Federal Register / Vol. 62, No. 62 / Tuesday, April 1, 1997 / Proposed Rules 15435

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:

Boeing: Docket 96–NM–171–AD.

Applicability: Model 747–400, –400D, and

–400F series airplanes; as identified in

Boeing Alert Service Bulletin 747–21A2381,

dated June 27, 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 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 (b) 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 loss of control of the cabin

pressurization system, which could result in

rapid depressurization of the airplane and

consequent deleterious physiological effects

on the passengers and crew; and airplane

diversions, which represent an increased risk

to the airplane, passengers, and crew;

accomplish the following:

(a) Within 180 days after the effective date

of this AD, modify the P212 and P213 panels

of the cabin pressure control system as

specified in paragraph (a)(1) or (a)(2) of this

AD, as applicable, in accordance with Boeing

Alert Service Bulletin 747–21A2381, dated

June 27, 1996.

(1) For Groups 1 through 7 airplanes, as

identified in the alert service bulletin:

Change the wiring in the P212 and P213

panels; replace the existing two-pole relays

with new four-pole relays; and perform a test

of both panels.

(2) For Group 8 airplanes, as identified in

the alert service bulletin: Change the wiring

in the P212 panel; replace the existing twopole relays with new four-pole relays; replace

the existing P213 panel with a new P213

panel; and perform a test of both panels.

(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, Seattle

Aircraft Certification Office (ACO), 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, Seattle ACO.

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Seattle ACO.

(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 March

25, 1997.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–8129 Filed 3–31–97; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 97–NM–25–AD]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 767 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

certain Boeing Model 767 series

airplanes. This proposal would require

a one-time inspection of the main

landing gear (MLG) retaining bolt to

ensure that it is installed correctly, and

adjustments or repairs, if necessary.

This proposal is prompted by a report

indicating that a disconnected retaining

bolt was found in the MLG forward

trunnion joint of a Model 767 series

airplane. The actions specified by the

proposed AD are intended to prevent

aft-acting trunnion loads from being

transferred to the MLG beam, and

consequent fracture and collapse of the

MLG; this condition could result in the

loss of control of the airplane on the

ground.

DATES: Comments must be received by

May 9, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 97–NM–

25–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

Boeing Commercial Airplane Group,

P.O. Box 3707, Seattle, Washington

98124–2207.

This information may be examined at

the FAA, Transport Airplane

Directorate, 1601 Lind Avenue, SW.,

Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

James G. Rehrl, Aerospace Engineer,

Airframe Branch, ANM–120S, FAA,

Seattle Aircraft Certification Office,

1601 Lind Avenue, SW., Renton,

Washington; telephone (206) 227–2783;

fax (206) 227–1181.

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–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, Transport Airplane Directorate,

ANM–103, Attention: Rules Docket No.

97–NM–25–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.
15436 Federal Register / Vol. 62, No. 62 / Tuesday, April 1, 1997 / Proposed Rules

Discussion

Boeing notified the FAA that an

unsafe condition may exist on certain

Model 767 series airplanes. Boeing

advises that the FAA received a report

indicating that a disconnected retaining

bolt was found in the forward trunnion

joint of the main landing gear (MLG)

during the first ‘‘2C’’ check of a Model

767–300 series airplane. The inspection

revealed these findings:

1. The retaining bolt was found

jammed between the H-fitting and wing

rear spar.

2. The aft trunnion joint and MLG

beam did not show any damage.

3. The tabs of the retaining ring were

not engaged with the mating slots in the

bearing housing before the retaining bolt

was tightened into the outer cylinder of

the MLG. This allowed the retaining

bolt to turn and back out of the forward

trunnion threads.

The retaining bolt provides axial

retention of the spherical bearing in the

forward trunnion joint, which is the

design load path for transferring aftacting landing gear trunnion loads into

the wing rear spar H-fitting. If the

retaining bolt is disconnected, the aftacting trunnion loads are not transferred

by the design load path to the H-fitting

of the wing rear spar, but are instead

transferred to the MLG beam at the aft

trunnion joint. This condition, if not

corrected, could cause the MLG to

fracture and collapse, and could result

in the loss of control of the airplane on

the ground.

Explanation of Relevant Service

Information

The FAA has reviewed and approved

Boeing Alert Service Bulletin 767–

32A0157, dated October 10, 1996,

which describes procedures for a onetime inspection of the MLG retaining

bolt to ensure that it is installed

correctly, and adjustments or repairs, if

necessary. Accomplishment of these

procedures will preclude the aft-acting

landing gear trunnion loads from being

transferred to the MLG beam.

Explanation of Requirements of

Proposed Rule

Since an unsafe condition has been

identified that is likely to exist or

develop on other products of this same

type design, the proposed AD would

require a one-time inspection of the

MLG retaining bolt to ensure that it is

installed correctly, and adjustments or

repairs, if necessary. These actions

would be required to be accomplished

in accordance with the alert service

bulletin described previously.

Cost Impact

There are approximately 598 Boeing

Model 767 series airplanes of the

affected design in the worldwide fleet.

The FAA estimates that 151 airplanes of

U.S. registry would be affected by this

proposed AD, that it would take

approximately 5 work hours 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

$45,300, or $300 per airplane.

The 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.

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:

Boeing: Docket 97–NM–25–AD.

