11 Hidden Causes of Long TAT in MRO Operations

Turnaround time (TAT) is one of the most closely watched performance metrics in MRO operations, yet it is also one of the most misunderstood. When repairs take longer than expected, the assumption is often that technicians are overloaded or that capacity needs to be increased. In reality, extended TAT is rarely caused by the pace of physical work. More often, it is the result of hidden gaps in systems, data, and process design that slow repairs down between stages, approvals, and handoffs. In this article, we will talk about the less visible causes of long turnaround time in MRO operations, and why addressing them requires structural, not reactive, solutions.

What Is Turnaround Time (TAT) and Why Does It Matter?

Turnaround time, commonly referred to as TAT, measures how long it takes for a part, asset, or unit to move through the repair process from start to finish. In MRO operations, this usually means the time between receiving an item for repair and returning it to service or back to the customer. While the definition sounds simple, the way TAT is experienced on the ground is anything but. It includes not only hands-on repair work, but also every pause, handoff, and waiting period that occurs along the way.

TAT matters because it sits at the intersection of customer expectations, operational efficiency, and revenue. Longer turnaround times can lead to delayed deliveries, missed service-level agreements, excess inventory buffers, and frustrated customers. Internally, extended TAT often signals deeper issues in process design, system configuration, or data flow. When teams understand why TAT matters, and what actually influences it, they can move beyond firefighting and focus on changes that improve performance in a lasting way.

Why TAT Delays Are Rarely About Speed

When turnaround time starts to slip, the instinctive reaction is often to look at how fast work is being done on the shop floor. More technicians, longer shifts, or tighter deadlines are common responses. However, in most MRO environments, long TAT is not caused by slow repair work. Technicians are usually productive and working at capacity. The real delays tend to happen before work starts, between repair stages, or after the physical repair is complete, when items are waiting rather than being worked on.

These delays are typically rooted in limited visibility, incomplete data, or poorly defined processes. Parts may be available but not visible to the work order, approvals may be required but not triggered automatically, or ownership rules may be unclear. Because these issues sit between systems, teams, and responsibilities, they are easy to overlook. They do not show up as obvious failures, yet they quietly extend turnaround time. Understanding this helps set the right expectation: improving TAT is less about pushing people to work faster and more about fixing the structural gaps that slow everything down.

The 11 Hidden Causes of Long TAT in MRO Operations

Long turnaround times are rarely the result of a single failure. More often, they are created by a series of small, often overlooked issues that accumulate across the repair lifecycle. These causes tend to sit outside the obvious repair steps, making them harder to spot and even harder to fix. Below are ten common but frequently hidden contributors to extended TAT in MRO operations.

1. Inventory Exists but Is Not Visible at the Right Moment

One of the most common sources of delay occurs when parts are technically in stock, yet unavailable to the repair order when they are needed. Inventory may exist physically in the facility, but if it is misclassified, placed in quarantine, tied to the wrong ownership, or not properly linked within the ERP system, it cannot be issued to the job. From the system’s perspective, the part might as well not exist.

This lack of visibility forces repair work to pause unnecessarily. Work orders sit idle while teams search for parts, request manual overrides, or wait for inventory status corrections. As a result, turnaround time stretches through repeated stop-start cycles, even though materials were present all along. When inventory visibility is not aligned with repair execution, TAT becomes unpredictable and difficult to control.

2. Customer-Owned Inventory Treated Like Company-Owned Stock

Customer-owned inventory introduces a different set of rules, but many MRO environments fail to reflect those rules accurately in their ERP systems. When ownership is not clearly defined at the system level, customer-owned parts are often processed as if they belong to the company. This creates confusion around valuation, consumption, and financial impact, especially at the point where repairs are ready to begin.

As a result, extra approvals, financial holds, or manual checks are introduced to avoid accounting or compliance issues. Teams hesitate to issue parts, unsure who is authorized to consume them or how they should be tracked. These uncertainties delay the release of work orders and push repairs into waiting status before any actual work has started. The impact on TAT is immediate and avoidable: repairs are delayed not by technical complexity, but by unclear ownership rules embedded in systems and processes.

