Federal Register / Vol. 62, No. 164 / Monday, August 25, 1997 / Proposed Rules 44917

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:

Aerospatiale: Docket 97-NM–161-AD.

Applicability: Model ATR42 series

airplanes as identified in Aerospatiale

Service Bulletin No. ATR42–32–0081, dated

July 16, 1996, and Aerospatiale Service

Bulletin No. ATR42–32–0082, dated July 16,

1996; 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 otherwise

modified, altered, or repaired so that the

performance of the requirements of this AD

is affected, the owner/operator must request

approval for an alternative method of

compliance in accordance with paragraph (d)

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 wear of the landing gear

attachment pins, which could result in

collapse of the main landing gear

(MLG), accomplish the following:

(a) Within 12 months after the

effective date of this AD, remove the

MLG leg hinge pins and side brace

assembly center pins having the part

numbers (P/N) specified in paragraph C.

(2) of Aerospatiale Service Bulletin No.

ATR42–32–0081, dated July 16, 1996;

and replace the pins with serviceable

pins, in accordance with the

Aerospatiale service bulletin and

Messier-Dowty Service Bulletin No.

631–32–127, Revision 1, dated October

22, 1996.

(b) Prior to the accumulation of

15,000 landings since the last overhaul

of the MLG, or within 8 years time-inservice since the last overhaul of the

MLG, whichever occurs first, remove

the MLG swinging lever/barrel pins and

shock absorber universal joint hinge

pins having the P/N’s specified in

paragraph C. (2) of Aerospatiale Service

Bulletin No. ATR42–32–0082, dated

July 16, 1996; and replace the pins with

serviceable pins, in accordance with the

Aerospatiale service bulletin and

Messier-Dowty Service Bulletin No.

631–32–128, dated November 15, 1996.

Note 2: Serviceable pins include those that

have been removed, inspected and marked

with green paint in accordance with MessierDowty Service Bulletin No. 631–32–127,

Revision 1, dated October 22, 1996; or

Messier-Dowty Service Bulletin No. 631–32–

128, dated November 15, 1996; as applicable.

(c) As of the effective date of this AD, no

person shall install any MLG pin having a

part number identified in Aerospatiale

Service Bulletin No. ATR42–32–0081, dated

July 16, 1996, or Aerospatiale Service

Bulletin No. ATR42–32–0082, dated July 16,

1996, on any airplane unless that pin is

considered to be serviceable in accordance

with the applicable service bulletin.

(d) 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,

Standardization Branch, ANM–113, FAA,

Transport 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, Standardization

Branch, ANM–113.

Note 3: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Standardization Branch,

ANM–113.

(e) Special flight permits may be issued in

accordance with sections 21.197 and 21.199

of the Federal Aviation Regulations (14 CFR

21.197 and 21.199) to operate the airplane to

a location where the requirements of this AD

can be accomplished.

Issued in Renton, Washington, on August

14, 1997.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–22043 Filed 8–22–97; 8:45 am]

BILLING CODE 4910–13–P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96–NM–189–AD]

RIN 2120–AA64

Airworthiness Directives; British

Aerospace BAe Model ATP 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

certain British Aerospace BAe Model

ATP airplanes. This proposal would

require a detailed visual inspection of

the flap drive torque tubes in the wing

root area to detect inadequate clearance

between the torque tubes and

surrounding structure or scoring damage

to the tubes; and follow-on repetitive

inspections or corrective action, if

necessary. Accomplishment of certain

replacements and modifications would

constitute terminating action for the

repetitive inspections. This proposal is

prompted by reports of inadequate

clearance between flap drive torque

tubes and surrounding structures, and

possible scoring damage to the tubes.

The actions specified by the proposed

AD are intended to prevent failure of the

torque tubes, which could result in an

asymmetric flap condition and reduced

controllability of the airplane.

DATES: Comments must be received by

October 6, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 96–NM–

189–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

AI(R) American Support, Inc., 13850

Mclearen Road, Herndon, Virginia

20171. This information may be

examined at the FAA, Transport

Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

William Schroeder, Aerospace Engineer,

Standardization Branch, ANM–113,

FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton,

Washington 98055–4056; telephone

(425) 227–2148; fax (425) 227–1149.

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
44918 Federal Register / Vol. 62, No. 164 / Monday, August 25, 1997 / Proposed Rules

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 96–NM–189–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.

