Airworthiness Directives; Boeing Model 757-200 and -300 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-89-AD; Amendment 39-11435; AD 99-24-11]

RIN 2120-AA64

Airworthiness Directives; Boeing Model 757-200 and -300 Series

Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD),

applicable to certain Boeing Model 757-200 and -300 series airplanes,

that requires modification of the slide/raft evacuation system by

installing a girt reinforcement chafing patch. This amendment is

prompted by reports of holes in the inflatable area of the slide/raft

evacuation system due to chafing against the installation support

bracket. The actions specified by this AD are intended to prevent holes

in the inflatable portion of the slide/raft evacuation system, which

could result in the slide/raft being less effective as a raft during an

emergency water landing.

DATES: Effective January 4, 2000.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of January 4, 2000.

ADDRESSES: The service information referenced in this AD may be

obtained from Air Cruisers Company, Technical Publications Department,

P.O. Box 180, Belmar, New Jersey 07719-0180. 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: Keith Ladderud, Aerospace Engineer,

Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle

Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,

Washington 98055-4056; telephone (425) 227-2780; 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 certain Boeing Model 757-200 and -

300 series airplanes was published in the Federal Register on July 20,

1999 (64 FR 38846). That action proposed to require modification of the

slide/raft evacuation system by installing a girt reinforcement chafing

patch.

Comments

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 rule. One commenter states that

it is not affected by the proposed rule because its airplanes are not

equipped with the slide/rafts referenced in the proposal. Another

commenter states that it is in the process of accomplishing the actions

specified by Air Cruisers Company Service Bulletin 757-105-25-51, dated

January 29, 1999.

Request To Revise the Unsafe Condition

One commenter suggests that the unsafe condition cited in the

notice of proposed rulemaking (NPRM) be revised to state that holes

caused by the slide/raft chafing on the harness bracket could result in

the slide/raft being ``less effective'' as a raft during an emergency

water landing rather than ``unusable.'' The commenter contends that the

escape slide/rafts are designed with two independent inflation

chambers. Each independent chamber is capable of supporting the rated

occupancy of the slide/raft, and there have been no reports of holes in

both chambers.

The FAA concurs with the commenter's statement that the holes

caused by the slide/raft chafing against the bracket could result in

the slide/raft being ``less effective'' rather than ``unusable.'' Based

on reports that only one chamber of the slide/raft would be affected,

the FAA has determined that this change is appropriate and has changed

the final rule accordingly.

Request To Add an Inspection Requirement

One commenter states that an immediate inspection of the slide/

rafts is required to ensure that any slide/raft already chafed ``to the

point of failure'' be repaired immediately.

The FAA does not concur that an immediate inspection of the slide/

rafts is necessary. To date, the FAA has received only two reports of

chafing/scuffing of the slide/rafts that have resulted in a small hole

being worn through one of the two inflatable chambers. The FAA adds

that such a condition would result in a slow leak that would only

affect the rafting use of the escape slide/raft. In light of this, the

FAA has determined that accomplishment of paragraph (a) of this AD to

require modification of the slide/raft within 36 months after the

effective date of this AD is adequate in ensuring operational safety.

No change to the final rule is necessary in this regard.

Request To Revise Paragraph (a) of the Proposed Rule

One commenter questions the effectiveness of the proposed repair

(modification) action of adding a chafing patch, as specified by

paragraph (a) of the proposed AD, since that patch may cause wear of

another component, or simply delay the onset of a hole from wear. The

commenter states that ``a corrective action to eliminate the

interference and subsequent repetitive abrasion would seem more

appropriate in order to solve this problem.''

The FAA does not concur with the commenter's request to revise the

action (modification) required by paragraph (a) of the proposed AD.

Although the FAA acknowledges the concerns of the commenter regarding

corrective action to eliminate damage to the slide/raft, the FAA has

evaluated this modification for

[[Page 66755]]

its wear resistance and determined that modification of the slide/raft,

in accordance with the requirements of paragraph (a) of the AD, is

adequate to ensure the continued safety of the affected fleet.

