[Federal Register Volume 63, Number 200 (Friday, October 16, 1998)]
[Rules and Regulations]
[Pages 55517-55520]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-27459]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-260-AD; Amendment 39-10837; AD 98-21-29]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-100, -200, -300, -400, 
747SP, and 747SR Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 747-100, -200, -300, -400, 747SP, 
and 747SR series airplanes, that requires a one-time visual inspection 
to determine the part number of the fuel shutoff valve installed in the 
outboard engines. The AD also requires replacement of certain valves 
with new valves, or modification of the spar valve body assembly, and 
various follow-on actions. This amendment is prompted by reports 
indicating that, due to high fuel pressure, certain fuel system 
components of the outboard engines have failed on in-service airplanes. 
The actions specified by this AD are intended to prevent such high fuel 
pressure, which could result in failure of the fuel system components; 
this situation could result in fuel leakage and, consequently, lead to 
an engine fire.

DATES: Effective November 20, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 20, 1998.

ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207; or ITT Aerospace Controls, 28150 Industry Drive, 
Valencia, California 91355. This information may be examined at the 
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: Sulmo Mariano, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington; telephone (425) 227-
2686; 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 certain Boeing Model 747-100, -
200, -300, and -400 series airplanes was published in the Federal 
Register on February 7, 1997 (62 FR 5783). That action proposed to 
require a one-time visual inspection to determine the part number of 
the fuel shutoff valve installed in the outboard engines. That action 
also proposed to require replacement of certain valves with new valves, 
or modification of the spar valve body assembly, and various follow-on 
actions.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter supports the proposed rule.

Request To Revise Applicability of Proposed AD

    One commenter, the manufacturer, requests that the FAA limit the 
applicability of the proposed AD to airplanes having line numbers 629 
through 1006 inclusive. Another commenter requests that the proposed AD 
be limited to only Boeing Model 747-400 series airplanes.
    The manufacturer states that the subject fuel shutoff valve with 
the faulty thermal relief assembly was delivered to them no earlier 
than January 1986. Therefore, the manufacturer estimates that airplanes 
starting with line number 629--the first Boeing Model 747 series 
airplane delivered in January 1986--could be subject to the identified 
unsafe condition.
    The manufacturer also states that eight in-service events have 
occurred on Boeing Model 747-400 series airplanes powered by General 
Electric or Rolls Royce engines that were installed in the outboard 
positions only. There have been no confirmed events on General Electric 
or Rolls Royce engines installed in the inboard positions, or Boeing 
Model 747-400 series airplanes or Boeing 747-100, -200, and -300, 
747SP, and 747SR series airplanes (i.e., Classic airplanes) powered by 
Pratt & Whitney series engines. The manufacturer states that Boeing 
Alert Service Bulletin 747-28A2199, dated August 1, 1996 (referenced in 
the proposal as an appropriate source of service information), included 
line numbers 1 through 1006 inclusive because at the time the alert 
service bulletin was released, a comprehensive installation comparison 
had not been completed nor had the quantitative risk assessment been 
concluded.
    Since issuance of the alert service bulletin, the manufacturer has 
concluded that the close location of pneumatic ducts to the fuel lines 
for the outboard engine increases the possibility of higher pressures 
in the outboard engine fuel lines after the engines are shut down. The 
two Rolls Royce in-service events on the fuel cooled oil cooler (FCOC) 
can be attributed to the fact that the FCOC is a low pressure design.
    The second commenter believes that malfunctioning spar valve 
thermal relief assemblies are a secondary cause of the subject problem. 
The commenter states that the primary cause is the unique configuration 
of the outboard strut on Boeing Model 747-400 series airplanes that has 
an excessive heat source near the fuel line.
    The FAA concurs partially. The FAA does not agree with the 
commenter's request to limit the applicability of the final rule to 
only Boeing Model 747-400 series airplanes. The FAA points out that the 
incidents that prompted this AD occurred on certain Boeing Model 747 
series airplanes on which the spar valves had a modified thermal relief 
assembly. Because these spar valves may be installed on airplanes other 
than Model 747-400 series airplanes, the FAA has determined that these 
airplanes also are subject to the addressed unsafe condition. In 
addition, the heat from sources close to the fuel lines do not per se 
create the problem. However, the FAA does agree with the manufacturer's 
request to limit the applicability of the final rule to airplanes 
having line numbers 629

[[Page 55518]]

through 1006 inclusive since the Boeing Model 747 series airplane 
having line number 629 was the first airplane delivered on which the 
subject valve was installed. Therefore, the FAA has revised the 
applicability of the final rule accordingly.

Request To Extend Compliance Time of Visual Inspection

    Several commenters request that the compliance time for 
accomplishment of the visual inspection, as specified in paragraph (a) 
of the proposed AD, be extended from the proposed 12 months. One of 
these commenters states that a 24-month compliance time will allow the 
inspection to be accomplished during a regularly scheduled ``C'' check, 
and thereby eliminate any significant disruptions in flight schedules. 
Another commenter suggests a 15-month compliance time.
    The FAA concurs that the compliance time can be extended somewhat. 
The FAA's intent was that the inspection be conducted during a 
regularly scheduled maintenance visit for the majority of the affected 
fleet, when the airplanes would be located at a base where special 
equipment and trained personnel would be readily available, if 
necessary. Based on the information supplied by the commenters, the FAA 
now recognizes that 18 months corresponds more closely to the interval 
representative of most of the affected operators' normal maintenance 
schedules. Paragraph (a) of the final rule has been revised to reflect 
a compliance time of 18 months. The FAA does not consider that this 
extension of an additional 6 months for compliance will adversely 
affect safety.

Request To Revise Part Numbers

    One commenter requests that the FAA reference the suffix letter 
``A'' or ``M,'' as identified in Boeing Alert Service Bulletin 747-
28A2199, for part numbers specified in the proposed AD. The FAA does 
not concur. The commenter is incorrect that these suffixes appear in 
the subject Boeing alert service bulletin; they appear in ITT Service 
Bulletin SB125334-28-01. After reviewing the ITT service bulletin, the 
FAA finds that these suffixes are meant for the parts after they have 
been modified and are not used for the identification of the 
appropriate part numbers, as suggested by the commenter. Therefore, the 
FAA finds that no change to the final rule is necessary.

Request To Perform Inspection on One Valve at a Time

    Two commenters request that the FAA allow operators to inspect the 
fuel shutoff valves [required by paragraph (a) of the proposed AD] one 
at a time within the proposed 12-month compliance time. One commenter 
states that it will not be able to accomplish the proposed inspections 
and replacement (if required) without scheduling its airplanes out-of-
service for extended periods of time. The FAA concurs partially. If an 
operator elects to inspect the valves one at a time within the 
specified compliance time, it is the operator's prerogative to do so. 
The FAA finds no change to the final rule is necessary.

Request for Clarification of Requirements of Proposal

    Several commenters question whether the requirement to perform an 
inspection to detect fuel leaks on all four engines is correct in 
paragraph (b) of the proposed AD. Other commenters question why this 
inspection is necessary. Two other commenters believe that paragraph 
(b) of the proposed AD should address only ``the outboard engines'' or 
``engines number 1 and 4,'' rather than ``all four engines.'' These 
commenters question the reason for leak checking the inboard engines.
    The FAA finds that clarification is necessary. Although the FAA has 
only received reports of the high pressure occurring in the fuel line 
of the outboard engines, the FAA notes that an inboard engine could 
have been located previously in the outboard position. Therefore, as 
discussed previously in the notice of proposed rulemaking (NPRM), the 
FAA finds that it is necessary that the subject inspection be 
accomplished on all four engines. However, if an operator has 
documentation that demonstrates that the inboard engines have never 
been located in the outboard position, the FAA has determined that the 
operator does not have to conduct the inspection on those inboard 
engines. The FAA has revised the final rule to include a new paragraph 
(c) specifying this provision.

Request To Reference Another Source of Service Information

    One commenter requests that the FAA allow operators to accomplish 
the inspection required by paragraph (b) of the proposed AD in 
accordance with Section 28-22-07 of the 747 Airplane Maintenance 
Manual, rather than Chapter 71. If not, the commenter requests that the 
FAA reference a specific leak check in Chapter 71. The FAA does not 
concur. The FAA notes that the procedures for accomplishing the subject 
inspection are under the heading ``Fuel and Oil Leak Checks'' in 
Chapter 71. Therefore, no change to the final rule is necessary.

Request To Revise Proposed Actions Based on Future Service 
Information

    The manufacturer also states that it will revise Boeing Alert 
Service Bulletin 747-28A2199, dated August 1, 1996, to add a step to 
check the maintenance records for Model 747 series airplanes having 
line numbers 1 through 1006 inclusive, powered by General Electric and 
Roll Royce engines. If previous maintenance on the valves has been 
accomplished, the revised service bulletin would include procedures for 
inspection of the valve part number, and replacement, if necessary; if 
no maintenance on valves has been accomplished, the inspection would 
not be necessary.
    From this comment, the FAA infers that the commenter is requesting 
that the proposed AD be revised to include these procedures. The FAA 
does not concur. The manufacturer has not issued a revision to the 
referenced alert service bulletin. The FAA does not consider it 
appropriate to delay the issuance of this final rule. When the new 
service bulletin is issued, the FAA will review it and may consider 
future rulemaking action.

Request To Revise Cost Estimate

    One commenter requests that the FAA revise the cost estimate of the 
proposed AD to reflect the latest values cited in a Notice of Status 
Change for the alert service bulletin. The FAA does not concur. The FAA 
is unaware of a Notice of Status Change for Boeing Alert Service 
Bulletin 747-28A2199, dated August 1, 1996.

Explanation of Changes Made to Proposal

    The NPRM indicated that the airplanes affected by the proposed AD 
were Boeing Model 747-100, -200, -300, and -400 series airplanes. The 
proposed AD was intended to apply to all Boeing Model 747 series 
airplanes that have the faulty fuel shutoff spar valves installed, 
including Model 747SP and 747SR series airplanes. The estimate of the 
affected fleet size that was provided in the NPRM included those 
airplanes, which many, including the manufacturer, consider to be part 
of the Model 747-100 series. Those models are listed separately on the 
Model 747 Type Certificate Data Sheet. Therefore, in order to clarify 
that this AD does apply to those models, the FAA has revised the final 
rule to list the affected airplanes as Boeing Model 747-100, -200, -
300, -400, 747SP, and 747SR series airplanes.

[[Page 55519]]

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 described 
previously. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    There are approximately 418 Boeing Model 747-100, -200, -300, -400, 
747SP, and 747SR series airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 24 airplanes of U.S. registry 
will be affected by this AD.
    It will take approximately 4 work hours per airplane to accomplish 
the required one-time visual inspection to determine the part number of 
the valve, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact of this visual inspection required by 
this AD on U.S. operators is estimated to be $5,760, or $240 per 
airplane.
    Should an operator be required to accomplish the necessary one-time 
inspection to detect leaks and cracks (after replacement of the valve 
or modification of the assembly), it will take approximately 16 work 
hours per airplane, at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of this one-time inspection is 
estimated to be $960 per airplane.
    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.
    Should an operator elect to modify the valve body assembly of the 
fuel system rather than replace a discrepant valve, it would take 
approximately 20 work hours per airplane, at an average labor rate of 
$60 per work hour. Required parts would cost approximately $404 (2 
kits) per airplane. Based on these figures, the cost impact of any 
necessary modification action is estimated to be $1,604 per airplane.

Regulatory Impact

    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

98-21-29  Boeing: Amendment 39-10837. Docket 96-NM-260-AD.

    Applicability: Model 747-100, -200, -300, -400, 747SP, and 747SR 
series airplanes, having line numbers 629 through 1006 inclusive, 
and powered by General Electric or Rolls Royce engines; 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 (d) 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 high fuel pressure in components between the fuel 
shutoff spar valve and the engine fuel shutoff valve, which could 
result in failure of the fuel system components, lead to fuel 
leakage, and, consequently, lead to a possible engine fire, 
accomplish the following:
    (a) Within 18 months after the effective date of this AD, 
perform a one-time visual inspection to determine the part number of 
the fuel shutoff valve installed in the left- and right-hand 
outboard engines, in accordance with Boeing Alert Service Bulletin 
747-28A2199, dated August 1, 1996.
    (1) If a valve having part number (P/N) S343T003-40 (ITT P/N 
125334D-1) is installed, no further action is required by this AD.
    (2) If a valve having P/N S343T003-40 (ITT P/N 125334D-1) is not 
installed, prior to further flight, accomplish either paragraph 
(a)(2)(i) or (a)(2)(ii) of this AD.
    (i) Replace the valve with a new valve, in accordance with the 
alert service bulletin. Prior to further flight following 
accomplishment of the replacement, align the valve(s), perform a 
check to detect leaks, and correct any discrepancy, in accordance 
with the alert service bulletin. Or
    (ii) Modify the valve body assembly of the fuel system in 
accordance with ITT Service Bulletin SB125120-28-01, ITT Service 
Bulletin SB107970-28-01, and ITT Service Bulletin SB125334-28-01; 
all dated July 15, 1996.
    (b) Except as provided in paragraph (c) of this AD, prior to 
further flight following accomplishment of paragraph (a)(2) of this 
AD, perform a one-time inspection to detect fuel leaks of the 
components between the fuel shutoff spar valve and the engine fuel 
shutoff valve on all four engines, in accordance with the applicable 
section that pertains to Rolls Royce RB211 series engines or General 
Electric CF6-80C and CF6-45/50 series engines in Chapter 71 of the 
Boeing 747 Airplane Maintenance Manual (AMM). If any leak is 
detected, prior to further flight, replace the part with a 
serviceable part.
    (c) For airplanes having maintenance records that positively 
demonstrate that the inboard engines have never been located in the 
outboard position: Prior to further flight following accomplishment 
of paragraph (a)(2) of this AD, perform a one-time inspection to 
detect fuel leaks of the components between the fuel shutoff spar 
valve and the engine fuel shutoff valve on the outboard engines 
only, in accordance with the applicable section that pertains to 
Rolls Royce RB211 series engines or General Electric CF6-80C and 
CF6-45/50 series engines in Chapter 71 of the Boeing 747 AMM. If any 
leak is detected, prior to further flight, replace the part with a 
serviceable part.
    (d) 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 Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate. Operators shall 
submit their requests through an

[[Page 55520]]

appropriate FAA Principal Maintenance Inspector, who may add 
comments and then send it to the Manager, Seattle ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (e) 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.
    (f) Except as provided by paragraphs (b) and (c) of this AD, the 
actions shall be done in accordance with Boeing Alert Service 
Bulletin 747-28A2199, dated August 1, 1996; or ITT Service Bulletin 
SB125120-28-01, ITT Service Bulletin SB107970-28-01, and ITT Service 
Bulletin SB125334-28-01; all dated July 15, 1996. 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; or ITT Aerospace Controls, 28150 
Industry Drive, Valencia, California 91355. 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.
    (g) This amendment becomes effective on November 20, 1998.

    Issued in Renton, Washington, on October 6, 1998.
Darrell M. Pederson,
 Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-27459 Filed 10-15-98; 8:45 am]
BILLING CODE 4910-13-P