52486 Federal Register / Vol. 62, No. 195 / Wednesday, October 8, 1997 / Rules and Regulations

7. Newly-designated Section XII,

Secretarial Notification and

Consultation, is amended by revising

‘‘$100,000’’ to read ‘‘the statutory limit’’

in paragraph a.

[FR Doc. 97–26277 Filed 10–7–97; 8:45 am]

BILLING CODE 6560–50–P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96–NM–149–AD; Amendment

39–10116; AD 97–18–06]

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 all Boeing Model 737

series airplanes, that requires revising

the FAA-approved maintenance

program to prohibit the use of pressure

washing within the wheel well or on the

landing gear and to prohibit the use of

pumps and/or nozzles for washing

wheel wells or the landing gear; or

incorporation of a certain Temporary

Revision to the Boeing Airplane

Maintenance Manual into the FAAapproved maintenance program. 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 corrosion of certain

equipment due to the use of

inappropriate pressure washing

techniques. Corrosion of bearings,

cables, electrical connectors, or other

equipment in the main wheel well, if

not detected and corrected in a timely

manner, could result in reduced

controllability of the airplane.

DATES: Effective November 12, 1997.

The incorporation of reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of November

12, 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:

David Herron, Aerospace Engineer,

Systems and Equipment Branch, ANM–

130S, FAA, Transport Airplane

Directorate, Seattle Aircraft Certification

Office, 1601 Lind Avenue, SW., Renton,

Washington 98055–4056; telephone

(425) 227–2672; fax (425) 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 all Boeing Model

737 series airplanes was published in

the Federal Register on August 28, 1996

(61 FR 44239). That action proposed to

require revising the FAA-approved

maintenance program to prohibit the

use of pressure washing within the

wheel well or on the landing gear and

to prohibit the use of pumps and/or

nozzles for washing wheel wells or the

landing gear.

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

proposal.

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 Withdraw the Proposal:

Existing Procedures Are Adequate

Several commenters request that the

proposed rule be withdrawn since

pressure washing procedures exist that

adequately clean the wheel wells and

landing gear, yet provide protective

shielding for various components.

The FAA does not concur that this

final rule should be withdrawn for the

reason requested by the commenters.

Since the issuance of the proposal, the

FAA has reviewed and approved a new

Temporary Revision to the Airplane

Maintenance Manual (AMM), Chapter

12–40–0, that lists specific components

that require protection from exposure to

moisture. The Temporary Revision

describes procedures to shield and

protect these specific components from

moisture during pressure washing.

Therefore, the FAA has revised

paragraph (a) of this final rule to

provide an alternative method of

compliance for the requirements of this

AD by incorporating the Temporary

Revision into the AMM.

Request To Withdraw the Proposal: No

Supporting Data

Several commenters contend that

there are no data or records of in-service

findings that support the conclusion

that corrosion of the wheel wells or the

landing gear is induced by proper

pressure washing. One commenter

considers that the improper use of

pressure equipment, lack of protection

of critical areas, and improper

lubrication techniques are the more

significant and likely causes of any

corrosion occurring in the wheel well.

The commenter suggests that the

appropriate action to minimize the

possibility of corrosion is: proper

training of cleaning personnel, use of

proper equipment, protection of critical
Federal Register / Vol. 62, No. 195 / Wednesday, October 8, 1997 / Rules and Regulations 52487

areas, and proper lubrication

techniques.

The FAA does not concur that the

rule should be withdrawn for the

reasons presented by the commenters.

The FAA acknowledges that pressure

washing done correctly may not induce

corrosion of the wheel wells or the

landing gear. However, incorrect

pressure washing techniques of the

bearings, cables, electrical connectors,

and other equipment in the main wheel

well can result in fluids (or additives in

the fluids) being forced into these areas.

Such retention of fluid in these areas

can result in the development of

corrosion. Therefore, the FAA finds that

one method of preventing fluids from

being forced into certain areas is to

prohibit the use of pressure washing

within the wheel well or landing gear.

Request To Withdraw the Proposal:

Alternative Methods of Washing Are

Unsatisfactory

Several commenters state that

methods other than pressure washing do

not clean the area as well. The

commenters point out that surfaces of

the wheel wells or the landing gear that

are not adequately cleaned could

adversely affect the ability to perform

accurate structural inspections for

cracking. The commenters also contend

that hand washing of the wheel wells or

the landing gear would take

significantly more work hours to

accomplish than pressure washing and,

consequently, would be much more

costly to perform. The commenters

request that the proposal be withdrawn

since use of alternative methods of

washing are unsatisfactory.

The FAA does not concur that the

rule should be withdrawn for the

reasons presented by the commenters.

The FAA acknowledges that proper

pressure washing techniques provide

adequate cleaning of wheel wells and

landing gears, which enables structural

inspections for cracking to be performed

under optimum conditions. As stated

previously, the FAA has revised

paragraph (a) of this final rule, which

provides for pressure washing by

incorporation of the previously

described Temporary Revision into the

AMM as an alternative method of

compliance with the requirements of

this AD.

Request to Clarify the Prohibition of

Pressure Washing

Several commenters request that the

FAA clarify whether the proposed

prohibition of pressure washing would

include the use of de-icing fluids since

de-icing fluids are also applied with

pressure equipment. One commenter, an

operator, requests that de-icing be

specifically excluded from the

requirements of the proposed AD. The

commenter notes that it applies indirect

pressure spray to remove rime ice

buildup and other frozen accumulations

from the airplane. The commenter states

that there is a high potential for

anomalous operation if ice and grime

are not removed from the airplane.

Another operator requests that pressure

de-icing fluid be permitted when used

with a fan spray pattern, which the

operator asserts will reduce the impact

of the fluid on the airplane structure.

The FAA acknowledges that

clarification is appropriate. This AD

addresses procedures and limitations of

pressure washing as applicable only to

the cleaning of the airplane prior to

repair and inspection. Since de-icing

fluids are generally applied with a lower

pressure than pressure washing, and deicing normally impacts the ice directly,

rather than the sensitive components,

the FAA does not consider de-icing to

be encompassed within this rule.

However, if additional information

warrants further consideration of the

aspects of de-icing as related to pressure

application, the FAA may consider

additional rulemaking to address that

issue.

Request to Revise the Limit of 80

Pounds Per Square Inch, Gauge (PSIG)

Several commenters suggest that the

FAA has not given proper consideration

to the effects of impact pressure (force)

or momentum in determining the need

for a prohibition of use of pressure

equipment. One commenter points out

that impact pressure is a function of

flow rate and the square root of

pressure. This commenter states that

pressure psig is merely one component

of the force function. Another

commenter added that the temperature

of the spraying fluid should also be

considered since hot water or steam has

a much higher capability of dissolving

grease than cold water when applied at

the same pressure. Two other

commenters suggested the following

procedures to establish an appropriate

pressure limit: One procedure is to use

an equation that would establish an

impact pressure, and the other

procedure is to base the pressure limit

upon the pain threshold of impact on

the human hand.

The FAA does not concur that the

proposed pressure limit (80) psig should

be revised. The FAA established a

conservative figure based on water tap

pressure with an upper limit of 80 psig,

as provided by some municipalities.

The FAA has determined that with a

limitation of 80 psig during washing,

water and other contaminates such as

dirt are not likely to be driven into close

tolerance areas such as sealed bearings.

Therefore, if an operator elects to

eliminate pressure washing in order to

comply with the requirements of this

AD, 80 psig is an appropriate pressure

limit, since fluid would still be needed

to clean the wheel wells or landing gear.

Additionally, the FAA does not

concur with the commenters’ suggested

means of establishing a pressure limit.

The methods suggested by the

commenters provide no documentation

as to whether or not a pressure limit

established by either method proposed

would provide protection against water

and other contaminates such as dirt

from being driven into close tolerance

areas.

Request to Clarify Design Consideration

One commenter requests clarification

of the statement in the preamble of the

proposal indicating that ‘‘the FAA

concludes that these aircraft were

designed to operate with contaminate

buildup in the wheel wells and landing

gears.’’ The FAA concurs that

clarification of the impact of design

considerations is necessary. The

manufacturer has advised the FAA that

certain elements of the airplane design

are not readily changed. For example,

the feel and centering mechanism of the

aileron system has bearings that must be

oriented horizontally. That orientation

results in a pool of water/solvent and

debris accumulating on the top of

certain component equipment within

the wheel well.

Another commenter states that

pressure washing is comparable to the

airplane design to withstand the

momentum of rain droplets hitting gears

at 200 knots (which may be expected

with a Boeing Model 737 series airplane

during final approach). This commenter

further states that, while intense gear

and wheel well washing of the type

done during a C-check normally occurs

only once a year, airplanes could be

expected to fly through precipitation

with gear extended fifty or more times

a year.

The FAA does not concur that the

impact of rain is analogous to pressure

washing. While the design of the

airplane provides for the landing gear to

withstand the impact of rain, the wheel

well is located outside the streamline

flow. Consequently, rain pellets entering

the wheel well would be well below the

streamline velocity of the flow field

around the airplane. Therefore, the FAA

considers a certain amount of

contaminate buildup in the wheel wells
52488 Federal Register / Vol. 62, No. 195 / Wednesday, October 8, 1997 / Rules and Regulations

and landing gears to be an inherent

consideration of the design.

Request to Revise Estimated Cost

Several commenters (operators) state

that the estimated cost impact

information presented in the proposal is

clearly understated. These operators all

state, that instead of the estimated 5

work hours specified in the proposal to

perform the wheel well washings, it

would be more accurate and realistic to

estimate 40 or 50 work hours per

airplane for methods other than

pressure washing. The commenters state

that the expense of implementing this

type of corrective action is

inappropriate since pressure cleaning

done properly is, in itself, not a cause

of corrosion.

The FAA concurs that the cost impact

information, below, should be revised

based on information received from the

commenters. The FAA has revised this

information to specify 40 work hours to

perform the wheel well washings by

means other than pressure washing.

Additionally, the FAA has included cost

impact information of one work hour for

incorporating the Temporary Revision

into the AMM for those operators who

elect to accomplish this method of

complying with the requirements of this

AD.

Request to Clarify How Restricting

Pressure Washing Impacts

Controllability of the Airplane

One commenter requests clarification

on how pressure washing affects the

controllability of the airplane. The

operator points out that, in its

experience, no incidents have occurred

where the controllability of the airplane

has been compromised due to washing

of the landing gear.

The FAA acknowledges that

clarification is necessary. Corroded or

contaminated joints of the landing gear

could cause an increase in forces that

could adversely affect the actuation/

retraction of the landing gear or

movement of flight control surfaces

during flight. Additionally, damage

such as weakened seals due to erosion

or abrasion to hydraulic hoses or other

elements located on the landing gear

could further contribute to an adverse

effect on the controllability of the

airplane during flight and/or landing.

Therefore, the FAA finds that the failure

of bearings, cables, electrical

connectors, or other equipment in the

main wheel well, if not detected and

corrected in a timely manner, could

result in reduced controllability of the

airplane.

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 changes

previously described. The FAA has

determined that these changes will

neither significantly increase the

economic burden on any operator nor

increase the scope of the AD.

Cost Impact

There are approximately 2,463 Model

737 series airplanes of the affected

design in the worldwide fleet.

The FAA estimates that 1,040

airplanes of U.S. registry will be affected

by this AD, that it will take

approximately 40 work hours per

airplane to accomplish washing of the

wheel wells and landing gear by means

other than pressure washing, and that

the average labor rate is $60 per work

hour. If operators choose to comply with

this AD by prohibiting pressure

washing, the cost impact of the AD on

U.S. operators is estimated to be $2,400

per airplane, per washing.

If operators choose to comply with

this AD by incorporating a certain

Temporary Revision into the AMM, it

will take approximately 1 work hour per

airplane, at an average labor rate of $60

per work hour. Based on these figures,

the cost impact of U.S. operators is

estimated to be $60 per airplane.

The cost impact figures discussed

above are 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:

97–18–06 Boeing: Amendment 39–10116.

Docket 96–NM–149–AD.

Applicability: All Model 737 series

airplanes, 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 (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 corrosion in the bearings,

cables, electrical connectors, or other

equipment in the main wheel well, which

could result in reduced controllability of the

airplane, accomplish the following:

(a) Within 90 days after the effective date

of this AD, perform the requirements of

either paragraph (a)(1) or (a)(2) of this AD.

(1) Incorporate a revision into the FAAapproved maintenance program that

prohibits the use of pressure washing within

the wheel well or on the landing gear, and

that prohibits the use of pumps and/or

nozzles for washing wheel wells or the

landing gear. Pressure washing is defined as

the use of any fluid under pressure greater
Federal Register / Vol. 62, No. 195 / Wednesday, October 8, 1997 / Rules and Regulations 52489

than 80 pounds per square inch, gauge (psig);

or

(2) Incorporate the following Temporary

Revision(s) to Chapter 12 of the Boeing

Model 737 Airplane Maintenance Manual

(AMM), all dated February 7, 1997; as

applicable; into the FAA-approved

maintenance program.

Airplane model

Temporary

revision

No.

737–100/200 ................................... 12–368

12–369

12–370

12–371

12–372

12–373

737–300/–400/–500 ........................ 12–85

Note 2: Once an operator has incorporated

the above procedures into its maintenance

program, this AD does not require that the

operator subsequently record

accomplishment each time the wheel well is

cleaned. Future changes to the above

maintenance program require prior approval

of an appropriate FAA Principal

Maintenance Inspector (PMI).

(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 PMI, who may add

comments and then send it to the Manager,

Seattle ACO.

Note 3: 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) Except as specified in paragraph (a)(1)

of this AD, the actions shall be done in

accordance with the following Temporary

Revisions to Chapter 12 of the Boeing Model

737 Airplane Maintenance Manual.

Airplane model

Temporary

revision

No.

Dated

737–100/200 ...... 12–368 Feb. 7, 1997.

12–369 Feb. 7, 1997.

12–370 Feb. 7, 1997.

12–371 Feb. 7, 1997.

12–372 Feb. 7, 1997.

12–373 Feb. 7, 1997.

737–300/–400/–

500.

12–85 Feb. 7, 1997.

The 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.

(e) This amendment becomes effective on

November 12, 1997.

Issued in Renton, Washington, on August

25, 1997.

James V. Devany,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–24334 Filed 10–7–97; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96–SW–32–AD; Amendment

39–10151; AD 97–20–15]

RIN 2120–AA64

Airworthiness Directives; Hiller Aircraft

Corporation Model UH–12A, UH–12B,

UH–12C, UH–12D, and UH–12E

Helicopters

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment supersedes

an existing airworthiness directive (AD),

applicable to Hiller Aircraft Corporation

Model UH–12A, UH–12B, UH–12C,

UH–12D, and UH–12E helicopters, that

currently requires a dye penetrant

inspection of the head of the main rotor

outboard tension-torsion (T–T) bar pin

for cracks; a visual inspection of the

outboard T–T bar pin for proper

alignment and an adjustment, if

necessary; and, installation of shims at

the inboard end of the drag strut. This

amendment requires the same actions

required by the existing AD, but allows

a magnetic particle inspection of the T–

T bar pin as an alternative to the

currently required dye penetrant

inspection, and requires reporting the

results of the inspections only if cracks

are found, rather than reporting all

results of inspections as required by the

existing AD. This amendment is

prompted by an FAA analysis of a

comment to the existing AD, and the

fact that no cracks have been reported

since the issuance of the existing AD.

The actions specified by this AD are

intended to prevent cracks in the head

area of the outboard T–T bar pin, which

could result in loss of in-plane stability

of the main rotor blade and subsequent

loss of control of the helicopter.

DATES: Effective November 12, 1997.

The incorporations by reference of

certain publications listed in the

regulations were approved by the

Director of the Federal Register as of

June 23, 1995 (60 FR 30184, June 8,

1995).

ADDRESSES: The service information

referenced in this AD may be obtained

from Hiller Aircraft Corporation, 3200

Imjin Road, Marina, California 93933–

5101, telephone (408) 384–4500, fax

(408) 883–3648. This information may

be examined at the FAA, Office of the

Assistant Chief Counsel, 2601 Meacham

Blvd., Room 663, Fort Worth, Texas; or

at the Office of the Federal Register, 800

North Capitol Street, NW., suite 700,

Washington, DC.

FOR FURTHER INFORMATION CONTACT: Mr.

Charles Matheis, Aerospace Engineer,

FAA, Los Angeles Aircraft Certification

Office, 3960 Paramount Blvd.,

Lakewood, California 90712–4137,

telephone (562) 627–5235, fax (562)

627–5210.

SUPPLEMENTARY INFORMATION: A

proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39)

by superseding AD 95–12–02,

Amendment 39–9252 (60 FR 30184),

which is applicable to Hiller Model

UH–12A, UH–12B, UH–12C, UH–12D,

and UH–12E helicopters, was published

in the Federal Register on January 7,

1997 (62 FR 951). That action proposed

to require (1) an inspection of the

alignment of the outboard T–T bar pin

and an adjustment, if necessary; and (2)

an inspection for cracks in the head of

the outboard T–T bar pin using a dye

penetrant method or a magnetic particle

method. Additionally, that action

proposed to require, within 25 hours

TIS or at the next 100 hour inspection,

whichever occurs first, the installation

of shims between the inboard end of the

drag strut and the outboard T–T bar pin.

Interested persons have been afforded

an opportunity to participate in the

making of this amendment. Due

consideration has been given to the

comment received.

The one commenter states that AD

95–12–02 should be eliminated, and

that the requirement to report results of

each 100 hour TIS inspection to the

FAA should be discontinued, unless a

crack is found. The commenter states

that they have not experienced a T–T

bar pin failure in 30 years of service

history, and that if the procedures in the

manufacturer’s service information is

followed, the AD is not needed. The

FAA concurs that the reporting of the

inspection should be accomplished only

if the inspection reveals a crack.

However, the FAA does not concur that

the AD should be eliminated. The