[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]
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