When a helicopter picks up an HVAC unit and sets it on a rooftop, strings conductor between transmission towers, drags a seismic line, or hoists a longline load into a job site, it is not flying charter and it is not flying under a generic commercial rule. It is conducting a rotorcraft external-load operation under 14 CFR Part 133, a distinct operating certificate with its own certification, personnel, equipment, and operating rules — separate from a Part 135 charter certificate and from a Part 137 agricultural certificate.
Part 133 is lighter on the kind of voluminous maintenance-program recordkeeping that defines larger Part 135 maintenance operations, but it is exacting about a small, specific set of compliance objects: who may hold the certificate, what the rotorcraft and attaching means must be approved under, what each load class permits, and a handful of documents — an approved flight manual, a competency record per pilot, Class D training currency — that an inspector expects to be current and producible. Get those right and the rest of Part 133 is operating discipline.
This guide walks the certificate (§133.11, §133.17), the four load classes from §1.1, the operating limitations (§133.45), the personnel and training rules (§133.37), and the records to keep — and clears up several section numbers operators routinely misremember.
What Part 133 Covers — and Who Is Exempt
Part 133 prescribes airworthiness certification rules for rotorcraft used in, and operating and certification rules governing the conduct of, rotorcraft external-load operations in the United States (§133.1). An external load is defined in §1.1 as a load that is carried, or extends, outside of the aircraft fuselage — and the external-load attaching means is the structural components used to attach that load to the aircraft. The certificate requirement is in §133.11: no person subject to the part may conduct these operations within the United States without, or in violation of the terms of, a Rotorcraft External-Load Operator Certificate issued under §133.17, and may not conduct them under a business name not on the certificate.
§133.1(c) — Five categories exempt from the certification rules
- Rotorcraft manufacturers when developing external-load attaching means;
- Rotorcraft manufacturers demonstrating compliance of equipment utilized under this part or the appropriate portions of Part 27 or 29;
- Operations conducted by a person demonstrating compliance for the issuance of a certificate or authorization;
- Training flights conducted in preparation for the demonstration of compliance with this part; and
- A Federal, State, or local government conducting operations with public aircraft.
Note also that §133.1 excepts aircraft subject to Part 107 (small unmanned aircraft). Public-aircraft external-load work — a government agency lifting with its own aircraft — falls outside the certification rules but, like all public-aircraft operations, carries its own status questions; this guide addresses civil commercial operations.
Part 133 is its own certificate — not a flavor of Part 135 or Part 137
External-load work is not charter and not aerial application. The certificates, the certification gates, and the records are different. An operator that does longline construction and flies charter would hold both a Part 133 certificate and a Part 135 certificate and keep both record sets — including, on the Part 135 side, the Part 135 pilot records and a documented operational-control structure. Mixing the regimes in one filing cabinet is a classic source of "we thought that was covered" gaps.
The Four Rotorcraft-Load Combination Classes — 14 CFR §1.1
Almost everything else in Part 133 — the flight checks, the operating limitations, the flight-manual contents, the placards, the crew training — flows from the class of rotorcraft-load combination you are approved to fly. The four classes are defined not inside Part 133 but in the general definitions section, 14 CFR §1.1, where a rotorcraft-load combination is the combination of a rotorcraft and an external load, including the external-load attaching means.
Class A rotorcraft-load combination
The external load cannot move freely, cannot be jettisoned, and does not extend below the landing gear.
A fixed tank or rigidly attached equipment that stays put and tucks above the gear.
Class B rotorcraft-load combination
The external load is jettisonable and is lifted free of land or water during the rotorcraft operation.
The classic longline lift — a sling load carried clear of the ground, releasable in an emergency.
Class C rotorcraft-load combination
The external load is jettisonable and remains in contact with land or water during the rotorcraft operation.
Wire-stringing, cable-laying, or dragging operations where the load stays in contact with the surface.
Class D rotorcraft-load combination
The external load is other than a Class A, B, or C and has been specifically approved by the Administrator for that operation.
Human external-load (hoist/personnel) work — the only class in which a non-essential person may be carried (§133.1(d)).
