[Federal Register Volume 69, Number 58 (Thursday, March 25, 2004)]
[Rules and Regulations]
[Pages 15238-15248]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-6677]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-111-AD; Amendment 39-13544; AD 2004-06-18]
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 supersedes an existing airworthiness directive 
(AD), applicable to certain Boeing Model 737-300 and -400 series 
airplanes, that currently requires either repetitive leak checks on the 
forward lavatory service system and repair, as necessary, or draining 
of the system and placarding the lavatory inoperative. This amendment 
also requires periodic changing of the seals of certain lavatory drain 
systems; replacing ``donut valves'' with other FAA-approved valves; 
revising certain leak test intervals; and revising the pressurization 
and fluid level requirements for testing. The actions specified by this 
AD are intended to prevent damage to engines, airframes, and property 
on the ground that is associated with the problems of ``blue ice'' that 
forms from leaking lavatory drain systems on transport category 
airplanes and subsequently dislodges from the airplane fuselage.

DATES: Effective April 29, 2004.

ADDRESSES: Information pertaining to this amendment may be examined at 
the Federal Aviation Administration (FAA), Transport Airplane 
Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Don Eiford, Aerospace Engineer, Cabin 
Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington; telephone (425) 917-6465; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 89-11-03, 
amendment 39-6223 (54 FR 21933, May 22, 1989), which is applicable to 
certain Boeing Model 737-300 and -400 series airplanes, was published 
as a supplemental notice of proposed rulemaking (NPRM) in the Federal 
Register on November 26, 1997 (62 FR 62708). That action proposed to 
continue to require either repetitive leak checks on the forward 
lavatory service system and repair, as necessary, or draining of the 
system and placarding the lavatory inoperative. In addition, that 
action proposed to add a requirement to perform leak checks of other 
lavatory drain systems; require the installation of a cap or vacuum 
break on the flush/fill line; and require either a periodic replacement 
of the seal for the cap and tank anti-siphon valve or periodic 
maintenance of the vacuum break in the flush/fill line. Further, that 
action proposed to require a periodic changing of the seals of certain 
lavatory drain systems; and replacing ``donut valves'' with other FAA-
approved valves.

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.

Comments That Resulted in a Change To the Final Rule

Requests To Extend Leak Test Interval

    One commenter requests that paragraph (a)(4) of the supplemental 
NPRM be revised to extend the leak test intervals of certain service 
panel drain valves (also known as and referred to in the supplemental 
NPRM as waste drain valves) from 1,000 flight hours to 2,000 flight 
hours. The commenter also requests that Table 1 of paragraph (a) of the 
supplemental NPRM be updated to reflect the appropriate valves approved 
for the 1,000-flight hour interval. In addition, the commenter requests 
that paragraph (a)(5) of the supplemental NPRM be revised to extend the 
leak test intervals from 600 flight hours to 1,000 flight hours. The 
commenter advises that more than 7,000 Shaw valves have accumulated in 
excess of 50 million flight hours during the past 10 years. The 
commenter states that it is aware of less than five blue ice events 
that could have been attributed to a Shaw Aero service panel valve and 
suggests that this is ample evidence to support the extensions of the 
leak test intervals. The commenter further states that service 
experience clearly indicates that the main problems regarding blue ice 
occur

[[Page 15239]]

after a period of two years of residue build-up on the sealing surfaces 
of the valve design. Therefore, the commenter concludes that the 
performance of the Shaw valves in real life maintenance environments 
will, if approved for an interval of 2,000 flight hours for the leak 
test, continue to operate with no blue ice events.
    Another commenter requests that the improved Shaw valves specified 
in Table 1 of paragraph (a) of the supplemental NPRM be approved for 
the 2,000 flight hour interval that is specified in paragraph (b) of 
the supplemental NPRM. The commenter states that the improved valves 
specified in Table 1 of paragraph (a) of the supplemental NPRM, coupled 
with the incorporation of the maintenance program specified in 
paragraph (b) of the supplemental NPRM, justify increasing the leak 
test intervals.
    The FAA agrees that the interval for the leak test of the waste 
drain valves specified in Table 1 of paragraph (a) of the supplemental 
NPRM should be extended. Since the issuance of the supplemental NPRM, 
requests for alternative methods of compliance (AMOCs) have been 
approved to extend the leak test interval to 4,000 flight hours for 
certain valves. We have determined that, if those valves are maintained 
properly, the valves are capable of leak-free operation. To simplify 
and clarify the requirements of this AD, we have consolidated the leak 
test intervals for certain valves specified in the supplemental NPRM 
for -4,500, -2,000, and -1,000 flight hour intervals into one group 
with a leak test interval of 4,500 flight hours. Therefore, we have 
revised this final rule to specify that the valves listed in Table 1 of 
this AD are approved for a leak test interval of 4,500 flight hours. 
For certain other valves, we have consolidated the leak test interval 
to 1,000 flight hours. Consequently, after the removal of ``donut'' 
type valves as required by this AD, there will be only two leak test 
intervals specified in the AD. To accommodate this change in the final 
rule, we have consolidated the requirements of paragraphs (a)(2), 
(a)(3), and (a)(4) of the supplemental NPRM into paragraph (a)(2) of 
this AD. We consider that the requirement of this AD to repair any 
leaking valves before further flight to be an additional safety factor 
in this determination.

Request To Add a Panel Ball Valve With a 48-Month Seal Replacement 
Interval

    Two commenters request that the interval for the leak test for 
Kaiser Electroprecision panel ball valve, part number (P/N) 2651-357, 
be extended to 2,000 flight hours. Both commenters request that the 
seal replacement interval be every 48 months. The commenters explain 
that ample testing with airlines has been accomplished to justify the 
2,000 flight hour interval.
    We agree with the commenters' request. Since the issuance of the 
supplemental NPRM, additional flight data has been submitted to the FAA 
justifying an extension of the leak check interval. Additionally, the 
valve manufacturer has recommended that the seal change interval be 
revised to every 48 months. We have revised paragraphs (a) and (d) of 
the final rule to reflect these changes.

Requests Regarding Use of Certain Leak Test Tools

    Three commenters request that use of a vacuum leak test tool be 
approved for performing the requirements of paragraph (b)(3)(ii)(A) of 
the supplemental NPRM, just as it is specified in paragraph 
(a)(8)(ii)(A) of the supplemental NPRM. The commenters note that use of 
a vacuum leak test tool does not require the airplane to be 
pressurized, and is, therefore, valid for performing the requirements 
of both paragraphs.
    We agree with the commenters' request. We have redesignated 
paragraph (b) of the supplemental NPRM to paragraph (d) of the final 
rule and revised it from, ``Pressurize the airplane to 3 PSID * * *'' 
to ``Apply 3 PSID across the valve in the same direction as occurs in 
flight.''
    Another commenter requests the FAA to specify that it is 
unnecessary to completely cover the upstream end of the valve being 
tested with fluid when a vacuum leak test tool is used to test the 
inner seal of the service panel valves. The commenter notes that 
leakage will be detected by a loss of applied vacuum, not by fluid 
leaking past the inner seal.
    We agree and have added new paragraphs (b) and (c) of this AD that 
specify procedures to perform vacuum leak tests.

Requests To Provide an Additional Option for Paragraph (d) of the 
Supplemental NPRM

    Several commenters request that installation of an FAA-approved 
liquid level sensor and motorized shut-off valve (also known as and 
specified as an automatic shut-off valve in the supplemental NPRM) be 
accepted as another option for compliance with the requirements of 
paragraph (d) of the supplemental NPRM. That paragraph specifies 
installation of an FAA-approved lever/lock cap, vacuum break, or flush/
fill ball valve for all lavatories. Additionally, the commenters 
request that this system also be provided in paragraphs (a)(8) and 
(b)(3) of the supplemental NPRM. One commenter points out that the 
automatic shut-off valve system is similar to other systems currently 
installed in another airplane model, and it has proven effective in 
preventing ``blue ice'' incidents.
    We agree with the commenters' request and have revised those 
paragraphs of the final rule to add the automatic shut-off valve as an 
additional method of compliance. Also, we have redesignated paragraph 
(d) of the supplemental NPRM as paragraph (f) of the final rule, and 
paragraphs (a)(8) and (b)(3) of the supplemental NPRM as paragraphs 
(a)(5)(iv) and (d)(3)(iv) of the final rule.

