AD 98-18-15

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Gulfstream Model G-V series airplanes. This action requires a one-time inspection to measure the clearance between a certain wiring harness and the crew oxygen bottle; corrective actions, if necessary; and eventual relocation of the crew oxygen bottle and rework of the lines and tubing associated with the crew and passenger oxygen bottles. This amendment is prompted by a report indicating that interference between the wiring harness and the crew oxygen bottle was found on a production airplane. The actions specified in this AD are intended to prevent chafing of the wiring harness against the crew oxygen bottle, which could result in electrical shorting and possible fire in the underfloor structure of the airplane.

Final rule; request for comments

98-18-15 GULFSTREAM AEROSPACE CORPORATION: Amendment 39-10731. Docket 98-NM-230-AD.

Applicability: Model G-V series airplanes, serial numbers 501 through 549 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 (c) 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 chafing of a wiring harness against the crew oxygen bottle, which could result in electrical shorting and possible fire in the underfloor structure of the airplane, accomplish the following:

(a) Within 25 flight hours after the effective date of this AD, perform a one-time visual inspection to measure the clearance between the wiring harness located beneath floor board 4C and the crew oxygen bottle and bottle mounting structure, in accordance with Gulfstream Aerospace G-V Alert Customer Bulletin No. 4A, dated July 8, 1998, as revised by Gulfstream Aerospace G-V Alert Customer Bulletin No. 4A, Amendment 1, dated August 10, 1998.

(1) If the clearance is greater than or equal to .250 inch, and if any Teflon sheeting is installed: No further action is required by paragraph (a) of this AD.

(2) If the clearance is greater than or equal to .250 inch, and if no Teflon sheeting is installed: Prior to further flight, install .030-inch Teflon sheeting in accordance with the alert customer bulletin, as revised by Amendment 1.

(3) If the clearance is less than .250 inch, and if any Teflon sheeting is installed: Prior to further flight, inspect the sheeting for evidence of chafing, in accordance with the alert customer bulletin, as revised by Amendment 1.

(i) If no evidence of chafing of the Teflon sheeting is detected, prior to further flight, install .125-inch Teflon sheeting, in accordance with the alert customer bulletin, as revised by Amendment 1.

(ii) If any evidence of chafing of the Teflon sheeting is detected, prior to further flight, remove the Teflon sheeting and inspect the wires to detect evidence of chafing, in accordance with the alert customer bulletin, as revised by Amendment 1; and accomplish the actions specified in either paragraph (a)(4)(i) or (a)(4)(ii), as applicable.

(4) If the clearance is less than .250 inch, and if no Teflon sheeting is installed: Prior to further flight, inspect the wires to detect evidence of chafing, in accordance with the alert customer bulletin, as revised by Amendment 1.

(i) If no evidence of chafing of the wires is detected, prior to further flight, install .125-inch Teflon sheeting in accordance with the alert customer bulletin, as revised by Amendment 1.

(ii) If any evidence of chafing of the wires is detected, prior to further flight, repair in accordance with a method approved by the Manager, Atlanta Aircraft Certification Office (ACO), FAA, Small Airplane Directorate.

(b) Within 150 flight hours after the effective date of this AD, relocate the crew oxygen bottle and rework the lines and tubing associated with the crew and passenger oxygen bottles, in accordance with Gulfstream Aerospace G-V Alert Customer Bulletin No. 4A, dated July 8, 1998, as revised by Gulfstream Aerospace G-V Alert Customer Bulletin No. 4A, Amendment 1, dated August 10, 1998.

NOTE 2: Gulfstream Aerospace G-V Alert Customer Bulletin No. 4A, dated July 8, 1998, as revised by Gulfstream Aerospace G-V Alert Customer Bulletin No. 4A, Amendment 1, dated August 10, 1998, refers to Gulfstream Aerospace Aircraft Service Change No. 059A, dated August 3, 1998, as an additional source of service information for accomplishing the relocation of the crew oxygen bottle.

(c) 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 ACO. 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 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Atlanta ACO.

(d) Special flight permits may be issued in accordance with sections 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.

(e) Except as provided by (a)(4)(ii) of this AD, the actions shall be done in accordance with Gulfstream Aerospace G-V Alert Customer Bulletin No. 4A, dated July 8, 1998, as revised by Gulfstream Aerospace G-V Alert Customer Bulletin No. 4A, Amendment 1, dated August 10, 1998. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Gulfstream Aerospace Corporation, P.O. Box 2206, M/S D-10, Savannah, Georgia 31402-9980. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Small Airplane Directorate, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, suite 450, Atlanta, Georgia; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(f)This amendment becomes effective on September 18, 1998.

The FAA has received a report indicating that interference between a certain wiring harness and the crew oxygen bottle was observed on several production Gulfstream Model G-V series airplanes. Wiring contained in the affected harness, which is located beneath floor board 4C, includes the fuel boost pump power, ground service bus battery power, and three-phase alternating current power for the right battery charger. Interference between the wiring harness and the crew oxygen bottle could result in chafing of the electrical wires and consequent electrical shorting. Due to the proximity of the wiring harness to the oxygen bottle, such electrical shorting, if not prevented, could result in a fire in the underfloor structure of the airplane.

Gulfstream has inspected approximately 10 to 12 in-house airplanes to measure clearance between the wiring harness and crew oxygen bottle. These inspections revealed that, on certain airplanes, the lack of clearancehad been detected during production and protective Teflon sheeting had been installed to prevent chafing. In some cases, evidence of chafing of the Teflon sheeting was observed. However, no chafing of wiring has been detected. It is unknown how many airplanes already have such protective sheeting installed.

Explanation of Relevant Service Information
The FAA has reviewed and approved Gulfstream Aerospace G-V Alert Customer Bulletin No. 4A, dated July 8, 1998, as revised by Gulfstream Aerospace G-V Alert Customer Bulletin No. 4A, Amendment 1, dated August 10, 1998. That alert customer bulletin and amendment describe procedures for a one-time visual inspection to measure the clearance between the wiring harness located beneath floor board 4C and the crew oxygen bottle and bottle mounting structure, and corrective actions, if necessary. The corrective actions include inspections for chafing of the wiring; repair of any damaged wiring in accordance with instructions provided byGulfstream Technical Services; and installation of temporary protective Teflon sheeting, if not already installed, to prevent contact between the wiring harness and oxygen bottle. The alert customer bulletin and amendment reference Gulfstream Aircraft Service Change (ASC) No. 059A, dated August 3, 1998, as an additional source of service information. That ASC describes, among other things, procedures for permanent relocation of the crew oxygen bottle and rework of the lines and tubing associated with the crew and passenger oxygen bottles. Accomplishment of the actions specified in the alert customer bulletin and amendment is intended to adequately address the identified unsafe condition.

Explanation of the Requirements of the Rule
Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design, this AD is being issued to prevent chafing of a wiring harness against the crew oxygen bottle, which could result in electrical shorting and possible fire in the underfloor structure of the airplane. This AD requires accomplishment of the actions specified in the alert customer bulletin and amendment described previously, except as discussed below.

Differences Between This AD and the Alert Customer Bulletin and Amendment
Operators should note that, although the alert customer bulletin and amendment specify that the manufacturer may be contacted for disposition of repair conditions, this AD requires the repair of those conditions to be accomplished in accordance with a method approved by the FAA.

Determination of Rule's Effective Date
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this 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 under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 98-NM-230-AD." The postcard will be date stamped and returned to the commenter.

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.The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, 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: