This section of the FEDERAL REGISTER

contains regulatory documents having general

applicability and legal effect, most of which

are keyed to and codified in the Code of

Federal Regulations, which is published under

50 titles pursuant to 44 U.S.C. 1510.

The Code of Federal Regulations is sold by

the Superintendent of Documents. Prices of

new books are listed in the first FEDERAL

REGISTER issue of each week.

Rules and Regulations Federal Register

12739

Vol. 62, No. 52

Tuesday, March 18, 1997

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96–NM–67–AD; Amendment

39–9966; AD 97–06–09]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 737–300, –400, and –500 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–

300, –400, and –500 series airplanes.

This AD requires replacing certain

aileron/rudder trim control modules

with an improved module that contains

an improved rudder trim switch that

precludes the problems of sticking

associated with the existing switch. This

amendment is prompted by reports of

sticking conditions in the rudder trim

switch. The actions specified by this AD

are intended to prevent such sticking,

which could result in uncommanded

movement of the rudder and consequent

deviation of the airplane from its set

course.

DATES: Effective April 21, 1997.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of April 21,

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:

Hania Younis, Aerospace Engineer,

Systems and Equipment Branch, ANM–

130S, FAA, Seattle Aircraft Certification

Office, 1601 Lind Avenue, SW., Renton,

Washington; telephone (206) 227–2764;

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 737–300, –400, and –500 series

airplanes was published in the Federal

Register on October 3, 1996 (61 FR

51624). That action proposed to require

replacing the aileron/rudder trim

control module P8–43 with an improved

module that precludes the problems

associated with sticking that were

identified in the existing module.

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

Two commenters support the

proposed AD.

Request To Clarify Description of

Replacement Module

One commenter requests that the

FAA’s description of the replacement

module be revised to make it more

specific. This commenter points out that

the Summary and Discussion sections of

the preamble to the notice described the

replacement module as a ‘‘new model

that contains an improved rudder trim

switch to reduce internal friction.’’

However, the commenter states that the

new module incorporates a switch that

is of an entirely different design and,

therefore, accomplishes more than just

reduce friction. The new switch is much

simpler in design and is, therefore, more

reliable; the simpler design also

eliminates multiple causes of sticking

that have been identified in the existing

switch. The commenter suggests that the

description of the new module include

this information.

The FAA concurs that the

commenter’s description is more

specific. The FAA has revised the

descriptive language in the appropriate

portions of this preamble to the final

rule to include the commenter’s

suggested wording.

Request to Clarify Description of Unsafe

Condition

This same commenter requests that

the FAA’s description of the unsafe

condition, which appeared in the

Discussion section of the preamble to

the notice, be revised. The commenter

points to a sentence in that section that

stated, ‘‘If the trim switch sticks, it may

be prevented form returning to the

center position.’’ The commenter states

that this sentence would be more

accurate if stated as ‘‘If the trim switch

sticks, it may be prevented from

returning to the center position when

the switch knob is released.’’

The FAA does not concur. The FAA

does acknowledge that the majority of

incidents prompting this AD action

have involved switches that did not

return to the center position when the

switch knob was released. However,

according to the manufacturer, it is

possible that rudder pedals would be

required to control rudder movement;

i.e., it is possible that even returning the

switch to the center position manually

may not be effective. Therefore, the

commenter’s proposed wording would

not be accurate for all possible failure

scenarios.

Request to Change Proposed Actions

Altogether

One commenter, a non-U.S. operator,

requests that the proposal be revised by

eliminating the proposed actions

altogether because they will ‘‘only

generate additional maintenance costs

without affecting safety positively.’’

Instead, the commenter suggests that the

FAA propose requiring (1) a clearance

check between the rudder trim knob and

the control panel, and (2) restrictions on

food and beverages in the cockpit. This

commenter maintains that the main

cause of rudder trim runaways is due to

interference between the rudder trim

knob and the control panel, and, in most

cases, this interference is the result of

dirt (i.e., dust and food) collecting

beneath the knob and contaminating the

switches. In light of this, the commenter

considers that requiring a gap check and

a cleaning task would be a better course

of action.

The FAA does not concur. While a

gap check and cleaning task would be

effective in removing contamination

once it occurs, the newly designed
12740 Federal Register / Vol. 62, No. 52 / Tuesday, March 18, 1997 / Rules and Regulations

module required by this AD will prevent

contamination of the switch. Therefore,

it eliminates the potential for the

circumstances prompting the unsafe

condition from developing, and does

not impose additional restrictions or

cleaning requirements.

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 as proposed.

Cost Impact

There are approximately 1,159 Boeing

Model 737–300, –400, and –500 series

airplanes of the affected design in the

worldwide fleet. The FAA estimates that

537 airplanes of U.S. registry will be

affected by this AD, that it will take

approximately 3 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 $1,063 per

airplane. Based on these figures, the cost

impact of the AD on U.S. operators is

estimated to be $667,491, or $1,243 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.

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

97–06–09 Boeing: Amendment 39–9966.

Docket 96–NM–67–AD.

Applicability: Model 737–300, –400, and

–500 series airplanes; as listed in Boeing

Alert Service Bulletin 737–27A1198, dated

June 6, 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 sticking conditions in the

rudder trim switch, which could result in

uncommanded movement of the rudder and

consequent deviation of the airplane from its

set course, accomplish the following:

(a) Within 2 years after the effective date

of this AD, replace the aileron/rudder trim

control module P8–43 having part number

(P/N) 69–73703–5 or 69–73703–6 with a new

aileron/rudder trim control module having P/

N 69–73703–8, in accordance with Boeing

Alert Service Bulletin 737–27A1198, dated

June 6, 1996.

(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.

(d) The replacement shall be done in

accordance with Boeing Alert Service

Bulletin 737–27A1198, dated June 6, 1996.

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.

(e) This amendment becomes effective on

April 21, 1997.

Issued in Renton, Washington, on March

10, 1997.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–6541 Filed 3–17–97; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 96–NM–26–AD; Amendment

39–9969; AD 97–06–12]

RIN 2120–AA64

Airworthiness Directives; British

Aerospace Model BAe 146 and Avro

146–RJ Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment supersedes

two existing airworthiness directives

(AD), applicable to British Aerospace

Model BAe 146 and Avro 146–RJ series

airplanes, that currently require

inspections to detect cracking of the

upper main fitting of the nose landing

gear (NLG), and replacement or repair of

cracked parts, if necessary. Those

actions were prompted by reports of

cracking in the main fittings of the NLG.

This amendment requires that, for

certain airplanes, the inspections be

accomplished at reduced intervals. This

amendment is prompted by the results

of new analyses of the cracking that

were conducted by the manufacturer of

the NLG. The actions specified by this

AD are intended to prevent failure of the

main fitting, which could lead to

collapse of the NLG during landing.

DATES: Effective April 21, 1997.