When it comes to aircraft, it’s not easy to know the difference between category, type, and class, especially for those entering the aviation world. The Federal Aviation Administration uses various ways to classify or group machines operated or flown in the air. This rating system of definitions allows the Federal Aviation Administration to group and regulate aircraft for their safe operation. Continue reading to find out more about the classifications and categories of aircraft. 

How To Categorize, Classify, or Identify Aircraft

The ways to rate aircraft are design, airworthiness, and certification. There are several categories of aircraft that can be further classified. The FAA (Federal Aviation Administration) certifies three forms of aircraft: 

1. Aircraft
2. Aircraft engines
3. Propellers

What Is The “Type” Of Aircraft?

The FAA issues a Type Certificate (TC) for the product when they are satisfied it complies with the applicable airworthiness standards. Types of aircraft for certification include:

1. Airplane – An engine-driven, fixed-wing aircraft that is supported in flight by the dynamic reaction of the air against its wings.
2. Rotorcraft – An aircraft that depends on the lift generated by one or more rotors for its support in flight.
3. Lighter Than Air – An aircraft that can rise and remain suspended by using contained gas weighing less than the air displaced by the gas.
4. Glider – A heavier-than-air aircraft that is supported in flight by the dynamic reaction of the air against its lifting surfaces and whose free flight does not depend principally on an engine.
5. Powered Lift – An aircraft capable of vertical takeoff, vertical landing, and low-speed flight that depends on engine-driven lift devices or engine thrust for lift and on non-rotating airfoil(s) for lift during horizontal flight.
6. Powered Parachute – A powered aircraft comprised of a flexible or semi-rigid wing connected to a fuselage so that the wing is not in position for flight until the aircraft is in motion. 
7. Weight-Shift Control – A powered aircraft with a framed pivoting wing and a fuselage controllable only in pitch and roll by the pilot’s ability to change the aircraft’s center of gravity concerning the wing. Flight control of the aircraft depends on the wing’s ability to flexibly deform rather than the use of control surfaces.
8. Rocket – An aircraft propelled by ejected expanding gasses generated in the engine from self-contained propellants and not dependent on the intake of outside substances. 

What Is A “Class” Of Aircraft?

Categories of aircraft are further divided into a class based on design configuration and airworthiness. However, not all categories have a class. Some aircraft are considered “special classes” and do not have their own airworthiness standards, such as gliders, powered lift, and rockets.

What is “Airworthiness”?

Airworthiness refers to an aircraft’s operation qualities and performance in flight. You can identify aircraft according to airworthiness and design configurations such as:

1. Weight
2. Size
3. Engine type 
4. Maximum speed
5. Maximum flight altitude
6. Operational role
7. Range and endurance

Aircraft Certification Classes

Aircraft certification class refers to a broad grouping of aircraft with similar propulsion characteristics, landing, and flight. Examples include rotorcraft, airplanes, balloons, gliders, seaplanes, and land planes.

Airplane Certificate Types

As used in aircraft certification, it refers to airplanes with similar designs. Examples are: 

• G-IV and G-IV-X 
• 737-700 and 73770C
• 1900 and 1900

The 4 airplane classes include:

• Single-engine sea class
• Multi-engine sea class
• Single-engine land class
• Multi-engine land class

What Is The “Category” Of Aircraft?

Different airworthiness standards apply to the different “categories” of aircraft defined by the Code of Federal Regulations (14 CFR) according to the FAA:

1. Utility, Acrobatic, and Commuter Category Airplanes — 14 CFR part 23
2. Transport Category Airplanes —14 CFR part 25
3. Normal Category —14 CFR part 27
4. Transport Category Rotorcraft — 14 CFR part 29
5. Manned Free Balloons — 14 CFR part 31
6. Aircraft Engines — 14 CFR part 33
7. Propellers — 14 CFR part 35

Airplane Categories

Similarly to certification, categories of airplanes are the groupings of airplanes based on the intended use and operating limitations. They include:

1. Transport
2. Utility
3. Normal 
4. Acrobatic
5. Provisional
6. Limited
7. Restricted 

Common Types Of Airplanes 

The airplanes that most people are familiar with are jets and propeller planes, specifically either commercial airliners or military airplanes. 

Jet Engines 

They are well-known because of their speed and power compared to typical aircraft. Jets can achieve maximum efficiency at super speeds and go faster than sound speed up to an altitude of 49,000 feet. They were first developed in England in 1928 but later perfected in Germany in 1936, and are one of the most commonly used aircraft for the commercial and private sectors.

