Airworthiness Directives; Boeing Model 737-100, -200, -300, -400, and -500 Series Airplanes

[Federal Register Volume 64, Number 5 (Friday, January 8, 1999)]
[Rules and Regulations]
[Pages 1112-1114]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-185]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-238-AD; Amendment 39-10981; AD 99-01-16]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-100, -200, -300, -400, 
and -500 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 737-100, -200, -300, -400, and -500 
series airplanes, that requires installation of a placard that warns 
the cabin crew not to put the selector valve for the forward lavatory 
water supply in the ``DRAIN'' position during flight. This amendment 
also requires installation of an isolation valve in the drain line 
downstream of the selector valve, which would terminate the requirement 
for the placard installation. This amendment is prompted by reports of 
damage to the horizontal stabilizer, and engine flameout caused by ice 
formed from water drained inadvertently through a mispositioned 
selector valve. The actions specified by this AD are intended to 
prevent damage to the engines, airframe, or horizontal stabilizer, and/
or to prevent a hazard to persons or property on the ground, as a 
result of ice that could dislodge from the airplane.

DATES: Effective February 12, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of February 12, 1999.

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 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.

FOR FURTHER INFORMATION CONTACT: Don Eiford, 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) 227-2788; 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 737-100, -200, -
300, -400, and -500 series airplanes was published in the Federal 
Register on November 13, 1997 (62 FR 60810). That action proposed to 
require installation of a placard that warns the cabin crew not to put 
the selector valve for the forward lavatory water supply in the 
``DRAIN'' position during flight. That action also proposed to require 
installation of an isolation valve in the drain line downstream of the 
selector valve.

Consideration of Comments Received

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Request To Delay Issuance of AD Pending Release of Service 
Information

    Several commenters request delay of the issuance of the AD pending 
the release of appropriate service information that provides technical 
details for installation of the isolation valve. The commenters state 
that, without such service information, they are unable to provide 
meaningful comments regarding the technical content of the proposed AD.
    The FAA partially concurs with the commenter's request. The FAA 
recognizes that a service bulletin would provide technical details and 
procedures for accomplishing the actions proposed by the notice of 
proposed rulemaking (NPRM). However, the issue subject to public 
comment was the general requirement for the placard and valve 
installations. Further, because the valve installation is not expected 
to be technically complicated or difficult to accomplish, the FAA does 
not anticipate receiving any comments addressing the technical aspects 
of the valve installation. In light of this information, the FAA has 
determined that it is unnecessary to delay issuance of the final rule.

Request To Revise Applicability

    One commenter states its understanding of the applicability as

[[Page 1113]]

being limited to those models on which forward lavatories are 
installed.
    The FAA infers that the commenter is requesting that the FAA revise 
the applicability to include that limitation. The FAA concurs with the 
commenter's request, having determined that an affected airplane 
without a forward lavatory installed would not be subject to the 
identified unsafe condition. The applicability of the final rule has 
been revised accordingly.

Request To Consider Valve Installation as Terminating Action

    One commenter requests that the proposed AD be revised to require 
installation initially of either the placard or the valve. That 
commenter considers the valve installation as the primary solution to 
address the identified unsafe condition; therefore, valve installation 
(if accomplished within the compliance time required for the placard 
installation) would preclude the need for the placard installation. 
That commenter suggests some airlines may choose to incorporate the 
valves within the 6-month window and forgo the placard installation. As 
further justification for its request, the commenter adds that 
production airplanes now include the isolation valve but not the 
placard.
    The FAA concurs with the request to require installation initially 
of either the placard or the valve. The FAA's intent behind 
installation of a placard, as proposed by the NPRM, was to provide an 
expeditious means to achieve an acceptable level of safety pending 
installation of the isolation valve. However, the FAA agrees that the 
isolation valve is considered the primary design solution to the 
identified unsafe condition. Therefore, the placard would not be needed 
if the valve is installed within the 6-month compliance time required 
to install the placard. The final rule has been revised to specify 
this, and to indicate that installation of the valve terminates the 
requirement for installation of the placard.

