The MC-21 program has quietly emerged as one of the most interesting aviation developments of the past decade: a modern single-aisle Russian aircraft engineered to compete with Airbus and Boeing in terms of efficiency, cabin comfort, and operational cost-effectiveness, yet introduced into a notably challenging geopolitical and industrial context. The decision to deploy a fully import-substituted MC-21-310—meaning an airframe equipped with domestically produced components and engines instead of Western suppliers—has mitigated certain supply chain risks while introducing others: weight and performance compromises resulting from replacing some composite parts with locally sourced alternatives, and the requirement for domestic engines that either match or closely approximate the fuel efficiency, thrust, and durability of Western counterparts. The most apparent technical measure to restore margin is the implementation of higher-thrust engines. The two viable options for Irkut/United Aircraft Corporation are an upgraded variant of the PD-14 family (such as PD-14M or PD-16) or a PD-18, occasionally referred to in Russian sources as PD-18R. The latter is a heavier, more powerful derivative with approximately 18 tonnes of takeoff thrust. Both options are feasible; each entails its own set of trade-offs. Altitude Addicts, a YouTube channel, examines the technical rationale for increased propulsion on the MC-21-310, analyzes the PD-family roadmap, and evaluates how a PD-18 option would compare against Airbus and Boeing engine-airframe configurations in the marketplace.
Why the MC-21-310 might need more thrust
When an airliner undergoes a redesign or modifications to its design components—such as changes in structural materials, supplier adjustments, or the installation of domestically sourced equipment—its weight may gradually increase. The MC-21-310 program has had to incorporate extensive import substitution due to sanctions and supply disruptions that have rendered certain Western systems and materials more difficult to obtain. These substitutions can increase the empty weight and occasionally alter aerodynamic or system margins, thereby reducing payload-range capacity and climb performance.
Improving or restoring performance under such conditions can be achieved through weight reduction—which constitutes a lengthy and incremental engineering process—or by increasing installed power and optimizing engine efficiency. For the MC-21-310, the most feasible short-term approach is to use a partially upgraded engine to compensate for the increased weight and to facilitate extended-range variants, such as the 7,000 km version. Russian sources and industry analysts affirm that improving range and fuel efficiency continues to be a key focus, with engineers identifying both airframe weight reduction and engine advancements as the primary pathways to achieve these objectives.
The PD-14 family and its higher-thrust variants
The PD-14 (made by Aviadvigatel) was designed as a modern high-bypass turbofan engine for the MC-21 and serves as the preferred domestic powerplant for an entirely import-substituted version. The baseline PD-14 engine generates approximately 14 tonnes of thrust and has been formally certified and flight-tested as part of the MC-21 test program; domestically powered MC-21-310 prototypes have already conducted flights equipped with PD-14 engines. However, the PD programme was developed as a comprehensive family: variants with varying propulsion capacities, both lower and higher, were initially envisioned, bearing designations such as PD-8, PD-10, PD-14M, and PD-16, along with plans for much bigger engines like the PD-35 intended for wide-body platforms. Russian technical literature and industry reports expressly identify a potential uprate based on the PD-14 engine (occasionally referred to as PD-16 or PD-14M) as well as a separate PD-18R variant designed to achieve approximately 18 tonnes of takeoff thrust. Those higher-thrust derivatives are the most clear options for improving the MC-21’s climb and cruise performance in the event of increased mass or the need for a longer-range variant.
An improved variant of the PD-14 derivative offers two immediate advantages. At first, it leverages the PD-14 core along with a significant portion of the supply chain and manufacturing tooling, thereby reducing development time and maintaining lower costs compared to a completely new engine. Second, a modest increase of approximately 10–20% can often be realized through the addition of low-pressure compressor and turbine stages, enhancements in materials and control software, or modifications to the fan diameter and nacelle, thereby avoiding a complete redesign. This renders a PD-16 or PD-14M an appealing intermediate option for restoring reduced performance without requiring an enormous investment.
