Sky DutyOne disclaimer first: this guide is an overview to get you oriented, not a regulatory ruling. Whether a given operation needs a Part 135 certificate, and exactly what a certificate authorizes, are determinations for the FAA and, for an operator, for your Flight Standards office or principal operations inspector (POI). Use this to ask better questions and to know what to look up — not to decide a specific case.
The short definition
A Part 135 certificate — issued under 14 CFR Part 119, which sets the certification requirements for air carriers and commercial operators — is the FAA authorization to conduct operations under 14 CFR Part 135, the rules for commuter and on-demand flying. In plain terms, it is the certificate a charter or air-taxi business holds so it can legally carry passengers or cargo for hire on demand. It is not a rating a pilot earns; it is an operating certificate held by the business, issued together with operations specifications (OpSpecs) that spell out exactly what that operator is authorized to do — which aircraft, which kinds of operations, which areas, and under which conditions.
That distinction matters. A Part 135 certificate is granted to an organization with the people, aircraft, manuals, and programs to run a supervised commercial operation — not to an individual pilot the way a commercial or ATP certificate is. For a fuller picture of how Part 135 sits next to the other rulebooks, see Part 91 vs Part 135.
Who needs a Part 135 certificate
Broadly, a business needs a Part 135 certificate when it carries passengers or cargo for compensation or hire in on-demand or commuter operations that amount to common carriage — the charter and air-taxi world. If you are holding out to the public to fly people or freight for money on demand, that is the flying Part 135 is built for.
The line between private flying and flying that requires a certificate is one of the genuinely nuanced areas of the regulations. It turns on concepts like "holding out," common versus private carriage, and who holds operational control, and small changes in the facts can change the answer. This is exactly the kind of question to take to the FAA and your Flight Standards office before the flying starts, rather than settle from an article. The cost of guessing wrong is high, and the determination is fact-specific.
The Part 135 certificate types
The FAA scales Part 135 certification to the size and complexity of the operation. It commonly recognizes four kinds of Part 135 certificate, from the smallest single-pilot operation up to a full standard operation. The exact limits and authorizations for any operator live in that operator's OpSpecs and can differ from the general picture below, so treat these as orientation and confirm the specifics with the FAA.
Single-pilot. A single-pilot certificate authorizes one pilot — the certificate holder — as the only pilot for all Part 135 operations, named in the OpSpecs. It is the lightest-weight form of certificate, with the fewest organizational requirements.
Single pilot in command (single PIC). A single-PIC certificate authorizes one pilot in command plus a limited number of second-in-command pilots, again named in the OpSpecs, and comes with limits on aircraft size, areas of operation, and the kinds of instrument approaches that may be flown.
Basic. A basic certificate is limited in the size and scope of the operation — capped numbers of pilots, aircraft, and aircraft types, with limits on aircraft size and areas of operation. Basic operators are required to develop and maintain manuals and training programs and to designate the required management personnel.
Standard. A standard certificate has no pre-set caps on the size or scope of the operation. The operator must apply for, qualify for, and be granted authorization through OpSpecs for each type of operation it wants to conduct, and it carries the full set of manual, training, and management requirements.
How a Part 135 certificate is issued
Getting a Part 135 certificate is a structured FAA process, not a form you file. The FAA describes it as a phased process with gates between the phases — every item in a phase has to be complete before the applicant moves on. At a high level, the phases run:
- Pre-application — the prospective operator makes first contact and establishes eligibility and intent with the FAA office.
- Formal application — the applicant submits the formal application and the required documents, and meets with the certification team.
- Design assessment — the FAA reviews the applicant's manuals, programs, and other documents in depth for compliance with the regulations.
- Performance assessment — the applicant demonstrates that its procedures and programs work in practice, and the FAA inspects and observes the operation.
- Administrative functions — the FAA issues the certificate and the operations specifications, completing the process.
In practice this takes time and preparation, and many new operators work with an aviation attorney or a certification consultant to build the manuals and programs the FAA will review. The steps above are a map of the process, not a checklist to certify from — the FAA's guidance and your certification team are the authority on what your application needs.
What changes once you hold one
Holding a Part 135 certificate means running a more structured, more supervised operation than a Part 91 flight department. A few things change at once.
Operational control. The certificate holder retains operational control of, and is accountable for, every flight conducted under the certificate, which drives more deliberate dispatch, release, and record practices.
Management and crew. Beyond the smallest single-pilot operations, Part 135 operators designate required management personnel — commonly a Director of Operations, a Chief Pilot, and a Director of Maintenance — and crews face recurrent testing and checks.
Maintenance. Part 135 operators generally follow an approved aircraft inspection program with more formal recordkeeping, rather than relying solely on the annual and 100-hour cycle a Part 91 operator might use.
Duty and rest. Part 135 has its own flight-time, duty, and rest limits in Subpart F. To be precise about a common mix-up: those are not the Part 117 rules, which apply to Part 121 air carriers, not to Part 135. Keeping a clean record of who was on duty and how much they flew is a different job from computing whether a crew member is legal — the record is something a tool can keep; the legality determination stays with the operator.
Where Sky Duty fits
Sky Duty does not certificate anyone and is not a compliance or legality calculator. What it is, for a certificated operator, is the operational backbone: the flight department software that keeps the schedule, the logbook, maintenance status, and trip costs referencing the same records. If you are specifically evaluating Part 135 software for the day-to-day operation around your certificate, that overview shows how crew assignment, duty and flight-time tracking, maintenance visibility, and invoicing fit into one offline-first app.
One boundary worth restating: Sky Duty tracks duty periods and flight time, but it does not compute Part 135 or Part 117 duty-time legality, and it is not an EFB. It keeps the record; interpreting that record against the rules that apply to your certificate stays with you.
