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

Proposed Rules

Federal Register

________________________________________________________________________

========================================================================

Proposed Rules

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-18-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 all Gulfstream Model G-159

(G-I) airplanes, that currently requires repetitive inspections to

detect corrosion in the wing planks under the bottom wing center

fairings, and repair, if necessary. This action would require the

installation of a protective paint system which, when accomplished,

will allow the inspections to be conducted at longer intervals. This

action was prompted by the development of a modification that will

improve the corrosion resistance of the subject area. The actions

specified by the proposed AD are intended to detect and prevent

corrosion in the lower skins of the wing center section. If corrosion

in this area remains unchecked, it could reduce the integrity of the

wing-to-fuselage fitting, and consequently could lead to separation of

the wing from the airplane.

DATES: Comments must be received by April 14, 1997.

istance of the subject area. The actions

specified by the proposed AD are intended to detect and prevent

corrosion in the lower skins of the wing center section. If corrosion

in this area remains unchecked, it could reduce the integrity of the

wing-to-fuselage fitting, and consequently could lead to separation of

the wing from the airplane.

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-18-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

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-18-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-18-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion

ich the following statement is made: ``Comments

to Docket Number 97-NM-18-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-18-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion

In 1967, the FAA issued AD 67-04-01, amendment 39-1234 (36 FR

12688, July 3, 1971), applicable to all Gulfstream Model G-159 (G-I)

airplanes. That AD requires a visual inspection to detect corrosion of

the wing planks under the bottom wing center fairing assemblies (having

part numbers 159W10400-121 and 159W10401-121), and repair if necessary.

After the initial inspection is accomplished, and after any repair is

made, the inspection is required to be repeated at intervals of 26

weeks.

That action was prompted by reports indicating that corrosion was

found in the lower skins of the wing center section of several of these

airplanes. The requirements of that AD are intended to detect and

correct corrosion in this area. If such corrosion remains unchecked, it

could reduce the integrity of the wing-to-fuselage fitting, and

consequently could lead to separation of the wing from the airplane.

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

recently reviewed selected service bulletins, 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

task

of identifying and implementing procedures to ensure the continuing

structural airworthiness of aging commuter-class airplanes. This group

recently reviewed selected service bulletins, 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 I Aircraft

Service Change No. 190, dated June 28, 1971, for mandatory regulatory

action. That service change describes procedures for repetitive

inspections to detect corrosion of the center section lower wing

planks, and repair, if necessary. It also describes the

installation of a protective paint system to the fairing assemblies and

bottom wing cover. This protective system is intended to improve the

corrosion resistance of this area. Once it is installed, the repetitive

inspections may be conducted at longer intervals.

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 67-04-01. It would continue to require

the repetitive visual inspections, specified in AD 67-04-01, to detect

corrosion of the wing planks under the bottom wing center fairing

assemblies, and repair, if necessary.

For airplanes on which a protective paint system had not been

installed previously, this new action would require that the inspection

continue to be repeated at intervals of 6 months (26 weeks), until a

protective paint system is installed within 12 months. Once the paint

system is installed, the repetitive inspections would be required to

continue, but the repetitive interval would be extended to 18 months.

For airplanes on which a protective paint system was installed

previously, this new action would extend the currently-required

repetitive inspection interval of 12 months to 18 months

a

protective paint system is installed within 12 months. Once the paint

system is installed, the repetitive inspections would be required to

continue, but the repetitive interval would be extended to 18 months.

For airplanes on which a protective paint system was installed

previously, this new action would extend the currently-required

repetitive inspection interval of 12 months to 18 months.

These actions would be required to be accomplished in accordance

with the aircraft service change described previously.

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 67-04-01, and

those that would be required by this proposed action, take

approximately 40 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 proposed inspection actions on U.S. operators is

estimated to be $172,800, or $2,400 per airplane, per inspection.

The installation of the protective paint system that is proposed in

this AD action would take approximately 30 work hours per airplane to

accomplish, at an average labor rate of $60 per work hour. Required

materials would cost approximately $100 per airplane. Based on these

figures, the cost impact of the proposed requirements of this AD on

U.S. operators is estimated to be $136,800, or $1,900 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

pact of the proposed requirements of this AD on

U.S. operators is estimated to be $136,800, or $1,900 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]

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 39-1234 (36 FR

12688, July 3, 1971), and by adding a new airworthiness directive (AD),

to read as follows:

Gulfstream Aerospace Corporation: Docket 97-NM-18-AD. Supersedes AD

67-04-01, Amendment 39-1234.

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 (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 detect and prevent corrosion in the lower skins of the wing

center section, which could reduce the integrity of the wing-to-

fuselage fitting and consequently could lead to separation of the

wing from the airplane, accomplish the following:

en

eliminated, the request should include specific proposed actions to

address it.

