Discussion
What Events Have Caused This AD?
The FAA received a report of an accident involving a Fairchild Model SA226-TC airplane where the flight crew lost control of the airplane at low altitude during the final approach for landing. Prior to the accident, the flight crew reported a loss of hydraulic pressure and a fire on the left side of the airplane.
Investigation of this accident indicates the following:
--The flight crew applied right rudder power during the takeoff roll to compensate for a dragging and overheated left wheel brake and then raised the landing gear into the left wheel well;
--The overheated left wheel brake ignited the tires and the hydraulic fluid; and
--The resultant fire burned the rubber fuel crossover hose and resulted in fuel leakage with a consequent fuel fire.
The accident investigation shows that the brake shuttle valve may have caused the left wheel brake to drag and overheat.
Has FAATaken 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 Aircraft SA226 and SA227 series airplanes. This proposal was published in the Federal Register as a supplemental notice of proposed rulemaking (NPRM) on December 5, 2000 (65 FR 75883). The supplemental NPRM proposed to require you to replace the brake shuttle valves with parts of improved design (except on airplanes with an anti-skid/power brake system); install a shield over the hydraulic lines; and replace the rubber fuel hose with a metal device on certain SA226 series airplanes.
What Is the Potential Impact if FAA Took No Action?
Original design brake shuttle valves, if not replaced with improved design valves, could cause the wheel brakes to drag and overheat. This could result in hydraulic or fuel line damage if the overheated brake assembly is retracted into the main wheel wells. A consequent fire could occur if the hydraulic or fuel lines ruptured.
Was the Public Invited To Comment?
The FAA encouraged interested persons to participate in the making of this amendment. The following presents the comment received on the proposal and FAA's response to this comment:
Comment Disposition
What Is the Commenter's Concern?
The commenter suggests that the cause of the wheel brake system malfunction may not be related to the brake shuttle valve. The commenter references an incident on a SA226 airplane relative to a dragging wheel brake that was traced to the master cylinder internal relief valve. The FAA infers that the commenter would like us to continue to investigate this issue.
What Is FAA's Response to the Concern?
After thorough investigation of all available information, we determined that the cause of this unsafe condition is related to the brake shuttle valve. The FAA welcomes comments and suggestions such as those made by the commenter. In fact, we have determined that the master cylinder relief valve may have been the cause of other main gear brake incidents. We issued a notice of proposed rulemaking (NPRM) (Docket No. 2001-CE-17-AD), which proposes these brake master cylinders be replaced with new or overhauled units. This NPRM was published in the Federal Register on August 21, 2001 (66 FR 43814).
We will continue to investigate any other potential causes for the dragging brakes on the SA226 and SA227 airplanes.
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 minor editorial corrections. We determined that these minor corrections:
--Will not change the meaning of the AD; and
--Will not add any additional burden upon the public than was already proposed.
Cost Impact
HowMany Airplanes Does This AD Impact?
We estimate that this AD affects 258 airplanes in the U.S. registry.
What Is the Cost Impact of This AD on Owners/Operators of the Affected Airplanes?
We estimate the following costs to accomplish the replacement and installation:
SA226 Series Airplanes
Labor cost
Parts cost
Total cost on U.S. operators
65 workhours x $60 per hour = $3,900.
$3,431 per airplane.
$7,331 per airplane x 258 = $1,891,398.
SA227 Series Airplanes
Labor cost
Parts cost
Total cost on U.S. operators
55 workhours x $60 per hour = $3,300.
$1,369 per airplane.
$4,669 per airplane x 258 = $1,204,602.
Compliance Time of This AD
What Is the Compliance Time of This AD?
The compliance time of this AD is at whichever of the following that occurs later:
--Within 500 hours time-in-service (TIS) after the effective date of this AD; or
--Within 6 months after the effective date of this AD
Why Is the Compliance Time of This AD Presented in Both Hours TIS and Calendar Time?
The affected airplanes are used in both general aviation and commuter operations. Those commuter operators may accumulate 500 hours TIS on the airplane in less than 2 months and many owners have numerous affected airplanes in their fleets. We have determined that the dual compliance time:
--Gives all owners/operators of the affected airplanes adequate time to schedule and accomplish the actions in this AD; and
--Ensures that the unsafe condition referenced in this AD will be corrected within a reasonable time period without inadvertently grounding any of the affected airplanes
Flexibility Determination and Analysis
What Are the Requirements of the Regulatory Flexibility Act?
The Regulatory Flexibility Act of 1980 was enacted by Congress to assure that small entities are not unnecessarily or disproportionately burdened by government regulations. This Act establishes "as principle of regulatory issuance that agencies shall endeavor, consistent with the objectives of the rule and of applicable statutes, to fit regulatory and informational requirements to the scale of the businesses, organizations, and governmental jurisdictions subject to regulation." To achieve this principle, the Act requires agencies to solicit and consider flexible regulatory proposals and to explain the rationale for their actions. The Act covers a wide range of small entities, including small businesses, not-for-profit organizations, and small governmental jurisdictions.
Agencies must perform a review to determine whether a proposed or final rule will have a significant economic impact on a substantial number of small entities. If the determination is that the rule will, the Agency must prepare a regulatory flexibility analysis as described in the RFA.
However, if an agency determines that a proposed or final rule is not expected to have a significant economic impact on a substantial numberof small entities, section 605(b) of the RFA provides that the head of the agency may so certify and a regulatory flexibility analysis is not required. The certification must include a statement providing the factual basis for this determination, and the reasoning should be clear.
What Is FAA's Determination?
The FAA has determined that this AD could have a significant economic impact on a substantial number of small entities. However, we have determined that we should continue with this action in order to address the unsafe condition and ensure aviation safety.
You may obtain a copy of the complete Regulatory Flexibility Analysis (entitled "Final Regulatory Flexibility Analysis") that was prepared for this AD from the Docket file at the location listed under the ADDRESSES section of this document.
Regulatory Impact
Does This AD Impact Various Entities?
The regulations adopted herein will not have a substantial direct effect on the States, on the relationshipbetween 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) could have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. You may obtain a copy of the complete Regulatory Flexibility Analysis (entitled "Final Regulatory Flexibility Analysis") that was prepared for this AD from the Docket file at the location listed under the ADDRESSES section of this document.
List of 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.
Sec. 39.13 [Amended]
2. FAA amends Sec. 39.13 by adding a new AD to read as follows: