Lessons Learned & Best Practices to Avoid AOG
AOG (Aircraft on Ground) events cost airlines and MROs in lost revenue, schedule disruption, and operational headaches. Rapid AOG response is vital, but a resilient spares ecosystem prevents issues before they escalate to AOG incidents.
Operators now face turbulence in parts availability, repair turnaround times, demand forecasting, and logistics. These pressures affect fleet reliability, cost control, and operational stability.
Over the past five years, the aviation industry has faced a series of supply-chain shocks that exposed weaknesses in traditional sourcing and inventory models. As fleets have grown, aged, and shifted under global constraints, airlines and MROs have learned that true reliability depends not only on how quickly they respond to disruption but on how effectively they prepare their supply chains to withstand it.
This is where resilient, future-ready spare parts strategies change the game, turning chaotic scrambles into predictable, controlled, and repeatable operations.
Aviation supply chains have always been complex, but today’s operating environment has introduced deeper structural challenges that operators must plan around.
“Aviation cannot function without a reliable supply chain. Yet today, grounded aircraft, delayed deliveries, and escalating maintenance and leasing costs are clear symptoms of a system under strain,” states Oliver Wyman and IATA in October 2025, “Airlines face long waits for engines and components, while OEMs, MROs, and suppliers are challenged by capacity and labor constraints, as well as fragile supply chains.”
Production disruptions on major airframes and engines have reduced near-term availability of both installed equipment and replacement components. Slower production rates, parts shortages, and quality investigations have created ripple effects that extend across fleets and regions.
Engine repair capacity has not kept pace with post-pandemic demand. In many cases, operators face historically high turnaround times, and certain engines or modules are now associated with lead times that can stretch well beyond a year, which pushes airlines to rely more heavily on rotable pools, leased engines, and alternative material sources to maintain readiness.
Used serviceable material has become a lifeline for operators looking to control costs and work around OEM lead times. At the same time, USM demand is growing at a mid-to high‑single-digit annual rate in many segments, so single-source USM strategies are increasingly insufficient in tight markets.
International freight networks continue to face unpredictable disruption from capacity constraints, extreme weather, port congestion, and geopolitical events. As a result, even routine component movements can be exposed to inconsistent transit times and unplanned delays.
Airlines are keeping older aircraft in service longer while also flying them harder to meet strong passenger demand. This combination drives more frequent shop visits and unscheduled removals, particularly for legacy components that are already scarce or no longer in production.
In short, operators are contending with more frequent disruptions, longer and less predictable lead times, and tighter material availability than at any time in recent memory.
“By our estimate, these challenges could cost the airline industry more than $11 billion in 2025, driven by a mix of delayed fuel cost savings, higher maintenance costs, and increased spares inventory,” says IATA.
The last five years of disruption have reshaped how resilient spare parts strategies need to operate. Operators are moving from lean, linear procurement models to flexible, risk-aware supply networks that can absorb shocks instead of simply reacting to them.
Lean or just-in-time inventory reduces carrying costs but increases exposure to unpredictable supply shocks. Operators that maintained strategic safety stock and rotable buffers generally saw fewer interruptions and faster recovery when disruptions hit.
Relying on a single primary supplier for a component category is no longer viable in a volatile environment. Diversifying vendors and regions spreads risk and gives operators more negotiating power, flexibility, and stability when any one source is constrained.
What began as a margin optimization tactic has become a frontline availability lever. Operators with robust USM partnerships, teardown access, and clear quality controls maintained better access to material and more control over total cost during recent shortages.
Repair turnaround times vary widely across shops, regions, and asset types. Airlines and MROs that benchmarked repair performance, monitored TAT trends, and pre-qualified alternate repair partners gained a measurable advantage when backlogs lengthened.
The shift is clear: resilient operators now design flexible, redundant spare parts ecosystems instead of relying on narrow, linear procurement paths that assume everything will arrive on time.
Strengthening supply‑chain resilience requires a deliberate strategy across sourcing, stocking, and supplier management.
A robust sourcing strategy goes beyond a single primary parts supplier. Resilient operators build:
This kind of redundancy helps maintain parts flow even when one channel faces disruption.
The goal is not simply to stock more, but to stock smarter. A resilient inventory design typically includes:
Airlines with structured, multi-tiered inventory systems tend to experience fewer shortages and faster maintenance cycles.
A supplier’s own resilience directly affects an operator’s reliability. Key indicators include:
Suppliers with robust, well-governed networks reduce operational vulnerability for airline and MRO partners.
Visibility across the supply chain helps operators spot risks before they impact operations. High-performing organizations emphasize:
Industry studies suggest predictive maintenance can significantly cut unplanned outages and improve parts planning, with some programs reporting double-digit reductions in unscheduled events when these tools are fully embedded.
Resilient supply chains deliver measurable benefits across common operational challenges by keeping parts flowing when the system is under stress.
Operators with rotable pools, leased engines, and reliable USM access can keep aircraft flying while others sit in long shop queues. These strategies help absorb extended turnaround times and protect schedule reliability.
Airlines that built multi-source vendor networks and qualified alternate manufacturers were able to secure inventory more quickly. Carriers dependent on a single primary supplier for line‑replaceable units often saw longer lead times and more frequent AOG risk.
Suppliers with teardown partnerships, deep USM pipelines, and legacy platform expertise have helped operators sustain older fleets. This reduces time spent on one-off searches and can limit exposure to extreme premium pricing for last-minute buys.
Operators with geographically diverse sourcing and stocking locations are better positioned to mitigate weather-related, seasonal, or geopolitical disruptions. When one region slows, material can still move through alternate routes and partners, supporting predictable maintenance plans.
Taken together, these scenarios illustrate how resilient spares strategies reduce the frequency, duration, and severity of operational disruptions rather than simply reacting after an AOG occurs.
Resilient spare parts strategies require partners who maintain material flow while supporting proactive planning.
Source One Spares helps airlines and MROs build stronger, future-ready supply chains through extensive global sourcing across OEM and USM channels, traceable inventory covering major ATA chapters, teardown-driven access to high-demand and legacy components, and rotable exchange and repair management backed by rigorous quality standards.
With over 25 years in aviation parts and supply-chain management, Source One Spares helps operators reduce costs, increase availability, and minimize downtime.
To strengthen your supply-chain strategy and ensure dependable access to critical parts, connect with Source One Spares today.