Class D is the people class — and it is strictly controlled
§133.1(d) provides that, for the purpose of Part 133, a person other than a crewmember or a person who is essential and directly connected with the external-load operation may be carried only in approved Class D rotorcraft-load combinations. In other words, human external-load operations live in Class D, and they carry the heaviest operating limitations in the part (see §133.45 below). The class your combination is approved for is stated on a cockpit/cabin placard under §133.49(a) and recorded in the approved flight manual under §133.47 — both of which are documents an inspector will want to see.
Not sure whether your operator certificate, approved flight manual, and per-pilot competency records would survive a §133.39 inspection? Run the free readiness check and see what is missing before the FAA does.
The Operator Certificate — Issuance, Duration, and Carriage
Subpart B (§§133.11–133.27) is the certification spine. Three sections matter most for compliance recordkeeping: how you qualify (§133.17 and §133.21), how long the certificate lasts (§133.13), and where it has to be (§133.27).
§133.17 / §133.21 — Issuance and the Chief Pilot
§133.17 sets the requirements for issuance of the certificate. §133.21 (Personnel) requires the applicant to hold, or have available the services of at least one person who holds, a current commercial or airline transport pilot certificate with a rating appropriate for the rotorcraft prescribed in §133.19. The applicant must designate one pilot — who may be the applicant — as chief pilot for external-load operations, and may designate qualified assistant chief pilots; each must be acceptable to the Administrator and hold a current Commercial or ATP certificate with the appropriate rating. A change in chief or assistant chief pilot must be reported immediately, and §133.21(c) gives a 30-day window to designate and qualify a new chief pilot before operations must stop.
§133.13 — Duration (the 24-month clock)
Unless sooner surrendered, suspended, or revoked, the certificate expires at the end of the twenty-fourth month after the month in which it is issued or renewed. This is a renewal cycle, not a perpetual authorization — and §133.15 covers application for issuance or renewal. An external-load operator that lets the certificate lapse is operating without authorization, which is exactly the kind of avoidable gap a tracked expiration date prevents. The same logic that governs an airman medical expiration applies to the operator certificate itself.
§133.27 — Availability, Transfer, and Surrender
The holder must keep the certificate and a list of authorized rotorcraft at the home base of operations and make them available for inspection by the Administrator on request, and must carry a facsimile of the certificate in each rotorcraft used in the operation. The certificate is not transferable; if the FAA suspends or revokes it, the holder must return it; and if operations cease and are not resumed within two years, the holder must return the certificate to the responsible Flight Standards office. This pairs naturally with the aircraft's own ARROW documents and Part 47 registration records.
Knowledge and skill: §133.23 (and the §133.23(d) waiver)
§133.23 requires the applicant (or the chief pilot) to demonstrate knowledge and skill to the Administrator. The knowledge test covers pre-operation steps and area survey, loading and rigging methods, rotorcraft performance under the approved procedures, instructing flight crew and ground workers, and the contents of the Rotorcraft-Load Combination Flight Manual. The skill test covers maneuvers appropriate to each load class — takeoffs and landings, directional control while hovering, acceleration from hover, flight at operational airspeeds, approaches, maneuvering the load to release position, and winch operation if installed. Per §133.23(d), the Administrator may waive the tests where previous experience and safety record in external-load operations show adequate knowledge and skill. Keep the dated record of this demonstration — it underlies the §133.37(a) competency requirement for every pilot.
Operating Limitations — 14 CFR §133.45 (and the Class D Rules)
§133.45 sets the operating limitations that must be established in the Rotorcraft-Load Combination Flight Manual. The weight, center-of-gravity, and airspeed limits are anchored to the airworthiness demonstrations in §133.41 and §133.43, and they are the operational expression of those structural and flight-characteristics limits.
| §133.45 limitation | What it establishes |
|---|---|
| (a) | Weight and center-of-gravity limits established under §133.43(c) |
| (b) | A maximum external load weight that may not exceed the weight used in showing compliance with §§133.41 and 133.43 |
| (c) | Airspeed limitations established under §133.41 |
| (d) | Restricted-category rotorcraft may not operate over a densely populated area, in a congested airway, or near a busy airport where passenger transport is conducted |
| (e) | Class D operating requirements (see below) — type certification, intercom, personnel device, and dual-action emergency release |
Class D personnel operations carry the heaviest limitations (§133.45(e))
Because a Class D combination can carry a person as the external load, §133.45(e) layers on additional requirements before such operations may be conducted. In broad terms it requires that the rotorcraft be type-certificated in the transport category with the relevant single-engine hover capability, that there be direct radio intercommunication among required crewmembers, that an FAA-approved personnel-lifting device be used, and that the device have an emergency release requiring two distinct actions. These are the safeguards that distinguish a human external-load operation from a cargo lift.
The exact §133.45(e) text is detailed and equipment-specific; always work from the current regulation and your FAA-approved flight manual for the precise conditions. The compliance-records point is that a Class D approval generates equipment, device-approval, and crew-intercom documentation that an inspector may ask to see.
Two more operating-rules points are worth holding onto, both from §133.33 (Operating rules). First, §133.33(a) makes it a violation to conduct an external-load operation without, or contrary to, the Rotorcraft-Load Combination Flight Manual — the manual is binding, not advisory. Second, before operating a rotorcraft-load combination that is substantially different from any combination previously operated, §133.33(c) requires conducting an operational flight check confirming load handling, controllability on initial liftoff and in hover, acceleration and forward-flight behavior, load oscillation, and a safe airspeed for the operation. And §133.33(f) prohibits external-load operations under IFR unless specifically approved by the Administrator.
The flight manual and the placards are records, too (§133.47, §133.49)
§133.47 requires the applicant to prepare and submit the Rotorcraft-Load Combination Flight Manual for the Administrator's approval, containing the operating limitations and procedures established under Subpart D, the class(es) for which airworthiness was demonstrated, and an information section that includes precautionary advice about static-electricity discharge for Class B, Class C, and Class D combinations. §133.49 requires a cockpit/cabin placard stating the approved class and the occupancy limitation, and a placard, marking, or instruction near the attaching means stating the §133.45(b) maximum external load. The approved flight manual is one of the first documents an inspector asks for — keeping the current approved version filed and producible is a recordkeeping obligation, parallel to how a fixed-wing operator manages an AFM and its supplements.
Personnel, Carriage of Persons, and Training — §§133.35, 133.37
Part 133 controls who may be aboard during an external-load operation and what each pilot and crewmember must have demonstrated. These are the records most likely to be incomplete in a real review, because they live in personnel files rather than on a load ticket.
§133.35 — Carriage of Persons
Under §133.35(a), no certificate holder may allow a person to be carried during external-load operations unless that person is a flight crewmember, a flight crewmember trainee, performs an essential function in connection with the operation, or is necessary to accomplish the work activity directly associated with it.
§133.35(b) requires the pilot in command to ensure all persons are briefed before takeoff on the pertinent normal, abnormal, and emergency procedures and the equipment to be used. (Carrying a non-essential person as the load itself is the separate Class D case under §133.1(d).)
§133.37 — Training, Currency, and Testing
Per §133.37(a), no certificate holder may use, and no person may serve as, a pilot unless that person has demonstrated the §133.23 knowledge and skill and has in personal possession a letter of competency or an appropriate logbook entry.
§133.37(b) adds a Class D layer: no certificate holder may use, and no person may serve as, a crewmember or other operations personnel in Class D operations unless, within the preceding 12 calendar months, that person has completed an approved initial or recurrent training program.
The competency record per pilot is the field most likely to go missing
The §133.37(a)(2) letter of competency (or the equivalent logbook entry) is a per-pilot, per-combination credential — and like a Part 135 line check, it is the kind of record that is easy to fly on and hard to produce on demand. For Class D operators, the §133.37(b) 12-calendar-month training currency is a recurring expiration that behaves exactly like other recurrent-training deadlines. The same discipline that governs Part 135 pilot records and Part 135 training-program records applies here: prove each airman is qualified for the class flown, and date it. The contrast with broader Part 135 flight-time and duty/rest recordkeeping is instructive — Part 133 asks for fewer records, but the few it asks for are unforgiving.
