[Federal Register Volume 66, Number 142 (Tuesday, July 24, 2001)]
[Rules and Regulations]
[Pages 38361-38365]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-18137]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-159-AD; Amendment 39-12335; AD 2001-15-01]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 727, 737, 757-200, 757-
200CB, and 757-300 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 727, 737, 757-200, 757-200CB, and 
757-300 series airplanes. This AD requires modification of the latch 
assembly of the escape slides. For certain airplanes, this AD also 
requires installation of a cover assembly on the trigger housing of the 
inflation cylinder on the escape slides. This action is necessary to 
prevent failure of an escape slide to deploy or inflate correctly, 
which could result in the slide being unusable during an emergency 
evacuation and consequent injury to passengers or airplane crewmembers. 
This action is intended to address the identified unsafe condition.

DATES: Effective August 28, 2001.
    The incorporation by reference of certain publications listed in 
the

[[Page 38362]]

regulations is approved by the Director of the Federal Register as of 
August 28, 2001.

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: Keith Ladderud, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, 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 727, 737, 
757-200, 757-200CB, and 757-300 series airplanes was published in the 
Federal Register on February 15, 2001 (66 FR 10384). That action 
proposed to require modification of the latch assembly of the escape 
slides. For certain airplanes, that action also proposed to require 
installation of a cover assembly on the trigger housing of the 
inflation cylinder on the escape slides.

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 Proposed Rule

    One commenter supports the proposed rule.

Identify Additional Affected Airplane Model

    One commenter requests that the FAA revise the proposed rule to 
identify an additional affected airplane model. The commenter states 
that Boeing Model 737-200C airplanes are included in the effectivity 
listing of Boeing Service Bulletin 737-25-1405, dated May 25, 2000, but 
points out that these airplanes were not identified in the proposed 
rule with Model 737-100, -200, -300, -400, and -500 series airplanes.
    The FAA concurs with the commenter's request. Though the FAA 
inadvertently failed to refer to Model 737-200C series airplanes 
separately from Model 737-200 series airplanes in the proposed rule, 
these airplanes are affected by this AD. Therefore, the ``Cost Impact'' 
section, the applicability statement, and Table 1 of this final rule 
have been revised to specifically identify Model 737-200C series 
airplanes along with the other airplane models affected by this AD.

Allow Installation of Unmodified Slide Latch

    One commenter requests that the FAA remove paragraph (b) from the 
proposed AD. (That paragraph, the ``Spares'' paragraph, would prohibit 
installation of certain escape slide assemblies or escape latch 
assemblies after the effective date of this AD.) The commenter states 
that an operator may replace an escape slide on an airplane at any time 
due to a maintenance discrepancy or the slide reaching its overhaul 
threshold. The commenter notes that, on certain fleets, the slide latch 
is part of the complete escape slide assembly; therefore, the latch is 
replaced when a new slide is installed. The commenter states that, by 
not allowing the installation of a non-modified latch prior to the 
compliance time required by the proposed AD, the operator's entire 
spares inventory of escape slides would have to be modified according 
to the proposed AD before the AD becomes effective.
    The FAA concurs with the commenter's request. Operators must comply 
with the requirements of this AD by the specified compliance time. If 
an operator must install a slide, it is their responsibility to ensure 
that all affected parts of that slide conform to the requirements of 
this AD by the compliance deadline. Accordingly, paragraph (b) of the 
proposed rule has not been included in this final rule. (Operators 
should note, however, that once an airplane has been modified according 
to this AD, the airplane cannot be modified in any way that negates 
accomplishment of the actions in this AD--i.e., a modified latch 
assembly cannot be replaced with an unmodified assembly.)

Consider Impact of Previously Issued AD

    One commenter states that the FAA did not adequately consider AD 
90-12-11 R1, amendment 39-6683, when it proposed this AD. The commenter 
points out that AD 90-12-11 R1 requires repetitive inspections of all 
Boeing Model 727, 737, and 757 series airplanes with escape slides 
having release cables installed. Escape slides with such release cables 
installed do not have the split ring assembly that the proposed AD 
would require to be replaced on certain airplanes. The commenter 
further notes that Boeing has issued certain service bulletins that 
provide instructions for replacing release cables on escape slides with 
release chains, which eliminates the need for the inspections required 
by AD 90-12-11 R1. The commenter states that it operates some airplanes 
that have not been modified according to these service bulletins, so 
the airplanes are still equipped with escape slides with release cables 
(and without the split ring assembly). The commenter asks whether the 
FAA intends to require the installation of escape slides with release 
chains on all subject airplanes as part of this AD, or if escape slides 
with release cables are still considered to be acceptable, provided 
that the airplanes continue to be repetitively inspected according to 
AD 90-12-11 R1.
    The FAA concurs that clarification is necessary with regard to the 
requirements of AD 90-12-11 R1. The modification of the escape slide 
latch assembly required by this AD involves two actions for certain 
airplanes. The first action involves replacement of existing spring 
pins with new spring pins. While AD 90-12-11 R1 requires repetitive 
inspections of the slide release latch assembly for frayed or broken 
cables, that AD does not require inspections for corrosion of the 
spring pins because the spring pins cannot be properly inspected for 
corrosion. Therefore, the replacement of the existing spring pins with 
new spring pins is necessary for all airplanes subject to this AD. The 
second action that is part of the modification involves replacement of 
the existing split ring which attaches the chain assembly to the latch 
block assembly, with a clevis. In response to the commenter's concern, 
the FAA finds that an operator of an airplane subject to the 
requirement to replace the split ring with a clevis may not be required 
to do this replacement if the airplane is equipped with a release cable 
instead of a release chain. Operators of airplanes equipped with a 
release cable instead of a release chain may request approval of an 
alternative method of compliance under the provisions of paragraph (b) 
of this AD, as long as the airplane is receiving the repetitive 
inspections required by AD 90-12-11 R1. Operators should note that Note 
1 of this AD applies to airplanes modified, altered, or repaired in the 
area subject to the requirements of this AD. Due to the fact that Note 
1 already addresses this circumstance, no change to this AD is 
necessary in this regard.

