Category 4 Operations
Category 4 is structurally different from every other category in 14 CFR Part 107 Subpart D: instead of a weight test or a declaration-of-compliance impact-energy test, it requires the aircraft itself to hold a standard FAA airworthiness certificate, the same fundamental type of certification process used for manned aircraft. This lesson covers the requirements of 14 CFR 107.140: the airworthiness-certificate pathway, the requirement to operate strictly within the approved Flight Manual's limitations, and the ongoing maintenance obligations that come with holding this certificate.
A fundamentally different qualification path: the airworthiness certificate
Categories 1, 2, and 3 all rely on either a straightforward physical test (Category 1's weight and rotating-parts test) or a manufacturer-obtained declaration of compliance following impact-energy testing (Categories 2 and 3). Category 4 uses neither. Under 14 CFR 107.140(b), a Category 4 aircraft must have an airworthiness certificate issued under 14 CFR Part 21 — the same general certification framework the FAA uses for manned aircraft types. This is a substantially more involved process than filing a declaration of compliance, generally reserved for larger, more capable, or more specialized unmanned aircraft where the manufacturer has pursued full FAA type certification or an equivalent airworthiness approval.
Operating strictly within the approved Flight Manual
Holding an airworthiness certificate is not the end of the Category 4 requirement. Under 107.140(a) and (b)(2), the remote pilot in command must operate the aircraft in accordance with all operating limitations specified in its approved Flight Manual, and that Flight Manual must not prohibit operations over human beings. In effect, the FAA has shifted the specific safety boundaries for a Category 4 aircraft into the aircraft's own certified Flight Manual, rather than into a single fixed regulatory number the way Categories 1, 2, and 3 use a weight or injury-energy threshold. A remote pilot flying a Category 4 aircraft needs to know that specific aircraft's approved limitations, not a single number that applies across every Category 4 aircraft.
Sustained flight over open-air assemblies still requires Remote ID compliance
Like Category 1 and Category 2, a Category 4 aircraft may not conduct sustained flight over an open-air assembly of human beings unless the operation also complies with 14 CFR 89.110 (Standard Remote ID) or 89.115(a) (a Remote ID broadcast module operated within visual line of sight). Category 4 is not exempt from this condition simply because it holds the FAA's most rigorous certification — the Remote ID condition for open-air assemblies applies across Categories 1, 2, and 4 alike, with only Category 3 treating open-air assemblies as an outright prohibition instead.
Ongoing maintenance obligations under 107.140(c)
Because a Category 4 aircraft holds a genuine airworthiness certificate, it carries genuine airworthiness-style maintenance obligations, not the lighter general maintenance expectations that apply to most Part 107 aircraft. Under 107.140(c), the aircraft's owner or operator must ensure that maintenance is performed by personnel following guidance acceptable to the FAA, with the necessary skills and equipment, using parts that maintain the aircraft's certificated condition, and that comprehensive records are kept — including a description of the work performed, the date, who performed it, the status of any life-limited parts, and compliance with any applicable airworthiness directives. These records must be retained for at least one year after the work is completed, transfer with the aircraft if ownership changes, and remain available for FAA or NTSB inspection. Complying with the maintenance program requirements of 14 CFR Part 43 and Part 91 Subpart E satisfies these obligations.
- Qualified personnel: Maintenance performed per FAA-acceptable guidance, by personnel with the necessary skills and equipment.
- Recordkeeping: Work description, date, performer, life-limited parts status, and airworthiness directive compliance, retained at least one year and transferred with ownership.
Category 4: the airworthiness-certificate pathway, Flight Manual operating limitations, and ongoing maintenance recordkeeping.
