14 CFR Part 29 Certification

14 CFR Part 29 is the regulation that establishes the airworthiness standards for transport-category rotorcraft — the larger, multi-engine helicopters used in commercial passenger transport, heavy-lift operations, offshore energy, and emergency medical services. It's the rotorcraft equivalent of Part 25 for transport-category airplanes, and like Part 27 for normal-category rotorcraft, it carries powerplant and drivetrain requirements that have no fixed-wing parallel.

The same principle that distinguishes rotorcraft from fixed-wing propulsion applies here: the engine doesn't produce thrust directly. It drives a transmission and rotor system, and the mechanical chain between engine and rotor is a substantial, safety-critical system in its own right. On transport-category rotorcraft, the demands on that drivetrain are heavier — higher power, greater loads, more complex transmission architectures, and more stringent redundancy and reliability requirements than normal-category machines. Part 29 reflects that.

What Part 29 Covers

Part 29 sets the standards a transport-category rotorcraft must meet to be airworthy. In scope it spans the entire aircraft — structural strength, flight characteristics, systems and equipment, and the requirements that protect the people aboard. The transport-category designation brings additional rigor across all of these, reflecting the higher-consequence operating environment.

The powerplant installation portion of Part 29 is broad, covering how the engine and all associated systems are installed and integrated into the rotorcraft. That includes the engine installation itself, fuel and oil systems, engine controls and instruments, exhaust systems, fire protection, cooling, and the drive and transmission systems that transfer engine power to the main and tail rotors.

On a transport-category rotorcraft, those systems are typically more complex than their Part 27 equivalents. Multi-engine configurations, combining gearboxes, more elaborate oil and lubrication systems, and the redundancy requirements that come with carrying passengers in a transport-category aircraft all add to the certification scope. The substantiation bar is higher because the consequences of failure are higher.

The Part 29 / Part 33 Division

The same installation-versus-engine distinction that applies across all of propulsion certification applies here.

Part 33 is the engine. The engine's design, performance, durability, and the test program that proves it — that's Part 33. The engine earns its own type certificate against those standards, regardless of what it's installed in.

Part 29 is the installation and the drivetrain. Once that engine goes into a transport-category rotorcraft, Part 29 governs how it's installed and how the power it produces gets to the rotor. The full scope of powerplant installation requirements applies — from the engine mount to fire protection to the transmission — and each of those systems has its own substantiation demands distinct from the engine's Part 33 certification.

The interaction between Part 29 and Part 33 is particularly relevant on transport-category rotorcraft because these aircraft typically run turboshaft engines at higher power settings, with more demanding duty cycles, and with transmission systems that have to handle that power reliably across the operating envelope. Work that touches the powerplant on a Part 29 rotorcraft almost always has to account for both regulations.

How Part 29 Connects to PMA

For most manufacturers, the practical encounter with Part 29 isn't certifying a new transport-category rotorcraft — it's PMA work on components that go into the powerplant installation of rotorcraft already in service.

A Parts Manufacturer Approval for a component in any of these systems still has to show that the part meets the applicable airworthiness standards — and for a transport-category rotorcraft, those standards live in Part 29. Whether the compliance path is identicality or test and computations, the substantiation has to close against the relevant Part 29 requirements.

Transport-category rotorcraft present a particularly strong PMA opportunity in the drivetrain and transmission space. These are high-value, maintenance-intensive components on aircraft with demanding operating profiles — offshore helicopters, EMS aircraft, heavy-lift machines. The platforms stay in service for decades, the components are expensive, and operators are accustomed to sourcing approved alternatives where they're available. Transmission hardware, drive system components, fuel and oil system parts, and engine installation fittings on platforms like these are exactly the kind of high-demand, high-value articles where a PMA alternative finds immediate buyer interest.

Where Prime Propulsion Fits

Our in-house DER holds Part 29 delegation specifically scoped to engine installations, fuel and oil systems, and drive and transmission systems — the propulsion and drivetrain core of the transport-category rotorcraft powerplant. Those are the areas where we can review and approve the engineering data in your PMA submission via Form 8110-3.

That delegation scope covers much of where transport-category rotorcraft PMA demand actually concentrates. The higher power, higher complexity, and higher maintenance demands of transport-category drivetrain and transmission components make them natural PMA candidates — they're expensive, they're critical, and operators need reliable supply. Scoping which Part 29 requirements apply to a given component, and how they interact with Part 33 on the engine side, is the kind of work that goes more efficiently with someone who's done it before.

If you have a transport-category rotorcraft component in any of those areas and want to talk through whether it's a viable PMA candidate, contact us — there's no cost to scope it out. You can also learn more about our FAA PMA certification services.

Prime Propulsion delivers expert FAA certification solutions for small to medium-sized aerospace firms. Our DER-led team specializes in PMA, STC, Test Cell Correlations, and Repair Specification support.