Each aircraft is subject to more than 2,000 maintenance tasks throughout its lifecycle. As history has shown us, even a few missed or improperly executed tasks can lead to catastrophic outcomes. These cases are a sobering reminder that strict adherence to maintenance schedules is not just a regulatory requirement, but a matter of safety and operational integrity.

Central to ensuring that no task is missed is a fundamental yet critical concept: LDND—Last Done, Next Due. This record helps operators track when a maintenance task was last performed and when it is next scheduled, ensuring all required tasks are completed within their defined intervals as prescribed by the OEM. It serves not only the purpose of preserving safety and airworthiness but also plays a key role in asset preservation, particularly during end-of-lease (EOL) transitions and redeliveries, where lease compliance is under intense scrutiny.

Understanding LDND and Its Function in Maintenance Planning

LDND forms the backbone of task tracking in aircraft maintenance. It ensures that scheduled inspections and component checks are not only conducted on time but are also properly documented for reference. For every task listed in the Maintenance Planning Document (MPD), the LDND ensures operators can quickly verify compliance and plan upcoming actions.

This becomes especially important when an aircraft approaches redelivery or registration transfer, where inconsistencies in maintenance program structures (AMP vs MPD), local regulations, or operator-specific practices can introduce challenges. In such cases, LDND data must often be reviewed, adjusted, and “bridged” to meet the requirements of the receiving entity or regulator.

LDND Bridging: A Critical Step in Redelivery

During redelivery, LDND records often require alignment—a process known as bridging—to reconcile differences between the outgoing and incoming maintenance programs. Several factors can drive this need:

• Regulatory Mandates: Some jurisdictions may impose additional tasks not covered by the previous AMP. These must be fulfilled either before or during the redelivery process.

  
  

• Task Numbering Variations: Operators may use unique task numbering systems in their MPD tracking. This necessitates careful mapping and validation of LDND records to ensure no tasks are overlooked.

  
  

• Interval Reductions: Some operators may voluntarily reduce task intervals within their AMP for higher fleet reliability. Upon redelivery, these modifications must be reverted to standard MPD intervals unless otherwise agreed with the lessors.

Such variations make LDND bridging a non-negotiable step to ensure compliance, maintain asset value, and facilitate a smooth transition between operators.

Managing LDND with AMS and ERP Systems

Many airlines manage LDND using Aircraft Maintenance Systems (AMS) or ERP software, which provide structured and traceable platforms for planning, executing, and reviewing maintenance tasks. These systems allow for streamlined scheduling, quick access to task history, and automated reminders to avoid oversights. However, smaller or startup operators sometimes rely on manual systems, typically using Excel spreadsheets. While cost-effective, manual tracking increases the risk of human error—such as missing tasks or duplicating entries—especially during high-pressure transitions like redeliveries.

Although LDND findings are relatively rare, they do occur. These include missed task entries, un-updated schedules, or inconsistencies following the release of a new MPD revision. Such errors, when caught late, can lead to delays, additional costs, or non-compliance notices during audits or transitions.

The Added Value of Digital LDND Tracking for Reliability Analysis

Beyond compliance, digitally managing LDND contributes to aircraft reliability analysis. A centralized ERP system retains historical task data, including intervals and recorded defects. This enables operators to identify patterns—such as recurring issues with specific components—and supports better decision-making for fleet-wide improvements.

Manual systems, on the other hand, often overwrite previous records or lack detailed audit trails, making it difficult to perform root cause analysis or build long-term reliability insights.

Conclusion

While transitioning from manual tracking to a software-based solution may seem daunting—especially in terms of data migration and upfront investment—the long-term benefits are significant. Increased accuracy, reduced administrative workload, and more effective maintenance planning ultimately translate to lower operational costs and higher fleet reliability.

Working with a technical partner like TBM Aviation, operators can ensure a smooth migration, customized setup, and ongoing support tailored to their fleet and regulatory environment. Our team brings hands-on experience in aligning LDND records for operational, leasing, and regulatory requirements.

For consultation or implementation support, contact us at info@tbmaviation.com.