[[Page 38363]]

Extend Compliance Time for Certain Airplanes

    One commenter requests that the FAA extend the compliance time from 
18 months to 36 months for the actions required by this AD on Boeing 
Model 737-600, -700, and -800 series airplanes. The commenter notes 
that, as the FAA stated in the proposed rule, the 18-month compliance 
time for these airplanes is based on the degree of urgency associated 
with installation of a cover assembly on the trigger housing of the 
inflation cylinder on the escape slides, as specified in Boeing Special 
Attention Service Bulletin 737-25-1403, dated May 4, 2000. The 
commenter states that some operators have already accomplished that 
service bulletin, and other airplanes are not subject to the actions in 
that service bulletin because they are equipped with different escape 
slides. The commenter states, for these airplanes, the compliance time 
for accomplishment of the modification of the slide latch assembly 
described in Boeing Service Bulletin 737-25-1404, dated May 25, 2000, 
should be 36 months.
    The FAA does not concur with the commenter's request to extend the 
compliance time. The commenter notes that, for certain airplanes as 
listed in Boeing Service Bulletin 737-25-1404, that service bulletin 
specifies accomplishment of Boeing Special Attention Service Bulletin 
737-25-1403 as an integral part of the other actions in that service 
bulletin. For this reason, the FAA finds that it is necessary to 
mandate accomplishment of Boeing Service Bulletin 737-25-1404 within 18 
months after the effective date of this AD, as proposed. However, the 
FAA notes that operators of airplanes on which Boeing Special Attention 
Service Bulletin 737-25-1403 has been accomplished may request approval 
of an alternative method of compliance or adjustment of the compliance 
time under the provisions of paragraph (b) of this AD. No change to the 
final rule is necessary in this regard.

Allow Use of Solid Spring Pin

    The modification of the escape slide latch assembly for all 
airplanes subject to this AD involves replacement of existing spring 
pins with new spring pins made from corrosion-resistant material. One 
commenter requests that the FAA approve the use of a new, solid spring 
pin with both ends staked as an alternative to the spring pin of 
hollow-roll design that is specified in the service bulletins. The 
commenter states that the spring pin specified in the service bulletins 
may allow for collection of water in the pin which could lead to 
corrosion. The commenter states that a solid pin will provide the 
corrosion prevention needed to ensure the integrity of the pin and 
operation of the slide latch and will provide a level of safety 
equivalent to that provided by the pin specified in the service 
bulletins.
    The FAA does not concur with the commenter's request to allow use 
of a solid pin with staked ends. The FAA notes that the latch assembly 
housing is a forged part and is made of hard, corrosion-resistant 
steel. If solid spring pins are installed and staked at both ends, it 
may be possible for these pins to bend or be insufficiently staked, 
which could result in an unacceptable latch assembly. Therefore, the 
FAA finds that the spring pins must be replaced with the new pins 
specified in the applicable service bulletin. No change to the final 
rule is necessary in this regard.

Require Replacement of Latch Assemblies With New Assemblies

    One commenter states that the escape slide latch assemblies that 
are subject to this AD should not be reworked as allowed by the 
proposed rule, but, rather, should be replaced with new latch 
assemblies. The commenter is concerned about modifying the existing 
latches due to the critical nature of these latches.
    The FAA does not concur with the commenter's request. The FAA does 
not consider the modifications in the referenced service bulletins 
technically challenging, and expects that operators should be able to 
accomplish such modifications. No change to the final rule is necessary 
in this regard.

