[Federal Register Volume 62, Number 133 (Friday, July 11, 1997)]
[Rules and Regulations]
[Pages 37127-37128]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-17560]



[[Page 37127]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-19-AD; Amendment 39-10069; AD 97-14-13]
RIN 2120-AA64


Airworthiness Directives; Gulfstream Aerospace Corporation Model 
G-159 (G-I) Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to certain Gulfstream Model G-159 (G-I) airplanes, 
that currently requires repetitive inspections to detect chafe wear on 
the upper diagonal engine mount tube, and replacement or repair, if 
necessary. This amendment requires the installation of chafe guards at 
the engine mounts, which terminates the currently required inspections. 
It also requires that the chafe guards then be repetitively inspected 
for chafe wear. This amendment is prompted by the development of a 
modification that will provide better protection of the subject area 
against future chafe wear. The actions specified by this AD are 
intended to prevent excessive chafe wear in the area of the upper 
diagonal engine mount tubes and trusses; if not detected and corrected, 
such wear could result in failure of the engine mount assembly and 
possible separation of the engine from the airplane.

DATES: Effective August 15, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of August 15, 1997.

ADDRESSES: The service information referenced in this AD 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 Federal Aviation Administration 
(FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, 
SW., Renton, Washington; or at the FAA, Atlanta Aircraft Certification 
Office, Small Airplane Directorate, Campus Building, 1701 Columbia 
Avenue, Suite 2-160, College Park, Georgia; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, Washington, 
DC.

FOR FURTHER INFORMATION CONTACT: Christina Marsh, Aerospace Engineer, 
Airframe and Propulsion Branch, ACE-117A, FAA, Atlanta Aircraft 
Certification Office, Small Airplane Directorate, Campus Building, 1701 
Columbia Avenue, Suite 2-160, College Park, Georgia 30337-2748; 
telephone (404) 305-7362; fax (404) 305-7348.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 67-17-05, 
amendment 39-511 (32 FR 7248, May 16, 1967), which is applicable to 
certain Gulfstream Model G-159 (G-I) airplanes, was published in the 
Federal Register on March 6, 1997 (62 FR 10226). The action proposed to 
superseded AD 67-17-05 to continue to require repetitive visual 
inspections to detect chafe wear of the engine mount tube, and repair 
or replacement of the tube(s), if necessary. These inspections would be 
required to continue until (1) a one-time inspection is performed to 
detect chafe wear of the upper diagonal truss, and (2) chafe guards are 
installed. (Once chafe guards are installed, the previously required 
visual inspections of the engine mount tubes would be terminated.) The 
action also proposed to require that, after the chafe guards are 
installed, an inspection of the chafe guards be conducted at intervals 
of 2,500 hours time-in-service.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were submitted in response 
to the proposal or the FAA's determination of the cost to the public.

Conclusion

    The FAA has determined that air safety and the public interest 
require the adoption of the rule as proposed.

Cost Impact

    There are approximately 146 Gulfstream Model G-159 airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 72 
airplanes of U.S. registry will be affected by this AD.
    The actions that are currently required by AD 67-17-05 take 
approximately 4 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 $17,280, or $240 per airplane, per inspection.
    The installation of the chafe guards that is required by this AD 
action will take approximately 40 work hours per airplane to 
accomplish, at an average labor rate of $60 per work hour. Required 
parts will cost approximately $152 per airplane. Based on these 
figures, the cost impact of the requirements of this AD on U.S. 
operators is estimated to be $183,744, or $2,552 per airplane.
    The inspections of the chafe guards that are required by this AD 
action will take approximately 4 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 $17,280, or $240 per airplane, per inspection.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the 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 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.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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:


[[Page 37128]]


    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-511 (32 FR 
7248, May 16, 1967), and by adding a new airworthiness directive (AD), 
amendment 39-10069, to read as follows:

97-14-13 Gulfstream Aerospace Corporation (formerly Grumman): 
Amendment 39-10069. Docket 97-NM-19-AD. Supersedes AD 67-17-05, 
Amendment 39-511.
    Applicability: All Model G-159 (G-I) airplanes, certificated in 
any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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 excessive chafe wear of the engine mount tube and 
upper diagonal truss, which could lead to failure of the engine 
mount assembly and possible separation of the engine from the 
airplane, accomplish the following:
    (a) For airplanes on which chafe guards, part number (P/N) 
159WP10017-11, have not been installed on each upper diagonal truss 
prior to the effective date of this AD: Accomplish paragraphs 
(a)(1), (a)(2), and (a)(3) of this AD:
    (1) Restatement of Requirements of AD 67-17-05: Within 100 hours 
time-in-service after May 16, 1967 (the effective date of AD 67-17-
05, amendment 39-511), visually inspect to detect chafe wear of the 
lower half of the upper diagonal engine amount tubes having P/N 
159W10172-11 (left engine) and P/N 159W10172-13 (right engine).
    (i) If no chafe wear is detected: Repeat this inspection 
thereafter at intervals not to exceed 200 hours time-in-service 
until the requirements of paragraph (a)(2) are accomplished.
    (ii) If any tube is found to have wear depth greater than 0.030 
inch (as measured from the outer edge of the tube): Prior to further 
flight, replace the tube with a tube of the same part number or with 
an FAA-approved equivalent part. After replacement, repeat the 
inspection required by this paragraph at intervals not to exceed 200 
hours time-in-service until the requirements of paragraph (a)(2) are 
accomplished.
    (iii) If any tube is found to have wear depth of 0.030 inch deep 
or less, as measured from the outer edge of the tube: Prior to 
further flight, either repair the tube in accordance with an FAA-
approved repair, or replace the tube with a part of the same part 
number or with an FAA-approved equivalent part. After repair or 
replacement, repeat the inspection required by this paragraph at 
intervals not to exceed 200 hours time-in-service until the 
requirements of paragraph (a)(2) are accomplished.
    (2) One-Time Inspection of Upper Diagonal Truss and Installation 
of Chafe Guards. Within 600 hours time-in-service after the 
effective date of this AD, perform a one-time visual inspection to 
detect chafe wear of the left-hand and right-hand upper diagonal 
truss, P/N's 159W10172-5 (left-hand nacelle) and P/N 159W10172-7 
(right-hand nacelle), in accordance with Grumman Gulfstream Service 
Change No. 180, dated October 17, 1966. Once this inspection is 
completed, the repetitive inspections required by paragraph (a)(1) 
of this AD may be terminated.
    (i) If there is no evidence of chafe wear on the truss; or if 
there is evidence of chafe wear and the depth of wear is .030 inch 
or less (measured from the surface of the tube): Prior to further 
flight, install a chafe guard, P/N 159WP10017-11, on the truss.
    (ii) If there is any evidence of chafe wear and the depth of 
wear exceeds .030 inch measured (from the surface of the tube): 
Prior to further flight, install a new upper diagonal truss and 
install a chafe guard, P/N 159WP10017-11, on the truss.
    (3) Continuing Inspections of Chafe Guards. Within 2,500 hours 
time-in-service after installation of the chafe guards required by 
paragraph (a)(2) of this AD, perform an inspection of the 
undersurface of each chafe guard for evidence of chafe wear, in 
accordance with Grumman Gulfstream Service Change No. 180, dated 
October 17, 1966.
    (i) If no chafe wear is detected: Repeat the inspection at 
intervals not to exceed 2,500 hours time-in-service.
    (ii) If any chafe wear is detected: Prior to further flight, 
replace the chafe guard with a new or serviceable part. After 
replacement, repeat the inspection for chafe wear of the chafe guard 
thereafter at intervals not to exceed 2,500 hours time-in-service.
    (b) For airplanes on which chafe guards, P/N 159WP10017-11, have 
been installed on each upper diagonal truss prior to the effective 
date of this AD: Within 2,500 hours time-in-service after the last 
inspection of the chafe guard required by paragraph (c) of AD 67-17-
05, repeat that inspection to detect chafe wear of the chafe guards 
in accordance with Grumman Gulfstream Service Change No. 180, dated 
October 17, 1966.
    (1) If no chafe wear is detected: Repeat the inspection 
thereafter at intervals not to exceed 2,500 hours time-in-service.
    (2) If any chafe wear is detected: Prior to further flight, 
replace the chafe guard with a new or serviceable part. After 
replacement, repeat the inspection thereafter at intervals not to 
exceed 2,500 hour time-in-service.
    (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 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.

    Note 2: 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 
Secs. 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) The actions shall be done in accordance with Grumman 
Gulfstream Service Change No. 180, dated October 17, 1966. 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, 
Technical Operations Department, P.O. Box 2206, M/S D-10, Savannah, 
Georgia 31402-2206. Copies may be inspected at the FAA, Transport 
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or 
at the FAA, Atlanta Aircraft Certification Office, Small Airplane 
Directorate, Campus Building, 1701 Columbia Avenue, Suite 2-160, 
College Park, Georgia; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC.
    (f) This amendment becomes effective on August 15, 1997.

    Issued in Renton, Washington, on June 30, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-17560 Filed 7-10-97; 8:45 am]
BILLING CODE 4910-13-M