9796 Federal Register / Vol. 60, No. 35 / Wednesday, February 22, 1995 / Proposed Rules

WIPL–SD–0049, WIPL–SD–0051 through

WIPL–SD–0065, WIPL–SD–0067, WIPL–

SD–0070, WIPL–SD–0071,

SDJ10883, SDJ10884A, SDJ10884B, and

SDJ10886 through SDJ10891

(1) To ensure that a part number SP28E4

taper pin is installed, visually inspect the

passenger/crew door locking mechanism in

the area between the locking dog and

indicator button assembly in accordance with

Part 2 of the Accomplishment Instructions

section of Jetstream Service Bulletin (SB) 52–

A–JA 911140, which incorporates the

following pages:

Pages Revision level Date

4, 5, 7, and 9 Original Issue February 3,

1992.

2 ................... Revision 1 .... June 26,

1992.

1, 3, 6, and 8 Revision 2 .... October 6,

1992.

(2) If a taper pin (part number SP28E4) is

not installed, prior to further flight,

accomplish Part 3 of the Accomplishment

Instructions section of Jetstream SB 52–A–JA

911140.

(b) For all affected airplanes regardless of

the serial number passenger door installed,

modify the passenger door warning system in

accordance with the Accomplishment

Instructions section of Jetstream SB 52–JM

7793, which incorporates the following

pages:

Pages Revision level Date

4 through 11 Original Issue November

19, 1992.

1, 2, and 3 ... Revision 1 .... August 10,

1993.

Note 1: Compliance with a previous

revision level of the service bulletins

referenced in this AD fulfills the applicable

requirements of this AD and is considered

‘‘unless already accomplished’’ for that

portion of the AD.

(c) 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.

(d) An alternative method of compliance or

adjustment of the compliance times that

provides an equivalent level of safety may be

approved by the Manager, Brussels Aircraft

Certification Office (ACO), FAA, Europe,

Africa, and Middle East Office, c/o American

Embassy, B–1000 Brussels, Belgium. The

request should be forwarded through an

appropriate FAA Maintenance Inspector,

who may add comments and then send it to

the Manager, Brussels ACO.

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Brussels ACO.

(e) All persons affected by this directive

may obtain copies of the documents referred

to herein upon request to Jetstream Aircraft

Limited, Manager Product Support,

Prestwick Airport, Ayrshire, KA9 2RW

Scotland; telephone (44–292) 79888; or

Jetstream Aircraft Inc., Librarian, P.O. Box

16029, Dulles International Airport,

Washington, DC, 20041–6029; or may

examine these documents at the FAA,

Central Region, Office of the Assistant Chief

Counsel, Room 1558, 601 E. 12th Street,

Kansas City, Missouri 64106.

Issued in Kansas City, Missouri, on

February 14, 1995.

Barry D. Clements,

Manager, Small Airplane Directorate, Aircraft

Certification Service.

[FR Doc. 95–4252 Filed 2–21–95; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 94–NM–254–AD]

Airworthiness Directives; Lockheed

Model L–1011–385 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

Lockheed Model L–1011–385 series

airplanes. This proposal would require

modifications of various fluid drainage

areas of the fuselage. This proposal is

prompted by incidents involving

corrosion and fatigue cracking in

transport category airplanes that are

approaching or have exceeded their

economic design goal; these incidents

have jeopardized the airworthiness of

the affected airplanes. The actions

specified by the proposed AD are

intended to prevent degradation of the

structural capabilities of the affected

airplanes due to problems associated

with corrosion.

DATES: Comments must be received by

April 17, 1995.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 94–NM–

254–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

Lockheed Aeronautical Systems

Support Company, Field Support

Department, Dept. 693, Zone 0755, 2251

Lake Park Drive, Smyrna, Georgia

30080. 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, Small Airplane Directorate,

Campus Building, 1701 Columbia

Avenue, Suite 2–160, College Park,

Georgia.