The PD-18R idea: 18 tonnes of thrust and a different architecture
The PD-18 (commonly referenced in Russian media as PD-18R, with R denoting a reduction transmission) emerges as a more advanced member of the PD series. Published Russian technical commentary and engineering blogs discuss proposals for an 18-tonne-class PD-18R that could be used on heavier narrowbodies or designated transport aircraft. A PD-18-class engine would offer an ideal propulsion margin for the MC-21-310 when the airframe is subjected to additional weight or when a long-range, high-payload mission is necessary. However, transitioning from a PD-14 to a PD-18-class engine is not just a matter of increasing power: it typically necessitates modifications to the fan diameter and low-pressure spool architecture and may involve the integration of a geared fan to regulate rotational speeds and reinforced pylons and nacelles, as well as meticulous revalidation of vibration characteristics and aerodynamic compatibility with the wing and pylon. In summary, the PD-18 appears viable on paper and within Russian design roadmaps, and public commentary has consistently regarded the 18-ton figure as the logical larger counterpart to the PD-14 family. However, transforming it into a certified, low-TSFC (thrust-specific fuel consumption) production engine requires significant time, financial investment, and testing resources.
Performance trade-offs and system implications
Integrating a higher-thrust engine yields immediate advantages in takeoff performance, initial climb, and the capacity to maintain high cruise speeds or accommodate increased fuel and payload for extended ranges. However, penalties must be taken into account. An engine producing 18 tonnes of thrust is larger and heavier; its nacelle and pylon loads alter the local wing bending moments; the engine’s weight influences the aircraft’s center of gravity; and higher-power components may exhibit different fuel consumption characteristics during cruise if not paired with a modern, high bypass ratio core. A well-engineered PD-18R featuring a high bypass ratio and contemporary composite fan has the potential for efficiency during cruise; however, this outcome is not guaranteed. Development duration and certification risk are also high: a PD-18 will require performance testing, frost and volcanic ash assessments, birdstrike validation, and the establishment of an airline support network for spare parts and maintenance, repair, and overhaul services. The designer’s challenge is therefore to select a variant that optimally balances the requirement for additional propulsion with the associated penalties to empty weight, acquisition cost, and lifecycle expenses. Russian reports on the MC-21 program indicate that engineers are aware of these trade-offs and that extending the range to approximately 7,000 km will require both advancements in propulsion technology and ongoing efforts to reduce airframe weight, rather than relying solely on propulsion enhancements.
Two-engine option strategy: why offering both an uprated PD-14 and a PD-18 makes sense
From a commercial perspective, providing two engine options is rarely a mistake when product differentiation is well-defined. Airbus and Boeing have long recognized that varying airline missions and operational models require different thrust classes and fuel efficiency profiles; this is the rationale behind the A320neo family’s support for both the CFM LEAP-1A and Pratt & Whitney’s PW1100G engines, and why Boeing adopted the LEAP-1B as a single-source option, customizing it for the 737 MAX. For the MC-21, a PD-14 engine (with minor uprates) would adequately serve the majority of short- to medium-range operators seeking competitive fuel efficiency on high-frequency routes. An option for PD-18 would attract operators requiring enhanced payload-range capacity, improved performance on rough fields, or greater resilience at hot-and-high airports. Additionally, it would enable Irkut to promote a longer-range MC-21 variant without the delay of extensive airframe modifications. In summary, a dual-engine strategy reflects the market approach employed by Airbus and Boeing: offering airlines a choice between a reduced purchase price with optimal fuel efficiency (smaller engine) or enhanced capability and margin for specialized missions (larger engine). The PD family roadmap explicitly considers multiple propulsion ratings and derivatives, thereby supporting this modular approach.
