62708 Federal Register / Vol. 62, No. 227 / Tuesday, November 25, 1997 / Proposed Rules

related to the disaster for which SBA

issued the original loan. For example, if

you discover hidden damage within a

reasonable time after SBA approved

your original disaster loan and before

repair, renovation, or reconstruction is

complete, you may request an increase.

Or, if applicable building code

requirements were changed since SBA

approved your original loan, you may

request an increase in your loan

amount.

§ 123.19 Can I request an increase in the

amount of an economic injury loan?

SBA will consider your request for an

increase in the loan amount if you can

show that the increase is essential for

your business to continue and is based

on events occurring after SBA approved

your original loan which were beyond

your control. For example, delays may

have occurred beyond your control

which prevent you from resuming your

normal business activity in a reasonable

time frame. Your request for an increase

in the loan amount must be related to

the disaster for which the SBA

economic injury disaster loan was

originally made.

§ 123.20 How long do I have to request an

increase in the amount of a physical

disaster loan or an economic injury loan?

You should request a loan increase as

soon as possible after you discover the

need for the increase, but not later than

two years after SBA approved your

physical disaster or economic injury

loan. After two years, the SBA Associate

Administrator for Disaster Assistance

(AA/DA) may waive this limitation after

finding extraordinary and unforeseeable

circumstances.

Dated: November 14, 1997.

Aida Alvarez,

Administrator.

[FR Doc. 97–30847 Filed 11–24–97; 8:45 am]

BILLING CODE 8025–01–P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95–NM–111–AD]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 737–100, –200, –300, –400, and

–500 Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Supplemental notice of

proposed rulemaking; reopening of

comment period.

SUMMARY: This document revises an

earlier proposed airworthiness directive

(AD), applicable to all Boeing Model

737–100, –200, –300, –400, and –500

series airplanes, which would have

superseded an existing AD that

currently requires either leak tests of the

forward lavatory service system, and

repair, as necessary; or draining the

system and placarding the lavatory

inoperative. That proposed AD would

have provided an option for

accomplishing terminating action for

certain leak tests. It would have

required leak tests of other lavatory

drain systems; installation of a cap or

vacuum break on the flush/fill line; and

either periodic replacement of the seal

for the cap and tank anti-siphon valve

or periodic maintenance of the vacuum

break in the flush/fill line. This action

revises the proposed AD by removing

the terminating action; requiring

periodic changing of the seals of certain

lavatory drain systems; replacing

‘‘donut valves’’ with other FAAapproved valves; revising certain leak

test intervals; and revising the

pressurization and fluid level

requirements for testing. The actions

specified by this proposed AD are

intended to prevent damage to engines,

airframes, and property on the ground

that is associated with the problems of

‘‘blue ice’’ that forms from leaking

lavatory drain systems on transport

category airplanes and subsequently

dislodges from the airplane fuselage.

DATES: Comments must be received by

January 5, 1998.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 95–NM–

111–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

Boeing Commercial Airplane Group,

P.O. Box 3707, Seattle, Washington

98124–2207. This information may be

examined at the FAA, Transport

Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Don

Eiford, Aerospace Engineer, Systems

and Equipment Branch, ANM–130S,

FAA, Seattle Aircraft Certification

Office, 1601 Lind Avenue, SW., Renton,

Washington; telephone (425) 227–2788;

fax (425) 227–1181.

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–111–AD.’’ The

postcard will be date stamped and

returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this

supplemental NPRM by submitting a

request to the FAA, Transport Airplane

Directorate, ANM–103, Attention: Rules

Docket No. 95–NM–111–AD, 1601 Lind

Avenue, SW., Renton, Washington

98055–4056.

Discussion

A proposal to amend part 39 of the

Federal Aviation Regulations (14 CFR

part 39) to add an airworthiness

directive (AD), applicable to all Boeing

Model 737–100, –200, –300, –400, and

–500 series airplanes, was published as

a notice of proposed rulemaking

(NPRM) in the Federal Register on

November 2, 1995 (60 FR 55673). That

NPRM proposed to supersede AD 89–

11–03, amendment 39–6223 (54 FR

21933, May 22, 1989), applicable to

certain Boeing Model 737–300 and –400

series airplanes. That proposal would

have continued to require either

repetitive leak tests on the forward

lavatory service system, and repair, as

necessary; or draining of the system and

placarding the lavatory inoperative. It

would have also added a requirement to
Federal Register / Vol. 62, No. 227 / Tuesday, November 25, 1997 / Proposed Rules 62709

perform leak tests of other lavatory

drain systems; provided for the option

of revising the FAA-approved

maintenance program to include a

schedule of leak tests; required the

installation of a cap or vacuum break on

the flush/fill line; and required either a

periodic replacement of the seal for the

cap and tank anti-siphon valve or

periodic maintenance of the vacuum

break in the flush/fill line. That

proposal also would have expanded the

applicability of the rule to include all

Model 737 series airplanes.

That NPRM was 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. Such formation and

dislodging of ‘‘blue ice,’’ if not

corrected, could result in damage to the

engine and potential separation of the

engine from the airplane.

Actions Since the Issuance of Previous

NPRM

Since the issuance of that previous

NPRM, the FAA has received reports

indicating that leakage of certain in-line

valves of the lavatory waste drain

systems has been detected. In

consideration of this and other factors (a

more detailed discussion of the other

factors is presented later in this

supplemental NPRM), the FAA has

determined that the terminating action

provided by the previous NPRM must

be removed from this supplemental

NPRM. In addition, the FAA has

determined that certain additional

changes to the previous NPRM are

necessary.

Related AD’s

On November 9, 1994, the FAA issued

AD 94–23–10, amendment 39–9073 (59

FR 59124, November 16, 1994), which is

applicable to Boeing Model 727 series

airplanes. That AD contains numerous

requirements that are similar to those

proposed in this action, which is

applicable to Model 737 series

airplanes. In fact, several of the

proposed requirements of this action are

based on alternative methods of

compliance that the FAA had approved

previously for compliance with AD 94–

23–10.

The FAA is currently considering

additional rulemaking to address the

problems associated with ‘‘blue ice’’ on

other transport category airplanes.

General Changes to the Proposal:

Revision of Optional Maintenance

Program

As discussed previously, the FAA has

received recent reports of leakage in

certain in-line drain (ball) valves. In

order to ensure that leak check results

are uniformly reviewed before any

extension of leak check intervals, the

FAA has determined that the previously

proposed optional terminating action

provided for in paragraph (b) of the

previous NPRM must be removed from

this supplemental NPRM in order to

maintain an adequate level of safety.

The 5,000-hour leak test interval

remains unchanged.

General Changes to the Proposal:

Revised Leak Test Intervals for Certain

Valves

Based on recently received new data

submitted by various operators, the

supplemental NPRM would revise the

previously proposed leak test intervals

for certain valves. These changes have

been added to paragraphs (a) and (b) of

this supplemental NPRM. (A more

detailed discussion of those proposed

changes in the leak test intervals is

presented later in the preamble.)

General Changes to the Proposal:

Requirement To Change Seals

One comment submitted to the Rules

Docket in response to the previously

issued NPRM, requests that a

requirement to change the valve seals be

added to paragraph (a) of the proposal.

The commenter points out that if the

seals are not changed periodically, they

could fail and leak in between leak

testing. The FAA concurs with the

request, and has added a requirement to

paragraph (a) of this supplemental

NPRM to change the seals of valves at

intervals similar to the proposed

requirements of the valve seal changes

in paragraph (b) of this supplemental

NPRM.

General Changes to the Proposal:

Requirement To Remove ‘‘Donut’’

Valves

Another comment submitted to the

Rules Docket in response to the

previously issued NPRM, requests that

the FAA mandate the removal of

‘‘donut’’ style valves from the airplane

and require replacement with one of the

three service panel valves, as specified

in the proposed rule. The commenter

states that the ‘‘donut’’ valves have a

long history of poor performance.

The FAA concurs that the ‘‘donut’’

style valves should be removed.

‘‘Donut’’ style valves have been

involved in more cases of leakage and

consequent formation of ‘‘blue ice’’ than

any other valve design. In addition,

cases of leakage of ‘‘donut’’ style valves

that have been leak tested (as required

by previous AD’s) are still being

reported. Therefore, the FAA has

determined that the ‘‘donut’’ style

valves should be removed.

However, the FAA finds that, rather

than require replacement of the ‘‘donut’’

style valves with one of the three service

panel valves listed in the previous

NPRM, a requirement to replace the

‘‘donut’’ valves with ‘‘an FAA-approved

valve’’ is more appropriate. This leaves

an opportunity for operators to choose

valves that may be ‘‘FAA-approved,’’

but that may not be specified in the rule.

Paragraphs (a)(6)(iii) and (b)(2)(iv)(C) of

this supplemental NPRM have been

revised to reflect this change.

General Changes to the Proposal:

Revised Pressurization Requirements

Several comments submitted to the

Rules Docket in response to the

previously issued NPRM included

requests to revise the requirement to

pressurize the airplane while

performing leak tests to verify the

integrity of in-line drain valves or

service panel drain valves. The

commenters state that applying a

minimum pressure of 3 pounds per

square inch differential pressure (PSID)

across the line by using a leak test tool,

such as a hand-held vacuum pump,

would be just as effective as

pressurizing the airplane, yet would

provide a more economical method of

accomplishing the leak test.

Additionally, the commenters point out

that using a 3 PSID differential pressure

is consistent with the ‘‘blue ice’’ AD

requirements for Boeing Model 727

series airplanes.

The FAA concurs. Paragraphs (a) and

(b) of this supplemental NPRM have

been revised to require the tests while

applying a minimum 3 PSID differential

pressure in the same direction as would

occur during flight.

General Changes to the Proposal:

Revised Requirement of Fluid Level

Several comments submitted to the

Rules Docket in response to the

previously issued NPRM included

requests that the FAA revise the

proposed leak test procedure to empty

and refill the lavatory to within two

inches of overflowing. The commenters

state that the difference between that

specified level of fluid and actual

overflowing of the fluid is

approximately only one gallon. Since

overflow of the lavatory could cause

damage to the airplane, the commenters

consider that any fluid above normal

level (10 gallons) is unnecessary.
62710 Federal Register / Vol. 62, No. 227 / Tuesday, November 25, 1997 / Proposed Rules

Therefore, the commenters request that

the required fluid level be reduced.

The FAA concurs that a lower fluid

level is acceptable, except in the case of

testing the anti-siphon valve. The FAA

finds that fluid at the 10-gallon level is

too low to result in fluid contacting the

seals during the test of the anti-siphon

valve; the lack of contact of the fluid

with the seals would invalidate the test.

Therefore, this supplemental NPRM has

been revised to require that the lavatory

be filled with a minimum of 10 gallons

of fluid, except when testing the antisiphon valve. However, operators

should take precautions to ensure that

the tank is not overfilled; a statement to

this effect has been added to this

supplemental NPRM.

Conclusion

Since the changes described above

expand the scope of the previously

issued proposed rule, the FAA has

determined that it is necessary to reopen

the comment period to provide

additional opportunity for public

comment.

Comments Received

Due consideration has been given to

the comments received in response to

the NPRM issued previously.

Support for the Proposal

One commenter supports the

proposed rule.

Request To Withdraw the Proposal:

Risk of Injury From ‘‘Blue Ice’’ Is

Extremely Remote

The Air Transport Association (ATA)

of America, on behalf of its members,

requests that the proposed rule be

withdrawn. The commenter considers

that, from a statistical standpoint, the

risk of injury to persons on the ground

from falling ‘‘blue ice’’ is extremely

remote.

The FAA does not concur that the

proposed rule should be withdrawn.

The FAA has responded to the

commenter on this issue during

previous rulemaking concerning ‘‘blue

ice’’ on Boeing Model 727 series

airplanes. As stated in the preamble of

that final rule, the FAA pointed out that

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 aft lavatory drain systems

are detected and corrected in a timely

manner, ‘‘blue ice’’ incidents would go

untested and eventually someone would

be struck, perhaps fatally, by falling

‘‘blue ice.’’ To discount the unsafe

condition to persons on the ground

presented by falling ‘‘blue ice’’ would be

a gross breach of the FAA’s safety

obligations and commitment to the

public.

Request To Withdraw the Proposal:

Issue an Advisory Circular in Lieu of

an AD

This same commenter suggests that, if

some type of action must be taken, a

more manageable alternative to issuing

an AD should be considered. The

commenter suggests that such an

alternative could be the development of

an Advisory Circular (AC).

The FAA does not concur that

issuance of an AC would provide a

‘‘more manageable’’ method of

addressing the ‘‘blue ice’’ safety issue.

In certain cases, the issuance of an AC

is an appropriate first step to address a

concern at a more informal level than an

AD. In line with this approach,

Advisory Circular 120–39, ‘‘Hazards of

Waste Water Ice Accumulation

Separating from Aircraft in Flight,’’ was

issued on October 31, 1980. Paragraph

3. of that AC states, ‘‘Each operator

should initiate and accomplish

inspections and maintenance of waste

drain valves, caps, and heater systems to

the extent necessary to ensure that these

systems remain airworthy and function

as designed, to prevent ice build-up

from leaking waste water, and the

resultant separation from the aircraft.’’

The FAA concludes that the time

elapsed since the issuance of that AC

has given industry sufficient

opportunity to make this approach

work. The continuing problems with

‘‘blue ice,’’ however, demonstrate the

need for a more definitive solution; this

proposed rule is an appropriate

approach.

Request To Revise Rulemaking Criteria

To Ensure Level of Safety Is Cost

Beneficial

The ATA requests that the FAA

redefine the criteria used to determine

an ‘‘unsafe condition’’ so that the cost

of rulemaking (airworthiness directives)

is commensurate with the risks

associated with not correcting the

identified safety concern. Additionally,

the commenter states that in meetings

between the ATA and FAA

management, participants agreed to a

definition of ‘‘airworthiness.’’ The ATA

would like to see that definition

adopted for use in determining the need

for an airworthiness directive. ATA

states that without specific criteria and

definitions of these terms, the FAA’s

determination of an unsafe condition

and compliance period for adoption of

the proposed rule must be viewed as

subjective and, therefore, deficient as

rulemaking.

The FAA does not concur with the

commenter’s assertion that ‘‘without

further guidance, the FAA’s

determination of an unsafe condition

must be viewed as subjective and,

therefore, deficient as rulemaking.’’ The

legal question is whether the FAA has

identified an unsafe condition that may

exist or develop in other products of the

same type design. The FAA’s

determination on this issue is legally

appropriate (and the rulemaking is not

‘‘deficient’’) as long as the FAA has a

reasonable basis for that determination.

In this supplemental proposed rule, the

FAA finds that there is an unsafe

condition based on reports of damage to

engines, airframes, and property on the

ground that is associated with the

problems of ‘‘blue ice’’ that forms from

leaking lavatory drain systems on

transport category airplanes and

subsequently dislodges from the

airplane fuselage. Although these

reasons may be characterized as

‘‘subjective’’ because they are

qualitative rather than quantitative, the

FAA considers them to be appropriate

and sufficient to establish the

reasonableness of this proposed action.

Request To Consider the Cost Impact to

Airline Operators

One commenter states that in order to

standardize leak testing intervals at

1,000 and 4,500 flight hours, it will have

to install a part in the aft drain system

on its entire fleet, and in the forward

drain system on airplanes that do not

have Kaiser in-line ball valves installed

in the forward drain system. The

commenter requests that, since the

annual cost for this will be $8,064, the

FAA should reconsider that

requirement.

Another commenter asserts that

compliance with the proposed rule will

force airlines with good maintenance

programs and high levels of ‘‘blue ice’’

awareness to spend money

accomplishing repetitive leak tests that

will not add any additional levels of

safety to the aircraft or to people on the

ground. The commenter further states

that the additional ground time required

to perform these tests will also

complicate scheduling and hamper

efforts to increase aircraft utilization.

The FAA infers that the commenter is

requesting that the FAA reconsider the

cost impact of the proposed action.

The FAA acknowledges that the

obligation to maintain aircraft in an

airworthy condition is vital, but

sometimes expensive. ‘‘Blue ice’’
Federal Register / Vol. 62, No. 227 / Tuesday, November 25, 1997 / Proposed Rules 62711

frequently is not traceable to the

particular airplane, operator, and waste

system that produced it. Incidents of

leakage usually are not reported; only

the relatively serious leakage incidents

become known to the FAA. Previous

attempts to rely solely upon increased

maintenance while using lower

reliability hardware have not proven to

be successful. Therefore, a system to

prevent incidents of ‘‘blue ice’’ in the

fleet must be based upon reduction of

the number of incidents of leakage by

encouraging the use of more reliable

equipment, and requiring that, if an

incident of leakage does occur, it is

detected and corrected in a timely

manner.

In addition, 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 proposal is

unrealistic because, in the interest of

maintaining safe aircraft, prudent

operators would accomplish the

proposed actions even if they were not

required to do so.

Request To Distinguish Risks

Associated With Forward and Aft

Lavatories Drain Systems

Two commenters note that the

compliance times of the NPRM do not

reflect a difference between risks

associated with leakage from the

forward lavatory drain system and the

risks associated with leakage from the

aft drain. One of the commenters asserts

that operators who upgraded their

forward lavatory systems to address the

more significant safety concern over ice

ingestion in engines would still be

subject to the more stringent leak test

intervals of the aft lavatory drain

systems because of difficulties in

redesigning and implementing retrofit of

the aft lavatory drain systems. The

commenters assert that the differences

between the risks of leakage from the

forward lavatory should be reflected by

an adjustment to the proposed

compliance times.

The FAA does not concur that the

risks associated with either the forward

or aft lavatories should be distinguished

by an adjustment to the proposed

compliance times of the NPRM. As

discussed previously, ‘‘blue ice’’

detaching from the forward lavatory

could cause damage to the engine and

airframe, as well as present a hazard to

persons on the ground; ‘‘blue ice’’

detaching from the aft lavatory presents

a hazard to persons on the ground.

Regardless of whether the formation of

‘‘blue ice’’ occurs on the forward or aft

lavatory drain system, the resultant

unsafe condition would exist. Even if

the formation of ‘‘blue ice’’ on the aft

lavatory drain systems may appear to be

a less ‘‘significant’’ safety concern than

the forward systems, a safety concern

for those persons on the ground,

nevertheless, still exists.

Request To Involve Principal

Maintenance Inspectors (PMI)

This same commenter, in reference to

paragraph (b) of the previous NPRM,

contends that it is more appropriate for

the PMI, rather than the Seattle Aircraft

Certification Office (ACO) engineering

staff, to approve subsequent changes to

the maintenance program once the

program has been approved. The

commenter considers that the PMI is

more qualified than the ACO staff to

approve tasks on training, reporting, and

adjustment to the leak test intervals

based upon reliability program

recommendations. The commenter

points out that the subject matter of the

rule is clearly maintenance-related, and

the ACO staff is not equipped to

effectively respond to requests for

maintenance interval changes that may

occur. The commenter states that

paragraph (b) of the proposal should be

revised to include a statement that the

AD is no longer applicable once a

revision to the FAA-approved

maintenance program is implemented.

The FAA does not concur. Although

the FAA agrees that the PMI should

have oversight of most of the

requirements of the proposed alternative

maintenance program provision of the

rule, the FAA does not agree that the

PMI should be tasked with approving

certain adjustments of the program.

Failure threshold criteria and definitive

leak/failure rate data do not exist for the

majority of the subject valves; therefore,

a PMI would have no data on which to

base the approval of an extension of a

leak test interval for many valves with

the assurance that the valve would not

fail within the adjusted interval. In light

of this, it is essential that the FAA, at

the ACO level, have feedback as to the

leak and failure rates experienced in the

field. Although the PMI’s serve as the

FAA’s critical link with the operators

(and the PMI oversight responsibilities

will not be minimized by this AD

action), it is the staff of the ACO that

provides the engineering support

necessary to evaluate whether increases

in leak test intervals will maintain an

acceptable level of safety.

Further, the FAA considers it

essential that any adjustment of the

required leak test intervals, seal change

intervals, and data reporting procedures

should be approved in a uniform

manner to ensure that the program is

administered uniformly (and

appropriately) fleetwide. The staff of the

Seattle ACO is in the best position to

ensure that this is accomplished.

Additionally, given that possible new

relevant issues might be revealed during

the approval process, it is imperative

that the engineering staff at the ACO

have such feedback. In any case, the

ACO staff will work closely with the

cognizant PMI to ensure that any

approved revisions to this aspect of the

maintenance program are appropriate

and workable for the applicable airline.

Request To Increase Leak Test Intervals

for Pneudraulics Drain Valves

Several commenters request that the

leak test interval for Pneudraulics drain

valve having part number (P/N) 9527–1

be increased from the proposed 1,000

flight hours. Two of the commenters

requested the interval be increased to

2,000 flight hours; and one of the

commenters, the valve manufacturer,

requests that the interval be increased to

4,500 flight hours.

The FAA concurs partially. Since the

issuance of the NPRM, the FAA has

received new data regarding the inservice performance of the Pneudraulics

9527 series drain valve. The data was

obtained in accordance with procedures

similar to those of paragraphs (b) and (c)

of this supplemental NPRM. This data

revealed that, only two leak tests

failures were detected during a total

time of 847,927 hours on 412

Pneudraulics valves. In consideration of

this data, the FAA finds that, for those

operators who choose to comply with

the requirements of paragraph (a) of the

AD, this information justifies an

increase of the leak test interval of

Pneudraulics valves having P/N 9527

series from 1,000 hours to 2,000 hours.

Additionally, the FAA finds that, for

operators who choose to comply with

the maintenance option of paragraph (b)

of the AD, this information justifies an

increase of the leak test interval of the

Pneudraulics valves P/N 9527 series

from 1,000 hours to 4,000 hours.

Paragraphs (a) and (b) of this

supplemental NPRM have been revised

accordingly. However, if following the

requirements of paragraphs (b) and (c) of

this supplemental NPRM, similar data is

gathered by a number of operators and

are submitted to the FAA in support of

an extension of the leak check interval

for another type of valve, the FAA will

consider extension of the leak check

intervals for that valve for all operators

using the valve.
62712 Federal Register / Vol. 62, No. 227 / Tuesday, November 25, 1997 / Proposed Rules

Request To Increase Leak Test Intervals

of Certain Other Shaw Valves

One commenter states that its fleet

has a mixture of valves that have been

modified in accordance with Shaw

Service Bulletin SB 10101000B–38–1,

and valves that have not been modified

in accordance with that service bulletin.

The operator requests that the currently

proposed leak test interval of 600 flight

hours (for the valves that have not been

modified in accordance with the service

bulletin) be increased to equal the 1,000

flight hour leak test interval of the

valves modified in accordance with that

service bulletin. Because of the

operator’s high level of awareness, it

sees no safety compromise in requiring

the unmodified valves to be leak tested

at 1,000 flight hours.

The FAA does not concur. The

modifications described by the subject

service bulletin were designed to make

the valves less likely to leak. Therefore,

the leak test interval is permitted to be

increased only for those valves that have

been modified in accordance with Shaw

Service Bulletin SB 1010000B–38–1.

Request To Increase Leak Test Interval

for Other Shaw Valves

One commenter, a valve

manufacturer, requests that the leak test

interval for certain Shaw valves be

extended from 1,000 flight hours to

2,000 flight hours when the

maintenance procedures have been

revised and data have been submitted to

substantiate the increased interval.

The FAA concurs that when

maintenance procedures have been

revised and data have been submitted to

substantiate the increased interval,

approval may be granted to increase the

leak test intervals. Under the provisions

of this supplemental NPRM, an operator

has the option of proposing a change to

its maintenance program, gathering

data, and making a request for extension

of the leak test interval. Operators

interested in this option should contact

the Seattle Aircraft Certification Office

to discuss implementation of this option

before submitting the request to extend

the leak test intervals. If a number of

operators successfully follow this

procedure and provide data similar to

that provided for the Pneudraulics P/N

9527 series valve, the FAA will consider

an ‘‘across the board’’ increase for

extension of the leak check interval for

the valve that they are using. This

procedure is applicable to valve

manufacturers as well.

Request To Increase Interval of

Replacement of Pneudraulics Valve

Seals

One commenter, an operator, requests

that the replacements of the seals of the

Pneudraulics valves be extended from

the proposed ‘‘prior to 5,000 flight hours

after the effective date of the AD, and

thereafter at intervals not to exceed 18

months,’’ to replacement of the seal

‘‘every third leak test of the drain

system, or every 6,000 flight hours.’’

The commenter states that

implementation of the revised

compliance times would provide a

scheduling convenience, and would still

maintain an acceptable level of safety.

The FAA concurs that the intervals

for the repetitive replacements can be

extended somewhat. Since the

Pneudraulics valve seals are similar to

those used in the in-line drain valves

and replacement of those seals are

approved for longer replacement

intervals, the FAA has revised

paragraphs (a)(1)(ii) and (b)(1)(ii) of this

supplemental NPRM to require

accomplishment of repetitive seal

replacements at intervals not to exceed

18 months or 6,000 flight hours,

whichever occurs later.

Request To Revise Compliance Times

for Certain Seal Changes

One commenter, the airplane

manufacturer, requests that the

proposed rule be revised to provide for

an alternative repetitive interval for

accomplishment of the seal changes.

Specifically, the commenter requests

that, ‘‘or within 48 months after the last

documented seal change’’ be added after

the proposed repetitive interval of

‘‘5,000 flight hours’’ in paragraph

(b)(1)(i) of the proposed rule. The

commenter states that this alternative

repetitive interval would prevent

unnecessary seal changes for operators

that have recently performed the seal

change.

The FAA concurs that the requested

alternative repetitive interval would

prevent unnecessary seal changes for

operators that have recently performed

the seal change. The FAA considers that

those alternative repetitive intervals

provide an equivalent level of safety.

Therefore, the FAA has revised

paragraph (b)(3) of this supplemental

NPRM (which appeared as paragraph

(b)(1) of the previous proposal). The

FAA also has made a corresponding

change to paragraph (a)(8) of this

supplemental NPRM since it is similar

to the requirements of paragraph (b)(3)

of the supplemental NPRM.

Request To Delete Certain Seal Part

Numbers

One commenter, the airplane

manufacturer, requests that valve seal

part numbers 2651–329, 2651–334,

10101000C–G, 10101000C–M, and

1010000C–R be deleted from the

proposal. The commenter considers that

part numbers that have not been

installed, either in production or

retrofit, on Boeing Model 737 series

airplanes should not be cited in the

NPRM. The FAA concurs with the

commenter’s remarks, and has removed

all references to those parts numbers

from this supplemental NPRM.

Request To Mandate Leak Testing of All

Seals in the Lavatory System

One commenter notes that, while the

previous NPRM proposes leak testing of

the dump valve seal and the inner seal

of the drain valve of the service panel,

no testing of the outer cap/door seal is

required. The commenter states that

since the outer cap/door seal is the ‘‘last

resort’’ in preventing leakage of ‘‘blue

ice,’’ leak testing should be required of

the outer cap/door.

The FAA does not concur. Some valve

designs are such that the valve must be

partially disassembled (removing the

inner seal, interlocking inner plugs, etc.)

to allow the outer door to be tested,

which would invalidate the test of the

inner seal. Additionally, different valve

designs may require valve disassembly

and reassembly as part of the test

procedure with different test procedures

for different valve designs. These factors

complicate the specification of a usable

test of both inner and outer doors for all

existing valve designs. Therefore, the

FAA finds that the requirement to apply

3 PSID across the valve inner door and

to visually inspect the outer door seal

for damage that could cause leakage on

all service panel valves to be adequate

and appropriate. However, if an

operator prefers to test the outer door

and inspect the inner door, the FAA

will consider requests for an alternative

method of compliance as provided in

paragraph (f) of this proposed AD.

Request To Require a Lever Lock Cap

and a Vacuum Breaker Check Valve

One commenter states that, instead of

permitting a vacuum breaker check

valve to be used as an alternative to the

installation of a lever lock cap, the FAA

should require both of them. The

commenter states that a long history of

poor performance of check valves and

lever lock caps indicates that a

redundant system requiring both the

valve and cap would have greater

reliability.
Federal Register / Vol. 62, No. 227 / Tuesday, November 25, 1997 / Proposed Rules 62713

The FAA does not concur in this case.

The FAA acknowledges that redundant

systems generally provide a higher level

of safety; however, in this case,

redundancy to the check valve function

is provided by the vacuum breaker. In

the case of a check valve alone, the lever

lock cap provides redundancy to the

check valve. There are insufficient data

to show which combination is more

reliable.

However, service history information

indicates that vacuum breaker check

valves with poppet check valves (rather

than mushroom check valves) have a

greater reliability record. Therefore, the

FAA has removed reference to

Monogram Part Number 3765–175

(mushroom type) from paragraphs (a)

and (b) of this supplemental NPRM. By

requiring repair of leaking components

when ‘‘blue streaks’’ are observed, the

FAA intends that operators, through

their own experience, will determine

which combination of valves works the

best to avoid leakage. However, if the

FAA receives data indicating service

problems or unreliability with vacuum

breaker check valves using poppet

checks, the FAA may consider further

rulemaking action.

Request To Revise Approvals of Certain

Vacuum Breakers

Two commenters request that the

approval of vacuum breakers, as

referenced in the proposed rule, be

revised. One commenter requests that

reference to all Monogram part number

series 3765–175 or 3765–190 series be

deleted, and replaced with ‘‘* * * an

FAA-approved check valve with a

vacuum breaker * * *,’’ or replaced

with a specific reference to valves

having Shaw part number 301–0009–01.

This commenter states that the vacuum

breaker check valves leaked, and should

not be provided as an alternative to

installation of a lever lock cap on the

flush/fill line. The other commenter

requests that instead of specifying

particular part numbers, the approval

reference should be to ‘‘* * * an FAAapproved vacuum break in the * * *.’’

This commenter considers that this

would cover all vacuum breaker

manufacturers.

The FAA concurs partially. The FAA

has reviewed available service history

data and concluded that vacuum

breaker check valves of the poppet type

(such as Monogram part number series

3765–190) have fewer reports of leakage

than the vacuum breaker test valves of

the mushroom type (such as Monogram

part number 3765–175). Therefore, as

stated previously, the FAA has removed

reference to Monogram part number

3765–175 as an approved valve from

this supplemental NPRM.

The FAA also has reviewed the design

of Shaw part number 301–0009–01,

which is a vacuum breaker check valve

of the poppet type, and has added it as

an acceptable part number in

paragraphs (a)(8)(ii) and (b)(3)(ii) of this

supplemental NPRM.

Additionally, since the issuance of the

previous NPRM, another acceptable

valve for the flush/fill line has been

certified. The installation of Kaiser

Electroprecision flush/fill ball valve part

number series 0062–0009 has been

added to paragraphs (a)(8)(iii), (b)(3)(iii),

and (d)(3) of this supplemental NPRM

as an alternative method of preventing

leakage from the flush/fill line.

Request To Shorten Leak Test Intervals

of Flush/Fill Caps

The commenter states that there is no

discussion in the proposal of what

would prompt an airline to ensure

flush/fill caps are installed in all

positions prior to each flight. The

commenter contends that it is common

practice for caps to be removed from

airplanes due to their nuisance value.

The commenter also states that the

flush/fill caps, as well as the lever lock

caps, are difficult to operate and

commonly have the seals removed,

which render them inoperable on the

airplane. The commenter considers the

ease with which the seal is removed is

a design flaw of the valve itself.

Therefore, the commenter requests that

another device be considered instead of

the flush/fill caps that is not on the

exterior of the aircraft and cannot be

tampered with by ground maintenance

personnel. The commenter notes that a

device incorporated further upstream

with positive shut-off and anti-siphon

features would eliminate the ‘‘blue ice’’

that occurs at the flush/fill port.

Therefore, the commenter requests that,

until such a device can be developed

and FAA-approved, the leak tests and

inspections of this area should be

performed more frequently.

The FAA does not concur with the

commenter’s request. The FAA does not

consider it necessary to require an

additional inspection to ensure

installation of the flush/fill caps when

they are installed in accordance with an

AD. If, as the commenter asserts, cases

of uninstalled flush/fill caps commonly

occur, the FAA does not find that reason

to assume that operators would

continue that practice in the future if

operation without the flush/fill caps

would be a violation of an AD. Further,

lever lock caps are specified by this

supplemental NPRM precisely because

they must be in the closed position to

allow the service panel door to be

closed. In addition, this supplemental

NPRM specifies that if there is evidence

of leakage, the leaking device must be

corrected, or the lavatory drained and

placarded inoperative. Therefore, if

seals or caps are removed and result in

leakage, this provision will ensure that

the system is repaired before the

lavatory is returned to service.

Additionally, the FAA notes that the

vacuum break poppet type check valves

specified in the previous NPRM can be

used as an alternative to using lever lock

caps. The FAA is not aware of any data,

presently, that supports an increase or

decrease in the leak test intervals of the

devices on the flush/fill line.

Consequently, this supplemental NPRM

contains neither an increase nor a

decrease in the leak test intervals of

these devices. However, if such data

becomes available that supports a

decrease in the leak test intervals, the

FAA may consider additional

rulemaking.

Request To Revise the Leak Test of the

Inner Door of the Service Panel Drain

Valve

Several commenters request that the

leak test of the inner door of the service

panel drain be revised to require the test

to be run with the outer door open when

using a vacuum box so that the 3 PSID

differential is applied across the inner

door. One of these commenters, the

airplane manufacturer, points out that if

the outer door seal is good, the inner

door seal will not reflect a pressure

differential. For this reason, the FAA

concurs. The FAA has revised the

supplemental NPRM to specify that the

test be run with the outer door open

when using a vacuum box.

Request To Revise Testing of Drain

Panel Valves

One commenter requests that testing

of the drain valves cover both the inner

door of the valve and the outer door/cap

of the valve. The commenter also notes

that some valves have their primary

seals on the outer doors, not the inner

doors, so that omitting the test of the

outer door, as proposed in the NPRM,

results in the primary seal of the valve

being untested.

The FAA does not concur. As

discussed previously in the request to

mandate leak testing of all seals in the

lavatory system, the FAA has revised

the requirements of the leak testing of

the drain valves of service panels to

require applying 3 PSID across the valve

inner door and visually inspecting the

outer door seal for damage. This

approach should adequately test valves

with inner and outer doors. However, if
62714 Federal Register / Vol. 62, No. 227 / Tuesday, November 25, 1997 / Proposed Rules

an operator elects to test the outer door

and visually inspect the inner door, that

operator should apply for approval of an

alternative method of compliance under

the provisions of paragraph (f) of this

supplemental NPRM.

Request To Require Visual Inspection

of the Outer Cap/Door

Two commenters request that

paragraphs (a)(4) and (b)(2)(iii) of the

proposal be revised to delete the

requirement to perform a leak test of the

outer door of ‘‘donut’’ type valves, and

add a visual inspection of the outer

doors instead. The commenters state

that the ‘‘donut’’ valves are similar to

other valves in that they provide two

sealing surfaces. The commenters note

that for those other valves, the proposal

would require only a test of the inner

door or the sealing surface.

The FAA concurs and has revised

paragraphs (a)(4) and (b)(2)(iii) of this

supplemental NPRM accordingly. In

light of the fact that this supplemental

NPRM would require eventually

removing all ‘‘donut’’ valves and

replacing them with FAA-approved

valves, the FAA finds that, in the

interim, a visual inspection of the outer

doors, rather than a leak test, will

ensure an acceptable level of safety.

Request To Require a Leak Test of the

Outer Door of the Service Panel Drain

Another commenter states that since

the FAA required it to perform the leak

test of the outer door, the rules for

testing the service panel drain should

not be changed at this time. The

commenter states that by requiring leak

tests only of the inner door, the proposal

provides an unfair competitive

advantage in favor of its competitors

because some valves have their primary

seals on the outer doors instead of the

inner doors. In addition, by not

requiring a leak test of the outer door,

the actual primary seal of the valve

would not be tested.

The FAA does not concur with the

request to require leak tests of the outer

door seal. The FAA finds that

performing a leak test of the inner door

and visual inspections of the outer door

provide an acceptable level of safety.

However, if an operator chooses to test

the outer door and visually inspect the

inner door, under the provisions of

paragraph (f) of this supplemental

NPRM, that operator may request

approval of an adjustment of this

requirement if data are submitted to

substantiate that such an adjustment

would provide an acceptable level of

safety.

Request To Extend Leak Test Intervals

in Paragraph (b) of the Proposal

Several commenters state that the leak

test intervals specified in paragraph (b)

of the proposal should be relaxed so that

operators would be encouraged to select

it as an alternative to the

accomplishment of the requirements of

paragraph (a) of the proposal. One of the

commenters states that this same

request was made in response to the

proposed rule concerning ‘‘blue ice’’ for

Boeing Model 727 series airplanes, and

that the FAA did not respond to that

request. Several commenters assert that

paragraph (b) of the proposal should

additionally provide terminating action

once an operator’s FAA-approved

maintenance plan has been

incorporated.

The FAA does not concur with the

commenters’ request to increase the leak

test intervals specified in paragraph (b)

simply in order to encourage operators

to choose that option. For the reasons

specified previously under the ‘‘General

Changes to the Proposal: Revision of

Optional Maintenance Program’’ section

of this supplemental NPRM, the FAA

finds that the previously proposed

terminating action must be deleted.

Further, the expansion of leak test

intervals that are included in paragraph

(b) of this supplemental NPRM is

primarily related to the reliability of the

waste drain valves involved. The

additional requirements of paragraph (b)

provide assurance that expansion of the

intervals will not result in significant

leakage events in the time between the

leak tests. The FAA included paragraph

(b) of this supplemental NPRM not only

because it does contain certain

‘‘attractive’’ features, but also to provide

a format for verifiable empirical data to

serve as a reliability indicator for the

waste drain valves. To date, three

operators have opted to follow

requirements similar to those provided

in paragraph (b) of this supplemental

NPRM. The FAA concludes, therefore,

that compliance with the optional

provisions of paragraph (b) of this

supplemental NPRM is of value to some

operators.

Additionally, in reviewing the

preamble of AD 94–23–10 (applicable to

Boeing Model 727 series airplanes), the

FAA finds that the commenter’s request

regarding the leak test intervals of

paragraph (b) of that AD was

specifically addressed in the final rule.

The FAA’s response noted the revision

of several requirements of paragraph (b)

of that final rule to make it more

‘‘attractive’’ to operators; certain of

those revised requirements included

extended leak test intervals for some

valves.

Request To Revise Leak Test Intervals

for Service Panel Drain Valves

The airplane manufacturer requests

that paragraph (b)(2)(ii) of the proposal

be revised to increase the replacement

interval of the service panel drain valves

from 1,000 flight hours to 2,000 flight

hours. The commenter states that

increasing this interval would not

decrease the level of safety because of

other requirements of paragraph (b) of

the proposal. Further, the commenter

notes that two alternative methods of

compliance have been granted to

increase the interval to 2,000 flight

hours.

The FAA does not concur with the

commenter’s request to increase the leak

test interval ‘‘across the board’’ for

service panel drain valves at this time.

However, if data are submitted for

specific service panel drain valves in

accordance with the data gathering

requirements of paragraph (b) of this

supplemental NPRM, the FAA will

review the data and may consider

extending the leak test intervals

accordingly. If a number of operators

have successfully accomplished such

programs, the FAA will evaluate all the

data submitted for a particular valve and

consider an ‘‘across the board’’

extension of the leak test interval.

Request for Clarification of Compliance

Times

The airplane manufacturer requests

that compliance times in paragraph

(b)(4) of the proposal be revised. That

proposed compliance time is currently

specified as ‘‘* * * at intervals not to

exceed 4 calendar days or 45 flight

hours, whichever occurs later.’’ The

commenter requests that the phrase ‘‘not

to exceed’’ be deleted and replaced with

the word ‘‘of.’’ The manufacturer states

that the phrase ‘‘not to exceed’’ appears

to be in conflict with the phrase

‘‘* * * whichever occurs later.’’

Therefore, the manufacturer suggests

revising the compliance time to read ‘‘at

intervals of 4 calendar days or 45 flight

hours, whichever occurs later.’’

The FAA does not concur that the

phrases are in conflict with each other.

The phrases ‘‘at intervals not to exceed

4 calendar days or 45 flight hours,

whichever occurs later’’ are standard

phrasing the FAA uses routinely in

providing certain compliance times. The

phrase, ‘‘not to exceed,’’ allows

accomplishment of the required action

at frequencies less than the specified

intervals. The phrase, ‘‘whichever

occurs later,’’ allows an operator to

select the means of measuring the
Federal Register / Vol. 62, No. 227 / Tuesday, November 25, 1997 / Proposed Rules 62715

interval that results in less frequent

accomplishment of the required actions,

depending upon the operator’s

individual utilization rates. Therefore,

no change of compliance time is

required to paragraph (b)(4) of the

supplemental NPRM.

Request To Incorporate Paragraph (b)

Into Paragraph (f) of the Proposal

One commenter considers that the

provisions in paragraph (b) of the NPRM

are merely guidelines for submitting

alternative methods of compliance.

Therefore, the commenter requests that

paragraph (b) of the proposal be

incorporated into the paragraph that

specifically addresses alternative

methods of compliance [paragraph (f) of

the proposal].

The FAA does not concur. The

maintenance option provided by

paragraph (b) of this supplemental

NPRM provides for the acquisition of

data that are required to justify

extending leak test intervals.

Compliance with paragraph (b) of the

supplemental NPRM is an approved

method of establishing empirical data

on valve reliability. The FAA sees no

added value in changing the paragraph

numbering of the proposal. Moreover,

the FAA considers that a change in the

numbering of the paragraphs would

have the potential for added confusion

since an existing AD for the Boeing

Model 727 series airplanes concerning

‘‘blue ice’’ also has paragraph (b)

designated as the maintenance option.

Request To Revise Test Requirements

for Flush/Fill Line Anti-Siphon Valves

The airplane manufacturer requests

that paragraph (b)(3) of the proposal be

revised from ‘‘Thereafter, repeat the

requirements at intervals not to exceed

5,000 flight hours’’ to ‘‘Thereafter,

repeat the requirements at intervals not

to exceed 5,000 flight hours or 24

months.’’ The commenter notes that the

paragraph would then be consistent

with the test requirements of the in-line

drain valve in paragraph (b)(2)(i) of the

proposal.

The FAA does not concur. The

compliance times for testing the in-line

drain valves specified in paragraph

(b)(2)(i) of the supplemental NPRM were

based on supportive data to justify those

times. The FAA has not received data

justifying a similar compliance time for

the flush/fill line anti-siphon valve.

Request To Clarify Table 1 of the

Proposal

One commenter, a valve

manufacturer, requests that specific

Shaw Aero valves approved for a leak

test interval of 1,000 flight hours be

clarified. The FAA has revised Table 1

of this supplemental NPRM to clarify

specifically which Shaw valves have

been approved for use on Boeing Model

737 series airplanes.

Request To Base Leak Test Intervals for

Valves on Valve Quality

One commenter states that it is more

important to use a quality valve than a

‘‘maintenance program’’ to ensure

reliability. The commenter asserts that

maintenance programs should be

required of all airlines, so that leak test

intervals would be based on the quality

and performance of the hardware.

The FAA does not concur that claims

of valve quality should be the only basis

for determining leak test intervals, or

that all operators should be required to

follow the requirements of the optional

maintenance program [paragraph (b) of

the supplemental NPRM]. Extension of

the leak test interval is based primarily

upon hardware reliability, as stated

elsewhere in this supplemental NPRM.

However, verification of the actual

reliability of the hardware is difficult to

determine. Review of maintenance data

that is obtained through the

maintenance program and verified by

FAA Flight Standards plays a major role

in determining the extension of leak test

intervals. Although valve manufacturers

and some operators claim that the

hardware and systems currently in

service are providing adequate levels of

safety, incidents of ‘‘blue ice’’ continue

to occur.

Since leakage from the waste system

is not a reportable event according to

part 21 of the Federal Aviation

Regulations (14 CFR part 21), the FAA

included the provisions of paragraph (b)

of the proposal to make leakage from the

waste system a reportable event. Those

operators who choose to compile that

data will have documented information

to submit to the FAA as a basis for

increasing leak test intervals. As stated

earlier, the FAA has already used this

program to extend the leak test interval

for a certain valve.

With regard to the commenter’s

statement that all operators should be

required to follow a maintenance

program, the FAA has incorporated

requirements to periodically change

valve seals and correct any leakage

found in accordance with paragraph (a)

of this supplemental NPRM. The more

extensive requirements of the

maintenance program specified in

paragraph (b) of the supplemental

NPRM provide assurance that

significant leakage will not occur during

the expanded leak test intervals.

Request To Increase Certain Leak Test

Intervals

The ATA asserts that leak test

intervals of every 200 flight hours for

certain drain system valves cannot be

justified based on safety concerns with

‘‘blue ice.’’ The ATA requests that those

leak test intervals be extended.

The FAA does not concur. The

current leak test interval for certain

drain system valves is every 200 flight

hours, as required by AD 89–11–03.

Nevertheless, the FAA has continued to

receive reports of damage to airplanes.

The FAA intends to increase the leak

test interval only for those valves

documented to be reliable, in

accordance with the proposed

requirements of this supplemental

NPRM.

Request for Definition of ‘‘Vent Line’’

Another operator requests that the

term ‘‘vent line’’ be defined specifically.

The commenter questions if ‘‘vent line’’

as cited in the proposed AD refers only

to the portion of the line shown on the

Monogram check valve.

The FAA acknowledges that

clarification is necessary. The vent line

vacuum breaker is that portion of the

valve and vent line that functions as a

vacuum breaker, as opposed to the part

of the valve performing a ‘‘check valve’’

function. The intent of the previous

NPRM was to perform maintenance on

the vacuum breaker check valve and

ensure that the vacuum break feature

operates correctly. For clarification

purposes, reference to the term ‘‘vent

line’’ has been removed from this

supplemental NPRM, and the applicable

paragraphs have been revised to

reference a ‘‘vent line vacuum breaker.’’

Request To Revise Reference to Service

Information

The airplane manufacturer advised

that the correct service bulletins that

should be cited in paragraph (f)(2) of the

proposal are Boeing Service Bulletins

737–38–1026 (lavatory A), and 737–38–

1031 (lavatory F). Those service

bulletins describe alternative methods

of compliance with the requirements of

only paragraph (a)(2) of the

supplemental NPRM. The FAA

inadvertently cited an incorrect service

bulletin in the previous NPRM; the

supplemental NPRM has been revised to

cite the correct service bulletins.

Request To Change Reference to Certain

Drain System Valves

One commenter requests that the

description of the ‘‘donut’’ valves in

paragraphs (a)(4) and (b)(2)(iii) of the

NPRM be expanded to read, ‘‘For each

lavatory drain system that incorporates
62716 Federal Register / Vol. 62, No. 227 / Tuesday, November 25, 1997 / Proposed Rules

‘‘donut’’ plugs (Kaiser Electroprecision,

part number 4259–20 or 4259–31), or

FAA-approved equivalent, or

incorporates Kaiser Electroprecision

cap/flange, part numbers * * *.’’ The

FAA concurs, and has revised

paragraphs (a)(6) and (b)(2)(iv) of this

supplemental NPRM [which appeared

as paragraphs (a)(4) and (b)(2)(iii),

respectively, of the previous NPRM] to

provide clarification concerning the

specific ‘‘donut’’ valves, as suggested by

the commenter.

Request To Revise Notes 3 and 5 of the

Proposal

The airplane manufacturer requests

that Notes 3 and 5 of the NPRM be

corrected to reference Boeing

Maintenance Manual Section 38–32–00/

501 instead of the currently referenced

Boeing service letter.

The FAA acknowledges that Boeing

Maintenance Manual Section 38–32–00/

501 is the appropriate guidance for the

testing, and has revised Note 3 of this

supplemental NPRM accordingly.

However, since reference to guidance

for performing leak tests specifically

addressed in Note 5 of the previous

NPRM is no longer necessary or

applicable, it has been removed from

this supplemental NPRM. (Note 5 of this

supplemental NPRM now contains

information unrelated to NOTE 5 of the

previous NPRM.)

Request To Delete Reference to

Development of Future In-Line Drain

Valves

One commenter, a valve

manufacturer, requests that reference to

the development of future in-line drain

valves that would provide for possible

terminating action be deleted from the

proposal since that statement may

mislead airlines and other interested

parties to think that development and

approval of those valves is currently in

progress. The commenter states that the

NPRM is a place for facts, not

supposition of what might be. The

commenter further states that it believes

it has been ‘‘damaged’’ by mention of a

future valve, specifically when the FAA

has not considered existing in-service

data concerning the reliability of this

manufacturer’s valves.

The FAA acknowledges the

commenter’s request. The FAA has

removed reference to current in-line

drain valves, as well as possible future

development of those valves, from

consideration as terminating action for

certain requirements of this

supplemental NPRM. As discussed

previously in the preamble of this

supplemental NPRM, the FAA has

determined that terminating action for

the leak testing of the in-line valves

under an approved maintenance

program is no longer appropriate, based

on recent reports of leakage of drain

systems with in-line drain valves

installed.

In addition, it is common practice for

the FAA to provide information in

NPRM’s concerning possible

development and approval of various

corrective actions. For example, in

certain cases, compliance times for

corrective actions are based on a time

frame that is determined to be adequate

in order to develop, approve, and install

such corrective actions, e.g., repair,

parts, or modifications. Establishment of

a reasonable compliance time enables

the manufacturer to plan its schedules

and resources so that the corrective

action is made available to the airlines

well within the compliance time

established by an AD. For these reasons,

the FAA finds that the development and

approval of future parts, repair, or

modifications are not only relevant to

discussions in proposed rules, they are,

in certain cases, inherent to the

discussion itself.

Economic Impact

There are approximately 2,410 Model

737 series airplanes of the affected

design in the worldwide fleet. The FAA

estimates that 1,031 airplanes of U.S.

registry and 110 U.S. operators would

be affected by this proposed AD.

The proposed waste drain system leak

test and outer cap inspection would take

approximately 6 work hours per

airplane to accomplish, at an average

labor rate of $60 per work hour. Based

on these figures, the cost impact on U.S.

operators of these proposed

requirements of this AD is estimated to

be $371,160, or $360 per airplane, per

test/inspection.

Certain airplanes (i.e., those that have

‘‘donut’’ type drain valves installed)

may be required to be leak tested as

many as 15 times each year. Certain

other airplanes having other valve

configurations would be required to be

leak tested as few as 3 times each year.

Some airplanes that have various

combinations drain valves installed

would require approximately 2 leak

tests of one drain valve and 3 leak tests

of the other drain valve each year. Based

on these figures, the annual (recurring)

cost impact of the required repetitive

leak tests on U.S. operators is estimated

to be between $1,080 and $5,400 per

airplane per year.

With regard to replacement of

‘‘donut’’ type drain valves, the cost of a

new valve is approximately $1,200.

However, the number of leak tests for an

airplane that is flown an average of

3,000 flight hours a year is thereby

reduced from 15 tests to 3 tests. The cost

reduction because of the number of tests

required is approximately equal to the

cost of the replacement valve. Therefore,

no additional cost is incurred because of

this change.

The FAA estimates that it would take

approximately 1 work hour per airplane

lavatory drain to accomplish a visual

inspection of the service panel drain

valve cap/door seal and seal mating

surfaces, at an average labor cost of $60

per work hour. As with leak tests,

certain airplanes would be required to

be visually inspected as many as 15

times or as few as 3 times each year.

Based on these figures, the annual

(recurring) cost impact of the required

repetitive visual inspections on U.S.

operators is estimated to be between

$180 and $900 per airplane per year.

The proposed installation of the

flush/fill line cap would take

approximately 1 work hour per cap to

accomplish, at an average labor rate of

$60 per work hour. The cost of required

parts would be $275 per cap. There are

an average of 2.5 caps per airplane.

Based on these figures, the cost impact

on U.S. operators of these proposed

requirements of this AD is estimated to

be $863,463, or $838 per airplane.

The addition of the seal change

requirement to paragraph (a) will

require approximately 2 work hours to

accomplish, at an average labor cost of

$60 per hour. The cost of required parts

would be $200 per each seal change.

Based on these figures, the cost impact

on U.S. operators of these proposed

requirements of this AD is estimated to

be $329,920, or approximately $320 per

airplane per year.

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 proposed AD action, the FAA

estimates that it would take

approximately 40 work hours per

operator to incorporate the lavatory

drain system leak test procedures into

the maintenance programs, at an average
Federal Register / Vol. 62, No. 227 / Tuesday, November 25, 1997 / Proposed Rules 62717

labor cost of $60 per work hour. Based

on these figures, the cost impact of the

proposed maintenance revision

requirement of this AD action on the

110 U.S. operators is estimated to be

$264,000, or $2,400 per operator.

The cost impact figures discussed

above are based on assumptions that no

operator has yet accomplished any of

the current or 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 costbeneficial. When the FAA, as in this

proposed 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 proposed 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), 40113, 44701.

§ 39.13 [Amended]

2. Section 39.13 is amended by

removing amendment 39–6223 (54 FR

21933, May 22, 1989), and by adding a

new airworthiness directive (AD), to

read as follows:

Boeing: Docket 95–NM–111–AD. Supersedes

AD 89–11–03, Amendment 39–6223.

Applicability: All Boeing Model 737 series

100, 200, 300, 400 and 500 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

otherwise 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 request approval for an

alternative method of compliance in

accordance with paragraph (f) of this AD. The

request should include an assessment of the

effect of the modification, alteration, or repair

on the unsafe condition addressed by this

AD; and, if the unsafe condition has not been

eliminated, the request should include

specific proposed actions to address it.

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 or flush/fill systems and dislodged

from the airplane, accomplish the following:

(a) Except as provided by paragraph (b) of

this AD, accomplish the applicable

requirements of paragraphs (a)(1) through

(a)(9) of this AD at the time specified in each

paragraph. If the waste drain system

incorporates more than one type of valve,

only one of the waste drain system leak test

procedures (the one that applies to the

equipment with the longest leak test interval)

must be conducted at each service panel

location. The waste drain system valve leak

tests specified in this AD shall be performed

in accordance with the following

requirements: fluid shall completely cover

the upstream end of the valve being tested;

the direction of the 3 pounds per square inch

differential pressure (PSID) shall be applied

across the valve in the same direction as

occurs in flight; the other waste drain system

valves shall be open; and the minimum time

to maintain the differential pressure shall be

5 minutes. Any revision of the seal change

intervals or leak test intervals must be

approved by the Manager, Seattle Aircraft

Certification Office (SACO), FAA, Transport

Airplane Directorate.

(1) Replace the valve seals in accordance

with the applicable schedule specified in

paragraphs (a)(1)(i), (a)(1)(ii), and (a)(1)(iii) of

this AD.

(i) For each lavatory drain system that has

an in-line drain valve installed, Kaiser

Electroprecision part number series 2651–

278: Replace the seals within 5,000 flight

hours after the effective date of this AD, or

within 48 months after the last documented

seal change, whichever occurs later.

Thereafter, repeat the replacement of the

seals at intervals not to exceed 48 months.

(ii) For each lavatory drain system that has

a Pneudraulics part number series 9527

valve: Replace the seals within 5,000 flight

hours after the effective date of this AD, or

within 18 months of the last documented seal

change, whichever occurs later. Thereafter,

repeat the replacement of the seals at

intervals not to exceed 18 months or 6,000

flight hours, whichever occurs later.

(iii) For each lavatory drain system that has

any other type of drain valve: Replace the

seals within 5,000 flight hours after the

effective date of this AD, or within 18 months

after the last documented seal change,

whichever occurs later. Thereafter, repeat the

replacement of the seals at intervals not to

exceed 18 months.

(2) For each lavatory drain system that has

an in-line drain valve installed, Kaiser

Electroprecision part number series 2651–

278: Within 4,500 flight hours after the

effective date of this AD, and thereafter at

intervals not to exceed 4,500 flight hours,

accomplish the procedures specified in

paragraphs (a)(2)(i) and (a)(2)(ii) of this AD:

(i) Conduct a leak test of the toilet tank

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 toilet tank dump valve leak test must be

performed by filling the toilet tank with a

minimum of 10 gallons of water/rinsing fluid

and testing for leakage after a period of 5

minutes. Take precautions to avoid
62718 Federal Register / Vol. 62, No. 227 / Tuesday, November 25, 1997 / Proposed Rules

overfilling the tank and spilling fluid into the

airplane. The in-line drain valve leak test

must be performed with a minimum of 3

PSID applied across the valve.

(ii) If a service panel valve or cap is

installed, perform a visual inspection of the

service panel drain valve outer cap/door seal

and the inner seal (if the valve has an inner

door with a second positive seal), and the

seal mating surfaces for wear or damage that

may allow leakage.

(3) For each lavatory drain system that has

a service panel drain valve installed,

Pneudraulics part number series 9527:

Within 2,000 flight hours after the effective

date of this AD, accomplish the requirements

of paragraphs (a)(3)(i) and (a)(3)(ii) of this

AD. Thereafter, repeat the leak tests at

intervals not to exceed 2,000 flight hours.

(i) Conduct leak tests of the toilet tank

dump valve and service panel drain valve.

The toilet tank dump valve leak test must be

performed by filling the toilet tank with a

minimum of 10 gallons of water/rinsing fluid

and testing for leakage after a period of 5

minutes. Take precautions to avoid

overfilling the tank and spilling fluid into the

airplane. The leak test of the service panel

drain valve must be performed with a

minimum of 3 PSID applied across the valve

inner door/closure device.

(ii) Perform a visual inspection of the outer

cap/door and seal mating surface for wear or

damage that may cause leakage.

(4) For each lavatory drain system that has

a service panel drain valve installed, Kaiser

Electroprecision part number series 0218–

0032 or Shaw Aero part number/serial

number as listed in Table 1 of this AD:

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

requirements of paragraphs (a)(4)(i) and

(a)(4)(ii) of this AD:

TABLE 1.—SHAW AERO VALVES APPROVED FOR 1,000 FLIGHT HOUR LEAK TEST INTERVAL

Shaw waste drain valve part no. Serial Nos. of part number valve approved for 1,000-hour leak test interval

331 Series, 332 Series ............................................................................. All.

10101000B–A ........................................................................................... None.

10101000B–A–1 ....................................................................................... 0207–0212, 0219, 0226 and higher.

10101000BA2 ........................................................................................... 0130 and higher.

10101000C–A–1 ....................................................................................... 0277 and higher.

10101000C–J ............................................................................................ None.

10101000C–J–2 ........................................................................................ None.

10101000CN OR C–N .............................................................................. 3649 and higher.

Certain 10101000B valves ....................................................................... Any of these ‘‘B’’ series valves that incorporate the improvements of

Shaw Service Bulletin 10101000B–38–1, dated October 7, 1994, and

are marked ‘‘SBB38–1–58’’.

Certain 10101000C valves ....................................................................... Any of these ‘‘C’’ series valves that incorporate the improvements of

Shaw Service Bulletin 10101000C–38–2 dated October 7, 1994, and

are marked ‘‘SBC38–2–58’’.

Note 2: Table 1 is a comprehensive list of

all approved Shaw Valves, including those

valves approved by Parts Manufacturer

Approval (PMA) or Supplemental Type

Certificate (STC) for installation on Boeing

Model 737 series airplanes.

(i) Conduct a leak test of the toilet tank

dump valve and service panel drain valve.

The toilet tank dump valve leak test must be

performed by filling the toilet tank with a

minimum of 10 gallons of water/rinsing fluid

and testing for leakage after a period of 5

minutes. Take precautions to avoid

overfilling the tank and spilling fluid into the

airplane. The service panel drain valve leak

test must be performed with a minimum of

3 PSID applied across the valve inner door/

closure device.

(ii) Perform a visual inspection of the outer

cap/door and seal mating surface for wear or

damage that may cause leakage.

(5) 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 10101000B or 10101000C [except as

specified in paragraph (a)(4) 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

requirements of paragraphs (a)(5)(i) and

(a)(5)(ii) of this AD:

(i) Conduct a leak test of the dump valve

and the service panel drain valve. The leak

test of the dump valve must be performed by

filling the toilet tank with a minimum of 10

gallons of water/rinsing fluid and testing for

leakage after a period of 5 minutes.

Take precautions to avoid overfilling the

tank and spilling fluid on the airplane. The

service panel drain valve leak test must be

performed with a minimum 3 PSID applied

across the valve inner door/closure device.

(ii) Perform a visual inspection of the outer

cap/door and seal mating surface for wear or

damage that may cause leakage.

(6) For each lavatory drain system with a

lavatory drain system valve that incorporates

either ‘‘donut’’ plug, Kaiser Electroprecision

part number 4259–20 or 4259–31; Kaiser

Roylyn/Kaiser Electroprecision cap/flange

part numbers 2651–194C, 2651–197C, 2651–

216, 2651–219, 2651–235, 2651–256, 2651–

258, 2651–259, 2651–260, 2651–275, 2651–

282, 2651–286; or other FAA-approved

equivalent parts; accomplish the

requirements at the specified times of

paragraphs (a)(6)(i), (a)(6)(ii), and (a)(6)(iii) of

this AD. For the purposes of this paragraph

[(a)(6)], ‘‘equivalent part’’ means either a

‘‘donut’’ plug that mates with the cap/flange

having part numbers listed in this paragraph,

or a cap/flange that mates with the ‘‘donut’’

plug having part numbers listed in this

paragraph, such that the cap/flange and

‘‘donut’’ plug are used together as an

assembled valve.

(i) Within 200 flight hours after the

effective date of this AD, and thereafter at

intervals not to exceed 200 flight hours,

conduct leak tests of the toilet tank dump

valve and the service panel drain valve. The

leak test of the toilet tank dump valve must

be performed by filling the toilet tank with

a minimum of 10 gallons of water/rinsing

fluid and testing for leakage after a period of

5 minutes. Take precautions to avoid

overfilling the tank and spilling fluid on the

airplane. The service panel drain valve leak

test must be performed with a minimum 3

PSID applied across the valve.

(ii) Perform a visual inspection of the outer

door/cap and seal mating surface for wear or

damage that may cause leakage. This

inspection shall be accomplished in

conjunction with the leak tests of paragraph

(a)(6)(i).

(iii) Within 5,000 flight hours after the

effective date of this AD, replace the donut

valve (part numbers per paragraph (a)(6) of

this AD) with another type of FAA-approved

valve. Following installation of the

replacement valve, perform the appropriate

leak tests and seal replacements at the

intervals specified for that replacement valve,

as applicable.

(7) For each lavatory drain system not

addressed in paragraph (a)(2), (a)(3), (a)(4),

(a)(5), and (a)(6) 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 requirements of

paragraphs (a)(7)(i) and (a)(7)(ii) of this AD:

(i) Conduct a leak test of the toilet tank

dump valve and the service panel drain

valve. The toilet tank dump valve leak test

must be performed by filling the toilet tank

with a minimum of 10 gallons of water/

rinsing fluid and testing for leakage after a

period of 5 minutes. Take precautions to

avoid overfilling the tank and spilling fluid

on the airplane. The service panel drain

valve leak test must be performed with a

minimum 3 PSID applied across the valve

inner door/closure device.
Federal Register / Vol. 62, No. 227 / Tuesday, November 25, 1997 / Proposed Rules 62719

(ii) Perform a visual inspection of the outer

cap/door and seal mating surface for wear or

damage that may cause leakage.

(8) For flush/fill lines: Within 5,000 flight

hours after the effective date of this AD,

perform the requirements of paragraph

(a)(8)(i), (a)(8)(ii), or (a)(8)(iii) of this AD, as

applicable. Thereafter, repeat the

requirements at intervals not to exceed 5,000

flight hours, or 48 months after the last

documented seal change, whichever occurs

later.

(i) If a lever lock cap is installed on the

flush/fill line of the subject lavatory, replace

the seals on the toilet tank anti-siphon

(check) valve and the flush/fill line cap.

Perform a leak test of the toilet tank antisiphon (check) valve with a minimum of 3

PSID across the valve, in accordance with

paragraph (a)(8)(ii)(A) of this AD, as

applicable.

Note 3: The leak test procedure described

in Boeing Maintenance Manual, 38–32–00/

501, may be referred to as guidance for this

test if the toilet tank is filled to the level

specified in paragraph (a)(8)(ii)(A) of this AD.

(ii) If a vacuum breaker check valve,

Monogram part number series 3765–190, or

Shaw Aero Devises part number series 301–

0009–01 is installed on the subject lavatory,

replace the seals/o-rings in the valve. Perform

a leak test of the vacuum breaker check valve

and verify proper operation of the vent line

vacuum breaker in accordance with

paragraphs (a)(8)(ii)(A) and (a)(8)(ii)(B) of this

AD.

(A) Leak test the toilet tank anti-siphon

valve or the vacuum breaker check valve by

filling the toilet tank with water/rinsing fluid

to a level such that the bowl is approximately

half full (at least 2 inches above the flapper

in the bowl.) Apply 3 PSID across the valve

in the same direction as occurs in flight. The

vent line vacuum breaker on vacuum breaker

check valves must be pinched closed or

plugged for this leak test. If there is a cap/

valve at the flush/fill line port, the cap/valve

must be removed/open during the test. Check

for leakage at the flush/fill line port for a

period of 5 minutes.

(B) Verify proper operation of the vent line

vacuum breaker by filling the tank and

testing at the fill line port for back drainage

after disconnecting the fluid source from the

flush/fill line port. If back drainage does not

occur, replace the vent line vacuum breaker

or repair the vacuum breaker check valve in

accordance with the component maintenance

manual to obtain proper back drainage. As an

alternative to the above test technique, verify

proper operation of the vent line vacuum

breaker in accordance with the procedures of

the applicable component maintenance

manual.

(iii) If a flush/fill ball valve, Kaiser

Electroprecision part number series 0062–

0009 is installed on the flush/fill line of the

subject lavatory, replace the seals in the

flush/fill ball valve and the toilet tank antisiphon valve. Perform a leak test of the toilet

tank anti-siphon valve with a minimum of 3

PSID across the valve, in accordance with

paragraph (a)(8)(ii)(A) of this AD.

(9) As a result of the leak tests and

inspections required by paragraph (a) of this

AD, or if evidence of leakage is found at any

other time, accomplish the requirements of

paragraph (a)(9)(i), (a)(9)(ii), or (a)(9)(iii), as

applicable.

(i) If a leak is discovered, prior to further

flight, repair the leak. Prior to further flight

after repair, perform the appropriate leak test,

as applicable. 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 4: For purposes of this AD, ‘‘leakage’’

is defined as any visible leakage, if observed

during a leak test. At any other time (than

during a leak test), ‘‘leakage’’ is defined as

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 (a)(9)(i) or (a)(9)(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, operators may

revise the FAA-approved maintenance

program to include the requirements

specified in paragraphs (b)(1) through (b)(7)

of this AD. However, until the FAA-approved

maintenance program is so revised, operators

must accomplish the requirements of

paragraph (a) of this AD. The waste drain

system valve leak tests specified in this AD

shall be performed in accordance with the

following requirements: fluid shall

completely cover the upstream end of the

valve being tested; the direction of the 3

pounds per square inch differential pressure

(PSID) shall be applied across the valve in

the same direction as occurs in flight; the

other waste drain system valves shall be

open; and the minimum time to maintain the

differential pressure shall be 5 minutes. Any

revision of the seal change intervals or leak

test intervals must be approved by the

Manager, Seattle ACO.

(1) Replace the valve seals in accordance

with the applicable schedule specified in

paragraphs (b)(1)(i), (b)(1)(ii), or (b)(1)(iii) of

this AD.

(i) For each lavatory drain system that has

an in-line drain valve installed, Kaiser

Electroprecision part number series 2651–

278: Replace the seals within 5,000 flight

hours after the effective date of this AD, or

within 48 months of the last documented seal

change, whichever occurs later. Thereafter,

repeat the replacement of the seals at

intervals not to exceed 48 months.

(ii) For each lavatory drain system that has

a Pneudraulics part number series 9527

valve: Replace the seals within 5,000 flight

hours after the effective date of this AD, or

within 18 months of the last documented seal

change, whichever occurs later. Thereafter,

repeat the replacement of the seals at

intervals not to exceed 18 months or 6,000

flight hours, whichever occurs later.

(iii) For each lavatory drain system that has

any other type of drain valve: Replace the

seals within 5,000 flight hours after the

effective date of this AD, or within 18 months

of the last documented seal change,

whichever occurs later. Thereafter, repeat the

replacement of the seals at intervals not to

exceed 18 months.

(2) Conduct periodic leak tests of the

lavatory drain systems in accordance with

the applicable schedule specified in

paragraphs (b)(2)(i), (b)(2)(ii), (b)(2)(iii),

(b)(2)(iv), and (b)(2)(v) of this AD. Only one

of the waste drain system leak test

procedures (the one that applies to the

equipment with the longest leak test interval)

must be conducted at each service panel

location.

(i) For each lavatory drain system, that has

an in-line drain valve installed, Kaiser

Electroprecision part number series 2651–

278: Within 5,000 flight hours after the

effective date of this AD, or within 5,000

hours of the last documented leak test,

whichever occurs later, accomplish the

procedures specified in paragraphs

(b)(2)(i)(A) and (b)(2)(i)(B) of this AD.

Thereafter repeat the procedures at intervals

not to exceed 24 months or 5,000 flight

hours, whichever occurs later.

(A) Conduct a leak test 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 leak

test of the toilet tank dump valve must be

performed by filling the toilet tank with a

minimum of 10 gallons of water/rinsing fluid

and testing for leakage after a period of 5

minutes. Take precautions to avoid

overfilling the tank and spilling fluid on the

airplane. The in-line drain valve leak test

must be performed with a minimum of 3

PSID applied across the valve.

(B) If a service panel valve or cap is

installed, perform a visual inspection of the

service panel drain valve outer cap/door seal

and the inner seal (if the valve has an inner

door with a second positive seal), and the

seal mating surfaces, for wear or damage that

may allow leakage.

(ii) For each lavatory drain system that has

a service panel drain valve installed,

Pneudraulics part number series 9527:

Within 4,000 flight hours after the effective

date of this AD, or within 4,000 flight hours

of the last documented leak test, whichever

occurs later, accomplish the requirements of

paragraph (b)(2)(ii)(A) and (b)(2)(ii)(B) of this

AD. Thereafter, repeat the requirements at

intervals not to exceed 4,000 flight hours.

(A) Conduct leak tests of the toilet tank

dump valve and service panel drain valve.

The toilet tank dump valve leak test must be

performed by filling the toilet tank with a

minimum of 10 gallons of water/rinsing fluid

and testing for leakage after a period of 5

minutes. Take precautions to avoid

overfilling the tank and spilling fluid on the

airplane. The service panel drain valve leak

test must be performed with a minimum of

3 PSID applied across the valve inner door/

closure device.

(B) Perform a visual inspection of the outer

cap/door and seal mating surface for wear or

damage that may cause leakage.
62720 Federal Register / Vol. 62, No. 227 / Tuesday, November 25, 1997 / Proposed Rules

(iii) 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 10101000B, 10101000C, 331-

series, 332-series: Within 1,000 flight hours

after the effective date of this AD, or within

1,000 flight hours of the last documented

leak test, whichever occurs later, accomplish

the requirements of paragraphs (b)(2)(iii)(A)

and (b)(2)(iii)(B) of this AD. Thereafter,

repeat the requirements at intervals not to

exceed 1,000 flight hours.

(A) Conduct leak tests of the toilet tank

dump valve and service panel drain valve.

The toilet tank dump valve leak test must be

performed by filling the toilet tank with a

minimum of 10 gallons of water/rinsing fluid

and testing for leakage after a period of 5

minutes. Take precautions to avoid

overfilling the tank and spilling fluid on the

airplane. The service panel drain valve leak

test must be performed with a minimum of

3 PSID applied across the valve inner door/

closure device.

(B) Perform a visual inspection of the outer

cap/door and seal mating surface for wear or

damage that may cause leakage.

(iv) For each lavatory drain system with a

lavatory drain system valve that incorporates

either ‘‘donut’’ plugs Kaiser Electroprecision

part number 4259–20 or 4259–31; Kaiser

Roylyn/Kaiser Electroprecision cap/flange

part number 2651–194C, 2651–197C, 2651–

216, 2651–219, 2651–235, 2651–256, 2651–

258, 2651–259, 2651–260, 2651–275, 2651–

282, 2651–286; or other FAA-approved

equivalent part; accomplish the requirements

at the times specified in paragraphs

(b)(2)(iv)(A), (b)(2)(iv)(B), and (b)(2)(iv)(C) of

this AD. For the purposes of this paragraph

[(b)(2)(iv)], ‘‘FAA-approved equivalent part’’

means either a ‘‘donut’’ plug that mates with

the cap/flange having part numbers listed in

this paragraph, or a cap/flange that mates

with the ‘‘donut’’ plug having part numbers

listed in this paragraph, such that the cap/

flange and ‘‘donut’’ plug are used together as

an assembled valve.

(A) Within 200 flight hours after the

effective date of this AD, or within 200 flight

hours after the last documented leak test,

whichever occurs later, conduct leak tests of

the dump valve and the service panel drain

valve. Thereafter, repeat the tests at intervals

not to exceed 200 flight hours. The dump

valve leak test must be performed by filling

the toilet tank with a minimum of 10 gallons

of water/rinsing fluid and testing for leakage

after a period of 5 minutes. Take precautions

to avoid overfilling the tank and spilling

fluid on the airplane. The service panel drain

valve leak test must be performed with a

minimum 3 PSID applied across the valve.

(B) Perform a visual inspection of the outer

door/cap and seal mating surface for wear or

damage that may cause leakage. Perform this

inspection in conjunction with the leak tests

specified in paragraph (b)(2)(iv)(A).

(C) Within 5,000 flight hours after the

effective date of this AD, replace the donut

valve with another type of FAA-approved

valve. Following replacement of the valve,

perform the subsequent leak tests and seal

replacements at the intervals specified for the

new valve.

(v) For each lavatory drain system that

incorporates any other type of approved

valves: Within 400 flight hours after the

effective date of this AD, or within 400 flight

hours of the last documented leak test,

whichever occurs later, accomplish the

requirements of paragraph (b)(2)(v)(A) and

(b)(2)(v)(B) of this AD. Thereafter, repeat the

requirements at intervals not to exceed 400

flight hours.

(A) Conduct leak tests of the toilet tank

dump valve and the service panel drain

valve. The toilet tank dump valve leak test

must be performed by filling the toilet tank

with a minimum of 10 gallons of water/

rinsing fluid and testing for leakage after a

period of 5 minutes. Take precautions to

avoid overfilling the tank and spilling fluid

on the airplane. The service panel drain

valve leak test 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, only the

inner door must be tested.

(B) Perform a visual inspection of the outer

cap/door 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,

perform the requirements of paragraph

(b)(3)(i), (b)(3)(ii), or (b)(3)(iii), as applicable.

Thereafter, repeat the requirements at

intervals not to exceed 5,000 flight hours, or

48 months after the last documented seal

change, whichever occurs later.

(i) If a lever lock cap is installed on the

flush/fill line of the subject lavatory, replace

the seals on the toilet tank anti-siphon

(check) valve and the flush/fill line cap.

Perform a leak test of the toilet tank antisiphon (check) valve with a minimum of 3

PSID across the valve as specified in

paragraph (b)(3)(ii)(A) of this AD.

(ii) If a vacuum breaker check valve,

Monogram part number series 3765–190 or

Shaw Aero Devises part number series 301–

0009–01, is installed on the subject lavatory;

replace the seals/o-rings in the valve. Prior to

further flight, leak test the vacuum breaker

check valve, and test for proper operation of

the vent line vacuum breaker as specified in

paragraphs (b)(3)(ii)(A) and (b)(3)(ii)(B) of

this AD.

(A) Leak test the toilet tank anti-siphon

valve or the vacuum breaker check valve by

filling the toilet tank with water/rinsing fluid

to a level such that the bowl is approximately

half full (at least 2 inches above the flapper

in the bowl). Pressurize the airplane to 3

PSID. The vent line vacuum breaker on

vacuum breaker check valves must be

pinched closed or plugged for this leak test.

If there is a cap/valve at the flush/fill line

port, the cap/valve must be removed/opened

during the test. Test for leakage at the flush/

fill line port for a period of 5 minutes.

Note 5: The leak test procedure in the

appropriate section of Boeing Maintenance

Manual 38–32–00 may be used as guidance

for this test if the toilet tank is filled

approximately half full (at least 2 inches

above the flapper in the bowl).

(B) Verify proper operation of the vent line

vacuum breaker by filling the tank and

testing at the fill line port for back drainage

after disconnecting the fluid source from the

flush/fill line port. If back drainage does not

occur, replace the vent line vacuum breaker

or repair the vacuum breaker check valve in

accordance with the component maintenance

manual as required to obtain proper back

drainage.

(iii) If a flush/fill ball valve, Kaiser

Electroprecision part number series 0062–

009 installed on the flush/fill line of the

subject lavatory, replace the seals in the

flush/fill ball valve and the toilet tank antisiphon valve. Perform a leak test of the toilet

tank anti-siphon valve in accordance with

paragraph (b)(3)(ii))(A) of this AD.

(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 placard

inoperative.

(6) Provide training programs for

maintenance and servicing personnel that

include information on ‘‘Blue Ice

Awareness’’ and the hazards of ‘‘blue ice’’.

(7) If a leak is discovered during a leak test

required by paragraph (b) of this AD; or if

evidence of leakage is found at any other

time; or if repair/replacement of a valve (or

valve parts) is required as a result of a visual

inspection required in accordance with this

AD; prior to further flight, accomplish the

requirements of paragraph (b)(7)(i), (b)(7)(ii),

or (b)(7)(iii), as applicable.

Note 6: For purposes of this AD, ‘‘leakage’’

is defined as any visible leakage, if observed

during a leak test. At any other time (than

during a leak test), ‘‘leakage’’ is defined as

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.

(i) Repair the leak and, prior to further

flight after repair, perform a 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.

(ii) Repair or replace the valve or valve

parts.

(iii) In lieu of either paragraph (b)(7)(i) or

(b)(7)(ii), 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 test intervals required

by paragraph (b) of this AD must be approved

by the Manager, Seattle ACO, FAA, Transport

Airplane Directorate. Requests for such

revisions must be submitted to the Manager

of the Seattle ACO through the FAA

Principal Maintenance Inspector (PMI), and

must include the following information:

(1) The operator’s name;
Federal Register / Vol. 62, No. 227 / Tuesday, November 25, 1997 / Proposed Rules 62721

(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 test interval;

(6) Whether or not seals have been

replaced between the seal replacement

intervals required by this AD;

(7) Whether or not a service panel drain

valve is installed downstream of an in-line

drain valve, Kaiser Electroprecision part

number series 2651–278: Data on a service

panel valve installed downstream of an inline drain valve will not be considered as an

indicator of the reliability of the service

panel drain valve because the in-line valve

prevents potential leakage from reaching the

service panel drain valve.

(8) Whether or not leakage has been

detected between leak test intervals required

by this AD, and the reason for leakage (i.e.,

worn seals, foreign materials on sealing

surface, scratched or damaged sealing surface

on valve, etc.);

(9) Whether or not any cleaning, repairs, or

seal changes were performed on the valve

prior to conducting the leak test. [If such

activities have been accomplished prior to

conducting the periodic leak test, that leak

test 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 test will not cause that leak test to

be recorded as a failure. Debris removal of

major blockages done as part of normal

maintenance for previous flights is also

allowable and will not cause a leak test to be

recorded as a failure. Minor debris removal

that is not commonly removed during the

normal ground maintenance test should not

be removed prior to the leak test.]

Note 7: Requests for approval of revised

leak test intervals may be submitted in any

format, provided the data give the same level

of assurance specified in paragraph (c) above.

Results of an Environmental Quality Analysis

(EQA) examination and leak test on a

randomly selected high-flight-hour valve,

with seals that have not been replaced during

a period of use at least as long as the desired

interval, may be considered a valuable

supplement to the service history data,

reducing the amount of service data that

would otherwise be required.

Note 8: For the purposes of expediting

resolution of requests for revisions to the leak

test 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 test interval.

Note 9: In cases where changes are made

to a valve design approved for an extended

leak test interval such that a new valve dash

number or part number is established for the

valve, the FAA may not require extensive

service history data to approve the new valve

to the same leak test interval as the previous

valve design. Similarity of design, the nature

of the design changes, the nature and amount

of testing, and like factors will be considered

by the FAA to determine the appropriate data

requirements and leak test interval for a new

or revised valve based upon an existing

design.

(d) For all airplanes: Unless already

accomplished, within 5,000 flight hours after

the effective date of this AD, perform the

actions specified in paragraph (d)(1), (d)(2),

or (d)(3) of this AD:

(1) Install an FAA-approved lever/lock cap

on the flush/fill lines for all lavatories. Or

(2) Install a vacuum break, Monogram part

number series 3765–190, or Shaw Aero

Devises part number series 301–0009–01, in

the flush/fill lines for all lavatories. Or

(3) Install a flush/fill ball valve Kaiser

Electroprecision part number series 0062–

0009 on the flush/fill lines for all lavatories.

(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

tests 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 test has been performed once, each

subsequent leak test 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 test

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 test.

(2) For airplanes that have not been

previously maintained in accordance with

this AD, the first leak test 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) Alternative method(s) of compliance

with this AD:

(1) 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, Seattle

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,

Seattle ACO.

(2) Alternative methods of compliance

previously approved for AD 89–11–03, which

permit a 4,500-flight hour interval between

leak tests of the forward waste drain system

for those operators installing the

modifications specified in Boeing Service

Bulletin 737–38–1026, Revision 2, dated May

4, 1995, or Boeing Service Bulletin 737–38–

1031, Revision 1, dated April 20, 1995, and

later FAA-approved revisions, are considered

acceptable alternative methods of compliance

with the requirements of only paragraph

(a)(2) of this AD. For those operators, the

other requirements of this AD are still

required to be accomplished. All other

alternative methods of compliance approved

for AD 89–11–03 are terminated and are no

longer in effect.

Note 10: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Seattle ACO.

Note 11: For any valve that is not eligible

for the extended leak test intervals of this

AD: To be eligible for the extended leak test

intervals specified in paragraph (b) of this

AD, the service history data of the valve must

be submitted to the Manager, Seattle ACO,

FAA, Transport Airplane Directorate, with a

request for an alternative method of

compliance. 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, with 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 which include a winter season,

collected in accordance with the

requirements of paragraph (c) above, or a

similar program. One of the factors that the

FAA will consider in approving alternative

valve designs is whether the valve meets

Boeing Specification S417T105 or 10–62213.

However, meeting the Boeing specification is

not a prerequisite for approval of alternative

valve designs.

(g) Special flight permits may be issued in

accordance with §§ 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

November 18, 1997.

James V. Devany,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 97–30855 Filed 11–24–97; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97–NM–148–AD]

RIN 2120–AA64

Airworthiness Directives; Airbus Model

A320 and A321 Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes the

adoption of a new airworthiness

directive (AD) that is applicable to

certain Airbus Model A320 and A321

series airplanes. This proposal would

require replacement of the fuel pump

strainers with improved strainers. This