Federal Register / Vol. 65, No. 84 / Monday, May 1, 2000 / Rules and Regulations 25281

The cost impact figure discussed

above is based on assumptions that no

operator has yet accomplished any of

the requirements of this AD action, and

that no operator would accomplish

those actions in the future if this AD

were not adopted.

Regulatory Impact

The regulations adopted herein will

not have a substantial direct effect 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, it is

determined that this final rule does not

have federalism implications under

Executive Order 13132.

For the reasons discussed above, I

certify that this action (1) Is not a

‘‘significant regulatory action’’ under

Executive Order 12866; (2) is not a

‘‘significant rule’’ under DOT

Regulatory Policies and Procedures (44

FR 11034, February 26, 1979); and (3)

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 final evaluation has

been prepared for this action and it is

contained in the Rules Docket. A copy

of it may be obtained from the Rules

Docket at the location provided under

the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation

safety, Incorporation by reference,

Safety.

Adoption of the Amendment

Accordingly, pursuant to the

authority delegated to me by the

Administrator, the Federal Aviation

Administration amends 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

adding the following new airworthiness

directive:

2000–08–20 Lockheed: Amendment 39–

11706. Docket 99–NM–221–AD.

Applicability: Model L–1011–385–1, –1–

14, –1–15, and –3 series airplanes, equipped

with high pressure bleed valve controller

Hamilton Standard part number (P/N)

739084–2 or 739084–3 (Lockheed P/N

672286–103 or 672286–105); certificated in

any category.

Note 1: This AD applies to each airplane

identified in the preceding applicability

provision, regardless of whether it has been

modified, altered, or repaired in the area

subject to the requirements of this AD. For

airplanes that have been modified, altered, or

repaired so that the performance of the

requirements of this AD is affected, the

owner/operator must request approval for an

alternative method of compliance in

accordance with paragraph (c) 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 failures of the bleed air system

components, which could result in high

temperature air leaking into the cabin and/or

cargo areas and could possibly require an

emergency landing and evacuation,

accomplish the following:

(a) Within 14 months after the effective

date of this AD, modify the high pressure

bleed valve controller of each engine in

accordance with Lockheed Service Bulletin

093–36–065, dated February 9, 1999.

Note 2: Lockheed Service Bulletin 093–36–

065, dated February 9, 1999, references

Hamilton Standard Service Bulletin 36–1060,

Revision 1, dated March 1, 1977, as an

additional source of service information for

the modification of the high pressure bleed

valve controller of each engine.

(b) As of the effective date of this AD, no

person shall install on any airplane a high

pressure bleed valve controller having

Hamilton Standard part number (P/N)

739084–2 or 739084–3 (Lockheed P/N

672286–103 or 672286–105), unless it has

been modified in accordance with this AD.

Alternative Methods of Compliance

(c) 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, Atlanta

Aircraft Certification Office (ACO), FAA,

Small Airplane Directorate. Operators shall

submit their requests through an appropriate

FAA Principal Maintenance Inspector, who

may add comments and then send it to the

Manager, Atlanta ACO.

Note 3: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Atlanta ACO.

Special Flight Permits

(d) Special flight permits may be issued in

accordance with sections 21.197 and 21.199

of the Federal Aviation Regulations (14 CFR

21.197 and 21.199) to operate the airplane to

a location where the requirements of this AD

can be accomplished.

Incorporation by Reference

(e) The actions shall be done in accordance

with Lockheed Service Bulletin 093–36–065,

dated February 9, 1999. This incorporation

by reference was approved by the Director of

the Federal Register in accordance with 5

U.S.C. 552(a) and 1 CFR part 51. Copies may

be obtained from Lockheed Martin Aircraft &

Logistics Center, 120 Orion Street,

Greenville, South Carolina 29605. Copies

may be inspected at the FAA, Transport

Airplane Directorate, 1601 Lind Avenue,

SW., Renton, Washington; or at the FAA,

Small Airplane Directorate, Atlanta Aircraft

Certification Office, One Crown Center, 1895

Phoenix Boulevard, suite 450, Atlanta,

Georgia; or at the Office of the Federal

Register, 800 North Capitol Street, NW., suite

700, Washington, DC.

(f) This amendment becomes effective

on June 5, 2000.

Issued in Renton, Washington, on April 19,

2000.

Donald L. Riggin,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 00–10286 Filed 4–28–00; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99–NM–231–AD; Amendment

39–11707; AD 2000–08–21]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 747 Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment adopts a

new airworthiness directive (AD),

applicable to all Boeing Model 747

series airplanes, that requires repetitive

inspections to detect cracking of the

forward and aft inner chords and the

splice fitting of the forward inner chord

of the station 2598 bulkhead, and repair,

if necessary. This amendment is

prompted by reports of fatigue cracking

found in those areas. The actions

specified by this AD are intended to

detect and correct such cracking, which

could result in reduced structural

capability of the bulkhead and the

inability of the structure to carry

horizontal stabilizer flight loads.

DATES: Effective June 5, 2000.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of June 5,

2000.

ADDRESSES: The service information

referenced in this AD may be obtained

from Boeing Commercial Airplane

Group, P.O. Box 3707, Seattle,

Washington 98124–2207. This

information may be examined at the

25282 Federal Register / Vol. 65, No. 84 / Monday, May 1, 2000 / Rules and Regulations

Federal Aviation Administration (FAA),

Transport Airplane Directorate, Rules

Docket, 1601 Lind Avenue, SW.,

Renton, Washington; or at the Office of

the Federal Register, 800 North Capitol

Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Rick

Kawaguchi, Aerospace Engineer,

Airframe Branch, ANM–120S, FAA,

Transport Airplane Directorate, Seattle

Aircraft Certification Office, 1601 Lind

Avenue, SW., Renton, Washington

98055–4056; telephone (425) 227–1153;

fax (425) 227–1181.

SUPPLEMENTARY INFORMATION: A

proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39) to

include an airworthiness directive (AD)

that is applicable to all Boeing Model

747 series airplanes was published in

the Federal Register on November 5,

1999 (64 FR 60386). That action

proposed to require repetitive

inspections to detect cracking of the

forward and aft inner chords and the

splice fitting of the forward inner chord

of the station 2598 bulkhead, and repair,

if necessary.

Comments

Interested persons have been afforded

an opportunity to participate in the

making of this amendment. Due

consideration has been given to the

comments received.

Request to Reference New Service

Information

One commenter requests that the

proposed AD be revised to reference

Boeing Alert Service Bulletin 747–

53A2427, Revision 1, dated October 28,

1999. (The original issue of Boeing Alert

Service Bulletin 747–53A2427, dated

December 17, 1998, was referenced in

the proposal as the appropriate source

of service information for the proposed

actions.)

The FAA concurs with the

commenter’s request. Since the issuance

of the proposed rule, the FAA has

reviewed and approved Boeing Alert

Service Bulletin 747–53A2427, Revision

1. Revision 1 of the alert service bulletin

is substantially similar to the original

issue. However, Revision 1 includes

instructions for a one-time high

frequency eddy current (HFEC) and

repetitive detailed visual inspections to

detect cracking of the splice fitting of

the forward inner chord of the station

2598 bulkhead. Though not described in

the original issue of the alert service

bulletin, such inspections of the splice

fitting were described in the proposed

rule, so adding references to Revision 1

of the alert service bulletin to this final

rule would not add any additional

requirements beyond those that were

proposed. Thus, paragraphs (a), (b), and

(c) of this final rule have been revised

to reference both the original issue and

Revision 1 of the alert service bulletin

as appropriate sources of service

information for the requirements of this

AD.

In addition, the same commenter

requests that the FAA make several

specific changes to paragraphs (a) and

(b) of the proposed rule:

• Revise paragraph (a)(1) to refer to

Figure 2, Steps 1 and 2, of Boeing Alert

Service Bulletin 747–53A2427, Revision

1;

• Revise paragraph (a)(2) to refer to

Figure 2, View C and View A, of Boeing

Alert Service Bulletin 747–53A2427,

Revision 1;

• Revise paragraph (b)(1) to refer to

Figure 3, Steps 1 and 2, of Boeing Alert

Service Bulletin 747–53A2427, Revision

1; and

• Revise paragraph (b)(2) to refer to

Figure 2, View C and View A, of Boeing

Alert Service Bulletin 747–53A2427,

Revision 1.

The commenter states that these

changes will make inspection

instructions more explicit.

The FAA concurs with the

commenter’s request, and references to

specific figures and steps contained in

Revision 1 of the alert service bulletin

have been included in paragraphs (a)

and (b) of this final rule accordingly.

However, for consistency, where the

commenter recommends ‘‘View C and

View A’’ in its suggested revisions to

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

proposed AD, the FAA instead has

revised those paragraphs to refer to

‘‘Step 3’’ of the figures.

Request to Delete Notes

The same commenter that requests

that the FAA revise the proposed rule to

reference new service information also

requests that the FAA delete ‘‘NOTE 2’’

and ‘‘NOTE 4’’ of the proposed rule.

These notes explain that inspection

areas specified in paragraphs (a)(2) and

(b)(2) of the proposed rule are not

highlighted in certain figures in the

original issue of the alert service

bulletin. In Revision 1 of the alert

service bulletin, the figures to which

these notes refer have been updated to

show the subject inspection areas. The

commenter cites no justification for this

request, but the FAA infers that the

commenter considers ‘‘NOTE 2’’ and

‘‘NOTE 4’’ no longer necessary.

The FAA does not concur with the

commenter’s request. As stated

previously, this final rule has been

revised to reference both the original

issue and Revision 1 of the alert service

bulletin as appropriate sources of

service information. The information in

‘‘NOTE 2’’ and ‘‘NOTE 4’’ is still correct

for the original issue of the alert service

bulletin. No change to the final rule is

necessary in this regard.

Request to Clarify Repair Method

One commenter requests that the FAA

revise paragraph (d) of the proposed

rule to allow repairs of cracking of the

aft inner chord to be accomplished in

accordance with the applicable chapters

of the Boeing 747 Structural Repair

Manual (SRM) referenced in Boeing

Alert Service Bulletin 747–53A2427.

The commenter states that, without

clarification, paragraph (d) of the

proposal may be interpreted to require

approval by the Manager of the FAA’s

Seattle Aircraft Certification Office

(ACO) for repairs of cracking of the aft

inner chord because the alert service

bulletin provides the option to contact

Boeing for repair data instead of using

the SRM.

The FAA does not concur with the

commenter that any change is

necessary. Paragraph (c) of the proposed

rule (and this final rule) states that any

cracking detected during the inspections

required by paragraph (a)(1) or (b)(1) of

this AD must be repaired in accordance

with the alert service bulletin, except as

provided by paragraph (d) of this AD.

The FAA considers paragraph (d) of this

AD to apply to cracks on the aft inner

chord only if those cracks cannot be

repaired in accordance with the

chapters of the SRM listed in the alert

service bulletin. No change to the final

rule is necessary in this regard.

Conclusion

After careful review of the available

data, including the comments noted

above, the FAA has determined that air

safety and the public interest require the

adoption of the rule with the changes

previously described. The FAA has

determined that these changes will

neither increase the economic burden

on any operator nor increase the scope

of the AD.

Interim Action

This is considered to be interim

action. The manufacturer has advised

that it currently is developing a

modification that will positively address

the unsafe condition addressed by this

AD. Once this modification is

developed, approved, and available, the

FAA may consider additional

rulemaking.

Cost Impact

There are approximately 1,301 Model

747 series airplanes of the affected

Federal Register / Vol. 65, No. 84 / Monday, May 1, 2000 / Rules and Regulations 25283

design in the worldwide fleet. The FAA

estimates that 260 airplanes of U.S.

registry will be affected by this AD.

It will take approximately 2 work

hours per airplane to accomplish the

required HFEC inspection, at an average

labor rate of $60 per work hour. Based

on these figures, the cost impact of this

inspection on U.S. operators is

estimated to be $31,200, or $120 per

airplane.

It will take approximately 2 work

hours per airplane to accomplish the

required detailed visual inspections, at

an average labor rate of $60 per work

hour. Based on these figures, the cost

impact of this inspection on U.S.

operators is estimated to be $31,200, or

$120 per airplane, per inspection cycle.

The cost impact figures discussed

above are based on assumptions that no

operator has yet accomplished any of

the requirements of this AD action, and

that no operator would accomplish

those actions in the future if this AD

were not adopted.

Regulatory Impact

The regulations adopted herein will

not have a substantial direct effect 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, it is

determined that this final rule does not

have federalism implications under

Executive Order 13132.

For the reasons discussed above, I

certify that this action (1) Is not a

‘‘significant regulatory action’’ under

Executive Order 12866; (2) is not a

‘‘significant rule’’ under DOT

Regulatory Policies and Procedures (44

FR 11034, February 26, 1979); and (3)

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 final evaluation has

been prepared for this action and it is

contained in the Rules Docket. A copy

of it may be obtained from the Rules

Docket at the location provided under

the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation

safety, Incorporation by reference,

Safety.

Adoption of the Amendment

Accordingly, pursuant to the

authority delegated to me by the

Administrator, the Federal Aviation

Administration amends 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

adding the following new airworthiness

directive:

2000–08–21 Boeing: Amendment 39–11707.

Docket 99–NM–231–AD.

Applicability: All Model 747 series

airplanes, certificated in any category.

Note 1: This AD applies to each airplane

identified in the preceding applicability

provision, regardless of whether it has been

modified, altered, or repaired in the area

subject to the requirements of this AD. For

airplanes that have been modified, altered, or

repaired so that the performance of the

requirements of this AD is affected, the

owner/operator must request approval for an

alternative method of compliance in

accordance with paragraph (e) 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 detect and correct cracking of the

forward and aft inner chords and the splice

fitting of the forward inner chord of the

station 2598 bulkhead, which could result in

reduced structural capability of the bulkhead

and the inability of the structure to carry

horizontal stabilizer flight loads, accomplish

the following:

Initial Inspection

(a) Prior to the accumulation of 13,000 total

flight cycles, or within 1,000 flight cycles

after the effective date of this AD, whichever

occurs later: Accomplish the requirements

specified in paragraphs (a)(1) and (a)(2) of

this AD.

(1) Perform a high frequency eddy current

inspection (HFEC) to detect cracking of the

forward and aft inner chords of the station

2598 bulkhead, in accordance with Boeing

Alert Service Bulletin 747–53A2427, dated

December 17, 1998; or in accordance with

Figure 2, Steps 1 and 2, of Boeing Alert

Service Bulletin 747–53A2427, Revision 1,

dated October 28, 1999.

(2) Perform an HFEC inspection to detect

cracking of the splice fitting along the upper

and lower attachment to the forward inner

chord of the station 2598 bulkhead, as shown

in Figure 2, Detail A, of Boeing Alert Service

Bulletin 747–53A2427, dated December 17,

1998; or in accordance with Figure 2, Step 3,

of Boeing Alert Service Bulletin 747–

53A2427, Revision 1, dated October 28, 1999.

Note 2: Operators should note that

although the splice fitting is NOT highlighted

in Figure 2, Detail A, of Boeing Alert Service

Bulletin 747–53A2427, datedDecember 17,

1998, as it is in Figure 2 of Boeing Alert

Service Bulletin 747–53A2427, Revision 1,

dated October 28, 1999, the inspection

required by paragraph (a)(2) of this AD must

still be accomplished.

Repetitive Inspections

(b) Within 3,000 flight cycles after

accomplishment of the inspections required

by paragraph (a) of this AD: Accomplish the

inspections specified in paragraphs (b)(1) and

(b)(2) of this AD. Repeat the inspection

thereafter at intervals not to exceed 3,000

flight cycles.

(1) Perform a detailed visual inspection to

detect cracking of the forward and aft inner

chords of the station 2598 bulkhead, in

accordance with Boeing Alert Service

Bulletin 747–53A2427, dated December 17,

1998; or in accordance with Figure 3, Steps

1 and 2, of Boeing Alert Service Bulletin

747–53A2427, Revision 1, dated October 28,

1999.

Note 3: For the purposes of this AD, a

detailed visual inspection is defined as: ‘‘An

intensive visual examination of a specific

structural area, system, installation, or

assembly to detect damage, failure, or

irregularity. Available lighting is normally

supplemented with a direct source of good

lighting at intensity deemed appropriate by

the inspector. Inspection aids such as mirror,

magnifying lenses, etc., may be used. Surface

cleaning and elaborate access procedures

may be required.’’

(2) Perform a detailed visual inspection to

detect cracking of the splice fitting along the

upper and lower attachment to the forward

inner chord of the station 2598 bulkhead, as

shown in Figure 3, Detail A, of Boeing Alert

Service Bulletin 747–53A2427, dated

December 17, 1998; or in accordance with

Figure 3, Step 3, of Boeing Alert Service

Bulletin 747–53A2427, Revision 1, dated

October 28, 1999.

Note 4: Operators should note that

although the splice fitting is NOT highlighted

in Figure 3, Detail A, of Boeing Alert Service

Bulletin 747–53A2427, dated December 17,

1998, as it is in Figure 3 of Boeing Alert

Service Bulletin 747–53A2427, Revision 1,

dated October 28, 1999, the inspections

required by paragraph (b)(2) of this AD must

still be accomplished.

Repair

(c) If any cracking is detected during the

inspections required by paragraph (a)(1) or

(b)(1) of this AD, prior to further flight, repair

in accordance with Boeing Alert Service

Bulletin 747–53A2427, dated December 17,

1998, or

25284 Federal Register / Vol. 65, No. 84 / Monday, May 1, 2000 / Rules and Regulations

Revision 1, dated October 28, 1999; except as

provided by paragraph (d) of this AD.

(d) If any cracking is detected during the

inspections required by paragraph (a)(2) or

(b)(2) of this AD, or where the alert service

bulletin specifies that the manufacturer may

be contacted for disposition of certain repair

conditions, prior to further flight, repair in

accordance with a method approved by the

Manager, Seattle Aircraft Certification Office

(ACO), FAA, Transport Airplane Directorate;

or in accordance with data meeting the type

certification basis of the airplane approved

by a Boeing Company Designated

Engineering Representative (DER) who has

been authorized by the Manager, Seattle

ACO, to make such findings. For a repair

method to be approved by the Manager,

Seattle ACO, or a Boeing DER, as required by

this paragraph, the approval letter must

specifically reference this AD.

Alternative Methods of Compliance

(e) 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. Operators shall submit their requests

through an appropriate FAA Principal

Maintenance Inspector, who may add

comments and then send it to the Manager,

Seattle ACO.

Note 5: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Seattle ACO.

Special Flight Permits

(f) Special flight permits may be issued in

accordance with sections 21.197 and 21.199

of the Federal Aviation Regulations (14 CFR

21.197 and 21.199) to operate the airplane to

a location where the requirements of this AD

can be accomplished.

Incorporation by Reference

(g) Except as provided by paragraph (d) of

this AD, the actions shall be done in

accordance with Boeing Alert Service

Bulletin 747–53A2427, dated December 17,

1998, or Boeing Alert Service Bulletin 747–

53A2427, Revision 1, dated October 28, 1999.

This incorporation by reference was

approved by the Director of the Federal

Register in accordance with 5 U.S.C. 552(a)

and 1 CFR part 51. Copies may be obtained

from Boeing Commercial Airplane Group,

P.O. Box 3707, Seattle, Washington 98124–

2207. Copies may be inspected at the FAA,

Transport Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington; or at the

Office of the Federal Register, 800 North

Capitol Street, NW., suite 700, Washington,

DC.

Effective Date

(h) This amendment becomes effective on

June 5, 2000.

Issued in Renton, Washington, on April 19,

2000.

Donald L. Riggin,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 00–10285 Filed 4–28–00; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF THE INTERIOR

Minerals Management Service

30 CFR Part 250

Oil and Gas and Sulphur Operations in

the Outer Continental Shelf—Update of

Revised/Reaffirmed Documents

Incorporated by Reference

AGENCY: Minerals Management Service

(MMS), Interior.

ACTION: Technical amendment.

SUMMARY: This document makes

technical amendments to regulations

that were published in a final rule on

December 28, 1999 (64 FR 72756), and

which listed all documents incorporated

by reference in regulations governing oil

and gas and sulfur operations in the

Outer Continental Shelf (OCS). This

amendment incorporates Supplement 2

to the 21st Edition of American

Petroleum Institute (API) Specification

6D (SPEC 6D). The rulemaking of

December 28, 1999, incorporated API

SPEC 6D, 21st Edition, but not the

supplement.

EFFECTIVE DATE: May 31, 2000.

The incorporation by reference of

publications listed in the regulation is

approved by the Director of the Federal

Register as of May 31, 2000.

FOR FURTHER INFORMATION CONTACT: Carl

W. Anderson at (703) 787–1608.

SUPPLEMENTARY INFORMATION:

Background

Early in 1998, API requested that

MMS incorporate by reference

Supplements 1 and 2 (dated December

1996 and December 1997, respectively)

to API SPEC 6D. (Supplement 2 actually

fully incorporates and expands upon

Supplement 1.) For metal-to-metal

seated valves, the Supplements changed

from a ‘‘no visible leakage’’ standard to

‘‘allowable internal leakage rates’’

according to valve size. This raised two

concerns for MMS with regard to its

regulatory program. First, once an

attempt has been made to purge a

pipeline of all contents and close its

valves, how can an operator be sure that

the pipeline is properly isolated and

free of combustibles or pressure during

repairs? (Cutting into an existing

pipeline in preparation to repair it is

considered among the most hazardous

operations conducted offshore.) Second,

how can MMS be sure that out-ofservice pipelines isolated by block

valves are really shut down?

MMS issued Notice to Lessees and

Operators on the Outer Continental

Shelf (NTL) No. 98–16N in October

1998 rejecting Supplements 1 and 2 as

documents incorporated by reference.

MMS needed more time to discuss the

issues with API and to consider the

ramifications of the ‘‘allowable internal

leakage’’ standard for the OCS

regulatory program. MMS reasoned:

It may well be that the ‘‘no visible leakage’’

standard contained in the 21st and previous

editions of API SPEC 6D is an unreasonably

high standard for metal-to-metal seats. Metalto-metal seats are non-deforming compared

to non-metal-to-metal seats; therefore, it may

be reasonable to expect that some leakage

would occur between facing metal surfaces.

Nevertheless, there appears to be no data or

agreed-upon formula for predicting an

acceptable leakage rate.

The MMS made a concerted attempt

with API to collect data on this question

and held further discussions with

industry. In February 1999, MMS

proposed a research project on leakage

rates to API and asked them to survey

their members on their perceptions of

the ‘‘allowable leakage rates’’ and

willingness to participate in the

research project. Only 25 of 250

potential respondents replied. Their

answers indicated that few valve

suppliers believe that the ‘‘no visible

leakage’’ standard is realistic, other than

for special-purpose, non-off-the-shelf

(i.e., expensive) valves. Support for new

research was very limited.

Industry representatives maintained

that there is little formal data on leakage

rates. They explained, however, that

most correspondence on this subject

focuses on leakage rates contained in

International Standards Organization

Standard 5208, Rate D. These rates are

incorporated into Supplements 1 and 2.

The API SPEC 6D workgroup generally

agrees that these leakage rates are

reasonable and in line with their

experience.

Further discussions with the API

SPEC 6D workgroup revealed that

participants almost unanimously agree

that all pipeline valves leak after they

have been in service for a short time due

to operational residues and abrasion.