Final special conditions; request for comments.
These special conditions are issued for the Bombardier Aerospace Models BD-500-1A10 and BD-500-1A11 series airplanes. These airplanes will have novel or unusual design features when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. These design features are electrical and electronic systems that perform critical functions, the loss of which could be catastrophic to the airplane. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for these design features. 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.
This action is effective on Bombardier Aerospace on May 27, 2015. We must receive your comments by June 26, 2015.
Send comments identified by docket number FAA-2015-1819 using any of the following methods:
• Federal eRegulations Portal: Go to http://www.regulations.gov/ and follow the online instructions for sending your comments electronically.
• Mail: Send comments to Docket Operations, M-30, U.S. Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room W12-140, West Building Ground Floor, Washington, DC 20590-0001.
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• Fax: Fax comments to Docket Operations at 202-493-2251.
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FOR FURTHER INFORMATION CONTACT:
Massoud Sadeghi, FAA, Airplane and Flight Crew Interface Branch, ANM-111, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington, 98057-3356; telephone 425-227-2117; facsimile 425-227-1149.
The FAA has determined that notice of, and opportunity for prior public comment on, these special conditions is impracticable because these procedures would significantly delay issuance of the design approval and thus delivery of the affected airplanes. In addition, 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 therefore finds that good cause exists for making these special conditions effective upon publication in the Federal Register .
We invite interested people to take part in this rulemaking by sending written comments, data, or views. The most helpful comments reference a specific portion of the special conditions, explain the reason for any recommended change, and include supporting data.
We will consider all comments we receive by the closing date for comments. We may change these special conditions based on the comments we receive.
On December 10, 2009, Bombardier Aerospace applied for a type certificate for their new Models BD-500-1A10 and BD-500-1A11 series airplanes (hereafter collectively referred to as “CSeries”). The CSeries airplanes are swept-wing monoplanes with an aluminum alloy fuselage, sized for 5-abreast seating. Passenger capacity is designated as 110 for the Model BD-500-1A10 and 125 for the Model BD-500-1A11. Maximum takeoff weight is 131,000 pounds for the Model BD-500-1A10 and 144,000 pounds for the Model BD-500-1A11. The CSeries airplanes will have an electronic flight control system.
Type Certification Basis
Under the provisions of Title 14, Code of Federal Regulations (14 CFR) 21.17, Bombardier Aerospace must show that the CSeries airplanes meet the applicable provisions of 14 CFR part 25 as amended by Amendments 25-1 through 25-129.
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 CSeries airplanes 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.
In addition to the applicable airworthiness regulations and special conditions, the CSeries airplanes 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, and the FAA must issue a finding of regulatory adequacy under section 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 § 11.38, and they become part of the type-certification basis under § 21.17(a)(2).
Novel or Unusual Design Features
The CSeries will incorporate the following novel or unusual design features: Electrical and electronic flight control systems that perform critical functions, the loss of which may result in loss of flight controls and other critical systems and may be catastrophic to the airplane.
The applicable airworthiness regulations do not contain adequate or appropriate safety standards for these design features. 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.
The CSeries airplanes have a fly-by-wire flight control system that requires a continuous source of electrical power in order to maintain an operable flight control system. Section 25.1351(d), Operation without normal electrical power, requires safe operation in visual flight rule (VFR) conditions for at least five minutes after loss of normal electrical power excluding the battery. This rule was structured around a traditional design using mechanical control cables and linkages for flight control. These manual controls allowed the crew to maintain aerodynamic control of the airplane for an indefinite period of time after loss of all electrical power. Under these conditions, a mechanical flight control system provided the crew with the ability to fly the airplane while attempting to identify the cause of the electrical failure, restart engine(s) if necessary, and attempt to re-establish some of the electrical power generation capability.
A critical assumption in § 25.1351(d) is that the airplane is in VFR conditions at the time of the failure. This is not a valid assumption in today's airline operating environment where airplanes fly much of the time in instrument meteorological conditions on air traffic control defined flight paths. Another assumption in the existing rule is that the loss of all normal electrical power is the result of the loss of all engines. The five-minute period in the rule is to allow at least one engine to be restarted following an all-engine power loss in order to continue the flight to a safe landing. However, service experience on airplane models with similar electrical power-system architecture as the CSeries has shown that at least the temporary loss of all electrical power for causes other than all-engine failure is not extremely improbable. In addition, Bombardier is applying for extended operations (ETOPS) type design approval. In order to meet the applicable ETOPS requirements, the electrical power generation system must be able to power all of the electrically powered equipment required for a maximum-length ETOPS diversion.
In order to maintain the same level of safety envisioned by the existing rule with traditional mechanical flight controls in a non-ETOPS operating environment, the CSeries design must not be time-limited in its operation under all reasonably foreseeable conditions, including loss of all normal sources of engine or auxiliary-power-unit (APU)-generated electrical power. Unless Bombardier can show that the non-restorable loss of the engine and APU power sources is extremely improbable, Bombardier must demonstrate that the airplanes can maintain safe flight and landing (including steering and braking on the ground for airplanes using steer/brake-by-wire and/or fly-by-wire speed brake panels) with the use of its emergency/alternate electrical power systems. These electrical power systems, or the minimum restorable electrical power sources, must be able to power loads that are essential for continued safe flight and landing, including those required for a maximum length ETOPS diversion.
