[Federal Register Volume 61, Number 216 (Wednesday, November 6, 1996)]
[Rules and Regulations]
[Pages 57304-57311]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-27395]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-214-AD; Amendment 39-9798; AD 96-22-10]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-9 and DC-9-
80 Series Airplanes, and Model MD-88 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to all McDonnell Douglas DC-9 and DC-9-80 series airplanes, 
and Model MD-88 airplanes, that requires repetitive leak checks of the 
lavatory drain system and repair, if necessary; provides for the option 
of revising the FAA-approved maintenance program to include a schedule 
of leak checks; requires the installation of a cap on the flush/fill 
line; and requires replacement or modification of the vent system 
piping. This amendment is prompted by continuing reports of damage to 
engines and airframes, separation of engines from airplanes, and damage 
to property on the ground, caused by ``blue ice'' that forms from 
leaking lavatory drain systems on transport category airplanes and 
subsequently dislodges from the airplane fuselage. The actions 
specified by this AD are intended to prevent such damage associated 
with the problems of ``blue ice.''

DATES: Effective December 11, 1996. The incorporation by reference of 
certain publications listed in the regulations is approved by the 
Director of the Federal Register as of December 11, 1996.

ADDRESSES: The service information referenced in this AD may be 
obtained from McDonnell Douglas Corporation, 3855 Lakewood Boulevard, 
Long Beach, California 90846, Attention: Technical Publications 
Business Administration, Department C1-L51 (2-60). This information may 
be examined at the Federal Aviation Administration (FAA), Transport 
Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, 
Washington; or at the FAA, Transport Airplane Directorate, Los Angeles 
Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, 
California; or at the Office of the Federal Register, 800 North Capitol 
Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Walter Eierman, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130L, FAA, Los Angeles Aircraft 
Certification Office, 3960 Paramount Boulevard, Lakewood, California 
90712; telephone (310) 627-5336; fax (310) 627-5210.

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 McDonnell Douglas DC-9 and DC-
9-80 series airplanes, and Model MD-88 airplanes was published in the 
Federal Register on December 26, 1995 (60 FR 66764). That action 
proposed to:
    1. require repetitive leak checks of the lavatory drain system and 
repair, if necessary;
    2. provide for the option of revising the FAA-approved maintenance 
program to include a schedule of leak checks;
    3. require the installation of a cap on the flush/fill line; and
    4. require replacement or modification of the vent system piping.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Support for the Proposal

    Two commenter support the proposed rule.

Request to Exclude All-Cargo Configured Airplanes from 
Applicability

    One commenter requests that the applicability of the proposal be 
revised to exclude airplanes operating in an all-cargo configuration, 
where lavatories and lavatory fill/drain systems have been removed.
    The FAA concurs. This final rule requires leak checks of the 
lavatory/fill drain system. However, if no such system is installed on 
the airplane then, obviously, the requirements of the AD cannot be 
performed and, likewise, should not be required. As long as there is 
one lavatory drainage system installed on the airplane, the 
requirements of this AD would still apply. To make this eminently clear 
to affected operators, the FAA has revised the applicability of the 
final rule to clarify that the AD applies to airplanes that are 
equipped with a lavatory drainage system.

Request for Permission to Use Alternative Check Valves on Flush/
Fill Line

    Two commenters request that the proposed rule be revised to allow 
the use of Monogram 4803-86 series check valves on flush/fill lines as 
an alternative to the specified lever/lock cap. These commenters point 
out that Monogram check valves with similar design characteristics were 
approved previously by the FAA as an acceptable alternative item for 
compliance with a similar proposed AD that is applicable to Boeing 
Model 737 series airplanes [reference Docket No. 95-NM-111-AD (60 FR 
55673, November 2, 1995)].
    The FAA concurs with these commenters' request. Paragraphs (a)(5), 
(b)(3), and (d) of the final rule have been revised to specify this. 
Additionally, paragraphs (a)(5) and (b)(3) of the final rule have been 
revised to provide the necessary instructions for replacing the O-rings 
associated with the Monogram 4803-86 series check valve, and for 
testing the check valve for proper operation.

Request to Increase Leak Check Interval for Certain Shaw Aero 
Valves

    One commenter requests that proposed paragraphs (a)(2) and 
(b)(2)(ii) be revised to allow the following Shaw Aero valves to be 
leak checked at 1,000-hour intervals:
     331 series, all serial numbers
     332 series, all serial numbers
The commenter states that these valves have been accepted previously by 
the FAA for a 1,000-hour leak check interval either in accordance with 
AD 94-23-10, which is applicable to Boeing

[[Page 57305]]

Model 727 series airplanes; or a similar proposed rule applicable to 
Boeing Model 737 series airplanes (reference Docket No. 95-NM-111-AD).
    The FAA concurs. Paragraphs (a)(2) and (b)(2)(ii) of this final 
rule have been revised to include these part-numbered valves in the 
requirements for leak checks at 1,000-hour intervals.

Request to Increase Leak Check Interval for Certain Kaiser Valves

    One commenter requests that the proposed repetitive leak check 
interval of 1,000 hours for Kaiser valves having part numbers 0218-0026 
and 0218-0032, be increased to 1,500 hours. As justification for this 
request, the commenter submits qualification and test data.
    The FAA cannot concur, since insufficient data were submitted to 
support a longer inspection interval. Paragraph (g) of the final rule 
provides guidance as to the specific type of data needed to justify 
extensions to the leak check intervals set forth in this AD.
    Two other commenters request that the proposed repetitive leak 
check interval of 1,500 hours for Kaiser valves having part number 
2651-329 series, be increased to 4,500 hours. These commenters state 
that the longer interval has been proposed for this same valve in 
another proposed AD that is applicable to Boeing Model 737 series 
airplanes (reference Docket No. 95-NM-111-AD).
    The FAA concurs with these commenters' request, since this valve 
previously was found to be acceptable for a 4,500-hour leak check 
interval. Paragraph (a)(1) of this final rule has been revised 
accordingly.

