Federal Register / Vol. 62, No. 43 / Wednesday, March 5, 1997 / Rules and Regulations 9925

Certification Procedures Issues Group

(Part 21), Parts & Production Working

Group is currently developing a draft

notice of proposed rulemaking (NPRM),

for submittal to the FAA, addressing the

approval of replacement and

modification parts. This issue is under

consideration; changes could be

incorporated into the forthcoming

NPRM.

Comment: Several commenters

expressed the desire to allow various

other categories of parts such as lamps

electrical connectors, and bearings.

FAA Response: The FAA’s Notice

solicited information as to the merits of

including categories of parts other than

discrete electrical or electronic

components under the interpretation.

The commenters did not state how the

conformity of the parts could be

established solely on the basis of

meeting a performance specification.

Thus, the FAA still regards the standard

parts exclusion as applicable to a

narrow segment of the entire population

of part designs.

Comment: One commenter expressed

the desire to allow programmable

devices to be considered standard parts

when there are approved pin-for-pin

alternatives. Such components only

become notionally non-standard after

programming for a specific application.

FAA Response: Programmable devices

were specifically excluded in the

proposed expanded interpretation

because their performance

characteristics may vary with the

instruction programmed within or

provided to such devices, or due to

different applied voltages and signals

affecting logical switching conditions.

Even though such devices may be pinto-pin compatible, the performance

characteristics cannot be assured, thus

making such devices ineligible for

consideration of the ‘‘performance’’

based interpretation of the definition.

The interpretation for standard parts

is effective on January 31, 1997. The

FAA is compiling a list of standard

setting bodies and U.S. government

entities that establish specifications for

standard parts. That list will be

published on the Aircraft Certification

Home Page on the World Wide Web by

June 30, 1997.

Issued in Washington, DC on January 31,

1997.

Elizabeth Yoest,

Deputy Director, Aircraft Certification

Service.

[FR Doc. 97–5437 Filed 3–4–97; 8:45 am]

BILLING CODE 4910–13–M

14 CFR Part 39

[Docket No. 96–NM–146–AD; Amendment

39–9953; AD 97–05–09]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 737 Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment adopts a

new airworthiness directive (AD),

applicable to certain Boeing Model 737

series airplanes, that requires

replacement of the flow restrictors of the

aileron and elevator power control units

(PCU’s) with new flow restrictors. This

amendment is prompted by a review of

the design of the flight control systems

on Model 737 series airplanes. The

actions specified by this AD are

intended to prevent reduced roll and/or

pitch rate control of the airplane and

consequent increased pilot workload as

a result of fragments from a deteriorated

flow restrictor filter screen becoming

lodged in the PCU.

DATES: Effective April 9, 1997.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of April 9,

1997.

ADDRESSES: The service information

referenced in this AD may be obtained

from Boeing Commercial Airplane

Group, P.O. Box 3707, Seattle,

Washington 98124–2207. This

information may be examined at the

Federal Aviation Administration (FAA),

Transport Airplane Directorate, Rules

Docket, 1601 Lind Avenue, SW.,

Renton, Washington; or at the Office of

the Federal Register, 800 North Capitol

Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Don

Kurle, Senior Engineer, Systems and

Equipment Branch, ANM–130S, FAA,

Transport Airplane Directorate, Seattle

Aircraft Certification Office, 1601 Lind

Avenue, SW., Renton, Washington

98055–4056; telephone (206) 227–2798;

fax (206) 227–1181.

SUPPLEMENTARY INFORMATION: A

proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39) to

include an airworthiness directive (AD)

that is applicable to certain Boeing

Model 737 series airplanes was

published in the Federal Register on

August 28, 1996 (61 FR 44232). That

action proposed to require replacement

of the flow restrictors of the aileron and

elevator power control units (PCU’s)

with new flow restrictors.

Interested persons have been afforded

an opportunity to participate in the

making of this amendment. Due

consideration has been given to the

comments received.

Support for the Proposal

One commenter supports the

proposed rule.

Request To Revise Statement of

Findings of Critical Design Review

Team

One commenter requests the second

paragraph of the Discussion section that

appeared in the preamble to the

proposed rule be revised to accurately

reflect the findings of the Critical Design

Review (CDR) team. The commenter

asks that the FAA delete the one

sentence in that paragraph, which read:

‘‘The recommendations of the team

include various changes to the design of

the flight control systems of these

airplanes, as well as correction of

certain design deficiencies.’’ The

commenter suggests that the following

sentences should be added: ‘‘The team

did not find any design issues that

could lead to a definite cause of the

accidents that gave rise to this effort.

