Source: https://www.federalregister.gov/documents/2017/08/14/2017-17072/special-conditions-embraer-sa-model-erj-190-300-airplane-flight-envelope-protection-high-incidence
Timestamp: 2018-03-18 10:49:46
Document Index: 488096452

Matched Legal Cases: ['art 34', 'art 36', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925']

Federal Register :: Special Conditions: Embraer S.A. Model ERJ 190-300 Airplane; Flight Envelope Protection: High Incidence Protection System
37806-37811 (6 pages)
FAA-2017-0316
https://www.federalregister.gov/d/2017-17072 https://www.federalregister.gov/d/2017-17072
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Joe Jacobsen, FAA, Airplane and Flight Crew Interface, ANM-111, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington 98057-3356; telephone 425-227-2011; facsimile 425-227-1320.
In addition, since the substance of these special conditions has been subject to the public comment process in several prior instances with no substantive comments received, the FAA finds it unnecessary to delay the effective date and finds that good cause exists for adopting these special conditions upon publication in the Federal Register.
In addition to the applicable airworthiness regulations and special conditions, the Embraer Model ERJ 190-300 airplane 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.
A high-incidence protection function that limits the angle of attack (AOA) at which the airplane can be flown during normal low-speed operation, and that cannot be overridden by the flightcrew.
The Model ERJ 190-300 airplane design has a complex, full-digital flight-control system, referred to as fly-by-wire (FBW) architecture. This FBW architecture provides closed-loop flight-control laws and multiple protection functions.
The Model ERJ 190-300 airplane is equipped with a high-incidence protection function that limits the angle of attack (AOA) at which the airplane can be flown during normal low-speed operation, and cannot be overridden by the flightcrew. The application of this AOA limit impacts the stall-speed determination, the stall characteristics and stall-warning demonstration, and the longitudinal airplane-handling characteristics. The high-incidence protection function prevents the airplane from stalling at low speeds and, therefore, a stall warning system is backed up during normal flight conditions. If the high-incidence protection function has a failure that is not shown to be extremely improbable, stall warning must be provided in a conventional manner. Also, the flight characteristics at the AOA for VCLmax (AOA at the maximum lift co-efficient and associated speed) must be suitable in the traditional sense. Per 14 CFR 21.16, therefore, special conditions are needed to address the unique features of the high-incidence protection function installed on the Model ERJ 190-300 airplane.
As discussed above, these special conditions are applicable to the Model ERJ 190-300 airplane. Should Embraer apply at a later date for a change to the type certificate to include another model incorporating the same novel or unusual design feature, these special conditions would apply to that model as well.Start Printed Page 37808
Accordingly, pursuant to the authority delegated to me by the Administrator, the following special conditions are issued as part of the type certification basis for the Embraer Model ERJ 190-300 airplane.
The current airworthiness standards do not contain adequate safety standards for the unique features of the high incidence protection system on the Embraer Model ERJ 190-300 airplane. Part I of the following special conditions are issued in lieu of the specified paragraphs of §§ 25.103, 25.145, 25.201, 25.203, 25.207, and 25.1323 of title 14, Code of Federal Regulations (CFR) or in addition to the requirements of § 25.21. Part II are in lieu of the specified paragraphs of §§ 25.103, 25.105, 25.107, 25.121, 25.123, 25.125, 25.143, and 25.207 of title 14 CFR.
The following special conditions are in lieu of §§ 25.103, 25.145(a), 25.145(b)(6), 25.201, 25.203, 25.207, and 25.1323(d) or in addition to the requirements of § 25.21.
The following are terms relating to the novel or unusual design features these special conditions address:
Alpha-limit: The maximum angle of attack at which the airplane stabilizes with the high incidence protection system operating, and the longitudinal control held on its aft stop.
Vmin: The minimum steady flight speed in the airplane configuration under consideration with the high incidence protection system operating. See Part I, section 3 of these special conditions.
Vmin1g: Vmin corrected to 1g conditions. See Part I, section 3 of these special conditions. It is the minimum calibrated airspeed at which the airplane can develop a lift force normal to the flight path and equal to its weight when at an angle of attack not greater than that determined for Vmin.
In lieu of § 25.103, the following requirements apply:
(b) The minimum steady flight speed, Vmin, must be determined if it is used to determine compliance with a required performance standard or other requirements demonstrations in icing or non-icing conditions with:
(c) The 1-g minimum steady flight speed, Vmin 1g, is the minimum calibrated airspeed at which the airplane can develop a lift force (normal to the flight path) equal to its weight, while at an angle of attack not greater than that at which the minimum steady flight speed of subparagraph (a) was determined. It must be determined if it is used to determine compliance with a required performance standard or other requirements demonstrations in icing or non-icing conditions.
