Special Conditions: Bell Textron Inc. Model 525 Helicopter; Fly-By-Wire Flight Control System, 2689-2692 [2022-00862]

Download as PDF Federal Register / Vol. 87, No. 12 / Wednesday, January 19, 2022 / Rules and Regulations authorized to sign and submit the document in electronic format for publication, as an official document of the Department of Energy. This administrative process in no way alters the legal effect of this document upon publication in the Federal Register. List of Subjects in 10 CFR Part 430 Administrative practice and procedure, Confidential business information, Energy conservation, Household appliances, Imports, Incorporation by reference, Intergovernmental relations, Small businesses. Signing Authority This document of the Department of Energy was signed on January 11, 2022, by Kelly J. Speakes-Backman, Principal Deputy Assistant Secretary for Energy Efficiency and Renewable Energy, pursuant to delegated authority from the Secretary of Energy. That document with the original signature and date is maintained by DOE. For administrative purposes only, and in compliance with requirements of the Office of the Federal Register, the undersigned DOE Federal Register Liaison Officer has been Signed in Washington, DC, on January 12, 2022. Treena V. Garrett, Federal Register Liaison Officer, U.S. Department of Energy. For the reasons set forth in the preamble, DOE amends part 430 of chapter II, subchapter D, of title 10 of the Code of Federal Regulations, to read as set forth below: PART 430—ENERGY CONSERVATION PROGRAM FOR CONSUMER PRODUCTS 1. The authority citation for part 430 continues as follows: ■ Authority: 42 U.S.C. 6291–6309; 28 U.S.C. 2461 note. 2. Section 430.32 is amended by: a. Removing paragraph (f)(1)(iii); and b. Revising paragraphs (g)(4) and (h)(3). The revisions read as follows: ■ ■ ■ § 430.32 Energy and water conservation standards and their compliance dates. * * * * * (g) * * * (4) Clothes washers manufactured on or after January 1, 2018, shall have an Integrated Modified Energy Factor no less than, and an Integrated Water Factor no greater than: Integrated modified energy factor (cu.ft./kWh/cycle) Product class (i) Top-loading, Compact (less than 1.6 ft 3 capacity) ............................................................. (ii) Top-loading, Standard (1.6 ft 3 or greater capacity) ........................................................... (iii) Front-loading, Compact (less than 1.6 ft 3 capacity) ......................................................... (iv) Front-loading, Standard (1.6 ft 3 or greater capacity) ....................................................... (h) * * * Integrated water factor (gal/cycle/cu.ft.) 1.15 1.57 1.13 1.84 12.0 6.5 8.3 4.7 (3) Clothes dryers manufactured on or after January 1, 2015, shall have a combined energy factor no less than: Combined energy factor (lbs/kWh) Product class (i) Vented Electric, Standard (4.4 ft 3 or greater capacity) .................................................................................................. (ii) Vented Electric, Compact (120V) (less than 4.4 ft 3 capacity) ....................................................................................... (iii) Vented Electric, Compact (240V) (less than 4.4 ft 3 capacity) ...................................................................................... (iv) Vented Gas .................................................................................................................................................................... (v) Ventless Electric, Compact (240V) (less than 4.4 ft 3 capacity) .................................................................................... (vi) Ventless Electric, Combination Washer-Dryer .............................................................................................................. * * * * * BILLING CODE 6450–01–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 29 jspears on DSK121TN23PROD with RULES1 [Docket No. FAA–2021–0065; Special Conditions No. 29–054–SC] Special Conditions: Bell Textron Inc. Model 525 Helicopter; Fly-By-Wire Flight Control System Federal Aviation Administration (FAA), DOT. ACTION: Final special conditions. AGENCY: 16:00 Jan 18, 2022 These special conditions are issued for the Bell Textron Inc. (Bell) Model 525 helicopter. This helicopter will have a novel or unusual design feature associated with a fly-by-wire (FBW) flight control system (FCS). The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards. DATES: Effective February 18, 2022. FOR FURTHER INFORMATION CONTACT: John VanHoudt, FAA, Dynamic Systems Section, AIR–627, Technical Innovation Policy Branch, Policy and Innovation SUMMARY: [FR Doc. 2022–00833 Filed 1–18–22; 8:45 am] VerDate Sep<11>2014 2689 Jkt 256001 PO 00000 Frm 00017 Fmt 4700 Sfmt 4700 3.73 3.61 3.27 3.30 2.55 2.08 Division, Aircraft Certification Service, 10101 Hillwood Parkway, Fort Worth, TX 76177–1524; telephone and fax 817– 222–5193; email John.G.Van.Houdt@ FAA.Gov. SUPPLEMENTARY INFORMATION: Background On December 15, 2011, Bell applied for a type certificate for a new transport category helicopter, designated as the Model 525, under Title 14, Code of