Adjust Cost Impact Information

    One commenter states that, because the proposed AD results from a 
design defect, replacement parts for the modification of the escape 
slide latch assembly should be supplied at no cost to the operators. 
The commenter makes no specific request for a change to the proposed 
rule. The FAA acknowledges this comment, but the FAA cannot mandate 
which party should bear the cost of replacement parts. This issue must 
be negotiated between the operator and the manufacturer. 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 5,759 Model 727, 737, 757-200, 757-200CB, 
and 757-300 airplanes of the affected design in the worldwide fleet. 
The FAA estimates that 2,906 airplanes of U.S. registry will be 
affected by this AD. The following table shows the estimated cost 
impact for airplanes affected by this AD. ``Action 1'' is the 
modification of the escape slide latch assembly, and ``Action 2'' is 
the installation of a cover assembly on the trigger housing of the 
inflation cylinder on the escape slide. The average labor rate is $60 
per work hour. The estimated cost impact is as follows:

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                                                U.S.-      Work hours    Parts cost     Cost per       Maximum
        Models/series            Action      registered   per airplane   (estimated     airplane     fleet cost
                                              airplanes    (estimated)    maximum)     (estimated)   (estimated)
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727.........................             1           955             2        $1,068        $1,188    $1,134,540
737-100, -200, -200C, -300, -            1         1,156             2         1,192         1,312     1,516,672
 400, -500..................
737-600, -700, -800.........             1           277             2         1,424         1,544       427,688
737-600, -700, -800.........             2           277             4          Free           240        66,480
757-200, -200CB, -300.......             1           518             3         1,602         1,782       923,076
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    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. 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

[[Page 38364]]

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 adopted herein will 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 final rule does not have federalism 
implications under Executive Order 13132.
    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:

2001-15-01  Boeing: Amendment 39-12335. Docket 2000-NM-159-AD.

    Applicability: The following airplanes, certificated in any 
category:

------------------------------------------------------------------------
                                                      Service bulletin
             Model                 As listed in             date
------------------------------------------------------------------------
727-100 and 727-200 series....  Boeing Service     May 25, 2000.
                                 Bulletin 727-25-
                                 0294.
737-100, -200, -200C, -300, -   Boeing Service     May 25, 2000.
 400, and -500 series.           Bulletin 737-25-
                                 1405.
737-600, -700, and -800 series  Boeing Special     May 4, 2000.
                                 Attention
                                 Service Bulletin
                                 737-25-1403.
737-600, -700, and -800 series  Boeing Service     May 25, 2000.
                                 Bulletin 737-25-
                                 1404.
757-200 and -200CB series.....  Boeing Service     May 25, 2000.
                                 Bulletin 757-25-
                                 0217.
757-300 series................  Boeing Service     May 25, 2000.
                                 Bulletin 757-25-
                                 0218.
------------------------------------------------------------------------


    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 failure of an escape slide to deploy or inflate 
correctly, which could result in the slide being unusable during an 
emergency evacuation and consequent injury to passengers or airplane 
crewmembers, accomplish the following:

Modification

    (a) At the schedule specified in the following table, do the 
actions in the ``Do these actions'' column, per the service bulletin 
specified in the ``As listed in'' column:

                                           Table 1.--Required Actions
----------------------------------------------------------------------------------------------------------------
            For model                As listed in            Dated         Do these actions      No later than
----------------------------------------------------------------------------------------------------------------
727-100 and 727-200 series......  Boeing Service      May 25, 2000......  Modify the escape   36 months after
                                   Bulletin 727-25-                        slide latch         the effective
                                   0294.                                   assembly.           date of this AD.
737-100, -200, -200C, -300, -     Boeing Service      May 25, 2000......  Modify the escape   36 months after
 400, and -500 series.             Bulletin 737-25-                        slide latch         the effective
                                   1405.                                   assembly.           date of this AD.
737-600, -700, and -800 series..  Boeing Special      May 4, 2000.......  Install a cover     18 months after
                                   Attention Service                       assembly on the     the effective
                                   Bulletin 737-25-                        trigger housing     date of this AD.
                                   1403.                                   of the inflation
                                                                           cylinder on the
                                                                           escape slides.
737-600, -700, and -800 series..  Boeing Service      May 25, 2000......  Modify the escape   18 months after
                                   Bulletin 737-25-                        slide latch         the effective
                                   1404.                                   assembly.           date of this AD.
757-200 and -200CB series.......  Boeing Service      May 25, 2000......  Modify the escape   36 months after
                                   Bulletin 757-25-                        slide latch         the effective
                                   0217.                                   assembly.           date of this AD.
757-300 series..................  Boeing Service      May 25, 2000......  Modify the escape   36 months after
                                   Bulletin 757-25-                        slide latch         the effective
                                   0218.                                   assembly.           date of this AD.
----------------------------------------------------------------------------------------------------------------

Alternative Methods of Compliance

    (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. 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

    (c) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199

[[Page 38365]]

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

    (d) The actions shall be done in accordance with Boeing Service 
Bulletin 727-25-0294, dated May 25, 2000; Boeing Special Attention 
Service Bulletin 737-25-1403, dated May 4, 2000; Boeing Service 
Bulletin 737-25-1404, dated May 25, 2000; Boeing Service Bulletin 
737-25-1405, dated May 25, 2000; Boeing Service Bulletin 757-25-
0217, dated May 25, 2000; and Boeing Service Bulletin 757-25-0218, 
dated May 25, 2000; as applicable. 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.

Effective Date

    (e) This amendment becomes effective on August 28, 2001.

    Issued in Renton, Washington, on July 13, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-18137 Filed 7-23-01; 8:45 am]
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