[Federal Register Volume 62, Number 18 (Tuesday, January 28, 1997)]
[Rules and Regulations]
[Pages 3985-3988]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-1437]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-NM-99-AD; Amendment 39-9893; AD 97-02-08]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Model DC-9, DC-9-80
and C-9 (Military) Series Airplanes, and Model MD-88 Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to certain McDonnell Douglas Model DC-9, DC-9-80 and C-9
(military) series airplanes, and Model MD-88 airplanes It requires
either the installation of external protective
[[Page 3986]]
doublers between the outboard flight spoiler actuators and the aft spar
webs of the wings, or replacement of the pistons of the outboard flight
spoiler actuators with improved pistons. This amendment is prompted by
reports of failure of the piston of the outboard flight spoiler
actuator due to fatigue at the clevis end of the upper lug mounting
hole of the piston. The actions specified by this AD are intended to
prevent such failure of the piston and the consequent puncturing of the
aft spar web, which could result in fuel leakage and reduced structural
integrity of the wings.
DATES: Effective March 4, 1997.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of March 4, 1997.
ADDRESSES: The service information referenced in this AD may be
obtained from McDonnell Douglas Corporation, 3855 Lakewood Boulevard,
Long Beach, California 90846, Attention: Technical Publications
Business Administration, Department C1-L51 (2-60). 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 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.
FOR FURTHER INFORMATION CONTACT: Brent Bandley, Aerospace Engineer,
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification
Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone
(310) 627-5237; fax (310) 627-5210.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an airworthiness
directive (AD) that is applicable to certain McDonnell Douglas Model
DC-9, DC-9-80 and C-9 (military) series airplanes, and Model MD-88
airplanes was published in the Federal Register on September 17, 1996
(61 FR 48864). That action proposed to require either installation of
external protective doublers between the aft spar webs and the pistons
of the outboard flight spoiler actuators on the wings, or replacement
of the pistons of the outboard flight spoiler actuators with improved
pistons.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
Support for the Proposal
Several commenters support the proposed rule.
Request to Permit Use of Previously Issued Service Documents
One commenter requests that the proposed rule be revised to give
credit to those operators who previously have accomplished either of
the proposed actions in accordance with earlier versions of McDonnell
Douglas Service Bulletin 27-300. This commenter, a U.S. operator,
points out that the proposal cites only Revision 2 of that service
bulletin as the appropriate source of service information. However, the
commenter has already accomplished the actions on its fleet in
accordance with the initial release of that service bulletin, which was
issued on April 14, 1992. The commenter wants assurance that it will
not have to repeat the actions in accordance with Revision 2 of the
service bulletin.
The FAA concurs that credit should be given as requested by this
commenter. The final rule has been revised to indicate that the use of
previous versions of the referenced service bulletin is acceptable for
compliance with this AD.
Request to Extend Compliance Time for Replacement of Pistons
One commenter requests that the compliance time for replacement of
the pistons of the outboard flight spoiler actuators, as specified in
proposed paragraph (a)(2), be extended from the proposed 5,000 landings
(after the effective date of the final rule) to 10,500 landings. The
commenter requests this extension so that the replacement can be
accomplished during a regularly scheduled heavy maintenance visit,
where trained personnel and ample parts would be available.
The FAA does not concur with the commenter's request. In developing
an appropriate compliance time for this action, the FAA considered not
only the degree of urgency associated with addressing the subject
unsafe condition, but the availability of necessary parts and the
practical aspect of accomplishing the replacement within an interval of
time that parallels normal scheduled maintenance for the majority of
affected operators. The FAA also took into account the manufacturers'
recommendation (specified in McDonnell Douglas Service Bulletin DC9-27-
300) that the replacement be conducted ``at the earliest practical
maintenance period.'' The FAA finds that, for the majority of affected
operators, some scheduled maintenance will occur within the 5,000-
landing compliance period; thus, special scheduling for the
accomplishment of the replacement can be avoided. No technical data has
been presented to the FAA to justify extending the compliance time any
further. In consideration of these factors, the FAA has determined that
the 5,000-landing compliance time for accomplishing the replacement of
pistons (or the installation of doublers) is both appropriate and
warranted.
