Source: https://www.federalregister.gov/documents/2002/05/21/02-12608/special-conditions-airbus-industrie-model-a340-500-600-airplanes-ground-loads-and-conditions-for
Timestamp: 2017-09-22 19:43:34
Document Index: 100186516

Matched Legal Cases: ['art 25', 'art 25', 'art 25', 'art 25', '§\u200921', '§\u200925', '§\u200925', '§\u200925', 'art 25']

A Rule by the Federal Aviation Administration on 05/21/2002
35715-35722 (8 pages)
Special Conditions No. 25-200-SC
https://www.federalregister.gov/d/02-12608 https://www.federalregister.gov/d/02-12608
These special conditions are issued for the Airbus Industrie Model A340-500 and -600 airplanes. These airplanes will have a novel or unusual design feature when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. This design feature is associated with the landing gear, in the form of a four-wheeled center landing gear, installed under the fuselage, which functions like a main landing gear in all respects, including the ability to brake. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These proposed 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.
On November 14, 1996, Airbus Industrie applied for an amendment to Start Printed Page 35716U.S. type certificate (TC) A43NM to include the new models A340-500 and -600. These models are derivatives of the A340-300, which is approved under the same TC.
Under the provisions of 14 CFR 21.101, Airbus Industrie must show that the Model A340-500 and -600 airplanes meet the applicable provisions of the regulations incorporated by reference in TC A43NM or the applicable regulations in effect on the date of application for the change to the type certificate. The regulations incorporated by reference in the type certificate are commonly referred to as the “original type certification basis.” The regulations incorporated by reference in TC A43NM are 14 CFR part 25 effective February 1, 1965, including Amendments 25-1 through 25-63 and Amendments 25-64, 25-65, 25-66, and 25-77, with certain exceptions that are not relevant to these proposed special conditions.
In addition, if the regulations incorporated by reference do not provide adequate standards with respect to the change, the applicant must comply with certain regulations in effect on the date of application for the change. The FAA has determined that the Model A340-500 and -600 airplanes must be shown to comply with Amendments 25-1 through 25-91,with certain FAA-allowed reversions for specific part 25 regulations to the part 25 amendment levels of the original type certification basis.
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 Airbus Industrie Model A340-500 and -600 airplanes because of a novel or unusual design feature, special conditions are prescribed under the provisions of 14 CFR 21.16.
The Airbus Model A340-500 and -600 airplanes will incorporate the following novel or unusual design feature: a four-wheel center landing gear with braking ability.
The basic A340 included a two-wheel center landing gear which did not have brakes. The purpose of the center landing gear was to assist the main landing gear during ground handling conditions for heavy airplane weights. This center landing gear was not intended for energy absorption during landing, even if it could participate in the impact under certain conditions. Therefore, to provide additional taxi, takeoff, and landing criteria for this arrangement, Special Conditions 25-ANM-69 were issued.
The Model A340-500 and -600 airplanes have a four-wheel center landing gear which functions in all respects like a main landing gear, including braking capabilities. Because the speeds and weights of the Model A340-500 and -600 airplanes are greater than that of the basic A340, redesign of the center landing gear was necessary. As a result, the current rules, applying to the original two-wheel center landing gear, are inadequate.
Notice of proposed special conditions No. 25-02-03-SC for the Airbus Industrie Model A340-500 and -600 airplanes was published in the Federal Register on March 20, 2002 (67 FR 12903). No comments were received, and the special conditions are adopted as proposed.
As discussed above, these special conditions are applicable to the Airbus Model A340-500 and -600 airplanes. Should Airbus Industries 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 under the provisions of § 21.101(a)(1).
Under standard practice, the effective date of final special conditions would be 30 days after the date of publication in the Federal Register; however, as the certification date for the Airbus Model A340-500 and A340-600 airplanes is imminent, the FAA finds that good cause exists to make these special conditions effective upon issuance.
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 Airbus Model A340-500 and A340-600 airplanes.
The following special conditions are issued in lieu of the previously issued special conditions, “Ground Load Conditions for Center Landing Gear,” recorded as item 10 of Special Conditions: Airbus Industrie Model A340 Series Airplanes [Docket No. NM-75, Special Conditions No. 25-ANM-69]:
1. Ground Load Conditions for Center Landing Gear. Notwithstanding § 25.477, the requirements of § 25.473 Start Printed Page 35717and §§ 25.479 through 25.485 apply, except as noted:
(i) For static strength substantiation, these loads multiplied by an appropriate factor of safety that is related to the probability of occurrence of the failure are ultimate loads to be considered for design. The factor of safety (F.S.) is defined in Figure 2 as follows:
(3) Warning considerations. For system failure detection and warning, the system must be checked for failure conditions, not extremely improbable, that degrade the structural capability below the level required by part 25 or significantly reduce the reliability of the remaining system. The flightcrew must be made aware of these failures before flight. Certain elements of the control system, such as mechanical and hydraulic components, may use special periodic inspections, and electronic components may use daily checks, in lieu of warning systems to achieve the objective of this requirement. These certification maintenance requirements must be limited to components that are not readily detectable by normal warning systems and where service Start Printed Page 35720history shows that inspections will provide an adequate level of safety.
(4) Dispatch with known failure conditions. If the airplane is to be dispatched in a known system failure condition that affects structural performance, or affects the reliability of the remaining system to maintain structural performance, then the provisions of these special conditions must be met for the dispatched condition and for subsequent failures. Flight limitations and expected operational limitations may be taken into account in establishing Qj as the combined probability of being in the dispatched failure condition and the subsequent failure condition for the safety margins in Figure 3. These limitations must be such that the probability of being in this combined failure state and then subsequently encountering limit load conditions is extremely improbable. No reduction in these safety margins is allowed if the subsequent system failure rate is greater than 10−3 per hour. Figure 3 follows:
[FR Doc. 02-12608 Filed 5-20-02; 8:45 am]