[Federal Register Volume 71, Number 133 (Wednesday, July 12, 2006)]
[Proposed Rules]
[Pages 39242-39244]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-10911]



[[Page 39242]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-143-AD]
RIN 2120-AA64


Airworthiness Directives; Gulfstream Aerospace Model G-159 
Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Supplemental notice of proposed rulemaking; reopening of 
comment period.

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SUMMARY: This document revises an earlier supplemental notice of 
proposed rulemaking (NPRM), applicable to all Gulfstream Aerospace 
Corporation Model G-159 airplanes, that would have required repetitive 
non-destructive testing inspections to detect corrosion of the skin of 
certain structural assemblies, and corrective action if necessary. The 
first supplemental NPRM also would have required x-ray and ultrasonic 
inspections to detect corrosion and cracking of the splicing of certain 
structural assemblies, and repair if necessary. This new action revises 
the proposed rule by limiting the time certain repetitive inspections 
may be repeated before corrective action must be taken. The actions 
specified by this new proposed supplemental AD are intended to detect 
and correct corrosion and cracking of the lower wing plank splices and 
spot-welded skins of certain structural assemblies, which could result 
in reduced controllability of the airplane. This action is intended to 
address the identified unsafe condition.

DATES: Comments must be received by August 7, 2006.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 96-NM-143-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 96-NM-143-AD'' in the subject line and need not be 
submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 or 2000 or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Gulfstream Aerospace Corporation, Technical Publications 
Dept., P.O. Box 2206, Savannah, Georgia 31402-2206. This information 
may be examined at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington; or at the FAA, Atlanta Aircraft 
Certification Office, One Crown Center, 1895 Phoenix Boulevard, suite 
450, Atlanta, Georgia.

FOR FURTHER INFORMATION CONTACT: Michael Cann, Aerospace Engineer, 
Airframe Branch, ACE-117A, FAA, Atlanta Aircraft Certification Office, 
One Crown Center, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia 
30349; telephone (770) 703-6038; fax (770) 703-6097.

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 action may be changed in 
light of the comments received.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    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 action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 96-NM-143-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this second supplemental NPRM by 
submitting a request to the FAA, Transport Airplane Directorate, ANM-
114, Attention: Rules Docket No. 96-NM-143-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.

Discussion

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to add an airworthiness directive (AD), applicable to all 
Gulfstream Aerospace Corporation Model G-159 airplanes, was published 
as a supplemental notice of proposed rulemaking (NPRM) in the Federal 
Register on March 21, 2006 (71 FR 14123). The first supplemental NPRM 
would have required repetitive non-destructive testing inspections to 
detect corrosion of the skin of certain structural assemblies, and 
corrective action if necessary. The first supplemental NPRM also would 
have required x-ray and ultrasonic inspections to detect corrosion and 
cracking of the splicing of certain structural assemblies, and repair 
if necessary. The first supplemental NPRM was prompted by reports 
indicating corrosion had been detected in a larger area than previously 
reported. That condition, if not detected and corrected, could result 
in cracking of the lower wing plank splices and spot-welded skins of 
certain structural assemblies, which could result in reduced 
controllability of the airplane. That action was intended to address 
the identified unsafe condition.

Comments

    Due consideration has been given to the comments received in 
response to the first supplemental NPRM.

Request To Clarify Paragraph (a)(3) of the Supplemental NPRM

    The manufacturer, Gulfstream, requests that the inspection 
specified in paragraph (a)(3) of the NPRM be revised to specify that 
the airplane may remain in service for up to 18 months with a proviso 
that repeat x-ray inspections are accomplished at 9-month intervals 
until rework or replacement is accomplished.
    We agree that further clarification is necessary for paragraph 
(a)(3) of this second supplemental NPRM and have revised paragraph 
(a)(3) accordingly.

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Request To Clarify the Areas of Inspection

    The same commenter, Gulfstream, would like us to clarify the 
``Summary'' section of the first supplemental NPRM. The commenter 
states that Customer Bulletin (CB) 337B, dated August 17, 2005 expands 
only the wing lower plank inspection from WS 40 to WS 310. Gulfstream 
points out that all other areas identified within CB 337, Revision B, 
were established as part of the original CB inspection criteria.
    We acknowledge the commenter's point. However, the intent of the 
first supplemental NPRM was to specify that the wing lower plank 
inspection was being added to the proposed requirements of the original 
NPRM. The proposed requirements are in accordance with Gulfstream GI CB 
337B, dated August 17, 2005. No change is necessary to this 
supplemental NPRM as a result of that comment.