Request to Allow Repetitive Inspections in Lieu of Replacement of
Pistons
One commenter requests that, in lieu of the proposed installation
or replacement actions, the proposed rule be revised to allow operators
to conduct repetitive non-destructive test (NDT) inspections of the
pistons and actuator assembly at intervals of 3,000 flight hours or
3,000 flight cycles. The commenter states that most of the subject
actuators already are being ``driven off'' these airplanes by the
requirements of AD 90-18-03 [amendment 39-6701, (50 FR 34704, August
24, 1990)], which mandated the inspections and modifications specified
in ``DC-9/MD-80 Aging Aircraft Service Action Requirements Document,''
McDonnell Douglas Report No. MDC-K1572. Therefore, in the interim
before replacement, the commenter suggests that operators should be
allowed to perform repetitive NDT inspections. Further, by performing
these inspections at the suggested interval, operators could accomplish
them at the same time that they conduct the inspections of the spoiler
links and fittings that currently are required by AD 85-01-03
[amendment 39-4977, (50 FR 2040, January 15, 1985).
The FAA does not concur. The commenter provided neither technical
data to justify the appropriateness of such inspections, nor suitable
inspection and repair procedures. Further, the FAA does not consider
that NDT inspections of the old pistons will necessarily enhance the
safety of these parts. The FAA maintains that long term continued
operational safety will be better assured by design changes to remove
the source of a problem altogether, rather than by repetitive
inspections. An understanding of the effectiveness of long term
repetitive inspections and the human factors associated with conducting
them, has led the FAA generally to consider placing less emphasis on
inspections and more emphasis on design improvements. The replacement
and installation requirements of this AD are
[[Page 3987]]
in consonance with these considerations.
Request To Allow Modification in Lieu of Replacement of Pistons
Two commenters request that the proposed rule be revised to provide
an option of modifying the actuator pistons instead of replacing them.
These commenters point out that McDonnell Douglas Service Bulletin 27-
183 was issued previously to address fatigue cracking in the inboard
and outboard spoiler actuator pistons. Among other things, that service
bulletin describes procedures for reworking the pistons by stress
coining the holes of the piston attach lug and installing fatigue
bushings in the holes. One of the commenters states that tests
conducted on actuator pistons that had been modified in accordance with
these procedures demonstrated an increase in the fatigue strength of
the piston over the original design by a factor of 10.
The FAA does not concur with the commenters' request. The FAA
acknowledges that testing did indicate that the stress coining
procedure described in Service Bulletin 27-183 appeared to stop the
cracking in the subject location. However, after this modification was
implemented on actuator pistons in service, other parts failed in new
locations; additional actions (such as dimensional changes) then had to
be taken to address those failures. In light of this, the FAA does not
find that the procedures described in Service Bulletin 27-183 are a
viable option in and of themselves.
Request To Revise Cost Impact Information
One commenter requests that the FAA revise the information it
provided concerning the estimated costs of replacing the pistons of the
outboard flight spoiler actuators with improved pistons. This commenter
contends that the FAA has underestimated the cost impact by a factor of
four for some operators. This commenter points out that many operators
will have to accomplish additional modifications of the actuator before
the new improved pistons can be installed. This commenter refers to the
modifications described in McDonnell Service Bulletin 27-240 (which
would entail approximately $780 in parts and labor) and Service
Bulletin 27-274 (which would entail approximately $110 in parts and
labor). The commenter requests that the costs associated with
performing the work specified in those service bulletins be included in
the cost estimates for the proposed AD.
The FAA does not consider that any revision to the cost estimate is
necessary. The FAA acknowledges that the actions specified in the two
service bulletins cited by the commenter must be accomplished prior to
(or in conjunction with) the installation of the improved pistons.
However, this AD requires only that the replacement action specified in
McDonnell Douglas Service Bulletin DC9-27-300 be accomplished.
