[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]
BILLING CODE 4910-13-U