Avionics Editing and Proofreading Services

The autopilot disconnects itself twice a month, always in cruise, never when a technician is watching. Each time, the shop runs its standard tests, finds nothing wrong, writes "no fault found, system tested satisfactory, returned to service," and reinstalls the same unit. Six months and four "no fault found" reports later, nobody has asked the one question that might actually matter: whether the fault only appears above a certain altitude, a certain temperature, or after a certain number of flight hours since the last power cycle — because no report has ever recorded the conditions under which it did not occur, only that it didn't occur during the test.

We edit what avionics technicians and repair stations produce — no fault found and troubleshooting reports, return-to-service statements and release documentation, interference and intermittent fault write-ups, software and configuration change records, bench test and ground test documentation, and the correspondence sent to an operator about a recurring, unresolved fault. Our editors work on the report written after a fault that refuses to reappear on command.

The conditions under which testing occurred is what turns a "no fault found" report into useful evidence rather than a dead end, and its failure is a report that records the test performed without recording what it could not replicate. Tested satisfactory says the unit worked during the test; it says nothing about whether the test resembled the conditions that produced the fault. We work through these so the conditions of the original fault — altitude, phase of flight, temperature, elapsed time since power-up — are recorded precisely from the pilot report and compared against the conditions the bench test could actually achieve, since a ground test at ambient temperature cannot rule out a fault that only appears at cruise altitude after two hours aloft; so every prior occurrence of the same fault on the same unit is referenced, given that four "no fault found" reports on the same component are a pattern of intermittent behaviour, not four unrelated non-events; so what was actually checked is itemised rather than summarised as "system tested," because a reader six months later needs to know whether wiring, connectors and software configuration were checked or only the unit itself; so a report distinguishes "fault not present during test" from "fault does not exist," as these are different claims and only the first one is actually supported by a ground test; so where a fault cannot be replicated on the ground, that limitation is stated plainly rather than absorbed into a satisfactory result; and so a recommendation for what would actually catch an intermittent fault — a flight test, a data logger, extended monitoring — is given rather than simply reinstalling the same unit again. Reports written this way eventually find the fault instead of returning it to service four more times.

Everything you send is treated in confidence, including fault histories, technical data and correspondence with operators or manufacturers. We are editors rather than licensed avionics technicians or engineers, and we offer no view on fault diagnosis or airworthiness. What we can do is make sure the report says exactly what was and was not established.