### 65352 Federal Register / Vol. 62, No. 239 / Friday, December 12, 1997 / Rules and Regulations

(c) In the event of loss or damage covered by this policy, we will settle your claim on any unit by:

(1) Multiplying the insured acreage by its respective amount of insurance per acre, by type and variety if applicable;

(2) Totaling the results of section 12(c)(1) if there are more than one type or variety;

(3) Multiplying the total seed production to count (see section 12(d)) for each type and variety of commercial hybrid seed corn by the applicable dollar value per bushel for that type or variety;

(4) Multiplying the total non-seed production to count (see section 12(e)) for each type and variety by the applicable local market price determined on the earlier of the date the non-seed production is sold or the date of final inspection;

(5) Totaling the results of sections 12(c)(3) and 12(c)(4) by type and variety;

(6) Subtracting the result of section 12(c)(5) from the result of section 12(c)(1) if there is only one type or variety, or subtracting the result of 1or variety; and

(7) Multiplying the result of section 12(c)(6) by your share. For example:

You have a 100 percent share in 50 acres insured for the development of variety ‘‘A’’ hybrid seed corn in the unit, with an amount of insurance per acre guarantee of $340 (county yield of 160 bushels times a coverage level factor of .867 for the 65 percent coverage level, times a price election of $2.45 per bushel, minus the minimum guaranteed payment of zero). Your seed production was 1,400 bushels and the dollar value per bushel was $9.80. Your non-seed production was
100 bushels with a local market value of $2.00 per bushel. Your indemnity would be
calculated as follows:

(1) 50 acres × $340=$17,000 amount of insurance guarantee;

(3) 1,400 bushels × $9.80=$13,720 value of seed production;

(4) 100 bushel of non-seed× $2.00=$200 of non-seed production;

(5) $13,720+$200=$13,920; (6) $17,000

¥ $13,920=$3,080; and (7) $3,080 × 100 percent share=$3,080 indemnity payment.

You also have a 100 percent share in 50 acres insured for the development of variety ‘‘B’’ hybrid seed corn in the unit, with an amount of insurance per acre guarantee of $297 (county yield of 140 bushels times a coverage level factor of .867 for the 65 percent coverage level, times a price election of $2.45 per bushel, minus the minimum guaranteed payment of zero). You harvested 1,200 bushels and the dollar value per bushel
for the harvested amount was $8.56. You also
harvested 200 bushels of non-seed with a market value of $2.00 per bushel. Your indemnity would be calculated as follows:

(1) 50 acres × $340=$17,000 amount of insurance guarantee for type ‘‘A’’ and 50

acres × $297=$14,850 amount of insurance guarantee for type ‘‘B’’;

(2) $17,000+$14,850=$31,850 amount of insurance guarantee;

(3) 1,400 bushels × $9.80=$13,720 value of seed production for type ‘‘A’’ and 1,200
bushels × $8.56=$10,272 value of seed production for type ‘‘B’’;

(4) 100 bushels of non-seed× $2.00=$200 of non-seed production for type ‘‘A’’ and 200 bushels of non-seed× $2.00=$400 of non-seed production for type ‘‘B’’;

(5) $13,720+$200+$10,272+$400=$24,592 value of production to count;

(6) $31,850

¥ $24,592=$7,258; and (7) $7,258 × 100 percent share=$7,258 indemnity payment.

(d) Production to be counted as seed production will include:

(1) All appraised production as follows: (i) Not less than the amount of insurance per acre for acreage:

(A) That is abandoned; (B) Put to another use without our consent; (C) That is damaged solely by uninsured

causes; or

(D) For which you fail to provide acceptable production records;

(ii) Production lost due to uninsured

causes;

(iii) Mature unharvested production with a germination rate of at least 80 percent of the commercial hybrid seed corn as determined by a certified seed test. Any such production may be adjusted in accordance with section 12(f);

(iv) Immature appraised production; (v) Potential production on insured acreage that you intend to put to another use or abandon, if you and we agree on the appraised amount of production. Upon such agreement, the insurance period for that acreage will end when you put the acreage to another use or abandon the crop. If agreement on the appraised amount of production is not reached:

(A) If you do not elect to continue to care for the crop, we may give you consent to put the acreage to another use if you agree to leave intact, and provide sufficient care for, representative samples of the crop in locations acceptable to us (The amount of production to count for such acreage will be based on the harvested production or appraisals from the samples at the time harvest should have occurred. If you do not leave the required samples intact, or fail to provide sufficient care for the samples, our appraisal made prior to giving you consent to put the acreage to another use will be used to determine the amount of production to count); or

(B) If you elect to continue to care for the crop, the amount of production to count for the acreage will be the harvested production, or our reappraisal if additional damage occurs and the crop is not harvested; and

(2) Harvested production that you deliver as commercial hybrid seed corn to the seed company stated in your hybrid seed corn processor contract, regardless of quality, unless the production has inadequate germination.

(e) Production to be counted as non-seed production will include all harvested or mature appraised production that does not qualify as seed production to count as specified in section 12(d). Any such production may be adjusted in accordance with section 12(f).

(f) For the purpose of determining the quantity of mature production:

(1) Shelled commercial hybrid seed corn
will be:

(i) Increased 0.12 percent for each 0.1 percentage point of moisture below 15
percent; or (ii) Decreased 0.12 percent for each 0.1 percentage point of moisture in excess of 15
percent.

(2) The weight of ear corn required to equal

one bushel of shelled seed corn will be increased 1.5 pounds for each full percentage point of moisture in excess of 14 percent, and any portion of a percentage point will be disregarded. The moisture content of ear corn will be determined from a shelled sample of

the ear corn.

(3) When records of commercial hybrid seed corn production provided by the seed company have been adjusted to a shelled corn basis of 15.0 percent moisture and 56 pound avoirdupois bushels, sections 12(f)(1) and (2) above will not apply to harvested production. In such cases, records of the seed company will be used to determine the amount of production to count, provided that the moisture and weight of such production

are calculated on the same basis as that used to determine the approved yield.

13. Prevented Planting. Your prevented planting coverage will be 50 percent of your amount of insurance for timely planted acreage. If you have limited or additional levels of coverage as specified in 7 CFR part 400, subpart T, and pay an additional premium, you may increase your prevented planting coverage to a level specified in the actuarial documents.

Signed in Washington, D.C., on December
5, 1997.

Kenneth D. Ackerman,
Manager, Federal Crop Insurance Corporation.

[FR Doc. 97–32498 Filed 12–11–97; 8:45 am]

BILLING CODE 3410–08–P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97–NM–295–AD; Amendment 39–10250; AD 97–26–07]

RIN 2120–AA64

Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION : Final rule; request for

comments.

SUMMARY : This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that currently requires a one-time inspection to detect damage of the sleeving and wire bundles of the boost pumps of the numbers 1 and 4 main fuel tanks, and of the auxiliary tank jettison pumps (if installed); replacement of any damaged sleeving with new sleeving; and repair or replacement of any damaged wires with new wires. For airplanes on which any

### 65353 Federal Register / Vol. 62, No. 239 / Friday, December 12, 1997 / Rules and Regulations

burned wires are found, that AD also requires an inspection to detect damage of the conduit, and replacement of any damaged conduit with a serviceable conduit. This amendment requiresrepetitive inspections in lieu of the onetime inspection. This amendment also expands the applicability of the existing AD. This amendment is prompted by reports of chafing of the sleeving. The actions specified in this AD are
intended to detect and correct abrasion of the Teflon sleeving and wires in the bundles of the fuel boost pumps for the
numbers 1 and 4 main fuel tanks and of the auxiliary tank jettison pumps (if installed), which could result in electrical arcing between the wires and the aluminum conduit and consequent fire or explosion of the fuel tank.

DATES : Effective December 29, 1997.

The incorporation by reference of Boeing Service Bulletin 747–28A2204, Revision 1, dated October 30, 1997, as listed in the regulations, is approved by the Director of the Federal Register as of December 29, 1997.

The incorporation by reference of Boeing Alert Service Bulletin 747– 28A2204, dated December 19, 1996, as listed in the regulations, was approved previously by the Director of the Federal Register as of January 21, 1997 (62 FR 304, January 3, 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–114,
Attention: Rules Docket No. 97-NM– 295–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: Ed Hormel, Aerospace Engineer, Propulsion Branch, ANM–140S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055–4056; telephone (425) 227–2681; fax (425) 227–1181.

SUPPLEMENTARY INFORMATION : On December 23, 1996, the FAA issued AD 96–26–06, amendment 39–9870 (62 FR 304, January 3, 1997), applicable to certain Boeing Model 747 series airplanes, to require a one-time inspection to detect damage of the sleeving and wire bundles of the boost pumps of the numbers 1 and 4 main fuel tanks, and of the auxiliary tank jettison pumps (if installed); replacement of any damaged sleeving with new sleeving; and repair or replacement of any damaged wires with new wires. For airplanes on which any burned wires are found, that AD also requires an inspection to detect damage of the conduit, and replacement of any damaged conduit with a serviceable conduit. That action was prompted by
an FAA determination that an
environment conducive to vibration
exists in the conduit and wire bundles of the boost pumps and of the auxiliary tank jettison pumps, which can cause abrasion of the Teflon sleeving and consequent abrasion of the wires in the bundles. The actions required by that
AD are intended to detect and correct such abrasion, which could result in electrical arcing between the wires and the aluminum conduit and consequent fire or explosion of the fuel tank.

Actions Since Issuance of Previous Rule

Since the issuance of AD 96–26–06, the FAA has received numerous reports of chafing through the outer Teflon
sleeve of the wire bundles of the boost pumps of the numbers 1 and 4 main fuel tanks. Several of the sleeves had large holes. No cases of wire chafing through
the insulation to the conductor were reported. Investigation revealed that two of the affected operators had varying levels of chafing with damage on 48 percent of their airplanes. Both of these operators had replaced the aluminum
conduits with stainless steel conduits. Other affected operators’ airplanes (with flight hour totals similar to those of the airplanes discussed previously) that were equipped with aluminum conduits had a much lower incidence of reported damage.

At the time of issuance of AD 96–26– 06, the FAA considered the aluminum conduit to be more susceptible to chafing and burning as a result of electrical arcing between the wires and
the aluminum conduit than the stainless steel conduit. Therefore, the FAA limited the inspection required by AD 96–26–06 to Boeing Model 747 series airplanes equipped with aluminum conduits (line numbers 001 through 432 inclusive).

In light of these new findings, the FAA has determined that Boeing Model 747 series airplanes equipped with stainless steel conduits are subject to the
same unsafe condition addressed in AD 96–26–06. In addition, the FAA finds that, regardless of the conduit material, repetitive inspections are necessary to determine if the sleeving of the wire bundles continues to provide a protective barrier after extended time in

service.

Explanation of Relevant Service
Information

Additionally, since the issuance of AD 96–26–06, the FAA has reviewed and approved Revision 1 of Boeing Service Bulletin 747–28A2204, dated October 30, 1997. Revision 1 of the service bulletin revises the effectivity listing of the original version of the service bulletin (which was referenced in AD 96–26–06 as the appropriate source of service information) by adding Boeing Model 747 series airplanes having line numbers 433 through 1120 inclusive. The inspection and corrective procedures described in Revision 1 are essentially identical to those described in the original version of the alert
service bulletin.

Explanation of Requirements of Rule

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of this same type design, this AD supersedes AD 96– 26–06 to require repetitive inspections,in lieu of the previously required onetime inspection, to detect damage of the sleeving and wire bundles of the boost pumps of the numbers 1 and 4 main fuel tanks, and of the auxiliary tank jettison pumps (if installed); replacement of any damaged sleeving with new sleeving; and repair or replacement of any damaged wires with new wires. For airplanes on which any burned wires are found, this AD also continues to require an inspection to detect damage of the conduit, and replacement of any damaged conduit with a serviceable conduit. This AD also expands the applicability of the existing AD to include additional airplanes. This AD requires that operators submit a report to the FAA of any damage found as a result of the initial inspection.

Differences Between the AD and the
Relevant Service Information

Operators should note that the applicability of the AD differs from the effectivity listing of Revision 1 of the
referenced service bulletin. The FAA has determined that all Boeing Model 747 series airplanes are subject to the
addressed unsafe condition.

Interim Action

This is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking.

### 65354 Federal Register / Vol. 62, No. 239 / Friday, December 12, 1997 / Rules and Regulations

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–295–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 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.

§ 39.13 [Amended]

2. Section 39.13 is amended by removing amendment 39–9870 (62 FR 304, January 3, 1997), and by adding a new airworthiness directive (AD), amendment 39–10250, to read as
follows:

97–26–07 Boeing: Amendment 39–10250. Docket 97–NM–295–AD. Supersedes AD 96–26–06, Amendment 39–9870.
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 (h) 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 abrasion of the Teflon sleeving and wires in the bundles of the fuel boost pumps for the numbers 1 and 4 main fuel tanks and of the auxiliary tank jettison pumps (if installed), which could result in electrical arcing between the wires and the aluminum conduit and consequent fire or explosion of the fuel tank, accomplish the following:

(a) Perform an initial inspection to detect damage of the sleeving and wire bundles of the forward and aft boost pumps of the numbers 1 and 4 main fuel tanks, and of the wire bundles of the auxiliary tank jettison pumps (if installed), in accordance with Boeing Alert Service Bulletin 747–28A2204, dated December 19, 1996, or Boeing Service Bulletin 747–28A2204, Revision 1, dated October 30, 1997, at the time specified in paragraph (a)(1) or (a)(2) of this AD, as applicable.

(1) For airplanes having line numbers 001 through 432 inclusive: Inspect within 120 days after January 21, 1997 (the effective date of AD 96–26–06, amendment 39–9870).

(2) For airplanes having line numbers 433 and subsequent: Inspect at the later of the times specified in paragraphs (a)(2)(i) and (a)(2)(ii) of this AD.

(i) Prior to the accumulation of 20,000 flight cycles or 60,000 flight hours, whichever occurs first; or

(ii) Within 120 days after the effective date

of this AD.

(b) Repeat the inspection required by paragraph (a) of this AD at intervals not to exceed 20,000 flight cycles or 60,000 flight hours since the last inspection, whichever

occurs first.

(c) If any damaged sleeving is found, prior to further flight, replace the sleeving with new sleeving in accordance with Boeing Alert Service Bulletin 747–28A2204, dated December 19, 1996, or Boeing Service Bulletin 747–28A2204, Revision 1, dated October 30, 1997.

(d) If any damaged wire is found, prior to further flight, repair or replace the wire with a new wire in accordance with Boeing Alert Service Bulletin 747–28A2204, dated December 19, 1996, or Boeing Service Bulletin 747–28A2204, Revision 1, dated October 30, 1997.

(e) If any burned wire is found, prior to further flight, perform an inspection to detect damage of the conduit, in accordance with Boeing Alert Service Bulletin 747–28A2204, dated December 19, 1996, or Boeing Service Bulletin 747–28A2204, Revision 1, dated October 30, 1997. If any damage is found, prior to further flight, replace the conduit

with a serviceable conduit in accordance

with either of the service bulletins. After the effective date of this AD, only Revision 1 of

this service bulletin shall be used.

(f) For airplanes having line numbers 433 and subsequent: Within 14 days after accomplishing the initial inspection required by paragraph (a) of this AD, submit a report of any damaged sleeving (i.e., holes, breaks, cuts, splits), damaged wire (i.e., worn or cracked insulation, exposed conductor, indication of arcing/burning), or damaged conduit to the Manager, Seattle Aircraft

### 65355 Federal Register / Vol. 62, No. 239 / Friday, December 12, 1997 / Rules and Regulations

Certification Office (ACO), FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, WA 98055–4056; fax (425) 227– 1181. The report shall include the information specified in paragraphs (f)(1), (f)(2), (f)(3), (f)(4), and (f)(5) of this AD. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C.

3501 et seq. ) and have been assigned OMB
Control Number 2120–0056.

(1) The airplane serial number. (2) The total hours time-in-service accumulated on the airplane.

(3) The total number of flight cycles accumulated on the airplane.

(4) A description of any damage found. (5) The location of where the damaged part
was installed.

(g) For airplanes having line numbers 433 and subsequent: Within 14 days after accomplishing the initial inspection required by paragraph (a) of this AD, submit any damaged part to the Manager, Seattle ACO. The damaged part shall be tagged to include the information specified in paragraphs (f)(1), (f)(2), (f)(3), (f)(4), and (f)(5) of this AD. Additionally, operators shall align the inner sleeving, outer sleeving, and wire as installed in the airplane, and secure the sleeving and wiring in place by taping or other means when submitting the damaged part to the Manager, Seattle ACO. Information collection requirements contained in this regulation have been approved by the OMB under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq. ) and have been assigned OMB Control Number 2120–0056.

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

(i) 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.

(j) The actions shall be done in accordance with Boeing Alert Service Bulletin 747– 28A2204, dated December 19, 1996, or Boeing Service Bulletin 747–28A2204, Revision 1, dated October 30, 1997.

(1) The incorporation by reference of Boeing Service Bulletin 747–28A2204, Revision 1, dated October 30, 1997, is approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

(2) The incorporation by reference of Boeing Alert Service Bulletin 747–28A2204, dated December 19, 1996, was approved previously by the Director of the Federal Register as of January 21, 1997 (62 FR 304, January 3, 1997). (3) 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.

(k) This amendment becomes effective on December 29, 1997.

Issued in Renton, Washington, on December 9, 1997.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 97–32611 Filed 12–11–97; 8:45 am]

BILLING CODE 4910–13–P

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.

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