[Federal Register Volume 60, Number 212 (Thursday, November 2, 1995)]
[Proposed Rules]
[Pages 55668-55673]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-27073]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 95-NM-120-AD]
Airworthiness Directives; McDonnell Douglas Model DC-10 Series
Airplanes and Model MD-11F (Freighter) 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 Model DC-10 series airplanes
and MD-11F airplanes. Among other things, this proposal would require
repetitive leak checks of the lavatory drain system and repair, if
necessary; would provide for
[[Page 55669]]
the option of revising the FAA-approved maintenance program to include
a schedule of leak checks; and would require the installation of a cap
on the flush/fill line. 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 January 30, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-120-AD, 1601 Lind Avenue SW., Renton,
Washington 98055-4056. Comments may be inspected at this location
between 9 a.m. and 3 p.m., Monday through Friday, except Federal
holidays.
The service information referenced in this AD may be obtained from
McDonnell Douglas Corporation, 3855 Lakewood Boulevard, Long Beach,
California 90846, Attention: Technical Publications Business
Administration, Dept. 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, Los Angeles Aircraft Certification
Office, Transport Airplane Directorate, 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-120-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-120-AD, 1601 Lind Avenue SW., Renton, Washington
98055-4056.
Discussion
Over the past ten years, the FAA has received numerous reports of
leakage from the lavatory service systems on in-service transport
category airplanes that resulted in the formation of ``blue ice'' on
the fuselage. In some instances, the ``blue ice'' subsequently
dislodged from the fuselage and was ingested in to 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 caused by foreign objects from the forward
toilet drain valve and flush/fill line on transport category airplanes.
One report was of a dent on the right horizontal stabilizer leading
edge on a 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 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 damage and injury due to ``blue ice''
dislodging from an airplane during descent. 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 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
[[Page 55670]]
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 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.
Discussion 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 would require the following actions:
Paragraph (a) of the proposed AD would require repetitive leak
checks of the lavatory dump valve and drain valve (either service panel
or in-line drain valve). The intervals for performing these leak checks
would vary from 200 flight hours to 1,000 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 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 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, 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.
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 38-65
or 38-39.
Paragraph (e) 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 435 Model DC-10 series airplanes and Model
MD-11F airplanes of the affected design in the worldwide fleet. The FAA
estimates that 285 airplanes of U.S. registry, and 18 U.S. operators,
would be affected by this proposed AD.
For airplanes in the passenger configuration, the estimated costs
associated with the requirements of this proposed AD would be as
follows:
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 two drains per
airplane. Depending upon the type of valve installed and the flight
utilization rate of the airplane, airplanes could be required to be
inspected as few as 3 times per year or as many as 15 times per year.
Based on these figures, the total cost impact of the proposed leak
check requirement on U.S. operators would be between $1,440 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 2 work hours 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,
airplanes could be required to be inspected as few as 3 times per year
or as many as 15 times per year. Based on these figures, the total cost
impact of the proposed inspection requirement on U.S. operators would
be between $360 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 airplane. There are 8 flush/fill lines per
airplane. There currently are 175 passenger-configured airplanes of
U.S. registry that would be subject to this requirement. Based on these
figures, the total cost impact of the proposed installation requirement
on U.S. operators would be $553,000, or $3,160 per airplane.
For airplanes in the freighter configuration, the estimated costs
associated with the requirements of this proposed AD would be as
follows:
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 is one per airplane.
Depending upon the type of valve installed and the flight utilization
rate of the airplane, airplanes could be required to be inspected as
few as 3 times per year or as many as 15 times per year. Based on these
figures, the total cost impact of the proposed
[[Page 55671]]
leak check requirement on U.S. operators would be between $720 and
$3,600 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,
airplanes could be required to be inspected as few as 3 times per year
or as many as 15 times per year. Based on these figures, the total cost
impact of the proposed inspection requirement on U.S. operators would
be between $180 and $900 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 airplane. There is 1 flush/fill lines per
airplane. There currently are 110 freighter-configured airplanes of
U.S. registry that would be subject to this requirement. Based on these
figures, the total cost impact of the proposed installation requirement
on U.S. operators would be $43,450, or $395 per airplane.
The number of required work hours, as indicated above, is presented
as if the accomplishment of the actions proposed in this AD were to be
conducted as ``stand alone'' actions. However, in actual practice,
these actions could be accomplished coincidentally or in combination
with normally scheduled airplane inspections and other maintenance
program tasks. Therefore, the actual number of necessary ``additional''
work hours 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 total cost impact of the proposed
maintenance revision requirement of this AD on the 18 affected U.S.
operators is estimated to be $43,200, or $2,400 per operator.
The ``total 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 U.S.C. 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-120-AD.
Applicability: All Model DC-10 series airplanes and Model MD-11F
series airplanes, certificated in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the
requirements of this AD. For airplanes that have been modified,
altered, or repaired so that the performance of the requirements of
this AD is affected, the owner/operator must use the authority
provided in paragraph (f) 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 previously
accomplished.
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 toilet dump valve leak checks required by this AD
may be performed by filling the toilet tank with water/rinsing fluid
[[Page 55672]]
to a level such that the bowl is approximately half full (at least 2
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), and (a)(5) 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 a service panel
drain valve installed, Kaiser Electroprecision part number series
0218-0032; or Shaw Aero Devices part number 1010100C-N (or higher
dash number); or Shaw Aero Devices part number 1010100B-A-1, serial
numbers 0115 through 0121, 0146 through 0164, and -0180 and higher;
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 following procedures:
(i) Conduct a leak check of the dump valve and 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. Any damaged parts must be
replaced or repaired prior to further flight, or the affected
lavatory(s) must be drained and placarded inoperative until repairs
can be accomplished.
(2) For each lavatory drain system that has a service panel
drain valve installed, Kaiser Electroprecision part number series
0218-0026, or Shaw Aero Devices part number series 1010100C (except
as called out in paragraph (a)(1) above), or Shaw Aero Devices part
number 1010100B (except as called out in paragraph (a)(1) above):
Within 600 flight hours after the effective date of this AD, and
thereafter at intervals not to exceed 600 flight hours, accomplish
the following procedures:
(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 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. Any damaged parts must be
replaced or repaired prior to further flight, or the affected
lavatory(s) must be drained and placarded inoperative until repairs
can be accomplished.
(3) For each lavatory drain system not addressed in paragraph
(a)(1) or (a)(2) 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 following procedures:
(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 3 PSID applied across the valve. If the
service panel drain valve has an inner door with a second positive
seal, both the inner door 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. Any damaged parts must be
replaced or repaired prior to further flight, or the affected
lavatory(s) must be drained and placarded inoperative until repairs
can be accomplished.
(4) 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 either of the procedures specified in
paragraph (a)(4)(i) or (a)(4)(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.
Note 3: The Inspection/Check procedure specified in DC-10
Maintenance Manual, chapter 38-30-00, pages 601 and 602, dated June
1, 1993, may be referred to as guidance for the procedures required
by this paragraph.
(5) If a leak is discovered during any leak check required by
paragraph (a) of this AD, prior to further flight, accomplish either
of the procedures specified in paragraph (a)(5)(i) or (a)(5)(ii) 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.
(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), and
(b)(6) of this AD.
(1) For each lavatory drain system: 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, replace the valve seals. Any revision to this replacement
schedule must be approved by the Manager, Los Angeles Aircraft
Certification Office (ACO), FAA, Transport Airplane Directorate.
(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), and (b)(2)(iii) 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/tested at that time at each service
panel location. Any revision to the leak check schedule must be
approved by the Manager, Los Angeles ACO, FAA, Transport Airplane
Directorate.
(i) For each lavatory drain system that has a service panel
drain valve installed, Kaiser Electroprecision part number series
0218-0032, or Kaiser Electroprecision part number series 0218-0026,
or Shaw Aero Devices part number series 1010100C, or Shaw Aero
Devises part number series 1010100B, 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
both of the following procedures:
(A) Conduct leak checks of the dump valve and 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. And
(B) Visually inspect the service panel drain valve outer cap/
door 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 with a lavatory drain system
valve that either incorporates ``donut'' assemblies (or substitute
assemblies from another manufacturer) Kaiser Electroprecision part
number 4259-20 or 4259-31, or incorporates Kaiser Roylyn part number
2651-231 or 2651-259 : 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, accomplish
either one of the following procedures:
(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. Both the
donut and the outer cap/door must be leak checked.
(B) For service panel valves that have an inner seal: In lieu of
pressure testing, visually inspect the outer cap seal and seal
surface for damage or wear. Any damaged parts must be replaced or
repaired prior to further flight, or the affected lavatory(s) must
be drained and placarded inoperative until repairs can be
accomplished.
(iii) For each lavatory drain system that incorporates any other
type of approved valves: 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
both of the following procedures:
(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. And
(B) If the valve has an inner door/closure device with a second
positive seal: Visually inspect the service panel drain valve outer
[[Page 55673]]
door/cap 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.
(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 either of the following procedures:
(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.
Note 4: The Inspection/Check procedure specified in DC-10
Maintenance Manual, chapter 38-30-00, pages 601 and 602, dated June
1, 1993, may be referred to as guidance for the procedures required
by this paragraph.
(4) Provide procedures for accomplishing visual inspections to
detect leakage, to be conducted by maintenance personnel at
intervals not to exceed 4 calendar days or 45 flight hours, which
ever occurs later.
(5) Provide procedures for reporting leakage. These procedures
shall provide that any ``horizontal blue streak'' findings must be
reported to maintenance and that, prior to further flight, the
leaking system shall either be repaired, or be drained and placarded
inoperative.
(6) Provide training programs for maintenance and servicing
personnel that include information on ``Blue Ice Awareness'' and the
hazards of ``blue ice.''
(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.);
(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 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 assurance 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 for all lavatory service panels. The cap must be either
an FAA-approved lever/lock cap; or a lever/lock cap installed in
accordance with McDonnell Douglas Service Bulletin 38-65 (for Model
DC-10 series airplanes) or Service Bulletin 38-39 [for Model MD-11F
series airplanes (freighter)], as applicable.
(e) For any affected airplane acquired after the effective date
of this AD: Before any operator places into service any airplane
subject to the requirements of this AD, a schedule for the
accomplishment of the leak checks required by this AD shall be
established in accordance with either paragraph (e)(1) or (e)(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 the previous operator's schedule or
with 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.
(f) 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 paragraphs (a)(1) and (b)(2)(i), the service
history data of the valve must be submitted to the Manager, Los
Angeles ACO, FAA, Transport Airplane Directorate, with a request for
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.
(g) 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 October 26, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-27073 Filed 11-1-95; 8:45 am]
BILLING CODE 4910-13-U