Request to Increase Leak Check Interval for Certain Pneudraulics 
Valves

    One commenter requests that the proposed leak check interval of 
1,000 hours for Pneudraulics valves having part number 9527, be 
increased to 2,000 hours. The commenter states that, to date, it has 
accumulated over 580,000 flight hours using this Pneudraulics valve on 
its fleet of airplanes, and there have been only two cases of leaking 
reported. In both cases, the valves were inspected and found to be 
serviceable without repair. This in-service experience should justify a 
longer repetitive check interval.
    The FAA does not concur, since insufficient data were submitted to 
support a longer inspection interval. Paragraph (g) of the final rule 
provides guidance as to the specific type of data needed to justify 
extensions to the leak check intervals set forth in this AD.

Request to Revise Procedure for Dump Valve Leak Check

    One commenter requests that the proposed rule be revised to change 
the procedure for conducting a dump valve leak check so that less fluid 
can be used. This commenter points out that NOTE 2 of the proposal 
states that this leak check is to be accomplished with water/rinsing 
fluid to a level at least 4 inches above the flapper in the bowl. 
However, the commenter notes that this is 2 inches more fluid than is 
needed for similar leak checks of Boeing Model 727 series airplanes 
required by AD 94-23-10 [amendment 39-9073 (59 FR 59124, November 16, 
1994)]. The commenter maintains that the same level of fluid should be 
used so that all leak checks are standardized for all airplanes.
    The FAA does not concur with the commenter's request. The procedure 
to fill the toilet bowl to 4 inches above the flapper (approximately 
\1/2\ full) is also meant to check the tank and the rinse line check 
valves. The FAA finds that performing the test using less fluid does 
not do as complete and adequate a job as is necessary to meet the 
intent of this AD.

Request for Clarification of Leak Check Procedures

    One commenter considers that proposed paragraphs (a)(2)(i) and 
(a)(2)(ii) contradict each other. The former paragraph would require 
that both the inner door/closure device and the outer cap/door must be 
leak checked; while the latter paragraph states that, in lieu of 
pressure testing, the outer seal and seal surface may be visually 
inspected for damage on service panel valves that have an inner seal. 
The commenter states that, to leak check the outer cap, maintenance 
personnel will have to remove the inner seal, thus ruining the seal in 
the process, and there is no guarantee that the tests would be 
performed in a particular sequence to avoid this. The commenter 
contends that a leak check on the outer seal would negate the test on 
the inner seal, and that only a visual inspection of the outer seal is 
necessary.
    The FAA does not concur with the commenters statement that the two 
paragraphs contradict each other. Paragraph (a)(2)(i) calls for a leak 
check of each closure device. For certain types of service panel 
valves, paragraph (a)(2)(ii) merely provides an alternative to that 
leak check, since it states that an inspection of the seal may be 
performed in lieu of the leak check; that paragraph does not require 
that both actions be performed.

Request for Procedures for Performing Leak Check of Lavatory Vent 
System

    One commenter requests that proposed paragraph (e), which would 
require a leak check of the lavatory vent system, be revised to include 
procedures for how these leak checks are to be performed.
    The FAA concurs that inclusion of such procedures is necessary. 
NOTE 2 has been revised to add this information, and a new NOTE 7 has 
been included, which also contains these procedures.

Request to Delete Alternative Visual Inspections

    One commenter requests that the proposal be revised to delete the 
alternative that would allow operators only to visually inspect the 
cover (outer) seal of lavatory drain valves for wear or damage, rather 
than to leak check them. This commenter considers it important that 
leak testing of the drain valves should be performed both on the 
internal portions of the valve and on the cap portions of the valve as 
well. This commenter states that one of the primary emphases of 
addressing the problems of blue ice has been the need for a dual 
sealing valve; by using a dual sealing valve, the reliability of a 
drain valve is doubled, and the potential for blue ice incidents is 
significantly reduced. However, if the FAA would permit only a visual 
inspection of the outer seal, rather than an actual leak test, the 
benefit of the dual sealing valve is lost and safety is compromised 
because ``the potential for a failure through the outer seal that has 
not been tested rises exponentially as it is not being tested.'' The 
commenter considers that the only reason for allowing the visual 
inspection (rather than a leak test) is to provide a cost savings to 
the airlines.
    The FAA does not concur with the commenter's request to delete the 
provision for the alternative procedure. The maintenance procedures 
required by this final rule, as well as the intervals at which 
maintenance is required, were developed in consideration of the design 
and known service experience of the many designs used in lavatory 
systems. The alternative procedure for the visual inspection is allowed 
based on the fact that some valves have an inner seal that is closed 
when the outer cap is closed; for this type of valve, leakage from the 
outer cap could only be checked if the inner seal were removed since, 
when the inner seal is correctly in place, it will prevent any fluid 
from reaching the outer cap seal. It is for this type of valve that the 
AD provides the

[[Page 57306]]

alternative to allow operators to inspect the seal and seal surface of 
the outer cap seal in lieu of performing a leak check of the outer 
seal. The FAA's ultimate determination with regard to this provision 
was not made to provide a cost savings to airlines (as suggested by the 
commenter), but to allow procedures to be accomplished that will 
provide an acceptable level of safety.

