[Federal Register Volume 60, Number 25 (Tuesday, February 7, 1995)]
[Proposed Rules]
[Pages 7143-7146]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-2932]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-NM-14-AD]
Airworthiness Directives; Boeing Model 707 and 720 Series
Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Supplemental notice of proposed rulemaking; reopening of
comment period.
-----------------------------------------------------------------------
SUMMARY: This document revises an earlier proposed airworthiness
directive (AD), applicable to certain Boeing Model 707 and 720 series
airplanes, that would have superseded an existing AD to require
repetitive inspections to detect cracks in certain areas of the upper
forward skin panels of the wing center section, and repair, if
necessary. That AD also would have provided an optional terminating
modification for the repetitive inspections. That proposal was prompted
by reports that the inspections required by the existing AD are not
effective in detecting fatigue cracks in a timely manner. This action
revises the proposed rule by reducing certain compliance times and by
revising the applicability statement of the AD. The actions specified
by this proposed AD are intended to prevent fatigue cracking and
subsequent failure of the upper forward skin panels of the wing center
section.
DATES: Comments must be received by March 6, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 94-NM-14-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, [[Page 7144]] 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: Phil Forde, Aerospace Engineer,
Airframe Branch, ANM-121S, 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:
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 must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 94-NM-14-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-103, Attention: Rules
Docket No. 94-NM-14-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
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
notice of proposed rulemaking (NPRM) in the Federal Register on July
18, 1994 (59 FR 36376). That NPRM would have superseded an existing AD
to require repetitive inspections to detect cracks in certain areas of
the upper forward skin panels of the wing center section, and repair,
if necessary. That AD also would have provided an optional terminating
modification for the repetitive inspections. That NPRM was prompted by
reports that the inspections required by the existing AD are not
effective in detecting fatigue cracks in a timely manner. That
condition, if not corrected, could result in failure of the upper
forward skin panels of the wing center section.
One commenter to the NPRM submitted a request that the proposal be
revised to eliminate duplicate or conflicting requirements with AD 85-
12-01 (50 FR 26690, June 28, 1985) for unmodified airplanes (those
having no bulb angle or thicker skin). That AD requires accomplishment
of inspections specified in Supplemental Structural Inspection Document
(SSID) D6-44860 for Model 707/720 series airplanes. The FAA concurs
partially. The SSID provides procedures for accomplishment of dye
penetrant or eddy current inspections to detect cracks on the upper
forward skin panels of the wing center section. However, the FAA has
determined that the dye penetrant inspection techniques contained in
the SSID for the affected airplanes have not been effective in
detecting cracks in a timely manner. Boeing has advised the FAA that it
plans to remove those inspections from the next revision of the SSID;
subsequently, the FAA may consider further rulemaking to revise AD 85-
12-01 accordingly. For this reason, the FAA finds that inspections
using eddy current techniques, as proposed in this supplemental NPRM,
are necessary to detect cracks effectively in a timely manner for those
airplanes having no bulb angle or thicker skin.
Further, upon reevaluation of certain inspection thresholds and
repetitive intervals, the FAA finds that the compliance times specified
in paragraphs (a), (a)(2)(i), and (b) of the proposal are less
conservative than those recommended in the SSID. In light of this
consideration, the FAA finds that, for unmodified airplanes, the
compliance times specified in this proposal must be revised to make
them more consistent with the more conservative times recommended in
the SSID. Therefore, the proposed repetitive interval of 1,000 landings
or 18 months, whichever occurs first, specified in paragraphs (a) and
(b) of the original NPRM, has been revised to 450 landings in this
supplemental NPRM. In addition, the proposed inspection threshold of
7,000 total landings, specified in paragraph (a)(2)(i) of the original
NPRM, has been revised to 6,400 total landings in this supplemental
NPRM. The FAA has determined that accomplishment of the required
actions at these revised compliance times will provide an acceptable
level of safety.
The commenter also submitted a request that the applicability
statement of the proposal be revised to specify airplanes listed in
Boeing Service Bulletin 2590, Revision 11, dated December 12, 1991.
Certain Model 707 series airplanes were modified during production and,
therefore, need not be inspected in accordance with the requirements of
the proposed AD; the service bulletin listing excludes those airplanes.
The FAA concurs, and has revised the proposal accordingly.
The FAA also has revised the proposed repetitive inspection
interval, specified in paragraph (c) of the original NPRM, to remove
the reference to an optional 18-month repetitive inspection interval
and to require that these inspections be performed only at intervals
not to exceed 1,000 landings. This revised interval corresponds with
the recommendation of the Structures Working Group for Model 707/720
series airplanes, and the FAA has determined that it will ensure that
cracking is detected in a timely manner.
Since these changes expand the scope of the originally proposed
rule, the FAA has determined that it is necessary to reopen the comment
period to provide additional opportunity for public comment.
As a result of recent communications with the Air Transport
Association (ATA) of America, the FAA has learned that, in general,
some operators may misunderstand the legal effect of AD's on airplanes
that are identified in the applicability provision of the AD, but that
have been altered or repaired in the area addressed by the AD. The FAA
points out that all airplanes identified in the applicability provision
of an AD are legally subject to the AD. If an airplane has been altered
or repaired in the affected area in such a way as to affect compliance
with the AD, the owner or operator is required to obtain FAA approval
for an alternative method of compliance with the AD, in accordance with
the paragraph of each AD that provides for such approvals. A note has
been included in this notice to clarify this requirement.
The FAA has recently reviewed the figures it has used over the past
several years in calculating the economic [[Page 7145]] impact of AD
activity. In order to account for various inflationary costs in the
airline industry, the FAA has determined that it is necessary to
increase the labor rate used in these calculations from $55 per work
hour to $60 per work hour. The economic impact information, below, has
been revised to reflect this increase in the specified hourly labor
rate.
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 would be affected by this proposed AD, that
it would take approximately 32 work hours per airplane to accomplish
the proposed actions, and that the average labor rate is $60 per work
hour. Based on these figures, the total cost impact of the proposed AD
on U.S. operators is estimated to be $157,440, or $1,920 per airplane.
The total 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.
Should an operator elect to accomplish the optional terminating
action that would be provided by this AD action, it would take
approximately 1,250 work hours to accomplish it, at an average labor
rate of $60 per work hour. The cost of required parts would be
approximately $45,000 per airplane. Based on these figures, the total
cost impact of the optional terminating action would be $120,000 per
airplane.
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. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing amendment 39-2056, and by
adding the following new airworthiness directive:
Boeing: 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 (f) 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.
(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 Master Inspection 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 master inspection service bulletins
as additional sources of service information concerning
accomplishment of the inspections required by paragraph (c) of this
AD.
[[Page 7146]] (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 in Boeing Master Inspection 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 in Boeing Master Inspection 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 in
Boeing Master Inspection 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) Accomplishment of the ``Reinforcing Stiffener Installation
and Skin Panel Replacement'' in accordance with Part III of the
Accomplishment Instructions of Boeing Service Bulletin 2590,
Revision 6, dated July 8, 1968; 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.
(f) 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.
(g) 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.
Issued in Renton, Washington, on February 1, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-2932 Filed 2-6-95; 8:45 am]
BILLING CODE 4910-13-U
