Discussion
What caused this AD? AD 92-01-02 , Amendment 39-39-8125 (56 FR 65824, December 19, 1991), currently requires you to accomplish the following on certain Fairchild SA226 and SA227 series airplanes:
- modify the parking brake system; and
- inspect (repetitively) certain landing gear brake assemblies.
The inspection requirements of AD 92-01-02 only apply to airplanes equipped with B.F. Goodrich landing gear brake assemblies, part number 2-1203-3. The FAA has received service reports on B.F. Goodrich landing gear brake assemblies, part numbers 2-1203 and 2-1203-01, that indicate these brake assemblies should also be inspected for wear.
Has FAA taken any action to this point? We issued a proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to certain Fairchild SA226 and SA227 series airplanes. This proposal published in the Federal Register as a notice of proposed rulemaking (NPRM) on February 16, 2000 (65 FR 7794). The NPRM proposed to supersede AD 92-01-02, Amendment 398125, by retaining the modification and inspection requirements of AD 92-01-02, and would incorporate the additional landing gear brake assemblies previously referenced.
What is the potential impact if FAA took no action? These actions are necessary to prevent wheel brake system malfunctions. If we did not take action, this could result in a fire in the brake area.
Was the public invited to comment? The FAA encouraged interested persons to participate in the making of this amendment. The following presents the comments received on the proposal and FAA's response to each comment:
Comment Issue No. 1: Incorrect Part Number Referenced
What is the Commenters' Concern? Two commenters state that FAA incorrectly referenced in several places the part number (P/N) 2-1203-1 B.F. Goodrich landing gear brake assemblies as P/N 2-1203-01.
What is FAA's Response to the Concern? We concur and have corrected all reference to this part number in the final rule.
Comment Issue No. 2: Change the Wording in the AD
What is the Commenter's Concern? One commenter requests that FAA revise the last sentence in paragraph 3 of the Discussion section in the NPRM to indicate that our intent is to reduce the wear and clearance limits, not focus on the inspection. The commenter states that because all brake assemblies are inspected for wear and clearance per the aircraft maintenance manual, the emphasis of the AD should be to reduce the maximum allowed clearance.
What is FAA's Response to the Concern? We agree with the proposed wording change and will incorporate it into the final rule as appropriate. We also concur that the focus should be on reducing the maximum allowed clearance. However, the AD must also emphasize the inspection since one of the main actions of the AD is to repetitively inspect and conduct measurements of the brake wear and clearance limits. Comment Issue No. 3: Service Difficulty Reports
What is the Commenters' Request? One commenter requests copies of the service difficulty reports on the P/N 2-1203 landing gear brake assemblies.
What is FAA's Response to the Request? You may obtain service difficulty reports from:
Regulatory Support Division, AFS-600
Federal Aviation Administration (FAA)
P.O. Box 25082 Oklahoma City, OK 73125
Telephone: (405) 954-6501
Facsimile: (405) 954-4104
Comment Issue No. 4: Apply the AD to Brake Assemblies Modified by a Rapco Parts Manufacture Approval (PMA)
What is the Commenters' Concern? One commenter states that, as written, the proposed AD does not apply to B.F. Goodrich brake assemblies that have been modified with Rapco PMA parts. The commenter requests that FAA change the proposed AD to reflect these parts.
What is FAA's Response to the Concern? We concur that the NPRM, as written, may not communicate that the action should also affect B.F. Goodrich brake assemblies modified with Rapco PMA parts. FAA policy is to not reference specific equivalent PMA parts in AD's. If the PMA parts are not equivalent and the unsafe condition applies specifically to these PMA parts, we will write the AD against these parts. However, we generally include a statement of "or FAA-approved equivalent part number(s)" after the referenced part number to account for PMA equivalent parts. The FAA inadvertently left this phrase out of the NPRM, and will add it to the final rule accordingly. If these Rapco PMA parts are installed, then the actions of this AD will apply because the parts are an FAA-approved equivalent to the B.F. Goodrich brake assemblies.
Comment Issue No. 5: The Cost Impact is Incorrect Because FAA Does not Take Into Account the Reduced Life of the Brake Linings
What is the Commenters' Concern? One commenter states that FAA did not take into account the effect the reduced life of the brake linings have on the cost impact of the proposed AD. We infer that the commenter wants us to change the cost impact to reflect this effect.
What is FAA's Response to the Concern? We concur that the reduced allowable wear life of the B.F. Goodrich brake assemblies will present a cost impact. However, we are unable to determine these associated costs because we cannot predict the usage rate of the Fairchild SA226 and SA227 series airplane fleet. Therefore, we are not changing the AD as a result of this comment.
Comment Issue No. 6: The Proposed Compliance Time Does not Account for the Reduced Wear and Clearance Limits
What is the Commenters' Concern? One commenter states that FAA did not take into account the effect that the reduced wear and clearance limits would have when establishing the compliance times. The commenter suggests inspection of the brake assemblies every 50 landings because the brake life will be reduced 23.4 percent and the average life will be approximately6 months of service.
What is FAA's Response to the Concern? We partially concur with the commenter's assessment of the reduced brake life. Assuming a nominal adjustment brake clearance of .0175 inches, we calculate the reduction in brake wear life to 17.7 percent instead of 23.4 percent when the maximum clearance is reduced from .300 inches to .250 inches.
The repetitive inspection compliance time interval will remain at 250 hours time-in-service (TIS), unless the clearance is .200 inches or more, but less than .250 inches. If the clearance is in this range, you would have to inspect at intervals of 75 hours TIS until the brake assembly is replaced (when the maximum clearance is .250 inches or more).
Comment Issue No.7: Certain Aspects of the Plain Language Writing Style are not Appropriate for AD's
What is the Commenters' Concern? One commenter provides feedback to FAA on its initiative to improve the writing style used in regulatory documents. The initiative is based on a Presidential memorandum of June 1, 1998, which requires federal agencies to communicate more clearly with the public.
What is FAA's Response to the Concern? We appreciate the feedback on our initiative to better communicate with those affected by airworthiness directives. We will consider the specific ideas of the commenter, along with those that others submitted on other AD actions, in determining what changes or improvements are needed in the way we draft AD's.
The FAA's Determination
What is FAA's Final Determination on this Issue? We carefully reviewed all available information related to the subject presented above and determined that air safety and the public interest require the adoption of the rule as proposed except for the changes discussed above. These changes provide the intent that was proposed in the NPRM for correcting the unsafe condition and do not impose any additional burden than what was intended in the NPRM.
Are there differencesbetween this AD and the service information? B.F. Goodrich Service Letter No. 1498, dated October 26, 1989, specifies maximum clearance brake wear limits of .300-inch for the B.F. Goodrich landing gear brake assemblies, part numbers 2-1203 and 2-1203-01. This AD will establish these limits at .250-inch to coincide with the wear limits on the part number 2-1203-03 landing gear brake assemblies.
Cost Impact
How many airplanes does the proposed AD impact? The FAA estimates that 330 airplanes in the U.S. registry will be affected by this AD.
What is the cost impact of the initial inspection on owners/operators of the affected airplanes? We estimate that it will take approximately 6 workhours per airplane to accomplish the modification and initial inspection, and that the average labor rate is approximately $60 an hour. Parts to accomplish the modification cost approximately $500 per airplane. Based on these figures, the total cost impact of this AD on U.S. operators isestimated to be $283,800, or $860 per airplane.
What about the cost of repetitive inspections? The figures above only take into account the cost of the initial inspection and do not take into account the cost of repetitive inspections. The FAA has no way of determining how many repetitive inspections each owner/operator of the affected airplanes will incur.
What is the cost if I already accomplished the initial inspection and modification as required by AD 92-01-02? The only impact for those airplane owners/operators who already complied with both the initial inspection and modification requirements of AD 92-01-02 will be the cost of the repetitive inspections. The only difference between this AD and AD 92-01-02 is the addition (to the inspection requirement) of the B.F. Goodrich landing gear brake assemblies, part numbers 2-1203 and 2-1203-01.
Regulatory Impact
Does this AD impact various entities? The regulations adopted herein will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132.
Does this AD involve a significant rule or regulatory action? For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A copy of the final evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption "ADDRESSES".
Listof Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by Reference, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
39.13 [Amended]
2. FAA amends Section 39.13 by removing Airworthiness Directive (AD) 92-01-02, Amendment 398125 (56 FR 65824, December 19, 1991), and by adding a new AD to read as follows: