This section of the FEDERAL REGISTER

contains notices to the public of the proposed

issuance of rules and regulations. The

purpose of these notices is to give interested

persons an opportunity to participate in the

rule making prior to the adoption of the final

rules.

Proposed Rules Federal Register

32369

Vol. 61, No. 122

Monday, June 24, 1996

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95–NM–202–AD]

RIN 2120–AA64

Airworthiness Directives; Gulfstream

Model G–1159 (G–II), G–1159A (G–III),

and G–1159B (G–IIB) Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes the

adoption of a new airworthiness

directive (AD) that is applicable to all

Gulfstream Model G–II, G–III, and G–IIB

series airplanes. This proposal would

require a one-time inspection to detect

corrosion of the material layers of the

lower aft fuselage skin in Fuselage

Station (FS) 580 bulkhead assembly,

and repair, if necessary. The proposal

also would require modification of the

aft fuselage area and various follow-on

actions. This proposal is prompted by

reports of varying levels of corrosion in

the structure at FS 580. The actions

specified by the proposed AD are

intended to prevent the retention of

moisture in the fuselage structure, and

subsequent corrosion in FS 580

bulkhead assembly, which could result

in reduced structural capability of the

skin joint and resultant depressurization

of the airplane.

DATES: Comments must be received by

August 2, 1996.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 95–NM–

202–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, 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:

Steve Flanagan, Aerospace Engineer,

Airframe Branch, ACE–117A, FAA,

Atlanta Aircraft Certification Office,

Small Airplane Directorate, Campus

Building, 1701 Columbia Avenue, Suite

2–160, College Park, Georgia; telephone

(404) 305–7363; 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 95–NM–202–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.

95–NM–202–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The FAA has received reports of

varying levels of pitting and exfoliation

corrosion found in the material layers of

the lower aft fuselage skin of Fuselage

Station (FS) 580 on Gulfstream Model

G–II series airplanes. This corrosion was

detected by operators while performing

visual inspections of the bulkhead area

during routine maintenance checks. FS

580 is the location where the aft

pressure dome ties into the fuselage.

This FS consists of ‘‘multiple stackup

material,’’ such as: a splice strap, failsafe strap, skin, frame, stringers,

longeron, and the pressure dome.

Corrosion in this area is apparently

caused by the accumulation of moisture,

due to condensation in the

unpressurized aft fuselage. This

condition, if not corrected, could result

in reduced structural capability of the

skin joint and resultant depressurization

of the airplane.

Since the aft pressure bulkhead area

on the Model G–II series airplanes is

similar to that on Model G–III and

Model and G–IIB series airplanes, all of

these models may be subject to this

same unsafe condition.

Explanation of Relevant Service

Information

The FAA has reviewed and approved

Gulfstream Customer Bulletin No. 411

(for Model G–II and G–IIB series

airplanes) and No. 125 (for Model G–III

series airplanes), both dated January 28,

1994. These customer bulletins describe

procedures for a one-time visual

inspection or an inspection using

backscattered radiation detection

technique (ComScan) to detect corrosion

in the FS 580 bulkhead assembly.

In addition, the FAA has reviewed

and approved Gulfstream Aircraft

Service Change No. 463 (for Model G–

II and GIIB series airplanes) and No. 267

(for Model G–III series airplanes), both

dated July 21, 1995. These aircraft

service changes describe procedures to:

1. add pressure sealing drain holes in

the aft fuselage area, which will provide

drain paths for condensed water that

has accumulated;

2. remove aluminum-backed foam

from the bays below the floor;

3. modify the fuselage structure;

4. modify the intercoastals;

5. drill drain holes in the area of

Longeron #24L and Stringer #23L, and

Longeron #24R and Stringer #23R; and
32370 Federal Register / Vol. 61, No. 122 / Monday, June 24, 1996 / Proposed Rules

6. treat the structural surfaces with

corrosion inhibitors.

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

require a one-time inspection to detect

corrosion of FS 580, and repair, if

necessary. This inspection could be

accomplished using either detailed

visual inspection techniques or

ComScan techniques.

This proposed AD also would require

that operators submit a report to the

FAA of the findings of this inspection.

The information obtained from these

reports will enable the FAA to

determine how widespread the problem

is in the fleet and if additional action is

warranted.

In addition, the proposed AD would

require:

1. adding pressure sealing drain holes

in the aft fuselage area;

2. removing aluminum-backed foam;

3. modifying the fuselage structure;

4. modify the intercostals;

5. drill drain holes in the area of

Longeron #24L and Stringer #23L, and

Longeron #24R and Stringer #23R; and

6. treat the structural surfaces with

corrosion inhibitors.

Repair of corrosion would be required

to be accomplished in accordance with

a method approved by the FAA. Other

actions would be required to be

accomplished in accordance with the

Gulfstream customer bulletins and

aircraft service changes described

previously.

This is considered to be interim

action until final action is identified, at

which time the FAA may consider

further rulemaking.

Differences Between the Proposed Rule

and Relevant Service Information

Operators should note that, in the

relevant service documents, the

manufacturer recommends that the onetime inspection be accomplished within

18 months for Model G–II and G–IIB

series airplanes, and within 36 months

for Model G–III series airplanes. In

developing an appropriate compliance

time for this proposed rule, the FAA

took into consideration not only those

recommended compliance times, but

the safety implications, normal

maintenance schedules for timely

accomplishment of the inspection, and

the number of days usually required for

the rulemaking process. In

consideration of all of these factors, the

FAA finds that the compliance times for

the one-time inspection as proposed in

this action (6 months for Model G–11

and G–IIB series airplanes, and 12

months for Model G–III series airplanes)

will fall approximately at the same time

of compliance as recommended by the

manufacturer.

Cost Impact

There are approximately 425

Gulfstream Model G–II, G–IIB, and G–III

series airplanes of the affected design in

the worldwide fleet. The FAA estimates

that 345 airplanes of U.S. registry would

be affected by this proposed AD.

To accomplish the one-time

inspection using detailed visual

inspection techniques (which requires

some disassembly) would take

approximately 1,500 work hours per

airplane. To accomplish the one-time

visual inspection using ComScan

techniques would take approximately

16 work hours per airplane. The average

labor rate is $60 per work hour. Based

on these figures, the cost impact of the

proposed one-time inspection on U.S.

operators is estimated to be between

$960 and $90,000 per airplane,

depending upon the type of inspection

performed.

To accomplish the proposed

modification would take approximately

80 work hours per airplane, at an

average labor rate of $60 per work hour.

Based on these figures, the cost impact

of the proposed modification on U.S.

operators is estimated to $1,656,000, or

$4,800 per airplane.

The cost impact figures discussed

above are 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.

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.

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

Gulfstream: Docket 95–NM–202–AD.

Applicability: All Model G–1159 (G–II), G–

1159A (G–III), and G–1159B (G–IIB) series

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 (e) 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 reduced structural

capability of the skin joint and resultant

depressurization of the airplane, as a

result of the problems associated with

corrosion of the structure surfaces aft of

fuselage station (FS) 580, accomplish

the following:

(a) For Model G-II and G-IIB series

airplanes: Within 6 months after the

effective date of this AD, perform a

detailed visual inspection, or perform

an inspection using a backscattered

radiation detection technique

(ComScan), to detect corrosion of the FS
Federal Register / Vol. 61, No. 122 / Monday, June 24, 1996 / Proposed Rules 32371

580 bulkhead, in accordance with

Gulfstream Customer Bulletin No. 411,

dated January 28, 1994. If any corrosion

is found, prior to further flight, repair in

accordance with a method approved by

the Manager, Atlanta Aircraft

Certification Office (ACO), FAA, Small

Airplane Directorate.

(b) For Model G-III series airplanes:

Within 12 months after the effective

date of this AD, perform a one-time

detailed visual inspection, or perform

an inspection using a backscattered

radiation detection technique

(ComScan), to detect corrosion of the FS

580 bulkhead, in accordance with

Gulfstream Customer Bulletin No. 125,

dated January 28, 1994. If any corrosion

is found, prior to further flight, repair in

accordance with a method approved by

the Manager, Atlanta ACO.

(c) For all airplanes: Within 10 days

after accomplishing the inspection

required by paragraph (a) or (b) of this

AD, submit a report of the inspection

results (both positive and negative

findings) to the FAA, Manager, Atlanta

Aircraft Certification Office, Campus

Building, 1701 Columbia Avenue, Suite

2–160, College Park, Georgia 30338–

2748; fax (404) 305–7333. The report

must include the information specified

in paragraphs (d)(1), (d)(2), (d)(3), and

(d)(4) of this AD. 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.

(1) Airplane model, serial number,

date of manufacture, and total number

of hours time-in-service.

(2) Date of inspection, and method of

inspection.

(3) Summary of inspection results,

including extent and location of

corrosion.

(4) List of parts replaced, if

applicable.

(d) For all airplanes: Within 12

months after the effective date of this

AD, add pressure sealing drain holes in

the aft fuselage area; remove all the

aluminum-backed foam insulation from

the skins in the bays between Longerons

#24 left and #24 right from FS 539

through FS 580 inclusive; modify the

fuselage structure; modify the

intercostals; drill drain holes in the area

of Longeron #24L and Stringer #23L,

and Longeron #24R and Stringer #23R;

and treat the structural surfaces with

corrosion inhibitor; in accordance with

either paragraph (c)(1) or (c)(2) of this

AD, as applicable.

(1) For Model G-II and G-IIB series

airplanes: Perform the actions in accordance

with Gulfstream Aircraft Service Change No.

463, dated July 21, 1995.

(2) For Model G-III series airplanes:

Perform the actions in accordance with

Gulfstream Aircraft Service Change No. 267,

dated July 21, 1995.

(e) 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

ACO. 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.

(f) 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 June 17,

1996.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 96–15955 Filed 6–21–96; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 71

[Airspace Docket No. 96–AAL–4]

Proposed Revision of Class D and E

Airspace; Bethel, AK

AGENCY: Federal Aviation

Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking.

SUMMARY: This revision modifies the

Class D and Class E airspace at Bethel,

AK, to accommodate Visual Flight Rules

(VFR) traffic in the Bethel area, landing

and departing from Hanger Lake located

about 2.5 miles northeast of the Bethel

VORTAC. Several Bethel Airport user

groups, during public discussion on the

decommission of the Bethel Approach

Control, requested an exclusion area for

Hanger Lake to accommodate VFR

landings and takeoffs during Instrument

Flight Rules (IFR) weather conditions at

Bethel. The area would be depicted on

aeronautical charts for pilot reference.

The intended effect of this proposal is

to provide adequate exclusion from

Bethel, AK, Class D and Class E airspace

to accommodate Bethel user group

requirements at Hanger Lake.

DATES: Comments must be received on

or before August 12, 1996.

ADDRESSES: Send comments on the

proposal in triplicate to: Manager,

System Management Branch, AAL–530,

Docket No. 96–AAL–4, Federal Aviation

Administration, 222 West 7th Avenue,

Box 14, Anchorage, AK 99513–7587.

The official docket may be examined

in the Office of the Assistant Chief

Counsel for the Alaskan Region at the

same address.

An informal docket may also be

examined during normal business hours

in the Office of the Manager, System

Management Branch, Air Traffic

Division, at the address shown above.

FOR FURTHER INFORMATION CONTACT:

Robert van Haastert, System

Management Branch, AAL–538, Federal

Aviation Administration, 222 West 7th

Avenue, Box 14, Anchorage, AK 99513–

7587; telephone number (907) 271–

5902.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested parties are invited to

participate in this proposed rulemaking

by submitting such written data, views,

or arguments as they may desire.

Comments that provide the factual basis

supporting the views and suggestions

presented are particularly helpful in

developing reasoned regulatory

decisions on the proposal. Comments

are specifically invited on the overall

regulatory, aeronautical, economic,

environmental, and energy-related

aspects of the proposal.

Communications should identify the

airspace docket number and be

submitted in triplicate to the address

listed above. Commenters wishing the

FAA to acknowledge receipt of their

comments on this notice must submit

with those comments a self-addressed,

stamped postcard on which the

following statement is made:

‘‘Comments to Airspace Docket No. 96–

AAL–4.’’ The postcard will be date/time

stamped and returned to the

commenter. All communications

received on or before the specified

closing date for comments will be

considered before taking action on the

proposed rule. The proposal contained

in this notice may be changed in light

of comments received. All comments

submitted will be available for

examination in the System Management

Branch, Air Traffic Division, Federal

Aviation Administration, 222 West 7th

Avenue, Box 14, Anchorage, AK, both

before and after the closing date for

comments. A report summarizing each