The aircraft technical log, often referred to as the tech log or logbook, is an indispensable and non-negotiable document in aviation. It serves as a primary source of technical and operational data for each flight, logging details about the aircraft, flight, and any defects or maintenance actions taken and will be referenced for various purposes.

What Data Does Aircraft Tech Log Cover?

The tech log is a crucial tool used daily by pilots and maintenance engineers and part of the regular oversight of an aircraft. It is important to note that the format and consequently information included varies between countries and operators. Information covered could include:

• Aircraft & Operator Details

  Includes the operator's name, PIC (Pilot in Command) details, aircraft type and model, registration number, and flight number.

• Route Flown & Transit Checks

  Includes departure and arrival airports and any transit checks performed.

• Aircraft Hours and Cycles

  Includes block time, time in service, total cycles accumulated, total cycles carried forward from the previous page, APU hours and cycles, total accumulated cycles thus far, and hours remaining until the next inspection.

• Defect, Malfunction, and Maintenance Actions

  Includes defects or malfunctions, maintenance actions taken, return to service approval, and maintenance checks performed

• Oil, Fuel, and Hydraulics

  Includes fuel uplift and quantity, oil levels and the amount topped up in the engines and APU, and hydraulic top-ups.

• Engine Flight Records

  Includes start and takeoff EGT, autoland uses, etc.

• Component Replacement Record

  Includes part description, part and serial number of the on and off part, and tag number.

How Does Data From The Aircraft Tech Log Impact Various Functions?

As illustrated above, the tech log is integral to the aircraft's maintenance and flight activity records. This historical record is crucial as the data from the tech log is subsequently used for various purposes, here are some examples of how tech log data is utilized:

Flight Hours & Flight Cycles Calculation – The tech log records flight cycles and hours, often with a separate section for APU hours and cycles. This information is essential for calculating the aircraft’s remaining cycles before the next inspection, scheduled maintenance, or other necessary work. It is crucial for maintenance planning and component changes, particularly for LLPs and those requiring HT calculations, thus also directly impacting the aircraft's airworthiness.

Component Reliability Considerations for Engineering – Data from the aircraft tech log is one of many sources used to identify reliability issues and manage maintenance more strategically. Engineering teams use various data points from the tech log, such as noted discrepancies, maintenance actions taken, flight hours and cycles, and component replacement records, to identify repetitive incidents, frequent component defects, or recurring replacements that can signal problems. Component change periods are evaluated against established Mean Time Between Unscheduled Removals (MTBUR) rates, and lower-than-expected rates prompt further investigation and corrective actions. This data is crucial for ensuring aircraft reliability and strategic maintenance management.

Pilot Hours & Payroll – Operations teams use tech log data to calculate pilot flying hours, as it contains precise block times for each flight. This data would later be used to arrange rest hours for the pilot and as a reference to calculate payroll accurately.

Common Record Findings in Aircraft Tech Logs

• Missing Pages, Stamps, and Critical Information

  Sequenced page numbers are crucial for maintaining accurate total hours. Missing pages necessitate a search for Dirty Finger Print and hard copies or a statement from operators if said hard copies cannot be recovered. The absence of stamps and related critical information would also be flagged, requiring immediate action.

  
  

• Utilization Recording Discrepancies

  Missing or uncorrected utilization recordings compromise the historical accuracy of the tech log, enabling traceability of component changes and maintenance records.

  
  

• Incomplete Material Documentation and Certification

  The tech log includes records of component replacements, which come with necessary certifications such as the Authorized Release Certificate, Certificate of Conformity, Material Certification Form, Non-Incident Statement (LLPs), and Serviceable Tag. These documents provide essential information, including TSO/TSN, modification history (especially ADs and SBs), and recent test results, crucial to ensure timely maintenance and inspections.

In summary, the tech log provides a detailed historical account of flight hours, utilization, maintenance activities, and other critical details said data is vital for various purposes and departments, from payroll, maintenance planning, to reliability. Complete and accurate records are vital for airworthiness and asset redelivery, as they influence the aircraft's value and are part of leasing agreements. Incomplete documentation can lead to prolonged redelivery periods and increased costs for operators who need to address them. 

Need support for your records?

Comprehensive and accurate records management demands meticulous attention and in-depth knowledge of the field. It involves not just the maintenance of records but also the ability to interpret and utilize this information to make informed decisions and maintain the highest standards of safety and performance.

That is why many lessors, airlines, and asset management firms have entrusted technical partners like TBM Aviation to ensure their asset records are complete, accurate, and fully traceable, supporting both safety and asset value. Contact our team at info@tbmaviation.com to discuss your records needs and how we can best support you.