Federal Register / Vol. 62, No. 44 / Thursday, March 6, 1997 / Proposed Rules 10231

Issued in Renton, Washington, on February

27, 1997.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–5461 Filed 3–5–97; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 97–NM–15–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 certain

Gulfstream Model G–159 (G–I)

airplanes, that currently requires

repetitive inspections to detect cracking

in the mounting lugs of the elevator trim

tab actuators, and replacement, if

necessary. This action would require the

installation of improved elevator trim

tab actuators that are not susceptible to

the subject cracking. This proposal is

prompted by the development of a

modification that positively addresses

the identified unsafe condition. The

actions specified by the proposed AD

are intended to prevent failure of the

mounting lugs on the elevator trim tab

actuator due to cracking; such failure

could result in severe vibration during

flight and/or reduction or loss of

elevator trim tab capability, which

could lead to reduced controllability of

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–

15–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–15–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–15–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

In 1972, the FAA issued AD 72–24–

04, amendment 39–1559 (37 FR 24419,

November 17, 1972), applicable to

certain Gulfstream Model G–159’’

airplanes (formerly designated as

‘‘Grumman Gulfstream G–159’’

airplanes), to require: 1. repetitive dye penetrant inspections

to detect cracking in the mounting lugs

of the elevator trim tab actuator, part

number (P/N) 159SCC100–1 and –5; and

2. shimming to correct any out-ofplane mounting. If cracking is detected during any

inspection, the AD requires that the

actuator be replaced with an actuator

having P/N 159SCC100–1, –5, or –11.

(AD 72–24–04 specifies that, if an

actuator having P/N 159SCC100–11 is

installed, no further action is required.)

That action was prompted by a report

indicating that, during an inspection, all

four mounting lugs on a Gulfstream G–

159 elevator trim tab actuator were

found to be cracked. Examination of the

actuator unit indicated that two of the

lugs had been failed for an

undetermined period of time.

Additional inspections of other

airplanes revealed numerous fittings

with one lug failed and some with two

lugs failed.

Once one lug fails, the adjacent lug is

under twice the normal stress, and will

eventually fail. At that point, the

remaining two lugs are being worked in

bending and their remaining service life,

in this condition, is short.

The requirements of that AD are

intended to detect cracked lugs as early

as possible so as to prevent the

concurrent failure of the four lugs. Such

failure could cause severe vibration

during flight and/or reduction or loss of

elevator trim tab capability; this could

then result in reduced controllability of

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

reviewed selected customer bulletins

and aircraft service changes, 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. 191, dated

August 18, 1972, for mandatory

rulemaking action. This service change

describes procedures for replacing the

elevator trim tab actuators having P/N

159SCC100–1 or –5, with actuators

having P/N 159SCC100–11. The

replacement actuators have new,

increased strength housings, and are not

susceptible to the type of cracking that
10232 Federal Register / Vol. 62, No. 44 / Thursday, March 6, 1997 / Proposed Rules

was previously found. Installation of

these new actuators eliminates the need

for the repetitive inspections for

cracking.

The group recognized the fact that

cracks in the existing elevator trim tab

actuator housings are very difficult to

identify, even with the dye penetrant, if

they are small or have just started.

Therefore, installation of the improved

actuators will positively address the

identified unsafe condition by

eliminating the potential both for the

cracking itself, as well as for cracks that

are missed during an inspection.

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 72–24–04. It would

continue to require the repetitive dye

penetrant inspections for cracks in the

elevator trim tab actuator mounting

lugs. However, it would also require the

installation of improved actuators,

which would constitute terminating

action for the repetitive inspections. The

installation would be required to be

accomplished in accordance with the

aircraft service change described

previously.

FAA’s Determination for the Need to

Mandate the Installation

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

emphasis on design improvements. The

proposed installation 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 72–24–04 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 new installation 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 $4,900 per airplane.

Based on these figures, the cost impact

of the proposed requirements of this AD

on U.S. operators is estimated to be

$404,640, or $5,620 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.

39.13 [Amended]

2. Section 39.13 is amended by

removing amendment 39–1559 (37 FR

24419, November 17, 1972), and by

adding a new airworthiness directive

(AD), to read as follows:

Gulfstream Aerospace Corporation

(previously Grumman): Docket 97–NM–

15–AD. Supersedes AD 72–24–04,

amendment 39–1559.

Applicability: Model G–159 (G–I)

airplanes, on which elevator trim tab

actuators having part number 159SCC100–11

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 (e)(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 elevator trim tab

mounting lugs due to cracking, which could

result in severe vibration during flight and a

consequent reduction or loss of elevator trim

tab capability, accomplish the following:

(a) Within 10 hours time-in-service after

November 24, 1972 (the effective date of AD

72–24–04, amendment 39–1559), perform an

inspection to detect cracks in the mounting

lugs of the elevator trim tab actuators, having

part number (P/N) 159SCC100–1 or –5; and

shim to correct any out-of-plane condition, in

accordance with Gulfstream Customer

Bulletin No. 208A through Amendment 2,

dated April 21, 1972, and Operational

Summary No. 72–5B, dated August 1972.

(b) If no crack is found in any mounting

lug during the inspection required by

paragraph (a) of this AD, repeat the

inspection at intervals not to exceed 200

hours time-in-service.

