Aircraft Maintenance Tracking: Hours and Calendar, Whichever Comes First
A shared aircraft is grounded by whichever limit it reaches first: the hours since the last 100-hour inspection, or the date of the next annual. Pilot-Next keeps both limits for every aircraft, marks each item Due Soon or Overdue, and forecasts from the club's own bookings in which week the hours will run out — so the inspection can be planned before a member's weekend booking runs into it. Below: the intervals the FAA and EASA rules set, how the two kinds of limit combine, and what other flying club platforms say about maintenance.
No credit card. Maintenance tracking is included in every plan, SOLO too.
Which flying club software tracks aircraft hours and maintenance due?
Pilot-Next tracks both: every aircraft gets maintenance plans with an interval in flight hours, in calendar months or both, and each plan shows OK, Due Soon or Overdue against the aircraft’s Tacho reading and today’s date. For an hours-based item it also forecasts the date the hours will run out, from the aircraft’s own confirmed bookings. Of the platforms we read on their own websites on 28 September 2026 and 30 September 2026, FlightCircle, AircraftClubs, Pilot Partner, Holdshort, Schedule Master, Coflyt, Flyout, FlyClub, Squawkd, Hobbstack, Aviatize, FLYLOG.io and Avibase also say they track maintenance, and FlightCircle, AircraftClubs, Squawkd and Hobbstack also say they forecast the due date. The table below shows what each says about hours, calendar dates, alerts and forecasts.
| Platform | By flight hours | By calendar date | Warns before due | Forecasts the due date | Source |
|---|---|---|---|---|---|
| Pilot-Next | Yes — an interval in flight hours, counted on the Tacho meter | Yes — an interval in calendar months, alone or with hours | Due Soon in the last 10% of the interval, Overdue after it, shown in the app and on the schedule | Yes — the week the hours run out, from confirmed bookings and recent use | this page |
| FlightCircle | Yes — “Meter Based”, “Meter and Time Based” reminders | Yes — “Time Based” and “Calendar date” reminders | “Yellow indicates 10% remaining or less”; e-mail alerts; basic users “prevented from dispatching” with expired reminders | Yes — “existing reservations and averages of time booked vs billed” | flightcircle.com |
| AircraftClubs | Yes — “tachometer and/or time based maintenance items” | Yes — “time based” items | “14-day maintenance item reminders” to the maintenance manager | Yes — “projected based on aircraft usage calculations” | aircraftclubs.com |
| Pilot Partner | Yes — “Hobbs and Tach readings drive … your maintenance due times” | Yes — “Hours or Calendar (whichever first)” | “Due Soon – 25 % or less remaining”; an expired required item shows the aircraft Unairworthy | Not stated | pilotpartner.net |
| Holdshort | Yes — “hobbs/tach time driven” inspections | Yes — “date-based” inspections; annual due dates “calculated per FARs” | Notifications per organisation settings; a due or past-due inspection sets the status to Unairworthy | Not stated | holdshort.com |
| Schedule Master | Yes — “operating time-based maintenance needs” | Yes — “date … based”, “annual inspections” | “Notifications … when maintenance is due or complete” | Not stated | schedulemaster.com |
| Coflyt | Not stated as a standard feature (Enterprise: “custom, operator-defined tracking methods for hours”) | Yes — “VFR/IFR inspections”, “Oil change dates” | Not stated | Not stated | coflyt.com |
| Flyout | Yes — “engine time tracking feed maintenance countdowns” | Not stated | “automatic tracking and alerts” | Not stated | flyout.app |
| FlyClub | Not stated (“upcoming maintenance for each aircraft”) | Not stated for maintenance (expiry reminders for documents) | Not stated | Not stated | flyclub.app |
| Squawkd | Yes — AMP tasks tracked “alongside flight hours and calendar time” | Yes — same; ARC expiry date and days remaining on the dashboard | ARC: amber at 60 days, red at 30; alerts for recurring AD deadlines | Yes — “Analytics and maintenance forecasting” (Pro); basis not stated | squawkd.com |
| Hobbstack | Yes — 100-hour inspections and oil changes “using your actual flight data” | Yes — annual inspections | Colour-coded status board of what is due; automatic reminders for recurring ADs | Yes — from bookings, completion rate and cancellations, as an 80% date range | hobbstack.com |
| Aviatize | Yes — Hobbs hours, flight cycles and up to 5 custom counters | Yes — calendar dates | “Automatic alerts when 100-hour, annual, AD, or Service Bulletin actions come due” | Not stated | aviatize.com |
| FLYLOG.io | Yes — items linked to a TACH, HOBBS or engine-cycle counter | Yes — or to a date; remaining hours or days shown | Reminders based on flight hours or dates; plan visible to all members | Not stated | flylog.io |
| Avibase | Yes — interval in operating hours | Yes — in months, alone or whichever comes first with hours | In the app: “Bald” (soon) and “Fällig” (due), hours or days overdue; threshold not stated | Not stated | avibase.app |
Read on each vendor's own website on 28 September 2026 (the last five on 30 September 2026); quotes are the vendor's own words. “Not stated” means the site does not say — not that the feature does not exist. Prices and the rest of the feature set for twelve platforms are in the flying club software comparison.
Which inspections does a club aircraft have to track?
Under the FAA rules no one may fly an aircraft unless it has had an annual inspection within the preceding 12 calendar months (14 CFR 91.409(a)), and an aircraft that carries passengers for hire or is provided for flight instruction for hire also needs an annual or 100-hour inspection within the preceding 100 hours (91.409(b)). Under EASA Part-ML, a light aeroplane maintained to the minimum inspection programme is inspected every year or every 100 hours, whichever comes first, with a tolerance of one month or 10 hours (ML.A.302(d)). On top of that come calendar items such as the ELT inspection, the transponder test and, for IFR flight, the altimeter and static system test.
| Item | Interval | Applies to | In Pilot-Next | Rule |
|---|---|---|---|---|
| Annual inspection (FAA) | Within the preceding 12 calendar months | Every aircraft operated under Part 91, with exceptions such as special flight permits, experimental and light-sport certificates, and progressive inspection programmes | Interval 12 months | 14 CFR 91.409(a) |
| 100-hour inspection (FAA) | Within the preceding 100 hours of time in service; up to 10 hours more only to reach the place of inspection, counted towards the next 100 | An aircraft carrying anyone other than crew for hire, or provided by the instructor for flight instruction for hire | Interval 100 hours | 14 CFR 91.409(b) |
| Minimum inspection programme (EASA) | Every year or every 100 hours, whichever comes first; tolerance 1 month or 10 hours; the next interval counts from the inspection | Aeroplanes and touring motor gliders under Part-ML (aeroplanes up to 2,730 kg MTOM not on an airline certificate) maintained to the MIP | Interval 100 hours and 12 months | Part-ML ML.A.302(d) |
| Airworthiness review certificate (EASA) | Valid 1 year; may be extended by a year at most twice in a row | Aircraft under Part-ML | Interval 12 months | Part-ML ML.A.902(a) |
| ELT inspection (FAA) | Within 12 calendar months after the last inspection | US-registered aeroplanes that must carry an emergency locator transmitter | Interval 12 months | 14 CFR 91.207(d) |
| Transponder test (FAA) | Within the preceding 24 calendar months | A transponder required by 91.215(a) | Interval 24 months | 14 CFR 91.413 |
| Altimeter and static system test (FAA) | Within the preceding 24 calendar months | Aeroplanes and helicopters flown IFR in controlled airspace | Interval 24 months | 14 CFR 91.411 |
Read in the eCFR and in the consolidated text of Regulation (EU) No 1321/2014 on 28 September 2026. This is a summary of the recurring intervals, not the whole rule: exceptions, the approved maintenance programme of your own aircraft, airworthiness directives and the manufacturer's instructions (engine and propeller overhaul among them) decide what applies to a particular aircraft. What an annual inspection and an engine overhaul reserve add to the cost of a flight hour is worked out per type in the aircraft ownership cost calculator.
How do hours and calendar limits work together?