Compliance: Required as indicated, unless accomplished

previously.

To detect and prevent corrosion in the lower skins of the wing

center section, which could reduce the integrity of the wing-to-

fuselage fitting and consequently could lead to separation of the

wing from the airplane, accomplish the following:

(a) For all airplanes: Within 4 weeks after July 3, 1971 (the

effective date of AD 67-04-01, amendment 39-1234), remove the bottom

wing center fairings having part numbers (P/N) 159W10400-121 and

159W10401-121, or use an FAA-approved equivalent method, to perform

a visual inspection to detect corrosion of the wing planks under

these fairings.

Note 2: Paragraph (a) of this AD merely restates the actions

previously required by AD 67-04-01, amendment 39-1234. As allowed by

the phrase, ``unless accomplished previously,'' if those

requirements of AD 67-04-01 have already been accomplished, this AD

does not require that those actions be repeated.

Note 3: Care must be exercised when removing the fairings, since

the attaching rivets go into the pressure vessel. Use caution not to

enlarge rivet holes when removing rivets. When reinstalling the

fairings, an adequate type fastener and sealant must be used.

Note 4: Grumman Service Newsletter, Volume 166, dated August-

September 1966, pertains to this subject.

(b) For airplanes on which a protective paint system has not

been installed in accordance with Grumman Gulfstream I Aircraft

Service Change No. 190, dated June 28, 1971: Accomplish paragraphs

(b)(1) and (b)(2) of this AD. As of the effective date of this AD,

the inspections required by this paragraph shall be accomplished in

accordance with Grumman Gulfstream I Aircraft Service Change No.

190, dated June 28, 1971.

Note 5: The repeated inspection referred to in this paragraph is

the same inspection previously required by AD 67-04-01. Paragraph

une 28, 1971: Accomplish paragraphs

(b)(1) and (b)(2) of this AD. As of the effective date of this AD,

the inspections required by this paragraph shall be accomplished in

accordance with Grumman Gulfstream I Aircraft Service Change No.

190, dated June 28, 1971.

Note 5: The repeated inspection referred to in this paragraph is

the same inspection previously required by AD 67-04-01. Paragraph

(b)(1) of this AD merely restates

the requirement of AD 67-04-01 to repeat the inspection at intervals

of 6 months. Paragraph (b)(2) permits the reinspection interval to

be extended to 18 months once the specified protective paint system

is installed.

(1) As a result of the inspection required by paragraph (a) of

this AD:

(i) If no corrosion is detected, repeat the inspection

thereafter at intervals not to exceed 6 months (26 weeks) until the

actions specified in paragraph (b)(2) of this AD are accomplished.

(ii) If any corrosion is detected, prior to further flight,

either repair the corroded part with an FAA-approved repair; or

replace the corroded part with a new or serviceable part of the same

part number; or replace the corroded part with a part approved by

the FAA. Thereafter, continue to perform the inspection at intervals

not to exceed 6 months (26 weeks) until paragraph (b)(2) of this AD

is accomplished.

(2) Within 12 months after the effective date of this AD,

install the protective paint system in accordance with Grumman

Gulfstream I Aircraft Service Change No. 190, dated June 28, 1971.

After installation, continue to perform the inspection required by

this paragraph at intervals not to exceed 18 months.

any corrosion is detected, prior to further flight,

either repair the corroded part with an FAA-approved repair; or

replace the corroded part with a new or serviceable part of the same

part number; or replace the corroded part with a part approved by

the FAA. Thereafter, continue to perform the inspection at intervals

not to exceed 12 months until paragraph (c)(2) of this AD is

accomplished.

(2) Within 18 months since the last inspection accomplished in

accordance with paragraph (c)(1) of this AD (i.e., the last

inspection accomplished in accordance with AD 67-04-01), repeat the

inspection specified in paragraph (c)(1) of this AD.

(i) If no corrosion is detected, repeat the inspection

thereafter at intervals not to exceed 18 months.

(ii) If any corrosion is detected, prior to further flight,

repair in accordance with the service change. After repair, continue

to perform the inspection at intervals not to exceed 18 months.

(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 67-04-01, amendment 39-1234, are approved as

alternative methods of compliance with this AD.

Note 7: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Atlanta ACO.

who may add comments and then send it to the

Manager, Atlanta ACO.

(2) Alternative methods of compliance, approved previously in

accordance with AD 67-04-01, amendment 39-1234, are approved as

alternative methods of compliance with this AD.

Note 7: 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. 97-5463 Filed 3-5-97; 8:45 am]

BILLING CODE 4910-13-U