Request To Specify Terminating Action

    One commenter requests that the actions required by the 
supplemental NPRM and incorporation of an FAA-approved maintenance 
program be considered as terminating action for the requirements of the 
supplemental NPRM. The commenter states that the proposed actions, such 
as donut valve removal, seal replacement, and rinse system upgrade, 
will reduce the incidence of ``blue ice'' significantly, and in 
conjunction with the FAA-approved maintenance program, justify 
providing accomplishment of those actions as terminating action.
    We agree with the commenter's request. A review of reports 
indicates that, since the issuance of several blue ice ADs, the number 
of reported events of blue ice has decreased markedly. We consider the 
decrease as an indication that the existing blue ice ADs are effective. 
Therefore, we have revised paragraph (d) of the final rule to allow 
terminating action by incorporation of the requirements of paragraphs 
(d), (f), and (g) of the AD into the operator's FAA-approved 
maintenance program.

Request To Extend Intervals for Seal Replacement

    One commenter requests that paragraphs (a)(1) and (b)(1) of the 
supplemental NPRM be revised to provide that, for waste drain systems 
that incorporate more than one type of valve, the seal replacement 
interval of all affected valves in the system would be that of the 
valve with the longest seal replacement interval. For example, if an 
in-line drain valve were installed with a service panel valve, 
replacement of the service panel valve seal would coincide with 
replacement of the in-line drain valve seal. The commenter suggests 
that it be specified that the secondary valve would not be a means of 
continuing

[[Page 15240]]

operations if the seal of the valve with the longest replacement 
interval were malfunctioning.
    We partially agree with the commenter. We have revised paragraphs 
(a)(1) and (d)(1) of the AD to permit extension of the interval for 
replacement of the seals. However, we do not consider it necessary to 
specify that the secondary valve would not be a means of continuing 
operations if the seal of the valve with the longest replacement 
interval is malfunctioning, since the final rule requires any worn or 
damaged seal or any seal leakage to be repaired before further flight.

Request To Revise Paragraph (b) To Clarify Leak Test Interval

    One commenter requests that certain language used in paragraph (a) 
of the supplemental NPRM be added to paragraph (b) of the supplemental 
NPRM. The language states, ``If the waste drain system incorporates 
more than one type of valve, only one of the waste drain system leak 
test procedures (the one that applies to the equipment with the longest 
leak test interval) must be conducted at each service panel location.''
    We agree that clarification is needed and have revised the final 
rule accordingly. Paragraph (b) of the supplemental NPRM also has been 
redesignated as paragraph (d) of the final rule.

Request To Add Appropriate Leak Tests for Auxiliary Waste Tanks

    One commenter states that the flush/fill line valve tests specified 
in paragraphs (a) and (b) of the supplemental NPRM cannot be 
accomplished as specified for airplanes that have auxiliary waste tanks 
installed. The commenter explains that auxiliary waste tanks cannot be 
half-filled because the bowl is installed only on the primary waste 
tank. Additionally, the primary waste tank cannot be tested by this 
procedure without filling the auxiliary tank, because the standpipe 
installation in the primary tank precludes filling the bowl half-full. 
Therefore, the commenter requests that an appropriate leak test be 
specified for those airplanes with auxiliary waste tanks installed. The 
commenter did not suggest any specific leak test.
    We agree with the commenter's request. Since using a vacuum test 
does not require filling the tanks with fluid, we have determined that 
such use of a vacuum test in accordance with applicable airplane and 
component maintenance manuals will provide an acceptable method to 
comply with the leak test requirements for airplanes with auxiliary 
waste tanks installed. We have clarified paragraphs (a)(5) and (d)(3) 
of the final rule to specify that vacuum test equipment (rigs) may be 
used for those airplanes for the flush/fill line leak tests.

Request To Allow Certain Leak Test Extensions

    One commenter states that, although paragraph (c) of the 
supplemental NPRM provides for revision of the leak test intervals 
required by paragraph (b) of the supplemental NPRM, no similar 
provision is made for operators who comply with the requirements of 
paragraph (a) of the supplemental NPRM. The commenter explains that it 
is implementing a maintenance program that complies with the 
requirements of paragraph (a) of the supplemental NPRM for certain 
airplanes in its fleet, and that it complies with the requirements of 
paragraph (b) of the supplemental NPRM for certain other airplanes in 
its fleet. The commenter requests that paragraph (c) of the 
supplemental NPRM be revised to permit extension of the leak test 
intervals for airplanes that are in compliance with either paragraph 
(a) or (b) of the supplemental NPRM.
    We agree. The provision to extend the leak test intervals provided 
in paragraph (c) of the supplemental NPRM has been revised accordingly. 
Paragraph (c) of the supplemental NPRM has also been redesignated as 
paragraph (e) in the final rule.

Request To Clarify Use of ``Dump Valve''

    One commenter requests that the FAA revise the term ``dump valve'' 
as used in the supplemental NPRM to read ``toilet tank dump valve.'' We 
agree with the commenter's request and have changed the final rule 
accordingly.

Request To Specify ``FAA-Approved Vacuum Breaks''

    One commenter requests that, rather than requiring the use of two 
particular vacuum breaks as specified in paragraph (a) of the 
supplemental NPRM, the FAA require the use of any FAA-approved vacuum 
breaks. We agree with the commenter's request and have changed the 
final rule accordingly.

Request To Revise a Part Number for the Vacuum Breaker Check Valve

    One operator requests that reference to the P/N series for the Shaw 
vacuum breaker check valves by changed from ``301-0009-01'' to ``309-
0009.'' We agree with the commenter's request and have corrected the 
references to those P/Ns in the final ru;e accordingly.

Comments Received That Did Not Result in a Change to the Final Rule

Request To Approve Terminating Action

    One commenter requests that a certain in-line drain valve be 
approved as a terminating action for the requirements of paragraph (b) 
of the supplemental NPRM. The commenter states that it is not aware of 
any reports of leakage on the particular valve.
    We do not agree with the commenter's request. Since in-line drain 
valves may be damaged, fouled, and worn, we have determined that it is 
not appropriate to approve those valves as a terminating action for the 
requirements of paragraph (b) of the supplemental NPRM (redesignated as 
paragraph (d) in the final rule). However, we have also provided for 
terminating action by allowing incorporation of the requirements of 
paragraphs (d), (f), and (g) of the final rule into the operator's FAA-
approved maintenance program.

Request To Revise Replacement Intervals

    One commenter states that the FAA should not extend replacement 
intervals for certain valve seals based on the success of certain other 
in-line ball valve seals. The commenter specifies that the two 
different types of valves are not similar, and therefore, extending the 
replacement intervals should not be approved on that basis.
    We do not agree that certain valve seals should not have the 
replacement interval extended. We did not approve the extension of the 
replacement interval of the seals based on similarity with another type 
of valve. We based that approval on the manufacturer's recommended seal 
change interval and on the successful operating experience with an 
extended interval for the seal change. No change is necessary to the 
final rule in this regard.

Request To Require Both a Vacuum Break Check Valve and a Lever Lock Cap

    Two commenters request that the FAA require both a vacuum break 
check valve and a lever lock cap on the lavatory fill/rinse line. One 
commenter states that a large portion of blue ice leakage propagates 
from the lavatory fill/rinse line and check valve designs are 
inherently vulnerable to this waste system environment. Also, a single 
vacuum breaker check valve provides no positive mechanical means of 
closure as required for all other critical leak path valves with the 
waste system.
    We do not agree with the commenter's request. As we explained in 
the ``Comments Received'' section of the

[[Page 15241]]

supplemental NPRM, we acknowledge that redundant systems generally 
provide a higher level of safety; however, in this case, the vacuum 
breaker provides redundancy to the check valve function. In the case of 
a check valve alone, the lever lock cap provides redundancy to the 
check valve. There are insufficient data to show which combination is 
more reliable. No change is necessary to the final rule in this regard.

Request To Revise Replacement Intervals of Certain Seals

    Two commenters request that the seal replacement intervals 
specified in paragraphs (a)(1)(ii) and (b)(1)(ii) of the supplemental 
NPRM be revised from ``Thereafter, repeat the replacement of the seals 
at intervals not to exceed 18 months or 6,000 flight hours, whichever 
occurs later'' to read ``Thereafter, repeat the replacement of the 
seals at intervals not to exceed 18 months.'' One commenter did not 
provide any justification for the requested change. The other commenter 
states that the seal in a ball-type or half-ball type valve (especially 
when used at the service panel) is subjected to significantly greater 
dynamic action than the seal in a flapper-type valve. The distance that 
the ball or half-ball drags across the seal subjects the seal to 
considerably more wear than that experienced by an o-ring seal in a 
flapper-type valve as it moves from a sealed to an unsealed position. 
Also, the plastic seals used in the ball or half-ball type valves are 
much less forgiving and less compressible than elastomer-type seals 
used in flapper-type valves and thus are more susceptible to being 
damaged by foreign objects and allowing leakage. The potential for ice, 
hardened debris, and black tar buildup on the ball at the service panel 
makes the seals much more susceptible to damage as the ball is dragged 
across the seals. The commenter concludes that the location of the 
service panel valve relative to the in-line valve makes damage more 
susceptible to the seals or mating surfaces as a result of service and 
maintenance processes.
    We do not agree with the commenters' request. The proposed 
replacement intervals for those seals specified in the supplemental 
NPRM were based on the manufacturer's recommended seal change interval 
and on successful operational experience with a longer seal change 
interval. We consider that, if leakage does occur before the specified 
replacement interval, the requirement to repair any leaks or placard 
the lavatory inoperative before further flight will ensure that the 
valve does not continue to leak. No change is necessary to the final 
rule in this regard.