(d) The reference stall speed, VSR, is a calibrated airspeed defined by the applicant. VSR may not be less than a 1g stall speed. VSR must be determined in non-icing conditions (and as an option, in icing conditions) and expressed as:
(e) VCLmax is determined with:
(2) The airplane in other respects (such as flaps, landing gear, and ice accretions) in the condition existing in the test or performance standard in which VSR is being used;
(6) The high incidence protection system adjusted or disabled, at the option of the applicant, to allow higher incidence than is possible with the normal production system.
If the capability requirements of the high incidence protection system are successfully demostrated, then the conditions of section 2, “Capability and Reliability of the High Incidence Protection System,” are satisfied. These conditions provide safety equivalent to § 25.207, Stall warning, so the provision of an additional, unique warning device is not required.
Following failures of the high incidence protection system, not shown to be extremely improbable, such that the capability of the system no longer satisfies items (1), (2), and (3) of section 2, “Capability and Reliability of the High Incidence Protection System,” stall warning must be provided and must protect against encountering unacceptable stall characteristics and against encountering stall.
(1) In power off (engine power or thrust at flight idle) straight deceleration not exceeding 1 knot per second to a speed 5 knots or 5 percent calibrated airspeed, whichever is greater, below the warning onset.
(e) In icing conditions stall warning must provide sufficient margin to prevent encountering unacceptable characteristics and encountering stall, in power-off (engine power or thrust at flight idle) straight and turning flight decelerations not exceeding 1 knot per Start Printed Page 37810second, when the pilot starts a recovery maneuver not less than three seconds after the onset of stall warning.
In lieu of §§ 25.201 and 25.203, the following requirements apply:
i. Power off (engine power or thrust at flight idle); and
(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 VSR.
(i) In non-icing conditions, the requirements must also be met with increased rates of entry to the incidence limit, up to the maximum practical entry rate; and
(4) Maneuver with ice accretion prior to operation of the normal anti-ice system. With the ice accretion prior to operation of the normal anti-ice system, the requirements must also be met in deceleration at 1 knot per second. The deceleration must be continued until one second after the activation of the tactile stall warning system or three seconds after reaching full back stick, whichever occurs first. A primary ice detection system must automatically activate the ice protection.
(c) During the maneuvers used to show compliance with paragraphs (a) and (b) above, the airplane must not exhibit dangerous characteristics, and it Start Printed Page 37811must always be possible to reduce angle of attack by conventional use of the controls. The pilot must retain good lateral and directional control, by conventional use of the controls, throughout the maneuver.
In addition to the requirements of § 25.21, the following requirement applies:
For § 25.1323(d), add “From 1.23 VSR to Vmin . . .,” in lieu of, “1.23 VSR to the speed at which stall warning begins . . .,” and, “. . . speeds below Vmin . . .” in lieu of, “. . . speeds below stall warning.”
2. In lieu of § 25.105(a)(2)(i), the following requirement applies:
3. In lieu of § 25.107(c) and (g), the following requirements apply, with additional sections (c′) and (g′):
Takeoff speeds:
4. In lieu of §§ 25.121(b)(2)(ii)(A), 25.121(c)(2)(ii)(A), and 25.121(d)(2)(ii), the following requirements apply:
(d)(2) The requirements of subparagraph (d)(1) of this paragraph must be met: (ii) In icing conditions with the approach ice accretion defined in appendix C, in a configuration corresponding to the normal all-engines-operating procedure in which Vmin 1g for this configuration does not exceed 110% of the Vmin 1g for the related all-engines-operating landing configuration in icing, with a climb speed established with normal landing procedures, but not more than 1.4 VSR (VSR determined in non-icing conditions).
5. In lieu of § 25.123(b)(2)(i), the following requirements apply:
6. In lieu of §§ 25.125(b)(2)(ii)(B) and 25.125(b)(2)(ii)(C), the following requirements apply:
(C) 1.17 Vmin 1g.
7. In lieu of § 25.143(j)(1), the following requirement applies:
(1) The airplane is controllable in a pull-up maneuver up to 1.5 g load factor or lower if limited by angle of attack protection; and
[FR Doc. 2017-17072 Filed 8-11-17; 8:45 am]