[Federal Register Volume 62, Number 44 (Thursday, March 6, 1997)]
[Proposed Rules]
[Pages 10237-10239]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-5467]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 97-NM-17-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).
-----------------------------------------------------------------------
[[Page 10238]]
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 repetitive inspections to
detect cracks and loose rivets in the forward brackets for the main
landing gear (MLG) uplock beam assembly, and replacement of the
brackets, if necessary. This action would require the installation of
redesigned brackets that preclude the potential for cracking and loose
rivets; when accomplished, this installation would constitute
terminating action for the currently required inspections. This
proposal is prompted by the development of an installation that will
positively address the identified unsafe condition. The actions
specified by the proposed AD are intended to prevent failure of the
bracket for the MLG uplock beam assembly due to cracking and loose
rivets; such failure 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-17-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-17-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-17-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
In 1966, the FAA issued AD 66-10-03, amendment 39-222 (31 FR 5660,
April 12, 1966), applicable to certain Gulfstream Model G-159
airplanes, to require repetitive dye penetrant and visual inspections
to detect cracks and loose rivets in the forward brackets of the main
landing gear (MLG) uplock beam assembly, and replacement of the
brackets, if necessary.
That action was prompted by reports of cracks and loose rivets
found in brackets having part number (P/N) 159W10150-51/52. These
conditions were attributed to elongated rivet holes.
The requirements of that AD are intended to prevent such cracking
and loose rivets, which could lead to the failure of the bracket.
Failure of the bracket of the MLG uplock beam assembly 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 (G-I) 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 Part II of Grumman Gulfstream
Service Change No. 179, dated March 15, 1966, for mandatory regulatory
action. (Part I of that service change describes procedures for
repetitive inspections to detect cracks and loose rivets in the forward
brackets of the MLG uplock beam assembly. Those procedures were
mandated by AD 66-10-03.) Part II of the service change describes
procedures for replacing the uplock beam support brackets (angles) with
brackets of an improved design and having P/N 159W10150-71 and -72.
Installation of these improved brackets eliminates the need for the
repetitive inspections.
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 66-10-03. It would continue to require
repetitive dye penetrant and visual inspections to detect cracks and
loose rivets in the forward brackets of the main landing gear (MLG)
uplock beam assembly, and replacement of the brackets, if necessary.
This new action also would require that the currently-installed
brackets be replaced with the improved brackets. Once this replacement
is accomplished, the previously required inspections may be terminated.
The actions would be required to be accomplished in accordance with the
service change 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 the FAA to consider placing less emphasis on inspections and more
[[Page 10239]]
emphasis on design improvements. The proposed replacement requirement
is in consonance with these considerations.
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 would be affected by this proposed AD.
The inspections that are currently required by AD 66-10-03 take
approximately 2 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 $8,640, or $120 per airplane, per inspection.
The terminating replacement that is proposed in this AD action
would take approximately 12 work hours per airplane to accomplish, at
an average labor rate of $60 per work hour. Required parts would cost
approximately $425 per airplane. Based on these figures, the cost
impact of the proposed requirements of this AD on U.S. operators is
estimated to be $82,440, or $1,145 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 39-222 (31 FR
5660, April 12, 1966), and by adding a new airworthiness directive
(AD), to read as follows:
Gulfstream Aerospace Corporation (formerly Grumman): Docket 97-NM-
17-AD. Supersedes AD 66-10-03, Amendment 39-222.
Applicability: Model G-159 (G-I) airplanes; serial numbers (S/N)
1 through 12 inclusive, 14 through 83 inclusive, and 114; on which
main landing gear uplock beam support brackets (angles) having part
numbers (P/N) 159W10150-71 and -72 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 brackets for the main landing gear
(MLG) uplock beam assembly due to cracking and loose rivets, which
could result in the inability to retract the MLG, accomplish the
following:
(a) Within 50 hours time-in-service after April 12, 1966 (the
effective date of AD 66-10-03, amendment 39-222), and thereafter at
intervals not to exceed 100 hours time-in-service, accomplish the
actions specified in paragraphs (a)(1) and (a)(2) of this AD in
accordance with Grumman Gulfstream Service Change No. 179, dated
March 15, 1966:
(1) Conduct a dye penetrant inspection, in conjunction with at
least a 10X magnifying glass, to detect cracks in the MLG uplock
beam forward brackets, P/N's 159W10150-51 and -52; and
(2) Conduct a visual inspection of the attachments of each
bracket to the firewall bulkhead and to the main gear uplock beam
for loose rivets caused by elongated rivet holes.
(b) If any crack or loose rivet is found during any inspection
required by paragraph (a) of this AD, prior to further flight,
accomplish either paragraph (b)(1) or (b)(2) of this AD, in
accordance with Grumman Gulfstream Service Change No. 179, dated
March 15, 1966:
Note 2: Grumman Gulfstream Service Change No. 179A, dated March
20, 1966, contains additional procedural information relevant to the
inspection and replacement requirements of this AD.
(1) Replace the bracket with a new or serviceable bracket having
P/N 159W10150-51 or -52, as applicable. After this replacement,
continue to inspect in accordance with paragraph (a) of this AD. Or
(2) Replace the bracket with a bracket having P/N 159W10150-71
or -72, as applicable. This replacement constitutes terminating
action for the inspection required by paragraph (a) of this AD for
the replaced bracket.
(c) Within 1,000 hours time-in-service after the effective date
of this AD, replace the brackets for the main landing gear (MLG)
uplock beam assembly with brackets having P/N 159W10150-71 and -72,
in accordance with Part II of Grumman Gulfstream Service Change No.
179, dated March 15, 1966. Such replacement constitutes terminating
action for the inspections required by 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 66-10-03, amendment 39-222, are approved as
alternative methods of compliance with this AD.
Note 3: 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.
Issued in Renton, Washington, on February 27, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 97-5467 Filed 3-5-97; 8:45 am]
BILLING CODE 4910-13-U