Request To Require the Same Proof for Approval

    One commenter requests that other valve suppliers be required to 
complete the same or similar number of flight test hours as the 
PneuDraulics valve before extended leak test intervals are granted, and 
that credit for similarity be disallowed. The commenter states that the 
25,000 flight hours and use of similarity to approve extended leak 
check intervals for valves as proposed in Notes 9 and 11 of the 
supplemental NPRM are inadequate. The commenter states that the FAA 
required it to complete 13 million flight hours over a 3-year period 
before an extension to 4,000 flight hours was considered. The commenter 
asserts that other applicants for extended leak test intervals should 
be required to have a similar service history, and that service history 
should be based upon in-flight experience with the exact design in the 
exact location of use. The commenter states that the FAA cannot act as 
a judge of equality in the marketplace, and that it must maintain its 
role of acting in the best interest of airline passenger safety. The 
commenter recommends that the FAA judge engineering data equally and 
fairly, and that all requests for approval of an extended leak test 
extension be determined by the same set of criteria.
    We do not agree that ``credit'' for similarity should be 
disallowed. We have allowed use of similarity for partial credit in 
lieu of service experience, but a considerable amount of successful 
service history was required before an extended interval was approved. 
In granting such approvals, we primarily consider service history 
obtained by operators using a program to gather data similar to that 
outlined in paragraph (b) of the supplemental NPRM. For instance in the 
case of a certain valve, operators reported approximately 936,000 
flight hours and one leak. In another case, operators reported 
approximately 848,000 flight hours and 2 leaks. In a third case, 
operators reported approximately 480,000 flight hours and no leaks, 
plus similarity to another valve manufactured by the same company. 
These data indicate that any of these valves can be effective in 
service. The requirement to repair any leak or placard the lavatory 
inoperative before further flight is intended to motivate operators to 
select and maintain the most reliable valves in order to avoid leaking. 
No change is necessary to the final rule in this regard.

Request To Reduce Time of the Leak Test

    One commenter requests that the duration of the five-minute leak 
test be reduced to one minute for the leak tests that are performed 
with a vacuum leak check tool. The commenter states that any leak path 
will be readily detected within one minute when a three pounds per 
square inch differential pressure is generated. If the pressure gauge 
remains stationary, the inner seal is leak-tight.
    We do not agree with the commenter's request. The commenter did not 
provide any data to substantiate that a one-minute leak test is as 
sensitive to low leakage rates as a five-minute leak test. No change is 
necessary to the final rule in this regard. However, under the 
provisions of paragraph (h) of the final rule, the FAA may approve 
requests for alternative method of compliance (AMOC) if data are 
submitted to substantiate that such an AMOC would provide an acceptable 
level of safety.

Request To Revise the Economic Impact Section

    One commenter requests that the FAA add information to the Economic 
Impact section to advise operators that the leak check tool (the hand-
held vacuum pump) provides a more economic method of performing the 
leak test. The commenter states that without the leak check tool, the 
engine or auxiliary power unit (APU) must be started and the leak test 
will take four work hours for each lavatory drain valve. The commenter 
points out that, with the leak check tool, there is no need to power up 
the airplane and the leak test takes only five or 10 minutes to perform 
for each lavatory drain.
    We do agree that it is necessary to add the additional information 
concerning the costs of performing a leak test with the leak check 
tool. As explained in the Economic Impact section of the supplemental 
NPRM and in this final rule, the costs discussed are estimates based on 
the fact that certain airplanes may be required to be leak tested as 
many as 15 times each year, while certain other valve configurations 
may be required to be leak tested as few as three times each year. 
Additionally, some airplanes that have various combinations of drain 
valves installed would require approximately two leak tests of one 
drain valve and three leak tests of the other drain valve each year. 
Because of the varied costs that may be incurred by different 
operators, we have provided estimated costs of the leak tests that 
range from between $1,170 and $5,850 per airplane per year. No

[[Page 15242]]

change is necessary to the final rule in this regard.

Request To Limit Leak Test Extensions Specified in Paragraph (b)

    The commenter states that, in the recent past, the FAA provided 
rationale for not granting an across-the-board leak check extension for 
a manufacturer when the FAA stated that, ``it recognizes that varying 
aspects of each airlines operational environment and the human factors 
associated with maintenance procedures means that equal results for all 
airlines would not necessarily result.'' Therefore, the commenter 
states that the FAA encouraged operators who had proven and effective 
maintenance programs to individually obtain approval for increased leak 
check intervals. The commenter agrees with that approach and requests 
that any extensions of the leak test intervals specified in paragraph 
(b) of the supplemental NPRM be granted only on an airline-by-airline 
basis, rather than across-the-board leak check extensions for certain 
service panel valves.
    We do not agree with the commenter's request. Since the time that 
we granted extension of leak test intervals on an operator-by-operator 
basis, sufficient data has been submitted to justify the conclusion 
that certain service panel valves, if properly maintained, can perform 
satisfactorily under different operating conditions and maintenance 
programs. Further, to ensure that leakage does not become a problem in 
conditions that may not be foreseen, the requirement to repair any leak 
or to placard the lavatory inoperative before further flight should 
ensure the operational safety of the fleet. 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.

Changes to 14 CFR Part 39/Effect on the AD

    On July 10, 2002, the FAA issued a new version of 14 CFR part 39 
(67 FR 47997, July 22, 2002), which governs the FAA's airworthiness 
directives system. The regulation now includes material that relates to 
altered products, special flight permits, and alternative methods of 
compliance. However, for clarity and consistency in this final rule, we 
have retained the language of the supplemental NPRM regarding that 
material.

Change to Labor Rate Increase

    After the supplemental NPRM was issued, we reviewed the figures we 
use to calculate the labor rate to do the required actions. To account 
for various inflationary costs in the airline industry, we find it 
appropriate to increase the labor rate used in these calculations from 
$60 per work hour to $65 per work hour. The economic impact 
information, below, has been revised to reflect this increase in the 
specified hourly labor rate.

Cost Impact

    There are approximately 2,410 Model 737 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 1,031 
airplanes of U.S. registry and 110 U.S. operators will be affected by 
this AD.
    The required waste drain system leak test and outer cap inspection 
will take approximately 6 work hours per airplane to accomplish, at an 
average labor rate of $65 per work hour. Based on these figures, the 
cost impact on U.S. operators of these requirements of this AD is 
estimated to be $402,090, or $390 per airplane, per test/inspection.
    Certain airplanes (i.e., those that have ``donut'' type drain 
valves installed) may be required to be leak tested as many as 15 times 
each year. Certain other airplanes having other valve configurations 
will be required to be leak tested as few as 3 times each year. Some 
airplanes that have various combinations of drain valves installed will 
require approximately 2 leak tests of 1 drain valve and 3 leak tests of 
the other drain valve each year. Based on these figures, the annual 
(recurring) cost impact of the required repetitive leak tests on U.S. 
operators is estimated to be between $1,170 and $5,850, per airplane 
per year.
    With regard to replacement of ``donut'' type drain valves, the cost 
of a new valve is approximately $1,200. However, the number of leak 
tests for an airplane that is flown an average of 3,000 flight hours a 
year is thereby reduced from 15 tests to 3 tests. The cost reduction 
because of the number of tests required is approximately equal to the 
cost of the replacement valve. Therefore, no additional cost is 
incurred because of this change.
    We estimate that it will take approximately 1 work hour per 
airplane lavatory drain to accomplish a visual inspection of the 
service panel drain valve cap/door seal and seal mating surfaces, at an 
average labor cost of $65 per work hour. As with leak tests, certain 
airplanes will be required to be visually inspected as many as 15 times 
or as few as 3 times each year. Based on these figures, the annual 
(recurring) cost impact of the required repetitive visual inspections 
on U.S. operators is estimated to be between $195 and $975 per 
airplane, per year.
    The required installation of the flush/fill line cap will take 
approximately 1 work hour per cap to accomplish, at an average labor 
rate of $65 per work hour. The cost of required parts will be $275 per 
cap. There is an average of 2.5 caps per airplane. Based on these 
figures, the cost impact on U.S. operators of these requirements of 
this AD is estimated to be $875,500, or $850 per airplane.
    The addition of the seal change requirement to paragraph (a) of 
this AD will require approximately 2 work hours to accomplish, at an 
average labor cost of $65 per hour. The cost of required parts will be 
$200 per each seal change. Based on these figures, the cost impact on 
U.S. operators of these requirements of this AD is estimated to be 
$340,230, or approximately $330 per airplane per year.
    The number of required work hours, as indicated above, is presented 
as if the accomplishment of the actions required in this AD were to be 
conducted as ``stand alone'' actions. However, in actual practice, 
these actions could be accomplished coincidentally or in combination 
with normally scheduled airplane inspections and other maintenance 
program tasks. Therefore, the actual number of necessary ``additional'' 
work hours will be minimal in many instances. Additionally, any costs 
associated with special airplane scheduling should be minimal.
    In addition to the costs discussed above, for those operators who 
elect to comply with paragraph (d) of this AD, we estimate that it will 
take approximately 40 work hours per operator to incorporate the 
lavatory drain system leak test procedures into the maintenance 
programs, at an average labor cost of $65 per work hour. Based on these 
figures, the cost impact of the maintenance revision requirement of 
this AD action on the 110 U.S. operators is estimated to be $286,000, 
or $2,600 per operator.
    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