Request To Clarify Reference to ``Exfoliation'' Corrosion

    Gulfstream also requests that we clarify the reference to 
``exfoliation'' in the ``Relevant Customer Bulletin'' section of the 
preamble of the supplemental NPRM by changing the reference to ``inter-
granular/exfoliation'' corrosion. Gulfstream states that, in order to 
convey the nature of this type of corrosion, it is important to 
understand that inter-granular starts first with the visible result, 
exfoliation, typically following significant structural damage. 
Gulfstream further notes that inter-granular corrosion often cannot be 
visibly seen as it goes down from the surface, transitions sideways 
following the boundary layer for a distance, and cannot be seen without 
non-destructive testing (NDT) inspection.
    We acknowledge the commenter's clarification regarding the 
reference to exfoliation in the supplemental NPRM. However, since the 
description of the ``Relevant Customer Bulletin'' does not reappear in 
this supplemental NPRM, it is unnecessary to revise this supplemental 
NPRM.

Request To Clarify ``Difference Between the CB and the Proposed AD''

    Gulfstream also notes that Gulfstream GI CB 337 refers to the 
Airplane Maintenance Manual (AMM), Chapter 05, which specifies 
corrective actions and follow-up inspection intervals.
    We infer that Gulfstream would like us to clarify that, while the 
CB does not explicitly specify repetitive inspections, the CB does 
refer to the AMM, which contains certain corrective actions and 
repetitive inspection intervals. We acknowledge that Gulfstream CB 
337B, dated August 17, 2005, refers to the AMM, and that the AMM 
specifies certain repetitive inspection intervals. Since the 
``Differences Between the CB and the Proposed AD'' section does not 
reappear in this supplemental AD, no change to this supplemental NPRM 
is necessary.

Request To Change Reporting Address

    Gulfstream requests that we update the address where the reporting 
requirements are to be sent.
    We agree to change the address for the reporting requirements and 
have revised this supplemental NPRM accordingly.

Editorial Change

    We have also revised paragraph (f) of this supplemental NPRM to 
remove the phrase, ``as defined by paragraphs (f)(1) and (f)(2) of this 
AD:''. That phrase was intended to define new lower wing planks based 
on when the new lower wing planks were installed. We removed that 
phrase, since the compliance time (within 144 months after replacement 
of the lower wing planks with new lower wing planks, or within 9 months 
after the effective date of this AD, whichever occurs later) is the 
same for all new lower wing planks.

Conclusion

    Since these changes expand the scope of the first supplemental 
NPRM, the FAA has determined that it is necessary to reopen the comment 
period to provide additional opportunity for public comment.

Changes to 14 CFR Part 39/Effect on the Proposed AD

    On July 10, 2002, the FAA issued a new version of 14 CFR part 39 
(67 FR 47997, July 22, 2002), which governs the FAA's airworthiness 
directives system. The regulation now includes material that relates to 
altered products, special flight permits, and alternative methods of 
compliance (AMOCs). These changes are reflected in this supplemental 
NPRM.

Explanation of Change to Costs of Compliance

    After the first supplemental NPRM was issued, we reviewed the 
figures we have used over the past several years to calculate AD costs 
to operators. To account for various inflationary costs in the airline 
industry, we find it necessary to increase the labor rate used in these 
calculations from $65 per work hour to $80 per work hour. The cost 
impact information, below, reflects this increase in the specified 
hourly labor rate.

Cost Impact

    There are approximately 52 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 25 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take approximately 
between 300 and 450 work hours per airplane, depending upon how many 
spot-welded skins have been replaced with bonded skin panels, to 
accomplish the proposed actions, and that the average labor rate is $80 
per work hour. Based on these figures, the cost impact of the proposed 
AD on U.S. operators is estimated to be between $600,000 and $900,000, 
or between $24,000 and $36,000 per airplane per inspection cycle.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed requirements of 
this AD action, and that no operator would accomplish those actions in 
the future if this AD were not adopted. The cost impact figures 
discussed in AD rulemaking actions represent only the time necessary to 
perform the specific actions actually required by the AD. These figures 
typically do not include incidental costs, such as the time required to 
gain access and close up, planning time, or time necessitated by other 
administrative actions.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Impact

    The regulations proposed herein would not have a substantial direct 
effect 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,

[[Page 39244]]

it is determined that this proposal would not have federalism 
implications under Executive Order 13132.
    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 adding the following new 
airworthiness directive:

Gulfstream Aerospace Corporation: Docket 96-NM-143-AD.

    Applicability: All Model G-159 airplanes, certificated in any 
category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To detect and correct corrosion and cracking of the spot-welded 
skins of the lower wing plank splices and certain structural 
assemblies, which could result in reduced controllability of the 
airplane, accomplish the following:

    Note 1: A note in the Accomplishment Instructions of the 
Gulfstream customer bulletin instructs operators to contact 
Gulfstream if any difficulty is encountered in accomplishing the 
customer bulletin. However, any deviation from the instructions 
provided in the customer bulletin must be approved as an alternative 
method of compliance (AMOC) under paragraph (h) of this AD.