7 Common Types Of Airplanes

There are a number of aircraft in the sky every day, but we’re not always aware of them until we hear the sound of their engines roaring overhead. These are the most common airplanes found in the sky:

1) Jumbo Passengers Jets

The first wide-body commercial jet to earn the Jumbo Jet name was the Boeing 747. Boeing never thought that the subsonic 747 would become famous. Regardless, Boeing went on to sell more than 1,554 jumbo passenger jets. You can easily convert these jets into cargo or passenger planes. The main competitor of Boeing is Airbus when it comes to Jumbo Jet sales.

2) Light Jets

The seating capacity in these jets ranges from 60-100. They can fly fast, making them an ideal choice for economy airlines. Their seating is evenly divided into two parts on each center aisle side. Light jets are famous for regional routes since they consume less fuel and need less investment.

3)  Wide-Body Airliners

These planes have more room, so passengers can easily move around. Their cabin diameter is between 5-6 meters. Passenger planes are very comfortable since they allow people to move around freely. Also, they have enough room for two passenger aisles. They can carry up to 850 passengers.

4) Narrow-Body Airliner

They are called single-aisle craft because they allow passengers to sit in one row. They also have a cabin with a diameter of at least 3-4 meters, allowing up to 6 abreast seats. The plane with the highest sitting capacity is the Boeing 757-300, which carries 295 passengers.

5) Mid-Size Airliners

These jets are liked by airliners since they sustain high profitability in seasonal routes. Their lower price tag also makes mid-size jets attractive to people who want to invest. 

6) Regional Airliners

These are Narrow Body aircraft with a short range that does not allow for transatlantic flights. Regional jets have a limited capacity of about 100 passengers and are more suitable for short flights. They are also known as Commuters or Feederliners because they feed into large commuter hubs. 

7) Military Jets

Lastly, the other most common type of aircraft that people are used to seeing in the sky are military airplanes and jets. There are a number of military aircraft including transporters, tankers, fighters, bombers, multirole, maritime, and more. 

Turboprop Airplane Engines

Many low speed transport aircraft and small commuter aircraft use turboprop propulsion.

There are two main parts to a turboprop propulsion system, the core engine and the propeller. The core is very similar to a basic turbojet except that instead of expanding all the hot exhaust through the nozzle to produce thrust, most of the energy of the exhaust is used to turn the turbine.

Types Of Turboprop Airplanes

1. Twin-turbo propeller plane 
2. Private single engine 
3. Military Turbo Propellers
4. Aerobatic planes
5. Amphibious 

Type Classified By Fleet Commonality

Fleet commonality is a term that you may come across in the world of commercial aviation. It refers to a shared characteristic between different aircraft types within a specific operator’s fleet. It is a simple concept regarding models that bear parallels. But it can be complicated depending on how a company defines such commonality. It can be about aircraft from the same class, as that shared between Airbus A321neo and A320neo.

However, there are also ways that different aircraft types can share a degree of commonality. For instance, you can find strong parallels between aircraft families like Airbus A340 and the A330 series. They have many structural similarities, the primary difference being the A340’s landing gear and four engines.

Regularly Scheduled Air Carriers, Part 121

The FAA gives the permit to operate scheduled air service in the form of a FAR 121 certificate. Generally, large aircraft such as regional air carriers, US-based airlines, and cargo operators are allowed to operate under this certificate. These air carriers are expected to have FAA-approved hazardous materials programs. Suppose an air carrier accepts to transport and handle dangerous items in the air. In that case, they have to create a detailed hazardous materials program detailing all aspects of the acceptance, transportation process, and training of employees.

Repair Station Operators, Part 145

A repair station is a term that refers to a maintenance facility with a certificate issued by the FAA under Title 14 found in the Code of Federal Regulations (14 CFR) Part 145. It is engaged in the inspection, maintenance, and alteration of aircraft products and aircraft. The FAA rules are straightforward on who can do maintenance and approve an airframe, engines, aircraft, etc., for return to service once maintenance has been performed.

A repair station must have the “Air Agency Certificate” certificate. This refers to aircraft repair tasks and services that a repair station is allowed to perform. A repair station can only perform the roles necessary to inspect, replace, repair, or overhaul the aviation services it has been authorized to perform. Some general ratings related to repair stations include;

1. Powerplant
2. Airframe
3. Radio
4. Propeller
5. Instrument
6. Accessory

Additionally, these ratings are further broken down into specific classes. For instance, an airframe rating consists of four classes. Two classes belong to either small or large sheet metal aircraft, while the other two are for either small or large composite aircraft. Also, engine ratings consist of three classes: two for reciprocating engines and one for greater than 400 horsepower or 400 horsepower or fewer engines. 

