[Federal Register Volume 66, Number 78 (Monday, April 23, 2001)]
[Rules and Regulations]
[Pages 20383-20386]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-9663]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-42-AD; Amendment 39-12179; AD 2001-08-02]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 707 and 720 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes two existing airworthiness 
directives (AD), applicable to all Boeing Model 707 and 720 series 
airplanes, that currently require inspections of the upper chords of 
the wing front and rear spars, repair, if necessary, and application of 
corrosion inhibitor to the inspected areas. This amendment requires 
repetitive inspections of the upper and lower chords on the wing front 
and rear spars, repair, if necessary, and application of corrosion 
inhibitor to the inspected areas. These actions are necessary to find 
and fix stress corrosion cracking of the upper and lower chords on the 
wing front and rear spars, which could result in reduced structural 
integrity of the wing. This action is intended to address the 
identified unsafe condition.

DATES: Effective May 8, 2001.
    The incorporation by reference of certain publications, as listed 
in the regulations, is approved by the Director of the Federal Register 
as of May 8, 2001.
    The incorporation by reference of Boeing Service Bulletin 3240, 
Revision 3, dated October 18, 1985, as listed in the regulations, was 
approved previously by the Director of the Federal Register as of March 
10, 1992 (57 FR 4153, February 4, 1992).
    Comments for inclusion in the Rules Docket must be received on or 
before June 22, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-42-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. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the

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Internet using the following address: [email protected]. 
Comments sent via fax or the Internet must contain ``Docket No. 2001-
NM-42-AD'' in the subject line and need not be submitted in triplicate. 
Comments sent via the Internet as attached electronic files must be 
formatted in Microsoft Word 97 for Windows or ASCII text.
    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: Duong Tran, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2773; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: On May 28, 1986, the FAA issued AD 86-11-06, 
amendment 39-5327 (51 FR 20249, June 4, 1986), applicable to certain 
Boeing Model 707 and 720 series airplanes, to require repetitive 
inspections to detect cracks or corrosion of the upper chord of the 
wing front spar, repair, if necessary, and application of corrosion 
inhibitor. The actions required by that AD are intended to ensure 
continued structural integrity of the upper chord of the wing front 
spar.
    On January 17, 1992, the FAA issued AD 92-03-12, amendment 39-8169 
(57 FR 4153, February 4, 1992), applicable to certain Boeing Model 707 
and 720 series airplanes, to require repetitive inspections to detect 
cracks or corrosion of the upper chord of the wing rear spar, repair, 
if necessary, and application of corrosion inhibitor. The actions 
required by that AD are intended to ensure continued structural 
integrity of the upper chord of the wing rear spar.

Actions Since Issuance of Previous Rule

    Since the issuance of those AD's, a 31-inch crack was found in the 
radius of the lower chord of the wing front spar in the dry bay area 
between wing stations 360 and 400. Investigation revealed that 19 
inches of the crack were due to stress corrosion, while the remainder 
was due to ductile separation. While the existing AD's require 
repetitive inspections to detect cracks or corrosion of the upper chord 
of the wing front and rear spars, engineering evaluation suggests that 
both upper and lower chords on the front and rear spars may be subject 
to such cracking. Cracking of an upper or lower chord of the wing front 
or rear spar, if not found, could result in reduced structural 
integrity of the wing.

Explanation of Relevant Service Information

    AD 86-11-06 requires inspections of the upper chord of the wing 
front spar per Boeing Service Bulletin 3240, Revision 1, dated November 
13, 1981, Revision 2, dated May 3, 1985, or Revision 3, dated October 
18, 1985. AD 92-03-12 requires inspections of the upper chord of the 
wing rear spar per Boeing Service Bulletin 3240, Revision 3. Since the 
issuance of those AD's, Boeing has issued All Base Message (ABM) M-
7200-01-00062, dated January 5, 2001. The ABM modifies the procedures 
described in Boeing Service Bulletin 3240, Revision 3, to emphasize 
certain procedures for solvent cleaning, detailed visual inspections 
(referred to in the service bulletin and the ABM as ``close visual 
inspections'') to detect corrosion or cracking of the upper and lower 
chords on the wing front and rear spars, application of surface finish, 
and application of corrosion inhibitor. The ABM also recommends a new 
compliance time for accomplishment of the next inspection. Performing 
inspections and follow-on actions per Revision 3 of the service 
bulletin as revised by the ABM eliminates the need for the inspections 
required by the existing AD's.

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 86-11-06 and AD 92-03-12 to continue to require the 
inspections and follow-on actions required by those AD's. This AD also 
requires accomplishment of the actions specified in the service 
bulletin as modified by the procedures in the ABM described previously, 
except as discussed below. Once the new requirements of this AD have 
been done, the inspections per the old AD's are no longer required.

Differences Between Service Information and This AD

    This AD differs from the service information in these ways:
     If any crack or corrosion is found, this AD requires 
repair of such damage before further flight. However, the service 
bulletin specifies that stop drilling of cracks allows the repair to be 
deferred. The FAA finds that stop drilling is not adequate to arrest 
stress corrosion cracking; thus, stop drilling is not adequate to 
ensure the safety of the affected airplane fleet. Thus, this AD 
requires that any cracking or corrosion that is found be repaired 
before further flight.
     Also, although the service bulletin specifies that the 
manufacturer may be contacted for disposition of certain repair 
conditions, this AD requires the repair of those conditions to be done 
per a method approved by the FAA, or per data meeting the type 
certification basis of the airplane approved by a Boeing Company 
Designated Engineering Representative who has been authorized by the 
Manager, Seattle ACO, to make such findings.

Explanation of Changes in Restatement of Requirements of Existing 
AD's

    Paragraphs (a) through (i) restate the requirements of AD 86-11-06 
and AD 92-03-12. Certain existing requirements specify ``close visual 
inspections.'' The FAA finds that ``detailed visual inspection'' is a 
more accurate term for the type of inspections that are required. 
Therefore, the FAA has revised the existing requirements as stated in 
paragraphs (a) and (f) of this AD to identify the required inspections 
as ``detailed visual inspections.'' Also, Note 2 has been added to 
include a definition of ``detailed visual inspection.''
    Additionally, the restatement of requirements of the existing AD's 
has been revised to remove all references to the use of ``later FAA-
approved revisions'' of Boeing Service Bulletin 3240, Revision 1, in 
order to be consistent with FAA policy in that regard. Instead, the FAA 
has listed the specific revisions of the service bulletin that have 
been approved. The FAA has determined that this change will not 
increase the economic burden on any operator, nor will it increase the 
scope of the AD.

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

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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.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the AD is 
being requested.
     Include justification (e.g., reasons or data) for each 
request.
    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 2001-NM-42-AD.'' The postcard will be date-stamped and 
returned to the commenter.

Regulatory Impact

    The regulations adopted herein will not have a substantial direct 
effect 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, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendments 39-5327 (51 FR 
20249, June 4, 1986) and 39-8169 (57 FR 4153, February 4, 1992), and by 
adding a new airworthiness directive (AD), amendment 39-12179, to read 
as follows:

2001-08-02  Boeing: Amendment 39-12179. Docket 2001-NM-42-AD. 
Supersedes AD 86-11-06, Amendment 39-5327, and AD 92-03-12, 
Amendment 39-8169.

    Applicability: All Model 707 and 720 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 (m) 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.


    Note 2:
    For the purposes of this AD, a detailed visual inspection is 
defined as: ``An intensive visual examination of a specific 
structural area, system, installation, or assembly to detect damage, 
failure, or irregularity. Available lighting is normally 
supplemented with a direct source of good lighting at intensity 
deemed appropriate by the inspector. Inspection aids such as mirror, 
magnifying lenses, etc., may be used. Surface cleaning and elaborate 
access procedures may be required.''

    Compliance: Required as indicated, unless accomplished 
previously.
    To find and fix stress corrosion cracking of the upper and lower 
spar chords on the front and rear spars of the wing, which could 
result in reduced structural integrity of the wing, accomplish the 
following:

Restatement of Requirements of AD 86-11-06

AD 86-11-06: Repetitive Inspections

    (a) For Model 707 and 720 series airplanes with 15,000 or more 
landings: Within 100 landings or 60 days after July 14, 1986 (the 
effective date of AD 86-11-06, amendment 39-5327), unless previously 
accomplished within the last 900 landings or 305 days prior to July 
14, 1986, perform a detailed visual inspection of the wing front 
spar upper chord for cracks and corrosion, in accordance with Boeing 
Service Bulletin 3240, Revision 1, dated November 13, 1981, Revision 
2, dated May 3, 1985, or Revision 3, dated October 18, 1985. Repeat 
the inspection thereafter at intervals not to exceed 1,000 landings 
or one year, whichever occurs first.

AD 86-11-06: Repair

    (b) If cracks or corrosion are found during the inspection per 
paragraph (a) of this AD, repair prior to further flight in 
accordance with Boeing Service Bulletin 3240, Revision 3, dated 
October 18, 1985.

AD 86-11-06: Stop Drilling, Repetitive Inspections, and Permanent 
Repair

    (c) For airplanes subject to paragraph (a) of this AD: Cracks 
which have been repaired in accordance with the ``stop drilling'' 
procedure described in Part III, Figure 2, of Boeing Service 
Bulletin 3240, Revision 1, dated November 13, 1981, Revision 2, 
dated May 3, 1985, or Revision 3, dated October 18, 1985, must be 
visually inspected at intervals not to exceed 300 landings, until 
permanently repaired in accordance with Part III, Figure 2, of 
Service Bulletin 3240, Revision 3, dated October 18, 1985. A 
permanent repair must be completed within 1,000 landings or one 
year, whichever occurs first after July 14, 1986.

AD 86-11-06: Repair Per Earlier Service Bulletins

    (d) For airplanes subject to paragraph (a) of this AD: Cracks 
greater than 2.0 inches in length, which have been previously 
repaired in accordance with Boeing Service Bulletin 3240, Revision 
1, dated November 13, 1981, or Revision 2, dated May 3, 1985, must 
be repaired in accordance with Revision 3, dated October 18, 1985, 
within 1,000 landings or one year, whichever occurs first after July 
14, 1986.

AD 86-11-06: Application of Corrosion Inhibitor

    (e) For airplanes subject to paragraph (a) of this AD: After 
each of the above inspections and repairs have been performed, apply 
BMS-3-23 corrosion inhibitor, or equivalent, to the affected areas.

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Restatement of Requirements of AD 92-03-12

AD 92-03-12: Repetitive Inspections

    (f) For all Model 707 and 720 series airplanes: Perform a 
detailed visual inspection for cracks and corrosion of the wing rear 
spar upper chord from wing station (WS) 109.45 to WS 360 for Model 
707-300 series airplanes; or from WS 180.71 to WS 360 for Model 720, 
707-100, and 707-200 series airplanes; at rib and stiffener 
locations. Inspect in accordance with Boeing Service Bulletin 3240, 
Revision 3, dated October 18, 1985, prior to the later of the times 
specified in subparagraphs (f)(1) and (f)(2) of this AD, unless 
previously accomplished within the last 900 flight cycles or 335 
days prior to June 19, 1991 (the effective date of AD 91-11-06). 
Repeat the inspection at intervals not to exceed 1,000 flight cycles 
or one year, whichever occurs first.
    (1) Within the next 30 days or 100 flight cycles after June 19, 
1991; or
    (2) Prior to the accumulation of 10,000 total flight cycles.

AD 92-03-12: Corrective Actions

    (g) If cracks or corrosion areas are found during any inspection 
per paragraph (f) of this AD, prior to further flight, accomplish 
either subparagraph (g)(1) or (g)(2) of this AD:
    (1) Repair, other than by stop drill procedure, in accordance 
with Part III, Figure 2, of Boeing Service Bulletin 3240, Revision 
3, dated October 18, 1985 (this is considered the ``final repair''), 
or
    (2) Repair in accordance with the stop drill procedures 
specified in Part III, Figure 2, of Boeing Service Bulletin 3240, 
Revision 3, dated October 18, 1985. This repair method may only be 
used provided that the limitations specified in Part III, Figure 2, 
Items 5a and 5b, of the service bulletin are met.
    (i) Immediately after stop drilling, conduct an eddy current 
inspection of the stop drill hole in accordance with the 
instructions in Section 5-5-1 of Boeing Document D6-7170, 
Nondestructive Test Document, to ensure that the crack does not 
extend beyond the stop drill. Thereafter, inspect visually for crack 
growth beyond the stop drill at intervals not exceeding 300 flight 
cycles.
    (ii) If crack growth beyond the stop drill occurs, prior to 
further flight, accomplish the final repair in accordance with 
paragraph (g)(1) of this AD.
    (iii) Within 1,000 flight cycles or one year, whichever occurs 
first, after the stop drill has been accomplished, accomplish the 
final repair in accordance with paragraph (g)(1) of this AD.

AD 92-03-12: Inspection of Previously Stop Drilled Cracks

    (h) If previously stop drilled cracks are found during any 
inspection required by paragraph (f) of this AD, conduct an eddy 
current inspection of the stop drill hole for crack growth beyond 
the stop drill, in accordance with the instructions in Section 5-5-1 
of Boeing Document D6-7170, Nondestructive Test Document.
    (1) If growth beyond the stop drill has occurred, prior to 
further flight, repair in accordance with paragraph (g)(1) of this 
AD.
    (2) If growth beyond the stop drill has not occurred, and the 
limitations specified in Part III, Figure 2, Items 5a and 5b, of 
Boeing Service Bulletin 3240, Revision 3, dated October 18, 1985, 
are met, prior to further flight accomplish either subparagraph 
(h)(1)(i) or (h)(1)(ii) of this AD:
    (i) Repair in accordance with paragraph (g)(1) of this AD; or
    (ii) Reinspect visually for crack growth beyond the stop drill 
at intervals not exceeding 300 flight cycles.
    (A) If crack growth beyond the stop drill occurs, prior to 
further flight, accomplish the final repair in accordance with 
paragraph (g)(1) of this AD.
    (B) Within 1,000 flight cycles or one year, whichever occurs 
first after the initial inspection revealed the stop drill crack, 
accomplish the final repair in accordance with paragraph (g)(1) of 
this AD.

AD 92-03-12: Application of Corrosion Inhibitor

    (i) After each of the inspections and repairs required by 
paragraphs (f) and (g) of this AD have been performed, apply BMS 3-
23 corrosion inhibitor, or equivalent, to the affected areas.

New Requirements of this AD

New Repetitive Detailed Visual Inspections

    (j) Within 30 days after the effective date of this AD, do a 
detailed visual inspection for corrosion or cracking of the upper 
and lower chords on the front and rear spars, per Boeing Service 
Bulletin 3240, Revision 3, dated October 18, 1985, as modified by 
Boeing All Base Message (ABM) M-7200-01-00062, dated January 5, 
2001. Repeat the inspections thereafter at least every 6 months or 
1,000 flight cycles, whichever comes first. Doing the initial 
inspection per this paragraph terminates the inspections required by 
paragraphs (a) and (f) of this AD.

    Note 3: There is no terminating action available for the 
repetitive inspections required by paragraph (j) of this AD.

Repair

    (k) If any cracking or corrosion is found during any inspection 
per paragraph (j) of this AD: Before further flight, repair per 
Boeing Service Bulletin 3240, Revision 3, dated October 18, 1985, as 
modified by Boeing ABM M-7200-01-00062, dated January 5, 2001, 
except, where the service information specifies to contact Boeing 
for repair instructions, before further flight, repair per a method 
approved by the Manager, Seattle Aircraft Certification Office 
(ACO), FAA; or per data meeting the type certification basis of the 
airplane approved by a Boeing Company Designated Engineering 
Representative who has been authorized by the Manager, Seattle ACO, 
to make such findings. For a repair method to be approved by the 
Manager, Seattle ACO, as required by this paragraph, the approval 
letter must specifically reference this AD.

    Note 4: ``Stop drilling'' of cracks as a means to defer repair, 
as specified in Boeing Service Bulletin 3240, Revision 3, dated 
October 18, 1985, is Not allowed by paragraph (k) of this AD.

Application of Corrosion Inhibitor

    (l) After each inspection required by paragraph (j) of this AD 
and any repair per paragraph (k) of this AD, before further flight, 
apply BMS 3-23 corrosion inhibitor to the affected areas.

Alternative Methods of Compliance

    (m) 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 5: 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

    (n) 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.

Incorporation by Reference

    (o) Except as provided by paragraph (e), (g)(2)(ii), (h), (i), 
(k), and (l) of this AD; the actions shall be done in accordance 
with Boeing Service Bulletin 3240, Revision 1, dated November 13, 
1981; Boeing Service Bulletin 3240, Revision 2, dated May 3, 1985; 
Boeing Service Bulletin 3240, Revision 3, dated October 18, 1985; or 
Boeing All Base Message M-7200-01-00062, dated January 5, 2001; as 
applicable.
    (1) The incorporation by reference of Boeing Service Bulletin 
3240, Revision 1, dated November 13, 1981; Boeing Service Bulletin 
3240, Revision 2, dated May 3, 1985; and Boeing All Base Message M-
7200-01-00062, dated January 5, 2001, 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 Service Bulletin 
3240, Revision 3, dated October 18, 1985, was approved previously by 
the Director of the Federal Register as of March 10, 1992 (57 FR 
4153, February 4, 1992).
    (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.

Effective Date

    (p) This amendment becomes effective on May 8, 2001.

    Issued in Renton, Washington, on April 11, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-9663 Filed 4-20-01; 8:45 am]
BILLING CODE 4910-13-U