(c) If any crack is found in a mounting lug

when conducting any inspection required by

paragraph (a) or (b) of this AD, prior to

further flight, replace the elevator trim tab

actuator with a new or serviceable actuator

having P/N 159SCC100–1, –5, or –11.

(1) If an actuator having P/N 159SCC100–

1 or –5 is used as the replacement unit,

repeat the inspection for cracks specified in

paragraph (a) of this AD thereafter at

intervals not to exceed 200 hours time-inservice.

(2) If an actuator having P/N 159SCC100–

11 is used as the replacement unit, no further

inspection action is required for that unit in

accordance with this AD.

(d) Within 1,000 hours time-in-service after

the effective date of this AD, replace the
Federal Register / Vol. 62, No. 44 / Thursday, March 6, 1997 / Proposed Rules 10233

elevator trim tab actuators with actuators that

have P/N 159SCC100–11, in accordance with

Gulfstream Aircraft Service Change No.191,

dated August 18, 1972. This installation

constitutes terminating action for the

inspections required by this AD.

(e)(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

72–24–02, amendment 39–1559, are

approved as alternative methods of

compliance with this AD.

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 February

27, 1997.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–5460 Filed 3–5–97; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 96–CE–25–AD]

RIN 2120–AA64

Airworthiness Directives; Pilatus

Britten-Norman Ltd. (formerly BrittenNorman) BN–2A, BN–2B, and BN–2T

Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes to

adopt a new airworthiness directive that

would apply to Pilatus Britten-Norman

Ltd. (Pilatus Britten-Norman) BN–2A,

BN–2B, and BN–2T series airplanes.

The proposed AD would require

repetitively inspecting the junction of

the torque link lug and upper case of the

main landing gear (MLG) torque link

assemblies for cracks, and replacing any

MLG torque link assembly with a

Modification A39 MLG torque link

assembly, either immediately when

cracks are found or after a certain period

of time if cracks are not found.

Replacing all MLG torque link

assemblies with Modification A39 MLG

torque link assemblies would eliminate

the need for the repetitive inspections.

These proposed repetitive inspections

are currently required by AD 86–07–02

for the BN–2A, BN–2B, and BN–2T

series airplanes, as well as the BN2A

MK. 111 series airplanes. There are no

improved design parts for the BN2A

MK. 111 series airplanes. The Federal

Aviation Administration (FAA) is

issuing in a separate action a proposed

revision to AD 86–07–02 to retain the

repetitive inspection and replacement

(if cracked) requirements for the BN2A

MK. 111 series airplanes. The actions

specified in the proposed AD are

intended to prevent failure of the main

landing gear caused by cracks in the

torque link area, which could lead to

loss of control of the airplane during

landing operations.

DATES: Comments must be received on

or before May 12, 1997.

ADDRESSES: Submit comments on the

proposal in triplicate to the FAA,

Central Region, Office of the Assistant

Chief Counsel, Attention: Rules Docket

No. 96–CE–25–AD, Room 1558, 601 E.

12th Street, Kansas City, Missouri

64106. Comments may be inspected at

this location between 8 a.m. and 4 p.m.,

Monday through Friday, holidays

excepted.

Service information that applies to the

proposed AD may be obtained from

Pilatus Britten-Norman Limited,

Bembridge, Isle of Wight, United

Kingdom PO35 5PR; telephone 44–1983

872511; facsimile 44–1983 873246. This

information also may be examined at

the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Mr.

Tom Rodriguez, Program Officer,

Brussels Aircraft Certification Division,

FAA, Europe, Africa, and Middle East

Office, c/o American Embassy, B–1000

Brussels, Belgium; telephone (32 2)

508.2717; facsimile (32 2) 230.6899; or

Mr. S.M. Nagarajan, Project Officer,

Small Airplane Directorate, Airplane

Certification Service, FAA, 1201

Walnut, Suite 900, Kansas City,

Missouri 64106; telephone (816) 426–

6932; facsimile (816) 426–2169.

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

should 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 that

summarizes 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 No. 96–CE–25–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, Central Region, Office of the

Assistant Chief Counsel, Attention:

Rules Docket No. 96–CE–25–AD, Room

1558, 601 E. 12th Street, Kansas City,

Missouri 64106.

Discussion

The FAA has determined that reliance

on critical repetitive inspections on

aging commuter-class airplanes carries

an unnecessary safety risk when a

design change exists that could

eliminate or, in certain instances,

reduce the number of those critical

inspections. In determining what

inspections are critical, the FAA

considers (1) the safety consequences if

the known problem is not detected

during the inspection; (2) the

probability of the problem not being

detected during the inspection; (3)

whether the inspection area is difficult

to access; and (4) the possibility of

damage to an adjacent structure as a

result of the problem.

These factors have led the FAA to

establish an aging commuter-class

aircraft policy that requires

incorporating a known design change

when it could replace a critical

repetitive inspection. With this policy

in mind, the FAA conducted a review

of existing AD’s that apply to Pilatus

Britten-Norman BN–2A, BN–2B, BN–2T,

and BN2A MK. 111 series airplanes.

Assisting the FAA in this review were

(1) Pilatus Britten-Norman; (2) the

Regional Airlines Association (RAA); (3)

the Civil Aviation Authority of the