyung-ho, a deputy director of the National 119 Rescue Headquarters in Seoul. “We didn’t intend to deny a local helicopter nor give a favor to a foreign helicopter. As an agency tasked with rescue operations, we just need helicopters guaranteed for safety both locally and internationally.”

Surion’s export bids remains unclear.

Following a visit by President of the Philippines Rodrigo Duterte to Seoul last month, the Philippines' Department of National Defense looked into buying a score of Surion helicopters as an alternative to a botched deal to procure 16 Bell EPI helicopters from Canada. KAI President Kim Jo-won had told a parliamentary forum on June 28 that “the Surion deal worth $220 million is in the final stage.”

Following the fatal crash, however, the Manila government halted discussions about the Surion purchase, according to DAPA and KAI officials.

“The Philippines government requested us to provide information about the cause of the accident,” a KAI official said. “Discussions about the Surion export are expected to resume after the results of [the] investigation [are] release[d].”

Modeled after the SA 330 Puma, the Surion was built in technical assistance from Airbus Helicopters, formerly known as Eurocopter, under a 2006 deal valued at $1.2 billion. The 8.7-metric-ton rotorcraft can accommodate two pilots, two gunners and nine fully armed troops. Without arms and equipment, it can handle 16 troops. The helicopter can fly at a cruise speed of 279 kph.

South Korea chose Airbus Helicopters for a new light helicopter development project in 2015. Under the $1.4 billion agreement, South Korea will develop a light-weight helicopter with a gross weight of about 4.5 metric tons for both civil and military purposes.

The helicopter will be designed on the basis of the Airbus H155, a wide-cabin derivative of the AS365 Dauphin of the 1970s. The civilian variant is to be developed by 2020 and the military version by 2022, with the aim of supplying about 400 units domestically and exporting some 600 units overseas.