[Federal Register Volume 60, Number 31 (Wednesday, February 15, 1995)]
[Rules and Regulations]
[Pages 8542-8543]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-2176]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-144-AD; Amendment 39-9133; AD 95-02-14]


Airworthiness Directives; McDonnell Douglas Model DC-9-10, -20, -
30, -40, and -50 Series Airplanes, and Model C-9 (Military) Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain McDonnell Douglas Model DC-9-10, -20, -30, -40, 
and -50 series airplanes, and Model C-9 (military) airplanes, that 
requires replacement of the engine nose cowl attaching bolts and the 
installation of bearing plates on the nose cowl attach ring. This 
amendment is prompted by incidents in which the nose cowl separated 
from the airplane due to the elongation and/or breakout of the nose 
cowl's attachment ring holes, and failure of the attaching bolts. The 
actions specified by this AD are intended to prevent separation of the 
engine nose cowl from the airplane, which could result in damage to the 
airplane structure or could present a hazard to persons or property on 
the ground.

DATES: Effective March 17, 1995.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 17, 1995.

ADDRESSES: The service information referenced in this AD may be 
obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach, 
California 90801-1771, Attention: Business Unit Manager, Technical 
Administrative Support, Dept. L51, M.C. 2-98. 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, Los Angeles Aircraft Certification Office, 
Transport Airplane Directorate, 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: Robert Baitoo, Aerospace Engineer, 
Propulsion Branch, ANM-140L, FAA, Los Angeles Aircraft Certification 
Office, Transport Airplane Directorate, 3960 Paramount Boulevard, 
Lakewood, California 90712-4137; telephone (310) 627-5245; 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-9-10, -20, -30, -40, and -50 series airplanes, and Model C-9 
(military) airplanes, was published in the Federal Register on October 
18, 1994 (59 FR 52483). That action proposed to require replacement of 
the engine nose cowl attaching bolts and the installation of bearing 
plates on the nose cowl attach ring.

Discussion of Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter supports the proposal.
    Two commenters request that the proposed compliance time of 12 
months for replacement be extended so that the required action can be 
accomplished during regularly scheduled maintenance activities. One 
commenter suggests a compliance time of 18 months; the other commenter 
suggest a compliance time of 3,000 hours time-in-service. The FAA 
concurs that the compliance time can be extended somewhat. 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 required parts 
and the practical aspect of accomplishing the required replacement on 
the affected fleet in a timely manner. The FAA's intent was that the 
replacement be conducted during a regularly scheduled maintenance visit 
for the majority of the affected fleet, when the airplanes would be 
located at a base where special equipment and trained personnel would 
be readily available, if necessary. Based on the information supplied 
by the commenters, the FAA now recognizes that 18 months corresponds 
more closely to the interval representative of most of the affected 
operators' normal maintenance schedules. Paragraph (a) of the final 
rule has been revised to reflect a compliance time of 18 months. The 
FAA does not consider that this extension will adversely affect safety.
    One commenter questions the FAA's estimate of the cost of required 
replacement parts. The commenter states that the $1,200 per airplane 
figure, presented in the cost impact information in the preamble to the 
notice, is too low. This commenter suggests that parts costs will be 
approximately $15,700 per airplane. Upon further review, the FAA 
concurs that the cost of required parts may be more than what was 
previously estimated. The manufacturer has provided updated cost 
figures for replacement bearing plates and bolts. If these items are 
purchased directly from the manufacturer, the cost of replacement 
bearing plates may be as much as $13,284 (36 plates at $369 each), and 
the cost of replacement bolts may be as much as $1,900 (38 bolts at $50 
each). However, the FAA points out that bearing plates can be 
fabricated locally at a nominal cost, and bolts can be procured from 
the operator's current stock, thereby reducing parts costs 
considerably. The FAA has revised the cost impact information, below, 
to include this updated information on the cost of required parts.

Discussion of Additional Changes to the Rule

    Since issuance of the notice, the FAA has reviewed and approved 
Revision 1 to McDonnell Douglas DC-9 Service Bulletin A71-63, dated 
December 15, 1994. This revision is essentially identical to the 
originally issued service bulletin, which was referenced in the notice 
as the appropriate source of service information; however, it contains 
certain editorial revisions and additional nose cowl part numbers. The 
FAA has revised the final rule to include this revision of the service 
bulletin as an additional source of service information.
    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 added to this final rule to clarify this requirement. 
[[Page 8543]] 
    Additionally, the FAA has recently reviewed the figures it has used 
over the past several years in calculating the economic 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 cost impact information, below, has been 
revised to reflect this increase in the specified hourly labor rate.
    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 892 Model DC-9-10, -20, -30, -40, and -50 
series airplanes, and Model C-9 (military) airplanes of the affected 
design in the worldwide fleet. The FAA estimates that 557 airplanes of 
U.S. registry will be affected by this AD.
    It will take approximately 6 work hours per airplane to accomplish 
the required replacement actions, at an average labor rate of $60 per 
work hour. Required parts will vary in price, depending upon whether 
they are purchased from the manufacturer, manufactured locally, or 
procured from the operator's existing stocks. If all required parts (36 
bearing plates and 38 bolts) are purchased from the manufacturer, the 
cost could be as much as $15,184 per airplane. However, if the bearing 
plates are manufactured locally and bolts are retrieved from the 
operator's current stock, the estimated costs will be considerably 
lower, approximately $1,900 per airplane.
    Based on these figures, the total cost impact of the AD on U.S. 
operators is estimated to be between $1,258,820 (or $2,260 per 
airplane) and $8,658,008 (or $15,544 per airplane). This total cost 
impact figure 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.

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:

    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 adding the following new 
airworthiness directive:

95-02-14  McDonnell Douglas: Amendment 39-9133. Docket 94-NM-144-AD.

    Applicability: Model DC-9-10, -20, -30, -40, and -50 series 
airplanes, and Model C-9 (military) airplanes; as listed in 
McDonnell Douglas DC-9 Alert Service Bulletin A71-63, dated July 21, 
1994; 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 (b) 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 separation of the engine nose cowl from the airplane, 
accomplish the following:
    (a) Within 18 months after the effective date of this AD, 
replace the left and right engine nose cowl attaching bolts and 
install bearing plates, in accordance with McDonnell Douglas DC-9 
Alert Service Bulletin A71-63, dated July 21, 1994; or Revision 1, 
dated December 15, 1994.
    (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 2: 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 
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.
    -(d) The replacement shall be done in accordance with McDonnell 
Douglas DC-9 Alert Service Bulletin A71-63, dated July 21, 1994; or 
McDonnell Douglas DC-9 Alert Service Bulletin A71-63, Revision 1, 
dated December 15, 1994. 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, P.O. Box 1771, Long Beach, California 
90801-1771, Attention: Business Unit Manager, Technical 
Administrative Support, Dept. L51, M.C. 2-98. Copies may be 
inspected at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington; or at the FAA, Los Angeles Aircraft 
Certification Office, Transport Airplane Directorate, 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 17, 1995.

    Issued in Renton, Washington, on January 24, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-2176 Filed 2-14-95; 8:45 am]
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