FOR FURTHER INFORMATION CONTACT:

Thomas Peters, Flight Test Branch,

ACE–160A, FAA, Atlanta Aircraft

Certification Office, Small Airplane

Directorate, Campus Building, 1701

Columbia Avenue, Suite 2–160, College

Park, Georgia 30337–2748; telephone

(404) 305–7367; 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 94–NM–254–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.

94–NM–254–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

In April 1988, a high-cycle transport

category airplane (specifically, a Boeing

Model 737) was involved in an accident

in which the airplane suffered major

structural damage during flight.
Federal Register / Vol. 60, No. 35 / Wednesday, February 22, 1995 / Proposed Rules 9797

Investigation of this accident revealed

that the airplane had numerous fatigue

cracks and a great deal of corrosion.

Subsequent inspections conducted by

the operator on other high-cycle

transport category airplanes in its fleet

revealed that other airplanes had

extensive fatigue cracking and

corrosion.

Prompted by the data gained from this

accident, the FAA sponsored a

conference on aging airplanes in June

1988, which was attended by

representatives from the aviation

industry and airworthiness authorities

from around the world. It became

obvious that, because of the tremendous

increase in air travel, the relatively slow

pace of new airplane production, and

the apparent economic feasibility of

operating older technology airplanes

rather than retiring them, increased

attention needed to be focused on the

aging airplane fleet and maintaining its

continued operational safety.

The Air Transport Association (ATA)

of America and the Aerospace

Industries Association (AIA) of America

agreed to undertake the task of

identifying and implementing

procedures to ensure the continued

structural airworthiness of aging

transport category airplanes. An

Airworthiness Assurance Working

Group (AAWG) was established initially

in August 1988, with members

representing aircraft manufacturers,

operators, regulatory authorities, and

other aviation industry representatives

worldwide. The objective of the AAWG

was to sponsor ‘‘Task Groups’’ to:

1. select service bulletins, applicable

to each airplane model in the transport

fleet, to be recommended for mandatory

modification of aging airplanes;

2. develop corrosion-directed

inspections and prevention programs;

3. review the adequacy of each

operator’s structural maintenance

program;

4. review and update the

Supplemental Inspection Documents

(SID); and

5. assess repair quality.

The L–1011 Structures Task Group,

which was assigned by the AAWG to

review the Lockheed Model L–1011–385

series airplanes, completed its work on

Item 2 in 1991 and developed a baseline

program for controlling corrosion

problems that may jeopardize the

continued airworthiness of the Model

L–1011 fleet. The program is contained

Lockheed Document Number LR 31889,

‘‘Corrosion Prevention and Control

Program, TriStar L–1011,’’ dated March

15, 1991.

The FAA reviewed and approved that

Document and, on October 8, 1993,

issued AD 93–20–03, amendment 39–

8710 (58 FR 60775, November 18, 1993),

which is applicable to all Lockheed

Model L–1011 series airplanes. That AD

requires the implementation of a

corrosion prevention and control

program (CPCP), comparable to the one

outlined in the Lockheed Document,

either by accomplishing specific tasks or

by revising the FAA-approved

maintenance inspection program to

include such a program.

Current Service Information

Since issuance of AD 93–20–03, the

FAA has reviewed and approved

Revision A of Lockheed Document

Number LR 31889, ‘‘Corrosion

Prevention and Control Program, TriStar

L–1011,’’ dated April 1994. This

revision of the Lockheed Document

contains Section 7.2, which lists twelve

Lockheed service bulletins that have

been recommended for mandatory

action by the L–1011 Structures Task

Group.

The twelve Lockheed service bulletins

recommended by the Task Group

describe various modifications,

installations, and inspections of the

fuselage and wings that are intended to

decrease the airplane’s susceptibility to

corrosion in specific areas. The

pertinent Lockheed service bulletins

are:

1. Service Bulletin 093–51–007,

Revision 5, dated December 20, 1973,

describes procedures for modifying the

afterbody-emennage-wing area to

improve drainage capability.