Federal Regulations (CFR) part 29. Bell applied for multiple extensions, with the most recent occurring on November 12, 2020. The date of the updated type certification basis is December 31, 2016, based upon the applicant’s proposed type certificate issuance date of December 31, 2021. The Model 525 is a E:\FR\FM\19JAR1.SGM 19JAR1 jspears on DSK121TN23PROD with RULES1 2690 Federal Register / Vol. 87, No. 12 / Wednesday, January 19, 2022 / Rules and Regulations medium twin-engine rotorcraft. The design maximum takeoff weight is 20,500 pounds, with a maximum capacity of 19 passengers and a crew of two. The Bell Model 525 helicopter will be equipped with a four axis full authority digital FBW FCS that provides for aircraft control through pilot input and coupled flight director modes. The design of the Bell Model 525 FBW controls, which provides no direct hydro-mechanical linkage between the primary cockpit flight controls or inceptors and the main and tail rotor actuators, is a first for commercial rotorcraft use. Therefore, the regulations do not contain adequate or appropriate safety standards for this new design feature. The rotorcraft industry is producing new generations of helicopters, and gradually increasing size, speed, load capacity, and technical sophistication. In recent years, an accelerated trend has occurred using rotorcraft for a wide range of commercial and industrial applications. This has resulted in increased complexity of modern control systems and increased use of automation in flight control systems, including the implementation of advanced flight control systems such as FBW FCS. Section 29.671(c), which provides requirements for transport category rotorcraft control systems, does not contain adequate or appropriate safety standards for this new design feature. Section 29.671(c) requires, in part, a means to allow the pilot to determine that full control authority is available prior to flight. This command control authority is typically achieved by verifying movement of the control quadrant through an unassisted mechanical pilot-initiated manipulation of the primary flight controls prior to flight. Although this approach does not guarantee that 100% maximum control movement of the flight controls has been achieved prior to flight, it has been deemed appropriate for mechanical flight control systems. Unlike traditional mechanical flight control systems, the FBW FCS reduces the opportunity for jamming of the flight controls due to mechanical bind, improper servo adjustment resulting from faulty maintenance, or presence of a foreign object in the control mechanism that will impair safety. This reduced exposure for jams is due to the replacement of the mechanical linkages between the primary cockpit flight controls or inceptors and the main and tail rotor actuators with digital signal processing wiring. However, the FBW FCS does increase the potential for VerDate Sep<11>2014 16:00 Jan 18, 2022 Jkt 256001 latent failures or faults that could impair full control authority, unless a means exists to ensure the FBW FCS is fully functional and free of control authority impairment prior to flight. A FBW system may have the ability to verify full control authority without having to move the primary flight controls. Although part 29 does not contain adequate or appropriate safety standards for this novel or unusual design feature, 14 CFR 25.671, amendment 25–23, provides these requirements for transport category airplanes. Accordingly, these special conditions are based on § 25.671 to provide requirements for a FBW FCS on the Bell Model 525 helicopter. Section 25.671(c) provides the same level of safety as intended by § 29.671(c) when employing a FBW FCS by including requirements for jamming and failure analysis. These special conditions require a comprehensive safety analysis of the aircraft’s FBW FCS to include failures due to command logic (software), mechanical and electronic interfaces to other systems, jamming, and maintenance. Therefore, in conjunction with § 29.671(a) and (b), these special conditions incorporate provisions from § 25.671(c) to establish a level of safety equivalent to that established in the regulations. Type Certification Basis Under the provisions of 14 CFR 21.17, Bell must show that the Model 525 helicopter meets the applicable provisions of part 29, as amended by Amendments 29 through 55 thereto. The Bell Model 525 certification basis date is December 31, 2016. If the Administrator finds that the applicable airworthiness regulations (i.e., part 29) do not contain adequate or appropriate safety standards for the Bell Model 525 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 or similar novel or unusual design feature, the special conditions would also apply to the other model under § 21.101. In addition to the applicable airworthiness regulations and special conditions, the Bell Model 525 helicopter must comply with the noise certification requirements of 14 CFR part 36, and the FAA must issue a finding of regulatory adequacy under § 611 of Public Law 92–574, the ‘‘Noise Control Act of 1972.’’ PO 00000 Frm 00018 Fmt 4700 Sfmt 4700 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). Novel or Unusual Design Features The Bell Model 525 helicopter will incorporate the following novel or unusual design features: A FBW FCS. This new design feature has no direct hydro-mechanical linkage between the primary cockpit flight controls or inceptors and the main and tail rotor actuators, thereby eliminating the more complex elements of either a manual movement of the controls by the pilot, or another manual means. Discussion These special conditions require that a means be available to show full control authority for all powered control systems. These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards. Discussion of Comments The FAA issued Notice of Proposed Special Conditions No. 29–054–SC for the Bell Model 525 helicopter, which published in the Federal Register on January 29, 2021 (86 FR 7516). The FAA received one response, from the European Union Aviation Safety Agency (EASA). The FAA proposed the special conditions, which are based on current § 25.671(c), in lieu of § 29.671(c). EASA requested the FAA explain its rationale for replacing § 29.671(c), which requires a means to allow either full movement of all primary flight controls or a determination by the pilot that full control authority is available prior to flight. EASA stated that although FBW reduces the risk of jamming, it does not alleviate the need to allow checking the full control movement prior to flight and thus a pre-flight check is still necessary. The FAA is not replacing the requirement for a pre-flight check. Instead, these special conditions include a requirement for a comprehensive safety analysis to ensure the FBW FCS is fully functional and free of control authority impairment prior to flight. The comprehensive safety analysis should address failures due to command logic (software), mechanical and electronic interfaces to other systems, jamming, and maintenance. The safety analysis should also identify the existence of any latent faults. E:\FR\FM\19JAR1.SGM 19JAR1 jspears on DSK121TN23PROD with RULES1 Federal Register / Vol. 87, No. 12 / Wednesday, January 19, 2022 / Rules and Regulations Therefore, the means to ensure the FBW FCS is fully functional and free of control authority impairment prior to flight is based on the results of the comprehensive safety analysis. The means to ensure the safety objective of the special conditions is met may consist of design, analysis, test, built in test, and limited pre-flight checks. EASA noted the proposed special conditions, although derived from § 25.671(c), are not aligned with EASA’s latest Certification Specifications (CS) 25.671 (Amendment 24). Under § 21.16, special conditions prescribed by the FAA must establish a level of safety equivalent to that established in the FAA’s existing regulations. Accordingly, the FAA based these special conditions on 14 CFR 25.671(c) and not on EASA’s certification specifications. EASA requested the FAA clarify its use of the term ‘‘continued safe flight and landing’’ used in the proposed special conditions. EASA stated the term has a specific definition for flight control failures on large airplanes and asked whether the FAA will use a consistent definition for failure conditions under § 29.1309. EASA also asked whether the FAA will provide a definition of ‘‘continued safe flight and landing’’ in the context of flight control failures. Advisory Circular 29–2C, Certification of Transport Category Rotorcraft (AC 29–2C), contains a definition for ‘‘continued safe flight and landing.’’ The FAA plans to use this definition for the purposes of these special conditions. EASA stated the proposed special conditions introduce the term ‘‘normal flight envelope,’’ which is not present in EASA’s CS 29 regulation. EASA questioned whether it is relevant only to the Bell Model 525 and whether it means the same as ‘‘operating’’ envelope. When § 25.671 was incorporated, the ‘‘normal flight envelope’’ was the aircraft approved operating limitations contained in the aircraft flight manual. This proposed special condition has the same intent. In order to provide clarity and consistency in the language between this special condition and § 29.672, the wording will be revised to approved operating limitations. EASA asked what the FAA means by the proposed requirement that ‘‘probable failures have only minor effects.’’ Specifically, EASA asked whether a probable failure is greater than 1E¥5 per flight hour and whether ‘‘no safety effect’’ would be a noncompliance. In AC 29–2C, the upper part of the range previously applied to the term VerDate Sep<11>2014 16:00 Jan 18, 2022 Jkt 256001 ‘‘probable’’ has been redefined as ‘‘reasonably probable.’’ Accordingly, the FAA has revised these special conditions by replacing ‘‘probable’’ with ‘‘reasonably probable.’’ As provided in AC 29–2C, reasonably probable events are based on a probability on the order of between 10¥3 to 10¥5. If a failure is classified as ‘‘no safety effect,’’ then no further showing of compliance would be required. EASA requested the FAA change the language in paragraphs (1) and (2) of the proposed special conditions to reference failures as defined in § 29.671(c)(3). EASA states its suggested language will avoid a gap between EASA CS 29.671(c)(1) and 29.671(c)(3). The FAA agrees and made the suggested change in the special conditions. EASA stated that if the FAA’s special conditions have a no single failure criterion under § 29.1309, then jams under § 29.671(c)(3) may need to be excluded. EASA referenced CS 25.1309 (Amendment 24) for no single failure. EASA is correct; there is no criteria for single failure in § 29.1309. As such, the FAA has removed the ‘‘single’’ descriptor from the special conditions language to be consistent with § 29.1309 safety objectives. The FAA does not agree that jams under § 29.671(c)(3) need to be excluded. Any failure condition that can be shown to be extremely improbable isn’t limited by failures that occur from a single source. EASA stated that using language from § 25.671(c), which is applicable to transport category airplanes, is overly ambitious for rotorcraft. EASA asked several hypothetical questions concerning how an applicant would show compliance and requested the FAA provide further guidance. Section 29.671(c), which these special conditions replace as a certification requirement for the Model 525, requires either a means to allow full control movement of the primary flight controls prior to flight or a means that will allow the pilot to determine that full control authority is available prior to flight. The language utilized from § 25.671(c) for these special conditions ensures verification of the control authority prior to flight via a comprehensive safety analysis. This analysis is necessary to address failures that could not be detected by full control movement of the digital primary flight controls. EASA requested the FAA clarify whether § 29.691 is sufficient for an FBW system or whether specific guidance is needed for FBW flight controls after a power failure at entry into and during autorotation. PO 00000 Frm 00019 Fmt 4700 Sfmt 4700 2691 The requirements in § 29.691, and the accompanying guidance in AC 29–2C, are sufficient for an FBW system. Section 29.691 requires that the flight control design allow rapid entry into autorotation after a power failure. AC 29–2C provides that applicants may comply with this rule through an evaluation as part of the Type Inspection Authorization test program. EASA requested the FAA clarify the meaning of ‘‘normally encountered’’ in paragraph (3) of the proposed special conditions. Specifically, EASA asked whether there are jams that are not considered normal and are therefore excluded from the assessment. EASA further noted that the flight conditions listed in paragraph (3) of the proposed special conditions are contrary to the maneuvers required by §§ 29.141 and 29.143. The FAA intended these special conditions to address jams encountered during any flight condition including transitions between flight conditions. The FAA has revised paragraph (3) accordingly. EASA requested the FAA clarify the relationship between the proposed special conditions and § 29.685(a), which addresses flight control jamming. EASA noted the approach in § 29.685(a) is different from the one proposed in the special conditions, as § 29.685(a) requires the design of the control system to prevent jamming. EASA states the proposed special conditions would not provide credit for jamming that may result in a condition where continued safe flight is guaranteed. Section 29.685(a) contains a design requirement for mechanical controls and is limited in scope. These special conditions are broader and include FBW primary flight controls that did not exist when § 29.685 was promulgated in 1964. Regarding EASA’s statement about credit, paragraph (3) of these special conditions require reducing jamming in any phase of flight to a level capable of continued safe flight and landing. Applicability These special conditions are applicable to the Bell Model 525 helicopter. Should Bell 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. Conclusion This action affects only a certain novel or unusual design feature on the Bell Model 525 helicopter. It is not a rule of general applicability. E:\FR\FM\19JAR1.SGM 19JAR1 2692 Federal Register / Vol. 87, No. 12 / Wednesday, January 19, 2022 / Rules and Regulations List of Subjects in 14 CFR Part 29 ACTION: Final rule; request for comments. Aircraft, Aviation safety, Reporting, and recordkeeping requirements. SUMMARY: Authority Citation The authority citation for these special conditions is as follows: Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701–44702, 44704. The Special Conditions 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 Bell Textron Inc. Model 525 helicopter. Unless otherwise stated, the following special conditions will be used in lieu of § 29.671(c). The rotorcraft must be shown by analysis and tests, to be capable of continued safe flight and landing after any of the following failures or jamming in the flight control system for any speed or altitude within the approved operating limitations, without requiring exceptional piloting skill or strength. Reasonably probable failures must have only minor effects. (1) Any failure, excluding a jam as listed in paragraph (3). (2) Any combination of failures not shown to be extremely improbable, excluding a jam as listed in paragraph (3). (3) Any jam in a control position encountered during any flight condition, including transitions, within the approved operating limitations, unless the jam is shown to be extremely improbable, or can be alleviated. Issued in Kansas City, Missouri, on January 12, 2022. Patrick Mullen, Manager, Technical Innovation Policy Branch, Policy and Innovation Division, Aircraft Certification Service. [FR Doc. 2022–00862 Filed 1–18–22; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 jspears on DSK121TN23PROD with RULES1 [Docket No. FAA–2022–0004; Project Identifier AD–2022–00036–T; Amendment 39–21913; AD 2022–02–16] RIN 2120–AA64 Airworthiness Directives; The Boeing Company Airplanes Federal Aviation Administration (FAA), DOT. AGENCY: VerDate Sep<11>2014 16:00 Jan 18, 2022 Jkt 256001 The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 787–8, 787–9, and 787–10 airplanes. This AD was prompted by a determination that radio altimeters cannot be relied upon to perform their intended function if they experience interference from wireless broadband operations in the 3.7–3.98 GHz frequency band (5G C-Band), and a recent determination that, during landings, as a result of this interference, certain airplane systems may not properly transition from AIR to GROUND mode when landing on certain runways, resulting in degraded deceleration performance and longer landing distance than normal due to the effect on thrust reverser deployment, speedbrake deployment, and increased idle thrust. This AD requires revising the limitations and operating procedures sections of the existing airplane flight manual (AFM) to incorporate limitations prohibiting certain landings and the use of certain minimum equipment list (MEL) items, and to incorporate operating procedures for calculating landing distances, when in the presence of 5G C-Band interference as identified by Notices to Air Missions (NOTAMs). The FAA is issuing this AD to address the unsafe condition on these products. DATES: This AD is effective January 19, 2022. The FAA must receive comments on this AD by March 7, 2022. ADDRESSES: You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods: • Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions for submitting comments. • Fax: 202–493–2251. • Mail: U.S. Department of Transportation, Docket Operations, M– 30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue SE, Washington, DC 20590. • Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. Examining the AD Docket You may examine the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA–2022–0004; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, any comments received, and PO 00000 Frm 00020 Fmt 4700 Sfmt 4700 other information. The street address for the Docket Operations is listed above. FOR FURTHER INFORMATION CONTACT: Dean Thompson, Senior Aerospace Engineer, Systems and Equipment Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax: 206–231–3165; email: dean.r.thompson@faa.gov. SUPPLEMENTARY INFORMATION: Background In March 2020, the United States Federal Communications Commission (FCC) adopted final rules authorizing flexible use of the 3.7–3.98 GHz band for next generation services, including 5G and other advanced spectrum-based services.1 Pursuant to these rules, CBand wireless broadband deployment is permitted to occur in phases with the opportunity for operations in the lower 0.1 GHz of the band (3.7–3.8 GHz) in certain markets as early as January 19, 2022. This AD refers to ‘‘5G C-Band’’ interference, but wireless broadband technologies, other than 5G, may use the same frequency band.2 These other uses of the same frequency band are within the scope of this AD since they would introduce the same risk of radio altimeter interference as 5G C-Band. The radio altimeter is an important aircraft instrument, and its intended function is to provide direct heightabove-terrain/water information to a variety of aircraft systems. Commercial aviation radio altimeters operate in the 4.2–4.4 GHz band, which is separated by 0.22 GHz from the C-Band telecommunication systems in the 3.7– 3.98 GHz band. The radio altimeter is more precise than a barometric altimeter and for that reason is used where aircraft height over the ground needs to be precisely measured, such as autoland, manual landings, or other low altitude operations. The receiver on the radio altimeter is typically highly accurate, however it may deliver erroneous results in the presence of outof-band radio frequency emissions from other frequency bands. The radio altimeter must detect faint signals reflected off the ground to measure altitude, in a manner similar to radar. Out-of-band signals could significantly degrade radio altimeter functions during critical phases of flight, if the altimeter is unable to sufficiently reject those signals. 1 The FCC’s rules did not make C-Band wireless broadband available in Alaska, Hawaii, and the U.S. Territories. 2 The regulatory text of the AD uses the term ‘‘5G C-Band’’ which, for purposes of this AD, has the same meaning as ‘‘5G’’, ‘‘C-Band’’ and ‘‘3.7–3.98 GHz.’’ E:\FR\FM\19JAR1.SGM 19JAR1