Request to Increase Leak Checks at Flush/Fill Port

    One commenter considers that an upstream device with positive shut-
off and anti-siphon features would eliminate the ``blue ice'' that 
occurs at the flush/fill port. The commenter considers that, until such 
time as a new device can be tested and approved, the leak checks and 
inspections of that port should be increased. As further indication of 
a need for more inspections, the commenter states that the currently 
installed flush/fill caps and lever lock cap can be damaged or removed 
by maintenance personnel; additional inspections would ensure that 
these discrepancies are identified and corrected in a timely manner.
    The FAA does not concur with the commenter's request. The FAA 
considers that action is necessary at this time to improve leakage 
conditions at the flush/fill port. The lever lock cap required by this 
AD action will contribute to this goal by being less likely to be left 
unclosed, more difficult to remove, and less prone to falling off, than 
the conventional turn cap. While other suitable devices currently may 
be under development, the FAA finds no justification for delaying this 
AD action while waiting for their availability. However, as those 
devices become available, the FAA may consider requests for the use of 
them as alternative methods of compliance, under the provisions of 
paragraph (g) of this final rule. As for the inspections intervals, the 
FAA developed them based on the best data obtainable to date; however, 
if blue ice originating from this leak path becomes increasingly 
problematic, the FAA may consider further rulemaking to adjust the 
inspection interval as appropriate.

Request to Require Same Maintenance Program for All Operators

    One commenter requests that any future extensions of leak check 
intervals should be based on performance of the hardware involved, not 
on the performance of an individual operator's maintenance program. 
This commenter requests that the FAA consider requiring the same 
maintenance program (relative to the leak checks) for all operators; an 
individual maintenance program should not influence the leak check 
extensions that the FAA gives to any particular valve. While it is 
important to have a proper maintenance program to ensure reliability of 
the aircraft and the lavatory system, the commenter considers it more 
important to realize that a quality valve (regardless of the 
maintenance program) is what increases reliability--not the 
``maintenance program'' itself. A quality valve is not affected by the 
service personnel. The best of maintenance programs can be compromised 
for any number of reasons due to necessary human involvement; however, 
hardware, if properly designed has a built-in safe integrity.
    The FAA does not concur with the commenter's request. The FAA 
considers that hardware design and maintenance are both factors in the 
effective prevention of leakage at the lavatory service panel. This AD 
has been structured to give ``credit'' for both of these factors in 
determining appropriate leak check intervals. Although the FAA could 
require the same maintenance program of all airlines, 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. This AD allows 
airlines who have proven, effective maintenance programs to obtain 
``credit'' (i.e., in the form of increased leak check intervals) for 
their programs.

Request to Require Leak Checks of All Outer Cap/Door Seals

    One commenter requests that the proposal be revised to require that 
all seals that could potentially come into contact with the effluent 
that causes blue ice be leak tested. The commenter points specifically 
to proposed paragraph (b)(2)(iii), which states that, if an operator 
uses ``donut'' -type valves, both the donut and the outer cap/door seal 
must be leak checked. Other provisions of the proposed rule, however, 
would require only a visual inspection of the outer cap/door seal on 
other types of valves. This commenter states that it is not in the best 
interest of eliminating blue ice not to leak check every seal.
    The FAA acknowledges this commenter's concern, and does not 
disagree with the suggestion that testing every seal could lower the 
possibility of the formation of blue ice. It is obvious that more 
testing, either by testing of every seal or by increasing the frequency 
of tests, theoretically could reduce the potential for blue ice to 
occur. However, in this AD, the FAA has attempted to establish a 
reasonable test program for each configuration of valve, in 
consideration of the unique design of the individual valve assemblies 
and the service history data relative to each valve. The FAA has 
determined that the program set forth in this AD will achieve an 
acceptable level of safety with regard to the problems associated with 
blue ice.

Request to Require that ``Donut'' Assemblies Be Removed from 
Service

    One commenter requests that the proposal be revised to require that 
all ``donut''-type valve assemblies be removed from service. This 
commenter contends that this type of valve has a long history of poor 
performance, and it is commonplace for the ``donut'' component of the 
valve not to be installed (missing), thereby rendering the valve 
inoperative. The commenter states that during ground service, the donut 
component sometimes washes into the lavatory service cart and is not 
replaced into the lavatory drain panel valve until the next inspection. 
The commenter maintains that blue ice will continue to fall if ``this 
archaic approach to valve technology continues to be used.''
    The FAA does not concur with the commenter's request. The FAA 
acknowledges that the ``donut'' design is neither the latest in 
technology standards nor the most effective valve assembly. However, 
based on the best data obtainable to date, the FAA has determined that 
a leak check of ``donut''-type valve assemblies at intervals of 200 
flight hours will ensure that the valve is monitored adequately to 
provide an acceptable level of safety. [This leak check requirement is 
stated in paragraph (a)(4) of the final rule.] The FAA is continuing to 
review the on-going service history of these valves, and may consider 
further rulemaking to require their removal from service if future data 
justify such an action.

Request to Require Standard Nomenclature for Primary vs. Secondary 
Seals

    One commenter requests that the FAA require all valve manufacturers 
to use standard nomenclature for primary and secondary seals. This 
commenter asserts that the first seal that the effluent comes in 
contact with should be referred to as the ``primary'' seal; the cover 
seal should be referred to as the ``secondary'' seal. This commenter 
states that certain valve manufacturers have begun to call the cover 
seal on their valves ``primary'' seals. This can create problems, since

[[Page 57307]]

paragraph (b)(2)(i)(B) of the proposal would require that the outer 
cap/door seal is only visually inspected and, thus, the ``primary'' 
seal on this manufacturer's assemblies is never pressure tested. The 
commenter maintains that the FAA should not allow the primary seal to 
go untested.
    The FAA acknowledges this commenter's concerns, but finds that no 
change to the AD is necessary. The FAA does not control the 
nomenclature that manufacturers choose to identify seals in their valve 
assemblies; further, the FAA does not consider it appropriate that what 
a manufacturer chooses to call a seal should be used to determine the 
actions required by this AD. The FAA finds that the wording used in the 
requirement for the visual inspection is very specific as to which 
component of the valve assembly is to be inspected (the service panel 
drain valve outer cap/door seal and the inner seal if the valve has an 
inner door/closure device with a second positive seal). The requirement 
deliberately does not contain the words ``primary'' or ``secondary'' in 
referring to seals, since those terms are not specific and, as the 
commenter points out, are used differently by different manufacturers.

