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 certain Honeywell IC-600 integrated avionics computers was published in the Federal Register on June 3, 1998 (63 FR 30155). That action proposed to require modification of the integrated avionics computers.
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.
Request to Limit Applicability
One commenter requests that Learjet Model 45 airplanes be removed from the applicability of the proposed rule. The commenter indicates that there was only one Learjet Model 45 airplane with the suspect Honeywell IC-600 integrated avionics computer that received a standard certificate of airworthiness, and that airplane has been modified in accordance with the proposed rule.
The FAA concurs with the commenter s request that the Learjet Model 45 airplanes be removed from the applicability of the final rule. This decision is based on supporting documentation that there was only one Learjet Model 45 airplane with the suspect IC-600, and a modified IC-600 was installed on that airplane before delivery to the customer. Furthermore, Learjet has incorporated the required modifications into production. The part numbers related to these airplanes will be removed from the appropriate sections in the final rule. The Summary and Applicability sections, as well as paragraph (b) of the final rule, have been revised accordingly.
Request to Reduce Compliance Time and Revise the Airplane Flight Manual
One commenter requests that the compliance time for the modification in the proposed rule be reduced from 6 months to 30 days so that the unsafe condition is addressed in a more timely manner. The commenter also requests that a temporary revision to the FAA-approved Airplane Flight Manual(AFM) be issued in the interim to alert flightcrews of the potential hazards if the electronic flight instrument system fails. The commenter states that this is necessary because the unsafe condition exists today and the flightcrews may be unaware of the possibility of this potentially catastrophic condition.
The FAA does not concur with the commenter s request. In developing an appropriate compliance time, the FAA considered the safety implications, parts availability, and normal maintenance schedules. Further, the compliance time of 6 months was established with the operator s, the manufacturer s, and FAA s concurrence. The FAA also has determined that, without prior notice and opportunity for public comment, a reduction in the compliance time is not appropriate. In light of these factors, and in consideration of the amount of time that has already elapsed since issuance of the proposed rule, the FAA has determined that further delay of this final rule is not warranted. However, if additional data are presented that would justify a reduction in the compliance time, the FAA may consider further rulemaking on this issue.
With regard to the commenter s request for an AFM revision, the FAA has considered the potential hazard for temporary loss of flight guidance and does not consider that hazard to be catastrophic. The flightcrew s ability to use the standby instruments during the 30-second rebuild of the display will allow them continued operational safety. Additionally, it was determined that at no time did the display present any hazardously misleading information. Therefore, the FAA does not find it appropriate to require a revision of the AFM. No change to the final rule is necessary in this regard.
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 neither increase the economic burden on any operator nor increase the scope of the AD.
Cost Impact
There are approximately 37 airplanes of the affected design in the worldwide fleet. The FAA estimates that 19 airplanes of U.S. registry will be affected by this proposed AD. It will take approximately 2 work hours per airplane to accomplish the required modification at an average labor rate of $60 per work hour. Required parts will be supplied by the manufacturer at no cost to operators. Based on these figures, the cost impact of the modification required by this AD on U.S. operators is estimated to be $2,280, or $120 per airplane.
The cost impact figure discussed above is based on 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 substantialdirect 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 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: