SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2000-NM-101-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-101-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received a report of the loss of normal electrical power to the essential direct current (DC) bus going undetected by the flight crew. The bus provides power to vital systems, such as aircraft flight displays, communication and navigation equipment, the thrust reverser control, the auxiliary power unit, and fire extinguishing systems. In the event of a problem with the power supply, the bus will automatically switch to the airplane's main batteries to keep these vital systems operating. Operation on battery power is for a short time and is intended only to allow time to land the airplane.

Following a problem with the power supply to the DC essential bus, the flight crew may not be aware of the switch to battery power or the subsequent depletion of the batteries, because the relevant caution lights are located on the overhead instrument panel, rather than in the flight crew's primary line of sight.

This condition, if not corrected, could lead to the flight crew being unaware that depletion of the airplane batteries is occurring, which could result in failure ( printed page 60592) of the vital equipment normally powered by the DC essential bus.

Explanation of Relevant Service Information

The FAA has reviewed and approved Gulfstream Customer Bulletin No. 102A, dated February 1, 2000; Gulfstream Aircraft Service Change No. 327B, dated January 26, 2000; and Aircraft Service Change No. 327B AM1 (Amendment 1), dated August 28, 2000, which describe procedures for modifications to inform the flight crew when the aircraft batteries are powering the essential (DC) bus.

For airplanes having SPZ 8400, the procedures describe modification of the EICAS (Engine Instruments/Caution Advisory System) to replace the existing blue message with an amber indicating light. For airplanes not having the SPZ 8400, the procedures describe modification of the pilot's instrument panel to add an amber indicating light. All airplanes will also have an audible tone when the indicating system is activated. Accomplishment of the actions specified in the customer bulletin and aircraft service changes is intended to adequately address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require accomplishment of the actions specified in the customer bulletin and aircraft service changes described previously.

Cost Impact

The FAA estimates that 292 airplanes of U.S. registry would be affected by this proposed AD and that the average labor rate is $60 per work hour. There will be no charge for required parts for the modification. The cost impact of the proposed AD on U.S. operators depends upon whether the airplane has the SPZ 400, whether the airplane has the production equivalent of Aircraft Service Change No. 327, and whether the operator has performed earlier Aircraft Service Changes No. 327 or No. 327A, as shown in Table 1.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this proposed AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations proposed herein would 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 proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this proposed regulation (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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 draft regulatory 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.

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: