Source: https://www.federalregister.gov/articles/2011/03/28/2011-7144/special-conditions-gulfstream-model-gvi-airplane-high-incidence-protection
Timestamp: 2016-02-06 13:38:37
Document Index: 97233309

Matched Legal Cases: ['art 25', 'art 25', '§ 21', '§ 21', 'art 34', 'art 36', '§ 11', '§ 21', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25', '§ 25']

Federal Register | Special Conditions: Gulfstream Model GVI Airplane; High Incidence Protection
-17025 (4 pages)
Document Number: 2011-7144
Shorter URL: https://federalregister.gov/a/2011-7144 Related Topics
Under provisions of Title 14 Code of Federal Regulations (14 CFR) 21.17, Gulfstream must show that the Gulfstream Model GVI airplane (hereafter referred to as “the GVI”) meets the applicable provisions of 14 CFR part 25, as amended by Amendments 25-1 through 25-119, 25-122 and 25-124. If the Administrator finds that the applicable airworthiness regulations (i.e., 14 CFR part 25) do not contain adequate or appropriate safety standards for the GVI because of a novel or unusual design feature, special conditions are prescribed under the provisions of § 21.16.
Special conditions are initially applicable to the model for which they are issued. Should the type certificate for that model be amended later to include any other model that incorporates the same novel or unusual design features, the special conditions would also apply to the other model under the provisions of § 21.101.
In addition to complying with the applicable airworthiness regulations and special conditions, the GVI must comply with the fuel vent and exhaust emission requirements of 14 CFR part 34 and the noise certification requirements of 14 CFR part 36. The FAA must also issue a finding of regulatory adequacy pursuant to section 611 of 92, the “Noise Control Act of 1972.”
The FAA issues special conditions, as defined in 14 CFR 11.19, in accordance with § 11.38, and they become part of the type certification basis under § 21.17(a)(2).
The GVI is equipped with a novel or unusual design feature: A high incidence protection system that replaces the stall warning system during normal operating conditions, prohibits the airplane from stalling, limits the angle of attack at which the airplane can be flown during normal low speed operation, and cannot be overridden by the flight crew. The system's application of this angle of attack limit impacts the stall speed determination, the stall characteristics, the stall warning demonstration, and the longitudinal airplane handling characteristics. The current regulations, including §§ 25.103, 25.145, 25.201, 25.203, 25.207 and 25.1323, do not address this type of protection feature.
These special conditions, which include airplane performance requirements, will establish a level of safety equivalent to the current regulations for reference stall speeds, stall warning, stall characteristics, and miscellaneous other minimum reference speeds.
2. Capability and Reliability of the High Incidence Protection System—In lieu of §§ 25.103, 25.145, 25.201, 25.203, 25.207 and 25.1323, the following special conditions are issued for capability and reliability requirements:
(d) The reliability of the high incidence protection function and the effects of failures must be acceptable in accordance with § 25.1309.
3. Minimum Steady Flight Speed and Reference Stall Speed—In lieu of the requirements of § 25.103, the following special condition is issued:
(4) The weight used when V SR is being used as a factor to determine compliance with a required performance standard.
(6) The airplane trimmed for straight flight at a speed selected by the applicant, but not less than 1.13 V SR and not greater than 1.3 V SR.
n ZW= load factor normal to the flight path at V min.
(d) The reference stall speed, V SR, is a calibrated airspeed selected by the applicant. V SR may not be less than a 1g stall speed. V SR is expressed as:
(e) V SR must be determined with the following conditions:
(2) The airplane in other respects (such as flaps and landing gear) in the condition existing in the test or performance standard in which V SR is being used.
(3) The weight used when V SR is being used as a factor to determine compliance with a required performance standard.
(5) The airplane trimmed for straight flight at a speed selected by the applicant, but not less than 1.13 V SR and not greater than 1.3 V SR.
(f) The flight characteristics at the angle of attack corresponding to V SR must be suitable in the traditional sense at forward and aft center of gravity in straight and turning flight at IDLE power.
(g) If V SR is chosen equal to V MIN,1g, an equivalent safety finding to the intent of § 25.103 may be considered to have been met. The applicant may choose V SR to be less than V MIN,1g but not less than V S1g if compensating factors are provided to ensure safe characteristics.
(a) Normal Operation—If the conditions of paragraph 2 of this special condition are satisfied, a level of safety equivalent to that intended by § 25.207, Stall warning, will have been met.
(b) Failure Cases—Following failures of the high incidence protection function not shown to be extremely improbable, if the function no longer satisfies paragraphs 2(a), 2(b), and 2(c) of this special condition, stall warning must be provided in accordance with § 25.207. The stall warning should prevent inadvertent stall in the following conditions:
5. High Incidence Handling Demonstrations—In lieu of the requirements of § 25.201, the following special condition are issued:
(3) At a power level necessary to maintain level flight at 1.5 V SR1, where V SR1 is the reference stall speed with the flaps in the approach position, the landing gear retracted, and with the aircraft at its maximum landing weight. The flap position to be used to determine this power setting is that position in which the stall speed, V SR1, does not exceed 110% of the stall speed, V SR0, with the flaps in the most extended landing position.
(b) In each condition required by paragraph (a) of this section, it must be possible to meet the applicable requirements of § 25.203 defined in paragraph 6 of this special condition with:
(c) The following procedures must be used to show compliance with § 25.203 as amended by paragraph 6 of this special condition: (1) Starting at a speed sufficiently above the minimum steady flight speed to ensure that a steady rate of speed reduction can be established, apply the longitudinal control so that the speed reduction does not exceed one knot per second until the control reaches the stop.
6. Characteristics in High Incidence Maneuvers—In lieu of the requirements of § 25.203, the following special condition is issued:
(4) The airplane must not exhibit buffeting of a magnitude or severity that would act as a deterrent to completing the maneuver specified in § 25.201(a) as amended by this special condition.
(d) The rate at which the airplane can be maneuvered from trim speeds associated with scheduled operating speeds, such as V 2 and V REF up to alpha-limit, should not be unduly damped or significantly slower than can be achieved on conventionally controlled transport airplanes.
8. Longitudinal Control—In lieu of the requirements of § 25.145(a), (a)(1) and (b)(6), the following special conditions are issued:
(a) It must be possible, at any point between the trim speed prescribed in § 25.103(b)(6) as amended by this special condition and Vmin, to pitch the nose downward so that the acceleration to this selected trim speed is prompt.
(b) With the landing gear extended, no change in trim control, or exertion of more than 50 pounds control force (representative of the maximum short-term force that can be applied readily by one hand) may be required for the following maneuver: With power off, flaps extended and the airplane trimmed at 1.3 V SR1, obtain and maintain airspeeds between Vmin and either 1.6V SR1 or V FE, whichever is lower.
9. Airspeed Indicating System—In lieu of § 25.1323(c)(1) and (c)(2), the following special conditions are issued: