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

10754

Vol. 62, No. 46

Monday, March 10, 1997

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96–CE–17–AD]

RIN 2120–AA64

Airworthiness Directives; Pilatus

Britten-Norman Ltd. BN–2, 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

(AD) that would apply to Pilatus

Britten-Norman Ltd. (Pilatus) BN–2,

BN–2A, BN–2B, and BN–2T series

airplanes. The proposed action would

require modifying the upper engine

mounting brackets on the wing front

spar as terminating action for the

repetitive inspections that were required

in AD 84–23–06, which is the subject of

a proposal to eliminate the Pilatus BN–

2, BN–2A, BN–2B, and BN–2T series

airplanes from its applicability in a

separate action. The proposed action is

prompted by several reports of cracks in

the upper engine mounting brackets and

a new terminating action to eliminate

the repetitive inspections for Pilatus

BN–2, BN–2A, BN–2B, and BN–2T

series airplanes. The actions specified

by the proposed AD are intended to

prevent the failure of the engine

mounting brackets on the wing mounted

engines which could possibly cause

structural failure of the airplane.

DATES: Comments must be received on

or before May 12, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Central Region,

Office of the Assistant Chief Counsel,

Attention: Rules Docket No. 96–CE–17–

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 Ltd., 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: Tom

Rodriguez, Project Engineer, FAA,

Brussels Aircraft Certification Division,

Europe, Africa, and Middle East Office,

c/o American Embassy, B–1000

Brussels, Belgium; telephone (322)

513.3830, ext. 2716; facsimile (322)

230.6899; or Mr. S. M. Nagarajan,

Project Officer, Small Airplane

Directorate, Aircraft Certification

Service, FAA, 1201 Walnut, suite 900,

Kansas City, Missouri 64105; 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–17–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–17–AD, Room

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

Missouri 64106.

Events Leading to the Proposed Action

The Civil Airworthiness Authority

(CAA), which is the airworthiness

authority for the United Kingdom (UK),

notified the FAA that an unsafe

condition may exist on Pilatus BN–2,

BN–2A, BN–2B, and BN–2T series

airplanes. The UK CAA reports cracking

in the upper engine mounting brackets

on the wing mounted engines attached

to the wing front spar. This condition,

if not detected and corrected, could

result in failure of the engine mounting

brackets of the wing mounted engines

and possible structural failure and loss

of control of the airplane.

The Pilatus BN–2, BN–2A, BN–2B,

and BN–2T series airplanes are included

in the applicability section of AD 84–

23–06. A proposal to remove these

airplanes from the applicability of AD

84–23–06 is being issued in a separate

revised Notice of Proposed Rulemaking.

The repetitive inspections that have

been required by AD 84–23–06 would

be terminated with a modifying action

that is only applicable to the BN–2, BN–

2A, BN–2B, and BN–2T series airplanes

in this proposed action.

The FAA’s Aging Aircraft Policy

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
Federal Register / Vol. 62, No. 46 / Monday, March 10, 1997 / Proposed Rules 10755

aircraft policy that requires

incorporating a known design change

when it could replace a critical

repetitive inspection.

Based on its aging commuter-class

aircraft policy and after reviewing all

available information, the FAA has

determined that AD action should be

taken to modify the upper engine wing

mounting brackets of the affected

airplanes to eliminate the repetitive

short-interval inspections, and to

prevent failure of the upper engine wing

mounting brackets on wing mounted

engines which could possibly cause

structural failure of the airplane.

Related Service Information

Pilatus issued Service Bulletin No.

BN–2/SB.61, Issue 5, dated December 9,

1981, which specifies procedures for

modifying the engine mounting brackets

on the wing mounted engines and

terminating the repetitive inspection

after accomplishing the modification.

The UK CAA classified these service

bulletins as mandatory and has issued

AD No. 0619 in order to assure the

continued airworthiness of these

airplanes in the United Kingdom.

FAA’s Determination

This airplane model is manufactured

in the United Kingdom and is type

certificated for operation in the United

States under the provisions of section

21.29 of the Federal Aviation

Regulations (14 CFR 21.29) and the

applicable bilateral airworthiness

agreement. Pursuant to this bilateral

airworthiness agreement, the UK CAA

has kept the FAA informed of the

situation described above. The FAA has

examined the findings of the UK CAA,

reviewed all available information

including the service information

referenced above, and determined that

AD action is necessary for products of

this type design that are certificated for

operation in the United States.

Since an unsafe condition has been

identified that is likely to exist or

develop in other Pilatus BN–2, BN–2A,

BN–2B, and BN–2T series airplanes of

the same type design registered in the

United States, the proposed AD would

require initially inspecting the upper

engine mounting brackets on the wing

mounted engines for:

(1) Cracks at the bolt-holes,

(2) Elongation of the bolt holes,

(3) Fretting within the holes,

(4) Cracks at the rivet holes,

(5) Distortion or delamination of the

lugs, and that

(6) The bearings are the correct length

and the bolts are not threadbound.

If there is no evidence of damage or

defects similar to any of the abovementioned items, continue to

repetitively inspect at regular intervals

until the accumulation of 2,000 hours

time-in-service after the effective date of

the proposed AD, at which time the

proposed AD would require

accomplishing Pilatus Modification NB/

M/1147.

If any damage or defects are found

similar to any of the six items

previously mentioned, prior to further

flight, the proposed action would

require accomplishing Pilatus

Modification NB/M/1147. This

modification consists of replacing

damaged brackets, bolts, and bushes

with parts of an improved design.

Accomplishing this modification is

considered a terminating action to the

proposed repetitive inspections.

Cost Impact

The FAA estimates that 112 airplanes

in the U.S. registry would be affected by

the proposed AD, that it would take

approximately 37 workhours per

airplane to accomplish the initial

inspection and modification, and that

the average labor rate is approximately

$60 an hour. Parts cost approximately

$800 per airplane to accomplish the

modification. Based on these figures, the

total cost impact of the proposed AD on

U.S. operators is estimated to be

$338,240 or $3,020 per airplane. This

figure is based on the initial inspection

and modification only. It does not take

into account the cost for the repetitive

inspections that may be incurred over

the life of the airplane until the

modification is accomplished. The FAA

has no way to determine the number of

owners/operators that may have already

accomplished the proposed action.

The Proposed Action’s Impact Utilizing

the FAA’s Aging Commuter Class

Aircraft Policy

The intent of the FAA’s aging

commuter airplane program is to ensure

safe operation of commuter-class

airplanes that are in commercial service

without adversely impacting private

operators. Of the approximately 112

airplanes in the U.S. registry that would

be affected by the proposed AD, the

FAA has determined that approximately

18 percent are operated in scheduled

passenger service by 11 different

operators. A significant number of the

remaining 82 percent are operated in

other forms of air transportation such as

air cargo and air taxi.

The proposed AD allows 2,000 hours

time-in-service (TIS) after the effective

date of the proposed AD before

mandatory accomplishment of the

design modification. The average

utilization of the fleet for those

airplanes in commercial commuter

service is approximately 25 to 50 hours

TIS per week. Based on these figures,

operators of commuter-class airplanes

involved in commercial operation

would have to accomplish the proposed

modification within 5 to 10 calendar

months after the proposed AD would

become effective. For private owners,

who typically operate between 100 to

200 hours TIS per year, this would

allow 5 to 10 years before the proposed

modification would be mandatory.

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 action (1) is not a

‘‘significant regulatory action’’ under

Executive Order 12866; (2) is not a

‘‘significant rule’’ under 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 has been placed 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.
10756 Federal Register / Vol. 62, No. 46 / Monday, March 10, 1997 / Proposed Rules

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding a new airworthiness directive

(AD) to read as follows:

Pilatus Britten-Norman Ltd.: Docket No. 96–

CE–17–AD.

Applicability: Models BN–2 (serial

numbers 1 through 2033), BN–2T (serial

numbers 419, and 2030 through 2033), and

Models BN–2A and BN–2B (serial numbers 1

through 2116), 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 (g) 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 within the next 500

hours time-in-service (TIS) after the last

compliance with AD 84–23–06, or within the

next 100 hours TIS after the effective date of

this AD, whichever occurs later, unless

already accomplished.

To prevent failure of the upper mounting

brackets on both wing mounted engines

which could possibly cause structural failure

of the airplane, accomplish the following:

(a) Inspect the upper mounting brackets,

bolts, and bushings on both wing mounted

engines for:

(1) Cracks at the bolt holes,

(2) Elongation of the bolt holes,

(3) Fretting within the bolt holes,

(4) Cracks at the rivet holes,

(5) Distortion or delamination of the lugs,

and

(6) Correct bearing length and inspect for

bolts that are threadbound, in accordance

with the ‘‘ACTION—Inspection’’ section in

Pilatus Britten-Norman (Pilatus) Service

Bulletin (SB) No. BN–2/SB.61, Issue 5, dated

December 9, 1981.

(b) If the inspection reveals any evidence

of damage or defects similar to the items in

paragraphs (a)(1) through (a)(6), prior to

further flight, accomplish Pilatus

Modification NB/M/1147 by replacing the

brackets, bushes, and bolts with brackets

(part number (P/N) NB–20–D–7165), bushes

(P/N NB–20–A4–7171), and bolts of

improved design in accordance with

paragraphs 1, 2, 3, and 5 of the ‘‘ACTION—

Rectification/Modification’’ section in Pilatus

SB No. BN–2/SB.61, Issue 5, dated December

9, 1981.

(c) If damage or defects are found on just

one of the two brackets on each engine, then

both brackets must be replaced, prior to

further flight, in accordance with paragraph

1 of the ‘‘ACTION—Rectification/

Modification’’ section in Pilatus SB No. BN–

2/.SB.61, Issue 5, dated December 9, 1981.

(d) If no damage or defects are found

similar to the items in paragraphs (a)(1)

through (a)(6) of this AD, continue to inspect

at intervals not to exceed 500 hours TIS until

the accumulation of 2,000 hours TIS after the

effective date of this AD, at which time

Modification NB/M/1147 must be

accomplished on both upper mounting

brackets on both engines in accordance with

paragraphs 1, 2, 3, and 5 of the ‘‘ACTION—

Rectification/Modification’’ section of Pilatus

SB No. BN–2/SB.61, Issue 5, dated December

9, 1981.

(e) Accomplishing Modification NB/M/

1147 in the ‘‘ACTION—Rectification/

Modification’’ section of Pilatus SB No. BN–

2/SB.61, Issue 5, dated December 9, 1981, is

considered terminating action to the

repetitive inspections required in paragraph

(d) of this AD.

(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.

(g) An alternative method of compliance or

adjustment of the initial or repetitive

compliance times that provides an equivalent

level of safety may be approved by the

Manager, Brussels Aircraft Certification

Division, Europe, Africa, and Middle East

Office, c/o American Embassy, B–1000

Brussels, Belgium or the Manager, Small

Airplane Directorate, 1201 Walnut, suite 900,

Kansas City, Missouri 64106. The request

shall be forwarded through an appropriate

FAA Maintenance Inspector, who may add

comments and then send it to the Manager,

Brussels Aircraft Certification Division or the

Small Airplane Directorate.

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Brussels Aircraft

Certification Division or the Small Airplane

Directorate.

(h) All persons affected by this directive

may obtain copies of the document referred

to herein upon request to Pilatus BrittenNorman Ltd., Bembridge, Isle of Wight,

United Kingdom PO35 5PR; or may examine

this document 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 28, 1997.

Michael Gallagher,

Manager, Small Airplane Directorate, Aircraft

Certification Service.

[FR Doc. 97–5846 Filed 3–7–97; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 84–CE–18–AD]

RIN 2120–AA64

Airworthiness Directives; Pilatus

Britten-Norman Ltd. BN–2, BN–2A, BN–

2B, BN–2T, and BN–2A Mk 111 Series

Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes to

revise 84–23–06, which currently

requires repetitively inspecting the

upper mounting brackets, bolts, and

bushings on wing mounted engines for

cracks, wear, and insufficient fit on

certain Pilatus Britten-Norman Ltd.

(Pilatus) BN–2, BN–2A, BN–2B, BN–2T,

and BN–2A Mk 111 series airplanes,

and replacing any cracked, worn, or illfitting part. The proposed action would

retain the same action required in AD

84–23–06, except the action would only

be applicable to the BN–2A Mk 111

series airplanes. The proposed action is

prompted by a terminating modification

only applicable to the Pilatus BN–2,

BN–2A, BN–2B, BN–2T series airplanes

that would remove them from the

applicability of AD 84–23–06. The

actions specified by the proposed AD

are intended to prevent failure of the

upper mounting brackets on wing

mounted engines which could possibly

cause structural failure of the airplane.

DATES: Comments must be received on

or before May 12, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Central Region,

Office of the Assistant Chief Counsel,

Attention: Rules Docket No. 84–CE–18–

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 (322) 508–2715; facsimile

(322) 230–6899;

or

Mr. S. M. Nagarajan, Project Officer,

Small Airplane Directorate, Aircraft

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