It’s important to note that many repair stations ship dangerous items like aircraft parts, pieces of equipment having lithium batteries, replacement items, and flammable solvents and paints. These parts must be well cleaned and purged of vapors to eliminate potential hazards. Also, parts that have residues should be secured and cushioned to prevent leakage and control movement within the package during transportation.

7 Common Aircraft Questions (FAQs)

1) What Is A “Taildragger” Aircraft?

These are aircraft that have a taildragger or conventional landing gear. It is characterized by the use of two main wheels at the front of an aircraft followed by a second smaller wheel towards the back of the plane. It is known as a taildragger since it encourages aircraft to drag their tail while taking off and landing. The back of the plane will shift downwards, thus allowing the secondary wheel to support the plane’s weight.

The taildragger landing gear is more common in many planes, primarily commercial airplanes, because they are heavy. They have passengers and cargo that shift their center of gravity to the back. The taildragger gear can support heavy planes due to the rear placement of the second wheel.

2) What Do The Terms “Narrow-Body” And “Wide-Body” Refer To When Speaking Of Commercial Jets?

A narrow-body is also known as a single-aisle aircraft. It is a smaller commercial jet usually used to operate domestic and short-haul international flights. It can carry as few as four passengers, and up to 300. 

On the other hand, a wide-body aircraft (twin-aisle aircraft) is a commercial jet with a vast fuselage that accommodates two passenger aisles with at least seven or more seats. Generally, it has a diameter of 5 to 6 meters. This means it can carry more passengers since it has more seats per row.

The difference between narrow and wide-body commercial jets is the fuselage width (the section where cargo, passengers, and crew sit). A narrow-body jet has a diameter of 3-4 meters, while a wide-body is 5-6 meters.

3) What Is An Afterburner, And What Does “Wet” Or “Dry” Mean?

It’s a piece of equipment found in many modern jets that burns additional fuel in the exhaust trail to offer extra propulsion. Afterburners are commonly found on military airplanes, although they have also been used on many supersonic commercial aircraft. The engine of a jet operates by igniting the fuel and removing mass behind it to create forward momentum. The turbines pull air in from the outside, compress it to high density, then add a fuel mix to the oxygen and ignite it. Using the turbine in a “normal” mode is known as “dry” or “military power,” while using it with an afterburner is known as “wet.”

4) What Jet Fuel Does Each Aircraft Require?

Generally, there are two common types of aircraft fuel, which are Jet Fuel and AVGAS. The right aircraft fuel depends mainly on the type of engine. AVGAS is usually used for piston-engine aircraft. These types of aircraft fly through the rotation of the propellers that generate the thrust. On the other hand, Jet Fuel is suitable for aircraft that have turbine engines. They fly with the thrust of expelled air.

5) What Is The Difference Between Jet A1 And Jet A?

Two types of Jet Fuel can be used correspondingly to control the turbine engines. They include Jet A and Jet A1. The main difference between the two are:

• Additives: Jet A type doesn’t regularly include static dissipater additives. The additives help to reduce the static charges that can form due to the movement of Jet Fuel. While Jet 1A usually contains static dissipater additives.
• Freezing points: Jet A1 has a freezing point of -40 degrees Celsius, while Jet A freezes at -47. Jet A1 is more suitable for long international flights due to its lower freezing points.
• Jet A is commonly used in the US, while the rest of the world uses Jet A1.

6) To What Does The Term ETOPS Refer?

The term ETOPS is an acronym for Extended-range Twin-engine Operational Performance Standards. Simply put, it refers to regulations and rules established regarding the operational performance of aircraft with twin engines to ensure safety.

7) What Does It Mean To Speak Of “Thrust” With A Jet Engine?

Thrust is an invisible but powerful force that enables the airplane to move forward. Aircraft have one or more engines. Some use jet engines, while others use propeller engines. Regardless of the engine type, they all create thrust to enable airplanes to move while in the air.

To understand thrust, look at Newton’s Third Law. Based on this law, there is an equal and opposite reaction for every action. So, when an aircraft engine is activated, it creates an action. A response to this action is a movement that moves the airplane forward. 

PartsBase For Aircraft Expertise 

These are just a few examples of ways to classify, categorize, and identify aircraft, but there are many others, including manufacturer, size, weight, speed, and travel distance. You can learn more about aircraft and their parts from PartsBase. Do research, find, buy, and sell aircraft and aircraft parts with PartsBase PartStore, or get in touch with us with questions or concerns.