[Federal Register Volume 64, Number 4 (Thursday, January 7, 1999)]
[Rules and Regulations]
[Pages 987-989]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-184]



[[Page 987]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-264-AD; Amendment 39-10984; AD 98-11-04 R1]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-100 and -200 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; correction.

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SUMMARY: This amendment corrects information in an existing 
airworthiness directive (AD), applicable to all Boeing Model 737-100 
and -200 series airplanes, that currently requires that the FAA-
approved maintenance inspection program be revised to include 
inspections that will give no less than the required damage tolerance 
rating for each Structural Significant Item, and repair of cracked 
structure. The actions specified in that AD are intended to ensure the 
continued structural integrity of the entire Boeing Model 737-100 and -
200 fleet. This amendment corrects the requirements of the current AD 
by allowing operators not to change their programs if they determine 
that the existing inspections are effective for the new or affected 
SSI. This amendment is prompted by a review of the requirements of the 
existing AD.

DATES: Effective June 23, 1998.
    The incorporation by reference of certain publications listed in 
the regulations was approved previously by the Director of the Federal 
Register as of June 23, 1998 (63 FR 27465, May 19, 1998).

FOR FURTHER INFORMATION CONTACT: Greg Schneider, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Washington; telephone (425) 227-2028; fax (425) 
227-1181.

SUPPLEMENTARY INFORMATION: On May 12, 1998, the FAA issued AD 98-11-04, 
amendment 39-10531 (63 FR 27465, May 19, 1998), which is applicable to 
all Boeing Model 737-100 and -200 series airplanes. That AD requires 
that the FAA-approved maintenance inspection program be revised to 
include inspections that will give no less than the required damage 
tolerance rating for each Structural Significant Item (SSI), and repair 
of cracked structure. That action was prompted by a structural re-
evaluation by the manufacturer which identified additional structural 
elements where, if damage were to occur, supplemental inspections may 
be required for timely detection. The actions required by that AD are 
intended to ensure the continued structural integrity of the entire 
Boeing Model 737-100 and -200 fleet.
    AD 98-11-04 contains provisions regarding when operators must 
revise their maintenance or inspection program to address SSI's that 
are created or affected by repairs and design changes. As discussed in 
the preamble to the final rule, the FAA intended that such revisions be 
made only if a damage tolerance assessment indicates that such a change 
is necessary because existing inspections are ineffective for the SSI. 
Paragraph (d)(1) of the AD, applicable to repairs and design changes 
accomplished prior to the effective date of the AD, properly states the 
FAA's intent. However, the FAA inadvertently omitted a comparable 
provision in paragraph (g), which applies to repairs and design changes 
accomplished after the effective date of the AD. As adopted, paragraph 
(g) requires that operators revise their maintenance programs following 
repairs and design changes, regardless of whether a damage tolerance 
assessment indicates that the existing applicable inspection continue 
to be effective. Therefore, consistent with the FAA's intent, this 
correction is necessary to allow operators not to change their programs 
if they determine that the existing inspections are effective for the 
new or affected SSI.
    Action is taken herein to correct these requirements of AD 98-11-04 
and to correctly add the AD as an amendment to section 39.13 of the 
Federal Aviation Regulations (14 CFR 39.13).
    The final rule is being reprinted in its entirety for the 
convenience of affected operators. The effective date remains June 23, 
1998.
    Since this action only corrects a current requirement, it has no 
adverse economic impact and imposes no additional burden on any person. 
Therefore, notice and public procedures hereon are unnecessary.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Correction

    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 removing amendment 39-10531 (63 FR 
27465, May 19, 1998), and by adding a new airworthiness directive (AD), 
amendment 39-10984, to read as follows:

98-11-04 R1  Boeing: Amendment 39-10984. Docket 96-NM-264-AD. 
Revises AD 98-11-04, Amendment 39-10531.