2. Service Bulletin 093–53–061,

Revision 1, dated June 20, 1974,

describes procedures for modifying the

drainage provisions at the surround

structure of the C–1, C–2, and C–3 cargo

doors.

3. Service Bulletin 093–53–068, dated

October 23, 1974, describes procedures

for installing a drain at the C–1A cargo

door sill.

4. Service Bulletin 093–53–095,

Revision 2, dated June 22, 1987,

describes procedures for installing

additional provisions for drainage at the

pressure deck of the nose landing gear.

5. Service Bulletin 093–53–113, dated

November 12, 1975, describes

procedures for a modifying the area of

the stringers at Fuselage Station (FS)

1792 to improve fluid drainage.

6. Service Bulletin 093–53–157, dated

May 3, 1977, describes procedures for

inspecting and modifying the sealing

and drainage provisions at the aft

pressure bulkhead.

7. Service Bulletin 093–53–186,

Revision 3, dated June 11, 1991,

describes procedures for the installing

additional drainage provisions in the

fuselage drain system.

8. Service Bulletin 093–53–192,

Revision 2, dated December 9, 1981,

describes procedures for modifying the

fuselage drain system.

9. Service Bulletin 093–53–204,

Revision 1, dated March 26, 1984,

describes procedures for modifying the

door sill drain and cargo compartment

beam at the galley and door

compartments.

10. Service Bulletin 093–53–234,

Revision 2, dated November 12, 1992,

describes procedures for modifying the

galley door sill area to improve

corrosion resistance.

11. Service Bulletin 093–57–089,

Revision 1, dated October 4, 1976,

describes procedures for installing drain

provisions and a dam in the main

landing gear torque box.

12. Service Bulletin 093–57–138,

Revision 1, dated July 17, 1981, and

Change Note, dated September 3, 1982,

describe procedures for inspecting the

lower surface bolts at wing body line

(WBL) 115.95 to detect corrosion, and

necessary modification.

The FAA has considered the

recommendation of the Task Group and

concurs with it. The FAA has

determined that accomplishment of the

actions specified in the twelve

Lockheed service bulletins will

contribute to positively addressing the

unsafe condition presented by the

problems associated with corrosion.

Proposed Requirements of AD

Since corrosion is likely to exist or

develop on airplanes of this type design,

an AD is proposed which would require

the accomplishment of the modification,

installation, and other actions specified

in the twelve Lockheed service bulletins

described previously.

Although the proposed AD would be

a rulemaking action completely separate

from AD 93–20–03, the compliance

schedule for the accomplishment of the

proposed actions would be consistent

with that for the corrosion inspections

(tasks) currently required by AD 93–20–

03. The initial corrosion tasks required

by AD 93–20–03 must be accomplished

within various intervals of time,

depending on what ‘‘airplane zone’’ is

involved; the intervals are measured

from a date one year after the effective

date of that AD. Accordingly, since the

effective date of AD 93–20–03 is

‘‘December 17, 1993,’’ the schedule for

the actions currently required by that

AD is measured from December 17,

1994.

This proposed AD would require

accomplishment of the proposed

modifications, installations, and
9798 Federal Register / Vol. 60, No. 35 / Wednesday, February 22, 1995 / Proposed Rules

inspections at the same time that the

initial corrosion task in the

corresponding airplane zone is required

by AD 93–20–03. Scheduling the

proposed actions at the same time as the

currently-required corrosion tasks will

minimize additional work for affected

operators by allowing them to perform

all actions concurrently. This also will

eliminate the necessity of operators

having to gain access to subject areas

more than once.

Additionally, certain of the

modifications described in the twelve

Lockheed service bulletins were

incorporated previously on some

airplanes during production. For such

cases, no additional work would be

required by this proposed AD.

Economic Impact Information

There are approximately 241 Model

L–1011–385 series airplanes of the

affected design in the worldwide fleet.

The FAA estimates that 117 airplanes of

U.S. registry would be affected by this

proposed AD. It would take

approximately 236 work hours per

airplane to accomplish the proposed

actions, including time to gain access

and close up. The average labor rate is

currently $60 per work hour. Based on

these figures, the total cost impact of the

proposed AD on U.S. operators is

estimated to be $1,656,720, or $14,160

per airplane.

The total 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. However, as

indicated previously, some airplanes

that would be subject to the proposed

AD were modified during production to

incorporate certain of the proposed

modifications and installations. In light

of this, the total cost impact of this

proposal would be considerably less

that the figure discussed above.

Additionally, the number of required

work hours for the proposed

requirements of this AD, as indicated

above, is presented as if the

accomplishment of those actions were

to be conducted as ‘‘stand alone’’

actions. However, in actual practice,

these actions would be accomplished

coincidentally or in combination with

actions currently required by AD 93–

20–03. Therefore, the actual number of

necessary ‘‘additional’’ work hours will

be minimal for the majority of affected

operators.

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. App. 1354(a), 1421

and 1423; 49 U.S.C. 106(g); and 14 CFR

11.89.

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

Lockheed: Docket 94–NM–254–AD.

Applicability: All Model L–1011–385

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

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 use the authority

provided in paragraph (b) to request approval

from the FAA. This approval may address

either no action, if the current configuration

eliminates the unsafe condition; or different

actions necessary to address the unsafe

condition described in this AD. Such a

request should include an assessment of the

effect of the changed configuration on the

unsafe condition addressed by this AD. In no

case does the presence of any modification,

alteration, or repair remove any airplane from

the applicability of this AD.

Compliance: Required as indicated, unless

accomplished previously.

To prevent structural failure due to the

problems associated with corrosion

accomplish the following:

(a) Accomplish the modifications,

installations, and inspections described in

the Lockheed service bulletins listed in

Section 7.2 of Lockheed Document Number

LR 31889, ‘‘Corrosion Prevention and Control

Program, TriStar L–1011,’’ Revision A, dated

April 1994 (hereafter referred to as ‘‘the

Document’’), in accordance with the

following schedule:

Note 2: Airplanes on which the

modifications, installations, and inspections

required by this paragraph have been

accomplished prior to the effective date of

this AD or during production are considered

to be in compliance with this paragraph.

Note 3: Airplanes on which the

modifications, installations, and inspections

required by this paragraph have been

accomplished previously in accordance with

an earlier version of the applicable service

bulletin listed in Section 7.2 of the

Document, are considered to be in

compliance with this paragraph.

Note 4: ‘‘Airplane zones,’’

‘‘implementation ages,’’ and ‘‘repeat

intervals,’’ as referred to in this paragraph,

are specified in Section 4.3 of the Document.

(1) For modifications, installations, and

inspections located in an airplane zone that

has not yet exceeded the ‘‘implementation

age’’ (IA) for that zone as of December 17,

1994 (one year after the effective date of AD

93–20–03, amendment 39–8710): Compliance

is required no later than the IA plus the

repeat (R) interval for the applicable zone.

(2) For modifications, installations, and

inspections located in an airplane zone that

has exceeded the IA for that zone as

December 17, 1994: Compliance is required

within one R interval for that zone, measured

from December 17, 1994.

(3) For airplanes that are 20 years old or

older as of December 17, 1994:

Accomplishment of the modifications,

installation, and inspections is required

within one R interval for the applicable

airplane zone, but not to exceed 6 years,

measured from December 17, 1994,

whichever occurs first.

(b) 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), ACE–

115A, 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.

Note 5: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Atlanta ACO.
Federal Register / Vol. 60, No. 35 / Wednesday, February 22, 1995 / Proposed Rules 9799

(c) 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

15, 1995.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 95–4253 Filed 2–21–95; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 93–CE–61–AD]

Airworthiness Directives; Piper Aircraft

Corporation PA24, PA28R, PA30,

PA32R, PA32RT, PA34–200, PA34–

200T, PA39, and PA44 Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes to

adopt a new airworthiness directive

(AD) that would apply to certain Piper

Aircraft Corporation (Piper) PA24,

PA28R, PA30, PA32R, PA32RT, PA34–

200, PA34–200T, PA39, and PA44 series

airplanes. The proposed action would

require repetitively inspecting the main

gear side brace studs for cracks and

replacing any cracked main gear side

brace stud. Several reports of main gear

side brace stud cracks on the affected

airplanes, including seven incidents

where the main landing gear (MLG)

collapsed, prompted the proposed AD.