The recommendations of the team

include various changes to the design of

the flight control systems of these

airplanes, as well as incorporation of

certain design improvements in order to

enhance its already acceptable level of

safety.’’

The FAA does not find that a revision

to this final rule in the manner

suggested by the commenter is

necessary, since the Discussion section

of a proposed rule does not reappear in

a final rule. The FAA acknowledges that

the CDR team did not find any design

issue that could lead to a definite cause

of the accidents that gave rise to this

effort. However, as a result of having

conducted the CDR of the flight control

systems on Boeing Model 737 series

airplanes, the team indicated that there

are a number of recommendations that

should be addressed by the FAA for

each of the various models of the Model

737. In reviewing these

recommendations, the FAA has

concluded that they address unsafe

conditions that must be corrected

through the issuance of AD’s. Therefore,

the FAA does not concur that these

design changes merely ‘‘enhance [the

Model 737’s] already acceptable level of

safety.’’

Request To Extend Compliance Time

for Replacing Flow Restrictors

Several commenters request that the

proposed compliance time for
9926 Federal Register / Vol. 62, No. 43 / Wednesday, March 5, 1997 / Rules and Regulations

replacement of the flow restrictors be

extended.

The Air Transport Association (ATA)

of America, on behalf of several of its

members, requests that the proposed

compliance time for accomplishment of

paragraph (a) of the proposal be

extended from within 18 months to

within five years after the effective date

of the AD to align with regularly

scheduled maintenance (‘‘D’’ checks).

One commenter requests that the

compliance time for paragraph (a) of the

proposal be extended to 24 months to

avoid grounding aircraft by scheduling

maintenance outside of regularly

scheduled visits. One ATA member

requests a 4-year compliance time based

on considerations including scheduling,

airplane downtime, unit turn-around

time, and availability of spare parts.

One commenter states that the retrofit

requires a 30-day turn-around time.

Another commenter indicates that

although the replacement takes 3 work

hours, it takes 42 total work hours to

return the airplane to service since the

affected units are CAT II sensitive line

replaceable units. The commenters also

point out that there has never been an

in-service failure of the filter screen.

The failure referenced in the proposal

occurred during a shop functional test at

5,400 pounds per square inch (psi) and,

in service, the unit would not be

subjected to operational pressures

greater than 3,000 psi. The commenters

add that there is some uncertainty at

this time as to whether the shop test

should be accomplished at such a high

pressure; such a test may cause more

safety concerns than it addresses.

One ATA member states that there is

no service history or other evidence to

indicate that the filter screens may fail

when subjected to 3,000 psi, nor is there

any history of discrepant PCU operation

attributed to failure of the filter screens.

The commenter indicates that the

affected PCU’s have accumulated an

average of 17,400 flight hours each (for

a total of approximately 17 million

flight hours) without an in-service

failure due to disintegration of the flow

restrictor filter screens. The commenter

believes that an acceptable level of

safety can be achieved by mandating the

replacement of suspect flow restrictors

at the next PCU overhaul, not to exceed

5 years after the effective date of the AD.

Boeing agrees that, in order to

preclude any failures from occurring

during a functional test following

maintenance action, the suspect PCU

filter screens should be replaced.

However, Boeing indicates that any

maintenance action involving removing,

disassembling, modifying, and

reinstalling the PCU provides

opportunity for a maintenance error. In

addition, Boeing states that any suspect

filter screens already installed in

airplanes are very unlikely to fail.

Boeing adds that there is added risk if

a filter screen failed during functional

testing, but was not discovered. In view

of these considerations, Boeing

recommends a compliance time of five

years or 15,000 hours.

One commenter, an operator of

affected airplanes of foreign registry,

requests that the proposed compliance

time be extended to 60 months to allow

sufficient time to accomplish the

replacement without grounding

airplanes.

The FAA concurs with the

commenters’ request to extend the

compliance time. The FAA has

determined that, in light of the

information presented by the

commenters, the compliance time can

be extended to five years or 15,000 flight

hours (whichever occurs first) to allow

the replacement to be performed at a

base during regularly scheduled

maintenance where special equipment

and trained maintenance personnel will

be available, if necessary. The FAA does

not consider that this extension will

adversely affect safety. Paragraph (a) of

the final rule has been revised to specify

the extended compliance time.