3. Manual Work Order Handoffs Between Repair Stages

In many MRO operations, work orders move from one repair stage to the next through manual handoffs rather than system-driven workflows. Paper notes, emails, or spreadsheet updates are often used to signal that a task is complete and the next step can begin. While this may work in small volumes, it quickly becomes a source of delay as operations scale.

Without clear system-driven state changes, repairs frequently pause while teams wait for someone to notice that work is ready to move forward. Items sit in queues that are not visible in reports or dashboards, creating delays that are difficult to measure or explain. This “invisible queue time” quietly adds days to turnaround time, making TAT longer even though no one can point to a specific breakdown in the repair process.

4. Approvals Embedded in People Instead of Systems

In many MRO operations, critical approvals, such as releasing a job, approving an inspection, or closing out a repair, are tied to specific individuals rather than built into the system. Everyone knows who the “go-to” person is, and work often revolves around their availability. This approach may feel manageable at first, but it quickly becomes a bottleneck as volumes increase or priorities shift.

When those individuals are unavailable, busy, or transitioning work to someone else, repairs simply stop. There is no automated escalation, no visibility into pending approvals, and no logic to move work forward when certain conditions are met. As a result, turnaround time becomes inconsistent and unpredictable. Some jobs move quickly, while others stall for reasons that have little to do with the actual repair. These people-dependent approvals create fluctuating bottlenecks that quietly extend TAT and make planning difficult.

5. Incomplete or Inaccurate Master Data

Master data may not be the most visible part of an MRO operation, but it plays a critical role in how smoothly repairs move through the system. When lead times are inaccurate, routing steps are missing, or bills of materials are incomplete, the system cannot plan or sequence work correctly. Even small data issues can have an outsized impact once a repair is in motion.

Missing inspection steps or compliance requirements often surface late in the process, forcing repairs to be rerouted or paused while corrections are made. Teams may need to revisit work that was assumed to be complete, adding rework and additional approvals into the flow. These interruptions rarely show up as a single major issue, but they accumulate over time, creating repeated pauses that stretch turnaround time and make TAT harder to predict or improve.

6. Repair Priorities Are Not Systemized

In many MRO environments, repair priorities exist more in conversation than in the system. When everything is labeled as “urgent,” nothing truly is. Without clear, system-defined rules to sequence work based on service-level agreements, customer commitments, or asset criticality, technicians are often left to decide what to work on next.

This self-prioritization creates noise rather than focus. High-priority repairs can easily get buried among less critical jobs that happen to be more visible or louder in the moment. Over time, this lack of structured prioritization leads to inconsistent turnaround times and missed expectations. TAT suffers not because work is moving slowly, but because the right work is not always moving at the right time.

7. Quality Holds and Rework Are Not Tracked Properly

Quality holds and rework are an expected part of repair operations, but problems arise when they are not tracked with enough detail or visibility. When a repair fails inspection, the clock often restarts quietly, without clearly recording why the failure occurred or how long the item remained on hold. From a reporting perspective, the delay simply blends into the overall turnaround time.

Without capturing root causes, the same quality issues tend to repeat across jobs. Teams fix the immediate problem but miss the opportunity to address the underlying drivers of rework. The result is inflated TAT averages with little explanation, making it difficult to distinguish between unavoidable repair complexity and preventable process breakdowns.

8. ERP Is Not Configured for Repair Lifecycles

Many ERP systems are implemented with a strong manufacturing mindset, and repair operations are often forced to fit into workflows that were never designed for them. Manufacturing logic assumes predictable production steps, stable bills of materials, and linear processes. Repair work, on the other hand, is conditional by nature, what happens next often depends on inspection results, asset condition, or customer approvals. When ERP configurations do not reflect this reality, teams are forced to work around the system rather than with it.

Serial tracking is a common pain point in these environments. When it is incomplete or handled manually, teams lose visibility into where assets are in the repair lifecycle and what has already been done. This disconnect leads to frequent workarounds, manual updates, and off-system tracking just to keep work moving. Each workaround adds friction and delay, slowing down the overall process. Over time, these inefficiencies compound, making turnaround time longer and harder to control, even when repair volumes remain stable.