Request To Extend the Compliance Time in Paragraph (b)

One commenter requests that the compliance time in paragraph (b) of

the proposed AD be extended from ``As of the effective date of this

AD'' to ``As of 30 days after the effective date of this AD.'' The

commenter contends that the compliance time should be extended to allow

additional time for obtaining the slide/raft spares and to ensure that

sufficient stock levels of those parts can be maintained.

The FAA does not concur with the commenter's request to extend the

compliance time in paragraph (b) of the proposed AD to 30 days. The FAA

considers that the specified compliance time allows sufficient time for

obtaining spares and maintaining stock levels. Further, the intent of

that paragraph is to prohibit the installation of spares that have been

determined to create an unsafe condition, and to simply require the use

of one part rather than another. In general, once an unsafe condition

has been determined to exist, it is the FAA's policy not to allow that

condition to be introduced into the fleet. When it is determined that

approved parts are immediately available to operators, the installation

of unsafe parts after the effective date of the AD is prohibited.

Further, the FAA considers that the period of time between publication

of the final rule AD in the Federal Register and the effective date of

the final rule (usually 30 days) is sufficient to provide operators

with an opportunity to determine their immediate need for modified

spares and to obtain them. However, in individual cases where this is

not possible, every AD contains a provision that allows an operator to

obtain an extension of compliance time based upon a specific showing of

need. The FAA considers that this policy does increase safety and does

not impose undue burdens on operators. Therefore, no change to the

final rule is necessary in this regard.

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

increase the economic burden on any operator nor increase the scope of

the AD.

Cost Impact

There are approximately 445 Model 757-200 and -300 series airplanes

of the affected design in the worldwide fleet. The FAA estimates that

310 airplanes of U.S. registry will be affected by this AD, that it

will take approximately 5 work hours per airplane to accomplish the

modification, and that the average labor rate is $60 per work hour.

Required parts will cost approximately $145 per airplane. Based on

these figures, the cost impact of the AD on U.S. operators is estimated

to be $137,950, or $445 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.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding the following new

airworthiness directive:

99-24-11 Boeing: Amendment 39-11435. Docket 99-NM-89-AD.

Applicability: Model 757-200 and -300 series airplanes, equipped

with Air Cruisers Company slide/raft evacuation systems having part

and serial numbers identified in Table 1 of this AD; certificated in

any category.

Table 1.--Air Cruisers Company Slide/Raft Evacuation Systems Subject to This AD

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Name Part No. Serial No.

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Air Cruisers............................ D30657-( )....................... Prior to 1132.

Air Cruisers............................ D30658-( )....................... Prior to 0859.

Air Cruisers............................ D30659-( )....................... Prior to 0860.

Air Cruisers............................ 61570-( )........................ Prior to 0321.

Air Cruisers............................ 61475-( )........................ Prior to 0137.

Air Cruisers............................ 61475-( )........................ 0138, 0139.

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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

[[Page 66756]]

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 holes in the inflatable portion of the slide/raft

evacuation system, which could result in the slide/raft being less

effective as a raft during an emergency water landing, accomplish

the following:

Modification

(a) Within 36 months after the effective date of this AD, modify

the slide/raft evacuation system in accordance with Air Cruisers

Company Service Bulletin 757-105-25-51, dated January 29, 1999.

Spares

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

a slide/raft evacuation system having a part number and serial

number identified in Table 1 of this AD, on any airplane, unless

that slide/raft evacuation system has been modified in accordance

with Air Cruisers Company Service Bulletin 757-105-25-51, dated

January 29, 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, 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.

Special Flight Permits

(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.

Incorporation by Reference

(e) The modification shall be done in accordance with Air

Cruisers Company Service Bulletin 757-105-25-51, dated January 29,

1999. 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 Air Cruisers Company, Technical

Publications Department, P.O. Box 180, Belmar, New Jersey 07719-

0180. 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 January 4, 2000.

Issued in Renton, Washington, on November 18, 1999.

D.L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 99-30628 Filed 11-29-99; 8:45 am]

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