[Federal Register Volume 62, Number 26 (Friday, February 7, 1997)]
[Proposed Rules]
[Pages 5783-5785]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-3029]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-260-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 747-100, -
200, -300, and -400 series airplanes. This proposal would require a 
one-time visual inspection to determine the part number of the fuel 
shutoff valve installed in the outboard engines. The proposed AD also 
would require replacement of certain valves with new valves, or 
modification of the spar valve body assembly, and various follow-on 
actions. This proposal 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 
the proposed 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: Comments must be received by March 20, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-260-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; or ITT Aerospace Controls, 28150 Industry Drive, 
Valencia, California 91355. This information may be examined at the 
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Sulmo Mariano, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington; telephone (206) 227-
2686; fax (206) 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 96-NM-260-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules 
Docket No. 96-NM-260-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received several reports indicating that, due to high 
fuel pressure, the fuel system components of the outboard engines have 
failed on Boeing Model 747 series airplanes:
    1. Four incidents on airplanes powered by General Electric engines 
in which the fuel pump inlet of the engine was found to be cracked.
    2. Two incidents on airplanes powered by Rolls Royce engines, in 
which the low pressure fuel filter housing on the engine was found to 
be cracked.
    3. Two incidents on airplanes powered by Rolls Royce engines, in 
which the fuel cooled oil cooler on the engine was found to be 
ruptured.
    The existing design of the fuel shutoff spar valve installed on 
certain Model 747 series airplanes powered by General Electric and 
Rolls Royce engines can cause high pressure to occur in the fuel line. 
High fuel pressure can occur after the fuel shutoff spar valve and the 
engine fuel shutoff valve are closed during engine shutdown. This can 
result in heating of the trapped fuel and, because these valves are 
closed, the pressure created from the heating process is not released.
    High fuel pressure could result in failure of the fuel system 
components. If any of these components fails, the resultant fuel 
leakage could result in a possible engine fire.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-28A2199, dated August 1, 1996. The alert service bulletin describes 
procedures for performing a visual inspection to determine the part 
number of the fuel shutoff valve installed in the left and right-hand 
outboard engines; and replacement of certain valves with new valves and 
various follow-on actions, if necessary. [These follow-on actions 
include aligning valve(s), performing a check to detect leaks, and 
correcting any discrepancy.] The new fuel shutoff valve will ensure 
that the fuel pressure is released at 55-70 pounds per square inch 
gauge (p.s.i.g.).
    The FAA has also reviewed and approved ITT Service Bulletins 
SB125120-28-01, SB107970-28-01, and SB125334-28-01; all dated July 15, 
1996. These service bulletins describe procedures for modification of 
the spar valve body assembly. The modifications involve replacement of 
the thermal relief valves located in the valve disc with new thermal 
relief valves. Back pressure on the thermal relief valve can cause the 
valves to open at a higher pressure than desired. Accomplishment of 
these modifications will reduce the opening pressure of the thermal 
relief valves.

[[Page 5784]]

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require a one-time visual inspection to verify if the 
proper fuel shutoff valve is installed in the left and right-hand 
outboard engines. The proposed AD also would require replacement of any 
improper valve with a new valve or modification of the spar valve body 
assembly, and various follow-on actions. The actions would be required 
to be accomplished in accordance with the service bulletins described 
previously.
    The FAA also has determined that, following accomplishment of the 
proposed visual inspection and replacement or modifications, a one-time 
inspection to detect fuel leaks of the components between the fuel 
shutoff spar valve and the engine fuel shutoff valve to ascertain the 
integrity of these components is necessary. This proposed AD would 
require that this one-time inspection for leakage be accomplished and 
that any discrepant part be replaced with a serviceable part. These 
actions would be required to be accomplished 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).

Cost Impact

    There are approximately 418 Boeing Model 747-100, -200, -300, and -
400 series airplanes of the affected design in the worldwide fleet. The 
FAA estimates that 24 airplanes of U.S. registry would be affected by 
this proposed AD.
    It would take approximately 4 work hours per airplane to accomplish 
the proposed 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 the visual proposed by this AD on 
U.S. operators is estimated to be $5,760, or $240 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed requirements of 
this AD action, and that no operator would accomplish those actions in 
the future if this AD were not adopted.
    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.
    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 would 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.

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.


Sec. 39.13  [Amended]

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

Boeing: Docket 96-NM-260-AD.

    Applicability: Model 747-100, -200, -300, and -400 series 
airplanes, having line numbers 001 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 
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 (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 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 12 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 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) 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

[[Page 5785]]

any leak is detected, prior to further flight, replace the part with 
a serviceable part.
    (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, Seattle Aircraft Certification 
Office (ACO), FAA, Transport 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, 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.

    (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.

    Issued in Renton, Washington, on January 31, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-3029 Filed 2-6-97; 8:45 am]
BILLING CODE 4910-13-P