Request to Revise Data Collection Guidance

    One commenter requests that the data collection guidance iterated 
in proposed paragraph (c) be revised. Specifically, the commenter asks 
that language contained in proposed paragraph (c)(8) that refers to 
removal of debris done as part of maintenance be modified to reflect 
more specifically what occurs during normal ground servicing. The 
commenter states that normally the only debris that is removed during 
ground servicing is what could be called ``major'' blockage items; 
simple things, such as toilet paper or other minor debris, are left in 
place as part of normal ground maintenance. In light of this, the 
tested condition from which data is gathered should represent the 
condition that the system would be in during normal operations. The 
commenter requests that paragraph (c)(8) be changed to specify this.
    The FAA concurs. The commenter's suggested revision will provide 
useful clarification of the intent of the requirement. Paragraph (c)(8) 
of the final rule has been revised to specify that only major blockages 
should be removed prior to a leak check test, and that minor debris 
removal that is not commonly removed during normal ground maintenance 
check should not be removed prior to the leak check.

Request Not to Consider Test Data with Drain Valves Below Ball 
Valves

    One commenter requests that proposed paragraph (c) be revised to 
specify that test data on a panel valve that is below a ball valve is 
not valid data, and that such data should not be included in any test 
data submitted to the FAA for purposes of requesting an increase in a 
leak check interval for any valve. This commenter states that a panel 
valve below a ball valve would not be subject to the same operational 
requirements as a panel valve without a ball valve ahead of it in the 
drain line, as the highly reliable ball valve would always be stopping 
any leaks.
    The FAA concurs. A panel valve installation with a ball valve is 
not subject to the same operating environment as an panel valve 
installation without a ball valve. Therefore, any data collected on the 
former type of valve installation would not be valid as justification 
for an extended leak check interval for the latter type of valve 
installation. To clarify this, the FAA has revised NOTE 9 of the final 
rule (which addressed collecting data for leak check intervals) to 
include information indicating that the configuration of the entire 
drain system on the airplanes used in evaluating a drain valve leak 
check interval should be defined. This way, it can be assured that the 
data submitted is representative of the applications where the drain 
valve will be used.

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    There are approximately 2,097 Model DC-9 and DC-9-80 series 
airplanes and Model MD-88 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 1,191 airplanes of U.S. 
registry and 47 U.S. operators, will be affected by this AD.
    1. Leak checks. It will take approximately 4 work hours per 
airplane lavatory drain to accomplish each leak check, at an average 
labor cost of $60 per work hour. There normally are 2 drains per 
airplane. Depending upon the type of valves installed and the flight 
utilization rate of the airplane, an airplane subject to this AD could 
be required to be inspected as few as 2 times per year or as many as 15 
times per year. Based on these figures, the cost impact of the leak 
check requirement on U.S. operators will be between $960 and $7,200 per 
airplane per year.
    2. Inspections. Should an operator elect to perform the inspection 
of the service panel drain valve cap/door seal and seal mating surface, 
the inspection will take approximately 1 work hour to accomplish, at an 
average labor cost of $60 per work hour. Depending upon the type of 
valves installed and the flight utilization rate of the airplane, an 
airplane subject to this AD could be required to be inspected as few as 
2 times per year or as many as 15 times per year. Based on these 
figures, the cost impact of the inspection requirement on U.S. 
operators will be between $120 and $1,800 per airplane per year.
    3. Installation of cap on flush/fill line. The proposed 
installation will take approximately 2 work hours to accomplish, at an 
average labor cost of $60 per work hour. The cost of required parts is 
estimated to be $275 per flush/fill line. There are normally 3 flush/
fill lines per airplane. Based on these figures, the cost impact of the 
proposed installation requirement on U.S. operators will be $1,411,335, 
or $1,185 per airplane.
    4. Installation of lavatory vent system replacement/modification. 
The portion of this installation that entails modification of the 
toilet assembly will require between 2 and 4 work hours per airplane to 
accomplish, depending on the brand of toilet involved. The average 
labor cost is estimated to be $60 per work hour. The cost of required 
parts is estimated to be between $83 and $2,121 per airplane. Based on 
these figures, the cost impact of this portion of the required 
installation on U.S. operators will be between $203 and $2,361 per 
airplane.
    The portion of this installation that entails modification of 
lavatory vent lines will require between 15 and 52 work hours per 
airplane to accomplish, depending upon the configuration of the 
airplane, if certain other modifications have already been 
accomplished, and the modification option selected. The average labor 
cost is estimated to be $60 per work hour. The cost of required parts 
is estimated to be between $600 and $13,000 per airplane. Based on 
these figures, the cost impact of this portion of the required 
installation on U.S. operators will be between $1,500 and $16,120 per 
airplane.
    The number of required work hours, as indicated above, is presented 
in this discussion as if the actions required by this AD were to be 
conducted as ``stand

[[Page 57308]]

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 proposed paragraph (b) of this AD action, the FAA 
estimates that it will take approximately 40 work hours per operator to 
incorporate the lavatory drain system leak check procedures into the 
maintenance programs, at an average labor cost of $60 per work hour. 
Based on these figures, the cost impact of the maintenance revision 
requirement of this AD on U.S. operators is estimated to be $2,400 per 
operator.
    The ``cost impact'' figure discussed above is based on assumptions 
that no operator has yet accomplished any of the requirements of this 
AD action, and that no operator would accomplish those actions in the 
future if this AD were not adopted.

