UA.V.F.K3: Techniques to mitigate mechanical failures of all elements used in sUAS operations such as the battery

ACS Area V — Operations Task F: Maintenance and Inspection Procedures References: A-7

Key Concepts

Build a Maintenance Program That Prevents Failures

• Know your duty: §107.15 requires the remote PICRemote Pilot in CommandCloseThe certificated remote pilot responsible for the Part 107 operation. to check the small unmanned aircraft prior to each flight to determine whether it is in a condition for safe operation. Maintenance includes scheduled and unscheduled overhaul, repair, inspection, modification, replacement, and system software upgrades for the aircraft and its components necessary for flight. When possible, maintain in accordance with the manufacturer’s instructions; if none exist, the operator may develop a maintenance program and schedule. Manufacturers may specify time-in-service limits by flight hours, cycles, and/or calendar-days—adhere to them to extend safe service life. If the manufacturer provides no schedule, establish one yourself. Recordkeeping offers benefits in tracking maintenance and reliability over time. ^[3]
• Use qualified people and parts: Prefer the manufacturer or recommended personnel; if not available, use maintenance personnel familiar with the specific small UASSmall Unmanned Aircraft SystemCloseA small drone plus the control and communication links used to operate it. and components. If you cannot restore a component to safe operational specification through repair, modification, or overhaul, replace it with one in a condition for safe operation. Complete all required maintenance before each flight, preferably per the manufacturer’s instructions or known industry best practices. ^[2]

Practical implication: Treat high-failure items (e.g., power system components like batteries, propulsion, and control links) as “components necessary for flight.” Track cycles and calendar limits, follow the maker’s instructions, and proactively replace parts that can’t be returned to specification. This reduces in-flight power loss, motor stoppage, and control anomalies. ^{[3] [2]}

Execute a Preflight Inspection That Catches Problems Early

• The remote PICRemote Pilot in CommandCloseThe certificated remote pilot responsible for the Part 107 operation. must inspect the small UASSmall Unmanned Aircraft SystemCloseA small drone plus the control and communication links used to operate it. prior to each flight to ensure it is in a condition for safe operation, examining for equipment damage or malfunctions. Conduct the preflight in accordance with the manufacturer’s inspection procedures (owner or maintenance manual) or an owner/operator-developed procedure. Consider creating a scalable inspection program tailored to your aircraft. ^[2]

Practical implication: Use a written preflight checklist that includes airframe integrity, control surfaces/propellers, antennas/connectors, firmware status, and power system health. If any item fails inspection and can’t be restored to safe specification, do not fly—replace the component. ^[2]

Maintain OOP Compliance Items That Affect Safety Margins

• Category 2 aircraft must be labeled to indicate eligibility, and the label must be in English, legible, prominent, and permanently affixed. Category 2 also requires the aircraft be designed/produced/modified so it will not cause injury equivalent to or greater than 11 foot-pounds of kinetic energy, lacks exposed rotating parts that would lacerate skin, and contains no safety defects. The applicant must provide remote pilot operating instructions including a system description, system limitations, allowed modifications that do not change category eligibility, and instructions to verify/change modes or configurations. ^[4]
• If a Category 2 or 3 label is damaged, destroyed, or missing, the remote PICRemote Pilot in CommandCloseThe certificated remote pilot responsible for the Part 107 operation. must re-label in English so it is legible, prominent, and will remain on the aircraft for the duration of the operation before conducting operations over human beings, and the label must correctly identify the eligible category(ies). ^[1]
• For operations over people, the remote pilot is responsible for determining the aircraft’s correct category, verifying proper labeling and listing on an FAAFederal Aviation AdministrationCloseThe U.S. aviation regulator responsible for Part 107 rules, airspace, and pilot certification processes.-accepted Declaration of Compliance, and performing all recommended preflight actions. At night, categories and restrictions for operations over people do not change; manufacturers may need to consider the mass of an anti-collision light when declaring Category 2 or 3 eligibility. Operations must still meet §§ 107.29 and 107.39. ^[5]

Practical implication: Attachments and configuration changes (e.g., lights, payload mounts) can affect safety performance and eligibility. Use the manufacturer’s instructions to verify the correct mode/configuration before flight and keep labels serviceable, which supports both compliance and risk mitigation. ^{[4] [1] [5]}

Preserve Reliability for Category 4 (Airworthiness-Certificated) Aircraft

• For Category 4, the aircraft must have an airworthiness certificate under part 21 and be operated per all operating limitations specified by the Administrator. Sustained flight over open-air assemblies is prohibited unless the operation meets § 89.110 or § 89.115(a). ^[1]
• To preserve continued airworthiness and a reliability level acceptable for flying over people, Category 4 aircraft must have maintenance, preventive maintenance, or alterations performed using the methods, techniques, and practices in the manufacturer’s current maintenance manual or Instructions for Continued Airworthiness, or other methods acceptable to the Administrator. Inspections must follow the manufacturer’s instructions or other instructions acceptable to the Administrator, and parts quality must ensure the aircraft remains in a condition for safe operation. ^[7]

Practical implication: Treat Cat 4 aircraft like certificated systems—follow the ICAInstructions for Continued AirworthinessCloseManufacturer instructions for maintaining an aircraft or component in airworthy condition. and use approved-quality parts. Deviations from prescribed methods or inferior parts increase mechanical failure risk and can invalidate eligibility to operate over people. ^[7]