Naturally, operators who have not already accomplished the other
modifications will encounter additional costs, but the FAA is not
mandating the other two service bulletins cited by the commenter.
Further, operators are not obligated to install the improved pistons;
that action is but one of two different actions provided by this AD.
Instead of that installation, operators can elect to install the
external protective doublers, as specified in paragraph (a)(1) of this
final rule, and may find that action to be more cost effective for
their operations.
Conclusion
After careful review of the available data, including the comments
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.
Cost Impact
There are approximately 1,571 Model DC-9, DC-9-80, and C-9
(military) series airplanes, and Model MD-88 airplanes of the affected
design in the worldwide fleet. The FAA estimates that 1,047 airplanes
of U.S. registry will be affected by this AD.
The required installation of external doublers will take
approximately 14 work hours per airplane to accomplish, at an average
labor rate of $60 per work hour. Required parts will cost approximately
$1,500 per airplane. Based on these figures, the cost impact of the
installation of external doublers required by this AD on U.S. operators
is estimated to be $2,340 per airplane. If all U.S. operators were to
elect to accomplish this installation, the cost impact of this AD would
be $2,449,980.
The required replacement of the pistons of the outboard flight
spoiler actuators will take approximately 12 work hours per airplane to
accomplish, at an average labor rate of $60 per work hour. Required
parts will cost approximately $5,180 per airplane. Based on these
figures, the cost impact of the replaced of the pistons required by
this AD on U.S. operators is estimated to be $5,900 per airplane. If
all U.S. operators were to elect to accomplish this replacement, the
cost impact of this AD would be $6,177,300.
The cost impact figures discussed above are 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. However, at least one affected U.S.
operator has advised the FAA that it has already accomplished the
actions required by this AD on the airplanes in its fleet. Therefore,
the future cost impact of this AD is expected to be less than the
figures indicated above.
Regulatory Impact
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:
[[Page 3988]]
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
97-02-08 McDonnell Douglas: Amendment 39-9893. Docket 96-NM-99-AD.
Applicability: Model DC-9, Model DC-9-80 and C-9 (military)
series airplanes, and Model MD-88 airplanes; as listed in McDonnell
Douglas Service Bulletin DC9-27-300, Revision 02, dated June 29,
1995; certificated in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
otherwise 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 fuel leakage and reduced structural integrity of the
wings due to puncturing of the wings by a failed piston of the
outboard flight spoiler actuator, accomplish the following:
(a) Prior to the accumulation of 5,000 landings after the
effective date of this AD, accomplish the actions specified in
either paragraph (a)(1) or (a)(2) of this AD, in accordance with
McDonnell Douglas Service Bulletin DC9-27-300, Revision 02, dated
June 29, 1995.
Note 2. Accomplishment of the actions specified in this
paragraph prior to the effective date of this AD in accordance with
the original issue or Revision 1 of McDonnell Douglas Service
Bulletin 27-300 is considered acceptable for compliance with this
paragraph.
Note 3: Installation of McDonnell Douglas flight spoiler
actuator assembly, part number (P/N) 5915900-5525, on the right and
left wings prior to the effective date of this AD is considered
acceptable for compliance with the requirements of this paragraph.
(1) Install external protective doublers between the outboard
flight spoiler actuators and the aft spar webs of the left and right
wings; or
(2) Replace the pistons of the outboard flight spoiler actuators
on the left and right wings with improved pistons.
(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, Los Angeles 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, Los Angeles ACO.
Note 4: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Los Angeles ACO.
(c) 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.
(d) Except as specified in NOTE 2 of this AD, the actions shall
be done in accordance with McDonnell Douglas Service Bulletin DC9-
27-300, Revision 02, dated June 29, 1995. 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 McDonnell Douglas Corporation, 3855 Lakewood
Boulevard, Long Beach, California 90846, Attention: Technical
Publications Business Administration, Department C1-L51 (2-60).
Copies may be inspected at the FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington; or at 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.
(e) This amendment becomes effective on March 4, 1997.
Issued in Renton, Washington, on January 14, 1997.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 97-1437 Filed 1-27-97; 8:45 am]
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