Applicability: Model 767 series airplanes,

line positions 1 through 600 inclusive, except

line positions 579 and 586; 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 (b) 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 aft-acting landing gear trunnion

loads from being transferred to the main

landing gear (MLG) beam, and consequent

fracture and collapse of the MLG and loss of

control of the airplane on the ground,

accomplish the following:

(a) Within 500 flight hours or 300 flight

cycles after the effective date of this AD,

whichever occurs later, perform a one-time

inspection of the MLG retaining bolt to

ensure that it is installed correctly, in

accordance with Boeing Alert Service

Bulletin 767–32A0157, dated October 10,

1996. If the retaining bolt is incorrectly

installed, prior to further flight, make

adjustments or repairs in accordance with the

alert service bulletin.

(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, Seattle

Aircraft Certification Office (ACO), 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, Seattle ACO.

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Seattle ACO.

(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.
Federal Register / Vol. 62, No. 62 / Tuesday, April 1, 1997 / Proposed Rules 15437

Issued in Renton, Washington, on March

25, 1997.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–8128 Filed 3–31–97; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 97–ANE–07]

RIN 2120–AA64

Airworthiness Directives; Pratt &

Whitney JT8D Series Turbofan Engines

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

Pratt & Whitney JT8D series turbofan

engines, that currently requires

inspections of low pressure turbine

(LPT) blade sets for blade shroud

crossnotch wear, and removal, if

necessary. In addition, the current AD

requires, as a terminating action to the

inspections, installation of improved

LPT containment hardware, and

installation of an improved No. 6

bearing scavenge pump bracket bushing.

This action would keep the compliance

actions of the current AD intact but

change the compliance time for full

compliance from the current calendar

end-date to December 31, 1998. This

proposal is prompted by a report of a

fourth stage hub manufacturing defect

that led to the failure of the hub and

subsequent release of LPT blades. The

actions specified by the proposed AD

are intended to prevent damage to the

aircraft resulting from engine debris

following an LPT blade, shaft, or hub

failure.

DATES: Comments must be received by

May 1, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), New England

Region, Office of the Assistant Chief

Counsel, Attention: Rules Docket No.

97–ANE–07, 12 New England Executive

Park, Burlington, MA 01803–5299.

Comments may also be sent via the

Internet using the following address: ‘‘9-

ad-engineprop@faa.dot.gov’’. Comments

sent via the Internet must contain the

docket number in the subject line.

Comments may be inspected at this

location between 8:00 a.m. and 4:30

p.m., Monday through Friday, except

Federal holidays.

The service information referenced in

the proposed rule may be obtained from

Pratt & Whitney, 400 Main St., East

Hartford, CT 06108; telephone (860)

565–6600, fax (860) 565–4503. This

information may be examined at the

FAA, New England Region, Office of the

Assistant Chief Counsel, 12 New

England Executive Park, Burlington,

MA.

FOR FURTHER INFORMATION CONTACT:

Christopher Spinney, Aerospace

Engineer, Engine Certification Office,

FAA, Engine and Propeller Directorate,

12 New England Executive Park,

Burlington, MA 01803–5299; telephone

(617) 238–7175, fax (617) 238–7199.

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

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–ANE–07.’’ 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, New England Region, Office of the

Assistant Chief Counsel, Attention:

Rules Docket No. 97–ANE–07, 12 New

England Executive Park, Burlington, MA

01803–5299.

Discussion

On September 22, 1994, the Federal

Aviation Administration (FAA) issued

airworthiness directive AD 94–20–08,

Amendment 39–9036 (59 FR 51842,

October 15, 1994), applicable to Pratt &

Whitney (PW) JT8D–1, –1A, –1B, –7,

–7A, –7B, –9, –9A, –11, –15, –17, and

–17R series turbofan engines, to require

inspections of low pressure turbine

(LPT) blade sets for blade shroud

crossnotch wear, and removal, if

necessary. In addition, the current AD

requires, as a terminating action to the

inspections, installation of improved

LPT containment hardware, and

installation of an improved No. 6

bearing scavenge pump bracket bushing.

That action was prompted by reports of

uncontained engine failures. That

condition, if not corrected, could result

in damage to the aircraft resulting from

engine debris following an LPT blade,

shaft, or hub failure.

Since the issuance of that AD, the

FAA has developed a two-part risk

management plan intended to address

the threat of blade release due to fourth

stage LPT hub failure. One part of the

management plan is a proposed rule,

Docket No. 96–ANE–32 (62 FR 1299,

January 9, 1997), which proposes the

initial and repetitive inspections and

removal from service of defective disks

in a suspect population. The other part

of the risk management plan is this

proposed AD, which reduces the threat

of uncontainment by changing the

compliance date of the current AD, 94–

20–08. The current AD addresses two

threats to uncontainment in a blade

failure and a shaft fracture by requiring

initial and repetitive inspections of

worn shroud crossnotches on third and

fourth stage LPT blades until improved

containment hardware can be installed.

To address the threat of shaft fracture,

the improved containment hardware

installation is required, as well as an

improved No. 6 bearing scavenge pump

bracket bushing to provide for better

rotor meshing. The compliance deadline

for incorporating the improved

containment hardware and the bearing

bracket bushing is currently December

31, 1999, or 7,000 cycles since

November 14, 1994, or 8,000 hours

since November 14, 1994, whichever

occurs later. To address the additional

threat of uncontainment in the form of

a fourth stage LPT hub fracture, which

results in a blade release, the calendar

end-date for completing compliance to

the requirements of the superseded AD

is changed to December 31, 1998, or

7,000 cycles since November 14, 1994,

or 8,000 hours since November 14,

1994, whichever occurs first.

The FAA has reviewed and approved

the technical contents of the following

service documents: PW ASB No. A5913,

Revision 6, dated October 15, 1993, that