[Federal Register Volume 63, Number 152 (Friday, August 7, 1998)]
[Rules and Regulations]
[Pages 42210-42213]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-20969]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-180-AD; Amendment 39-10695; AD 98-16-19]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to all Boeing Model 747 series airplanes. This action 
requires, for certain airplanes, revising the Airplane Flight Manual 
(AFM) to advise the flightcrew of limitations on dry (no fuel) 
operation of the override/jettison pumps of the center wing fuel tank. 
This action also requires repetitive inspections for wear or damage of 
the inlet check valves and inlet adapters of the override/jettison 
pumps, and replacement of the check valves and pumps with new or 
serviceable parts, if necessary. Such replacement terminates the AFM 
revision. This amendment is prompted by a report that inlet adapters of 
override/jettison pumps were found to be worn excessively, which 
allowed contact to occur between the inlet check valve and the inducer. 
The actions specified in this AD are intended to ensure that the 
flightcrew is advised of the hazards of dry operation of the override/
jettison pumps of the center wing fuel tank, and to detect and correct 
wear or damage to the inlet check valves and inlet adapters of the 
override/jettison pumps; such conditions, if not corrected, could 
result in a fire or explosion in the fuel tank during dry operation.

DATES: Effective August 24, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of August 24, 1998.
    Comments for inclusion in the Rules Docket must be received on or 
before October 6, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-180-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    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 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.

FOR FURTHER INFORMATION CONTACT: Sulmo Mariano, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2686; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: The FAA has received a report indicating 
that, during an inspection of the fuel system on a Boeing Model 747-400 
series airplane, inlet adapters of the override/jettison pumps of the 
center wing fuel tank were found to be worn. Two of the inlet adapters 
had worn down enough to cause damage to the rotating blades of the 
inducer. The inlet check valves also had significant damage. Another 
operator reported damage to the inlet adapter that was so severe that 
contact had occurred between the steel disk of the inlet check valve 
and the steel screw that holds the inducer in place. (Such wear 
conditions were not found on the override/jettison pumps of the center 
wing fuel tank that were recovered from a Model 747-400 series airplane 
involved in an accident, in which the airplane broke up shortly after 
takeoff from John F. Kennedy International Airport in Jamaica, New 
York, on July 17, 1996. In addition, those pumps are not believed to 
have been operating on the accident airplane during that flight because 
mission fuel had not been loaded into the center tank.)
    Wear to the inlet adapters has been attributed to contact between 
the inlet check valve and the adapter. Vibration, possibly due to 
oscillations of the fuel flow, causes wear to both the stainless steel 
disk of the inlet check valve and the inlet adapter. The wear to the 
inlet adapter is accelerated by the steel disk of the check valve 
chafing against the edge of the adapter. Such excessive wear of the 
inlet adapter can lead to contact between the inlet check valve and 
inducer, which could result in pieces of the check valve being ingested

[[Page 42211]]

into the inducer and damaging the inducer and impellers. Contact 
between the steel disk of the inlet check valve and the steel rotating 
inducer screw can cause sparks. Also, during dry (no fuel) operation of 
the fuel pump, excessive temperatures at the contact point between the 
inlet check valve and the inducer could create an ignition source for 
fuel vapors. Wear and damage to the inlet check valves and inlet 
adapters of the override/jettison pumps of the center wing fuel tank, 
if not corrected, could result in a fire or explosion in the fuel tank 
during dry operation of the pumps.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-28A2212, Revision 2, dated May 14, 1998. This alert service 
bulletin describes procedures for repetitive detailed visual 
inspections for wear or damage of the inlet check valves and inlet 
adapters of the override/jettison pumps of the center wing fuel tank; 
and replacement of the check valves and override/jettison pumps with 
new or serviceable parts, if necessary. The inspections involve 
defueling the center wing tank; removing the override/jettison pumps; 
examining the seals, hinge pins, and springs of the inlet check valves 
for wear or damage; and measuring the amount of wear to the stainless 
steel disks of the inlet check valves and to the inlet adapters.

Explanation of the Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design, this AD is 
being issued to ensure that the flightcrew is advised of the hazards of 
dry operation of the override/jettison pumps of the center wing fuel 
tank; and to detect and correct wear or damage to the inlet check 
valves and inlet adapters of the override/jettison pumps, which could 
result in a fire or explosion in the fuel tank during dry operation. 
This AD requires, for certain airplanes, a revision to the Limitations 
Section of the FAA-approved Airplane Flight Manual (AFM) to provide the 
flightcrew with restrictions on operating the override/jettison pumps 
with less than a certain amount of fuel in the center wing fuel tank. 
This AD also requires, for all airplanes, repetitive detailed visual 
inspections for wear or damage of the inlet check valves and inlet 
adapters of the override/jettison pumps of the center wing fuel tank, 
and replacement of the check valves and override/jettison pumps with 
new or serviceable parts, if necessary. Accomplishment of the 
inspections terminates the AFM revision.

Determination of Threshold for AFM Revision

    This AD requires that the AFM be revised for airplanes that have 
accumulated 20,000 total hours time-in-service. The 20,000-hour 
threshold was established based on reports from the manufacturer that 
all of the airplanes on which wear or damage to the inlet check valves 
and inlet adapters of the override/jettison pumps was detected had 
accumulated more than 40,000 total hours time-in-service. The FAA finds 
that a threshold of 20,000 total hours time-in-service for requiring 
the accomplishment of the AFM revision is warranted.

Differences Between Rule and Alert Service Bulletin

    Operators should note that Boeing Alert Service Bulletin 747-
28A2212, Revision 2, dated May 14, 1998, recommends that the 
accomplishment of the initial inspections be completed within 120 days 
(from the date of receipt of the service bulletin). While the FAA 
agrees that 120 days is an appropriate time interval in which the 
initial inspections can be accomplished and an adequate level of safety 
maintained, this AD specifies a compliance time of 90 days for the 
accomplishment of the initial inspections. This 90-day compliance time 
was developed by taking into account the manufacturer's recommended 
120-day compliance time from May 14, 1998 (the service bulletin issue 
date), as well as the number of work hours required to accomplish the 
specified actions and the size of the affected U.S.-registered fleet. 
In consideration of these factors, the FAA finds that a compliance time 
of 90 days is appropriate in order to address the identified unsafe 
condition in a timely manner without compromising safety.

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.

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 98-NM-180-AD.'' The postcard will be date stamped and 
returned to the commenter.

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.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft,

[[Page 42212]]

and that it is not a ``significant regulatory action'' under Executive 
Order 12866. It has been determined further that this action involves 
an emergency regulation under DOT Regulatory Policies and Procedures 
(44 FR 11034, February 26, 1979). If it is determined that this 
emergency regulation otherwise would be significant under DOT 
Regulatory Policies and Procedures, a final regulatory evaluation will 
be prepared and placed in the Rules Docket. A copy of it, if filed, 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:

98-16-19  Boeing: Amendment 39-10695. Docket 98-NM-180-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 (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 ensure that the flightcrew is advised of the hazards of dry 
(no fuel) operation of the override/jettison pumps of the center 
wing fuel tank, and to detect and correct wear or damage to the 
inlet check valves and inlet adapters of the override/jettison 
pumps, which, if not corrected, could result in a fire or explosion 
in the fuel tank during dry operation; accomplish the following:
    (a) For airplanes that have accumulated 20,000 total hours time-
in-service or more as of the effective date of this AD: Within 14 
days after the effective date of this AD, revise the Limitations 
section of the FAA-approved Airplane Flight Manual (AFM) to include 
the following procedures. This may be accomplished by inserting a 
copy of this AD into the AFM.
    ``If the center tank override/jettison fuel pumps are to be 
used, there must be at least 17,000 pounds (7,720 kilograms) of fuel 
in the center tank prior to engine start.
    Do not operate the center tank override/jettison fuel pumps with 
less than 7,000 pounds (3,200 kilograms) of fuel in the center tank. 
For airplanes with an inoperative center tank scavenge system, this 
7,000 pounds of center tank fuel must be considered unusable.
    If the center tank override/jettison fuel pumps circuit breakers 
are tripped, do not reset.''
    (b) Prior to the accumulation of 10,000 total hours time-in-
service, or within 90 days after the effective date of this AD, 
whichever occurs later, accomplish the requirements of paragraphs 
(b)(1) and (b)(2) of this AD, in accordance with the Accomplishment 
Instructions specified in Boeing Alert Service Bulletin 747-28A2212, 
Revision 2, dated May 14, 1998.
    (1) Perform a detailed visual inspection for wear or damage of 
the inlet check valve of the left and right override/jettison pumps 
of the center wing fuel tank.
    (i) If the inlet check valve passes all wear and damage 
criteria, as specified in Figure 3 of the alert service bulletin, 
accomplish the actions specified in paragraph (b)(1)(i)(A), 
(b)(1)(i)(B), or (b)(1)(i)(C) of this AD, as applicable.
    (A) If the wear to the stainless steel disk is less than or 
equal to 0.70 inch, and does not penetrate the disk, repeat the 
inspection thereafter at intervals not to exceed 10,000 hours time-
in-service after the last inspection.
    (B) If the wear to the stainless steel disk is greater than 0.70 
inch, and does not penetrate the disk, repeat the inspection 
thereafter at intervals not to exceed 1,000 hours time-in-service 
after the last inspection.
    (C) If the wear penetrates the stainless steel disk of the inlet 
check valve, prior to further flight, accomplish the actions 
specified in paragraph (b)(1)(ii) of this AD.
    (ii) If the inlet check valve fails any wear or damage criteria, 
as specified in Figure 3 of the alert service bulletin, prior to 
further flight, replace the existing check valve with a new or 
serviceable check valve, in accordance with the alert service 
bulletin. Repeat the inspection thereafter at intervals not to 
exceed 10,000 hours time-in-service after the last inspection.
    (2) Perform a detailed visual inspection for wear or damage of 
the inlet adapter of the left and right override/jettison pumps of 
the center wing fuel tank.
    (i) If the wear to the inlet adapter is less than or equal to 
0.50 inch, prior to further flight, reinstall the existing override/
jettison pump, in accordance with the alert service bulletin. Repeat 
the inspection thereafter at intervals not to exceed 10,000 hours 
time-in-service after the last inspection.
    (ii) If the wear to the inlet adapter is greater than 0.50 inch, 
but less than 0.60 inch, prior to further flight, accomplish the 
actions required by either paragraph (b)(2)(ii)(A) or (b)(2)(ii)(B), 
in accordance with the alert service bulletin.
    (A) Install a new or serviceable override/jettison pump, and 
repeat the inspection thereafter at intervals not to exceed 10,000 
hours time-in-service after the last inspection. Or
    (B) Reinstall the existing override/jettison pump, and repeat 
the inspection thereafter at intervals not to exceed 1,000 hours 
time-in-service after the last inspection.
    (iii) If the wear to the inlet adapter is greater than or equal 
to 0.60 inch, prior to further flight, install a new or serviceable 
override/jettison pump, in accordance with the alert service 
bulletin. Repeat the inspection thereafter at intervals not to 
exceed 10,000 hours time-in-service after the last inspection.

    Note 2: Boeing Alert Service Bulletin 747-28A2212, Revision 2, 
dated May 14, 1998, includes figures that illustrate specific areas 
to inspect for wear and damage.

    Note 3: Accomplishment of the actions specified in paragraph (b) 
of this AD prior to the effective date of this AD in accordance with 
Revision 1 of Boeing Alert Service Bulletin 747-28A2212, dated April 
23, 1998, is considered acceptable for compliance with paragraph (b) 
of this AD.

    (c) Accomplishment of the actions specified by paragraph (b) of 
this AD constitutes terminating action for the requirements of 
paragraph (a) of this AD. Following accomplishment of those actions, 
the AFM revision may be removed from the AFM.
    (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 appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Seattle ACO.

    Note 4: 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) The actions shall be done in accordance with Boeing Alert 
Service Bulletin 747-28A2212, Revision 2, dated May 14, 1998. 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

[[Page 42213]]

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 August 24, 1998.

    Issued in Renton, Washington, on July 30, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-20969 Filed 8-6-98; 8:45 am]
BILLING CODE 4910-13-U