Agencies

[Federal Register Volume 87, Number 12 (Wednesday, January 19, 2022)]
[Rules and Regulations]
[Pages 2689-2692]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-00862]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 29

[Docket No. FAA-2021-0065; Special Conditions No. 29-054-SC]


Special Conditions: Bell Textron Inc. Model 525 Helicopter; Fly-
By-Wire Flight Control System

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for the Bell Textron Inc. 
(Bell) Model 525 helicopter. This helicopter will have a novel or 
unusual design feature associated with a fly-by-wire (FBW) flight 
control system (FCS). The applicable airworthiness regulations do not 
contain adequate or appropriate safety standards for this design 
feature. These special conditions contain the additional safety 
standards that the Administrator considers necessary to establish a 
level of safety equivalent to that established by the existing 
airworthiness standards.

DATES: Effective February 18, 2022.

FOR FURTHER INFORMATION CONTACT: John VanHoudt, FAA, Dynamic Systems 
Section, AIR-627, Technical Innovation Policy Branch, Policy and 
Innovation Division, Aircraft Certification Service, 10101 Hillwood 
Parkway, Fort Worth, TX 76177-1524; telephone and fax 817-222-5193; 
email [email protected].

SUPPLEMENTARY INFORMATION:

Background

    On December 15, 2011, Bell applied for a type certificate for a new 
transport category helicopter, designated as the Model 525, under Title 
14, Code of Federal Regulations (CFR) part 29. Bell applied for 
multiple extensions, with the most recent occurring on November 12, 
2020. The date of the updated type certification basis is December 31, 
2016, based upon the applicant's proposed type certificate issuance 
date of December 31, 2021. The Model 525 is a

[[Page 2690]]

medium twin-engine rotorcraft. The design maximum takeoff weight is 
20,500 pounds, with a maximum capacity of 19 passengers and a crew of 
two.
    The Bell Model 525 helicopter will be equipped with a four axis 
full authority digital FBW FCS that provides for aircraft control 
through pilot input and coupled flight director modes. The design of 
the Bell Model 525 FBW controls, which provides no direct hydro-
mechanical linkage between the primary cockpit flight controls or 
inceptors and the main and tail rotor actuators, is a first for 
commercial rotorcraft use. Therefore, the regulations do not contain 
adequate or appropriate safety standards for this new design feature.
    The rotorcraft industry is producing new generations of 
helicopters, and gradually increasing size, speed, load capacity, and 
technical sophistication. In recent years, an accelerated trend has 
occurred using rotorcraft for a wide range of commercial and industrial 
applications. This has resulted in increased complexity of modern 
control systems and increased use of automation in flight control 
systems, including the implementation of advanced flight control 
systems such as FBW FCS.
    Section 29.671(c), which provides requirements for transport 
category rotorcraft control systems, does not contain adequate or 
appropriate safety standards for this new design feature. Section 
29.671(c) requires, in part, a means to allow the pilot to determine 
that full control authority is available prior to flight. This command 
control authority is typically achieved by verifying movement of the 
control quadrant through an unassisted mechanical pilot-initiated 
manipulation of the primary flight controls prior to flight. Although 
this approach does not guarantee that 100% maximum control movement of 
the flight controls has been achieved prior to flight, it has been 
deemed appropriate for mechanical flight control systems.
    Unlike traditional mechanical flight control systems, the FBW FCS 
reduces the opportunity for jamming of the flight controls due to 
mechanical bind, improper servo adjustment resulting from faulty 
maintenance, or presence of a foreign object in the control mechanism 
that will impair safety. This reduced exposure for jams is due to the 
replacement of the mechanical linkages between the primary cockpit 
flight controls or inceptors and the main and tail rotor actuators with 
digital signal processing wiring. However, the FBW FCS does increase 
the potential for latent failures or faults that could impair full 
control authority, unless a means exists to ensure the FBW FCS is fully 
functional and free of control authority impairment prior to flight. A 
FBW system may have the ability to verify full control authority 
without having to move the primary flight controls.
    Although part 29 does not contain adequate or appropriate safety 
standards for this novel or unusual design feature, 14 CFR 25.671, 
amendment 25-23, provides these requirements for transport category 
airplanes. Accordingly, these special conditions are based on Sec.  
25.671 to provide requirements for a FBW FCS on the Bell Model 525 
helicopter. Section 25.671(c) provides the same level of safety as 
intended by Sec.  29.671(c) when employing a FBW FCS by including 
requirements for jamming and failure analysis. These special conditions 
require a comprehensive safety analysis of the aircraft's FBW FCS to 
include failures due to command logic (software), mechanical and 
electronic interfaces to other systems, jamming, and maintenance. 
Therefore, in conjunction with Sec.  29.671(a) and (b), these special 
conditions incorporate provisions from Sec.  25.671(c) to establish a 
level of safety equivalent to that established in the regulations.

Type Certification Basis

    Under the provisions of 14 CFR 21.17, Bell must show that the Model 
525 helicopter meets the applicable provisions of part 29, as amended 
by Amendments 29 through 55 thereto. The Bell Model 525 certification 
basis date is December 31, 2016.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., part 29) do not contain adequate or appropriate 
safety standards for the Bell Model 525 because of a novel or unusual 
design feature, special conditions are prescribed under the provisions 
of Sec.  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 or similar 
novel or unusual design feature, the special conditions would also 
apply to the other model under Sec.  21.101.
    In addition to the applicable airworthiness regulations and special 
conditions, the Bell Model 525 helicopter must comply with the noise 
certification requirements of 14 CFR part 36, and the FAA must issue a 
finding of regulatory adequacy under Sec.  611 of Public Law 92-574, 
the ``Noise Control Act of 1972.''
    The FAA issues special conditions, as defined in 14 CFR 11.19, in 
accordance with Sec.  11.38, and they become part of the type-
certification basis under Sec.  21.17(a)(2).

Novel or Unusual Design Features

    The Bell Model 525 helicopter will incorporate the following novel 
or unusual design features: A FBW FCS.
    This new design feature has no direct hydro-mechanical linkage 
between the primary cockpit flight controls or inceptors and the main 
and tail rotor actuators, thereby eliminating the more complex elements 
of either a manual movement of the controls by the pilot, or another 
manual means.

Discussion

    These special conditions require that a means be available to show 
full control authority for all powered control systems.
    These special conditions contain the additional safety standards 
that the Administrator considers necessary to establish a level of 
safety equivalent to that established by the existing airworthiness 
standards.

Discussion of Comments

    The FAA issued Notice of Proposed Special Conditions No. 29-054-SC 
for the Bell Model 525 helicopter, which published in the Federal 
Register on January 29, 2021 (86 FR 7516). The FAA received one 
response, from the European Union Aviation Safety Agency (EASA).
    The FAA proposed the special conditions, which are based on current 
Sec.  25.671(c), in lieu of Sec.  29.671(c). EASA requested the FAA 
explain its rationale for replacing Sec.  29.671(c), which requires a 
means to allow either full movement of all primary flight controls or a 
determination by the pilot that full control authority is available 
prior to flight. EASA stated that although FBW reduces the risk of 
jamming, it does not alleviate the need to allow checking the full 
control movement prior to flight and thus a pre-flight check is still 
necessary.
    The FAA is not replacing the requirement for a pre-flight check. 
Instead, these special conditions include a requirement for a 
comprehensive safety analysis to ensure the FBW FCS is fully functional 
and free of control authority impairment prior to flight. The 
comprehensive safety analysis should address failures due to command 
logic (software), mechanical and electronic interfaces to other 
systems, jamming, and maintenance. The safety analysis should also 
identify the existence of any latent faults.

[[Page 2691]]

