Tracked measure
The tracked measure — shown as Counts against on the maintenance forms — is the quantity a usage-based maintenance item is counted on. It answers the question “50 hours of what?”.
It matters because the candidates are not interchangeable. A Hobbs meter runs whenever the engine runs, so it accumulates while you taxi and hold; flying hours accumulate only between wheels-up and wheels-down. Over a year of short flights the two can differ by a substantial margin, so an inspection counted on the wrong one falls due at the wrong time. The measures also sit on unrelated scales: a meter face typically reads in the thousands, while accumulated flying hours start from whatever figure the aircraft carried when it joined, so a due-at value only means anything alongside the measure it belongs to.
There are three measures:
- Flying hours — accumulated time in service, taken from the finest span you record: wheels-up to wheels-down where you record it, otherwise brakes-off to brakes-on. The usual basis for inspections.
- Your engine meter, shown under your own name for it (for example Tacho hours or Hobbs hours) — the meter’s own face reading. The usual basis for engine-life items such as an oil change.
- Landings — the accumulated cycle count, used by cycles-based items and not offered as a choice.
The options offered when creating an item are limited to the measures your syndicate actually records for that aircraft. That is deliberate: an item pegged to something nobody writes down would never accrue, so it would never come due and never ground the aircraft, with nothing on screen to say so. The same limit is applied again when the item is saved, so an item written on a device that was offline cannot slip through against a measure the syndicate stopped recording in the meantime.
Recording a measure is not the same as having a figure for it. Flying hours and landings are counted up from a starting figure, so what is logged in Syndik8 says how much has been added and never what the total is; until somebody states the total, the aircraft shows Not recorded rather than a zero. The engine meter is the exception, because a flight records it as an actual reading off the face, so one logged flight establishes it.
When you pin a check to a measure with no figure, the form asks what that measure reads on the aircraft now and will not save without it. You do not need to work backwards. Giving a reading draws a line: everything flown up to that moment is already inside the figure, including flights entered late, and only flying dated afterwards is added on top. Giving the reading again moves the line. See Correct an aircraft’s meter readings.
The measure is shown wherever an item’s figures appear, so a remaining reading is “12.4 flying hrs” or “12.4 Tacho hrs” rather than an ambiguous “12.4 hrs”.
Unlike the interval type, an admin can change it after the item is created, but not on its own. Because the item’s due-at value is an absolute reading on the old measure’s scale, the edit form also asks what the new measure read at the last completion and works the due-at value out again from that. Until that reading is supplied the change cannot be saved. If the aircraft has no reading at all yet for the new measure, the edit form asks for that too — the same “what does it read now” figure the create form and the template sheet ask for — before the change can be saved. See Maintenance items.