(An opinion piece written in response to the planned co-development of KT-1B Wong Bee by Indonesian State-owned aircraft manufacturer PT Dirgantara Indonesia (PTDI) after the Korean Aerospace Industries (KAI) has decided not to continue production of the military training aircraft itself)

The proposed partnership between Indonesian State-owned aircraft manufacturer PT Dirgantara Indonesia (PTDI) and Korea Aerospace Industries (KAI) to co-develop and produce a new trainer aircraft should not be viewed merely as a symbolic collaboration.

It will only make sense if it serves three strategic purposes: First, to strengthen Indonesia’s aerospace self-reliance through measurable technology transfer; second, to secure access to regional and global markets that are otherwise difficult to penetrate alone; and third, to mitigate the high risks of a long-cycle aircraft program, from design and certification to financing and after-sales support.

If structured as a genuine co-development or co-production venture, the partnership could allow Indonesia to accelerate its design and manufacturing capabilities, while KAI contributes its established certification track record, global supply chain, and export network.

The final goal should not be merely to “produce a new aircraft,” but to ensure that it is certified, sustainably manufactured, properly supported by Maintenance, Repair and Operation (MRO) and spare parts, and most importantly, backed by a real order backlog.

Defining the market: Civilian or military?

The first and most fundamental decision is to clearly define the intended user base − civil or military −because it dictates the entire architecture of the program, from certification standards to technology features and ground-based training systems (GBTS).

A civil trainer (for flight schools and cadet programs) must meet CS-23 standards, emphasize low cost per flight hour, and use modern glass-cockpit avionics compatible with commercial airliners. Reliability and ease of maintenance are key for this segment.

A military trainer, however, requires a completely different approach: greater flight envelope, higher G-limit, optional ejection seats, open mission computers for tactical training, and integration with simulation systems. This category targets the Indonesian Air Force and export markets currently recapitalizing their aging trainer fleets.

While modularity, designing a single base platform adaptable for both civil and military uses, seems attractive, it is only feasible if planned from day one. A halfway solution risks producing an aircraft that is “versatile but mediocre,” and likely to fail in both markets.

The program’s commercial viability depends on identifying concrete customers before finalizing the design. These include. First, Domestic civil operators, such as flight schools and aviation polytechnics, which require high utilization and affordable operating costs.

Second, Domestic military users, primarily the Indonesian Air Force for basic and advanced flight training. Third, Regional export markets in Southeast Asia, South Asia, Africa, and Latin America, where older trainer fleets are being replaced.

For the export segment, the aircraft must come with an integrated package: comprehensive training systems, MRO and spare-part pools, export financing schemes, and options for local industrial participation. Without pre-identified customers − preferably documented through Letters of Intent − the program risks repeating past failures: producing aircraft without buyers, or securing buyers without adequate maintenance support.

A project of this scale demands an integrated product team comprising experts in aerodynamics, structures, avionics, human factors, flight testing, certification, and manufacturing. Bandung remains Indonesia’s most capable base for such work, with existing facilities and skilled human resources.

However, roles must be clearly defined. Who will hold the design authority? Who will own the production certificate? Who will act as the type certificate holder (for civil variants) or military airworthiness authority (for defense models)? Any ambiguity in these areas could lead to disputes over certification, after-sales responsibilities, or export rights.

A full feasibility study (FS), covering technical, market, industrial, financial, and regulatory aspects, must precede the program’s launch. Past experiences of unfinished projects or grounded fleets due to spare-part shortages must not be repeated.

Design decisions must always be tied to two operational metrics: cost per flight hour and fleet availability. These are what real operators measure success by. The supporting ecosystem − MRO infrastructure, spare-part logistics, and data systems − should be planned from the very first production batch.

Given the scale of funding and its cross-administrative nature, the project must be governed transparently. Baseline budgets and schedules should be publicly stated, scope changes managed through a formal review board, and periodic technical and financial audits conducted.

User communities, civil and military, must be involved from the start to ensure that requirements remain aligned.

Success indicators must be published and measurable: certification milestones met on schedule, effective contracts (not just MoUs), local content targets achieved, on-time deliveries, and high fleet availability rates.

A marathon, not a sprint

If properly managed, the PTDI–KAI collaboration could represent a major leap for Indonesia’s aerospace ambitions. But it must be treated as a disciplined, long-term industrial program − one that defines its market early, commits to certification and support readiness from day one, and sustains financing across political transitions.

The lesson from past efforts is clear: Do not build first and look for buyers later, and do not sell what you cannot support. Aerospace is not a sprint; it is a marathon. The true measure of success is not just in producing a prototype that flies − but in maintaining an ecosystem that keeps the fleet flying, efficiently and sustainably, for decades to come.

The writer is Indonesian Air Force Chief of Staff (2002-2005) and chairman of Indonesia Center for Air Power Studies (PSAPI).