shall be determined under the following conditions: (1) At all weights, altitudes, and temperatures selected by the applicant, and (2) With the operating engines not exceeding their approved limitations. (c) All take-off data, when corrected, shall assume a level take-off surface, and shall be determined on a smooth, dry, hard surface, and in such a manner that reproduction of the performance does not require either exceptional skill or alertness on the part of the pilot or exceptionally favorable conditions. (For wind and runway gradient corrections see appropriate operating rules of the regulations in this subchapter.) § 7.113 Category A; critical decision point. The critical decision point shall be any combination of height and speed as selected by the applicant in demonstrating the take-off as defined in § 7.114. The method used to attain the critical decision point shall be such as to avoid flight within the critical areas of the limiting height-speed envelope as established in accordance with § 7.111 (a). § 7.114 Take-off. (a) Category A. The take-off flight path and rejected take-off path shall be established. It shall be permissible to initiate the take-off in any manner provided the take-off surface is defined and adequate safeguards are maintained to assure proper center of gravity position and control position. (1) The rejected take-off path shall be established with take-off power on all engines from the start of take-off to the critical decision point, at which point it shall be assumed that the critical engine becomes inoperative, and the rotorcraft is brought to a safe stop with the remaining engines operating within their approved limitations. (2) The take-off climb-out path shall be established with take-off power on all engines from the start of take-off to the critical decision point, at which point it shall be assumed that the critical engine becomes inoperative. With the remaining engines operating within their approved limitations, the rotorcraft shall be accelerated such that the take-off safety speed is reached by the end of the rejected take-off distance and the climbout shall be accomplished at speeds not less than the take-off safety speed used in meeting the rate of climb specified in § 7.115(a) (1), and in such a manner that the air-speed and configuration used in meeting the climb requirement specified in § 7.115(a) (2) are attained. (3) The take-off climb-out and rejected take-off shall be accomplished in such a manner as to provide a safe and smooth transition between all stages of the maneuver. (b) Category B. The take-off and climb-out shall be established with the most unfavorable center of gravity position. It shall be permissible to initiate the take-off in any manner provided the take-off surface is defined and adequate safeguards are maintained to assure proper center of gravity position and control position and provided a landing can be made safely at any point along the flight path in the case of an engine failure (see § 7.111 (b)). [21 F.R. 3744, June 2, 1956, as amended by Amdt. 7-2, 23 F.R. 2593, Apr. 19, 1958] § 7.115 Climb; one-engine-inoperative. (a) Category A. The following takeoff and en route climb requirements shall be met by all Category A rotorcraft: (1) Take-off climb; gear extended. The steady rate of climb without ground effect shall not be less than 100 fpm for each weight, altitude, and temperature condition for which take-off data are to be scheduled with: (i) The critical engine inoperative and the remaining engine(s) operating within their approved limitations, (ii) Center of gravity in the most unfavorable position permitted for takeoff, (iii) Landing gear extended, (iv) The take-off safety speed as selected by the applicant (see § 7.114 (a) (2)), and (v) Cowl flaps or other means of controlling the engine-cooling air supply in the position which provides adequate cooling at the temperatures and altitudes for which certification is sought. (2) Climb at maximum continuous power. The steady rate of climb without ground effect shall not be less than 150 fpm for each weight, altitude, and temperature condition for which takeoff data are to be scheduled with: (i) The critical engine inoperative and the remaining engine(s) operating at maximum continuous power, (ii) Center of gravity in the most unfavorable position permitted for take-off, (iii) Landing gear retracted, if retractable, (iv) The speed as selected by the applicant, and (v) Cowl flaps or other means of controlling the engine-cooling air supply in the position which provides adequate cooling at the temperatures and altitudes for which certification is sought. (3) En route climb. The steady rate of climb in feet per minute at any altitude at which the rotorcraft is expected to operate, and at any weight within the range of weights to be specified in the airworthiness certificate, shall be determined with: (i) The critical engine inoperative, and the remaining engine(s) operating at the maximum continuous power available at such altitude, (ii) Center of gravity in the most unfavorable position, (iii) The landing gear retracted, if retractable, (iv) The speed as selected by the applicant, and (v) Cowl flaps or other means of controlling the engine-cooling air supply in the position which provides adequate cooling at the temperatures and altitudes for which certification is sought. (b) Category B. The following climb requirements shall be applicable to Category B rotorcraft: (1) For all rotorcraft, the steady rate of climb at the best rate-of-climb speed with maximum continuous power on all engines and landing gear retracted, if retractable, shall be determined over the range of weights, altitudes, and temperatures for which certification is sought (see § 7.740). For all rotorcraft except helicopters this rate of climb shall provide a steady gradient of climb under standard sea level conditions of not less than 1:6. (2) For multiengine helicopters complying with the optional requirement of § 7.111 (c), the steady rate of climb or descent shall be determined at the best rate-of-climb or rate-of-descent speed with one engine inoperative and the remaining engine(s) operating at a maximum continuous power. (3) For all helicopters, the steady angle of glide shall be determined at the maximum and minimum rate-of-descent speed in autorotation at maximum weight at the optimum forward speed. [21 F.R. 3744, June 2, 1956, as amended by Amdt. 7-2, 23 F.R. 2593, Apr. 19, 1958] § 7.116 Hovering or minimum operating performance. (a) Category A: The hovering performance shall be determined over the range of weights, altitudes, and temperatures for which take-off data are scheduled with not more than take-off power on all engines, landing gear extended, and at a height above the ground consistent with the procedure used in the establishment of take-off and acceleratestop distance. (b) Category B: Hovering performance for helicopters shall be determined over the range of weights, altitudes, and temperatures for which certification is sought with take-off power on all engines, landing gear extended, and in the ground effect at a height above the ground consistent with normal take-off procedures. At maximum weight, under standard atmospheric conditions and under the aforementioned conditions, the hovering ceiling for helicopters shall not be less than 4,000 feet. (c) For rotorcraft other than helicopters, the steady rate of climb at the minimum operating speed appropriate to the type with take-off power and landing gear extended shall be determined over the range of weights, altitudes, and temperatures for which certification is sought. § 7.117 Landing; general. (a) Category A: The landing performance shall be determined and scheduled in such a manner that, in the event of one engine becoming inoperative at any point in the approach path, it shall be possible for the rotorcraft to land and stop safely, and, further, it shall be possible from a point in the approach path to climb out and attain a rotorcraft configuration and air speed at which compliance with the climb requirement of § 7.115(a) (2) is met. (b) The landing data required by § 7.118 shall be determined under the following conditions: (1) At all weights, altitudes, and temperatures selected by the applicant, and (2) With the operating engines not exceeding their approved limitations. (c) The approach and landing shall be made in such a manner that its reproduction does not require an exceptional degree of skill on the part of the pilot or exceptionally favorable conditions. (d) During the landing there shall be no excessive vertical acceleration and no tendency to bounce, nose over, ground loop, porpoise, or water loop. All landing data, when corrected, shall assume a level landing surface, and shall be determined on a smooth, dry, hard surface. (For wind and runway gradient corrections see appropriate operating rules of the regulations in this subchapter.) (a) Category A; one engine inoperative. The approach, balked landing, and landing paths shall be established. The approach and landing speeds shall be selected by the applicant and be appropriate to the type of rotorcraft being certificated. Such paths shall be established in the following manner: (1) The approach and landing path shall be established such as to avoid flight within the critical areas of the limiting height-speed envelope as established in accordance with § 7.111 (a) or, alternatively, at the option of the applicant, an envelope established in accordance with the landing condition with one engine inoperative. (2) The balked-landing path shall be established such that, from a height and speed combination in the approach path as selected by the applicant, a safe climbout can be made and speeds attained corresponding to the speeds required in meeting the climb requirements of § 7.115 (a) (1) and (2). (3) The maneuvers specified in subparagraphs (1) and (2) of this paragraph shall be accomplished in such a manner as to provide safe and smooth transition between each stage. (b) Category A; complete failure of all power. It shall be possible to make a safe landing on a prepared runway following complete failure of all power during normal cruising operating conditions (see § 7.743 (a) (2)). The maximum permissible descent speed in autorotation shall be determined. (c) Category B; autorotative landing. The horizontal distance required to land and come to a complete stop (to a speed of approximately 3 mph for seaplanes or float planes) from a point at a height of 50 feet above the landing surface shall be determined. In making this determination the following shall apply: (1) The approach speed or speeds in the glide shall be appropriate to the type of rotorcraft and shall be chosen by the applicant. (2) The approach and landing shall be made with power off and shall be entered from steady autorotation. (d) Category B-Optional requirements for multiengined rotorcraft certificated in Transport Category B. In lieu of compliance with the autorotative landing distance requirements specified in paragraph (c) of this section, a multiengined rotorcraft that complies with the powerplant installation requirements for Category A may, at the option of the applicant, comply with paragraphs (a) and (b) of this section, omitting the climb-out requirement specified in paragraph (a) (2) of this section. [21 F.R. 3744, June 2, 1956, as amended by Amdt. 7-2, 23 F.R. 2593, Apr. 19, 1958; Amdt. 7-3, 23 F.R. 3514, May 22, 1958] (a) The rotorcraft shall comply with the requirements prescribed in §§ 7.121 through 7.123 at all normally expected operating altitudes, under all critical loading conditions within the range of weight and center of gravity, and for all speeds, power, and rotor rpm conditions for which certification is sought. (b) It shall be possible to maintain a flight condition and to make a smooth transition from one flight condition to another without requiring an exceptional degree of skill, alertness, or strength on the part of the pilot, and without danger of exceeding the limit load factor under all conditions of operation probable for the type, including those conditions normally encountered in the event of sudden powerplant failure. (c) For night or instrument certification the rotorcraft shall have such additional flight characteristics as the Administrator finds are required for safe operation under these conditions. [21 F.R. 3744, June 2, 1956, as amended by Amdt. 7-4, 24 F.R. 7075, Sept. 1, 1959] § 7.121 Controllability. (a) The rotorcraft shall be safely controllable and maneuverable during = steady flight and during the execution of any maneuver appropriate to the type of rotorcraft, including take-off, climb, = level flight, turn, glide, and power-on or power-off landings. (b) The margin of longitudinal and lateral cyclic control shall allow satisI factory pitching and rolling control at VNE (see § 7.711), with: (1) Maximum weight, (2) Critical center of gravity, (3) Power on and power off, and (4) Critical rotor rpm. (c) Compliance with paragraph (b) of this section shall include a demonstration with a power failure at VH or VNE, whichever is less. (d) There shall be established a wind velocity in which the rotorcraft can be operated without loss of control on or near the ground at the critical center of gravity and the critical rotor rpm in any maneuver appropriate to the type of rotorcraft; e. g., cross-wind take-offs, sideward or rearward flight. This wind velocity shall not be less than 20 mph. (e) Controllability after power failure shall be demonstrated over the range of air speeds and altitudes for which certification is sought, starting with maximum continuous power at critical weight. In taking corrective action, the time delay for all flight conditions shall be based on the normal pilot reaction time, except that for the cruise condition the time delay shall not be less than one second. [21 F.R. 3744, June 2, 1956, as amended by Amdt. 7-4, 24 F.R. 7075, Sept. 1, 1959] § 7.122 Trim. (b) Static longitudinal stability. In the following configurations the characteristics of the longitudinal cyclic control shall be such that, with constant throttle and collective pitch settings, a rearward displacement of longitudinal control shall be necessary to obtain speeds below the specified trim speed, and a forward displacement shall be necessary to obtain speeds above the specified trim speed for the ranges of altitude and rotor rpm for which certification is sought: (1) Climb. At all speeds from 0.85VY to 1.2V, with: (i) Critical weight and center of gravity, (ii) Maximum continuous power, (iii) Landing gear retracted, and (iv) Trim at best rate-of-climb speed (Vy). (2) Cruise. At all speeds from 0.7VH or 0.7VNE, whichever is less, to 1.1V or 1.1VNE, whichever is less, with: (i) Critical weight and center of gravity, (ii) Power for level flight at 0.9 Vн oг 0.9 VNE, whichever is less. (iii) Landing gear retracted, and (iv) Trimmed at 0.9 VH, or 0.9 VNE, whichever is less. (3) Autorotation. Throughout the speed range for which certification is sought, with: (i) Critical weight and center of gravity, (ii) Power off, (iii) Landing gear both retracted, if retractable, and extended, and (iv) Trim at the speed for minimum rate of descent. (4) Hovering. In the case of helicopters the stick position curve shall have a stable slope between the maximum approved rearward speed and a forward speed of 20 mph, with: (i) Critical weight and center of gravity, except for Category A helicopters the weight shall be that determined for hovering. (See § 7.116(a).) (ii) Power required for hovering in still air, (iii) Landing gear retracted, and NOTE: It is considered acceptable for the stick position versus speed curve to have a negative slope within the speed range specified for each of the conditions in subparagraphs (1) through (3) of this paragraph, The rotorcraft shall be demonstrated to have satisfactory ground and water handling characteristics. There shall be no uncontrollable tendencies in any operating condition reasonably expected for the type. § 7.131 Ground resonance. There shall be no tendency for the rotorcraft to oscillate when the rotor is turning and the rotorcraft is on the ground unless the Administrator finds that such tendencies are not dangerous. [21 F.R. 3744, June 2, 1956, as amended by Amdt. 7-2, 23 F.R. 2594, Apr. 19, 1958] § 7.132 Spray characteristics. For rotorcraft equipped with floats, the spray characteristics during taxying, take-off, and landing shall be such as not to obscure the vision of the pilot nor produce damage to the rotors, propellers, or other parts of the rotorcraft. MISCELLANEOUS FLIGHT REQUIREMENTS § 7.140 Flutter and vibration. All parts of the rotorcraft shall be demonstrated to be free from flutter and excessive vibration under all speed and power conditions appropriate to the operation of the type of rotorcraft. (See also §§ 7.203 (f) and 7.711.) Subpart C-Structure § 7.200 Loads. GENERAL (a) Strength requirements of this subpart are specified in terms of limit and ultimate loads. Unless otherwise stated, the specified loads shall be considered as limit loads. In determining compliance with these requirements the provisions set forth in paragraphs (b) through (e) of this section shall apply. (b) The factor of safety shall be 1.5 unless otherwise specified, and shall apply to the external and inertia loads, unless its application to the resulting internal stresses is more conservative. (c) Unless otherwise provided, the specified air, ground, and water loads shall be placed in equilibrium with inertia forces, considering all items of mass in the rotorcraft. (d) All loads shall be distributed in a manner closely approximating or conservatively representing actual conditions. (e) If deflections under load significantly change the distribution of external or internal loads, the redistribution shall be taken into account. §7.201 Strength and deformation. (a) The structure shall be capable of supporting limit loads without suffering detrimental permanent deformations. (b) At all loads up to limit loads the deformation shall not be such as to interfere with safe operation of the rotorcraft. (c) The structure shall be capable of supporting ultimate loads without failure. It shall support the load during a static test for at least 3 seconds, unless proof of strength is demonstrated by dynamic tests simulating actual conditions of load application. § 7.202 Proof of structure. (a) Proof of compliance of the structure with the strength and deformation requirements of § 7.201 shall be made for all critical loading conditions. (b) Proof of compliance by means of structural analysis shall be acceptable only when the structure conforms to types for which experience has shown such methods to be reliable. In all other cases substantiating tests shall be required. (c) In all cases certain portions of the structure shall be tested as specified in § 7.203. § 7.203 Structural and dynamic tests. At least the following structural tests shall be conducted to show compliance with the strength criteria: (a) Dynamic and endurance tests of rotors and rotor drives, including controls (see § 7.405). (b) Control surface and system limit load tests (see § 7.323). (c) Control system operation tests (see § 7.324). (d) Flight stress measurements (see §§ 7.221, 7.250, and 7.251). |