Request To Remove Requirement for Valve Installation

    One commenter reports that it has not experienced the problem 
addressed in the proposed AD. The commenter states that the proposed 
requirement to install an isolation valve in the drain line is 
unnecessary, and installation of a placard should be sufficient to 
address the unsafe condition.
    The FAA infers that the commenter is requesting removal of the 
requirement to install the valve. The FAA does not concur. The FAA has 
determined that long-term continued operational safety will be better 
assured by design changes to remove the source of the problem, rather 
than by reliance on the cabin crew following additional procedures. 
This determination, coupled with a better understanding of the human 
factors associated with following such procedures, has led the FAA to 
consider placing less emphasis on the use of informational placards and 
more emphasis on design improvements. The valve installation 
requirement is in consonance with these conditions. No change to the 
final rule in this regard is necessary.

Concern Regarding AD Effectiveness

    One commenter generally supports the proposal, but urges the FAA to 
continue to monitor occurrences of airframe damage and engine flameout 
due to inadvertent or erroneous drain valve activation in flight. The 
commenter states that the proposed corrective action would reduce but 
not eliminate the possibility of this unsafe condition, and urges the 
FAA to determine if a more active means of preventing the unsafe 
condition would be appropriate.
    The FAA acknowledges the commenter's concern and will continue to 
monitor such occurrences of airframe damage and engine flameout. The 
FAA may consider further rulemaking activity if additional corrective 
actions are deemed necessary.

Actions Since Issuance of NPRM

    Since the issuance of the NPRM, the FAA has reviewed and approved 
Boeing Service Bulletin 737-38-1043, dated January 8, 1998, which 
provides procedures for the installation of the placard. Paragraph (a) 
of the final rule has been revised to incorporate the service bulletin 
as the appropriate source of service information for the placard 
installation. In addition, Figure 1 of the NPRM (which depicts the 
placard) has been removed from the final rule because an appropriate 
figure is provided in the service bulletin.

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 described 
previously. 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 2,830 airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 1,037 airplanes of U.S. 
registry will be affected by this AD.
    It will take approximately 1 work hour per airplane to accomplish 
the required placard installation, at an average labor rate of $60 per 
work hour. Based on these figures, the cost impact of this installation 
required by this AD on U.S. operators is estimated to be $62,220, or 
$60 per airplane.
    It will take approximately 6 work hours per airplane to accomplish 
the required installation of an isolation valve, at an average labor 
rate of $60 per work hour. Required parts will cost approximately $300 
per airplane. Based on these figures, the cost impact of this 
installation required by this AD on U.S. operators is estimated to be 
$684,420, or $660 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 section (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 obtain 
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.

[[Page 1114]]

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:

99-01-16 Boeing: Amendment 39-10981. Docket 97-NM-238-AD.

    Applicability: Model 737-100, -200, -300, -400, and -500 series 
airplanes; having forward lavatories installed; 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 (d) 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 damage to the engines, airframe, or horizontal 
stabilizer, and/or to prevent a hazard to persons or property on the 
ground, accomplish the following:
    (a) Except as provided by paragraph (c) of this AD: Within 6 
months after the effective date of this AD, install a placard on the 
door beneath the forward lavatory sink, that warns the cabin crew 
not to put the selector valve for the forward lavatory water supply 
in the ``DRAIN'' position during flight. The installation shall be 
accomplished in accordance with Boeing Service Bulletin 737-38-1043, 
dated January 8, 1998.
    (b) Within 36 months after the effective date of this AD, 
install an isolation valve in the drain line downstream of the 
selector valve for the forward lavatory water supply, in accordance 
with a method approved by the Manager, Seattle Aircraft 
Certification Office (ACO), FAA, Transport Airplane Directorate. 
Once the valve is installed, the placard described in paragraph (a) 
of this AD may be removed.
    (c) For airplanes on which the valve installation required by 
paragraph (b) of this AD is accomplished within the compliance time 
specified in paragraph (a) of this AD, the placard installation 
required by paragraph (a) is not required.
    (d) 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 ACO. 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.

    (e) 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.
    (f) The placard installation shall be done in accordance with 
Boeing Service Bulletin 737-38-1043, dated January 8, 1998. 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.
    (g) This amendment becomes effective on February 12, 1999.

    Issued in Renton, Washington, on December 30, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-185 Filed 1-7-99; 8:45 am]
BILLING CODE 4910-13-U

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