How the MC-21 + PD-18/PD-14M would compare with Airbus and Boeing single-aisle pairs
It is beneficial to include numerical indicators alongside the competitors. The Airbus A320neo family is currently equipped with either the CFM LEAP-1A engine, which delivers maximum takeoff thrust of approximately 35,000 lbf (~156 kN) in its upper variants such as the A321neo, or Pratt & Whitney’s geared PW1100G series, offering thrust ratings ranging from approximately 24,500 to 35,000 lbf depending on the specific model. Boeing’s 737 MAX family employs the LEAP-1B engine scaled down to 28,000 lbf for the MAX variants. Those Western engines incorporate sophisticated high-bypass configurations, established service networks, and exhibit remarkably low specific fuel consumption during cruise within their thrust ranges. A PD-18 would therefore be required to demonstrate competitive TSFC and maintenance costs during operation to be commercially viable in comparison to established products. The PD-14 family was developed as a modern engine, and its performance assurances position it within the same general category as the LEAP and PW1000G under specific operational conditions. However, the PD-18 must be examined based on actual cruise TSFC, time-between-overhaul performance, and lifecycle reliability. If Russia is able to manufacture a PD-18 engine featuring an optimal bypass ratio and minimal maintenance requirements, the MC-21 could establish credible competitiveness in terms of payload-range and travel cost within certain operator segments.
Operational and industrial conditions: certification, assistance, and penalties
Technical feasibility represents merely one aspect of the overall narrative. Engines are considered system-level products: spare parts, maintenance, repair, and overhaul capabilities, supply chains for specialized alloys and composites, and regulatory approvals are often as critical as the propulsion specifications detailed in the brochure. The first international launch plan for the MC-21 comprised Western engines, including Pratt & Whitney’s PW1000G family; however, due to sanctions and export restrictions, Irkut expedited the adoption of the PD-14 to produce a wholly import-substituted MC-21-310. That decision reduces dependence on international suppliers but necessitates Russia to develop comprehensive domestic certification documentation and establish a service network for the PD family. UEC reports indicate ongoing efforts in testing and scaling up production of the PD-14, while also referencing the broader ambitions of the PD family. However, developing a PD-18 at commercial scale would represent an important step, necessitating the establishment of test facilities, endurance testing, volcanic ash resistance assessments, and foreign airworthiness certification should Irkut seek to expand sales beyond restricted markets. For operators within Russia and allied markets that recognize Russian certification, the threshold is reduced—however, maintaining global competitiveness necessitates demonstrated life cycle economics.
Bottom line: PD-14 provides short- to medium-term enhancements, while PD-18 focuses on capability expansion.
Consequently, a practical programme roadmap materializes. In the short term, Irkut and Aviadvigatel will focus on the serial production of the PD-14 and implement modest uprates (PD-14M / PD-16-class modifications) to restore performance previously affected by import substitution and to ensure the continued progress of MC-21-310 deliveries. These derivatives are associated with reduced risk, leverage substantial portions of the existing engineering foundation, and deliver quantifiable enhancements in performance. Meanwhile, the PD-18R concept continues to be an appealing long-term option that could facilitate higher-payload and extended-range MC-21 variants, including the 7,000 km range concept occasionally referenced by the program. However, the development of PD-18 will require greater investment, additional testing, and more time to reach a production-ready level. If Russia can implement this dual-track approach—producing both serial PD-14 and PD-14M engines for the fleet, alongside the development of PD-18 for future capability enhancement—the MC-21 will retain its adaptability and be capable of providing various mission profiles to diverse clients. This reflects the approach taken by Airbus and Boeing in managing their narrowbody families: offering multiple engine options and implementing incremental enhancements to maintain the relevance of the product line throughout its production lifespan.
Final reflections: market segments and the strategic significance of the MC-21
Ultimately, the necessity of a PD-18 is contingent upon the target market that Irkut aims to serve. For most short-haul, high-frequency routes—the core operations of A320 and 737 operators—a properly implemented PD-14 or PD-14M engine that aligns with Western engines in terms of TSFC, reliability, and maintenance costs will be adequate. For specialized missions, high-payload routes, airports with sweltering and high conditions, or a stretched long-range MC-21-400 variant, the 18-tonne-class PD-18 would serve as an attractive option. The technical rationale, family-level planning within Aviadvigatel, and various Russian industry analyses all endorse the hypothesis proposed by the user: a PD-18 (approximately 18 tons) represents a natural larger counterpart within the PD program, while upgraded PD-14 derivatives constitute the most viable near-term solution. Implementing both sequentially would provide MC-21 operators with genuine options—and enhance the program’s prospects of narrowing the gap with Airbus and Boeing in terms of performance and market adaptability.
