A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to all Shorts Model SD3-30 and SD3-60 series airplanes equipped with certain fire extinguishers was published in the Federal Register on January 27, 1997 (62 FR 3832). That action proposed to require replacement of the covers for fire extinguisher adapter assemblies that are installed on certain bulkheads with new covers that swivel to lock the extinguishers in place; and replacement of nozzles and triggers on these fire extinguishers with better fitting nozzles and stronger triggers. It also proposed to require the installation of new fire extinguisher point placards and a revision of the Airplane Flight Manual to instruct the flight crew in the use of the new covers for these adapter assemblies.
Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.
One commenter, an organization representing airline pilots, supports the proposed AD; however, it requests that the FAA implement specific training in the use of critical equipment such as fire extinguishers, including the actual equipment used in the aircraft.
The FAA acknowledges the commenter's concern. The FAA has determined that an unsafe condition exists, and that the actions required by this AD are adequate in order to ensure the continued safety of the affected fleet. While there may be merit to the commenter's suggestion, this AD is not the appropriate context in which to evaluate that suggestion. Since the suggested change would alter the actions currently required by this AD, additional rulemaking would be required. The FAA finds that to delay this action would be inappropriate in light of the identified unsafe condition. No change to this final rule is necessary.
The manufacturer of the affected airplanes notes that replacement of the discharge head assembly in accordance with Fire Fighting Enterprises (U.K.) Ltd. Service Bulletin 26-107, Revision 1, dated November 2, 1992, includes replacement of the trigger as also required by the company's Service Bulletin 26-108, dated September 1992. Both service bulletins are cited as the appropriate sources of service information in paragraph (c) of the proposed AD. The commenter requests that this information be provided in the AD so that operators would not rework the fire extinguisher head per Service Bulletin 26-107 (which would require the installation of a new trigger in accordance with Service Bulletin 26-108), only to discover that both actions could be accomplished by replacing the discharge head.
The FAA concurs that some confusion could result with regard to the current wording contained in paragraph (c)(1) of this final rule. Therefore, the FAA has changed paragraph (c)(1) to read, "Install a chamfered nozzle on the discharge head assembly of each fire extinguisher and add a new trigger by replacing * * *." That change, together with the clarification contained in the service bulletin, should preclude any confusion in that regard.
The same commenter requests that an inspection procedure be provided in order to determine whether the trigger has actually been replaced in accordance with Service Bulletin 26-108. The commenter states that paragraph 3.A.(3)(h) of Service Bulletin 26-107, Revision 1, requires that the fire extinguisher trigger be marked with part number BA22988-3 after rework of the nozzle chamfer. The commenter further asserts that, since effectivity of Service Bulletin 26-108 does not include discharge head part number BA22988-3, maintenance personnel may assume that, following accomplishment of Service Bulletin 26-107(and re-marking of the part to BA22988-3), replacement of the trigger in accordance with Service Bulletin 26-108 is not necessary.
The FAA does not concur that an inspection should be added to this AD. Contrary to the commenter's assertion, Service Bulletin 26-107 requires that the reworked discharge head, not the trigger itself, be marked with part number BA22988-3. In any event, the AD requires replacement of the trigger with the stronger trigger, either through accomplishment of Service Bulletin 26-107, Revision 1, or 26-108, regardless of the part number marking on the fire extinguisher discharge head. However, replacement of the trigger is required only if such replacement has not been accomplished prior to the effective date of the AD. Investigation of airplane maintenance records may be necessary to confirm whether the stronger trigger has been installed. If there are no records showing that it has already been installed, the stronger trigger must be installed in accordance with this AD.
The commenter also provided corrected information concerning the address from which the referenced service bulletins may be obtained andthe cost of parts needed for compliance. The correct address is shown above under the heading ADDRESSES, and the cost impact information presented below reflects the corrected information concerning the cost of parts. The cost impact information also reflects changes that have occurred in the number of affected U.S.-registered airplanes since the notice of proposed rulemaking was published.
Conclusion
After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither significantly increase the economic burden on any operator nor increase the scope of the AD.
Cost Impact
The FAA estimates that 33 Model SD3-30 series airplanes of U.S. registry will be affected by this AD. For these airplanes, it will take approximately 9 work hours per airplane to accomplish the requiredactions on airplanes with only a forward baggage bay, and 14 work hours per airplane to accomplish the required actions on airplanes with forward and aft baggage bays. The average labor rate is $60 per work hour. Required parts will cost approximately $735 per airplane. Based on these figures, the cost impact of the AD on U.S. operators of Model SD3-30 series airplanes is estimated to be between $42,075 and $51,975, or between $1,275 and $1,575 per airplane.
The FAA estimates that 52 Model SD3-60 series airplanes of U.S. registry will be affected by this AD. For these airplanes, it will take approximately 12 work hours per airplane to accomplish the required actions, at an average labor rate of $60 per work hour. Required parts will cost approximately $776 per airplane. Based on these figures, the cost impact of the AD on U.S. operators of Model SD3-60 series airplanes is estimated to be $77,792, or $1,496 per airplane.
The cost impact figures discussed above are basedon assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.
Regulatory Impact
The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
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 substantialnumber of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to 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. Section 39.13 is amended by adding the following new airworthiness directive: