(a) This part prescribes airworthiness standards for the issue of type certificates, and changes to those certificates, for small airplanes in the normal, utility, and acrobatic categories.

(b) Each person who applies under Part 21 for such a certificate or change must show compliance with the applicable requirements of this part.

§ 23.3 Airplane categories.

(a) The normal category is limited to airplanes intended for nonacrobatic operation. Nonacrobatic operation includes any maneuvers incident to normal flying, stalls (except whip stalls), and turns in which the angle of bank is not more than 60 degrees.

(b) The utility category is limited to airplanes intended for limited acrobatic operation. Limited acrobatic operation includes any maneuvers incident to normal flying, stalls (except whip stalls), spins (if approved for the particular type of airplane), lazy eights, chandelles, and steep turns in which the angle of bank is more than 60 degrees.

(c) The acrobatic category is limited to airplanes intended for use without restrictions other than those shown to be necessary as a result of required flight tests.

(d) Small airplanes may be certificated in more than one category if the requirements of each requested category are met.

(a) Maximum weight. The maximum weight (the highest weight at which compliance with each applicable requirement of this part is shown) must be established so that it is

(1) Not more than

(i) The highest weight selected by the applicant;

(ii) Except as provided in § 23.473 for multiengine airplanes, the design maximum weight (the highest weight at which compliance with each applicable structural loading condition of this part is shown); or

(iii) The highest weight at which compliance with each applicable flight requirement is shown, except for airplanes equipped with standby power rocket engines, in which case it is the highest weight established in accordance with Appendix E of this part.

(2) Assuming a weight of 170 pounds for each occupant of each seat for normal category airplanes and 190 pounds (unless otherwise placarded) for utility and acrobatic category airplanes, not less than the weight with—

(1) Each seat occupied, oil at full tank capacity, and at least enough fuel for one-half hour of operation at rated maximum continuous power; or

(ii) The required minimum crew, and fuel and oil to full tank capacity.

(b) Minimum weight. The minimum weight (the lowest weight at which compliance with each applicable requirement of this part is shown) must be established so that it is not more than the sum of

(1) The empty weight determined under § 23.29;

(2) The weight of the required minimum crew (assuming a weight of 170 pounds for each crewmember);

(3) The weight of the oil at full tank capacity; and

(4) The weight of no more than the quantity of fuel necessary for one-half hour of operation at rated maximum continuous power.

[Doc. No. 4080, 29 F.R. 17955, Dec. 18, 1964, as amended by Amdt. 23-2, 30 F.R. 8468, July 2, 1965]

assure safe operation under normal operating conditions.

(b) Propellers not controllable in flight. For each propeller whose pitch cannot be controlled in flight—

(1) During takeoff and initial climb at Vy, the propeller must limit the engine r.p.m., at full throttle or at maximum allowable takeoff manifold pressure, to a speed not greater than the maximum allowable takeoff r.p.m.; and

(2) During a closed throttle glide at the placarded "never-exceed speed", the propeller may not cause an engine speed above 110 percent of maximum continuous speed.

(c) Controllable pitch propellers without constant speed controls. Each propeller that can be controlled in flight, but that does not have constant speed controls, must have a means to limit the pitch range so that

(1) The lowest possible pitch allows compliance with paragraph (b)(1) of this section; and

(2) The highest possible pitch allows compliance with paragraph (b)(2) of this section.

(d) Controllable pitch propellers with constant speed controls. Each controllable pitch propeller with constant speed controls must have

(1) With the governor in operation, a means at the governor to limit the maximum engine speed to the maximum allowable takeoff r.p.m.; and

(2) With the governor inoperative, a means to limit the maximum engine speed to 103 percent of the maximum allowable takeoff r.p.m. with the propeller blades at the lowest possible pitch and with takeoff manifold pressure, the airplane stationary, and no wind.

(1) Engines idling, throttles closed (or at not more than the power necessary for zero thrust at a speed not more than 110 percent of the stalling speed);

(2) Propellers in the takeoff position; (3) Landing gear extended;

(4) Wing flaps in the landing position; (5) Cowl flaps closed;

(6) Center of gravity in the most unfavorable position within the allowable landing range; and

(7) Weight used when Vso is being

used as a factor to determine compliance with a required performance standard. (b) Vso at maximum weight may not exceed 70 miles per hour for

(1) Single-engine airplanes; and (2) Multiengine airplanes of 6,000 pounds or less maximum weight that cannot meet the minimum rate of climb specified in § 23.67 (b) with the critical engine inoperative.

