Airworthiness Directives; McDonnell Douglas Model DC-10 Series Airplanes and Model MD-11F (Freighter) Airplanes

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