[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]


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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).

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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