Technical Dispatch Reliability is one of the most important overall performance metrics that is used to monitor the reliability of the airline’s Engineering & Maintenance activities. It is however, also one of the most often disputed processes within airlines in order to adequately assign delays or flight cancellations to technical reasons. How can Heads of Engineering properly manage this? 

Airline Technical dispatch reliability is measured based on the utilization of aircraft and the individual delay and cancellation events that can be attributed due to technical reasons. The reason identifications used are the IATA delay code’s and those categorized as technical reasons are:

41 (TD): Aircraft defects
42 (TM): Scheduled maintenance, late release
43 (TN): Non-scheduled maintenance, special checks and / or additional works beyond normal maintenance
44 (TS): Spares and maintenance equipment, lack of or breakdown
45 (TA): AOG (Aircraft on ground for technical reasons) Spares, to be carried to another station
46 (TC): Aircraft change for technical reasons
47 (TL): Standby aircraft, lack of planned standby aircraft for technical reasons
48 (TV): Scheduled cabin configuration and version adjustment

Aircraft utilization is typically tracked in the flight operations software in the form of each sector flown by the aircraft. As a last-minute resort, the actual aircraft flight logbook can be used to retrieve this data. Delay & cancellation assignments can be recorded in various different ways and include digital recording in the flight operations system, recording in the MRO software or paper-based delay reports.

Within Avilytics all this information is automatically collated and visualized in an easy manner. Allowing quick selection over customized periods of time, comparison between periods as well as fleet or individual aircraft selections and comparison between fleets or aircraft.

Dispatch Reliability Avilytics









Interactive dashboarding allow to select, deselect or filter information and drilldown from the overall technical dispatch reliability to the individual delay events that occurred.

Additionally, a separate workspace for technical delays allows to deep dive in the individual delay events itself in order to analyse potential trends based on aircraft systems or seasonal correlation between delays occurring.

Technical delays Avilytics









How to handle assignment of technical delay codes?

One of the most re-occurring issues faced by Heads of Engineering is the assignment of delays to a technical reason, however the actual delay event itself not being technical of nature at all. Delay code assignment is often done in the middle of the heat by flight operations and as soon as an engineer is in the vicinity of the delayed aircraft it is assigned as a technical delay cause, however the actual nature might be a complete different one.

Tip:        For every real technical delay event there must also be a record in the aircraft technical logbook.

Afterall, a technical delay will have required an engineer to perform an activity on the aircraft, which must always be recorded in the aircraft technical logbook. Cross matching your airline technical delay events with entries in the aircraft technical logbook will allow you to filter out any delay or cancellation events that potentially might not have been due to a technical reason.

How to handle data collection and accuracy?

With aircraft utilization and delay or cancellation events often being recorded in different places or systems it is important to properly collect and harmonize these datasets in order to produce accurate and meaningful insights. This can often result in misaligned data and a manual process by reliability engineers to collect all required data in excel and perform manual editing on the data.

Tip:        Ensure an automatic data feed to a centralized system to have unambiguous data.

Automatically feeding data from the flight operations system and from your system to track delay’s & cancellations will ensure that data and insights are available in real-time and will not require manual intervention. It also increases your data quality and subsequent decision-making process as a standardized form of data is used. Such an example includes the industry standard SPEC2000 chapter 11, which is a widely adoption standard for reliability data formats.

Do you have any questions?

Feel free to contact us or give us a call on +31 20 8200 7600. We would be happy to help you further. 


AVILYTICS is a fully out-of-the-box aircraft reliability management solution that focuses on providing insights in technical reliability, upcoming potential technical failures as well as organizational efficiency analytics. It combines the traditional scope of aircraft and fleet reliability management with advanced techniques from predictive analytics to also build AOG risk profiles of aircraft, identify aircraft based reoccurring defects and measure organization performance. A full holistic approach to using data in order to increase aircraft availability and fleet performance.