Regulatory Impact

    The regulations adopted herein will not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a 
significant economic impact, positive or negative, on a substantial 
number of small entities under the criteria of the Regulatory 
Flexibility Act. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

96-22-10  McDonnell Douglas: Amendment 39-9798. Docket 95-NM-214-AD.

    Applicability: All Model DC-9-10, -20, -30, -40, and -50 series 
airplanes; Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), 
and DC-9-87 (MD-87) series airplanes; and Model MD-88 airplanes; 
equipped with a lavatory drainage system; 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 (g) 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 and dislodged 
from the airplane, accomplish the following:

    Note 2: The leak checks of the toilet dump valve, flush/fill 
line, and lavatory vent system that are required by this AD may be 
performed by filling the toilet tank with water/rinsing fluid to a 
level at least 4 inches above the flapper in the bowl, and checking 
for leakage after a period of 5 minutes.

    (a) Except as provided in paragraph (b) of this AD, accomplish 
the applicable procedures specified in paragraphs (a)(1), (a)(2), 
(a)(3), (a)(4), (a)(5), and (a)(6) of this AD. If the individual 
waste drain system panel incorporates more than one type of valve, 
the inspection interval that applies to that panel is determined by 
the component with the longest inspection interval allowed. Each of 
the components must be inspected or tested at that time at each 
service panel location.
    (1) For each lavatory drain system that has an in-line drain 
valve installed, Kaiser Electroprecision part number series 2651-
329: Within 4,500 flight hours after the effective date of this AD, 
and thereafter at intervals not to exceed 4,500 flight hours, 
accomplish the procedures specified in paragraphs (a)(1)(i) and 
(a)(1)(ii) of this AD:
    (i) Conduct a leak check of the 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. The in-line drain valve leak 
check must be performed with a minimum of 3 pounds per square inch 
differential pressure (PSID) applied across the valve.
    (ii) Visually inspect the service panel drain valve outer cap 
seal and the inner seal (if the valve has an inner door/closure 
device with a second positive seal), and the seal mating surfaces, 
for wear or damage that may allow leakage.
    (2) Within 1,000 flight hours after the effective date of this 
AD, and thereafter at intervals not to exceed 1,000 flight hours, 
accomplish the applicable procedures specified in paragraphs 
(a)(2)(i) and (a)(2)(ii) of this AD for each lavatory drain system 
with a service panel drain valve installed that is listed in Table 
1, below:

                     Table 1.--Valves Requiring Leak Checks at 1,000--Flight Hour Intervals                     
----------------------------------------------------------------------------------------------------------------
               Manufacturer                          Part No.                          Serial No.               
----------------------------------------------------------------------------------------------------------------
Shaw Aero Devices........................  10101000C-A (or higher dash  All serial numbers.                     
                                            number).                                                            
Shaw Aero Devices........................  10101000B-A (or higher dash  All serial numbers.                     
                                            number).                                                            
Shaw Aero Devices........................  10101B-577-1...............  All serial numbers.                     
Shaw Aero Devices........................  10101B-577-2...............  All serial numbers.                     
Shaw Aero Devices........................  331 series.................  All serial numbers.                     
Shaw Aero Devices........................  332 series.................  All serial numbers.                     
Pneudraulics.............................  9527 series................  All serial numbers.                     
----------------------------------------------------------------------------------------------------------------


[[Page 57309]]

    (i) Conduct a leak check of the dump valve and the service panel 
drain valve. The service panel drain valve leak check must be 
performed with a minimum of 3 PSID applied across the valve. Both 
the inner door/closure device and the outer cap/door must be leak 
checked.
    (ii) For service panel valves that have an inner seal: In lieu 
of pressure testing, the outer cap seal and seal surface may be 
visually inspected for damage or wear.
    (3) For each lavatory drain system that has a service panel 
drain valve installed, Shaw Aero Devices part number series 
10101000C [except as specified in paragraph (a)(2) of this AD], or 
Shaw Aero Devices part number 10101000B [except as specified in 
paragraph (a)(2) of this AD]: Within 600 flight hours after the 
effective date of this AD, and thereafter at intervals not to exceed 
600 flight hours, accomplish the procedures specified in paragraphs 
(a)(3)(i) and (a)(3)(ii) of this AD, on each:
    (i) Conduct a leak check of the dump valve and the service panel 
drain valve. The service panel drain valve leak check must be 
performed with a minimum of 3 PSID applied across the valve. Both 
the inner door/closure device and the outer cap/door must be leak 
checked.
    (ii) For service panel valves that have an inner seal: In lieu 
of pressure testing, the outer cap seal and seal surface may be 
visually inspected for damage or wear.
    (4) For other lavatory drain systems not addressed in paragraph 
(a)(1), (a)(2), or (a)(3) of this AD: Within 200 flight hours after 
the effective date of this AD, and thereafter at intervals not to 
exceed 200 flight hours, accomplish the procedures specified in 
paragraphs (a)(4)(i) and (a)(4)(ii) of this AD:
    (i) Conduct a leak check of the dump valve and the service panel 
drain valve. The service panel drain valve leak check must be 
performed with a minimum of 3 PSID applied across the valve. Both 
the inner door/closure device and the outer cap/door must be leak 
checked.
    (ii) For service panel valves that have an inner seal: In lieu 
of pressure testing, the outer cap seal and seal surface may be 
visually inspected for damage or wear.
    (5) For flush/fill lines: Within 5,000 flight hours after the 
effective date of this AD, and thereafter at intervals not to exceed 
5,000 flight hours, accomplish the procedures specified in either 
paragraph (a)(5)(i) or (a)(5)(ii) of this AD, as appropriate for the 
airplane's flush/fill line installation:
    (i) For airplanes equipped with a flush/fill line cap, 
accomplish either paragraph (a)(5)(i)(A) or (a)(5)(i)(B):
    (A) Conduct a leak check of the flush/fill line cap. This leak 
check must be made with a minimum of 3 PSID applied across the cap. 
Or
    (B) Replace the seals on the toilet tank anti-siphon (check) 
valve and in the flush/fill line cap. Additionally, perform a leak 
check of the toilet tank anti-siphon (check) valve with a minimum of 
3 PSID across the valve after changing the seals.
    (ii) For airplanes equipped with a check valve vacuum breaker, 
Monogram part number 4803-86 series: Replace the O-rings/seals in 
the valve and test the check valve and vacuum breaker sections of 
the valve for proper operation, in accordance with the 
manufacturer's component maintenance/overhaul manual.
    (6) As a result of the leak checks and inspections required by 
this paragraph, or if evidence of leakage is found at any other 
time, accomplish the requirements of either 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 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.

    Note 3: For purposes of this AD, ``leakage'' is defined as any 
visible leakage observed during a leak test; the presence of ice in 
the service panel; or horizontal fluid residue streaks or 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 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): Prior to further flight, drain the affected 
lavatory system and placard the lavatory inoperative until repairs 
can be accomplished.
    (b) As an alternative to the requirements of paragraph (a) of 
this AD: Within 180 days after the effective date of this AD, revise 
the FAA-approved maintenance program to include the requirements 
specified in paragraphs (b)(1), (b)(2), (b)(3), (b)(4), (b)(5), 
(b)(6), and (b)(7) of this AD:
    (1) Replace the valve seals in accordance with the applicable 
schedule specified in paragraphs (b)(1)(i) and (b)(1)(ii) of this 
AD. Any revision to this replacement schedule must be approved by 
the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, 
Transport Airplane Directorate.
    (i) For each lavatory drain system that has an in-line drain 
valve installed, Kaiser Electroprecision part number series 2651-
329: Replace the seals within 5,000 flight hours after revision of 
the maintenance program in accordance with paragraph (b) of this AD, 
and thereafter at intervals not to exceed 52 months.
    (ii) For each lavatory drain system that has any other type of 
drain valve: Replace the seals within 5,000 flight hours after 
revision of the maintenance program in accordance with paragraph (b) 
of this AD, and thereafter at intervals not to exceed 18 months.
    (2) Conduct periodic leak checks of the lavatory drain systems 
in accordance with the applicable schedule specified in paragraphs 
(b)(2)(i), (b)(2)(ii), (b)(2)(iii), and (b)(2)(iv) of this AD. If 
the individual waste drain system incorporates more than one type of 
valve, the interval that applies to that system is determined by the 
component with the longest inspection interval allowed. Each of the 
components in that system must be inspected/tested at that time. Any 
revision to this leak check schedule must be approved by the 
Manager, Los Angeles ACO, FAA, Transport Airplane Directorate.
    (i) For each lavatory drain system that has an in-line drain 
valve, Kaiser Electroprecision part number series 2651-329: Within 
5,000 flight hours after revision of the maintenance program in 
accordance with paragraph (b) of this AD, and thereafter at 
intervals not to exceed 24 months or 5,000 flight hours, whichever 
occurs later, accomplish the procedures specified in paragraphs 
(b)(2)(i)(A) and (b)(2)(i)(B) of this AD:
    (A) Conduct a leak check of the 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. The in-line drain valve leak 
check must be performed with a minimum of 3 PSID applied across the 
valve.
    (B) Visually inspect the service panel drain valve outer cap/
door seal and the inner seal (if the valve has an inner door/closure 
device with a second positive seal) and seal mating surface for wear 
or damage that may cause leakage. Any worn or damaged seal must be 
replaced and any damaged seal mating surface must be repaired or 
replaced, prior to further flight, in accordance with the valve 
manufacturer's maintenance manual.
    (ii) Within 1,000 flight hours after revising the maintenance 
program in accordance with paragraph (b) of this AD, and thereafter 
at intervals not to exceed 1,000 flight hours, accomplish the 
procedures specified in paragraphs (b)(2)(ii)(A) and (b)(2)(ii)(B) 
of this AD for each lavatory drain system that has a service panel 
drain valve installed that is listed in Table 2 of this AD:

                      Table 2.--Valves Requiring Leak Checks at 1,000-Flight Hour Intervals                     
----------------------------------------------------------------------------------------------------------------
               Manufacturer                          Part No.                          Serial No.               
----------------------------------------------------------------------------------------------------------------
Shaw Aero Devices........................  10101000C..................  All serial numbers.                     
Shaw Aero Devices........................  10101000B..................  All serial numbers.                     
Shaw Aero Devices........................  331 series.................  All serial numbers.                     
Shaw Aero Devices........................  332 series.................  All serial numbers.                     
Pneudraulics.............................  9527 series................  All serial numbers.                     
----------------------------------------------------------------------------------------------------------------


[[Page 57310]]

    (A) Conduct leak checks of the dump valve and the service panel 
drain valve. The service panel drain valve leak check must be 
performed with a minimum of 3 PSID applied across the valve. Only 
the inner door/closure device of the service panel drain valve must 
be leak checked.
    (B) Visually inspect the service panel drain valve outer cap/
door seal and seal mating surface for wear or damage that may cause 
leakage.
    (iii) For each lavatory drain system that has a lavatory drain 
system valve that incorporates only an outer cap seal (i.e., uses no 
inner flapper), or that incorporates an inner seal that is not an 
attached part of the valve (i.e., a ``donut''): Within 200 flight 
hours after revising the maintenance program in accordance with 
paragraph (b) of this AD, and thereafter at intervals not to exceed 
200 flight hours, conduct leak checks of the dump valve and the 
service panel drain valve. The service panel drain valve leak check 
must be performed with a minimum 3 PSID applied across the valve. 
Both the donut and the outer cap/door must be leak checked.
    (iv) For each lavatory drain system that incorporates any other 
type of approved valve(s): Within 400 flight hours after revising 
the maintenance program in accordance with paragraph (b) of this AD, 
and thereafter at intervals not to exceed 400 flight hours, 
accomplish the procedures specified in paragraphs (b)(2)(iv)(A) and 
(b)(2)(iv)(B) of this AD:
    (A) Conduct leak checks of the dump valve and the service panel 
drain valve. The service panel drain valve leak check must be 
performed with a minimum 3 PSID applied across the valve. If the 
service panel drain valve has an inner door/closure device with a 
second positive seal, only the inner door must be leak checked.
    (B) If the valve has an inner door/closure device with a second 
positive seal: Visually inspect the service panel drain valve outer 
door/cap seal 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, and thereafter at intervals not to exceed 
5,000 flight hours, accomplish the procedures specified in either 
paragraph (b)(3)(i) or (b)(3)(ii) of this AD, as applicable:
    (i) For airplanes equipped with a flush/fill line cap, 
accomplish either paragraph (b)(3)(i)(A) or (b)(3)(i)(B):
    (A) Conduct a leak check of the flush/fill line cap. This leak 
check must be made with a minimum of 3 PSID applied across the cap. 
Or
    (B) Replace the seals on the toilet tank anti-siphon (check) 
valve and the flush/fill line cap. Additionally, perform a leak 
check of the toilet tank anti-siphon (check) valve with a minimum of 
3 PSID across the valve after changing the seals.
    (ii) For airplanes equipped with a check valve vacuum breaker, 
Monogram part number 4803-86 series: Replace the O-rings/seals in 
the valve and test the check valve and vacuum breaker sections of 
the valve for proper operation, in accordance with the 
manufacturer's component maintenance/overhaul manual.
    (4) Provide procedures for accomplishing visual inspections to 
detect leakage of the lavatory waste drain line and lavatory flush/
fill line, at each waste service panel, to be conducted by 
maintenance personnel at intervals not to exceed 4 calendar days or 
45 flight hours, whichever 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.
    (i) For systems incorporating an in-line drain valve, Kaiser 
Electroprecision part number series 2651-329: The reporting 
procedures must include provisions for reporting to maintenance any 
instances of abnormal operation of the valve handle for the in-line 
drain valve, as observed by service personnel during normal 
servicing.
    (A) Additionally, for these systems, these provisions must 
include procedures for either: Prior to further flight, following 
the in-line drain valve manufacturer's recommended troubleshooting 
procedures and correction of the discrepancy; or prior to further 
flight, draining the lavatory system and placarding it inoperative 
until the correction of the discrepancy can be accomplished.
    (B) If the drain system also includes an additional service 
panel drain valve, Shaw Aero Devices part number 10101000C-A (or 
higher dash number); or Shaw Aero Devices part number 10101000B-A 
(or higher dash number); or Shaw Aero Devices part number 10101B-
577-1 or 10101B-577-2; or Pneudraulics part number series 9527: 
Indications of abnormal operation of the valve handle for the in-
line drain valve need not be addressed immediately if a leak check 
of the service panel drain valve indicates no leakage or other 
discrepancy. In these cases, repair of the in-line drain valve must 
be accomplished within 1,000 flight hours after the leak check of 
the additional service panel drain valve.
    (6) Provide training programs for maintenance and servicing 
personnel that include information on ``Blue Ice Awareness'' and the 
hazards of ``blue ice.''
    (7) As a result of the leak checks and inspections required by 
this paragraph, or if evidence of leakage is found at any other 
time, accomplish the requirements of either paragraph (b)(7)(i), 
(b)(7)(ii) or (b)(7)(iii), as applicable:
    (i) If a leak is discovered, prior to further flight, repair the 
leak. Prior to further flight after repair, perform the leak test. 
Additionally, prior to returning the airplane to service, clean the 
surfaces adjacent to where the leakage occurred to clear them or 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 4: For purposes of this AD, ``leakage'' is defined as any 
visible leakage observed during a leak test; 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 in accordance with the valve manufacturer's maintenance 
manual.
    (iii) In lieu of performing the requirements of paragraph 
(b)(7)(i) or (b)(7)(ii): Prior to further flight, drain the affected 
lavatory system and placard the lavatory inoperative until repairs 
can be accomplished.
    (c) For operators who elect to comply with paragraph (b) of this 
AD: Any revision to (i.e., extension of) the leak check intervals 
required by paragraph (b) of this AD must be approved by the 
Manager, Los Angeles ACO, FAA, Transport Airplane Directorate. 
Requests for such revisions must be submitted to the Manager of the 
Los Angeles 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 check interval;
    (6) Whether or not seals have been replaced between the seal 
replacement intervals required by this AD;
    (7) Whether or not leakage has been detected between leak check 
intervals required by this AD, and the reason for leakage (i.e., 
worn seals, foreign materials on sealing surface, scratched or 
damaged sealing surface or valve, etc.); and
    (8) Whether or not any leak check was conducted without first 
inspecting or cleaning the sealing surfaces, changing the seals, or 
repairing the valve. [If such activities have been accomplished 
prior to conducting the periodic leak check, that leak check 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 (b)(1) of this 
AD. Performing this scheduled seal change immediately prior to a 
leak check will not cause that leak check to be recorded as a 
failure.] The leak check is meant to be performed with the valve in 
the condition it would be in when in normal service. Only major 
blockages need be removed prior to a leak check. Minor debris that 
is not commonly removed during normal ground maintenance should not 
be removed prior to the leak check.

    Note 5: Requests for approval of revised leak check intervals 
may be submitted in any format, provided that the data give the same 
level of detail specified in paragraph (c) of this AD.
    Note 6: For the purposes of expediting resolution of requests 
for revisions to the leak check 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 check interval.


[[Page 57311]]


    (d) For all airplanes: Within 5,000 flight hours after the 
effective date of this AD, accomplish the requirements of either 
paragraph (d)(1) or (d)(2) of this AD:
    (1) Install a lever/lock cap on the flush/fill lines at each 
lavatory service panel. The cap must be either an FAA-approved 
lever/lock cap, or a cap installed in accordance with McDonnell 
Douglas DC-9 Service Bulletin 38-47, dated April 17, 1992. Or
    (2) Install a Monogram 4803-86 series check valve on the flush/
fill lines for all lavatory service panels.
    (e) For only those airplanes listed in McDonnell Douglas DC-9 
Service Bulletin 38-41, Revision 3, dated July 5, 1994: Accomplish 
the procedures specified in paragraphs (e)(1) and (e)(2) of this AD:
    (1) Conduct leak checks of the lavatory vent system at the same 
time as conducting the leak checks of the dump valve and flush/fill 
line required by this AD. If a leak is discovered, prior to further 
flight, accomplish the procedures specified in either paragraph 
(e)(1)(i), (e)(1)(ii), (e)(1)(iii), or (e)(1)(iv) of this AD:

    Note 7: The leak check of the lavatory vent system should be 
performed with a minimum of 3 pounds per square inch differential 
pressure (PSID) across the vent system. This leak check may be 
performed by filling the toilet tank with water/rinsing fluid to a 
level at least 4 inches above the flapper in the bowl, and checking 
for leakage after a period of 5 minutes. (These are the same 
procedures to be used for performing the leak checks of the dump 
valve and flush/fill line.)

    (i) Repair the leak and retest. Or
    (ii) Drain the affected lavatory system and placard the lavatory 
inoperative until repairs can be accomplished. Or
    (iii) Install an FAA-approved modification that deactivates the 
vent system. After accomplishment of this deactivation, the leak 
checks of the lavatory vent system may be discontinued. Or
    (iv) Replace/modify the vent system in accordance with McDonnell 
Douglas DC-9 Service Bulletin 38-41, Revision 3, dated July 5, 1994. 
After accomplishment of this replacement/modification, the leak 
checks of the lavatory vent system may be discontinued.
    (2) Within 3 years after the effective date of this AD: Either 
replace/modify the vent system in accordance with McDonnell Douglas 
DC-9 Service Bulletin 38-41, Revision 3, dated July 5, 1994; or 
install an FAA-approved modification that deactivates the vent 
system. Accomplishment of either of these actions constitutes 
terminating action for the leak checks of the lavatory vent system 
that are required by this AD.
    (f) 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 checks required by this AD shall be 
established in accordance with either paragraph (f)(1) or (f)(2) of 
this AD, as applicable. After each leak check has been performed 
once, each subsequent leak check must be performed in accordance 
with the new operator's schedule, in accordance with either 
paragraph (a) or (b) of this AD, as applicable.
    (1) For airplanes previously maintained in accordance with this 
AD: The first leak check to be performed by the new operator must be 
accomplished in accordance with either the previous operator's 
schedule or the new operator's schedule, whichever would result in 
the earlier accomplishment date for that leak check.
    (2) For airplanes that have not been previously maintained in 
accordance with this AD: The first leak check to be performed by 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.
    (g) 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, Los Angeles ACO, FAA, Transport 
Airplane Directorate. Operators shall submit their requests through 
an appropriate FAA PMI, who may add comments and then send it to the 
Manager, Los Angeles ACO.

    Note 8: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.
    Note 9: For any valve that is not eligible for the extended leak 
check intervals of this AD: To be eligible for the leak check 
interval specified in paragraph (a)(1), (a)(2), (b)(2)(i), or 
(b)(2)(ii), the service history data of the valve must be submitted 
to the Manager, Los Angeles ACO, FAA, Transport Airplane 
Directorate, with a request for approval of an alternative method of 
compliance with this AD. 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. Additionally, the request 
should include 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, including a winter season, collected in accordance 
with the requirements of paragraph (c) of this AD or a similar 
program. The configuration of the entire drain system on the 
airplanes used in evaluating a drain valve leak check interval 
should be defined in the request so as to ensure that the drain 
system is representative of the applications where the valve will be 
used. As an example, data collected on a panel valve installed below 
a ball valve would not be acceptable for substantiating a leak check 
interval for the panel valve, since an installation below a ball 
valve would not be representative of the normal applications where 
it could be used.

    (h) 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.
    (i) The actions shall be done in accordance with McDonnell 
Douglas DC-9 Service Bulletin 38-47, dated April 17, 1992; and 
McDonnell Douglas DC-9 Service Bulletin 38-41, Revision 3, dated 
July 5, 1994. 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 McDonnell Douglas 
Corporation, 3855 Lakewood Boulevard, Long Beach, California 90846, 
Attention: Technical Publications Business Administration, 
Department C1-L51 (2-60). Copies may be inspected at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; or at the FAA, Transport Airplane Directorate, Los 
Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC.
    (j) This amendment becomes effective on December 11, 1996.

    Issued in Renton, Washington, on October 18, 1996.

James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-27395 Filed 11-5-96; 8:45 am]
BILLING CODE 4910-13-U