Non-Destructive Testing Inspections of the Fuselage, Empennage, and 
Flight Controls

    (a) Within 9 months after the effective date of this AD, perform 
a non-destructive test (NDT) to detect corrosion of the skins of the 
elevators, ailerons, rudder and rudder trim tab, flaps, aft lower 
fuselage, and vertical and horizontal stabilizers; in accordance 
with the Accomplishment Instructions of Gulfstream GI Customer 
Bulletin (CB) 337B, including Appendix A, dated August 17, 2005. The 
corrosion criteria must be determined by the Manager, Atlanta 
Aircraft Certification Office (ACO), FAA. Gulfstream Tool ST905-377 
is also an acceptable method of determining the corrosion criteria.
    (1) If no corrosion or cracking is detected, repeat the 
inspection thereafter at intervals not to exceed 18 months.
    (2) If any corrosion is detected that meets the criteria of 
``light'' or ``mild'' corrosion, repeat the NDT inspections of that 
component thereafter at intervals not to exceed 12 months.
    (3) If any corrosion is detected that meets the criteria of 
``moderate'' corrosion: Within 9 months after the initial 
inspection, repeat the NDT inspection of that component, and within 
18 months since the initial inspection, repair or replace the 
component with a serviceable component in accordance with the CB.
    (4) If any corrosion is detected that meets the criteria of 
``severe'' corrosion, before further flight, replace the component 
with a serviceable component in accordance with the CB.

Existing Repairs

    (b) If any existing repairs are found during the inspections 
required by paragraph (a) of this AD, before further flight, ensure 
that the repairs are in accordance with a method approved by the 
Manager, Atlanta ACO.

Inspections of the Lower Wing Plank

    (c) Except as provided in paragraph (f) of this AD: Within 9 
months after the effective date of this AD, perform NDT inspections 
to detect corrosion and cracking of the lower wing plank splices, in 
accordance with the Accomplishment Instructions of Gulfstream GI CB 
337B, including Appendix A, dated August 17, 2005.
    (1) If no corrosion or cracking is detected, repeat the NDT 
inspection at intervals not to exceed 18 months.
    (2) If any corrosion or cracking is detected, before further 
flight, perform all applicable investigative actions and corrective 
actions in accordance with the customer bulletin.

Repair Removal Threshold

    (d) For repairs specified in Appendix A of Gulfstream GI CB 
337B, dated August 17, 2005: Within 144 months after the date of the 
repair installation, remove the repaired component and replace it 
with a new or serviceable component, in accordance with Gulfstream 
GI CB 337B, including Appendix A, dated August 17, 2005.

Prior Blending in the Riser Areas

    (e) If, during the performance of the inspections required by 
paragraph (c) or (f) of this AD, the inspection reveals that prior 
blending has been performed on the riser areas: Before further 
flight, perform an eddy current or fluorescent penetrant inspection, 
as applicable, to evaluate the blending, and accomplish appropriate 
corrective actions, in accordance with the Accomplishment 
Instructions of Gulfstream GI CB 337B, including Appendix A, dated 
August 17, 2005. If any blend-out is outside the limits specified in 
the CB, before further flight, repair in a manner approved by the 
Manager, Atlanta ACO.

For Airplanes With New Lower Wing Planks

    (f) For airplanes with new lower wing planks: Within 144 months 
after replacement of the lower wing planks with new lower wing 
planks, or within 9 months after the effective date of this AD, 
whichever occurs later, perform all of the actions, including any 
other related investigative actions and corrective actions, 
specified in paragraph (c) of this AD.

Reporting Requirement

    (g) Within 30 days of performing the inspections required by 
this AD: Submit a report of inspection findings (both positive and 
negative) to Gulfstream Aerospace Corporation; Attention: Technical 
Operations--Structures Group, Dept. 893, Mail Station D-25, 500 
Gulfstream Road, Savannah, Georgia 31408. Information collection 
requirements contained in this regulation have been approved by the 
Office of Management and Budget (OMB) under the provisions of the 
Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have 
been assigned OMB Control Number 2120-0056.

Alternative Methods of Compliance

    (h)(1) The Manager, Atlanta ACO, has the authority to approve 
AMOCs for this AD, if requested in accordance with the procedures 
found in 14 CFR 39.19.
    (2) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.

    Issued in Renton, Washington, on June 30, 2006.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-10911 Filed 7-11-06; 8:45 am]
BILLING CODE 4910-13-P