[[Page 15243]]

actions represent only the time necessary to perform the specific 
actions actually required by the AD. These figures typically do not 
include incidental costs, such as the time required to gain access and 
close up, planning time, or time necessitated by other administrative 
actions.
    We recognize that the obligation to maintain aircraft in an 
airworthy condition is vital, but sometimes expensive. Because ADs 
require specific actions to address specific unsafe conditions, they 
appear to impose costs that would not otherwise be borne by operators. 
However, because of the general obligation of operators to maintain 
aircraft in an airworthy condition, this appearance is deceptive. 
Attributing those costs solely to the issuance of this AD is 
unrealistic because, in the interest of maintaining safe aircraft, 
prudent operators would accomplish the required actions even if they 
were not required to do so by the AD.
    A full cost-benefit analysis has not been accomplished for this AD. 
As a matter of law, in order to be airworthy, an aircraft must conform 
to its type design and be in a condition for safe operation. The type 
design is approved only after the FAA makes a determination that it 
complies with all applicable airworthiness requirements. In adopting 
and maintaining those requirements, the FAA has already made the 
determination that they establish a level of safety that is cost-
beneficial. When the FAA, as in this AD, makes a finding of an unsafe 
condition, this means that the original cost-beneficial level of safety 
is no longer being achieved and that the required actions are necessary 
to restore that level of safety. Because this level of safety has 
already been determined to be cost-beneficial, a full cost-benefit 
analysis for this AD would be redundant and unnecessary.

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, Safety.

Adoption of the Amendment

0
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

0
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]

0
2. Section 39.13 is amended by removing amendment 39-6223 (54 FR 21933, 
May 22, 1989), and by adding a new airworthiness directive (AD), 
amendment 39-13544, to read as follows:

2004-06-18 Boeing: Amendment 39-13544. Docket 95-NM-111-AD. 
Supersedes AD 89-11-03, Amendment 39-6223.

    Applicability: All Model 737-100, -200, -300, -400 and -500 
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 (h) 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 engine damage, airframe damage, and/or hazard to 
persons or property on the ground as a result of ``blue ice'' that 
has formed from leakage of the lavatory drain system or flush/fill 
systems and dislodged from the airplane, accomplish the following:

Replacing Valve Seals and Performing Leak Tests

    (a) Except as provided by paragraph (d) of this AD, accomplish 
the applicable requirements of paragraphs (a)(1) through (a)(6) of 
this AD at the time specified in each paragraph. If the waste drain 
system incorporates more than one type of valve, only one of the 
waste drain system leak test procedures (the one that applies to the 
equipment with the longest leak test interval) must be conducted at 
each service panel location. Except as provided in paragraphs (b) 
and (c) of this AD, the waste drain system valve leak tests 
specified in this AD shall be performed in accordance with the 
following requirements: fluid shall completely cover the upstream 
end of the valve being tested; the direction of the 3 pounds per 
square inch differential pressure (PSID) shall be applied across the 
valve in the same direction as occurs in flight; the other waste 
drain system valves shall be open; and the minimum time to maintain 
the differential pressure shall be 5 minutes.
    (1) Replace the valve seals in accordance with the applicable 
schedule specified in paragraph (a)(1)(i), (a)(1)(ii), or 
(a)(1)(iii) of this AD. If an in-line drain valve as specified in 
paragraph (a)(1)(i) of this AD is installed in the same lavatory 
drain line as the valves specified per paragraph (a)(1)(ii) or 
(a)(1)(iii) of this AD, seal replacement for the valves specified in 
paragraph (a)(1)(ii) or (a)(1)(iii) of this AD may be performed at 
the seal replacement interval for the in-line drain valve.

    Note 2: The seals and o-rings in the service panel drain valve 
that are to be replaced in accordance with paragraph (a)(1) or 
(d)(1) of this AD are the seals and o-rings that seal against the 
valve door, lid, cap, or ball, which is opened to allow flow through 
the service panel drain valve or in-line drain valve. The seals and 
o-rings in the lavatory flush/fill line valve or cap that are to be 
replaced in accordance with paragraph (a)(5) or (d)(3) of this AD 
are the seals and o-rings that seal against a surface and prevent 
backflow from the lavatory waste tank through the flush/fill line.

    (i) For each lavatory drain system that has an in-line drain 
valve installed, Kaiser Electroprecision part number (P/N) series 
2651-278 or service panel ball valve, Kaiser Electroprecision P/N 
series 2651-357: Replace the seals within 5,000 flight hours after 
the effective date of this AD, or within 48 months after the last 
documented seal change, whichever occurs later. Thereafter, repeat 
the replacement of the seals at intervals not to exceed 48 months.
    (ii) For each lavatory drain system that has a Pneudraulics P/N 
series 9527 valve: Replace the seals within 5,000 flight hours after 
the effective date of this AD, or within 18 months of the last 
documented seal change, whichever occurs later. Thereafter, repeat 
the replacement of the seals at intervals not to exceed 18 months or 
6,000 flight hours, whichever occurs later.
    (iii) For each lavatory drain system that has any other type of 
drain valve: Replace the seals within 5,000 flight hours after the 
effective date of this AD, or within 18 months

[[Page 15244]]

after the last documented seal change, whichever occurs later. 
Thereafter, repeat the replacement of the seals at intervals not to 
exceed 18 months.
    (2) For each lavatory drain system that has an in-line drain 
valve installed having Kaiser Electroprecision P/N series 2651-278, 
or service panel drain valve installed having Kaiser 
Electroprecision P/N series 2651-357, or Pneudraulics P/N series 
9527, or Shaw Aero valve having a P/N or serial number (S/N) as 
listed in Table 1 of this AD: Within 4,500 flight hours after the 
effective date of this AD, or within 4,500 hours after the last 
documented leak test, whichever occurs later, accomplish the 
procedures specified in paragraphs (a)(2)(i) and (a)(2)(ii) of this 
AD. Thereafter, repeat the procedures at intervals not to exceed 18 
months or 4,500 flight hours, whichever occurs later.
    (i) Conduct a leak test of the toilet tank dump valve (in-tank 
valve that is spring loaded closed and operable by a T-handle at the 
service panel) and the in-line drain valve (Kaiser Electroprecision 
P/N series 2651-278) or service panel drain valve (Kaiser 
Electroprecision P/N series 2651-357, or Pneudraulics P/N series 
9527, or Shaw Aero valve having a P/N or serial number (S/N) as 
listed in Table 1 of this AD). The toilet tank dump valve leak test 
must be performed by filling the toilet tank with a minimum of 10 
gallons of water/rinsing fluid and, after a period of 5 minutes, 
testing for leakage. Take precautions to avoid overfilling the tank 
and spilling fluid into the airplane. Except as provided by 
paragraphs (b) and (c) of this AD, the in-line drain valve or 
service panel drain valve leak test must be performed with a minimum 
of 3 PSID applied across the valve in the same direction as occurs 
in flight.
    (ii) If a service panel valve or cap is installed, perform a 
general visual inspection of the service panel drain valve outer 
cap/door seal and the inner seal (if the valve has an inner door 
with a second positive seal), and the seal mating surfaces for wear 
or damage that may allow leakage.

