[Federal Register Volume 62, Number 239 (Friday, December 12, 1997)]
[Rules and Regulations]
[Pages 65355-65357]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-32233]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-282-AD; Amendment 39-10239; AD 97-25-15]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 727 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 certain Boeing Model 727 series airplanes. This action 
requires repetitive inspections to detect cracking of the rear spar web 
or fuel leakage of the wing center section, and repair, if necessary. 
This amendment also provides for an optional modification of the rear 
spar web that constitutes terminating action for the repetitive 
inspections. This amendment is prompted by several reports of fuel 
leakage due to cracking of the rear spar web of the wing center 
section. The actions specified in this AD are intended to detect and 
correct such cracking of the rear spar web, which could permit fuel 
leakage into the airflow multiplier, and could result in an electrical 
short that could cause a fire.

DATES: Effective December 29, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of December 29, 1997.
    Comments for inclusion in the Rules Docket must be received on or 
before February 10, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-282-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: Walter Sippel, Aerospace Engineer, 
Airframe Branch, ANM-120S, Seattle Aircraft Certification Office, FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2774; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: The FAA has received reports indicating that 
fuel leakage of the wing center section has occurred on several Boeing 
Model 727 series airplanes due to cracking of the rear spar web of the 
wing center section. The cracking initiates on the forward side of the 
spar and propagates through the web at the upper machined land radius 
between Left Body Buttock Line (BBL) 40 and Right BBL 40. In two 
instances, cracking was reported on airplanes that had accumulated less 
than 25,000 total flight cycles. In another case, fuel leakage resulted 
in fuel odors being emitted into the cabin area. Investigation revealed 
that fuel was leaking into the airflow multiplier. Fuel leakage into 
the airflow multiplier due to cracking of the rear spar web of the wing 
center section, if not detected and corrected, could result in an 
electrical short that could cause a fire.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
727-57A0182, dated September 18, 1997. This alert service bulletin 
describes procedures for removing the access panels of the wing center 
section to perform repetitive visual inspections using a borescope, or 
ultrasonic with high frequency eddy current inspections, to detect 
cracking of the rear spar web or fuel leakage of the wing center 
section, and repair, if necessary.
    In addition, the alert service bulletin describes procedures for 
modification of the rear spar web of the wing center section to prevent 
cracking of the rear spar web, which eliminates the need for the 
repetitive inspections the modification involves stop drilling any

[[Page 65356]]

cracking, and repairing the rear spar web.
    The alert service bulletin references Boeing Drawing 65C37620 as an 
additional source of service information for accomplishment of the 
repair and modification.

Explanation of the Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other Boeing Model 727 series airplanes of the same 
type design, this AD is being issued to detect and correct cracking of 
the rear spar web, which could permit fuel leakage into the airflow 
multiplier and resultant electrical shorting and fire. This AD requires 
repetitive inspections [either visual inspections using a borescope or 
a mirror, or ultrasonic and high frequency eddy current (HFEC) 
inspections] to detect cracking of the rear spar web or fuel leakage of 
the wing center section, and repair, if necessary. This AD also 
provides for an optional modification of the rear spar web of the wing 
center section, which constitutes terminating action for the repetitive 
inspection requirements of this AD. The inspections, certain repairs, 
and the modification are required to be accomplished in accordance with 
the alert service bulletin described previously. Certain repairs are 
required to be accomplished in accordance with a method approved by the 
FAA.
    Operators should note the following differences between this AD and 
the Boeing alert service bulletin:
     Although the alert service bulletin recommends an initial 
inspection threshold of within 500 flight cycles for airplanes that 
have accumulated between 15,000 and 25,000 total flight cycles, and an 
initial inspection threshold of within 300 flight cycles for airplanes 
that have accumulated 25,000 or more total flight cycles, this AD 
specifies an initial compliance time of ``prior to the accumulation of 
15,000 total flight cycles, or within 300 flight cycles after the 
effective date of this AD, whichever occurs later.'' The FAA finds 
that, in view of the reports of cracking of the rear spar web on two 
airplanes that had accumulated less than 25,000 total flight cycles, 
the initial compliance time specified in this AD is appropriate. 
Further, the FAA finds that adequate justification for permitting an 
inspection threshold of 500 flight cycles for airplanes that have 
accumulated over 15,000 total flight cycles, but under 25,000 total 
flight cycles, has not been presented. Therefore, an initial inspection 
is required to be accomplished on all airplanes within 300 flight 
cycles after the effective date of this AD.
     This AD requires that, for any cracking or fuel leakage 
detected that is outside the areas specified in the alert service 
bulletin, repair must be accomplished in accordance with a method 
approved by the FAA.
     This AD requires that the access panel only be opened in 
order to perform the inspections, rather than removed, as described in 
the Boeing alert service bulletin. The manufacturer has advised the FAA 
that procedures to remove the access panels were inadvertently included 
in the alert service bulletin and will be removed at the next revision 
of the alert service bulletin.
     Although the alert service bulletin describes procedures 
for performing the visual inspection using a borescope, the 
manufacturer has advised the FAA that the option of performing the 
visual inspection using a mirror was inadvertently omitted from the 
alert service bulletin. Moreover, Figure 1 of the Accomplishment 
Instructions of the alert service bulletin specifies that the subject 
area can be examined with a borescope or mirror. Therefore, the FAA has 
included the option of using a mirror as an acceptable method of 
compliance with the visual inspection requirements of this AD.

Interim Action

    This is considered to be interim action. The FAA is currently 
considering requiring the modification of the rear spar web of the wing 
center section, which will constitute terminating action for the 
repetitive inspections required by this AD. However, the planned 
compliance time for the installation of the modification is 
sufficiently long so that notice and opportunity for prior public 
comment will be practicable.

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 97-NM-282-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, 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

[[Page 65357]]

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:

97-25-15  Boeing: Amendment 39-10239. Docket 97-NM-282-AD.

    Applicability: Model 727 series airplanes having line numbers 
858 through 864 inclusive, 867 through 869 inclusive, 872 through 
883 inclusive, and 885 through 1832 inclusive; 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 (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 rear spar web, which could 
permit fuel leakage into the airflow multiplier, and could result in 
an electrical short that could cause a fire, accomplish the 
following:
    (a) Prior to the accumulation of 15,000 total flight cycles, or 
within 300 flight cycles after the effective date of this AD, 
whichever occurs later: Accomplish the inspections specified in 
either paragraph (a)(1) or (a)(2) of this AD, in accordance with 
Boeing Alert Service Bulletin 727-57A0182, dated September 18, 1997. 
For purposes of this AD, the access panels specified in the alert 
service bulletin need not be removed; the access panels need only be 
opened.

    Note 2: The fuel tank of the wing center section may be filled 
with fuel to assist in detecting cracking or fuel leakage during the 
accomplishment of the visual inspections required by this AD.

    (1) Perform a visual inspection using a borescope or mirror to 
detect cracking of the rear spar web and/or fuel leakage of the wing 
center section between Right Body Buttock Line (BBL) 40 and Left BBL 
40, in accordance with Part I of the Accomplishment Instructions of 
the alert service bulletin. Thereafter, repeat this inspection at 
intervals not to exceed 300 flight cycles. Or
    (2) Perform an ultrasonic and high frequency eddy current (HFEC) 
inspection to detect cracking of the rear spar web of the wing 
center section between Right BBL 40 and Left BBL 40, in accordance 
with Part II of the Accomplishment Instructions of the alert service 
bulletin. Thereafter, repeat this inspection at intervals not to 
exceed 3,000 flight cycles.
    (b) If any cracking of the rear spar web and/or fuel leakage of 
the wing center section is detected between Right BBL 40 and Left 
BBL 40 near the upper machined land radius, prior to further flight, 
repair in accordance with Part III of the Accomplishment 
Instructions in Boeing Alert Service Bulletin 727-57A0182, dated 
September 18, 1997. Accomplishment of this repair constitutes 
terminating action for the repetitive inspection requirements of 
this AD.
    (c) If any cracking of the rear spar web and/or fuel leakage of 
the wing center section is detected that is outside the area 
specified in paragraph (b) of this AD, prior to further flight, 
repair in accordance with a method approved by the Manager, Seattle 
Aircraft Certification Office (ACO), FAA, Transport Airplane 
Directorate.
    (d) Accomplishment of paragraphs (d)(1) and either (d)(2) or 
(d)(3) of this AD, as applicable, constitute terminating action for 
the repetitive inspection requirements of this AD.
    (1) Accomplish an ultrasonic and HFEC inspection in accordance 
with the requirements of paragraph (a)(2) of this AD. And,
    (2) If no cracking is detected, prior to further flight, modify 
the rear spar web of the center section of the fuel tank between 
Right BBL 40 and Left BBL 40, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 727-57A0182, dated 
September 18, 1997.
    (3) If any cracking is detected, prior to further flight, repair 
in accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 727-57A0182, dated September 18, 1997.
    (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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Manager, Seattle ACO.

    (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, provided the 
limitations specified in paragraphs (f)(1) through (f)(6) of this AD 
are included in the special flight permit:
    ``(1) Required trip and reserve fuel must be carried in the No. 
1 and No. 3 outer wing tanks.
    (2) Wing center tank No. 2 must be empty of fuel.
    (3) The fuel system must be checked for normal operation prior 
to flight by verifying that all boost pumps are operational; 
configuring the fuel system by turning on all boost pumps in the No. 
1 and 3 outer wing tanks and by opening all crossfeed valve 
selectors; and by confirming that fuel is not bypassing tank No. 2 
check valves by observing that there is no leakage into tank No. 2.
    (4) Maintain a minimum of 5,300 pounds of fuel in tanks No. 1 
and No. 3 to prevent uncovering the fuel bypass valve.
    (5) The fuel quantity indication system must be operational in 
all three tanks.
    (6) The effects of loading fuel only in the wing tanks on the 
airplane weight and balance must be considered and accounted for.''
    (g) Except as provided by paragraph (c) of this AD, the actions 
shall be done in accordance with Boeing Alert Service Bulletin 727-
57A0182, dated September 18, 1997. 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.
    (h) This amendment becomes effective on December 29, 1997.

    Issued in Renton, Washington, on December 3, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-32233 Filed 12-11-97; 8:45 am]
BILLING CODE 4910-13-P