The Economic and Operational Dynamics of the Rotables Segment

Introduction

I wrote an article on this topic in 2023 which was a nice introduction to the rotables economy but I wanted to update my writing with more relevant information and a better explanation of how rotables programs work in our industry. That being said, enjoy the read. Let me know if you have anything to add to this and I would love to include you in an article update!

Article

Our incredible industry, the global aviation industry, with its vast expanse and crazy intricate operations, is a jaw-dropping marvel of modern engineering and logistics. Incredible feats of engineering, led by our beloved Boeing, and other fine aerospace contributors, and used every day by some of the worlds largest operators like Scott Kirby's United Airlines, and the late Fred Smith's FedEx (a truly remarkable contributor to global aviation). Among its many critical facets, one segment that plays a pivotal, yet often remains behind the scenes role, is the world of rotables. These sophisticated, high-value aircraft components are fundamental to maintaining the operational efficiency, safety of our NAS, and economic viability of global air travel. I attempt to write a comprehensive article will delve into what rotables are, how their specialized segment operates, explore the rigorous standard practices surrounding their sale and purchase, and provide an in-depth look at the industrys market size, economic drivers, and future trends.

Lets take a quick look at the market we all proudly serve, until its Friday at 4:46PM and the phone starts to ring off the hook with clients/operators that have waited until the last minute to handle their aircraft's affairs and have the desire to fly their broken airplane on Saturday. We all know what I am talking about here...

According to Fortune Business Insights, the global aircraft aftermarket parts market size was valued at USD 48.71 billion in 2024. It is projected to grow to USD 93.52 billion by 2032, exhibiting a Compound Annual Growth Rate (CAGR) of 8.0% during the forecast period (2025-2032) [Source: Fortune Business Insights, Aircraft Aftermarket Parts Market Size, Share amp; Forecast [2032]

Another fantastic report I found from Polaris Market Research estimated the commercial aircraft aftermarket parts market at USD 44.45 billion in 2024, projecting growth to USD 74.66 billion by 2034 with a CAGR of 5.4% (2025-2034) [Source: Polaris Market Research, "Commercial Aircraft Aftermarket Parts Market Report, 2034"]. Fortune Business goes on to say, he "rotable replacement parts" segment is specifically anticipated to exhibit the highest CAGR within the broader aftermarket parts market, indicating its increasing importance and value (also from the same linked source provided above).

So, we can all conclude this: Our little (kind of big) world is looking real hot! What is driving all of this growth and excitement? My little list of economic and market influences are below:

• Expanding Global Fleet: As all of us working in this industry know, the primary obvious driver is the continuous growth of the global commercial and general aviation fleets. As more aircraft enter service, the demand for maintenance, repair, and replacement parts, particularly rotables, naturally increases. Airbus, for instance, projects that the passenger fleet could double from 21,000 aircraft in 2019 to 45,000 by 2035, directly fueling MRO and parts demand [Source: Fortune Business Insights citing Airbus SAS]. We all know, airplanes are built to last for at least a half a century or more. There are more birds being released into the wild than birds that are retiring!
• Aging Aircraft: A significant portion of the global fleet is aging (similar to our aging population), leading to more frequent and complex maintenance requirements, which heavily rely on rotable exchanges and overhauls. Older airplanes means more MRO, more inspections, more parts, more rotables, more fuel, and more fun.
• Increased Flight Hours/Cycles: The anticipated rebound in air travel, post-pandemic, translates to higher aircraft utilization, accelerating wear and tear on components and thus increasing the demand for pilots, mechanics, a better run value chain and of course, rotable replacement and overhaul services.
• Focus on Operational Efficiency & Cost Reduction: Airlines and operators are constantly seeking ways to minimize aircraft downtime (AOG costs can be $10,000 to $50,000 per hour for larger aircraft), horrible migraine headaches for us in the value chain, while optimizing maintenance costs. Rotable exchanges provide a fast, cost-effective solution compared to waiting for a repair, or buying new if a component even still exists and is available in that condition.
• Supply Chain Resilience: The aviation supply chain has faced significant horrific challenges, including continued workforce and material shortages, post-pandemic. This emphasizes the need for supply side evolution, as well as robust rotable management systems to ensure parts availability and mitigate disruptions [Source: U.S. GAO, Commercial Aviation Manufacturing: Supply Chain Challenges and Actions to Address Them].
• Technological Advancements: While new aircraft feature advanced, more reliable components, these often come with higher initial costs and complex repair procedures, potentially increasing the value and lifespan of each rotable. Predictive maintenance technologies, leveraging advanced sensors and now AI, are also emerging to optimize rotable removal intervals and improve maintenance efficiency [Source: AviTrader, "Rotables – Repair or Replace?"].
• Regulatory Compliance: Strict aviation regulations (FAA, EASA, ICAO) mandate meticulous tracking and certification of parts, driving the need for sophisticated documentation and quality assurance throughout the rotable lifecycle. This regulatory environment underpins the integrity and trust within the market. And in case you havent noticed, the regulators are regulating more and more each year, driving up costs and making it more and more difficult to participate in our industry. A fun side note, I remember doing touch and go's at Washington National (KDCA) at 2AM with my friends in a Cessna 210 at 2AM for fun while in my early 20's. Imagine that... never again!
• PMA Parts Growth: Parts Manufacturer Approval (PMA) parts, which are FAA-approved non-OEM alternatives, are gaining traction. This market is explosing! These alternative part solutions often offer cost savings (sometimes 30-50% less than OEM parts) while meeting the same airworthiness standards, contributing to market competition and economic efficiency. This segment is growing fast. Imagine, under Rhett Ross, and after becoming Chinese owned, our very own Continental Motors started producing alternate parts for use on Lycoming engines. Super interesting!