Therefore, the means to ensure the FBW FCS is fully functional and free 
of control authority impairment prior to flight is based on the results 
of the comprehensive safety analysis. The means to ensure the safety 
objective of the special conditions is met may consist of design, 
analysis, test, built in test, and limited pre-flight checks.
    EASA noted the proposed special conditions, although derived from 
Sec.  25.671(c), are not aligned with EASA's latest Certification 
Specifications (CS) 25.671 (Amendment 24).
    Under Sec.  21.16, special conditions prescribed by the FAA must 
establish a level of safety equivalent to that established in the FAA's 
existing regulations. Accordingly, the FAA based these special 
conditions on 14 CFR 25.671(c) and not on EASA's certification 
specifications.
    EASA requested the FAA clarify its use of the term ``continued safe 
flight and landing'' used in the proposed special conditions. EASA 
stated the term has a specific definition for flight control failures 
on large airplanes and asked whether the FAA will use a consistent 
definition for failure conditions under Sec.  29.1309. EASA also asked 
whether the FAA will provide a definition of ``continued safe flight 
and landing'' in the context of flight control failures.
    Advisory Circular 29-2C, Certification of Transport Category 
Rotorcraft (AC 29-2C), contains a definition for ``continued safe 
flight and landing.'' The FAA plans to use this definition for the 
purposes of these special conditions.
    EASA stated the proposed special conditions introduce the term 
``normal flight envelope,'' which is not present in EASA's CS 29 
regulation. EASA questioned whether it is relevant only to the Bell 
Model 525 and whether it means the same as ``operating'' envelope.
    When Sec.  25.671 was incorporated, the ``normal flight envelope'' 
was the aircraft approved operating limitations contained in the 
aircraft flight manual. This proposed special condition has the same 
intent. In order to provide clarity and consistency in the language 
between this special condition and Sec.  29.672, the wording will be 
revised to approved operating limitations.
    EASA asked what the FAA means by the proposed requirement that 
``probable failures have only minor effects.'' Specifically, EASA asked 
whether a probable failure is greater than 1E-5 per flight 
hour and whether ``no safety effect'' would be a noncompliance.
    In AC 29-2C, the upper part of the range previously applied to the 
term ``probable'' has been redefined as ``reasonably probable.'' 
Accordingly, the FAA has revised these special conditions by replacing 
``probable'' with ``reasonably probable.'' As provided in AC 29-2C, 
reasonably probable events are based on a probability on the order of 
between 10-3 to 10-5. If a failure is classified 
as ``no safety effect,'' then no further showing of compliance would be 
required.
    EASA requested the FAA change the language in paragraphs (1) and 
(2) of the proposed special conditions to reference failures as defined 
in Sec.  29.671(c)(3). EASA states its suggested language will avoid a 
gap between EASA CS 29.671(c)(1) and 29.671(c)(3).
    The FAA agrees and made the suggested change in the special 
conditions.
    EASA stated that if the FAA's special conditions have a no single 
failure criterion under Sec.  29.1309, then jams under Sec.  
29.671(c)(3) may need to be excluded. EASA referenced CS 25.1309 
(Amendment 24) for no single failure.
    EASA is correct; there is no criteria for single failure in Sec.  
29.1309. As such, the FAA has removed the ``single'' descriptor from 
the special conditions language to be consistent with Sec.  29.1309 
safety objectives. The FAA does not agree that jams under Sec.  
29.671(c)(3) need to be excluded. Any failure condition that can be 
shown to be extremely improbable isn't limited by failures that occur 
from a single source.
    EASA stated that using language from Sec.  25.671(c), which is 
applicable to transport category airplanes, is overly ambitious for 
rotorcraft. EASA asked several hypothetical questions concerning how an 
applicant would show compliance and requested the FAA provide further 
guidance.
    Section 29.671(c), which these special conditions replace as a 
certification requirement for the Model 525, requires either a means to 
allow full control movement of the primary flight controls prior to 
flight or a means that will allow the pilot to determine that full 
control authority is available prior to flight. The language utilized 
from Sec.  25.671(c) for these special conditions ensures verification 
of the control authority prior to flight via a comprehensive safety 
analysis. This analysis is necessary to address failures that could not 
be detected by full control movement of the digital primary flight 
controls.
    EASA requested the FAA clarify whether Sec.  29.691 is sufficient 
for an FBW system or whether specific guidance is needed for FBW flight 
controls after a power failure at entry into and during autorotation.
    The requirements in Sec.  29.691, and the accompanying guidance in 
AC 29-2C, are sufficient for an FBW system. Section 29.691 requires 
that the flight control design allow rapid entry into autorotation 
after a power failure. AC 29-2C provides that applicants may comply 
with this rule through an evaluation as part of the Type Inspection 
Authorization test program.
    EASA requested the FAA clarify the meaning of ``normally 
encountered'' in paragraph (3) of the proposed special conditions. 
Specifically, EASA asked whether there are jams that are not considered 
normal and are therefore excluded from the assessment. EASA further 
noted that the flight conditions listed in paragraph (3) of the 
proposed special conditions are contrary to the maneuvers required by 
Sec. Sec.  29.141 and 29.143.
    The FAA intended these special conditions to address jams 
encountered during any flight condition including transitions between 
flight conditions. The FAA has revised paragraph (3) accordingly.
    EASA requested the FAA clarify the relationship between the 
proposed special conditions and Sec.  29.685(a), which addresses flight 
control jamming. EASA noted the approach in Sec.  29.685(a) is 
different from the one proposed in the special conditions, as Sec.  
29.685(a) requires the design of the control system to prevent jamming. 
EASA states the proposed special conditions would not provide credit 
for jamming that may result in a condition where continued safe flight 
is guaranteed.
    Section 29.685(a) contains a design requirement for mechanical 
controls and is limited in scope. These special conditions are broader 
and include FBW primary flight controls that did not exist when Sec.  
29.685 was promulgated in 1964. Regarding EASA's statement about 
credit, paragraph (3) of these special conditions require reducing 
jamming in any phase of flight to a level capable of continued safe 
flight and landing.

Applicability

    These special conditions are applicable to the Bell Model 525 
helicopter. Should Bell 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.

Conclusion

    This action affects only a certain novel or unusual design feature 
on the Bell Model 525 helicopter. It is not a rule of general 
applicability.

[[Page 2692]]

List of Subjects in 14 CFR Part 29

    Aircraft, Aviation safety, Reporting, and recordkeeping 
requirements.

Authority Citation

    The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701-44702, 44704.

The Special Conditions

    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 Bell Textron Inc. Model 525 
helicopter. Unless otherwise stated, the following special conditions 
will be used in lieu of Sec.  29.671(c).
    The rotorcraft must be shown by analysis and tests, to be capable 
of continued safe flight and landing after any of the following 
failures or jamming in the flight control system for any speed or 
altitude within the approved operating limitations, without requiring 
exceptional piloting skill or strength. Reasonably probable failures 
must have only minor effects.
    (1) Any failure, excluding a jam as listed in paragraph (3).
    (2) Any combination of failures not shown to be extremely 
improbable, excluding a jam as listed in paragraph (3).
    (3) Any jam in a control position encountered during any flight 
condition, including transitions, within the approved operating 
limitations, unless the jam is shown to be extremely improbable, or can 
be alleviated.

    Issued in Kansas City, Missouri, on January 12, 2022.
Patrick Mullen,
Manager, Technical Innovation Policy Branch, Policy and Innovation 
Division, Aircraft Certification Service.
[FR Doc. 2022-00862 Filed 1-18-22; 8:45 am]
BILLING CODE 4910-13-P