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 Fokker Model F.28 Mark 0070 and 0100 series airplanes was published in the Federal Register on March 15, 1999 (64 FR 12772). That action proposed to require modification of the electrical wiring of the flight warning computer (FWC), and installation of upgraded computer software into the FWC.
Comments Received
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.
Request for Extension of Compliance Time
Two commenters, both operators, raise a concern regarding the necessity to accomplish other modifications prior to or concurrent with accomplishment of the modification described in Fokker Service Bulletin SBF100-31-051, dated August 15, 1998, which is required by paragraph (b) of the proposed AD. One commenter states that the wiring modification described in Fokker Service Bulletin SBF100-78-014, Revision 2, dated May 1, 1999, is necessary prior to or concurrent with accomplishment of SBF100-31-051. Additionally, Service Bulletin SBF100-78-014 specifies that three other service bulletins must be accomplished either prior to or concurrent with SBF100-78-014, including SBF100-78-012 [which is also required by AD 96-26-03, amendment 39-9866 (62 FR 604, January 6, 1997)].
Both commenters state that the labor and costs associated with these additional modifications will require the actions proposed in this AD to be accomplished in conjunction with scheduled heavy maintenance visits, rather than during scheduled overnight maintenance. One commenter states that the compliance threshold should be extended to preclude the additional operational costs associated with removing an airplane from service out of the normally scheduled sequence. The two commenters request thatthe compliance threshold of 18 months for accomplishment of SBF100-31-051 be extended (to 24 months or 30 months after the effective date of the AD) to allow sufficient time for scheduling of the additionally required modifications.
The FAA does not concur. After further discussions with the Rijksluchtvaartdienst (RLD), which is the airworthiness authority for the Netherlands, and the manufacturer, the FAA has determined that such extension of the compliance time would not provide an acceptable level of safety necessary to address the identified unsafe condition. Accomplishment of the modifications specified in the proposed AD, as well as the necessary prior modifications to support the final modification, was found to be necessary in the wake of thrust reverser problems related to a 1996 accident in Brazil.
In developing the proposed compliance time of 18 months, the FAA considered the safety implications, the RLD's and the manufacturer's recommendations, and the availability of required parts. The FAA also considered the fact that Fokker Service Bulletin SBF100-31-051 has been available to all affected operators since August 1998. Therefore, U.S. operators have had time since then to consider initiating those actions, which this AD ultimately mandates. Under the provisions of paragraph (c) of the final rule, however, the FAA may consider requests for adjustments to the compliance time if data are submitted to substantiate that such an adjustment would provide an acceptable level of safety.
Relation of Proposed AD to AD 96-26-03
One commenter states that the proposed AD does not address the necessary modifications (as discussed previously) described in Fokker Service Bulletin SBF100-78-014, which specifies prior accomplishment of Fokker Service Bulletin SBF100-78-012. Since SBF100-78-012 is currently required by AD 96-26-03, the commenter notes that the proposed AD does not provide the necessary relief for the interim conditions when an airplane may not be in the configuration specified by AD 96-26-03 or in full compliance with the proposed new AD. If the required relief is not provided, the commenter states that each operator will be forced to petition the FAA for each variance encountered during the fleet modification program, which will add significant workload for both these operators and the FAA.
The FAA partially concurs. The FAA concurs that AD 96-26-03 currently specifies accomplishment of SBF100-78-012, which is indirectly necessary prior to accomplishment of SBF100-31-051 as required by this proposed AD. However, since issuance of the proposed AD, another proposed AD (reference Rules Docket No. 98-NM-329-AD) has been issued that would supersede AD 96-26-03. That proposed AD would continue to require accomplishment of SBF100-78-012 by March 21, 1997 (the compliance time specified in AD 96-26-03), and would add a requirement for accomplishment of SBF100-78-014 within 18 months after the effective date of that AD. The FAA does not consider that accomplishment of the requirements of these AD's will pose any configuration problems for operators provided the AD's are issued simultaneously, since the compliance times of 18 months would be identical. The FAA will ensure that the AD's are issued simultaneously to avoid the concern expressed by the commenter.
The FAA has added NOTE 4 to the final rule to provide clarification regarding the accomplishment of other modifications prior to accomplishment of SBF100-31-051, as well as related FAA rulemaking actions specified in AD 96-26-03 and Rules Docket No. 98-NM-329-AD.
Request to Remove Spares Paragraph
One commenter states that paragraph (c) of the proposed AD, which specifies that "As of the effective date of this AD, no person shall install on any airplane a flight warning computer (FWC), unless it has been modified in accordance with this AD", is an impossible stipulation. The commenter states that there will be a transition period during which the wiring of some airplanes will not be modified as described in SBF100-78-014. An upgraded FWC cannot be installed in an unmodified airplane, therefore, provisions must be made to allow the installation of an unmodified FWC in an unmodified airplane.
The FAA concurs. The necessary airplane wiring modifications will be accomplished over a period of time and are necessary prior to accomplishment of the FWC modifications required by this AD. Since the modified FWC's cannot be installed in an unmodified airplane, the FAA has deleted the requirement regarding installation of an unmodified FWC by removing this paragraph from the final rule.
Request to Revise Cost Information
One commenter states that the proposed AD does not address the labor and material costs associated with accomplishment of SBF100-78-014. Therefore, the commenter states that an additional 44 work hours and material costs of $7,663 must be added to the projected cost estimates providedin the proposed AD. The FAA does not concur. As stated previously, accomplishment of SBF100-78-014 is proposed as a direct requirement in a separate rulemaking action (reference Rules Docket No. 98-NM-329-AD). Cost estimates associated with that action are provided in that NPRM and therefore are not restated in this AD.
Other Changes Made to the Proposed AD
The FAA has been informed that the manufacturer's address has changed and has revised the AD to provide the correct address for obtaining service information. The FAA also has revised its estimate of the number of affected airplanes from 129 in the proposed AD to 126, and the cost impact information, below, has been revised accordingly.
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 described previously. The FAA has determined that these changes will neitherincrease the economic burden on any operator nor increase the scope of the AD.
Cost Impact
The FAA estimates that 126 airplanes of U.S. registry will be affected by this AD, that it will take approximately 6 work hours per airplane to accomplish the required modification, and that the average labor rate is $60 per work hour. Required parts will cost approximately $93 per airplane. Based on these figures, the cost impact of the modification on U.S. operators is estimated to be $57,078, or $453 per airplane.
It will take approximately 1 work hour per airplane to accomplish the required installation, at an average labor rate of $60 per work hour. Required parts will cost approximately $1,500 per airplane. Based on these figures, the cost impact of the installation on U.S. operators is estimated to be $196,560, or $1,560 per airplane.
The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this ADaction, 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 substantial number of small entities under the criteria of the Regulatory Flexibility Act. A finalevaluation 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: