Technical Log (Tech Log)

The technical log is the operational bridge between flying and maintenance. Where the permanent airframe, engine and propeller logbooks are the historical archive, the tech log is the live document: it travels with the aircraft and records what has happened since the last maintenance action.

A tech log system typically has two halves. The **journey record** captures each sector — date, crew, departure and arrival, times against the Hobbs or flight-time reference, landings, fuel uplift and consumption. The **technical record** captures the aircraft's condition — defects raised by the crew, the maintenance action taken or the deferral applied, and the certificate of release to service that permits further flight.

Its function is narrower and sharper than the archive's. Before flight, the commander checks the tech log to confirm the aircraft is serviceable, that a valid release is in place, and that any carried defect is properly deferred and its conditions understood. That check is a legal precondition of the flight, not a courtesy. After flight, the commander records the times and enters any new defect. The maintenance organisation reads the same document to know what needs attention and to certify the work.

**Terminology and obligation vary by regulatory regime, and the difference matters.** Under EASA rules, commercial air transport and Part-ML or Part-M managed operations use an aircraft technical log system whose form and content are prescribed, including the deferred-defect record and the release-to-service entry. In the FAA system there is no universal equivalent: 14 CFR 91.417 requires maintenance records be kept, and 91.405 obliges the operator to ensure maintenance record entries are made, but a formal on-board technical log is a feature of operations under Parts 121 and 135 rather than a general Part 91 requirement. Many US flight schools operate a squawk sheet or discrepancy log that performs the same practical role without the regulatory framing.

The failure mode is consistent across regimes. When the flying record and the technical record are kept in different places, a defect entered at the aircraft does not reliably reach the maintenance organisation, and an aircraft with an open squawk stays on the schedule. The tech log exists precisely to make that impossible by putting both records in one document that the next commander must read.

For a school, the tech log's value is that it forces a single point of truth at the aircraft. A student or instructor who reports a defect verbally at the desk has created no record; one who writes it in the tech log has created an obligation that follows the aircraft.

The practical difficulty is completeness. Tech logs fail through omission rather than error — a defect not written down, times not entered, a page not carried forward. Every gap is invisible at the moment it is created and expensive when discovered, because reconstructing hours or a defect history after the fact is guesswork that an auditor will treat as such.

The second consideration is the handoff to billing and maintenance forecasting. The times recorded in the tech log are the same times that drive invoicing and inspection countdowns, so a school transcribing them by hand into two other systems has created two opportunities for the three figures to disagree.

Aviatize keeps flight records, defect reports and maintenance status on one system, so a squawk raised against an aircraft is visible to maintenance and reflected in that aircraft's availability rather than depending on a paper page reaching the right desk. Recorded flight time feeds billing and the maintenance counters from the same entry, instead of being transcribed into separate systems that can then disagree.

Defect reporting and maintenance execution are both available from the mobile app, so a report can be raised at the aircraft and a technician can record time, parts and tools against the resulting work from a tablet. Document management is compatible with both FAA and EASA requirements, with separate document libraries, which matters because what a technical log must contain differs between the two regimes.