[Federal Register Volume 60, Number 156 (Monday, August 14, 1995)]
[Rules and Regulations]
[Pages 41795-41798]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-19120]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-14-AD; Amendment 39-9330; AD 95-17-01]


Airworthiness Directives; Boeing Model 707 and 720 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to certain Boeing Model 707 and 720 series airplanes, 
that currently requires repetitive visual and dye penetrant inspections 
to detect cracks in areas of the upper forward skin panels of the wing 
center section, and repair, if necessary. It also provides an optional 
terminating modification for the repetitive inspections. This amendment 
requires repetitive visual and eddy current inspections to detect 
cracks in areas of the upper forward skin panels of the wing center 
section, and repair, if necessary. This amendment is prompted by 
reports indicating that the inspections required by the existing AD are 
not effective in detecting fatigue cracks in a timely manner. The 
actions specified by this AD are intended to prevent fatigue cracking 
and subsequent failure of the upper forward skin panels of the wing 
center section.

DATES: Effective on September 13, 1995.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 13, 1995.

ADDRESSES: 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 Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 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: Phil Forde, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington, 98055-4056; telephone (206) 227-2771; fax (206) 227-1181.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to add an airworthiness directive 
(AD), applicable to certain Boeing Model 707 and 720 series airplanes, 
was published as a supplemental notice of proposed rulemaking (NPRM) in 
the Federal Register on February 7, 1995 (60 FR 7143). That 
supplemental NPRM proposed to supersede AD 68-18-03, amendment 39-2056. 
That AD currently requires repetitive visual and dye penetrant 
inspections to detect cracks on the upper forward skin panels of the 
wing center section, and repair, if necessary. It also provides an 
optional terminating modification for the repetitive inspections. The 
supplemental NPRM proposed to require repetitive visual and eddy 
current inspections to detect cracks on the upper forward skin panels 
of the wing center section, and repair, if necessary.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the single comment received.
    The commenter requests that paragraph (e) of the proposal be 
revised to allow that the terminating action specified in that 
paragraph be accomplished in accordance with procedures contained in 
revisions prior to Revision 6 of Boeing Service Bulletin 2590, provided 
that, in addition to the installation of reinforcing stiffeners, the 
forward skin panel is replaced. The commenter indicates that the 
modifications described in these earlier revisions of the service 
bulletin are identical to those specified in Revisions 6 and 
subsequent. The commenter adds that the ``aging fleet document'' 
(Boeing Document D6-54496), which addresses the affected airplanes, 
specifies that modifications accomplished in accordance with the 
original issue through Revision 8 of Boeing Service Bulletin 2590 are 
considered to be terminating action, provided that new forward skin 
panels are installed. The commenter states that the inconsistency
 
[[Page 41796]]

between the proposal and the ``aging fleet document'' in this regard 
has caused confusion among some operators as to whether airplanes 
modified in accordance with earlier revisions of the service bulletin 
are considered to be in compliance with the proposed AD.
    The FAA concurs partially. The FAA has re-examined the earlier 
revisions of the service bulletin, and has determined that the original 
issue and Revisions 1 through 3 of the service bulletin were issued as 
telegraphic documents. These revisions do not adequately address 
procedures for accomplishing the terminating modifications in 
sufficient detail. Therefore, the FAA does not consider these revisions 
to be acceptable for accomplishment of the terminating modification 
specified in this AD. However, Revision 4 does provide adequate 
procedures for accomplishing the terminating modification for Model 720 
series airplanes, provided that the forward skin panel also is replaced 
in accordance with the service bulletin. In addition, Revision 5 
contains adequate information for accomplishment of the terminating 
modification for both Model 707 and 720 series airplanes, provided that 
the forward skin panel also is replaced in accordance with the service 
bulletin. These determinations have been specified in paragraphs (e) 
and (f) of the final rule for Models 707 and 720 series airplanes, 
respectively.
    Certain service bulletin titles were referenced incorrectly in NOTE 
2 and paragraphs (c)(1), (c)(2), and (c)(3) of the supplemental NPRM as 
``Boeing Master Inspection Service Bulletins.'' The appropriate titles 
for these service documents are ``Boeing Service Bulletins.'' The FAA 
has revised the note and those paragraphs of the final rule 
accordingly. In addition, the FAA has added references to specific page 
numbers of those service bulletins for the convenience of operators.
    In addition, paragraph (e) of the supplemental NPRM did not specify 
that Revision 6 of Boeing Service Bulletin 2590 was issued as an alert 
service bulletin. The final rule has been revised accordingly.
    After careful review of the available data, including the comment 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.
    -There are approximately 416 Model 707 and 720 series airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 82 
airplanes of U.S. registry will be affected by this AD, that it will 
take approximately 32 work hours per airplane to accomplish the 
required actions, and that the average labor rate is $60 per work hour. 
Based on these figures, the total cost impact of the AD on U.S. 
operators is estimated to be $157,440, or $1,920 per airplane, per 
inspection cycle. -
    The total cost impact figure discussed above is based on 
assumptions that no operator has yet accomplished any of the 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted. -
    Should an operator elect to accomplish the optional terminating 
action that is provided by this AD action, it will take approximately 
1,250 work hours to accomplish it, at an average labor rate of $60 per 
work hour. The cost of required parts is approximately $45,000 per 
airplane. Based on these figures, the total cost impact of the optional 
terminating action is estimated to be $120,000 per airplane. -
    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. -
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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), 40101, 40113, 44701.


Sec. 39.13  [Amended] -

    2. Section 39.13 is amended by removing amendment 39-2056, and by 
adding a new airworthiness directive (AD), amendment 39- , to read as 
follows:

95-17-01  Boeing: Amendment 39-9330. Docket 94-NM-14-AD. Supersedes 
AD 68-18-03, Amendment 39-2056.

    -Applicability: Model 707 and 720 series airplanes; as listed in 
Boeing Service Bulletin 2590, Revision 11, dated December 12, 1991; 
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 use the authority 
provided in paragraph (g) of this AD to request approval from the 
FAA. This approval may address either no action, if the current 
configuration eliminates the unsafe condition; or different actions 
necessary to address the unsafe condition described in this AD. Such 
a request should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

    -Compliance: Required as indicated, unless accomplished 
previously. -
    To prevent fatigue cracking and subsequent failure of the upper 
forward skin panels of the wing center section, accomplish the 
following: -
    (a) For Model 707-100, -200, -300, -300B, -300C, and -400 series 
airplanes on which no bulb angle stiffeners have been installed in 
accordance with Boeing Service Bulletin 2590: Perform a visual 
inspection and an eddy current inspection to detect cracks in the 
areas of the upper forward skin of the wing center section specified 
in paragraphs b. and f.(1) of Part I of the Accomplishment 
Instructions of Boeing Service Bulletin 2590, Revision 8, dated June 
2, 1972; Revision 9, dated March 14, 1975; Revision 10, dated 
January 31, 1991; or Revision 11, dated December 12, 1991. Perform 
the inspections at the time specified in paragraph (a)(1) or (a)(2) 
of this AD, as applicable, in accordance with the procedures 
specified in the service bulletin. Repeat these inspections 
thereafter at intervals not to exceed 450 landings.
    -(1) For Model 707-300, -300B, -300C, and -400 series airplanes: 
Inspect at the later of the times specified in paragraphs (a)(1)(i) 
and (a)(1)(ii) of this AD. -

[[Page 41797]]

    (i) Prior to the accumulation of 6,000 total landings; or
    (ii) Within 500 landings or 18 months after the effective date 
of this AD, whichever occurs first.
    (2) For Model 707-100 and -200 series airplanes: 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 6,400 total landings; or
    (ii) Within 500 landings or 18 months after the effective date 
of this AD, whichever occurs first.-
    (b) For Model 720 and 720B series airplanes on which no bulb 
angle stiffeners have been installed in accordance with Boeing 
Service Bulletin 2590: Perform a visual inspection and an eddy 
current inspection to detect cracks in the area of the upper forward 
skin of the wing center section specified in paragraph b. of Part I 
of the Accomplishment Instructions of Boeing Service Bulletin 2590, 
Revision 8, dated June 2, 1972; Revision 9, dated March 14, 1975; 
Revision 10, dated January 31, 1991; or Revision 11, dated December 
12, 1991. Perform the inspections at the later of the times 
specified in paragraphs (b)(1) and (b)(2) of this AD, in accordance 
with the procedures specified in the service bulletin. Repeat these 
inspections thereafter at intervals not to exceed 450 landings. -
    (1) Prior to the accumulation of 4,000 total landings; or -
    (2) Within 500 landings or 18 months after the effective date of 
this AD, whichever occurs first. -
    (c) For Model 720 and 720B, and 707-100, -200, -300, -300B, -
300C, and -400 series airplanes on which bulb angle stiffeners have 
been installed, but on which the wing skin has not been replaced, in 
accordance with Boeing Service Bulletin 2590: Accomplish the 
inspections required by paragraph (c)(1), (c)(2), or (c)(3) of this 
AD, as applicable, in accordance with Boeing Service Bulletin 2590, 
Revision 11, dated December 12, 1991. Repeat these inspections 
thereafter at intervals not to exceed 1,000 landings.

    -Note 2: Revision 11 of Boeing Service Bulletin 2590 is part of 
Boeing Service Bulletins 3484 (for Model 707-100 and -200 series 
airplanes), 3485 (for Model 720 and 720B series airplanes), and 3486 
(for Model 707-300, -300B, -300C, and -400 series airplanes), all 
dated December 12, 1991. Boeing Service Bulletin 2590 references 
these service bulletins as additional sources of service information 
concerning accomplishment of the inspections required by paragraph 
(c) of this AD.

    -(1) For Model 720 and 720B series airplanes: Perform a visual 
and an eddy current inspection to detect cracks in the areas of the 
upper forward skin of the wing center section specified on pages 34 
and 35 of Boeing Service Bulletin 3485, dated December 12, 1991, at 
the later of the times specified in paragraphs (c)(1)(i) and 
(c)(1)(ii) of this AD. -
    (i) Prior to the accumulation of 2,200 landings after 
installation of the bulb angle stiffeners; or -
    (ii) Within 500 landings or 18 months after the effective date 
of this AD, whichever occurs first. -
    (2) For Model 707-300, -300B, -300C, and -400 series airplanes: 
Perform a visual and an eddy current inspection to detect cracks in 
the areas of the upper forward skin of the wing center section 
specified on page 55 of Boeing Service Bulletin 3486, dated December 
12, 1991, at the later of the times specified in paragraphs 
(c)(2)(i) and (c)(2)(ii) of this AD. -
    (i) Prior to the accumulation of 2,200 landings after 
installation of the bulb angle stiffeners; or
    (ii) Within 500 landings or 18 months after the effective date 
of this AD, whichever occurs first.
    (3) For Model 707-100 and -200 series airplanes: Perform a 
visual and an eddy current inspection to detect cracks in the areas 
of the upper forward skin of the wing center section specified on 
pages 37 and 38 of Boeing Service Bulletin 3484, dated December 12, 
1991, at the later of the times specified in paragraphs (c)(3)(i) 
and (c)(3)(ii) of this AD.
    (i) Prior to the accumulation of 2,200 landings after 
installation of the bulb angle stiffeners; or
    (ii) Within 500 landings or 18 months after the effective date 
of this AD, whichever occurs first.
    (d) If any crack is found during any inspection required by 
paragraph (a), (b), or (c) of this AD, prior to further flight, 
repair in accordance with Part II of the Accomplishment Instructions 
of Boeing Service Bulletin 2590, Revision 7, dated September 22, 
1969; Revision 8, dated June 2, 1972; Revision 9, dated March 14, 
1975; Revision 10, dated January 31, 1991; or Revision 11, dated 
December 12, 1991.
    (e) For Model 707 series airplanes: Accomplishment of the 
``Reinforcing Stiffener Installation and Skin Panel Replacement'' in 
accordance with Part III of the Accomplishment Instructions of 
Boeing Alert Service Bulletin 2590, Revision 6, dated July 8, 1968; 
Boeing Service Bulletin 2590, Revision 7, dated September 22, 1969, 
Revision 8, dated June 2, 1972, Revision 9, dated March 14, 1975, 
Revision 10, dated January 31, 1991, or Revision 11, dated December 
12, 1991; constitutes terminating action for the inspections 
required by paragraphs (a), (b), and (c) of this AD. Accomplishment 
of the reinforcement and replacement in accordance with Boeing Alert 
Service Bulletin 2590, Revision 5, dated September 20, 1967, also is 
considered acceptable for compliance with paragraph (e) of this AD 
provided that the forward skin panel also is replaced in accordance 
with that service bulletin.
    (f) For Model 720 series airplanes: Accomplishment of the 
``Reinforcing Stiffener Installation and Skin Panel Replacement'' in 
accordance with Part III of the Accomplishment Instructions of 
Boeing Alert Service Bulletin 2590, Revision 6, dated July 8, 1968; 
Boeing Service Bulletin 2590, Revision 7, dated September 22, 1969, 
Revision 8, dated June 2, 1972, Revision 9, dated March 14, 1975, 
Revision 10, dated January 31, 1991, or Revision 11, dated December 
12, 1991; constitutes terminating action for the inspections 
required by paragraphs (a), (b), and (c) of this AD. Accomplishment 
of the reinforcement and replacement in accordance with Boeing Alert 
Service Bulletin 2590, Revision 4, dated May 26, 1967, or Revision 
5, dated September 20, 1967, also is considered acceptable for 
compliance with paragraph (f) of this AD provided that the forward 
skin panel also is replaced in accordance with that service 
bulletin.
    (g) 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (h) 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.
    (i) The actions shall be done in accordance with the following 
service documents:

Boeing Alert Service Bulletin 2590, Revision 4, dated May 26, 1967;
Boeing Alert Service Bulletin 2590, Revision 5, dated September 20, 
1967;
Boeing Alert Service Bulletin 2590, Revision 6, dated July 8, 1968;
Boeing Service Bulletin 2590, Revision 7, dated September 22, 1969;
Boeing Service Bulletin 2590, Revision 8, dated June 2, 1972;
Boeing Service Bulletin 2590, Revision 9, dated March 14, 1975;
Boeing Service Bulletin 2590, Revision 10, dated January 31, 1991;
Boeing Service Bulletin 2590, Revision 11, dated December 12, 1991;
Pages 37 and 38 of Boeing Service Bulletin 3484, dated December 12, 
1991;
Pages 34 and 35 of Boeing Service Bulletin 3485, dated December 12, 
1991; and
Pages 55 and 56 of Boeing Service Bulletin 3486, dated December 12, 
1991.

    Boeing Alert Service Bulletin 2590, Revision 6, dated July 8, 
1968, contains the following specified effective pages:

                                                                                                                

[[Page 41798]]
------------------------------------------------------------------------
                                    Revision                            
                                     level                              
             Page No.               shown on      Date shown on page    
                                      page                              
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1, 3-5, 7, 9, 10, 14, 16.........          6  July 8, 1968.             
2, 6, 8, 11-13, 15...............          5  September 20, 1967.       
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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.
    (j) This amendment becomes effective on September 13, 1995.

    Issued in Renton, Washington, on July 28, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-19120 Filed 8-11-95; 8:45 am]
BILLING CODE 4910-13-U