[Federal Register Volume 60, Number 247 (Tuesday, December 26, 1995)]
[Proposed Rules]
[Pages 66764-66770]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-31245]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-214-AD]


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to all McDonnell Douglas DC-9 and DC-
9-80 series airplanes, and Model MD-88 airplanes. Among other things, 
this proposal would require repetitive leak checks of the lavatory 
drain system and repair, if necessary; would provide for the option of 
revising the FAA-approved maintenance program to include a schedule of 
leak checks; would require the installation of a cap on the flush/fill 
line; and would require replacement or modification of the vent system 
piping. This proposal 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 proposed AD are intended to prevent such damage 
associated with the problems of ``blue ice.''

DATES: Comments must be received by March 28, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-214-AD, 1601 Lind Avenue SW., Renton, 
Washington 98055-4056. Comments may be inspected at this location 
between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal 
holidays.
    The service information referenced in the proposed rule 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 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.

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:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 95-NM-214-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules 
Docket No. 95-NM-214-AD, 1601 Lind Avenue SW., Renton, Washington 
98055-4056. 

[[Page 66765]]


Discussion

    Over the past ten years, the FAA has received numerous reports of 
leakage of waste fluid from the lavatory service systems on in-service 
transport category airplanes. This leakage has resulted in the 
formation of ``blue ice'' on the fuselage. In some instances, the 
``blue ice'' has subsequently dislodged from the fuselage and has been 
ingested into an engine. In several of these incidents, the ingestion 
of ``blue ice'' into an engine resulted in the loss of an engine fan 
blade, severe engine damage, and the in-flight shutdown of the engine. 
In two cases, the loads created by the ``blue ice'' being ingested into 
the engine resulted in the engine being physically torn from the 
airplane. Damage to an engine, or the separation of an engine from the 
airplane, could result in reduced controllability of the airplane.
    The FAA also has received reports of at least three incidents of 
damage to the airframe of transport category airplanes caused by 
foreign objects and ``blue ice,'' resulting from leakage of the forward 
toilet drain valve and flush/fill line, striking the airframe. One 
report was of a dent on the leading edge of the right horizontal 
stabilizer on a Boeing Model 737 series airplane that was caused by 
``blue ice'' that had formed from leakage through a flush/fill line; in 
this case, the flush/fill cap was missing from the line at the forward 
service panel. Numerous operators have stated that leakage from the 
flush/fill line is a significant source of problems associated with 
``blue ice.'' Such damage caused by ``blue ice'' could adversely affect 
the integrity of the fuselage skin or surface structures.
    Additionally, there have been numerous reports of ``blue ice'' 
dislodging from airplanes and striking houses, cars, buildings, and 
other occupied areas on the ground. Although there have been no reports 
of any person being struck by ``blue ice,'' the FAA considers that the 
large number of reported cases of ``blue ice'' falling from the 
lavatory drain system is sufficient to support the conclusion that 
``blue ice'' presents an unsafe condition to people on the ground. 
Demographic studies have shown that population density has increased 
around airports, and probably will continue to increase. These are 
populations that are at greatest risk of injury and damage due to 
``blue ice'' dislodging from an airplane during the airplane's descent 
into the airport. Without actions to ensure that leaks from the 
lavatory drain systems are detected and corrected in a timely manner, 
``blue ice'' incidents could go unchecked and eventually someone may be 
struck, perhaps fatally, by falling ``blue ice.''

Current Rules

    In response to these incidents, the FAA has issued several AD's 
applicable to various transport category airplanes:
    1. AD 86-05-07, Amendment 39-5250 (51 FR 7767, March 6, 1986): 
Issued on February 26, 1986, this AD required periodic leak checks of 
all Boeing Model 727 aircraft forward lavatory drain systems (both dump 
valve and drain valve) at intervals not to exceed 15 months, and 
corrective action, if necessary.
    2. AD 94-23-10, amendment 39-9073 (59 FR 59124, November 16, 1994): 
Issued on November 9, 1994, this AD supersedes AD 86-05-07. It 
continues to require various leak checks of Boeing Model 727 series 
airplanes, but adds requirements for leak checks of other lavatory 
drain systems; 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 either a 
periodic leak check of the flush/fill line cap or replacement of the 
seals on both that cap and the toilet tank anti-siphon (check) valve.
    3. AD 89-11-03, amendment 39-6223 (54 FR 21933, May 22, 1989): 
Issued on May 9, 1989, this AD is applicable to certain Boeing Model 
737-300 and -400 airplanes. It requires repetitive leak checks of the 
forward lavatory service system at intervals of 200 hours time-in-
service, and repair, if necessary. That AD also provided operators with 
an optional action in lieu of performing these periodic checks, which 
entails draining the system, locking the lavatory, and placarding the 
lavatory inoperative.
    4. The FAA is planning to amend AD 89-11-03 to make it applicable 
to all Boeing Model 737 series airplanes, and to require additional 
inspections and other actions similar to those of AD 94-23-10.
    5. The FAA is currently considering additional rulemaking to 
address the problems associated with ``blue ice'' on various other 
transport category airplanes, including those manufactured by Airbus, 
British Aerospace, Fokker, and Lockheed, as well as other models 
manufactured by McDonnell Douglas.

Description of Relevant Service Information

    The FAA has reviewed and approved McDonnell Douglas DC-9 Service 
Bulletin 38-47, dated April 17, 1992, which describes procedures for 
installing a lever lock rinse cap on lavatory service panels. The 
development of this installation was in response to reports that the 
quarter-turn caps, which are normally installed on the fill/rinse line 
at the lavatory service panel, are often removed by ground service 
personnel or are not properly re-installed and reseated after 
servicing. Installation of lever lock rinse caps in place of quarter-
turn caps will inhibit the closing of the service panel doors when the 
cap is not properly closed; this will enable service personnel to 
recognize situations when the cap needs to be closed correctly. This, 
in turn, will minimize the possibility of leakage of lavatory waste 
liquids from the cap and the subsequent formation of ``blue ice.''
    The FAA also has reviewed and approved McDonnell Douglas DC-9 
Service Bulletin 38-41, Revision 3, dated July 5, 1994, which describes 
procedures for modifying and replacing the lavatory vent system piping. 
The development of this modification was in response to reports of 
``blue ice'' build-up at the lavatory overboard vent on four Model DC-9 
series airplanes. The ice build-up was attributed to lavatory waste 
tanks exceeding their capacity and overflowing through the overboard 
vent piping. This build-up of ``blue ice'' can break loose and damage 
either the nose cowl of engine No. 1 or the engine itself. The modified 
vent system piping minimizes the possibility of waste water siphoning 
overboard.

Description of the Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the FAA is 
proposing an AD that would require the following actions:
    Paragraph (a) of the proposed AD would require repetitive leak 
checks of the lavatory dump valve, drain valve (either service panel or 
in-line drain valve), and lavatory vent system. The intervals for 
performing these leak checks would vary from 200 flight hours to 1,500 
flight hours, depending upon what type of valve is installed at each 
location. The leak check of panel valves would be required to be 
performed with a minimum of 3 pounds per square inch differential 
pressure (PSID) applied across the valve. If any leak is discovered 
during the leak checks, operators would be required either to repair 
the leak and retest it, or drain the lavatory system and placard it 
inoperative until repairs can be made.
    In cases where the panel valve has an inner seal, in lieu of 
pressure testing, operators are provided with the option of performing 
a visual inspection for damage or wear of the outer cap seal 

[[Page 66766]]
and seal surface. Any damaged parts detected would be required to be 
repaired or replaced prior to further flight, or the lavatory drained 
and placarded inoperative until repairs can be made.
    Additionally, the flush/fill line cap would be required to be leak 
checked. In lieu of this particular check, operators may elect to 
replace the seals on the toilet tank anti-siphon (check) valve and 
flush/fill line cap.
    Paragraph (b) of this proposed AD would provide an optional 
procedure for complying with the rule, which would entail revising the 
FAA-approved maintenance program to incorporate a schedule to conduct 
leak checks of the lavatory drain systems. The maintenance program 
change would also require that procedures be provided for accomplishing 
the visual inspections to detect leakage, and for reporting leakage. 
Additionally, a training program must be provided to maintenance and 
servicing personnel, which would include information on ``blue ice'' 
awareness and the hazards of ``blue ice.''
    Operators electing to comply with this option would be required to 
obtain approval from the Manager of the FAA's Los Angeles Aircraft 
Certification Office (ACO) for any revision to the leak check 
intervals. Requests for such revisions would be required to be 
accompanied by certain data when submitted to the ACO [through the 
appropriate FAA Principal Maintenance Inspector (PMI)] for approval. In 
paragraph (c) of the proposed rule, the FAA proposes a ``data 
collection format'' for these requests. Data submitted in accordance 
with the proposed format, if favorable to an increase in the leak check 
interval, will allow the FAA to justify increasing the leak check 
interval with assurance that the valves involved have the required 
reliability. The data provided also will be important in assisting the 
FAA in making future determinations of appropriate leak check intervals 
for new valves that have shown promising, but not conclusive, service 
data. For example, the FAA has previously approved extension of the 
leak check interval to 2,000 hours for one operator using PneuDraulics 
part number series 9527 valves on Boeing Model 737 series airplanes. 
Assuming that this operator successfully completes two cycles of 2,000-
hour leak checks without finding leakage, the FAA may consider 
approving the extension of the 2,000-hour leak check interval to a 
4,000-hour interval for this operator.
    Paragraph (d) of the proposed AD also would require that all 
operators install a lever/lock cap on the flush/fill lines for all 
service panels. The cap must be either an FAA-approved cap or one 
installed in accordance with McDonnell Douglas Service Bulletin 38-47.
    Paragraph (e) of the AD would require that leak checks of the 
lavatory vent system be conducted on certain airplanes at the same time 
as the leak checks of the dump valve and flush/fill line are conducted. 
If a leak is detected, the proposed rule would provide for several 
optional corrective actions that operators could accomplish.
    Paragraph (e) would also require that, within 3 years, operators of 
certain airplanes either replace/modify the lavatory vent system piping 
in accordance with McDonnell Douglas DC-9 Service Bulletin 38-41, 
Revision 3; or install an FAA-approved modification that deactivates 
the vent system. Once either of these actions is accomplished, the 
periodic leak checks of the lavatory vent system may be discontinued.
    Paragraph (f) of the proposed AD would require that, before an 
operator places an airplane subject to the AD into service, the 
operator must establish a schedule for accomplishment of the subject 
leak checks. This provision is intended to ensure that transferred 
airplanes are inspected in accordance with the AD on the same basis as 
if there were continuity in ownership, and that scheduling of the leak 
checks for each airplane is not delayed or postponed due to a transfer 
of ownership. Airplanes that have previously been subject to the AD 
would have to be checked in accordance with either the previous 
operator's or the new operator's schedule, whichever would result in 
the earlier accomplishment date for that leak check. Other airplanes 
would have to be inspected before an operator could begin operating 
them or in accordance with a schedule approved by the FAA PMI, but 
within a period not exceeding 200 flight hours.

Economic 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, would be affected by this proposed AD.
    1. Leak checks. It would 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 proposed 
leak check requirement on U.S. operators would 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 would 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 proposed inspection requirement on U.S. 
operators would be between $120 and $1,800 per airplane per year.
    3. Installation of cap on flush/fill line. The proposed 
installation would 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 would 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 would 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 proposed 
installation on U.S. operators would be between $203 and $2,361 per 
airplane.
    The portion of this installation that entails modification of 
lavatory vent lines would 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 proposed 
installation on U.S. operators would 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 proposed in 

[[Page 66767]]
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 would 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 would 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 proposed maintenance 
revision requirement of this AD on U.S. operators is estimated to be 
$2,400 per operator.
    The ``cost impact'' figures discussed above are based on 
assumptions that no operator has yet accomplished any of the proposed 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted.
    The FAA recognizes that the obligation to maintain aircraft in an 
airworthy condition is vital, but sometimes expensive. Because AD's 
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 
proposed 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 proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) Is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting 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.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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 USC 106(g), 40101, 40113, 44701.


Sec. 39.13  [Amended]

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

McDonnell Douglas: 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; 
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 use the authority 
provided in paragraph (g) of this AD to request approval from the 
FAA. This approval may address either no action, if the current 
configuration eliminates the unsafe condition; or different actions 
necessary to address the unsafe condition described in this AD. Such 
a request should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

    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 and flush/fill 
line 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 1,500 flight hours after the effective date of this AD, 
and thereafter at intervals not to exceed 1,500 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) For each lavatory drain system that has a service panel 
drain valve installed, Shaw Aero Devices part number 10101000C-A (or 


[[Page 66768]]
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: 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 procedures specified in paragraphs (a)(2)(i) and (a)(2)(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.
    (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:
    (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:
    (i) 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
    (ii) 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.
    (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) For each lavatory drain system that has a service panel 
drain valve installed, Shaw Aero Devices part number series 
10101000C; or Shaw Aero Devices part number series 10101000B; or 
Pneudraulics part number series 9527: 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:
    (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 

[[Page 66769]]
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:
    (i) 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
    (ii) 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.
    (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.]

    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.

    (d) For all airplanes: Within 5,000 flight hours after the 
effective date of this AD, 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.
    (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:
    (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 

[[Page 66770]]
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 7: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.
    Note 8: 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.

    (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.

    Issued in Renton, Washington, on December 19, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-31245 Filed 12-22-95; 8:45 am]
BILLING CODE 4910-13-U