[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