The Records to Keep — and the §133.39 Inspection Authority
Part 133 does not contain a single consolidated "records" section the way Part 137 does at §137.71. Instead the records are distributed across the certification and operating rules, and the obligation to produce them is anchored in §133.39 (Inspection authority): each person conducting an operation under Part 133 shall allow the Administrator to make any inspections or tests he considers necessary to determine compliance with the Federal Aviation Regulations and the Rotorcraft External-Load Operator Certificate. Here is the practical compliance set an external-load operator should be able to put a hand on.
| Compliance object | Where it lives | Reference |
|---|---|---|
| Operator certificate + list of authorized rotorcraft | Home base of operations; facsimile in each rotorcraft | §133.27 |
| FAA-approved Rotorcraft-Load Combination Flight Manual | For each class flown; the binding operating document | §133.47, §133.33(a) |
| Pilot letter of competency / logbook entry | Each external-load pilot, per combination | §133.37(a)(2), §133.23 |
| Class D crew/operations training records | Initial or recurrent within preceding 12 calendar months | §133.37(b) |
| Chief / assistant chief pilot designation | On file; changes reported, 30-day re-designation window | §133.21 |
| Operational flight-check record (new/changed combination) | Before substantially different combinations are flown | §133.33(c) |
| Aircraft airworthiness evidence (attaching means, quick-release) | Aircraft maintenance records; approval basis | §133.43, §43.9 / §43.11 |
The airworthiness layer deserves a word. §133.43 requires the external-load attaching means and the quick-release device to be approved under a specific basis (Part 27 or 29, the historical Part 8/Part 133 paths, or §21.25), and §133.51 governs the airworthiness certification of the rotorcraft for external-load operations. The maintenance actions that install and maintain that equipment are documented like any other civil-aircraft maintenance — through §43.9 maintenance-record entries (with inspection entries under §43.11), and the airframe runs on the same Part 91 aircraft-records and airworthiness-directive compliance obligations as any other helicopter. Part 133 sits on top of that airworthiness foundation; it does not replace it.
Section numbers operators misremember
The certificate-required rule is §133.11, issuance is §133.17, and duration is §133.13 — they are not the same section. The certificate-carriage rule is §133.27 (Availability, transfer, and surrender), not §133.21 (which is Personnel). The four load classes are defined in §1.1, not inside Part 133 — and §133.43 ends at its weight-and-CG subsection, with no separate class-definition subsection. Operating rules are §133.33; operating limitations are §133.45. Cite the right section and you save yourself an argument with an inspector.
Staying Audit-Ready — Where a Compliance Document Layer Fits
Part 133 recordkeeping is small in volume but unforgiving in specifics: a two-year certificate, an approved flight manual per class, a competency record per pilot, and a 12-calendar-month training currency for Class D crew. The risk is not that the records are voluminous — it is that they are scattered across a home-base file, aircraft document pouches, pilot folders, and a maintenance-tracking system, and that no single place shows whether the certificate is current, the flight manual is the approved version, and every external-load pilot's competency record is on file before the Administrator exercises the §133.39 inspection authority.
Keep your Part 133 records searchable, current, and audit-ready
FileFlo is a compliance document intelligence platform — a read-only proof layer. It does not fly external loads, run your operation, replace your chief pilot, or perform any FAA-required maintenance or operational-control function. It organizes the documents that prove Part 133 compliance:
- Classifies each uploaded record against the governing reference — the operator certificate and authorized-rotorcraft list (§133.27), the FAA-approved Rotorcraft-Load Combination Flight Manual (§133.47), each pilot's §133.23 letter of competency or logbook entry (§133.37(a)), and Class D training records (§133.37(b))
- Indexes records so the certificate, flight manual, competency records, and training currency are retrievable in one place when an inspector asks
- Tracks the §133.13 24-month certificate renewal and the §133.37(b) 12-calendar-month recurrent-training currency as expiring dates
- Assembles an audit-ready binder if the Administrator exercises the §133.39 inspection authority — organized by compliance object
FileFlo sits alongside your operation and your Flight Standards relationship — it does not replace your chief pilot, your A&P/IA, or your principal operations inspector. It keeps the documents that prove your compliance audit-ready. Starter $89/mo · Professional $299/mo · 5-day free trial, no credit card required.
If you also fly charter, conduct helicopter air-ambulance (HEMS) work, or operate under Part 91K fractional rules, the same proof layer covers those adjacent regimes — and the broader aviation records retention schedule — without forcing your Part 133 external-load documents into a system built for a different certificate. For the operating side of a charter certificate, see how a Part 135 surveillance audit runs.