(c) Vg is the calibrated stalling speed, 81 if obtainable, or the minimum steady speed, in miles per hour, at which the airplane is controllable, with the

(1) Engines idling, throttles closed (or at not more than the power necessary for zero thrust at a speed not more than 110 percent of the stalling speed);

(2) Propellers in the takeoff position: (3) Airplane in the condition existing in the test in which Vs, is being used;

(a) For airplanes of more than 6,000 pounds maximum weight (except skiplanes for which landplane takeoff data has been determined under this paragraph and furnished in the Airplane Flight Manual).

(1) The distance required to take off and climb over a 50-foot obstacle must be determined with

(1) The engines operating within approved operating limitations; and

(ii) The cowl flaps in the normal takeoff position;

(2) Upon reaching a height of 50 feet above the takeoff surface level, the airplane must have reached a speed of not less than

(1) 1.3 Vs1; or

(ii) Any lesser speed, not less than Và plus 5 miles per hour, that is shown to be safe under any condition, including turbulence and complete engine failure;

(3) The starting point for measuring seaplane and amphibian takeoff distance may be the point at which a speed of not more than three miles per hour is reached; and

(4) No takeoff made to determine the data required by this section may require exceptional piloting skill or exceptionally favorable conditions.

(b) For airplanes of 6,000 pounds or less maximum weight

(1) The takeoff may not require exceptional piloting skill;

(2) With takeoff power, there must be enough elevator control

(i) For a tail-wheel type airplane, to maintain, at 0.8 Vs,, an attitude that will allow holding the airplane on the runway until a safe takeoff speed is reached; and (ii) For a nose-wheel type airplane to raise the nose-wheel clear of the takeoff surface at 0.85 Vs,.

§ 23.65

Climb: all engines operating.

(a) For airplanes of more than 6,000 pounds maximum weight—

(1) Each airplane must have a steady rate of climb at sea level of at least 300 feet per minute and a steady angle of climb of at least 1:12 for land planes or 1:15 for seaplanes and amphibians with

(1) Not more than maximum continuous power on each engine;

(ii) The landing gear retracted;

(iii) The wing flaps in the takeoff position; and

(iv) The cowl flaps in the position used in the cooling tests required by §§ 23.1041 through 23.1047;

(2) Each airplane with engines for which the takeoff and maximum continuous power ratings are identical and that has fixed-pitch, two-position, or similar propellers, may use a lower propeller pitch setting than that allowed by § 23.33 to obtain rated engine r.p.m. at Vr, if

(1) The airplane shows marginal performance (such as when it can meet the rate of climb requirements of paragraph (a)(1) of this section but has difficulty in meeting the angle of climb requirements of paragraph (a) (1) of this section or of § 23.77); and

(ii) Acceptable engine cooling is shown at the lower speed associated with the best angle of climb.

(b) Each airplane of 6,000 pounds or less maximum weight must have a steady rate of climb at sea level of at least 300

feet per minute, or 10 Vs, (that is, the number of feet per minute is obtained by multiplying the number of miles per hour by 10), whichever is greater, with(1) Takeoff power;

(2) The landing gear extended; (3) The wing flaps in the takeoff position; and

(4) The cowl flaps in the position used in the cooling tests required by §§ 23.1041 through 23.1047.

§ 23.67 Climb: one engine inoperative. (a) Each multiengine airplane of more than 6,000 pounds maximum weight must be able to maintain a steady

rate of climb of at least 0.02 Vso 2 (that is,

the number of feet per minute is obtained by multiplying the square of the number of miles per hour by 0.02) at an altitude of 5,000 feet with the

(1) Critical engine inoperative, and its propeller in the minimum drag position; (2) Remaining engines at not more than maximum continuous power;

(3) Landing gear retracted;

(4) Wing flaps in the most favorable position; and

(5) Cowl flaps in the position used in the cooling tests required by §§ 23.1041 through 23.1047.