96–NM–189–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The Civil Aviation Authority (CAA),

which is the airworthiness authority for

the United Kingdom, notified the FAA

that an unsafe condition may exist on

certain British Aerospace BAe Model

ATP airplanes. The CAA advises that,

following reports of restrictions of flight

control, a zonal survey was conducted

of all flying control circuits on these

airplanes. An area of reduced clearance,

which was identified between the wing

flap control system and wing center

section structure, was found to affect the

aluminum flap drive torque tubes. Such

inadequate clearance and consequent

scoring damage could lead to failure of

the torque tubes, and result in an

asymmetric flap condition and reduced

controllability of the airplane.

Explanation of Relevant Service

Information

The manufacturer has issued Service

Bulletin ATP–27–80, dated April 23,

1996, which describes procedures for a

detailed visual inspection of the flap

drive torque tubes in the wing root area

to detect inadequate clearance between

the torque tubes and surrounding

structure or scoring damage to the tubes;

and follow-on repetitive inspections, if

necessary. For certain cases, the service

bulletin also describes procedures for

the replacement of damaged torque

tubes with new tubes and modification

of the surrounding structure to gain

adequate clearance. Accomplishment of

such replacement and modification

would eliminate the need for the

repetitive inspections. The CAA

classified this service bulletin as

mandatory and issued British

airworthiness directive 003–04–96 in

order to assure the continued

airworthiness of these airplanes in the

United Kingdom.

FAA’s Conclusions

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 CAA has

kept the FAA informed of the situation

described above. The FAA has

examined the findings of the CAA,

reviewed all available information, and

determined that AD action is necessary

for products of this type design that are

certificated for operation in the United

States.

Explanation of Requirements of

Proposed Rule

Since an unsafe condition has been

identified that is likely to exist or

develop on other airplanes of the same

type design registered in the United

States, the proposed AD would require

a detailed visual inspection of the flap

drive torque tubes in the wing root area

to detect inadequate clearance between

the torque tubes and surrounding

structure or scoring damage to the tubes;

and follow-on repetitive inspections, if

necessary. For certain cases, this

proposal also would require the

replacement of damaged torque tubes

with new tubes and modification of the

surrounding structure to gain adequate

clearance. Accomplishment of the

modification would constitute

terminating action for the repetitive

inspection requirement of this AD.

These actions would be required to be

accomplished in accordance with the

service bulletin described previously.

Differences Between Proposed Rule and

Service Bulletins

Operators should note that Jetstream

Service Bulletin ATP–27–80, dated

April 23, 1996, differs from this AD in

two respects:

1. The service bulletin recommends

that, if inadequate clearance exists

between any flap drive torque tube and

surrounding structure in the wing root

area, and there is no scoring damage to

the tubes, the detailed repetitive visual

inspections of the tubes, at intervals not

to exceed 250 hours time-in-service,

may continue indefinitely. However, the

proposed AD would require

modification to achieve adequate

clearance within 2,000 hours time-inservice after the initial inspection. The

FAA has determined that long term

continued operational safety will be

better assured by modifications or

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

repetitive inspections, has led the FAA

to consider placing less emphasis on

special procedures and more emphasis

on design improvements. The proposed

modification requirement is in

consonance with these considerations.

2. The service bulletin recommends

that, if both torque tubes on the same

side are damaged, and the scoring is

within the maximum allowable damage

limits specified, continued flight is

allowed up to 250 hours time-in-service

before new torque tubes are installed.

However, the proposed AD would

require replacing at least one of the

torque tubes with a new tube prior to

further flight. The FAA has determined

that failure of both torque tubes on one

side during the same flight could result

in an asymmetric flap condition and

reduced controllability of the airplane.

The FAA also has determined that if

both torque tubes are damaged, even

though the damage on either torque tube

is within the allowable limits specified

in the service bulletin during repetitive

inspections, undetected residual

damage could propagate unexpectedly

and result in the failure of a torque tube.

Therefore, considering the possible

catastrophic results of an asymmetric

flap condition, this proposed AD

requires that at least one of the torque

tubes on the same side remains

undamaged at all times.