Frequently Asked Questions
What is a Rotorcraft External-Load Operator Certificate, and who needs one?
Under 14 CFR Part 133, no person subject to the part may conduct rotorcraft external-load operations within the United States without, or in violation of the terms of, a Rotorcraft External-Load Operator Certificate issued by the Administrator under §133.17 (§133.11(a)). An external-load operation means lifting or carrying a load that is outside the fuselage — longline construction lifts, logging, powerline and wire stringing, seismic and fire work, and helicopter hoist or personnel work. §133.1(c) exempts five narrow categories from the certification rules (rotorcraft manufacturers developing or demonstrating attaching means, persons demonstrating compliance for a certificate or authorization, training flights in preparation for that demonstration, and Federal, State, or local governments operating public aircraft). Everyone else conducting these operations commercially needs the certificate — and §133.11(b) adds that you may not conduct the operations under a business name that is not on the certificate.
How long is the Part 133 operator certificate valid, and where must it be kept?
Per §133.13, unless sooner surrendered, suspended, or revoked, a Rotorcraft External-Load Operator Certificate expires at the end of the twenty-fourth month after the month in which it is issued or renewed — so it is on a two-year renewal cycle, not a perpetual document. §133.27 governs where it lives: the holder must keep the certificate (and a list of authorized rotorcraft) at the home base of operations and make it available for inspection by the Administrator on request; a facsimile of the certificate must be carried in each rotorcraft used in the operation. The certificate is not transferable, and if the FAA suspends or revokes it the holder must return it. Treating the certificate expiration as a tracked compliance date — the way you would a medical or an inspection due date — is the single cheapest way to avoid an inadvertently lapsed authorization.
What are Class A, B, C, and D rotorcraft-load combinations?
The four classes are defined in 14 CFR §1.1, and they drive almost everything else in Part 133. A Class A rotorcraft-load combination is one in which the external load cannot move freely, cannot be jettisoned, and does not extend below the landing gear. A Class B combination is one in which the external load is jettisonable and is lifted free of land or water during the rotorcraft operation (the classic longline lift). A Class C combination is one in which the external load is jettisonable and remains in contact with land or water during the operation (think wire-stringing or dragging). A Class D combination is one in which the external load is other than a Class A, B, or C and has been specifically approved by the Administrator for that operation — and per §133.1(d), Class D is the only class in which a person who is not a crewmember and not essential and directly connected with the operation may be carried as an external load. Your operating limitations, your flight-manual contents, your placards, and your crew training all flow from which classes your rotorcraft-load combination is approved for.
What does the FAA inspect in a Part 133 operation, and what records prove compliance?
Part 133 is lighter on standing recordkeeping than Part 135, but it is exacting about a handful of compliance objects that must be current and producible. The inspection backbone is §133.39, which provides that each person conducting an operation under the part shall allow the Administrator to make any inspections or tests he considers necessary to determine compliance with the Federal Aviation Regulations and the Rotorcraft External-Load Operator Certificate. In practice that means being able to produce: the operator certificate and the list of authorized rotorcraft kept at home base (§133.27); the facsimile certificate carried in each rotorcraft (§133.27); the FAA-approved Rotorcraft-Load Combination Flight Manual for each class flown (§133.47); each pilot's letter of competency or appropriate logbook entry (§133.37(a)(2)); and, for Class D operations, the within-12-calendar-month initial or recurrent training records for crewmembers and other operations personnel (§133.37(b)). FileFlo organizes exactly these documents so the set is retrievable in one place when the Administrator asks.
Do Part 133 pilots and crew need recurring training, and how is it documented?
It depends on the class. Under §133.37(a), no certificate holder may use, and no person may serve as, a pilot in Part 133 operations unless that person has successfully demonstrated to the Administrator the knowledge and skill of §133.23 for the rotorcraft-load combination, and has in his or her personal possession a letter of competency or an appropriate logbook entry showing it. For Class D operations specifically, §133.37(b) adds a currency layer: no certificate holder may use, and no person may serve as, a crewmember or other operations personnel in Class D operations unless, within the preceding 12 calendar months, that person has completed an approved initial or recurrent training program. So the §133.23 knowledge-and-skill demonstration (documented by a letter of competency or logbook entry) is the baseline for every external-load pilot, and the 12-calendar-month training currency is an added Class D requirement for crew and operations personnel.