As discussed above, these special conditions are applicable to the Model No. BD-500-1A10 and BD-500-1A11 series airplanes. Should Bombardier Aerospace apply at a later date for a change to the type certificate to include another model incorporating the same novel or unusual design feature, the special conditions would apply to that model as well.
This action affects only certain novel or unusual design features on two model series of airplanes. It is not a rule of general applicability.
The substance of these special conditions has been subjected to the notice and comment period in several prior instances and has been derived without substantive change from those previously issued. It is unlikely that prior public comment would result in a significant change from the substance contained herein. Therefore, the FAA has determined that prior public notice and comment are unnecessary and impracticable, and good cause exists for adopting these special conditions upon issuance. The FAA is requesting comments to allow interested persons to submit views that may not have been submitted in response to the prior opportunities for comment described above.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting and recordkeeping requirements.
The authority citation for these special conditions is as follows:
49 U.S.C. 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 Bombardier BD-500-1A10 and BD-500-1A11 series airplanes.
Operation Without Normal Electrical Power
In lieu of Title 14 Code of Federal Regulations (14 CFR) 25.1351(d) the following special conditions apply:
1. Bombardier must show by test or a combination of test and analysis that the airplane is capable of continued safe flight and landing with all normal electrical power sources inoperative, as prescribed by paragraphs 1a and 1b below. For purposes of these special conditions, normal sources of electrical power generation do not include any alternate power sources such as the battery, ram air turbine, or independent power systems such as the flight-control permanent magnet generating system. In showing capability for continued safe flight and landing, Bombardier must account for systems capability, effects on crew workload and operating conditions, and the physiological needs of the flightcrew and passengers for the longest diversion time for which Bombardier is seeking approval.
a. In showing compliance with this requirement, Bombardier must account for common-cause failures, cascading failures, and zonal physical threats.
b. Bombardier may consider the ability to restore operation of portions of the electrical power generation and distribution system if it can be shown that unrecoverable loss of those portions of the system is extremely improbable. The design must provide an alternative source of electrical power for the time required to restore the minimum electrical power generation capability required for safe flight and landing. Bombardier may exclude unrecoverable loss of all engines when showing compliance with this requirement.
2. Regardless of any electrical generation and distribution system recovery capability shown under paragraph 1 of these special conditions, sufficient electrical system capability must be provided to:
a. Allow time to descend, with all engines inoperative, at the speed that provides the best glide distance, from the maximum operating altitude to the top of the engine restart envelope, and
b. Subsequently allow multiple start attempts of the engines and auxiliary power unit (APU). The design must provide this capability in addition to the electrical capability required by existing part 25 requirements related to operation with all engines inoperative.
3. The airplane emergency electrical power system must be designed to supply:
a. Electrical power required for immediate safety, which must continue to operate without the need for crew action following the loss of the normal electrical power, for a duration sufficient to allow reconfiguration to provide a non-time-limited source of electrical power.
b. Electrical power required for continued safe flight and landing for the maximum diversion time.
4. If Bombardier uses APU-generated electrical power to satisfy the requirements of these special conditions, and if reaching a suitable runway for landing is beyond the capacity of the battery systems, then the APU must be able to be started under any foreseeable flight condition prior to the depletion of the battery or the restoration of normal electrical power, whichever occurs first. Flight test must demonstrate this capability at the most critical condition.
a. Bombardier must show that the APU will provide adequate electrical power for continued safe flight and landing.
b. The operating limitations section of the airplane flight manual (AFM) must incorporate non-normal procedures that direct the pilot to take appropriate actions to activate the APU after loss of normal engine-driven generated electrical power.
5. As part of showing compliance with these special conditions, the tests to demonstrate loss of all normal electrical power must also take into account the following:
a. The assumption that the failure condition occurs during night instrument meteorological conditions (IMC) at the most critical phase of the flight, relative to the worst possible electrical power distribution and equipment-loads-demand condition.
b. After the un-restorable loss of normal engine generator power, the airplane engine restart capability is provided and operations continued in IMC.
c. The airplane is demonstrated to be capable of continued safe flight and landing. The length of time must be computed based on the maximum diversion time capability for which the airplane is being certified. Bombardier must account for airspeed reductions resulting from the associated failure or failures.
d. The airplane must provide adequate indication of loss of normal electrical power to direct the pilot to the non-normal procedures, and the operating limitations section of the AFM must incorporate non-normal procedures that will direct the pilot to take appropriate actions.
Issued in Renton, Washington, on May 15, 2015.
Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2015-12698 Filed 5-26-15; 8:45 am]
BILLING CODE 4910-13-P