Whichever comes first. A plan with an interval of 100 hours and 12 months falls due at the Tacho reading or on the date, whichever the aircraft reaches first; a plan with only one interval uses that one. In Pilot-Next an item turns Due Soon in the last 10% of its interval — the last 10 hours of a 100-hour interval, the last 36 days of a 12-month one — and Overdue once the reading or the date is passed. When the work is signed off, the Tacho reading at completion plus the hour interval becomes the next due reading, and the completion date plus the months becomes the next due date.
One maintenance plan, two limits — whichever comes first
Flight hours (Tacho) — interval 100 h
42 hours left OK
Calendar — interval 12 months
30 days left Due Soon
Status of the plan:
Due Soonset by the calendar limit
Two rules count differently from that, and a plan can be corrected by hand for both. Under the FAA 100-hour rule the aircraft may overrun by up to 10 hours only to reach the place of inspection, and those hours count towards the next 100 — so after such a ferry, set the next due Tacho reading back by the hours flown beyond the limit. And a “calendar month” runs to the end of the month, while Pilot-Next counts months from the day of completion: its due date for an annual falls on the same day of the month, which is on the early side of the legal limit.
Pilot-Next counts maintenance hours on the Tacho meter, also for an aircraft that bills on Hobbs time. Hobbs vs Tacho: what counts explains the difference between the two meters and what each is used for.
How does Pilot-Next forecast when the next inspection falls due?
It walks through the aircraft’s confirmed future bookings in order and turns each booked block into expected Tacho time, using the booking pilot’s own ratio of Tacho time to booked time from past flights on that aircraft, blended with the fleet ratio when a pilot has flown it fewer than five times. The booking during which the remaining hours run out is the forecast; if the bookings do not use them up, Pilot-Next extrapolates beyond the last booking at the aircraft’s average daily Tacho use over the last 90 days, or over the last year when it has hardly flown recently. Pilots see the result as the forecast week of the next item on the schedule while they book.
Worked example (illustrative numbers)
A club aircraft has 37.7 Tacho hours left until its 100-hour inspection. The confirmed bookings over the next weeks add up to 30.0 booked hours, and the members who booked them average 0.8 Tacho hours per booked hour, so those bookings are expected to use 24.0 hours. That leaves 13.7 hours. Over the last 90 days the aircraft averaged 0.4 Tacho hours a day, so the remaining hours run out about 35 days after the last booking — and that week is what pilots see on the schedule.
37.7 Tacho hours until the 100-hour inspection
24.0 h — used by confirmed bookings
30 booked hours × 0.8 Tacho hours per booked hour
13.7 h — left after the last booking
at 0.4 Tacho hours a day: due about 35 days after the last booking
Each forecast carries a confidence that follows from how much recent flight data backs it, and the schedule marks the days of the forecast week in the booking calendar. Bookings on an aircraft that is Due Soon or Overdue are not refused automatically: the status is there so that nobody books without seeing it, and the club decides. The same forecast is available to an AI assistant through the Pilot-Next MCP server (tool get_maintenance_forecast): “when is the next 100-hour on PH-ABC due?”
Does maintenance software replace the aircraft’s technical records?
No. Pilot-Next keeps the maintenance plans, each completion with its date, Tacho reading and notes, and the status and forecast that follow from them. The logbooks, the certificate of release to service and, under EASA, the airworthiness review certificate remain the legal records, kept by whoever maintains the aircraft; the software makes sure the group sees in time when the next entry is due.
How much does maintenance tracking cost in Pilot-Next?
Maintenance tracking is part of every plan, including the free one. SOLO is free forever for 1 aircraft and 1 pilot and asks for no payment details; BASIC covers 1 aircraft and 5 pilots for €9 a month, PRO 2 aircraft and 10 pilots for €18 a month, and ULTRA unlimited aircraft and pilots for €45 a month, all billed annually.
Start free on SOLOMaintenance is one part of running a shared aircraft. See also aircraft scheduling software for bookings, Hobbs and Tacho logging and billing, how co-owners split the costs, how to bill pilots for flight time, and how 12 flying club software platforms compare.