Supersonic drama: the story of South Korea’s new fighter jet


Fifth-generation fighter jets are the embodiment of the latest technological advancements in military technology. They are associated with concepts such as stealth, extreme flight performance, and advanced computer systems.

Another word sometimes associated with fifth-generation fighter jets is drama. Consider the US-made F-22 and F-35 which were accused of being too expensive. Meanwhile, the Russian Su-57 was often in the news, whether it was the countless delays and trouble with its engine to uncertainties about overseas orders. Even China’s FC-31 – despite its highly secretive development – has been known to encounter difficulties, spending years in limbo and re-emerging almost a decade after its first flight.

Recently, South Korea has been making headlines with its own fighter development program – the KF-X. The aircraft developed during the program has been christened the KF-21, and is currently awaiting its maiden flight. It is debatable whether the aircraft really is fifth-generation as it lacks some crucial new generation features, such as internal weapon bays and supercruise ability. However, there are some next-gen staples the KF-21 has in spades: stealthy design, advanced avionics, and a propensity to be much talked about. 

The Indonesian entry

Some of the stories were fairly commonplace: issues with funding, delays, and claims that the jet was too expensive. But the program marched on and, as of late 2021, the aircraft is nearing its first flight.

However, another well-publicized problem has dogged the program. 

Korean Aerospace Industries (KAI) was seeking foreign partners before the requirements for the KF-X were finalized. Countries with a history of buying South Korean aircraft were the main candidates and, of those, Turkey and Indonesia both expressed interest.

Turkey’s involvement did not materialize, so Indonesia was left as the sole partner for KAI. In 2010, an agreement was signed, under which Indonesia agreed to contribute up to 20% of development costs and receive 50 aircraft in return. As neither the costs of the development nor production deadlines were clear, the terms were subject to further discussion.

Between 2011 and 2014 the discussion could not take place because the program was stalling. KAI struggled to procure funding. Newly-elected South Korean president Park Geun-hye was against the project, and the program was postponed for 18 months during her tenure. 

It slowly restarted in 2015, and after the actual design of the aircraft was selected, the development team outlined the budget. It envisaged Indonesia contributing one-fifth of the jet’s 7.5 trillion won ($6.3 billion) development cost. PT Dirgantara Indonesia (PTDI) – Indonesia’s state-run aerospace manufacturer – would also closely collaborate with KAI, lending a part of its workforce to the project.

Falling out

For a while everything seemed to run smoothly. But then, cracks started to appear.

In November 2017, the Korean Defense Acquisition Program Administration (DAPA) announced that it had not received the promised monetary contribution from Indonesia – some 138.9 billion won ($124.5 million) was due for the development that year. Only a quarter of the sum was transferred.

In the wake of the announcement, South Korean MP and member of the National Assembly Defense Committee, Kim Jong-dae, said that with the Indonesian contribution gone, the entire project had a real chance of being cancelled. 

One of the reasons for that was obvious. Procuring the budget for the aircraft took five years and the program was constantly criticized as being too expensive. Increasing the South Korean contribution by 20% would have looked unattractive. But an even bigger problem was brewing backstage.

In 2016, a sprawling, multi-layered corruption scandal centered around the president Park Geun-hye was reported in South Korea. It involved espionage, conspiracies, and secret religious cults. Park was forced from office in mid-2017 and, and as she was a stark opponent of the KF-X project, it could have been a good omen for the new airplane.

It was not. Unrelated to the president’s impeachment, a host of other corruption scandals reverberated throughout the country, and Korean Aerospace Industries found itself in the middle of one. Autumn of 2017 saw the top management of KAI faced with a wave of prosecutions, arrests and even suicides. This did nothing to bolster Indonesia’s commitment to the aviation project. Was this the end?

As it turned out, Indonesia had been having its own doubts about the jet.

In September 2015, Indonesian Minister of Defense, Ryamizard Ryacudu, said that the development of the aircraft was unnecessary and the country should postpone paying for it. Nevertheless, in October of that year, PT Dirgantara Indonesia and KAI signed a deal regarding the payments. But it was clear that the Indonesian government was very much on the fence.

The entire program – to which Indonesia contributed only a minor part – was hanging in the balance.

Endless renegotiations

By early 2018, the problem had still not been resolved, and reports emerged that Indonesia was seriously reconsidering its involvement. It recalled 80 PTDI workers who had been stationed in South Korea, and hinted at a need to “renegotiate” its involvement.

“Frankly, the Indonesian delegation was restricted from accessing many part[s] of KF-X technologies and studies, particularly from the ones regarding the US,” one of those workers told Defence News in May 2018. This shed some light on yet another problem.

In 2016, South Korea, Indonesia and the United States had a series of trilateral meetings in regards to the transfer of some advanced technologies, reportedly related to the F-35 program. The negotiations did not go as well as expected as the US expressed doubts with Indonesia’s trustworthiness. Indonesia was not exactly committed to NATO and its allies and, as the KF-X program was running, it negotiated the purchase of some new Russian jets for its Air Force.

The problems seemed to pile on. A renegotiation was under way in which Indonesia tried to obtain better conditions, and South Korea tried to maintain the status quo. At the same time, South Korean officials continuously said that the development was on track.

Then, in October 2019, a mock-up of the KF-X was publicly displayed for the first time at the Seoul International Aerospace and Defense Exhibition. As the final look and characteristics of the jet were revealed, Indonesia was absent from the presentation. It had been more than two years since the renegotiation was “about to end”.

Throughout this whole period, Indonesia was still paying for the program, but not according to the schedule that had been agreed upon. In 2017 it paid one-fourth of the year’s sum, and in 2019 it paid 272.2 billion won ($230 million) of 301 billion won ($255 million) – still not the required sum.

Pandemic-ridden 2020 was the third year of renegotiations, and it was full of unconfirmed reports that Indonesia was about to leave the program as well as KAI’s claims that everything was fine. While PTDI engineers returned to work at KAI, the COVID-19 situation stretched Indonesia’s budget thin.

Light at the end of the tunnel

In mid-2021, KAI made the biggest public presentation of the jet yet. The first prototype was rolled out, the name of the aircraft was revealed and, most importantly, all of that was done in compliance with the development timeline announced back in 2017. 

In contrast with the mock-up reveal at Seoul International Aerospace and Defense Exhibition in 2019, Indonesia was not forgotten. Indonesian Defense Minister Prabowo Subianto was present at the roll-out. He praised the jet, the Indonesian-South Korean cooperation, and the work of KAI. 

Subianto’s statements about the new aircraft – which received the name KF-21 Borame in South Korea and the F-33 in Indonesia – were taken as confirmation that the two countries had found common ground. All seemed well.

However, there was no announcement about the end of renegotiations, its results, or the new conditions for Indonesia’s involvement. Even as the prototype was slowly being prepared for its maiden flight in 2022, Indonesia was continuing to pay for the development on its own terms. 

In October 2021, Kang Eun-ho, head of South Korea’s arms procurement agency DAPA, hinted that the roll-out was not the end of the KF-X story. 

“I am convinced that [talks over] the issue of the overdue payments will be concluded by November. We will finish it by then,” Eun-Ho said

Only time will tell.

UPDATE 08-11-2022, 14:00 (UTC +3) Since the publishing of this article, in December 2021, DAPA announced reaching a deal with Indonesia regarding the payments for the program. On July 19, 2022, the prototype of the KF-21 conducted its maiden flight.


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