Source: https://captainslog.aero/2012/faa-airplane-categories/
Timestamp: 2019-04-26 16:16:51+00:00

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Aircraft categories, with respect to the certification of aircraft, are defined as “a grouping of aircraft based upon intended use or operating limitations.” This is a topic in need of disentanglement. I will focus on airplane categories to establish a concise point-of-reference.
Before today, searching for this information could be very frustrating because, officially, it falls under the heading of “Airworthiness certificates: classification,” better known as 14 CFR § 21.175. This is the only place I could find all eleven categories mentioned.
Airplane categories, 14 CFR § 23.3, defines four of the five Standard categories.
Transport Airplanes is an FAA web page that offers a definition of the Transport category. I have yet to find the regulatory source of that definition.
Special Airworthiness Certificate is an FAA web page that summarizes all of the Special categories, with links to applicable type certification and airworthiness certification paragraphs in 14 CFR § 21.
With respect to the certification of airmen, all airplanes are grouped into the airplane category.
With respect to the operation of aircraft, Category II, and Category III, etc., are defined in 14 CFR § 1.1 and 14 CFR § 91.189, etc.
With respect to terms used in instrument flight, Category A, and Category B, etc., are “a grouping of aircraft based on a speed of VREF,” as defined by the Terminal Procedures Publication.
The phrases “large transport category” and “small transport category” are used in various parts of the regulations, but are not defined as classifications for airworthiness. “Large aircraft” and “small aircraft” are both defined in 14 CFR § 1.1 with respect to the weight of an aircraft. These distinctions do imply that the transport category includes aircraft of any weight, whereas large aircraft are excluded by definition from the other Standard categories.
I would like to know that the a/c used in training / flying schools are which category such as aerial work or commercial category.
The small airplanes used at traditional flight schools are in the Normal category. Some of them are certified in both the Normal and Utility categories. Of course, it is also possible to get training in a Light-Sport category, or an Acrobatic category airplane.
Question 3003 of the 2013 of the Private Pilot exam reads “with respect to the certification of aircraft, which is a category of aircraft? A) Normal, utility, acrobatic. B) Airplane, rotorcraft, glider. C) Landplane, seaplane.
Doesn’t answer A actually give 3 categories and not a single one as the questions asks for?
That is correct. This question provides multiple examples.
Robert: FAR 135 performance regulations (135.365 through 135.398) talks about “Part 25 transport category airplanes” Large non-transport category”, “small transport category” and “commuter category airplanes”. It appears that a “small transport category” is an airplane that with a GTOW of greater than 12,500 pounds or turbojet powered, with less than 10 passenger seats, and a large transport category airplane is any airplane certificated under FAR 25 (or CAR 4) that isn’t commuter category, i.e. a GTOW greater than 19,000 lbs and/or more than 19 pax seats.
Hi Reo, unless there is a specific reference to the contrary, I would think a large nontransport category airplane is a commuter weighing between 12,501 and 19,000 lbs. A small aircraft is 12,500 lbs or less by definition.
I am trying to make sense of aircraft that are only certified in the Utility Category (Beech Skipper, C-150, C-152, Tomahawk, and surprisingly Bonanzas). A C-172 has a 5.5 inch CG range in the Utility Category but it has a 12 inch CG range when operated as a Normal Category aircraft. If the Normal Envelope is more than twice the size of the Utility Envelope, how much wiggle room can you conclude is available beyond the aft CG limit of Utility only aircraft. As long as you are not doing any spins or abrupt stalls, I am sure you should be able to fly from point A to Point B with a training aircraft that is loaded a couple of inches aft of the Utility envelope since you are only operating under the constraints of a Normal category operation. This is a recurring problem for tall (over 6 feet) and heavy(over 200 lbs) pilots and passengers in small training aircraft. We are constantly busting the aft CG limit by about 1-2 inches since the seats all the way back and the weight is high. The only way to get back inside the Utility envelope is move the seats forward 2-3 detente stops (or purge your passenger). Why do I have to stay inside the Utility envelope when I am not doing any Utility maneuvers? Why don’t these airplanes have a larger Normal envelope like the C-172 does?
Hi Mike, thank you for writing. It sounds like you might be confusing the CG limits with load limits. While it would be possible to stay within the Normal category load limits behind the rear limit of the flight envelope, one must remember that the load limit is only one of many factors that determine the flight envelope limitations of an airplane. It is definitely not safe to assume that the airplane can fly or even taxi safely beyond those limitations.
With that said, I would suggest that you carefully investigate the empty weight CG of the aircraft. The last time I had a problem with the rear limit of a flight envelope, I figured out that the empty weight CG was positioned so far rearward that the airplane could not legally carry any load. Someone had falsified the weight and balance report! I raised hell about it with management and refused to fly the airplane until it was weighed again.
When all is said and done, if you are carrying more than 400 lbs worth of pilots at the rear stop of a C-152, there is usually a fuel issue. You might need to make adjustments or upgrade your heavier students to the C-172.

References: § 21
 § 23
 § 21
 § 1
 § 91
 § 1