A complex aircraft, in FAA terms, is an airplane equipped with three specific mechanical systems: retractable landing gear, flaps, and a controllable-pitch propeller. That’s it. The definition isn’t about size, speed, or how intimidating the cockpit looks. It comes down to those three features, each of which adds a layer of hands-on management the pilot must handle during flight.
The Three Defining Features
Each component in the complex aircraft definition exists because it requires the pilot to make active decisions during different phases of flight, rather than relying on fixed systems that stay in one configuration.
Retractable landing gear means the wheels tuck up into the fuselage or wings after takeoff and extend again before landing. This reduces aerodynamic drag in cruise flight, improving speed and fuel efficiency. But it also introduces the very real possibility of a gear-up landing if the pilot forgets to extend the wheels, which is one of the most common (and expensive) mistakes in general aviation.
Flaps are movable panels on the trailing edge of the wings that increase lift at lower speeds. Nearly all training aircraft have flaps, so their inclusion in the complex definition may seem odd. The distinction is that complex aircraft pair flaps with the other two systems, creating a workload where the pilot manages wing configuration, propeller settings, and gear position simultaneously during approaches and departures.
Controllable-pitch propeller (often called a constant-speed propeller) lets the pilot adjust the blade angle to optimize engine performance at different speeds and altitudes. Think of it like a transmission in a car: low pitch for takeoff power, higher pitch for efficient cruising. In simpler trainers, the propeller is fixed in one position and the pilot never touches it. A constant-speed prop adds a second engine control (the propeller lever, or “blue knob”) alongside the throttle.
More recently, the FAA has recognized that airplanes with a full authority digital engine control (FADEC) system also meet the complex definition, even without a pilot-controlled propeller. FADEC automates engine management electronically, which creates its own set of systems knowledge a pilot needs to master.
How Complex Differs From High Performance
These two categories overlap in practice but are legally separate. Before 1997, the FAA lumped retractable gear, flaps, controllable propellers, and high horsepower into one “high performance” category. That year, the agency split them apart. High performance now refers strictly to any airplane with an engine producing more than 200 horsepower. Complex refers to the three mechanical systems described above, regardless of horsepower.
An airplane can be one, both, or neither. A Cessna 172RG is complex (retractable gear, flaps, constant-speed prop) but produces only 180 horsepower, so it’s not high performance. A Cessna 182 with fixed gear produces 230 horsepower and qualifies as high performance but not complex. A Piper Arrow checks both boxes. Each category requires its own separate endorsement from an instructor.
The Endorsement You Need to Fly One
Under 14 CFR 61.31(e), you cannot act as pilot in command of a complex airplane unless you’ve received ground and flight training from an authorized instructor in a complex airplane (or a simulator representing one) and been found proficient in its operation and systems. The instructor then gives you a one-time logbook endorsement certifying that proficiency. Unlike a flight review, this endorsement doesn’t expire. Once you have it, it’s permanent.
There’s no written test and no practical test with an examiner. Your instructor decides when you’re ready, signs your logbook, and you’re legal. The training typically covers normal and emergency gear operations, constant-speed propeller management, and the additional checklist items that come with these systems.
Common Complex Training Aircraft
A handful of models dominate the complex training world because they’re widely available, relatively affordable to rent, and forgiving enough for pilots transitioning from simpler airplanes.
- Piper Arrow (PA-28R): Probably the most common complex trainer in the country. It’s essentially a Piper Cherokee with retractable gear and a constant-speed prop, so pilots already familiar with the Cherokee family feel at home.
- Cessna 172RG (Cutlass): A retractable-gear version of the ubiquitous Cessna 172. Many flight schools use it specifically because students already know the 172 platform.
- Beechcraft Bonanza: A step up in speed and capability. More commonly used by pilots building complex time after their initial endorsement rather than for the endorsement itself.
- Mooney M20 series: Known for speed and efficiency, Mooneys are complex aircraft with a loyal following, though less common in rental fleets.
- Beechcraft Baron (BE-55): A twin-engine complex aircraft often used for multi-engine training, where students learn to manage complex systems on two engines simultaneously.
Insurance and Practical Requirements
The FAA endorsement is the legal minimum, but insurance companies set their own, often much steeper, requirements. Typical insurance minimums for renting a complex airplane like a Piper Arrow include 100 hours of total pilot-in-command time, 25 hours of complex time, 5 hours in the specific make and model, and a 2-hour dual checkout with an instructor. For a Cessna 172RG at one major flight school, students need 25 hours of complex time and 15 hours in that specific airplane before flying it solo.
These numbers vary by insurance carrier and aircraft owner, but they consistently exceed the FAA’s legal baseline by a wide margin. If you’re planning to rent a complex airplane, expect to invest significantly more time and money than the endorsement alone requires.
Complex Aircraft and the Commercial Certificate
For years, anyone pursuing a commercial pilot certificate with a single-engine airplane rating had to bring a complex or turbine-powered airplane to their practical test (checkride). This made complex time a mandatory part of commercial training, and flight schools built their programs around it.
The FAA changed this policy. Applicants for a commercial pilot certificate with an airplane single-engine rating no longer need to provide a complex or turbine-powered airplane for the practical test. The same change applies to flight instructor certificate applicants. The FAA’s reasoning was straightforward: removing this requirement significantly reduces costs for people pursuing these certificates, since complex airplanes rent for considerably more per hour than standard trainers.
That said, the underlying training requirements haven’t changed. Commercial pilot candidates still need the aeronautical experience specified in 14 CFR 61.129(a)(3)(ii), which includes time in a complex, turbine-powered, or technically advanced airplane. And the complex endorsement under 61.31(e) remains fully in effect. You still need it before you can fly a complex airplane as pilot in command, regardless of what certificate you hold. The change simply means you can take your checkride in a simpler, cheaper airplane and log your complex time separately.
Why the Designation Matters
The complex aircraft category exists because managing retractable gear, a constant-speed propeller, and flaps together represents a genuine increase in cockpit workload. Forgetting to lower the gear costs tens of thousands of dollars in repairs. Mismanaging a constant-speed propeller can damage the engine. Coordinating all three systems during busy phases of flight like approach and landing requires habit patterns that don’t exist in fixed-gear, fixed-pitch airplanes.
For most pilots, the complex endorsement is a stepping stone. It’s often the first time they fly an airplane where forgetting a checklist item has expensive or dangerous consequences, and the systems management skills it builds carry forward into every more capable airplane they fly afterward.