The actions specified by the proposed

AD are intended to prevent a MLG

collapse caused by main gear side brace

stud cracks, which, if not detected and

corrected, could result in loss of control

of the airplane during landing

operations.

DATES: Comments must be received on

or before May 5, 1995.

ADDRESSES: Submit comments in

triplicate to the FAA, Central Region,

Office of the Assistant Chief Counsel,

Attention: Rules Docket No. 93–CE–61–

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.

Information that relates to the

proposed AD may be inspected at the

Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT:

Christina Marsh, Aerospace Engineer,

FAA, Atlanta Aircraft Certification

Office, Campus Building, 1701

Columbia Avenue, Suite 2–160, College

Park, Georgia 30337–2748; telephone

(404) 305–7362; facsimile (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

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. 93–CE–61–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. 93–CE–61–AD, Room

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

Missouri 64106.

Discussion

The FAA has received several reports

of main gear side brace stud cracks on

Piper PA24, PA32R, PA34–200, and

PA34–200T series airplanes. These

reports include an accident in the

United Kingdom where the main

landing gear (MLG) collapsed on a Piper

PA34–200 series airplane because of

high cycle fatigue cracking of the main

gear side brace stud. Metallurgical

examination of the stud revealed that

separate fatigue cracks had originated

from both the inboard and the outboard

edges near the bending radius of the

shank. Reverse bending loads then

allowed these cracks to extend across

approximately 30-percent of the shank

cross-section. The remaining 70-percent

of the shank cross-section failed because

of overstress. Review of service

difficulty records in the United

Kingdom and Canada, as well as the

United States, indicated that this

accident was almost identical to other

accidents on Piper airplane models of

similar type design.

On February 11, 1994, the FAA issued

an advance notice of proposed

rulemaking (ANPRM) to solicit

comments from owners/operators of the

affected airplanes in order to adequately

make a determination as to what type of

action to take (if any). From responses

to this ANPRM, the FAA found that

most of the owners/operators that

responded are currently inspecting the

main gear side brace studs on a routine

basis (every annual or 100 hours);

however, these operators are not

removing the studs or using nondestructive inspection methods. Based

on its review of the above-referenced

incidents, the FAA has determined that,

in order to adequately detect any cracks

on the main gear side brace studs, these

studs must be removed and inspected

using dye penetrant or magnetic particle

methods.

After examining the circumstances

and reviewing all available information

related to the incidents and accidents

described above, including the

comments received in response to the

ANPRM, the FAA has determined that

AD action should be taken to prevent

MLG collapse caused by main gear side

brace stud cracks, which, if not detected

and corrected, could result in loss of

control of the airplane during landing

operations.

Since an unsafe condition has been

identified that is likely to exist or

develop in other Piper PA24, PA28R,

PA30, PA32R, PA32RT, PA34–200,

PA34–200T, PA39, and PA44 series

airplanes of the same type design, the

proposed AD would require repetitively

inspecting (using dye penetrant or

magnetic particle methods) the main

gear side brace studs for cracks, and

replacing any cracked main gear side

brace stud.

The FAA estimates that 9,200

airplanes in the U.S. registry would be

affected by the proposed AD, that it

would take approximately 5 workhours

to initially inspect both the right and

left main landing gear side brace studs,

and that the average labor rate is

approximately $60 an hour. Based on

these figures, the total cost impact of the

proposed AD on U.S. operators is

estimated to be $2,760,000. This figure

represents the cost of the initial

inspection, and does not reflect costs for