    Applicability: All Model 737-100 and -200 series airplanes 
(including Model 737-200C series airplanes), certificated in any 
category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To ensure the continued structural integrity of the entire 
Boeing Model 737-100 and -200 fleet:

    Note 1: Where there are differences between the AD and the 
Supplemental Structural Inspection Document, the AD prevails.

    (a) For airplanes listed in Section 3.0 of Boeing Document No. 
D6-37089, ``Supplemental Structural Inspection Document'' (SSID), 
Revision B, dated February 18, 1987, and Revision C, dated January 
1990: Within 12 months after August 9, 1991 (the effective date of 
AD 91-14-20, amendment 39-7061), incorporate a revision into the 
FAA-approved maintenance inspection program which provides no less 
than the required damage tolerance rating (DTR) for each Structural 
Significant Item (SSI) listed in that document. (The required DTR 
value for each SSI is listed in the document.) The revision to the 
maintenance program shall include and shall be implemented in 
accordance with the procedures in Sections 5.0 and 6.0 of the SSID. 
This revision shall be deleted following accomplishment of the 
requirements of paragraph (b) of this AD.

    Note 2: For the purposes of this AD, an SSI is defined as a 
principal structural element that could fail and consequently reduce 
the structural integrity of the airplane.

    (b) Prior to reaching the threshold specified in paragraph (c) 
of this AD, or within 12 months after the effective date of this AD, 
whichever occurs later, incorporate a revision into the FAA-approved 
maintenance or inspection program that provides no less than the 
required DTR for each SSI listed in Boeing Document No. D6-37089, 
``Supplemental Structural Inspection Document'' (SSID), Revision D, 
dated June 1995 (hereinafter referred to as ``Revision D''). (The 
required DTR value for each SSI is listed in the document.) Except 
as provided to the contrary in paragraphs (c), (d), and (g) of this 
AD, the revision to the maintenance or inspection program shall 
include and shall be implemented in accordance with the procedures 
in Section 5.0, ``Damage Tolerance Rating (DTR) System Application''

[[Page 988]]

and Section 6.0, ``SSI Discrepancy Reporting'' of Revision D. Upon 
incorporation of the revision required by this paragraph, the 
revision required by paragraph (a) of this AD may be deleted.
    (c) Except as provided in paragraph (d), (e), or (g) of this AD, 
perform an inspection to detect cracks in all structure identified 
in Revision D at the time specified in paragraph (c)(1) or (c)(2) of 
this AD, as applicable.
    (1) For Model 737-200C series airplanes: Inspect prior to the 
accumulation of 46,000 total flight cycles, or within 4,000 flight 
cycles measured from the date 12 months after the effective date of 
this AD, whichever occurs later.

    Note 3: The requirements specified in paragraph (c)(1) of this 
AD only apply to airplanes listed as 737-200C on the type 
certificate data sheet. Paragraph (c)(1) does not apply to airplanes 
that have been modified from a passenger configuration to an all-
cargo configuration by supplemental type certificate (STC). 
Paragraphs (c)(2) and (d) apply to those airplanes.

    (2) For all airplanes, except for those airplanes identified in 
paragraph (c)(1) of this AD: Inspect prior to the accumulation of 
66,000 total flight cycles, or within 4,000 flight cycles measured 
from the date 12 months after the effective date of this AD, 
whichever occurs later.

    Note 4: Notwithstanding the provisions of paragraphs 5.1.1, 
5.1.2, 5.1.6(e), 5.1.11, 5.1.12, 5.1.13, 5.2, 5.2.1, 5.2.2, 5.2.3, 
and 5.2.4 of the General Instructions of Revision D, which would 
permit operators to perform fleet and rotational sampling 
inspections, to perform inspections on less than whole airplane 
fleet sizes and to perform inspections on substitute airplanes, this 
AD requires that all airplanes that exceed the threshold be 
inspected in accordance with Revision D.
    Note 5: Once the initial inspection has been performed, 
operators are required to perform repetitive inspections at the 
intervals specified in Revision D in order to remain in compliance 
with their maintenance or inspection programs, as revised in 
accordance with paragraph (b) of this AD.

    (d) For airplanes on which the structure identified in Revision 
D has been physically altered in accordance with an STC prior to the 
effective date of this AD: Accomplish the requirements specified in 
paragraph (d)(1) or (d)(2) of this AD.
    (1) Within 18 months after the effective date of this AD, assess 
the damage tolerance characteristics of each SSI created or affected 
by each STC to determine the effectiveness of the applicable 
Revision D inspection for each SSI and, if not effective, revise the 
FAA-approved maintenance or inspection program to include an 
inspection method for each new or affected SSI, and to include the 
compliance times for initial and repetitive accomplishment of each 
inspection. Following accomplishment of the revision and within the 
compliance times established, perform an inspection to detect cracks 
in the structure affected by any design change or repair, in 
accordance with the new inspection method. The new inspection method 
and the compliance times shall be approved by the Manager, Seattle 
Aircraft Certification Office (ACO), FAA, Transport Airplane 
Directorate.

    Note 6: For purposes of this AD, an SSI is ``affected'' if it 
has been physically altered or repaired, or if the loads acting on 
the SSI have been increased or redistributed. The effectiveness of 
the applicable inspection method and compliance time should be 
determined based on a damage tolerance assessment methodology, such 
as that described in FAA Advisory Circular AC No. 91-56, Change 2, 
dated April 15, 1983.

    (2) Accomplish paragraphs (d)(2)(i), (d)(2)(ii), and (d)(2)(iii) 
of this AD.
    (i) Within 18 months after the effective date of this AD, submit 
a plan that describes a methodology for accomplishing the 
requirements of paragraph (d)(1) of this AD to the Manager, Seattle 
ACO, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; fax (425) 
227-1181.

    Note 7: The plan should include a detailed description of the: 
STC; methodology for identifying new or affected SSI's; method for 
developing loads and validating the analysis; methodology for 
evaluating and analyzing the damage tolerance characteristics of 
each new or affected SSI; and proposed inspection method. The plan 
would not need to include all of these elements if the operator can 
otherwise demonstrate that its plan will enable the operator to 
comply with paragraph (d)(2)(iii) of this AD.

    (ii) Within 18 months after the effective date of this AD, 
perform a detailed visual inspection in accordance with a method 
approved by the Manager, Seattle ACO to detect cracks in all 
structure identified in Revision D that has been altered by an STC.
    (A) If no crack is detected, repeat the detailed visual 
inspection thereafter at intervals not to exceed 18 months.
    (B) If any crack is detected, prior to further flight, repair it 
in accordance with a method approved by the Manager, Seattle ACO.
    (iii) Within 48 months after the effective date of this AD, 
revise the FAA-approved maintenance or inspection program to include 
an inspection method for each new or affected SSI, and to include 
the compliance times for initial and repetitive accomplishment of 
each inspection. The inspection methods and the compliance times 
shall be approved by the Manager, Seattle ACO. Accomplishment of the 
actions specified in this paragraph constitutes terminating action 
for the repetitive inspection requirements of paragraph 
(d)(2)(ii)(A) of this AD.

    Note 8: Notwithstanding the provisions of paragraphs 5.1.17 and 
5.1.18 of the General Instructions of Revision D, which would permit 
deletions of modified, altered, or repaired structure from the SSIP, 
the inspection of SSI's that are modified, altered, or repaired 
shall be done in accordance with a method approved by the Manager, 
Seattle ACO.

    (e) For airplanes on which the structure identified in Revision 
D has been repaired or physically altered by any design change other 
than an STC identified in paragraph (d), prior to the effective date 
of this AD: At the time of the first inspection of each SSI after 
the effective date of this AD in accordance with Revision D, 
identify each repair or design change to that SSI. Within 12 months 
after such identification, assess the damage tolerance 
characteristics of each SSI created or affected by each repair or 
design change to determine the effectiveness of the applicable SSID 
inspection for each SSI and, if not effective, revise the FAA-
approved maintenance or inspection program to include an inspection 
method and compliance times for each new or affected SSI. The new 
inspection method and the compliance times shall be approved by the 
Manager, Seattle ACO.