View LargerScenario: a package-delivery operator using a type-certificated aircraft
A delivery company operates a specialized unmanned aircraft that holds a standard FAA airworthiness certificate issued under Part 21, and its approved Flight Manual permits operations over human beings subject to specific altitude and route limitations. The remote pilot in command reviews the Flight Manual before every route change to confirm the planned delivery path stays within those approved limitations, and the company's maintenance program follows Part 43-equivalent recordkeeping, tracking every inspection and part replacement with retained records. Because delivery routes regularly cross over urban sidewalks with individual pedestrians, but rarely hover over a dense outdoor crowd, the aircraft typically does not trigger the sustained-flight-over-open-air-assembly Remote ID condition — but the operator has confirmed the aircraft is Standard Remote ID-equipped regardless, since routes occasionally pass near public gathering spaces during events.
Category Classifier Helper
Confirming Category 4 eligibility before a job
Category 4 verification centers on paperwork the aircraft's owner/operator maintains, not a field measurement the pilot performs.
Confirm the specific aircraft holds a current standard airworthiness certificate
Verify the certificate was issued under 14 CFR Part 21 for this specific aircraft, not just a general model claim from the manufacturer.
Review the approved Flight Manual's operating limitations
Read the specific limitations that apply to this aircraft, and confirm the Flight Manual does not prohibit operations over human beings for the planned mission profile.
Confirm maintenance records are current
Check that required maintenance has been performed and documented per 107.140(c), including any applicable airworthiness directive compliance and life-limited parts tracking.
Check the flight path for sustained flight over an open-air assembly
If the mission involves hovering or repeated passes over a dense, stationary crowd, confirm Remote ID compliance under 14 CFR 89.110 or 89.115(a) before conducting that portion of the flight.
| Mistake | Why it happens | Correct understanding | Regulation / source |
|---|---|---|---|
| Confusing an airworthiness certificate with a declaration of compliance | Both are forms of FAA acceptance associated with a category of Subpart D, inviting the two to blur together | A declaration of compliance (Categories 2 and 3) is based on impact-energy testing; an airworthiness certificate (Category 4) is issued under Part 21, a substantially more involved certification process similar to manned aircraft | 14 CFR 107.140(b)(1); 14 CFR 107.115(a)(2) |
| Assuming any large or heavy drone can simply "become" Category 4 with enough paperwork | Category 4 is sometimes described informally as the option for heavier aircraft, without emphasizing the certification burden involved | Category 4 requires the aircraft to actually hold a Part 21 airworthiness certificate, a rigorous process the aircraft's manufacturer must pursue, not something arranged for a single flight | 14 CFR 107.140(b)(1) |
| Believing Category 4's certification removes all further restrictions on flying over people | Holding the FAA's most rigorous airworthiness certification feels like it should be the final word on safety | The aircraft must still be operated within its approved Flight Manual's limitations, and sustained flight over an open-air assembly still requires Remote ID compliance under 89.110 or 89.115(a) | 14 CFR 107.140(a), (b)(2) |
| Treating Category 4 maintenance the same as ordinary Part 107 preflight inspection expectations | Most Part 107 aircraft only need reasonable preflight checks, not formal certificated maintenance | Category 4 aircraft require certificated-style maintenance under 107.140(c), including qualified personnel, retained records, and airworthiness directive compliance | 14 CFR 107.140(c) |
What makes Category 4 different from Categories 2 and 3?
Categories 2 and 3 rely on a manufacturer-obtained declaration of compliance following an impact-energy test. Category 4 instead requires the aircraft to hold a standard FAA airworthiness certificate issued under 14 CFR Part 21, the same general certification framework used for manned aircraft.
Does Category 4 have a fixed weight or injury-energy limit like the other categories?
No. Category 4 has no fixed regulatory number of that kind. Instead, the specific limitations come from that aircraft's own approved Flight Manual, which must not prohibit operations over human beings.
Can a Category 4 aircraft hover over a crowd without any additional requirement?
No. Sustained flight over an open-air assembly still requires Remote ID compliance under 14 CFR 89.110 or 89.115(a), the same condition that applies to Category 1 and Category 2 aircraft.
Test Your Knowledge
Answer the questions below to check your understanding. Every answer can be found in the lesson above.