Previous-tacho pre-fill

What it is

When you open the Log Flight screen for a fresh session, the Start meter value is pre-filled with the highest end reading logged on that aircraft by a booking that had started by the time yours did, counting your own booking’s earlier legs, and never below the opening reading the aircraft was set up with. The flights it reads are the ones already on your phone, so the moment you save a first leg the second starts from its end reading, even offline and before the aircraft’s own reading has caught up. For a flight you are logging now, this is the aircraft’s current meter reading. It is an ordinary editable value, not a greyed suggestion: tapping into the field keeps it and puts the cursor at the right-hand end, ready for you to correct a digit. You can always edit it; the value you submit is what gets saved.

The End meter field is pre-filled too, with the Start reading less its last digit: a Start of 1803.5 gives an End of 1803, and a round Start of 1234.0 gives 123, so the pre-fill always sits just below the Start. It is an ordinary editable value, not a greyed suggestion: tapping into the field keeps it and puts the cursor at the right-hand end, ready for you to type the last digit or two. Nobody writes down a whole meter reading, and an empty End box invites a partial one — “3.5” where the meter says 1803.5. Starting from the Start reading means the leading digits are already right.

The pre-fill sits below the Start on purpose. A form saved with it untouched would have recorded a flight of no hours, and a meter reading is a money record; sitting below the Start, it is refused by the “End must be above Start” rule until you have typed the real figure. The charge preview waits for it too: until you type an End reading or step it with the + and − controls, the preview stays empty, exactly as it does while any other input it needs is missing, even where the syndicate bills on block or airborne time rather than the meter. The hours read-out beneath it shows a dash until End is above Start, then the hours the two readings describe. That figure is the check on your own entry: you know how long you were out, so a read-out that disagrees says the End reading is wrong. See Usage log fields for the read-out and the two controls beside it.

A “tacho” (short for tachometer, sometimes spelled “tach”) is an hour meter that accumulates engine or propeller running time. The same pre-fill mechanism applies whatever the syndicate has labelled its engine meter: Hobbs, Tacho, or custom.

Who can use it

Everyone logging a flight. The pre-fill is automatic; there is no toggle and no permission gate.

Where to find it

Log Flight screen: the Start field on a new (not editing) log.
Route: /bookings/:bookingId → Log Flight button.

Fields / options

Not a field in its own right. It affects one value on the form:

Field	Pre-filled from	Editable
Start reading (“Tacho Start” by default, or your syndicate’s name for it)	The highest end reading logged on the aircraft by a booking that started no later than yours, never below the aircraft’s opening reading	Yes, always
End reading (“Tacho End” by default, or your syndicate’s name for it)	The Start reading, less its last digit	Yes, always