What goes in the Rotorcraft-Load Combination Flight Manual, and why does it matter?
The Rotorcraft-Load Combination Flight Manual is the governing operating document, and §133.33(a) makes operating without it, or contrary to it, a violation. §133.47 requires the applicant to prepare the manual and submit it for the Administrator's approval, following the rotorcraft flight manual provisions of Part 27 or Part 29 as applicable. It must contain the operating limitations, normal and emergency procedures, performance, and other information established under Subpart D; the class or classes of rotorcraft-load combination for which airworthiness has been demonstrated; and an information section that includes, among other things, precautionary advice about static-electricity discharge for Class B, Class C, and Class D combinations. The operating limitations in §133.45 (weight, center of gravity, airspeed, and the Class D personnel-lifting requirements) are anchored in this manual — which is why keeping the current approved version available is a recordkeeping obligation, not just a paperwork formality.
How is Part 133 different from a Part 135 charter certificate or Part 137 ag certificate?
They are three distinct operating certificates with different scopes and different records. Part 135 covers commuter and on-demand carriage of persons or property for compensation; Part 137 covers agricultural aircraft operations (dispensing economic poisons, seed, and similar). Part 133 covers rotorcraft external-load operations — lifting and carrying a load outside the fuselage — and it does not authorize the carriage of passengers in the ordinary sense. Under §133.1(d), only an approved Class D combination may carry a person who is not a crewmember and not essential and directly connected with the external-load operation. An operator that does longline construction and also flies charter would hold both a Part 133 certificate and a Part 135 certificate and keep both record sets separately. Conflating the regimes — or filing Part 133 documents in a system built for Part 135 — is a common source of "we thought that was covered" gaps.
How does FileFlo help a Part 133 external-load operator stay audit-ready?
FileFlo is a compliance document intelligence platform — a read-only proof layer. It does not fly external loads, run your operation, replace your chief pilot, or perform any FAA-required maintenance or operational-control function. What it does is organize the documents that prove Part 133 compliance: it classifies each uploaded record against the governing reference (the operator certificate and authorized-rotorcraft list under §133.27, the FAA-approved Rotorcraft-Load Combination Flight Manual under §133.47, each pilot's §133.23 letter of competency or logbook entry under §133.37(a), and the Class D 12-calendar-month training records under §133.37(b)), indexes them so they are retrievable in one place, tracks the §133.13 two-year certificate renewal and the §133.37(b) recurrent-training currency as expiring dates, and assembles an audit-ready binder if the Administrator exercises the §133.39 inspection authority. The operator still owns the operation and the recordkeeping; FileFlo keeps the proof of it searchable, current, and ready to present.
Chad Griffith
Founder, FileFlo — compliance document intelligence
This article is a compliance document perspective, not legal, airworthiness, or flight-operations advice. It explains what 14 CFR Part 133 requires at the certificate and records layer; it is not a substitute for guidance from your Flight Standards office, an aviation attorney, an A&P/IA, or your principal operations inspector on any specific operation. Regulatory citations were checked against the current Code of Federal Regulations; always confirm the live text before acting.
Related Aviation Compliance Guides
Part 137 Agricultural Aircraft Operations
The sister special-operation certificate — crop dusting, aerial seeding, and its records
What Records Must a Part 135 Operator Keep?
The full Part 135 operator record set — distinct from a Part 133 external-load certificate
Part 135 Helicopter Air-Ambulance (HEMS) Records
Another rotorcraft-specific certificate regime and its compliance records
Aircraft Flight Manual & Supplements Records
How an approved flight manual is managed — parallel to the §133.47 combination manual
§43.9 Maintenance Record Entries
How attaching-means and quick-release maintenance is documented
ARROW Documents Explained
The airworthiness and registration documents underneath any external-load rotorcraft
Keep your Part 133 records ready before the Administrator asks
FileFlo classifies your external-load records against 14 CFR Part 133, keeps the operator certificate, approved flight manual, pilot competency records, and Class D training currency retrievable in one place, tracks the 24-month certificate renewal and the 12-month recurrent-training deadline, and assembles an audit-ready binder on demand under the §133.39 inspection authority.
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