[Federal Register Volume 64, Number 139 (Wednesday, July 21, 1999)]
[Proposed Rules]
[Pages 39102-39104]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-18628]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-367-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 727-100 and -100C 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 727-100 and -
100C series airplanes. This proposal would require replacement of 
certain skin panels of the lower fuselage with non-bonded skin panels. 
This proposal is prompted by reports of corrosion of the skin panels of 
the lower fuselage on airplanes with hot-bonded doublers. The actions 
specified by the proposed AD are intended to prevent degradation of the 
structural integrity of certain skin panels of the lower fuselage, 
which could result in loss of airplane pressurization.

DATES: Comments must be received by September 7, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-367-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.
    This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Walt Sippel, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2774; fax (425) 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

[[Page 39103]]

must submit a self-addressed, stamped postcard on which the following 
statement is made: ``Comments to Docket Number 98-NM-367-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-114, Attention: Rules 
Docket No. 98-NM-367-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    In 1990, the FAA issued AD 90-06-09, amendment 39-6488 (55 FR 8370, 
March 7, 1990), which required incorporation of certain structural 
modifications on certain Boeing Model 727 series airplanes, in 
accordance with Boeing Document No. D6-54860, Revision C, dated 
December 11, 1989, ``Aging Airplane Service Bulletin Structural 
Modification Program--Model 727.'' One of those modifications was 
replacement of cold-bonded skin panels of the lower fuselage between 
body station (BS) 950 and BS 1183 with non-bonded skin panels. That AD 
was prompted in part by reports of corrosion of the skin panels of the 
lower fuselage on airplanes with cold-bonded doublers and triplers.
    Since the issuance of AD 90-06-09, the FAA has received reports of 
corrosion of the skin panels of the lower fuselage on airplanes with 
hot-bonded doublers. Such corrosion causes degradation of the 
structural integrity of certain skin panels of the lower fuselage, 
which could result in loss of airplane pressurization.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 727-53-
0085, Revision 4, dated July 11, 1991, which describes procedures for 
repetitive inspections of the skin panels of the lower fuselage between 
BS 950 and BS 1183, and repair, if necessary. The service bulletin also 
describes procedures for a modification that involves replacement of 
the skin panels with non-bonded skin panels. Such replacement would 
eliminate the need for the repetitive inspections in that area. 
Accomplishment of the modification specified in the service bulletin is 
intended to adequately address the identified unsafe condition.

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 accomplishment of the actions specified in 
the service bulletin described previously, except as discussed below.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that, although the service bulletin also 
describes procedures for repetitive inspections of certain skin panels 
of the lower fuselage, and repair, if necessary, this AD proposes to 
mandate only the replacement of certain skin panels of the lower 
fuselage with non-bonded skin panels. The repetitive inspections are 
mandated by AD 92-19-10, amendment 39-8368 (57 FR 47404, October 16, 
1992), and the replacement of the skin panels is allowed in that AD as 
an optional terminating action. The FAA has determined that long-term 
continued operational safety will be better assured by modifications or 
design changes to remove the source of the problem, rather than by 
repetitive inspections. Long-term inspections may not be providing the 
degree of safety assurance necessary for the transport airplane fleet. 
This, coupled with a better understanding of the human factors 
associated with numerous repetitive inspections, has led the FAA to 
consider placing less emphasis on special procedures and more emphasis 
on design improvements. The proposed modification requirement is in 
consonance with these considerations.
    Operators should also note that this proposed AD would be 
applicable to only some of the airplanes included in the effectivity 
listing of the service bulletin. AD 90-06-09 mandated the modification 
of certain skin panels of the lower fuselage for airplanes listed in 
Boeing Document No. D6-54860, Revision C, dated December 11, 1989, 
``Aging Airplane Service Bulletin Structural Modification Program--
Model 727.'' The airplanes to which this proposed AD would be 
applicable are included in the effectivity listing of Revision H, dated 
May 9, 1996, of that document.

Cost Impact

    There are approximately 67 airplanes of the affected design in the 
worldwide fleet. Based on a records review, the FAA estimates that only 
38 of those airplanes are still in service. The FAA estimates that 23 
airplanes of U.S. registry still in service would be affected by this 
proposed AD, that it would take approximately 1,216 work hours per 
airplane to accomplish the proposed replacement, and that the average 
labor rate is $60 per work hour. Required parts would cost 
approximately $12,993 per airplane. Based on these figures, the cost 
impact of the proposed AD on U.S. operators is estimated to be 
$1,976,919, or $85,953 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.

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.

[[Page 39104]]

Sec. 39.13  [Amended]

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

Boeing: Docket 98-NM-367-AD.

    Applicability: Model 727-100 and -100C series airplanes; line 
numbers 126, 130, 146, 153, 221, 287, 331, 339, 345, 355, 416, 516, 
532, 540, 551, 555, 559, 575, 592, 594, 596, 599, 600, 604, 605, 
615, 619, 625, 626, 628, 630, 631, 632, 635, 640, 641, 643, 645, 
647, 658, 660, 686, 695, 700, 711, 712, 735, 748, 766, 768, 784, 
797, 803, 806, 810, 812, 817, 821, 822, 824, 829, 854, 856, 857, 
858, 861, and 869; 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 (b) 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 degradation of the structural integrity of certain 
skin panels of the lower fuselage, which could result in loss of 
airplane pressurization, accomplish the following:
    (a) Within 20 years since original installation, or within 4 
years after the effective date of this AD, whichever occurs later, 
replace the skin panels of the lower fuselage between body station 
(BS) 950 and BS 1183 with non-bonded skin panels, in accordance with 
Part VI of the Accomplishment Instructions of Boeing Service 
Bulletin 727-53-0085, Revision 4, dated July 11, 1991.

    Note 2: Accomplishment of the modification specified in Boeing 
Service Bulletin 727-53-0085, Revision 2, dated July 3, 1975, or 
Revision 3, dated September 28, 1989, is acceptable for compliance 
with the replacement required by paragraph (a) of this AD.

    Note 3: Accomplishment of the modification specified in 
paragraph (a) of this AD constitutes terminating action for the 
inspection requirements of AD 92-19-10, amendment 39-8368 (57 FR 
47404, October 16, 1992) for those panels.

Alternative Methods of Compliance

    (b) 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.

Special Flight Permits

    (c) Special flight permits may be issued in accordance with 
Secs. 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 July 15, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-18628 Filed 7-20-99; 8:45 am]
BILLING CODE 4910-13-U