    Note 3: For the purposes of this AD, a general visual inspection 
is defined as: ``A visual examination of an interior or exterior 
area, installation, or assembly to detect obvious damage, failure, 
or irregularity. This level of inspection is made from within 
touching distance unless otherwise specified. A mirror may be 
necessary to enhance visual access to all exposed surfaces in the 
inspection area. This level of inspection is made under normally 
available lighting conditions such as daylight, hangar lighting, 
flashlight, or droplight and may require removal or opening of 
access panels or doors. Stands, ladders, or platforms may be 
required to gain proximity to the area being checked.''


   Table 1.--Shaw Aero Valves Approved for 4,500 Flight Hour Leak Test
                                Interval
------------------------------------------------------------------------
                                          Serial numbers of part number
   Shaw waste drain valve part number       valve approved for  4,500
                                          flight hour leak test interval
------------------------------------------------------------------------
331 Series.............................  All.
10101000B-A-1..........................  0207-0212, 0219, 0226 and
                                          higher.
10101000B-A-1..........................  0001-0206, 0213-0218, and 0220-
                                          0225 that are marked ``SBB38-1-
                                          58,'' and that incorporate the
                                          improvements outlined in Shaw
                                          Service Bulletin 10101000B-38-
                                          1, dated October 7, 1994.
10101000BA2............................  0130 and higher.
10101000BA2............................  0001-0129 that are marked
                                          ``SBB38-1-58,'' and that
                                          incorporate the improvements
                                          outlined in Shaw Service
                                          Bulletin 10101000B-38-1, dated
                                          October 7, 1994.
10101000C-A-1..........................  0277 and higher.
10101000C-A-1..........................  0001-0276 that are marked
                                          ``SBC38-2-58,'' and that
                                          incorporate the improvements
                                          outlined in Shaw Service
                                          Bulletin 10101000C-38-2, dated
                                          October 7, 1994.
10101000CN OR 10101000C-N..............  3649 and higher.
10101000CN OR 10101000C-N..............  0001-3648 that is marked
                                          ``SBC38-2-58,'' and that
                                          incorporate the improvements
                                          outlined in Shaw Service
                                          Bulletin 10101000C-38-2, dated
                                          October 7, 1994.
------------------------------------------------------------------------

    (3) For each lavatory drain system with a lavatory drain system 
valve that incorporates either ``donut'' plug, Kaiser 
Electroprecision P/N 4259-20 or 4259-31; Kaiser Roylyn/Kaiser 
Electroprecision cap/flange P/N 2651-194C, 2651-197C, 2651-216, 
2651-219, 2651-235, 2651-256, 2651-258, 2651-259, 2651-260, 2651-
275, 2651-282, 2651-286; or other FAA-approved equivalent parts; 
accomplish the requirements at the specified times of paragraphs 
(a)(3)(i), (a)(3)(ii), and (a)(3)(iii) of this AD. For the purposes 
of paragraph (a)(3) of this AD, ``equivalent part'' means either a 
``donut'' plug that mates with the cap/flange having part numbers 
listed in this paragraph, or a cap/flange that mates with the 
``donut'' plug having part numbers listed in this paragraph, such 
that the cap/flange and ``donut'' plug are used together as an 
assembled valve.
    (i) Within 200 flight hours after the effective date of this AD, 
and thereafter at intervals not to exceed 200 flight hours, conduct 
leak tests of the toilet tank dump valve and the service panel drain 
valve. The leak test of the toilet tank dump valve must be performed 
by filling the toilet tank with a minimum of 10 gallons of water/
rinsing fluid and testing for leakage after a period of 5 minutes. 
Take precautions to avoid overfilling the tank and spilling fluid on 
the airplane. Except as provided by paragraphs (b) and (c) of this 
AD, the service panel drain valve leak test must be performed with a 
minimum 3 PSID applied across the valve in the same direction as 
occurs in flight.
    (ii) Perform a general visual inspection of the outer door/cap 
and seal mating surface for wear or damage that may cause leakage. 
This inspection shall be accomplished in conjunction with the leak 
tests of paragraph (a)(3)(i) of this AD.
    (iii) Within 5,000 flight hours after the effective date of this 
AD, replace the donut valve (part numbers per paragraph (a)(3) of 
this AD) with another type of FAA-approved valve. Following 
installation of the replacement valve, perform the appropriate leak 
tests and seal replacements at the intervals specified for that 
replacement valve, as applicable.
    (4) For each lavatory drain system not addressed in paragraph 
(a)(2) or (a)(3) of this AD: Within 1,000 flight hours or 6 months 
after the effective date of this AD, whichever occurs later, 
accomplish the actions specified in paragraphs (a)(4)(i) and 
(a)(4)(ii) of this AD. Thereafter, repeat those actions at intervals 
not to exceed 1,000 flight hours or 6 months, whichever occurs 
later.
    (i) Conduct a leak test of the toilet tank dump valve and the 
service panel drain valve. The toilet tank dump valve leak test must 
be performed by filling the toilet tank with a minimum of 10 gallons 
of water/rinsing fluid and, after a period of 5 minutes, testing for 
leakage. Take precautions to avoid overfilling the tank and spilling 
fluid on the airplane. Except as provided by paragraphs (b) and (c) 
of this AD, the service panel drain valve leak test must be 
performed with a minimum of 3 PSID applied across the valve inner 
door/closure device.
    (ii) Perform a general visual inspection of the outer cap/door 
and seal mating surface for wear or damage that may cause leakage.
    (5) For flush/fill lines: Within 5,000 flight hours after the 
effective date of this AD, perform the requirements of paragraph 
(a)(5)(i), (a)(5)(ii), (a)(5)(iii), or (a)(5)(iv) of this AD, as 
applicable. Thereafter, repeat the requirements at intervals not to 
exceed 5,000 flight hours, or 48 months after the last documented 
seal change, whichever occurs later. For airplanes that contain 
auxiliary waste tanks, the leak tests may be performed per one of 
the leak test procedures in

[[Page 15245]]

paragraph (b) or (c) of this AD, or by using the leak test 
procedures without filling the toilet tank bowl half-full of fluid 
per the applicable airplane or component maintenance manual.

    Note 4: The seals/o-rings in the service panel drain valve that 
are to be replaced in accordance with paragraph (a)(1) or (d)(1) of 
this AD are the seals/o-rings that seal against the valve door/lid/
cap/ball, which is opened to allow flow through the service panel 
drain valve or in-line drain valve. The seals/o-rings in the 
lavatory flush/fill line valve or cap that are to be replaced per 
paragraph (a)(5) or (d)(3) of this AD are the seals/o-rings that 
seal against a surface and prevent backflow from the lavatory waste 
tank through the flush/fill line.

    (i) If a lever lock cap is installed on the flush/fill line of 
the subject lavatory, replace the seals on the toilet tank anti-
siphon (check) valve and the flush/fill line cap with new seals. 
Perform a leak test of the toilet tank anti-siphon (check) valve 
with a minimum of 3 PSID across the valve in the same direction as 
occurs in flight, in accordance with paragraph (a)(5)(ii)(A) of this 
AD, as applicable.

    Note 5: The leak test procedure described in Boeing 737 
Maintenance Manual, 38-32-00/501, may be referred to as guidance for 
this test if the toilet tank is filled to the level specified in 
paragraph (a)(5)(ii)(A) of this AD.