Cost Impact

The FAA estimates that 10 British

Aerospace BAe Model ATP airplanes of

U.S. registry would be affected by this

proposed AD, that it would take

approximately 1 work hour per airplane

to accomplish the proposed actions, and

that the average labor rate is $60 per

work hour. Based on these figures, the

cost impact of the proposed AD on U.S.

operators is estimated to be $600, or $60

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.
Federal Register / Vol. 62, No. 164 / Monday, August 25, 1997 / Proposed Rules 44919

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:

British Aerospace Regional Aircraft

[Formerly Jetstream Aircraft Limited,

ritish Aerospace (Commercial Aircraft)

Limited]: Docket 96–NM–189–AD.

Applicability: BAe Model ATP airplanes,

constructor numbers 2002 through 2063

inclusive; 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 (c) 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 torque tubes,

which could result in an asymmetric flap

condition and reduced controllability of the

airplane, accomplish the following:

(a) Within 90 days after the effective date

of this AD, conduct a detailed visual

inspection of the flap drive torque tubes in

the left and right wing root areas to detect

inadequate clearance between the torque

tubes and surrounding structure or scoring

damage to the tubes, in accordance with

Jetstream Service Bulletin ATP–27–80, dated

April 23, 1996.

(1) If adequate clearance exists between all

flap drive torque tubes and surrounding

structure at the sites specified in the service

bulletin, with no scoring damage to any of

the tubes, no further action is required by

this AD.

(2) If inadequate clearance exists between

any flap drive torque tube and surrounding

structure at the sites specified in the service

bulletin, with no scoring damage to the tubes:

Accomplish the requirements of paragraphs

(a)(2)(i) and (a)(2)(ii) of this AD.

(i) At intervals not to exceed 250 hours

time-in-service, repeat the detailed visual

inspections required by paragraph (a) of this

AD.

(ii) Within 2,000 hours time-in-service after

the initial inspection required by paragraph

(a) of this AD, modify the structure to gain

the required minimum clearance in

accordance with the service bulletin.

Accomplishment of the modification

constitutes terminating action for the

repetitive inspection requirement of

paragraph (a)(2)(ii) of this AD.

(3) If any scoring damage to the torque

tubes is detected, accomplish the

requirements specified in paragraph (a)(3)(i),

(a)(3)(ii), or (a)(3)(iii) of this AD, as

applicable, in accordance with the service

bulletin, and at the time specified in the

applicable paragraph.

(i) If only one torque tube on one side or

both sides of the airplane is damaged, and

the scoring is within the maximum allowable

damage limits in the service bulletin: Within

250 hours time-in-service after any

inspection required by this AD in which the

damage was initially detected, modify the

surrounding structure to gain the required

minimum clearance and install a new torque

tube.

(ii) If both torque tubes on the same side

of the airplane are damaged, and the scoring

is within the maximum allowable damage

limits in the service bulletin: Prior to further

flight after any inspection required by this

AD in which damage was initially detected,

modify the surrounding structure to gain the

required minimum clearance and replace at

least one of the damaged torque tubes with

a new torque tube. Within 250 hours timein-service after any inspection in which

damage was initially detected, replace the

remaining damaged torque tube with a new

torque tube.

(iii) If any torque tube is damaged, and the

scoring is more than the allowable damage

limits described in the service bulletin: Prior

to further flight, modify the surrounding

structure to gain the required minimum

clearance and replace the damaged tube(s)

with a new torque tube(s).

(b) Accomplishment of the modification to

gain the required minimum clearance

between the torque tubes and surrounding

structure and the replacement of damaged

torque tube(s) with a new torque tube(s)

constitutes terminating action for the

requirements of this AD.

(c) An alternative method of compliance or

adjustment of the initial compliance time

that provides an acceptable level of safety

may be used if approved by the Manager,

Standardization Branch, ANM–113, FAA,

Transport 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, Standardization

Branch, ANM–113.

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Standardization Branch,

ANM–113.

(d) 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 August

19, 1997.

S. R. Miller,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–22487 Filed 8–22–97; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 71

[Airspace Docket No. 97–AGL–34]

Proposed Modification of the Legal

Description of Class D Airspace; St.

Paul, MN, St. Paul Downtown Holman

Field

AGENCY: Federal Aviation

Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking.

SUMMARY: This notice proposes to

change the legal description of the Class

D airspace area at St. Paul Downtown

Holman Field (STP), St. Paul, NM. The

existing legal description of the airspace

area establishes the vertical limit of the

airspace at 3,200 feet Mean Sea Level

(MSL), excluding that airspace within