March 08, 2023

Using a digital MEL to improve operational safety, compliance and lower costs

By Karl Steeves

Aircraft Minimum Equipment List (MEL) management and use plays a critical role in the safety and operational efficiency of an airline or business jet operator. Efficient use of the MEL allows for operational flexibility, but they also expose an operation to more risk — the airline or business jet operator is flying with inoperative defects unresolved. Today, the vast majority of operators use an iPad, displaying the PDF output of the MEL. And while this is an improvement on the paper-based MELs of years past, the MEL is being digitized as a software product coupled with a digital workflow, with benefits for operational safety, efficiency and costs. TrustFlight has developed a product called MEL Manager to address this potential and ease pain points.

The laborious task of creating MELs

The process of creating an MEL from a Master MEL is laborious. The MEL can quickly turn into a document with thousands of pages, depending on the complexity of the aircraft. MELs are cumbersome to create and update, with a whole cottage industry of suppliers seeking to convert existing paper versions.

A small, lean business jet operation may task a first officer to create and manage the MEL, on top of their flying duties. Such a strategy leads to shortcuts. Many business jet operators will take existing MELs from previous operations and find and replace words in the document. We’ve seen MELs with the names of three different former operators in the document!

A software-based solution for MELs — not just PDF versions

The process and conversion of a Word document to PDF is not digitization, in my view. With a digital solution, a business jet operator will receive a system fit for purpose. Changes become software-driven and not manually made. For instance, one aircraft — a Pilatus PC-12 may have a propellor with four or five blades, and of different materials. These variations dictate maintenance requirements. With TrustFlight’s MEL Manager, those variables can be input into the master MEL, with changes flowing down through individual MELs for individual aircraft. An operator can then pull the Master MEL and adapt small items without rebuilding the complete document every time.

MEL management must also scale as an operation does. For example, consider a business jet operator with 40 aircraft in the fleet. Reviewing preventative maintenance and formulating a plan takes time. It might take a team at a business jet operator two days to go through 40 aircraft records. Tracking MEL usage is not effective with Microsoft Excel, either. While a manual solution might suffice for a few aircraft, it will quickly be obsolete in as little as two to three years, depending on the operator’s ambitions.

Better communication between crew and maintenance

Operationally, MEL management can improve lines of communication between pilots and their counterparts in maintenance. A digital MEL can ensure a single source of truth — no longer are defects lost in a tech log that hasn’t been immediately communicated back to maintenance. Standardized responses reduce variability with a corresponding and immediate analytics benefit. Linking the MEL to the electronic tech log might reveal where a maintenance department is weak in certain ATA Chapters, and where technicians can potentially focus more on preventative maintenance instead of corrective maintenance. There is also a big safety and compliance benefit — with a paper MEL it’s common to mistakenly defer two items that are not compatible, or transcribe the wrong deferral interval. A digital MEL avoid this non-compliance by providing active validation and alerting at the point an item is raised.

Unlocking the data revealed in the MEL

Airlines and business jet operators frequently seek better analytics to guide their operational plans and safety outcomes. But obtaining desired analytical outcomes requires data recorded with sufficient detail, accuracy, and a degree of standardization.

Tracking repetitive aircraft defects through data analysis

A common example is repetitive defect monitoring, based on the ATA Chapter and Subsection. TrustFlight’s Reliability Analytics can indicate how frequently an airline or business jet operator is issuing defects per thousand flight hours, and how many MELs an aircraft carries per day on average. This gives the airline or business jet operator — even a regulator — a gauge of risk by airframe. Such risk assessment could prevent an aircraft from being grounded on the eve of a high-profile flight, and allow operators to always put their best foot forward when conducting missions. An operator could uncover practices that may lead to avoidable maintenance issues, and stop them in their tracks.

The analytics reporting from MELs are categorized by criticality and the turn-around time to rectify the defect. Maintenance planners can then better prioritize and assign resources to repair projects, depending on the severity of the issue, and potentially eliminate the need for large repairs that may require additional technicians than is required for smaller, targeted repairs.

TrustFlight Reliability Analytics

Proactive alerts for aircraft defect trends

Rather than waiting for maintenance technicians to identify problem equipment and trends, TrustFlight’s Reliability Analytics features an alert-based system to proactively flag issues and provide granular data to support a fix. For instance, an alert in the software identifies the specific ATA Chapter, and displays a chart for the user to see trends related to that Chapter. The system will also show the details of the defect, specific part numbers and the reason why the issue was raised. Defective parts can be examined to better understand the component performance metrics, and compare that to the OEM-stated performance.

Specific data for communication with OEMs and use of spares

Reliability Analytics allows an operator to be informed and raise data-backed issues to OEMs when necessary. Operators can flag to an OEM that the mean time between unscheduled removal (MBUR) numbers are not to stated performance. The data also allows an airline or operator to increase their spares but do so using analytics and metrics rather than guessing. This reduces the frequency of AOG (aircraft on ground) events.

The end result of MEL Manager and Reliability Analytics is a fleet of aircraft operating at their fullest potential, and less likely to encounter an issue when the fix is nowhere to be found. Pilots can better focus on doing their primary task of flying their aircraft, maintenance technicians can better plan their repairs, and airlines and business jet operators can reap the benefits of operation that’s more cost-effective and safe.

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