Request To Extend Compliance Time

for Disallowing Installation of Flow

Restrictors

The ATA also requests that the

proposed compliance time for

disallowing installation of flow

restrictors, as specified in paragraph (b)

of the proposal, be extended from ‘‘as of

the effective date of this AD’’ to within

two years after the effective date of the

AD. The commenter does not provide

specific justification for this request.

The FAA does not concur. Since the

service information referenced in this

final rule was issued in June 1992, the

FAA finds that ample opportunity has

been provided for removal of the

affected flow restrictors from operators’

inventories and replacement with

acceptable parts.

Requests To Withdraw the Proposal

Several commenters request that the

proposed rule be withdrawn.

One commenter believes the proposal

is not justified since it cannot be

supported by data. The commenter

indicates the proposal does not

contribute to improving the safety

aspects of Model 737 aircraft. The

commenter states that the Critical

Design Review (CDR) team’s report does

not indicate that there is any evidence

to tie the referenced service documents

to any in-service problems or accidents.

The commenter adds that the FAA has

not indicated that it has reviewed any

routine component tear-down reports

that would support the proposed

actions. The commenter concludes that

the FAA does not understand the

enormity of the proposed action.

A second commenter concludes that

the proposal does not address an unsafe

condition, even in a worst case

situation; that an unsafe condition is

extremely unlikely to occur in service;

and that an unsafe condition would

most likely be detected during a

preflight check.

Another commenter, Boeing, states

that the proposal does not correct an

unsafe condition; rather, it eliminates

the potential for a failure condition that

could degrade controllability (but not

prevent continued safe flight and

landing). Boeing indicates that there

have been no reported in-service

failures of the suspect filter screens.

Based on ‘‘the limited safety concern,’’

Boeing states that it is appropriate for

removal and rework of the suspect units

as part of routine maintenance. Boeing

suggests that, if the FAA does not

withdraw the proposal, the PCU

overhaul manual could be revised to

provide a procedure for inspection and

replacement of suspect flow restrictors.

One commenter states that both

Boeing and FAA analyses indicate a

worst case scenario (with an

accompanying independent hydraulic

failure) to be reversion to manual

control—a situation checked many

times each year during maintenance test

flights by carriers. The commenter also

states that the instance in which the

filter collapsed occurred at proof test

pressures that would never be

encountered in service (according to

Boeing and the component

manufacturer).

The FAA does not concur with these

requests to withdraw the proposed rule.

The FAA has not received any data to

demonstrate the reliability or strength of

the faulty filters. However, the FAA is

aware that these filters were not strong

enough to pass proof testing at the PCU

manufacturer’s facility. Neither the filter

or PCU manufacturer attempted to

quantify the actual strength of the filter

screen. In addition, while it is true that

there have been no reported in-service

failures, a screen failure would not

necessarily be reported since the FAA

does not require reports of screen

failures.

As discussed in the preamble to the

proposal, the FAA has determined that

sufficient data exist to demonstrate that

contamination of the PCU at the main

control valve due to deterioration of a
Federal Register / Vol. 62, No. 43 / Wednesday, March 5, 1997 / Rules and Regulations 9927

filter screen from a flow restrictor can

result in fragments of the screen

migrating to the main control valve, the

damping orifice, or the bypass valve.

Fragments from a deteriorated flow

restrictor filter screen could become

lodged in the PCU. As suggested by one

of the commenters, even if manual

reversion is checked during

maintenance test flights several times

each year, this condition is considered

unsafe since it would result in reduced

roll and/or pitch rate control of the

airplane and consequent increased pilot

workload. The FAA has determined that

replacement of the flow restrictors of the

aileron and elevator PCU’s with new

flow restrictors, as required by this AD

action, will adequately address that

unsafe condition.

The FAA has no objection to Boeing

revising the PCU overhaul manual to

provide a procedure for inspection and

replacement of suspect flow restrictors;

such revision will not affect the

requirements of this AD.

Request To Allow Records Search

One commenter requests that a note

be added to the proposal to specify that

compliance with the AD can be

demonstrated by accomplishing a

records search to determine whether

any of the suspect units are installed on

the airplane.

The FAA finds that no change to the

final rule is necessary. The applicability

of this final rule specifies that the AD

applies only to certain Model 737 series

airplanes that are equipped with an

aileron or elevator PCU having a

particular part number. This AD does

not preclude an operator from

performing a records search to

determine if an airplane in its fleet is

subject to the requirements of this AD.

Request To Revise Cost Impact

Information

One commenter states that imposition

of the proposal would overburden

competent repair facilities and expose

the airlines and the flying public to

unnecessary risk as a result. In support

of its position, the commenter states that

the cost impact information in the

proposal indicates the screens

referenced in the service letter cited in

the AD are line replaceable when they

are not. The commenter also asserts that

the costs specified in the proposal are

unrealistically low; however, the

commenter does not provide any

suggested cost estimates or data to

substantiate this remark.

The FAA infers from these remarks

that the commenter requests that the

cost impact information be revised. In

this case, the FAA does not concur.

First, the FAA points out that

comments are more likely to be

persuasive to the extent that they

provide specific and detailed

information regarding actual costs.

However, when commenters submit

simple generalizations about the costs,

there is little that the FAA can consider.

Second, the cost impact information,

below, describes only the ‘‘direct’’ costs

of the specific actions required by this

AD. The number of work hours

necessary to accomplish the required

actions and the cost for required parts

were provided to the FAA by the

manufacturer based on the best data

available to date. This number

represents the time necessary to perform

only the actions actually required by

this AD.

The FAA recognizes that, in

accomplishing the requirements of any

AD, operators may incur ‘‘incidental’’

costs in addition to the ‘‘direct’’ costs.

The FAA realizes that such is the case

for this AD, since the filter screen is not

a line replaceable unit. The cost analysis

in AD rulemaking actions, however,

typically does not include incidental

costs, such as the time required to gain

access and close up; planning time; or

time necessitated by other

administrative actions. Because

incidental costs may vary significantly

from operator to operator, they are

almost impossible to calculate.

Third, the FAA finds that the revised

compliance time specified in paragraph

(a) of this AD should allow ample time

for the required actions to be

accomplished coincidentally with

scheduled major airplane inspection

and maintenance activities, thereby

minimizing any burden on repair

facilities and any additional costs.

Conclusion

After careful review of the available

data, including the comments noted

above, the FAA has determined that air

safety and the public interest require the

adoption of the rule with the change

previously described. The FAA has

determined that this change will neither

increase the economic burden on any

operator nor increase the scope of the

AD.

Cost Impact

There are approximately 244 Model

737 series airplanes of the affected

design in the worldwide fleet. The FAA

estimates that 146 airplanes of U.S.

registry will be affected by this AD, that

it will take approximately 12 work

hours per airplane to accomplish the

required actions, and that the average

labor rate is $60 per work hour.

Required parts will cost approximately

$2,960 per airplane. Based on these

figures, the cost impact of the AD on

U.S. operators is estimated to be

$537,280, or $3,680 per airplane.

The cost impact figure discussed

above is based on assumptions that no

operator has yet accomplished any of

the 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 adopted herein will

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 final rule does

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)

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 final evaluation has

been prepared for this action and it is

contained in the Rules Docket. A copy

of it may be obtained from the Rules

Docket at the location provided under

the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation

safety, Incorporation by reference,

Safety.

Adoption of the Amendment

Accordingly, pursuant to the

authority delegated to me by the

Administrator, the Federal Aviation

Administration amends 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.
9928 Federal Register / Vol. 62, No. 43 / Wednesday, March 5, 1997 / Rules and Regulations

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

97–05–09 Boeing: Amendment 39–9953.

Docket 96–NM–146–AD.

Applicability: Model 737 series airplanes

equipped with an aileron or elevator power

control unit (PCU) having part number (P/N)

65–45180–29, serial numbers 182 through

1297 inclusive; certificated in any category.

Note 1: Originally, aileron or elevator

PCU’s having P/N’s and serial numbers

identified in the applicability of this AD may

have been installed on Model 737 series

airplanes having line numbers 1793 through

2036 inclusive. In addition, some of these

PCU’s may have been used as spares;

therefore, specific airplane line numbers

equipped with such PCU’s cannot be

provided in this AD.

Note 2: PCU’s having P/N 65–45180–29

consist of a PCU assembly having P/N 65–

44761–21 plus associated hydraulic fittings.

Both PCU P/N’s 65–45180–29 and 65–44761–

21 are serialized. PCU’s subject to the

requirements of this AD may be more easily

identified using serial numbers for P/N 65–

44761–21. The following serial numbers

correspond to P/N 65–44761–21:

8550A,

8552A,

8556A,

8557A,

8561A,

8563A through 8718A inclusive,

8720A through 8726A inclusive,

8728A through 8745A inclusive,

8749A,

8750A through 8758A inclusive,

8760A through 8873A inclusive,

8876A through 9004A inclusive,

9007A through 9012A inclusive,

9014A through 9040A inclusive,

9042A through 9066A inclusive,

9068A through 9340A inclusive,

9342A through 9388A inclusive,

9390A through 9529A inclusive,

9531A through 9676A inclusive, and

9678A through 9688A inclusive.

Note 3: 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 reduced roll and/or pitch rate

control of the aileron and consequent

increased pilot workload, accomplish the

following:

(a) Within 5 years or 15,000 flight hours

after the effective date of this AD, whichever

occurs first: Replace the four flow restrictors,

part number (P/N) JETA1875500D, on the

aileron and elevator power control units

(PCU’s), P/N 65–45180–29, serial numbers

182 through 1297 inclusive, with flow

restrictors having P/N JETX0527100B, in

accordance with Boeing Service Letter 737-

SL–27–71–A, dated June 19, 1992, including

Attachment 1.

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

person shall install a flow restrictor having

P/N JETA1875500D on an aileron or elevator

PCU having P/N 65–45180–29, serial

numbers 182 through 1297 inclusive, of any

airplane.

(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,

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 4: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Seattle ACO.

(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.

(e) The replacement shall be done in

accordance with Boeing Service Letter 737–

SL–27–71–A, dated June 19, 1992, including

Attachment 1. This incorporation by

reference was approved by the Director of the

Federal Register in accordance with 5 U.S.C.

552(a) and 1 CFR part 51. Copies may be

obtained from Boeing Commercial Airplane

Group, P.O. Box 3707, Seattle, Washington

98124–2207. Copies may be inspected at the

FAA, Transport Airplane Directorate, 1601

Lind Avenue, SW., Renton, Washington; or at

the Office of the Federal Register, 800 North

Capitol Street, NW., suite 700, Washington,

DC.

(f) This amendment becomes effective on

April 9, 1997.

Issued in Renton, Washington, on February

25, 1997.

James V. Devany,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–5158 Filed 3–4–97; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 71

[Airspace Docket No. 93–AEA–02]

Amendment to Class E Airspace;

Dunkirk, NY

AGENCY: Federal Aviation

Administration (FAA) DOT.

ACTION: Final rule.

SUMMARY: This amendment modifies the

Class E airspace at Dunkirk, NY, to

accommodate a Global Positioning

System (GPS) Standard Instrument

Approach Procedure (SIAP) to Runway

(RWY) 19 and a VHF Omni-Directional

Radio Range/Distance Measuring

Equipment (VOR/DME) SIAP to at

Angola Airport. The intended effect of

this action is to provide adequate

controlled airspace for instrument flight

rules (IFR) operations at the airport.

EFFECTIVE DATE: 0901 UTC, May 22,

1997.

FOR FURTHER INFORMATION CONTACT: Mr.

Francis Jordan, Airspace Specialist,

Operations Branch, AEA–530, Air

Traffic Division, Eastern Region, Federal

Aviation Administration, Federal

Building # 111, John F. Kennedy

International Airport, Jamaica, New

York 11430, telephone: (718) 553–4521.

SUPPLEMENTARY INFORMATION:

History

On January 6, 1995, the FAA

proposed to amend Part 71 of the

Federal Aviation Regulations (14 CFR

Part 71) by modifying Class E airspace

at Dunkirk, NY, (60 FR 2047). This

action would provide adequate Class E

airspace for IFR operations at Angola

Airport.

Interested parties were invited to

participate in this rulemaking

proceeding by submitting written

comments on the proposal to the FAA.

No comments objecting to the proposal

were received.

Class E airspace areas designations are

published in paragraph 6005 of FAA

Order 7400.9D, dated September 4,

1996, and effective September 16, 1996,

which is incorporated by reference in 14

CFR 71.1. The Class E airspace

designation listed in this document will

be published subsequently in the Order.

The Rule

This amendment to part 71 of the

Federal Aviation Regulations (14 CFR

part 71) modifies Class E airspace area

at Dunkirk, NY, to accommodate a GPS

RWY 19 SIAP, a VOR/DME or GPS A

SIAP and for IFR operations at Angola

Airport.

The FAA has determined that this

regulation only involves an established

body of technical regulations for which

frequent and routine amendments are

necessary to keep them operationally

current. Therefore, this regulation—(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 10034; February 26, 1979); and (3)

does not warrant preparation of a

regulatory evaluation as the anticipated

impact is so minimal. Since this is a