24304 Federal Register / Vol. 66, No. 93 / Monday, May 14, 2001 / Proposed Rules

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000–NM–350–AD]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 747 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 747 series

airplanes. This proposal would require

an inspection of the flap drive

transmission of the trailing edge flaps at

positions 2 and 7 to determine if a

wound-spring torque brake is installed,

and corrective action, if necessary. This

action is necessary to prevent damage to

the flap system, adjacent systems, or

structural components; or excessive

skew of the trailing edge flap, which

could result in flap asymmetry and

consequent reduced controllability of

the airplane. This action is intended to

address the identified unsafe condition.

DATES: Comments must be received by

June 28, 2001.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 2000–NM–

350–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. Comments may be

submitted via fax to (425) 227–1232.

Comments may also be sent via the

Internet using the following address: 9-

anm-nprmcomment@faa.gov. Comments

sent via fax or the Internet must contain

‘‘Docket No. 2000–NM–350–AD’’ in the

subject line and need not be submitted

in triplicate. Comments sent via the

Internet as attached electronic files must

be formatted in Microsoft Word 97 for

Windows or ASCII text.

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:

Barbara Mudrovich, Aerospace

Engineer, Systems and Equipment

Branch, ANM–130S, FAA, Seattle

Aircraft Certification Office, 1601 Lind

Avenue, SW., Renton, Washington

98055–4056; telephone (425) 227–2983;

fax (425) 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 action may be changed in light

of the comments received.

Submit comments using the following

format:

• Organize comments issue-by-issue.

For example, discuss a request to

change the compliance time and a

request to change the service bulletin

reference as two separate issues.

• For each issue, state what specific

change to the proposed AD is being

requested.

• Include justification (e.g., reasons or

data) for each request.

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 action

must submit a self-addressed, stamped

postcard on which the following

statement is made: ‘‘Comments to

Docket Number 2000–NM–350–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–114, Attention: Rules Docket No.

2000–NM–350–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The FAA has received a report that,

during overhaul of certain torque brakes

of the trailing edge flap transmissions

on certain Boeing Model 747 series

airplanes, the brakes did not lock out at

the intended torque levels. This has

been attributed to the actual lock-out

torque being higher than the design

levels. If the torque brake fails to limit

torque out of the transmission during a

flap jam condition, the resulting force

could cause the transmission mounts to

fail. Such failure of a transmission

mount on a transmission with a no-back

brake could push the flap into the wing,

which could result in a full flap

asymmetry. These conditions could

cause damage to the flap system,

adjacent systems, or structural

components; or excessive skew of the

trailing edge flap, and which could

result in flap asymmetry and

consequent reduced controllability of

the airplane.

Explanation of Relevant Service

Information

The FAA has reviewed and approved

Boeing Service Bulletin 747–27–2374,

dated November 18, 1999, which

describes procedures for inspection of

certain flap drive transmissions of the

trailing edge flaps at positions 2 and 7

to determine if a wound-spring torque

brake is installed, and corrective action,

if necessary. The corrective action

includes, but is not limited to,

replacement of the flap drive

transmission with a new, improved

transmission; and rework or

replacement of the torque brake

assembly with a new, improved

assembly, if a wound-spring torque

brake is installed.

The service bulletin references MOOG

Service Bulletin 544666–27–16, dated

November 1, 1999, as the source of

service information for accomplishment

of rework of the torque brake.

Accomplishment of the actions

specified in the service bulletin is

intended to adequately address the

identified unsafe condition.

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 accomplishment of the actions

specified in the service bulletin

described previously, except as

discussed below.

Differences Between This Proposed AD

and the Service Bulletin

Although the service bulletin

recommends doing the inspection at the

earliest convenient maintenance

opportunity, the FAA has determined

that this compliance time may not

Federal Register / Vol. 66, No. 93 / Monday, May 14, 2001 / Proposed Rules 24305

ensure that the identified unsafe

condition is addressed in a timely

manner. In developing an appropriate

compliance time for this proposed AD,

the FAA considered not only the

manufacturer’s recommendation, but

the degree of urgency associated with

addressing the subject unsafe condition,

the average utilization of the affected

fleet, and the time necessary to perform

the proposed AD. In light of all of these

factors, the FAA finds a compliance

time of 6,000 flight hours after the

effective date of this AD to be

warranted, in that it represents an

appropriate interval of time allowable

for affected airplanes to continue to

operate without compromising safety.

The service bulletin also recommends

replacement of the flap drive

transmission and/or torque brake of the

trailing edge flap transmission at

positions 2, 4, 5, and 7. The FAA has

determined that an unsafe condition

exists at positions 2 and 7 only. This

determination was made from a

probability assessment indicating that

positions 4 and 5 do not warrant

mandatory action because the likelihood

of failure of a torque brake to limit

torque out of the transmission during a

flap jam condition at these positions is

extremely remote. Additionally, full flap

asymmetry is not likely to occur at

positions 4 and 5. Therefore, this

proposed AD is applicable to positions

2 and 7 only.

Cost Impact

There are approximately 1,181

airplanes of the affected design in the

worldwide fleet. The FAA estimates that

263 airplanes of U.S. registry would be

affected by this proposed AD.

It would take approximately 1 work

hour per airplane to accomplish the

inspection, at an average labor rate of

$60 per work hour. Based on these

figures, the cost impact of the inspection

proposed by this AD on U.S. operators

is estimated to be $15,780, or $60 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 proposed AD were not adopted. The

cost impact figures discussed in AD

rulemaking actions represent only the

time necessary to perform the specific

actions actually required by the AD.

These figures typically do not include

incidental costs, such as the time

required to gain access and close up,

planning time, or time necessitated by

other administrative actions.

Regulatory Impact

The regulations proposed herein

would not have a substantial direct

effect 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,

it is determined that this proposal

would not have federalism implications

under Executive Order 13132.

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 2000–NM–350–AD.

Applicability: Model 747 series airplanes,

as listed in Boeing Service Bulletin 747–27–

2374, dated November 18, 1999; 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 (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 damage to the flap system,

adjacent systems, or structural components;

or excessive skew of the trailing edge flap;

which could result in flap asymmetry and

consequent reduced controllability of the

airplane, accomplish the following:

Part Verification/Replacement/Modification

(a) Within 6,000 flight hours after the

effective date of this AD: Inspect the flap

drive transmission of the trailing edge flaps

at positions 2 and 7 to determine if a woundspring torque brake is installed in the

transmission, by verifying the transmission

part number, per Boeing Service Bulletin

747–27–2374, dated November 18, 1999.

Then do the actions specified in paragraphs

(a)(1), (a)(2), (a)(3), and (a)(4) of this AD, as

applicable.

(1) If the part number of the flap drive

transmission shows that no wound-spring

torque brake is installed, no further action is

required by this AD.

(2) If the part number of the flap drive

transmission shows that a wound-spring

torque brake may be installed, before further

flight, inspect the part number of the torque

brake to verify whether it is a wound-spring

torque brake, per the Accomplishment

Instructions of the service bulletin.

(i) If the part number of the torque brake

shows that it is not a wound-spring torque

brake, no further action is required by this

AD.

(ii) If the part number of the torque brake

shows that it is a wound-spring torque brake,

before further flight, rework the torque brake

or replace the torque brake with a new,

improved brake, as applicable; per the

Accomplishment Instructions of the service

bulletin.

Spares

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

person shall install on any airplane any

transmission or torque brake assembly

identified in the ‘‘Existing Part Number’’

column of Paragraph 2.E. of Boeing Service

Bulletin 747–27–2374, dated November 18,

1999.

Alternative Methods of Compliance

(c) 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.

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.

Special Flight Permit

(d) Special flight permits may be issued in

accordance with sections 21.197 and 21.199

24306 Federal Register / Vol. 66, No. 93 / Monday, May 14, 2001 / Proposed Rules

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 May 8,

2001.

Donald L. Riggin,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 01–12008 Filed 5–11–01; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000–NM–351–AD]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 767–200 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 767–200 series

airplanes. This proposal would require

replacement of certain duct assemblies

of the air distribution system for the

flight compartment with new duct

assemblies with improved insulation,

and follow-on actions. This action is

necessary to prevent ignition of foam

insulation on the air distribution ducts,

which could result in a fire in the

airplane. This action is intended to

address the identified unsafe condition.

DATES: Comments must be received by

June 28, 2001.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 2000–NM–

351–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. Comments may be

submitted via fax to (425) 227–1232.

Comments may also be sent via the

Internet using the following address: 9-

anm-nprmcomment@faa.gov. Comments

sent via fax or the Internet must contain

‘‘Docket No. 2000–NM–351–AD’’ in the

subject line and need not be submitted

in triplicate. Comments sent via the

Internet as attached electronic files must

be formatted in Microsoft Word 97 for

Windows or ASCII text.

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: Don

Eiford, Aerospace Engineer, Systems

and Equipment Branch, ANM–130S,

FAA, Seattle Aircraft Certification

Office, 1601 Lind Avenue, SW., Renton,

Washington 98055–4056; telephone

(425) 227–2788; fax (425) 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 action may be changed in light

of the comments received.

Submit comments using the following

format:

• Organize comments issue-by-issue.

For example, discuss a request to

change the compliance time and a

request to change the service bulletin

reference as two separate issues.

• For each issue, state what specific

change to the proposed AD is being

requested.

• Include justification (e.g., reasons or

data) for each request.

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 action

must submit a self-addressed, stamped

postcard on which the following

statement is made: ‘‘Comments to

Docket Number 2000–NM–351–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–114, Attention: Rules Docket No.

2000–NM–351–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The FAA has received a report that an

operator found burned insulation on an

air distribution system duct located in

the Electronics and Electrical (E/E) bay.

The burned insulation was discovered

while the airplane was on the ground

when a maintenance crew noticed an

odor of burning. Investigation revealed

that the ignition source was an

overheated heater tape for the water

line. Polyurethane foam insulation

which was touching the water line

heater tape ignited and burned

completely. The foam had lost its

original fire-retardant properties. The

reason for the degradation of the foam’s

fire retardant properties is unknown;

however, contamination and aging of

the material are suspected. Ignition of

foam insulation on the air distribution

ducts could result in a fire in the

airplane.

Explanation of Relevant Service

Information

The FAA has reviewed and approved

Boeing Alert Service Bulletin 767–

21A0154, dated March 16, 2000, which

describes procedures for replacement of

certain duct assemblies of the air

distribution system for the flight

compartment (which are located under

the main deck) with new duct

assemblies having fiberglass insulation.

The service bulletin also describes

procedures for a general visual

inspection of the water line heater tape

where it passes close to the new duct

assembly to detect damage such as wear,

chafing, pinching, discoloration, or

localized burn marks. The service

bulletin specifies that any damaged tape

should be replaced with new heater

tape. If no damage is found, the service

bulletin specifies that any heater tape

that is too close to the new duct

assemblies must be rerouted to increase

the distance between the water line

heater tape and duct insulation.

Accomplishment of the actions

specified in the service bulletin is

intended to adequately address the

identified unsafe condition.

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 accomplishment of the actions

specified in the service bulletin