    (ii) If a vacuum breaker check valve, Monogram P/N series 3765-
190, or Shaw Aero Devises P/N series 301-000, or other FAA-approved 
vacuum break check valve is installed on the subject lavatory, 
replace the seals/o-rings in the valve. Perform a leak test of the 
vacuum breaker check valve and verify proper operation of the vent 
line vacuum breaker in accordance with paragraphs (a)(5)(ii)(A) and 
(a)(5)(ii)(B) of this AD.
    (A) Leak test the toilet tank anti-siphon valve or the vacuum 
breaker check valve by filling the toilet tank with water/rinsing 
fluid to a level such that the bowl is approximately half full (at 
least 2 inches above the flapper in the bowl.) Apply 3 PSID across 
the valve in the same direction as occurs in flight. The vent line 
vacuum breaker on vacuum breaker check valves must be pinched closed 
or plugged for this leak test. If there is a cap/valve at the flush/
fill line port, the cap/valve must be removed/open during the test. 
Check for leakage at the flush/fill line port for a period of 5 
minutes.
    (B) Verify proper operation of the vent line vacuum breaker by 
filling the tank and testing at the fill line port for back drainage 
after disconnecting the fluid source from the flush/fill line port. 
If back drainage does not occur, replace the vent line vacuum 
breaker or repair the vacuum breaker check valve in accordance with 
the component maintenance manual to obtain proper back drainage. As 
an alternative to the above test technique, verify proper operation 
of the vent line vacuum breaker in accordance with the procedures of 
the applicable component maintenance manual.
    (iii) If a flush/fill ball valve, Kaiser Electroprecision P/N 
series 0062-0009 is installed on the flush/fill line of the subject 
lavatory, replace the seals in the flush/fill ball valve and the 
toilet tank anti-siphon valve with new seals. Perform a leak test of 
the toilet tank anti-siphon valve with a minimum of 3 PSID across 
the valve in the same direction as occurs in flight, in accordance 
with paragraph (a)(5)(ii)(A) of this AD.
    (iv) If an FAA-approved shut-off valve that uses a mechanical or 
electrical devise to prevent overfilling of the toilet tank is 
installed, replace the seals/o-rings in the shut-off valve. Perform 
the leak test of the shut-off valve per the applicable airplane or 
component maintenance manual, or per the procedures specified in 
paragraph (b) or (c) of this AD.
    (6) As a result of the leak tests and inspections required by 
paragraph (a) of this AD, or if evidence of leakage is found at any 
other time, accomplish the requirements of paragraph (a)(6)(i), 
(a)(6)(ii), or (a)(6)(iii), as applicable.
    (i) If a leak is discovered, prior to further flight, repair the 
leak. Prior to further flight after repair, perform the appropriate 
leak test, as applicable. Additionally, prior to returning the 
airplane to service, clean the surfaces adjacent to where the 
leakage occurred to clear them of any horizontal fluid residue 
streaks; such cleaning must be to the extent that any future 
appearance of a horizontal fluid residue streak will be taken to 
mean that the system is leaking again.

    Note 6: For purposes of this AD, ``leakage'' is defined as any 
visible leakage, if observed during a leak test. At any other time 
(than during a leak test), ``leakage'' is defined as the presence of 
ice in the service panel, or horizontal fluid residue streaks/ice 
trails originating at the service panel. The fluid residue is 
usually, but not necessarily, blue in color.

    (ii) If any worn or damaged seal is found, or if any damaged 
seal mating surface is found, prior to further flight, repair or 
replace it with a new seal, in accordance with the valve 
manufacturer's maintenance manual.
    (iii) In lieu of performing the requirements of paragraph 
(a)(6)(i) or (a)(6)(ii) of this AD: Before further fight, drain the 
affected lavatory system and placard the lavatory inoperative until 
repairs can be accomplished.

One Alternative to Accomplishing Test Procedures

    (b) As an alternative to the test procedures for service panel 
drain valves and in-line drain valves specified in paragraph (a) or 
(d) of this AD, and flush/fill line valves as specified in paragraph 
(a)(5) or (d)(3) of this AD, a vacuum leak test may be done in 
accordance with ``Shaw Aero Devices Document ILS-193C (Operation 
Instructions for the Waste Drain Valve Inner Flapper and Lavatory 
Rinse/Fill Valve Leak Test Tool), Revision C, dated July 1999. The 
tests shall be conducted with a minimum of 3 PSI differential 
pressures across the valve seal being tested in the same direction 
as occurs in flight. The duration of the test shall be 5 minutes. 
The test may be conducted with fluid completely covering the seal to 
be tested and checked for fluid leakage, or by subjecting the seal 
to a vacuum without fluid present, and checking for loss of vacuum. 
Any movement of the vacuum gauge needle indicates loss of vacuum and 
constitutes failure of the test. Failure of the test also occurs if 
fluid is behind the valve being tested and any leakage of fluid past 
the valve occurs during the test. Operators should note that the 
test rig may not work for all valve types. Confirm compatibility of 
the test rig to the valve by verifying compatibility with the 
manufacturer(s) of the test rig and valve. Other leak test tools may 
be used for this test if approved per paragraph (h) of this AD.

Another Alternative to Accomplishing Test Procedures

    (c) As an alternative to the test procedures for service panel 
drain valves and in-line drain valves specified in paragraph (a) or 
(d) of this AD, and flush/fill line valves as specified in paragraph 
(a)(6) or (d)(3) of this AD, a vacuum test may be done in accordance 
with ``Operating Instructions for Lavatory Waste Drain Valve and 
Flush/Fill Valve Leak Test Tool,'' AAXICO Industries, Ltd., Document 
AI 18, Issue 4, dated January 2002. The test shall be conducted with 
a minimum of 3 PSI differential pressures across the valve seal 
being tested in the same direction as occurs in flight. The duration 
of the tests shall be 5 minutes. The test may be conducted with 
fluid completely covering the seal to be tested and checked for 
fluid leakage, or by subjecting the seal to a vacuum without fluid 
present, and checking for loss of vacuum. Any movement of the vacuum 
gauge needle indicates loss of vacuum and constitutes failure of the 
test. Failure of the test also occurs if fluid is behind the valve 
being tested and any leakage of fluid past the valve occurs during 
the test. Operators should note that the test rig might not work for 
all valve types. Confirm compatibility of the test rig to the valve 
by verifying compatibility with the manufacturer(s) of the test rig 
and valve. Other leak test tools may be used for this test if 
approved per paragraph (h) of this AD.

Revising the FAA-Approved Maintenance Program

    (d) As an alternative to the requirements of paragraph (a) of 
this AD, operators may revise the FAA-approved maintenance program 
to include the requirements specified in paragraphs (d), (f), and 
(g) of this AD, which constitutes terminating action for the AD. 
However, until the FAA-approved maintenance program is revised, 
operators must accomplish the requirements of paragraph (a) of this 
AD. If the waste drain system incorporates more than one type of 
valve, only one of the waste drain system leak test procedures (the 
one that applies to the equipment with the longest leak test 
interval) must be conducted at each service panel location. The 
waste drain system valve leak tests specified in paragraphs (a) and 
(d) of this AD shall be performed in accordance with the following 
requirements: Fluid shall completely cover the upstream end of the 
valve being tested unless a vacuum test is being performed in 
accordance with paragraph (b) or (c) of this AD; the direction of 
the 3 PSID shall be applied across the valve in the same direction 
as occurs in flight; the other waste drain system valves

[[Page 15246]]

