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

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