(1) Still air and standard atmosphere; and
(2) Ambient atmospheric conditions, for commuter category airplanes, for reciprocating engine-powered airplanes of more than 6,000 pounds maximum weight, and for turbine engine-powered airplanes.
(b) Performance data must be determined over not less than the following ranges of conditions—
(1) Airport altitudes from sea level to 10,000 feet; and
(2) For reciprocating engine-powered airplanes of 6,000 pounds, or less, maximum weight, temperature from standard to 30 °C above standard; or
(3) For reciprocating engine-powered airplanes of more than 6,000 pounds maximum weight and turbine engine-powered airplanes, temperature from standard to 30 °C above standard, or the maximum ambient atmospheric temperature at which compliance with the cooling provisions of §23.1041 to §23.1047 is shown, if lower.
(c) Performance data must be determined with the cowl flaps or other means for controlling the engine cooling air supply in the position used in the cooling tests required by §23.1041 to §23.1047.
(d) The available propulsive thrust must correspond to engine power, not exceeding the approved power, less—
(1) Installation losses; and
(2) The power absorbed by the accessories and services appropriate to the particular ambient atmospheric conditions and the particular flight condition.
(e) The performance, as affected by engine power or thrust, must be based on a relative humidity:
(1) Of 80 percent at and below standard temperature; and
(2) From 80 percent, at the standard temperature, varying linearly down to 34 percent at the standard temperature plus 50 °F.
(f) Unless otherwise prescribed, in determining the takeoff and landing distances, changes in the airplane's configuration, speed, and power must be made in accordance with procedures established by the applicant for operation in service. These procedures must be able to be executed consistently by pilots of average skill in atmospheric conditions reasonably expected to be encountered in service.
(g) The following, as applicable, must be determined on a smooth, dry, hard-surfaced runway—
(1) Takeoff distance of §23.53(b);
(2) Accelerate-stop distance of §23.55;
(3) Takeoff distance and takeoff run of §23.59; and
(4) Landing distance of §23.75.
Note: The effect on these distances of operation on other types of surfaces (for example, grass, gravel) when dry, may be determined or derived and these surfaces listed in the Airplane Flight Manual in accordance with §23.1583(p).
(h) For commuter category airplanes, the following also apply:
(1) Unless otherwise prescribed, the applicant must select the takeoff, enroute, approach, and landing configurations for the airplane.
(2) The airplane configuration may vary with weight, altitude, and temperature, to the extent that they are compatible with the operating procedures required by paragraph (h)(3) of this section.
(3) Unless otherwise prescribed, in determining the critical-engine-inoperative takeoff performance, takeoff flight path, and accelerate-stop distance, changes in the airplane's configuration, speed, and power must be made in accordance with procedures established by the applicant for operation in service.
(4) Procedures for the execution of discontinued approaches and balked landings associated with the conditions prescribed in §23.67(c)(4) and §23.77(c) must be established.
(5) The procedures established under paragraphs (h)(3) and (h)(4) of this section must—
(i) Be able to be consistently executed by a crew of average skill in atmospheric conditions reasonably expected to be encountered in service;
(ii) Use methods or devices that are safe and reliable; and
(iii) Include allowance for any reasonably expected time delays in the execution of the procedures.
[Doc. No. 27807, 61 FR 5184, Feb. 9, 1996]