9. No Clear Definition of When TAT Starts and Ends

One of the most overlooked issues in managing turnaround time is the lack of a shared definition of when the clock actually starts and stops. In some teams, TAT begins when an item is physically received. In others, it starts only after inspection or formal release to the shop floor. Similarly, some groups stop the clock at repair completion, while others include packing, shipping, or customer acceptance. When these definitions vary, TAT metrics lose their meaning.

Waiting time is often excluded entirely or measured inconsistently, even though it represents a significant portion of total turnaround time. As a result, reports may show improvement that does not reflect real operational performance, or they may mask where delays are truly occurring. When teams cannot trust the data, improvement efforts focus on the wrong areas. Instead of fixing the structural causes of delay, organizations end up chasing symptoms, missing the real problems that continue to extend TAT.

10. Data Exists, but No One Owns TAT Performance

Most MRO organizations already have access to a significant amount of data related to turnaround time. Dashboards, reports, and KPIs may show average TAT, open work orders, or backlog aging. However, having data does not automatically lead to improvement. When no single role or function clearly owns TAT performance end to end, those metrics remain informative but not actionable.

TAT typically spans multiple teams, operations, inventory, quality, finance, and sometimes even customer service. Without shared accountability, delays fall into the gaps between these groups. Each team may optimize its own area, yet overall turnaround time continues to suffer. As a result, TAT often only becomes a topic of serious discussion when a customer escalates an issue or a service-level agreement is at risk. By then, the focus shifts to short-term fixes rather than structural change. Without clear ownership and coordinated accountability, the same delays repeat, and long TAT becomes an accepted part of doing business instead of a problem to be solved.

11. Vendor Delays and External Supply Chain Dependencies

Even the most well-designed repair operation can experience delays when work depends on external vendors. Specialized parts, outsourced repairs, certifications, or third-party inspections often sit outside direct operational control. When vendor lead times slip, change, or are not clearly visible in the system, repairs stall, sometimes indefinitely, while teams wait for components or services to arrive.

The challenge is not just the delay itself, but the lack of integration between vendor activity and internal repair workflows. Many MRO environments rely on estimated lead times, email updates, or informal follow-ups to track vendor progress. When a shipment is late or a service takes longer than expected, the repair order quietly remains in limbo. Without real-time visibility or automated alerts, these delays go unnoticed until they begin to impact delivery commitments. Over time, vendor-related pauses add significant, unpredictable time to turnaround, making TAT harder to manage even when internal processes are functioning well.

The Most Important Cause: No Dedicated Partner to Design and Own TAT Improvement

Even when organizations recognize the structural causes of long turnaround time, many struggle to turn that awareness into sustained improvement. Internal teams are often focused on keeping operations running, closing tickets, or meeting short-term deadlines. As a result, TAT initiatives remain fragmented, addressed in isolated process tweaks, manual workarounds, or one-off system changes that do not hold over time.

This is where having a partner like Epiphany makes a measurable difference. Rather than treating turnaround time as a shop-floor speed issue, Epiphany approaches TAT as a systems, data, and process design challenge. By aligning ERP configuration, inventory ownership rules, repair workflows, and performance metrics, Epiphany helps organizations move from reactive fixes to repeatable, scalable improvement. Without this kind of end-to-end ownership, TAT delays tend to persist, not because teams are not trying, but because the underlying structure has never been properly designed.

Wrapping Up

Long turnaround times rarely come down to one big problem. They are usually the result of small, compounding issues across systems, data, and handoffs that quietly slow repairs down over time. Once those hidden causes are understood, improving TAT becomes far less about pushing teams harder and far more about designing processes that actually support how repair work happens. If this article resonated, keep an eye out for our upcoming piece, A Practical Framework for Improving TAT in MRO Operations, where we will walk through concrete, step-by-step approaches organizations can use to address these challenges and achieve more predictable turnaround times.