shall be open; and the minimum time to maintain the differential 
pressure shall be 5 minutes. A differential pressure greater than 3 
psi may be used if specified by procedures referenced in paragraph 
(b) or (c) of this AD.
    (1) Replace the valve seals in accordance with the applicable 
schedule specified in paragraph (d)(1)(i), (d)(1)(ii), or 
(d)(1)(iii) of this AD. If an in-line drain valve as specified in 
paragraph (d)(1)(i) of this AD is installed in the same lavatory 
drain line as the valves specified in paragraph (d)(1)(ii) or 
paragraph (d)(1)(iii) of this AD, seal replacement for the valves 
specified in paragraphs (d)(1)(ii) and (d)(1)(iii) of this AD may be 
performed at the seal replacement interval for the in-line drain 
valve. (See Note 2 of this AD.)
    (i) For each lavatory drain system that has an in-line drain 
valve installed, Kaiser Electroprecision P/N series 2651-278 or 
service panel ball valve installed, Kaiser Electroprecision P/N 
series 2651-357: Replace the seals within 5,000 flight hours after 
the effective date of this AD, or within 48 months of the last 
documented seal change, whichever occurs later. Thereafter, repeat 
the replacement of the seals at intervals not to exceed 48 months.
    (ii) For each lavatory drain system that has a Pneudraulics P/N 
series 9527 valve: Replace the seals within 5,000 flight hours after 
the effective date of this AD, or within 18 months of the last 
documented seal change, whichever occurs later. Thereafter, repeat 
the replacement of the seals at intervals not to exceed 18 months or 
6,000 flight hours, whichever occurs later.
    (iii) For each lavatory drain system that has any other type of 
drain valve: Replace the seals within 5,000 flight hours after the 
effective date of this AD, or within 18 months of the last 
documented seal change, whichever occurs later. Thereafter, repeat 
the replacement of the seals at intervals not to exceed 18 months.
    (2) Conduct periodic leak tests of the lavatory drain systems in 
accordance with the applicable schedule specified in paragraph 
(d)(2)(i), (d)(2)(ii), or (d)(2)(iii) of this AD. Only one of the 
waste drain system leak test procedures (the one that applies to the 
equipment with the longest leak test interval) must be conducted at 
each service panel location.
    (i) For each lavatory drain system that has an in-line drain 
valve installed having Kaiser Electroprecision P/N series 2651-278; 
service panel drain valve installed having Kaiser Electroprecision 
P/N series 2651-357; Pneudraulics part number series 9527; or Shaw 
Aero P/N/S/N as listed in Table 1 of this AD: Within 5,000 flight 
hours after the effective date of this AD, or within 5,000 hours of 
the last documented leak test, whichever occurs later, accomplish 
the procedures specified in paragraphs (d)(2)(i)(A) and (d)(2)(i)(B) 
of this AD. Thereafter repeat the procedures at intervals not to 
exceed 18 months or 5,000 flight hours, whichever occurs later.
    (A) Conduct a leak test of the toilet tank dump valve (in-tank 
valve that is spring loaded closed and operable by a T-handle at the 
service panel) and the in-line drain valve (Kaiser Electroprecision 
P/N series 2651-278) or the service panel drain valve (Kaiser 
Electroprecision P/N series 2651-357, Pneudraulics part number 
series 9527, or Shaw Aero Part Number/Serial Number as listed in 
Table 1 of this AD). The leak test of the toilet tank dump valve 
must be performed by filling the toilet tank with a minimum of 10 
gallons of water/rinsing fluid and testing for leakage after a 
period of 5 minutes. Take precautions to avoid overfilling the tank 
and spilling fluid on the airplane. Except as provided by paragraphs 
(b) and (c) of this AD, the in-line drain valve or service panel 
drain valve leak test must be performed with a minimum of 3 PSID 
applied across the valve in the same direction as occurs in flight.
    (B) If a service panel valve or cap is installed, perform a 
general visual inspection of the service panel drain valve outer 
cap/door seal and the inner seal (if the valve has an inner door 
with a second positive seal), and the seal mating surfaces, for wear 
or damage that may allow leakage.
    (ii) For each lavatory drain system with a lavatory drain system 
valve that incorporates either ``donut'' plugs Kaiser 
Electroprecision P/N 4259-20 or 4259-31; Kaiser Roylyn/Kaiser 
Electroprecision cap/flange part number 2651-194C, 2651-197C, 2651-
216, 2651-219, 2651-235, 2651-256, 2651-258, 2651-259, 2651-260, 
2651-275, 2651-282, 2651-286; or other FAA-approved equivalent part; 
accomplish the requirements at the times specified in paragraphs 
(d)(2)(ii)(A), (d)(2)(ii)(B), and (d)(2)(ii)(C) of this AD. For the 
purposes of this paragraph, (d)(2)(ii), ``FAA-approved equivalent 
part'' means either a ``donut'' plug that mates with the cap/flange 
having P/Ns listed in this paragraph, or a cap/flange that mates 
with the ``donut'' plug having P/Ns listed in this paragraph, such 
that the cap/flange and ``donut'' plug are used together as an 
assembled valve.
    (A) Within 200 flight hours after the effective date of this AD, 
or within 200 flight hours after the last documented leak test, 
whichever occurs later, conduct leak tests of the toilet tank dump 
valve and the service panel drain valve. Thereafter, repeat the 
tests at intervals not to exceed 200 flight hours. The toilet tank 
dump valve leak test must be performed by filling the toilet tank 
with a minimum of 10 gallons of water/rinsing fluid and, after a 
period of 5 minutes, testing for leakage. Take precautions to avoid 
overfilling the tank and spilling fluid on the airplane. Except as 
provided in paragraphs (b) and (c) of this AD, the service panel 
drain valve leak test must be performed with a minimum of 3 PSI 
differential applied across the valve in the same direction as 
occurs in flight.
    (B) Perform a visual inspection of the outer door/cap and seal 
mating surface for wear or damage that may cause leakage. Perform 
this inspection in conjunction with the leak tests specified in 
paragraph (d)(2)(ii)(A).
    (C) Within 5,000 flight hours after the effective date of this 
AD, replace the donut valve with another type of FAA-approved valve. 
Following replacement of the valve, perform the subsequent leak 
tests and seal replacements at the intervals specified for the new 
valve.
    (iii) For each lavatory drain system that incorporates any other 
type of approved valves: Within 1,000 flight hours after the 
effective date of this AD, or within 1,000 flight hours of the last 
documented leak test, whichever occurs later, accomplish the 
requirements of paragraphs (d)(2)(iii)(A) and (d)(2)(iii)(B) of this 
AD. Thereafter, repeat the requirements at intervals not to exceed 
1,000 flight hours.
    (A) Conduct leak tests of the toilet tank dump valve and the 
service panel drain valve. The toilet tank dump valve leak test must 
be performed by filling the toilet tank with a minimum of 10 gallons 
of water/rinsing fluid and, after a period of 5 minutes, testing for 
leakage. Take precautions to avoid overfilling the tank and spilling 
fluid on the airplane. The service panel drain valve leak test must 
be performed with a minimum of 3 PSID applied across the valve in 
the same direction as occurs in flight. If the service panel drain 
valve has an inner door with a second positive seal, only the inner 
door must be tested.
    (B) Perform a general visual inspection of the outer cap/door 
and seal mating surface for wear or damage that may cause leakage.
    (3) For flush/fill lines: Within 5,000 flight hours after the 
effective date of this AD, perform the requirements of paragraph 
(d)(3)(i), (d)(3)(ii), (d)(3)(iii), or (d)(3)(iv), as applicable. 
Thereafter, repeat the requirements at intervals not to exceed 5,000 
flight hours, or 48 months after the last documented seal change, 
whichever occurs later. For airplanes that contain auxiliary waste 
tanks, the leak tests may be performed per one of the leak test 
procedures in paragraph (b) or (c) of this AD, or by performing the 
leak test procedures without filling the toilet tank bowl half-full 
of fluid per the applicable airplane or component maintenance 
manual.
    (i) If a lever lock cap is installed on the flush/fill line of 
the subject lavatory, replace the seals on the toilet tank anti-
siphon (check) valve and the flush/fill line cap. Perform a leak 
test of the toilet tank anti-siphon (check) valve with a minimum of 
3 PSID across the valve in the same direction as occurs in flight, 
as specified in paragraph (d)(3)(ii)(A) of this AD.
    (ii) If a vacuum breaker check valve having Monogram P/N series 
3765-190; Shaw Aero Devices P/N series 301-0009-01; or other FAA-
approved vacuum breaker check valve is installed on the subject 
lavatory; replace the seals/o-rings in the valve. Prior to further 
flight, leak test the vacuum breaker check valve, and test for 
proper operation of the vent line vacuum breaker as specified in 
paragraphs (d)(3)(ii)(A) and (d)(3)(ii)(B) of this AD.
    (A) Leak test the toilet tank anti-siphon valve or the vacuum 
breaker check valve by filling the toilet tank with water/rinsing 
fluid to a level such that the bowl is approximately half full (at 
least 2 inches above the flapper in the bowl). Except as provided in 
paragraphs (b) and (c) of this AD, apply 3 PSID across the valve in 
the same direction as occurs in flight. The vent line vacuum breaker 
on vacuum breaker check valves must be pinched closed or plugged for 
this leak test. If there is a cap/valve at the flush/fill line port, 
the cap/valve must be removed/opened during the test. Test for 
leakage at the flush/fill line port for a period of 5 minutes.


[[Page 15247]]


    Note 7: The leak test procedure in the appropriate section of 
Boeing 737 Maintenance Manual 38-32-00 may be used as guidance for 
this test if the toilet tank is filled approximately half full (at 
least 2 inches above the flapper in the bowl).

    (B) Verify proper operation of the vent line vacuum breaker by 
filling the tank and testing at the fill line port for back drainage 
after disconnecting the fluid source from the flush/fill line port. 
If back drainage does not occur, replace the vent line vacuum 
breaker or repair the vacuum breaker check valve in accordance with 
the component maintenance manual as required to obtain proper back 
drainage.
    (iii) If a flush/fill ball valve, Kaiser Electroprecision P/N 
series 0062-009 is installed on the flush/fill line of the subject 
lavatory, replace the seals in the flush/fill ball valve and the 
toilet tank anti-siphon valve. Perform a leak test of the toilet 
tank anti-siphon valve in accordance with paragraph (d)(3)(ii)(A) of 
this AD.
    (iv) If an FAA-approved shut-off valve that uses a mechanical or 
electrical device to prevent overfilling the toilet tank is 
installed, replace the seals/o-rings in the shut-off valve. Perform 
a leak test of the shut-off valve per the applicable airplane or 
component maintenance manual, or per the procedures specified in 
paragraph (b) or (c) of this AD.
    (4) Provide procedures for accomplishing visual inspections to 
detect leakage, to be conducted by maintenance personnel at 
intervals not to exceed 4 calendar days or 45 flight hours, which 
ever occurs later.
    (5) Provide procedures for reporting leakage. These procedures 
shall provide that any ``horizontal blue streak'' findings must be 
reported to maintenance and that, prior to further flight, the 
leaking system shall either be repaired, or be drained and placarded 
inoperative.
    (6) Provide training programs for maintenance and servicing 
personnel that include information on ``blue ice awareness'' and the 
hazards of ``blue ice.''
    (7) If a leak is discovered during a leak test required by 
paragraph (d) of this AD; or if evidence of leakage is found at any 
other time; or if repair/replacement of a valve (or valve parts) is 
required as a result of a visual inspection required in accordance 
with this AD; prior to further flight, accomplish the requirements 
of paragraph (d)(7)(i), (d)(7)(ii), or (d)(7)(iii) of this AD, as 
applicable.

