[Federal Register Volume 62, Number 44 (Thursday, March 6, 1997)] [Proposed Rules] [Pages 10228-10231] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 97-5461] ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION 14 CFR Part 39 [Docket No. 97-NM-16-AD] RIN 2120-AA64 Airworthiness Directives; Gulfstream Aerospace Corporation Model G-159 (G-I) Airplanes AGENCY: Federal Aviation Administration, DOT. ACTION: Notice of proposed rulemaking (NPRM). ----------------------------------------------------------------------- SUMMARY: This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Gulfstream Model G- 159 (G-I) airplanes, that currently requires modification and repetitive inspections for cracks in the main landing gear (MLG) retract cylinder attachment fittings. This action would require the installation of improved attachment fittings which, when accomplished, [[Page 10229]] would terminate the requirement for the repetitive inspections. This proposal is prompted by the development of a modification that positively addresses the identified unsafe condition. The actions specified by the proposed AD are intended to prevent failure of the MLG retract cylinder attachment fitting due to fatigue cracking. That condition, if not corrected, could result in the inability to retract the MLG. DATES: Comments must be received by April 14, 1997. ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 97-NM-16-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. The service information referenced in the proposed rule may be obtained from Gulfstream Aerospace Corporation, Technical Operations Department, P.O. Box 2206, M/S D-10, Savannah, Georgia 31402-2206. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. FOR FURTHER INFORMATION CONTACT: Christina Marsh, Aerospace Engineer, Airframe and Propulsion Branch, ACE-117A, FAA, Small Airplane Directorate, Atlanta Aircraft Certification Office, Campus Building, 1701 Columbia Avenue, Suite 2-160, College Park, Georgia 30337-2748; telephone (404) 305-7362; fax (404) 305-7348. 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. 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 97-NM-16-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-103, Attention: Rules Docket No. 97-NM-16-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Discussion In 1967, the FAA issued AD 67-31-08, amendment 39-515 (32 FR 16201, November 28, 1967), applicable to certain Gulfstream Model G-159 airplanes, to require repetitive visual and dye penetrant inspections for cracks in the main landing gear (MLG) retract cylinder attachment fittings, part number (P/N) 159WM10032-1 and -2, located on the lower surface of the left-hand and right-hand wings; and replacement of cracked parts. It also requires that the fittings be modified by rounding off their aft end edges. AD 67-31-08 also provided for an optional terminating action, which consisted of replacing the MLG retract cylinder attachment fittings with improved fittings, having Grumman P/N 159WM10276-1 and -2, and balls having Grumman P/N 159WM10277-1. That action was prompted by a report indicating that, during a routine inspection, the MLG retract cylinder attachment fitting on one airplane was found to be cracked through the aft end. Examination of the fitting revealed several notches located along one edge in the area where the failure had occurred. This cracking in the fitting was determined to be due to fatigue that could be directly attributed to these notches. The requirements of that AD are intended to prevent failure of the MLG retract cylinder attachment fitting due to fatigue cracking. This condition, if not corrected, could result in the inability to retract the MLG. Actions Since Issuance of Previous Rule As part of its on-going program to address issues relevant to the continued operational safety of the aging transport fleet, the FAA, along with Gulfstream Aerospace Corporation and several U.S. and non- U.S. operators of the affected airplanes, agreed to undertake the task of identifying and implementing procedures to ensure the continuing structural airworthiness of aging commuter-class airplanes. This group reviewed selected customer bulletins and aircraft service changes, applicable to Gulfstream Model G-159 airplanes, to be recommended for mandatory rulemaking action to ensure the continued operational safety of these airplanes. Explanation of Relevant Service Information The group reviewed and recommended Grumman Gulfstream Service Change No. 184, dated February 1, 1968, and Amendment 1 to that Service Change, dated June 28, 1968, for mandatory rulemaking action. This service information describes procedures for removing MLG retract cylinder attachment fitting assemblies made of aluminum alloy and having P/N 159WM10032-1 and -2, and replacing them with fitting assemblies made of steel and having P/N 159WM10276-1 and -2 and balls having P/N 159WM10277-1. Installation of steel assemblies will preclude the potential for fatigue cracking to occur in the fittings. 