What in the World are Rotables? A Foundation of Reusability

Rotables are defined as aircraft components that can be repeatedly and economically restored to a fully serviceable, airworthy condition after they have reached a defined service interval or exhibited a fault. You pull the bad or expired part off the airframe, and you rotate a new or overhauled part on the airframe. You send the bad part back and it completes its cycle and starts over again after it gets refurbished. A complete lifecycle rotation! This cyclic rotation of that part on and off the airframe is how we come up with the term, rotable.

However, unlike consumables (parts discarded after a single use) or simple repairables (parts fixed to a serviceable condition but not necessarily to as new standards), rotables generally undergo a comprehensive overhaul process. This meticulous refurbishment restores them to Original Equipment Manufacturer (OEM) specifications, allowing them to be returned to service, often multiple times over their lifespan, thereby significantly extending their economic utility. My boy Ryan S. over at Power Packs Plus has mastered this game for the general aviation industry and they have earned a position as a premier provider for AirParts Aero.

For those of you that may not know the types of things you will find in a rotable pool, lets look at some examples of high-value rotables, components that are diverse and critical to aircraft function:

• Landing Gear Assemblies: Essential for safe take-off and landing operations. Ever try landing without them or just forgot to gear down before touchdown? Suuuucks!
• Aircraft Engines and their Major Accessories: Such as fuel controls, generators, and hydraulic pumps. Even engines are a rotable item.
• Complex Avionics Systems: Including Flight Management Systems (FMS), Communication Navigation Surveillance (CNS) units, and Integrated Modular Avionics (IMA).
• Actuators: Crucial for controlling flight surfaces and various mechanical systems that allow our winged loved ones to remain under human control.
• Auxiliary Power Units (APUs): Providing essential power for aircraft systems on the ground, and once in a blue moon, in the air in the miraculous and amazing case of Captain Sully and his non-checklist decision to turn on the APU to get some form of control over his iron lady as he steered his girl with precision into the Hudson river.

In a little bit more detail, the operation of the rotables segment is characterized by a precise and continuous cycle, which we all follow, and should respect:

1. Usage & Monitoring: A rotable part is installed and utilized in an aircraft. Its performance is continuously monitored, and its operational hours/cycles are tracked meticulously (one would hope) against manufacturer specifications and regulatory requirements.
2. Removal (Unserviceable): Once the part reaches a defined service interval, exhibits a fault, or is deemed unserviceable, it is removed from the aircraft. This removal triggers the need for a replacement part to ensure minimal aircraft downtime.
3. Refurbishment/Overhaul: The unserviceable part (the "core") is then sent back to the manufacturer or to a certified MRO facility operating under the requirements of regulation Part 145. Here, it undergoes a comprehensive overhaul, repair, or modification process. This involves disassembly, detailed inspection, replacement of worn or failed components with new parts, reassembly, and rigorous testing to bring it back to a fully airworthy and serviceable condition, most often with a new service life limit.
4. Certification: Upon successful refurbishment, the part receives new airworthiness documentation (e.g., FAA Form 8130-3, EASA Form 1), certifying its compliance with regulatory standards and its readiness for reinstallation.
5. Reinstallation/Inventory: The now serviceable rotable is either placed into strategic inventory to support future operational needs or immediately reinstalled in an aircraft. This cyclical process is crucial for maintaining a healthy supply chain and reducing the overall cost of aircraft ownership.

Standard Practices for Selling and Purchasing Rotables

The sale and purchase of rotables are governed by stringent protocols to ensure the highest standards of safety, compliance, reliability, and economic viability are adhered to.

• Comprehensive Documentation & Traceability: This is paramount, super important! Every rotable transaction must be accompanied by a complete suite of documents, including the airworthiness approval tag (e.g., FAA Form 8130-3, EASA Form 1), historical records (detailing time in service, cycles, repairs, modifications), and a Certificate of Conformance (CofC), FAA 8130-3, EASA Form 1, or similar. This (we love to use this term) "birth-to-death" traceability provides an unbroken chain of custody and verification, crucial for airworthiness and counterfeit prevention [Source: FAA Advisory Circular 20-154A, Pilot John blog on Traceability]. While "back-to-birth" traceability for all parts is not universally mandated, it is a common industry standard for critical and life-limited components. My strat team at AirParts.aero is creating an awesome system which we will release in April 2026 that will use blockchain, AI, and some other cool tech stuff to attempt to develop a global system of trace management. Stay tuned and yes, we think this document thing is one of the most important parts of our industry that still remains dated back in the 1970's.
• Crazy Rigorous Quality Assurance (QA): Reputable sellers, like AirParts.aero of course, OEMs, and MROs implement comprehensive QA programs. This involves meticulous incoming inspection of cores, in-process quality checks during overhaul, and stringent final testing. Before a sale, rotables undergo detailed assessments to ensure they meet or exceed OEM specifications and regulatory standards. It is super important to understand the system of standards of the supplier you are buying from. We are delighted to have our standards administered by Michele Dickstein and her truly audit heavy Aviation Suppliers Association, keeping us all in check.
• Warranty Provisions: Warranties are a two way street. They force the manufacturer or overhaul organization to build and refurbish to the highest standards. No service provider wants an item or aircraft coming back due to junky workmanship. The costs are way too high for providers. Additionally, to instill buyer confidence, Sellers typically provide warranties for overhauled or repaired rotables. These warranties cover material and workmanship for a defined period or operational cycles, protecting the buyer against premature failure. Buyers look for warranties to reduce risk and make sure the provider has "skin in the game." Remember when Kia first entered the USA? No one knew who the hell these people were but they offered a 100,000 mile warranty, unseen before in the auto industry. They took market share pretty quickly as the risk for the consumer was nearly gone and covered at least half of the vehicles life.
• Condition Codes: Parts are always classified by their condition (e.g., NE - New, NS - New Surplus, OH - Overhauled, RP - Repaired, SV - Serviceable, AR - As Removed). Buyers must understand these codes and ensure the condition meets their operational and regulatory needs. Buyers must also be fully aware of these distinctions as they directly impact price, remaining life, and applicable warranties. I wrote a few articles that detail each of the approved IATA condition codes. The links are <HERE> and <HERE>, if interested.

Core Exchanges and Core Deposits: The Economic Engine

A core exchange is a fundamental and economically vital practice in the rotables segment. It allows owners and operators to receive a serviceable, refurbished part (the exchange unit) immediately from a supplier, in return for their unserviceable part (the core).

• The Exchange Process: When an aircraft operator requires a replacement rotable, particularly for an inspection, a service visit, or more critically, an Aircraft on Ground (AOG) situation, they can opt for an exchange. This significantly reduces downtime compared to sending their unserviceable part in for repair and waiting for its return. With the current supply chain situation that we are all devastatingly enduring right now, this could take weeks to months. Not a great option unless the airplane is OK to just sit, sit, and keep sitting.
• The Core Deposit: To incentivize and guarantee the return of the unserviceable core, suppliers charge a core deposit. This deposit, often a substantial percentage of the exchange unit's value, is fully or partially refunded once the supplier receives the core and deems it repairable within agreed-upon limits. Usually the deposit is fully refunded if the core is inspected and it is found to be of normal use and wear. At times however, if the core being returned has just been beaten to death, and its condition warrants more service than is expected, and the additional service or parts are outside of the normal wear, money from the deposit would be used to cover the costs above and beyond the normal overhaul or return-to-service of that core item. This is called a charge-back and those costs are paid by the core deposit funds. The balance is then returned to the Buyer once the overhaul is complete.

Why is a Core Deposit Critical?

The core deposit serves multiple, intertwined purposes that underpin the entire rotables ecosystem:

• Ensuring Supply Chain Continuity: The rotables business model thrives on a continuous flow of unserviceable cores that can be refurbished. Every time we lose a core, its like a punch in the stomach. These babies are valuable to the world! Therefore, the core deposit is the primary financial incentive ensuring operators return these parts promptly, preventing depletion of the supplier's repairable inventory. Without this financial incentive, cores might be delayed or never returned, disrupting the supply chain.
• Economic Viability of Refurbishment: The rotables business model hinges on the continuous refurbishment of cores. Suppliers invest heavily in MRO facilities, specialized tooling, buying initial cores, and skilled technicians. Their profitability relies on consistently receiving cores to overhaul.The deposit secures the continuity of this cycle.
• Inventory Management: Core deposits help suppliers maintain a steady and predictable inventory of cores awaiting refurbishment allowing for more accurate forecasting of repair shop workloads and ensuring a consistent supply of raw material parts needed for repairs. This enables them to provide consistent "exchange units" to the market, which is crucial for supporting global fleet operations.
• Risk Mitigation for Beyond Economical Repair (BER) or Abnormal Damage: Not all cores are created equal. Some may be returned in a condition that is Beyond Economical Repair (BER) due to severe damage, pilot abuse (which one of us winged hotshots is not guilty of that) or excessive wear, making the cost of repair exceed the value of a new part. Others might have sustained abnormal damage (e.g., from a hard landing, again pilot problem, or unapproved repair attempt). The core deposit allows suppliers to recover costs associated with these challenging cores, with additional charges deducted from the deposit, ensuring the financial integrity of the overhaul process. This allows for fair compensation for atypical repairs.

A Real-Life Example: Optimizing Operations with Core Exchange on AirParts.aero

Consider Liberty Air Charters, a premier on-demand charter service based in Manassas, Virginia, in our beautiful United States of America, boasting a fleet of sleek Learjet 60 aircraft. Every 600 flight hours, per OEM requirements and in accordance with (IAW) the aircraft's repair and service manual (RSM), the Learjet's stabilizer actuator (example part number 5435005-028, commonly known as the "stab actuator") necessitates a comprehensive service according to its maintenance schedule.

The Director of Maintenance (DOM) or his or her team oversees the removal and inspection of the unserviceable actuator. To minimize aircraft downtime, the parts manager accesses their account on our platform (www.airparts.aero) to initiate a core exchange.

Promptly, AirParts.aero dispatches an already overhauled stab actuator to Liberty. Upon its arrival, Liberty's team installs the newly received actuator, ensuring the Learjet is swiftly returned to service. Concurrently, they prepare the old, removed from the airplane, unserviceable actuator for return to AirParts.aero. This returned core is then forwarded by AirParts.aero to one of its certified overhaul partners for refurbishment.

To ensure the timely return of the old actuator, Liberty placed a core deposit with AirParts.aero during the initial purchase. This deposit not only guarantees the part's return but also facilitates its repair and overhaul, as it provides financial security for us (AirParts.aero). If the returned actuator from Liberty exhibits issues beyond regular wear and tear (e.g., damage from an accident, corrosion beyond standard repair limits), the overhaul process incurs additional, atypical costs for AirParts.aero's overhaul partner. These extra expenses, stemming from damage exceeding "normal core repair" definitions, are subsequently billed to Liberty and deducted from the initial core deposit. Once the overhaul is complete and all associated costs settled, AirParts.aero refunds the remaining core deposit to Liberty, providing a detailed breakdown of any additional repairs and parts procured for the overhaul, ensuring full transparency. This is what I mentioned above, and I hope this scenario provides a more real-life perspective on how this would work.

Conclusion

Rotables are the indispensable, unsung heroes of the aviation industry (in addition to the A&P mechanics who never seem to get any praise for the amazing work they do to keep our birds in the sky), enabling the relentless cycle of flights that has come to define modern air travel. Their robust design, coupled with a sophisticated ecosystem of MRO facilities, expert suppliers, and meticulous documentation, ensures that aircraft remain operational, safe, and economically viable. The standard practices surrounding their sale, purchase, and the ingenious system of core exchanges are meticulously designed to uphold the highest standards of safety, efficiency, and supply chain continuity. As global air traffic is projected to continue its robust growth, the demand for efficient rotables management and the expansion of the aftermarket parts segment will undoubtedly remain a cornerstone of the aviation industry's success, continuously evolving to meet the demands of an ever-expanding and increasingly complex global fleet. We here at AirParts.aero have a sizeable core and rotables pool of inventory. We are ready to dispatch whatever you may need at a moments notice and can get our rotables to almost every corner of the non-sanctioned world either same-day or within a day. Let us know how we can help, oh... also, check out our awesome new ProSourcing program, its a game changer!

About the Author

Roland Pinto is the founder and CEO of AirParts Aero. A licensed pilot with over 15,000 PIC hours in over 50 different aircraft, Roland enjoys sunsets in the cockpit, and the speed of direct flight paths and puffy clouds. Throughout his over 25 year career in aviation, he has owned almost every type of air carrier certificate available; P121, P135, P141, P145, and an aircraft OEM with six type certificates. He has the honor of having one of his aircraft  on permanent exhibit at the Smithsonian National Air and Space Museum. AirParts Aero was built to solve a problem he had within his network of MROs back in 2018 and he and his team have evolved the company to become the first, high value-add, transactional-based multi-vendor marketplace in aerospace while also providing a masterfully created portfolio of services and tools to support industry stakeholders.