Source: https://www.federalregister.gov/documents/2014/02/07/2014-02613/special-conditions-bombardier-aerospace-inc-models-bd-500-1a10-and-bd-500-1a11-series-airplanes
Timestamp: 2018-12-11 11:04:54
Document Index: 210196639

Matched Legal Cases: ['art 25', 'art 34', 'art 36', '§\u200925', 'art 25', 'art 25', '§\u200925', '§\u200925', '§\u200925', '§\u200925']

Federal Register :: Special Conditions: Bombardier Aerospace Inc., Models BD-500-1A10 and BD-500-1A11 Series Airplanes; Autobraking System Loads
Special Conditions: Bombardier Aerospace Inc., Models BD-500-1A10 and BD-500-1A11 Series Airplanes; Autobraking System Loads
79 FR 7370
7370-7371 (2 pages)
Docket No. FAA-2013-0942
Special Conditions No. 25-515-SC
FAA-2013-0942
https://www.federalregister.gov/d/2014-02613 https://www.federalregister.gov/d/2014-02613
These special conditions are issued for the Bombardier Aerospace Inc. Models BD-500-1A10 and BD-500-1A11 series airplanes. These airplanes will have novel or unusual design features associated with the autobraking system for use during landing. 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 Start Printed Page 7371equivalent to that established by the existing airworthiness standards.
Mark Freisthler, FAA, Airframe and Cabin Safety Branch, ANM-115 Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington 98057-3356; telephone 425-227-1119; facsimile 425-227-1232.
Under the provisions of Title 14, Code of Federal Regulations (14 CFR) 21.17, Bombardier Inc. must show that the C-series airplanes meet the applicable provisions of part 25, as amended by Amendment 25-1 through 25-129.
In addition to the applicable airworthiness regulations and special conditions, the C-series 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 C-series airplanes will incorporate the following novel or unusual design features: The C-series airplanes will have an autobrake system. This is a pilot-selectable function that allows earlier maximum braking at landing without pilot pedal input. When the autobrake system is armed before landing, it automatically commands maximum braking at main wheels touchdown. Normal procedures remain unchanged and call for manual braking after nose wheel touchdown.
Section 25.493 addresses braked roll loads but does not contain a specific “pitchover” requirement addressing the loading on the nose gear, the nose gear surrounding structure, and the forward fuselage. Moreover, § 25.493 specifies airplane attitudes in accordance with figure 6 of appendix A to part 25, which are level landing attitudes. For airplanes with traditional braking systems, the current ground load requirements are considered adequate for the design of the nose gear and airframe structure. However, the C-Series airplane autobrake system, which could apply maximum braking at the main wheels with the airplane in a tail-down attitude well before the nose touches down, will cause a high nose gear sink rate and potentially higher gear and airframe loads.
Part 25 does not contain adequate requirements to address the potentially higher structural loads that could result from this type of braking system. In addition, the effects on fatigue covered by § 25.571 also need to be considered. Therefore, FAA has determined that additional airworthiness standards are needed for the certification of this unusual design feature. These special conditions propose airworthiness standards for the certification of the C-series airplanes with an autobrake system.
Notice of proposed special conditions No. FAA-2013-0942 for the Bombardier C-series airplanes was published in the Federal Register on November 12, 2013 (78 FR 67321). No comments were received, and the special conditions are adopted as proposed.
This action affects only certain novel or unusual design features on one series of airplanes. It is not a rule of general applicability.
Autobraking System Loads. A landing pitchover condition must be addressed that takes into account the effect of the autobrake system. The airplane is assumed to be at the design maximum landing weight, or at the maximum weight allowed with the autobrake system on. The airplane is assumed to land in a tail-down attitude at the speeds defined by § 25.481. Following main gear contact, the airplane is assumed to rotate about the main gear wheels at the highest pitch rate generated by the autobrake system. This is considered a limit load condition from which ultimate loads must also be determined. Loads must be determined for a critical fuel and payload distribution and centers of gravity. Nose gear loads, as well as airframe loads, must be determined. The airplane must support these loads as described in § 25.305.
In addition to the above airworthiness standards, fatigue loads must also be determined and applied in accordance to § 25.571.
[FR Doc. 2014-02613 Filed 2-6-14; 8:45 am]