Maintenance intervals for a small commercial drone fleet
One aircraft is easy to maintain. You know roughly how much it has flown, you notice when the props look tired, and you send it in when it starts acting strangely. Three or four aircraft, a dozen batteries and a bag of spare propellers are a different job. Each item keeps its own time, and none of them will tell you that time is up until something goes wrong.
This article covers what the rule asks of you, where the intervals actually come from, and how to run them across a small fleet so nothing comes due on the morning of a job.
What Part 107 asks of you
Part 107 has no maintenance schedule and no maintenance-log requirement. What it has is § 107.15: before each flight, the remote pilot must check the aircraft to determine whether it is in a condition for safe operation. That is a preflight duty, not a schedule.
The FAA's guidance on how to meet it is Advisory Circular 107-2A, chapter 7, and it points straight at the manufacturer. The manufacturer "may identify components of the small UAS that should undergo scheduled periodic maintenance or replacement based on time-in-service limits (such as flight hours, cycles, and/or the calendar-days)", and "operators should adhere to the manufacturer's recommended schedule". Where the manufacturer gives you nothing, the operator "should establish a scheduled maintenance protocol": record every repair and replacement with the component's time in service, and over time "establish a reliable maintenance schedule" from what the record shows. (FAA AC 107-2A, §§ 7.2.1–7.2.1.1.)
So the schedule is the manufacturer's when one exists, and yours to build when it does not. Either way it runs on the same few clocks.
Where the numbers come from
Take one current enterprise airframe as a worked example. DJI's maintenance manual for the Matrice 350 RTK (the revision on DJI's download page, dated August 2025) sets out three levels of regular maintenance:
| Level | Comes due at | What it covers |
|---|---|---|
| Basic | 150 flight hours, or 6 months in use | Regular maintenance items, updates and calibration, deep cleaning |
| Standard | 300 flight hours, or 12 months | All of the above, plus replacing components worn in use |
| Premium | 900 flight hours, or 36 months | All of the above, plus replacing core components |
The same manual gives some components clocks of their own:
- Propellers: replace them after 300 flight hours or one year, and immediately on visible deformation, severe wear, nicks or cracks.
- Batteries (TB65): maintenance every 100 cycles, after more than six months idle, or when the app prompts. Each battery is rated for 400 cycles, and the manual says to replace it after that.
- Vision system: calibrate it at 200 hours of total flight time, or when the app prompts.
(DJI Matrice 350 RTK Maintenance Manual.)
Now compare DJI's first published maintenance program, from 2020, built for the Matrice 200 series and the Mavic 2 Enterprise. That program put the first service at 200 hours or 6 months, the next at 400 hours or 12 months, and motor replacement at 600 hours or 18 months, with "the first to occur triggering the need for a maintenance check". (DJI Enterprise, May 2020.)
The point is not which numbers are right. It is that they differ from one model and one manual revision to the next. A fleet with two models runs two schedules, and a schedule copied from a forum post, or from last generation's manual, is somebody else's schedule.
Two clocks per airframe, and whichever comes first
Every level above is set as hours or months. That "or" is what catches a fleet out, because the aircraft that flies the least is not the one that is safest from the schedule.
Here is an illustration with the Matrice 350 basic level of 150 hours or 6 months, across three aircraft that start the year freshly serviced:
| Aircraft | Flying per month | Basic level comes due | Reached by |
|---|---|---|---|
| A, the workhorse | 30 hours | Month 5, at 150 hours | Hours |
| B, the second ship | 10 hours | Month 6, at 60 hours | Calendar |
| C, the spare | 2 hours | Month 6, at 12 hours | Calendar |
The workhorse reaches its hours first. The other two reach the calendar with most of their hours unused, and the spare reaches it having barely flown. If you track only hours, B and C look fine on paper for years. If you track only the calendar, A runs well past its hours before anyone notices.
So track both, per airframe, and treat whichever comes first as the due date.
Batteries and props keep their own time
Batteries do not belong to an aircraft. They rotate through whichever airframe is flying that day, so a battery's cycle count has nothing to do with any one aircraft's hours. On a fleet, battery maintenance has to be tracked per battery, by serial number:
- Cycles toward the next maintenance (every 100, in the Matrice 350 manual).
- Cycles toward retirement (400 for the TB65).
- Time sitting idle. The battery in the back of the case that nobody picks comes due on the calendar, not on cycles.
The FAA's own maintenance best practices name two battery warning signs worth writing down when you see them: a distorted, bulging casing, and diminishing flight time, which "may indicate impending failure due to exhausted service life". (AC 107-2A, Appendix C.) A note that says "pack 7, two minutes short again" is how you spot the trend before the pack quits in the air.
Propellers are cheaper but work the same way. A set has hours and an age, and it can move between aircraft. When a set goes on, write down which set went on which airframe.
Running it across a fleet
A schedule on paper is not yet a plan. Four habits turn one into the other.
- One list, every due date. For each airframe: hours since the last service level, months since, and the next level due. For each battery: cycles, last maintenance, and days since last use. For each prop set: hours and install date. If it lives in three places, it will be out of date in two of them.
- Look ahead, not back. The useful question is not "what is overdue?" but "what comes due in the next 30 days?" That gives you time to book the service around the work.
- Stagger the fleet. If every aircraft was bought in the same month, every aircraft reaches its calendar limit in the same month. Bring one in early and spread the due dates out, so the fleet never loses two aircraft at once.
- Plan the downtime. The Matrice 350 manual recommends factory or authorized-agent service at every level, which means the aircraft is gone for a while. A due date is also the day you are flying one aircraft short. Plan the spare around it.
None of this needs an elaborate system. It needs the hours, the cycles and the dates, recorded as you fly, in one place.
The record is the schedule
AC 107-2A ends its maintenance chapter on recordkeeping, and its reasoning holds for any fleet: for operators who "rapidly accumulate flight operational hours/cycles", a maintenance record "may provide an essential safety support", and it is how you track "component service life". (AC 107-2A, § 7.3.5.)
It is also the record an insurer asks for when something goes wrong. SkyWatch, a drone insurer, lists "maintenance history" among what every claim needs. (SkyWatch on record-keeping.)
You can build the maintenance schedule from a flight log, but not from memory. The hours come from the flights, the cycles from the batteries, and the dates from the calendar. Keep all three, and the next due date is never a surprise.
Tobren Operations is being built around this record: the flight log, the aircraft and battery history and the crew behind them, in one place. It is not for sale yet. If you want to know when it is, the Operations page will take your email.