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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 2000-NM-144-AD] 
          - RIN 2120-AA64 

# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Notice of proposed rulemaking (NPRM). 

# SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Gulfstream Model G-1159A (G-III) series airplanes. This proposal would require modification of the master caution panel by installing an additional legend labeled “BATT ON BUS” and associated wiring to indicate when the airplane batteries are powering the direct current (DC) essential bus. This action is necessary to ensure that the flight crew is aware that an electrical system failure has occurred and that the main airplane batteries are powering the essential DC bus. If the flight crew is unaware of this situation, action to stop the depletion of the airplane batteries will not be taken and critical equipment, such as communications and navigation equipment, could fail. This action is intended to address the identified unsafe condition. 

# DATES:

Comments must be received by November 27, 2000. 

# ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-144-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 2000-NM-144-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text. 

The service information referenced in the proposed rule may be obtained from Gulfstream Aerospace Corporation, P.O. Box 2206, M/S D-10, Savannah, Georgia 31402-9980. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, suite 450, Atlanta, Georgia. 

# FOR FURTHER INFORMATION CONTACT:

Neil Berryman, Aerospace Engineer, Systems and Flight Test Branch, ACE-116A, FAA, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, suite 450, Atlanta, Georgia 30349; telephone (770) 703-6066; fax (770) 703-6097. 

# 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       ( print page 60594)                          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-144-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-144-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. 

## Discussion 

Power to vital systems (such as aircraft flight displays, communication and navigation equipment, and fire extinguishing systems) is provided through the direct current (DC) essential bus. In the event of a problem with the power supply, the bus will automatically switch to battery power 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 and are not in the primary line-of-sight of the flight crew. The FAA has one report of a loss of electrical power to the DC essential bus being undetected by a Gulfstream G-IV flight crew, because they did not see the caution light. The DC essential bus on certain Model G-IV series airplanes is almost identical to that on the affected Model G-III series airplanes. Therefore, those Model G-III series airplanes may be subject to the same unsafe condition revealed on the Model G-IV series airplanes. 

If the flight crew could not see the caution light, the flight crew could be unaware that an electrical system failure has occurred and that the airplane main batteries were powering the essential DC bus. If the flight crew were unaware of this situation, action to stop the depletion of the airplane batteries would not be taken and critical equipment, such as communications and navigation equipment, could fail. 

## Explanation of Relevant Service Information 

The FAA has reviewed and approved Gulfstream Customer Bulletin No. 149, dated March 23, 1999, which describes procedures for adding an additional legend to the master caution panel in the primary view of the flight crew to inform them when batteries are powering the DC essential bus. The customer bulletin also describes modification of wiring in the pilot's and copilot's junction boxes, the auxiliary power relay box, and the power distribution box. Gulfstream Customer Bulletin No. 149, dated March 23, 1999, references Gulfstream Aircraft Service Change No. 294, dated February 3, 1999, as the appropriate source of service information for accomplishment of the modification. Accomplishment of the actions specified in the customer bulletin and aircraft service change 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 Gulfstream customer bulletin and aircraft service change described previously, except as discussed below. 

## Differences Between the Proposal and the Customer Bulletin 

Operators should note that, although Customer Bulletin No. 149 recommends accomplishing the modification within 24 months after the release of the customer bulletin, the FAA has determined that an interval of 24 months would not address the identified unsafe condition in a timely manner. In developing an appropriate compliance time for this proposed AD, the FAA considered not only the manufacturer's recommendation, but also the degree of urgency associated with addressing the subject unsafe condition and the average utilization of the affected fleet. In light of these factors, the FAA finds a 12-month compliance time for initiating the proposed actions to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety. 

## Cost Impact 

There are approximately 198 airplanes of the affected design in the worldwide fleet. The FAA estimates that 144 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 55 work hours per airplane to accomplish the proposed modification, and that the average labor rate is $60 per work hour. Required parts would cost approximately $1,587 per airplane. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $703,728, or $4,887 per airplane. 

The cost impact figure discussed above is 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                           ( print page 60595)                        location provided under the caption                     **ADDRESSES.**

# List of Subjects in 14 CFR Part 39

      - Air transportation
      - Aircraft
      - Aviation safety
      - Safety

## 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: 

# 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 

2. Section 39.13 is amended by adding the following new airworthiness directive:

**Gulfstream Aerospace Corporation:**                                 Docket 2000-NM-144-AD.                             

*Applicability:*                                 Model G-1159A (G-III) series airplanes, serial numbers 357 and 402 through 498 inclusive, certificated in any category.                             

# Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

*Compliance:*                                 Required as indicated, unless accomplished previously.                             

To prevent the flight crew from being unaware that an electrical system failure has occurred and that the airplane main batteries are powering the direct current (DC) essential bus, accomplish the following: 

(a) Within 12 months after the effective date of this AD, modify the wiring in the pilot's and co-pilot's junction boxes, the auxiliary power relay box, the power distribution box, and the master caution panel, in accordance with Gulfstream Customer Bulletin No. 149, dated March 23, 1999, and Gulfstream Aircraft Service Change No. 294, dated February 3, 1999. 

## Alternative Methods of Compliance 

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Atlanta Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Atlanta ACO. 

# Note 2:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Atlanta ACO.

## Special Flight Permits 

(c) Special flight permits may be issued in accordance with §§ 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. 

Issued in Renton, Washington, on October 4, 2000. 

Donald L. Riggin, 

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. 

[FR Doc. 00-26094 Filed 10-11-00; 8:45 am] 

BILLING CODE 4910-13-P