    Note 9: For the purposes of this AD, a design change is defined 
as any modification, alteration, or change to operating limitations.

    (f) Except as provided in paragraph (d)(2)(ii)(B) of this AD, 
cracked structure found during any inspection required by this AD 
shall be repaired, prior to further flight, in accordance with an 
FAA-approved method.
    (g) For airplanes on which the structure identified in Revision 
D is affected by any design change (including STC's) or repair that 
is accomplished after the effective date of this AD: Within 12 
months after that modification, alteration, or repair, assess the 
damage tolerance characteristics of each SSI created or affected by 
each repair or design change to determine the effectiveness of the 
applicable SSID inspection for each SSI and, if not effective, 
revise the FAA-approved maintenance or inspection program to include 
an inspection method and compliance times for each new or affected 
SSI, and to include the compliance times for initial and repetitive 
accomplishment of each inspection. The new inspection method and the 
compliance times shall be approved by the Manager, Seattle ACO.

    Note 10: Notwithstanding the provisions of paragraphs 5.1.17 and 
5.1.18 of the General Instructions of Revision D, which would permit 
deletions of modified, altered, or repaired structure from the SIP, 
the inspection of SSI's that are modified, altered, or repaired 
shall be done in accordance with a method approved by the Manager, 
Seattle ACO.

    (h) Before any airplane that is subject to this AD and that has 
exceeded the applicable compliance times specified in paragraph (c) 
of this AD can be added to an air carrier's operations 
specifications, a program for the accomplishment of the inspections 
required by this AD must be established in accordance with paragraph 
(h)(1) or (h)(2) of this AD, as applicable.
    (1) For airplanes that have been inspected in accordance with 
this AD, the inspection of each SSI must be accomplished by the new 
operator in accordance with the previous operator's schedule and 
inspection method, or the new operator's schedule and inspection 
method, whichever would result in the earlier accomplishment date 
for that SSI inspection. The compliance time for accomplishment of 
this inspection must be measured from the last inspection 
accomplished by the previous operator. After each inspection has 
been performed once, each subsequent inspection must be

[[Page 989]]

performed in accordance with the new operator's schedule and 
inspection method.
    (2) For airplanes that have not been inspected in accordance 
with this AD, the inspection of each SSI required by this AD must be 
accomplished either prior to adding the airplane to the air 
carrier's operations specification, or in accordance with a schedule 
and an inspection method approved by the Manager, Seattle ACO. After 
each inspection has been performed once, each subsequent inspection 
must be performed in accordance with the new operator's schedule.
    (i)(1) 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 11: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (2) Alternative methods of compliance, approved previously in 
accordance with AD 91-14-20, amendment 39-7061, are not considered 
to be approved as alternative methods of compliance with this AD.
    (j) 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.
    (k) The actions specified in paragraphs (b) and (c) shall be 
done in accordance with Boeing Document No. D6-37089, ``Supplemental 
Structural Inspection Document'' (SSID), Revision D, dated June 
1995, which contains the following list of effective pages:

------------------------------------------------------------------------
         Page number shown on page          Revision level shown on page
------------------------------------------------------------------------
List of Effective Pages...................  D
  Pages 1 thru 10
------------------------------------------------------------------------

    (Note: The issue date of Revision D is indicated only on the 
title page; no other page of the document is dated.). This 
incorporation by reference was approved previously by the Director 
of the Federal Register, in accordance with 5 U.S.C. 552(a) and 1 
CFR part 51, as of June 23, 1998 (63 FR 27465, May 19, 1998). 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 FAA, the FAA, Transport Airplane Directorate, 
Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC.
    (l) The effective date of this amendment remains June 23, 1998.

    Issued in Renton, Washington, on December 30, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-184 Filed 1-6-99; 8:45 am]
BILLING CODE 4910-13-U