Behaviour rules

Pre-fill only, never authoritative. The value is a suggestion. You can edit it freely and the edited value is what gets saved.
End starts just below Start, never equal to it or ahead of it. The pre-fill adds no assumed flight time and never claims a duration you have not stated; and because it sits below the Start, the form cannot be saved with it untouched. An End equal to Start is refused too, with its own message (“the meter has not moved”): two identical readings describe no flight, and saving them would leave the aircraft’s meter where it was and the next pilot’s Start pre-fill behind the real reading.
Both meter fields keep their value when you tap them. On the Log Flight screen the Start and End pre-fills are real values, not greyed suggestions. Tapping in puts the cursor after the last digit so you can backspace over the tail; tap a second time to put the cursor wherever you want it.
The plus and minus under End correct it without retyping. Each tap moves the End reading by 0.1, and the hours read-out between them follows. Minus stops once the hours reach zero rather than pushing End below Start. Both controls are inactive until there is a Start reading to measure from, so on a form still waiting for the aircraft’s reading to arrive there is nothing to tap.
The Start follows the aircraft until you touch it. The aircraft’s reading and its logged flights reach your phone separately, so the Start can change a moment after the form opens, when the second of them arrives. It only changes while it is still exactly as the app filled it: once you tap into it or type a reading, it stays as you left it. It also stops changing once you tap into the End or give an End reading, so the hours you are checking cannot shift under you. The End pre-fill follows the Start until you touch the End.
One repeat rule applies throughout the flight history. Within each booking, a later-written log is passed over if its flight times overlap an earlier log, or both start and end readings match within 0.01 h. This is the same rule used for departure pre-fill and server continuity checks. Meter ranges that only partly overlap at different times remain separate flights. Passing over a repeat does not delete it or change what an admin can bill.
A second leg starts where the first ended. Log two flights on one booking and the second opens at the first one’s End reading, not at the reading before your booking and not at the previous booking’s end.
A flight logged late starts from the reading before it. Logging a flight after later bookings on the aircraft have been logged, the Start is the highest reading logged by bookings that started no later than yours, not the reading those later flights have taken the aircraft to. If a flight in an earlier booking has not reached your phone yet, the Start can still be behind; check it against the meter as always.
A draft keeps a Start you gave it, not one the app filled in. A form restored from a draft keeps a Start you typed or read from a photo, whatever has been logged since. A Start the app filled in and you left alone is not saved in the draft, so reopening it fills the Start again from what has reached your phone since; once you have given an End, though, the Start is saved with it, so reopening the draft gives you back the pair you left.
Asset-scoped. The value comes from the asset the booking is for. Different aircraft have independent meter readings.
Includes ground runs and ferry flights, and nothing cancelled. Whatever booking a reading was logged against counts, so a ground run or ferry flight logged during maintenance moves the Start like any other flight and the next pilot is lined up with the real reading. A log on a cancelled or rejected booking does not count, and neither does an End of zero (a syndicate that records block times only stores zero). The highest reading wins, not the most recent log’s: a log entered late, for a flight that happened before one already recorded, does not pull the Start backwards. On an aircraft with nothing logged yet, the Start is the opening reading, and if your phone does not have that either, the aircraft’s stored meter reading. While the app is still reading the flights on your phone, or if it cannot, the Start shows the aircraft’s stored meter reading instead.
Only when the engine meter is captured. Pre-fill applies when the syndicate’s captured measures include the engine meter. A syndicate capturing only block time or airborne time has no Start meter field and no pre-fill.
Only on create. Editing an existing log reads the log’s own saved Start value; it does not re-apply pre-fill.
No photo gate. You do not have to attach a photo to confirm the pre-filled value, and a photo does not validate the value either. See Hobbs photos.
A line says when your Start differs. In Log Flight, once the readings logged before yours are known, a Start that is not where the flight before it ended gets a line under it: “Last flight ended at 1234.5”, naming the highest end reading logged before yours (an earlier leg of your booking included), or “The aircraft’s opening reading is 1234.5” when the applicable opening reading is higher or there is no earlier logged reading. An admin correction can raise that opening reading above older flight logs; the suggestion and finalisation check both use it as a minimum, so no flights are needed to bridge the jump. The line mirrors the “Last landed at” line under the departure. Unlike that line, it also shows when you edit a flight already saved: the edited flight is measured against the flights before it, leaving out the flight itself and its booking’s later legs, so you can see what a corrected log should start on.
A mismatch holds the booking. A Start that disagrees with the higher of the previous genuine flight’s End and the applicable opening reading, above or below it, prevents automatic finalisation and the pilot’s close; an admin can still finalise individually. If an intervening booking has no usage, matching the latest genuine reading (or opening reading) passes, while a differing reading waits for missing usage without a meter-conflict alert. New alerts between bookings wait for ten quiet minutes after the last relevant log change reaches the server, then normally arrive on the half-hourly sweep. Conflicts within a booking and genuine first-flight opening-reading conflicts remain immediate. Correcting the logs withdraws a standing alert immediately. See Tacho-continuity conflict for the full rules.
Quick Capture uses the same logged reading as Log Flight. The “I’m flying now” flow seeds its ramp Start field from the latest eligible flight on your phone, including the previous leg of your booking. It waits for the local flight history, so a delayed aircraft meter update does not pull it back to an older reading. With no logged reading it uses the aircraft’s opening or stored meter reading. The suggestion follows arriving logs until you tap the field. It shows greyed until then; tapping keeps the reading and turns it into an ordinary value you can edit. Leave it alone and it is submitted as it is. Clear it deliberately and it stays clear.
The Apple Watch uses that same Start reading. The paired phone sends the watch the highest eligible end reading for the booking, including earlier legs of that booking, with the same opening-reading floor and exclusions. It waits for the initial history read before offering a meter capture; if the read fails, it uses the stored meter. The suggestion can update until you begin capture. From then on, phone updates keep your confirmed readings unchanged, and the Crown lets you correct the Start. See Capture a flight on your watch.
Saving stops the form’s follow-on hints. While the close-booking sheet is open, the saved flight may already be in your phone’s history. The form does not compare its Start with its own newly saved End, or its departure with its own arrival. The server still checks continuity when you close the booking.
The departure is pre-filled in a similar way. On an aircraft, a new flight’s departure starts at where the aircraft last landed, so a second leg leaves from where the first arrived. See Departure pre-fill.