    Note 8: For purposes of this AD, ``leakage'' is defined as any 
visible leakage, if observed during a leak test. At any other time 
(than during a leak test), ``leakage'' is defined as the presence of 
ice in the service panel, or horizontal fluid residue streaks/ice 
trails originating at the service panel. The fluid residue is 
usually, but not necessarily, blue in color.

    (i) Repair the leak and, prior to further flight after repair, 
perform a leak test. Additionally, prior to returning the airplane 
to service, clean the surfaces adjacent to where the leakage 
occurred to clear them of any horizontal fluid residue streaks; such 
cleaning must be to the extent that any future appearance of a 
horizontal fluid residue streak will be taken to mean that the 
system is leaking again.
    (ii) Repair or replace the valve or valve parts.
    (iii) In lieu of either paragraph (d)(7)(i) or (d)(7)(ii), drain 
the affected lavatory system and placard the lavatory inoperative 
until repairs can be accomplished.

Requesting Extension of Leak Test Intervals

    (e) Requests for extensions of the leak test intervals required 
by paragraph (a) or (d) of this AD must be approved by the Manager, 
Seattle Aircraft Certification (ACO), FAA. Requests for such 
revisions must be submitted to the Manager of the Seattle ACO 
through the FAA Principal Maintenance Inspector (PMI), and must 
include the following information:
    (1) The operator's name;
    (2) A statement verifying that all known cases/indications of 
leakage or failed leak tests are included in the submitted material;
    (3) The type of valve (make, model, manufacturer, vendor part 
number, and serial number);
    (4) The period of time covered by the data;
    (5) The current FAA leak test interval;
    (6) Whether or not seals have been replaced between the seal 
replacement intervals required by this AD;
    (7) Whether or not a service panel drain valve is installed 
downstream of an in-line drain valve, Kaiser Electroprecision P/N 
series 2651-278: Data on a service panel valve installed downstream 
of an in-line drain valve will not be considered as an indicator of 
the reliability of the service panel drain valve because the in-line 
valve prevents potential leakage from reaching the service panel 
drain valve.
    (8) Whether or not leakage has been detected between leak test 
intervals required by this AD, and the reason for leakage (i.e., 
worn seals, foreign materials on sealing surface, scratched or 
damaged sealing surface on valve, etc.); and
    (9) Whether or not any cleaning, repairs, or seal changes were 
performed on the valve prior to conducting the leak test. (If such 
activities have been accomplished prior to conducting the periodic 
leak test, that leak test shall be recorded as a ``failure'' for 
purposes of the data required for this request submission. The 
exception to this is the normally-scheduled seal change in 
accordance with paragraph (a)(1) and (d)(1) of this AD. Performing 
this scheduled seal change prior to a leak test will not cause that 
leak test to be recorded as a failure. Debris removal of major 
blockages done as part of normal maintenance for previous flights is 
also allowable and will not cause a leak test to be recorded as a 
failure. Minor debris removal that is not commonly removed during 
the normal ground maintenance test should not be removed prior to 
the leak test).

    Note 9: Requests for approval of revised leak test intervals may 
be submitted in any format, provided the data give the same level of 
assurance specified in paragraph (e) of this AD. Results of an 
Environmental Quality Analysis (EQA) examination and leak test on a 
randomly selected high-flight-hour valve, with seals that have not 
been replaced during a period of use at least as long as the desired 
interval, may be considered a valuable supplement to the service 
history data, reducing the amount of service data that would 
otherwise be required.


    Note 10: For the purposes of expediting resolution of requests 
for revisions to the leak test intervals, the FAA suggests that the 
requester summarize the raw data; group the data gathered from 
different airplanes (of the same model) and drain systems with the 
same kind of valve; and provide a recommendation from pertinent 
industry group(s) and/or the manufacturer specifying an appropriate 
revised leak test interval.


    Note 11: In cases where changes are made to a valve design 
approved for an extended leak test interval such that a new valve 
dash number or P/N is established for the valve, the FAA may not 
require extensive service history data to approve the new valve to 
the same leak test interval as the previous valve design. The FAA 
will consider similarity of design, the nature of the design 
changes, the nature and amount of testing, and like factors to 
determine the appropriate data requirements and leak test interval 
for a new or revised valve based upon an existing design.

Certain Installations

    (f) For all airplanes: Unless already accomplished, within 5,000 
flight hours after the effective date of this AD, perform the 
actions specified in paragraph (f)(1), (f)(2), (f)(3), or (f)(4) of 
this AD:
    (1) Install an FAA-approved lever/lock cap on the flush/fill 
lines for all lavatories; or
    (2) Install a vacuum break check valve having Monogram P/N 
series 3765-190, Shaw Aero Devises P/N series 301-0009, or other 
FAA-approved vacuum break check valve in the flush/fill lines for 
all lavatories; or
    (3) Install a flush/fill ball valve Kaiser Electroprecision P/N 
series 0062-0009 on the flush/fill lines for all lavatories; or
    (4) Install an FAA-approved shut-off valve that uses a 
mechanical or electrical device on the flush/fill lines for all 
lavatories to prevent overfilling the toilet tank.

For Airplanes Acquired After the Effective Date of This AD

    (g) For any affected airplane acquired after the effective date 
of this AD: Before any operator places into service any airplane 
subject to the requirements of this AD, a schedule for the 
accomplishment of the leak tests required by this AD shall be 
established in accordance with either paragraph (g)(1) or (g)(2) of 
this AD, as applicable. After each leak test has been performed 
once, each subsequent leak test must be performed in accordance with 
the new operator's schedule, in accordance with either paragraph (a) 
or (d) of this AD as applicable.
    (1) For airplanes previously maintained in accordance with this 
AD, the first leak test to be performed by the new operator must be 
accomplished in accordance with the previous operator's schedule or 
with the new operator's schedule, whichever would result in the 
earlier accomplishment date for that leak test.
    (2) For airplanes that have not been previously maintained in 
accordance with this AD, the first leak test to be performed by

[[Page 15248]]

the new operator must be accomplished prior to further flight, or in 
accordance with a schedule approved by the FAA PMI, but within a 
period not to exceed 200 flight hours.

Alternative Method of Compliance

    (h) Alternative method(s) of compliance with this AD:
    (1) 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, FAA. Operators shall 
submit their requests through an appropriate FAA PMI, who may add 
comments and then send it to the Manager, Seattle ACO.
    (2) All previously issued alternative methods of compliance 
approved for AD 89-11-03 (54 FR 21933, May 22, 1989) are hereby 
terminated as of the effective date of this AD and are no longer in 
effect.

    Note 12: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.


    Note 13: For any valve that is not eligible for the extended 
leak test intervals of this AD: To be eligible for the extended leak 
test intervals specified in paragraph (a) or (d) of this AD, the 
service history data of the valve must be submitted to the Manager, 
Seattle ACO, with a request for an alternative method of compliance. 
The request should include an analysis of known failure modes for 
the valve, if it is an existing design, and known failure modes of 
similar valves, with an explanation of how design features will 
preclude these failure modes, results of qualification tests, and 
approximately 25,000 flight hours or 25,000 flight cycles of service 
history data which include a winter season, collected in accordance 
with the requirements of paragraph (e) of this AD, or a similar 
program. One of the factors that the FAA will consider in approving 
alternative valve designs is whether the valve meets Boeing 
Specification S417T105 or 10-62213. However, meeting the Boeing 
specification is not a prerequisite for approval of alternative 
valve designs.

Special Flight Permits

    (i) 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.

Effective Date of This AD

    (j) This amendment becomes effective on April 29, 2004.

    Issued in Renton, Washington, on March 19, 2004.
Kevin M. Mullin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-6677 Filed 3-24-04; 8:45 am]
BILLING CODE 4910-13-P