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 supersede AD 67-31-08. It would continue to require the repetitive inspections and modification of the MLG retract cylinder attachment fittings, and replacement, if necessary. This new action would require that the attachment fitting assemblies eventually be replaced with assemblies made of steel. Once this replacement is accomplished, the previously required modification and inspections may be terminated. The replacement action would be required to be accomplished in accordance with the service information described previously. FAA's Determination for the Need to Mandate the Replacement The FAA has determined that long term continued operational safety will be better assured by design changes to remove the source of the problem, rather than by repetitive inspections. Long term inspections may not be providing the degree of safety assurance necessary for the transport airplane fleet. This, coupled with a better understanding of the human factors associated with numerous continual inspections, has led [[Page 10230]] the FAA to consider placing less emphasis on inspections and more emphasis on design improvements. The proposed replacement requirement is in consonance with these considerations. Cost Impact There are approximately 146 Gulfstream Model G-159 (G-I) airplanes of the affected design in the worldwide fleet. The FAA estimates that 72 airplanes of U.S. registry would be affected by this proposed AD. The actions that are currently required by AD 67-31-08 take approximately 3 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $12,960, or $180 per airplane, per inspection. The replacement action that is proposed in this AD action would take approximately 45 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts would cost approximately $5,400 per airplane. Based on these figures, the cost impact of the proposed requirements of this AD on U.S. operators is estimated to be $583,200, or $8,100 per airplane. The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the current or proposed 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 proposed herein would 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. 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. 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. Sec. 39.13 [Amended] 2. Section 39.13 is amended by removing amendment 39-515 (32 FR 16201, November 28, 1967), and by adding a new airworthiness directive (AD), to read as follows: Gulfstream Aerospace Corporation (formerly Grumman): Docket 97-NM- 16-AD. Supersedes AD 67-31-08, amendment 39-515. Applicability: Model G-159 (G-I) airplanes; serial numbers (S/N) 1 through 12 inclusive, 14 through 112 inclusive, 114 through 148 inclusive, 322, and 323; on which main landing gear cylinder attach fitting assemblies having part number (P/N) 159WM10276-1 and -2 and balls having P/N 159WM10277-1 are not installed; 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 (d)(1) 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 failure of the main landing gear (MLG) retract cylinder attachment fittings due to fatigue cracking, which could result in the inability to retract the MLG, accomplish the following: (a) Accomplish the actions specified in paragraphs (a)(1) and (a)(2) of this AD, at the times indicated in those paragraphs and in accordance with Grumman Gulfstream Customer Bulletin No. 172, dated September 6, 1963. (1) Beginning November 7, 1967 (the effective date of AD 67-31- 08, amendment 39-515), and prior to each flight, conduct a visual inspection to detect cracks in the MLG retract cylinder attachment fittings on the lower surface of the right-hand and left-hand wings in the vicinity of the aft end of the fitting. (2) Within 25 hours time-in-service after November 7, 1967, accomplish the actions specified in paragraphs (a)(2)(i) and (a)(2)(ii) of this AD: (i) Conduct a dye penetrant inspection, in conjunction with at least a 10X magnifying glass, to detect cracks in the MLG retract cylinder attachment fittings on the lower surface of the right-hand and left-hand wings in the vicinity of the aft end of the fitting. Repeat this inspection thereafter at intervals not to exceed 25 hours time-in-service. And (ii) Modify the aft end edges of the fitting by rounding them off to approximately 1/32'' radius. (b) If any crack is found during an inspection required by paragraph (a) of this AD, prior to further flight, accomplish either paragraph (b)(1) or (b)(2) of this AD: (1) Replace the cracked part with a part of the same part number that has been modified and inspected in accordance with paragraph (a) of this AD, in accordance with Grumman Gulfstream Customer Bulletin No. 172, dated September 6, 1963. Thereafter, continue the inspections required by paragraph (a) of this AD. Or (2) Replace the fitting assembly with an assembly having part number (P/N) 159WM10276-1 or -2, and balls having P/N 159WM10277-1. After accomplishing this replacement, the repetitive inspections of that fitting required by paragraph (a) of this AD may be terminated. (c) Within 400 hours time-in-service after the effective date of this AD, replace the MLG retract cylinder attachment fitting assemblies with assemblies having part numbers (P/N) 159WM10276-1 and -2, and balls having P/N 159WM10277-1. This replacement constitutes terminating action for the inspection requirements of this AD. (d)(1) 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, Small Airplane Directorate. 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. (2) Alternative methods of compliance, approved previously in accordance with AD 67-31-08, amendment 39-515, are approved as alternative methods of compliance with this AD. Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Atlanta ACO. (e) 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. [[Page 10231]] Issued in Renton, Washington, on February 27, 1997. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 97-5461 Filed 3-5-97; 8:45 am] BILLING CODE 4910-13-U