[Federal Register Volume 62, Number 22 (Monday, February 3, 1997)]
[Rules and Regulations]
[Pages 4906-4908]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-2222]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-235-AD; Amendment 39-9911; AD 97-03-05]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-9 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 McDonnell Douglas DC-9 series airplanes, 
that currently requires repetitive visual inspections to detect 
corrosion and cracking of the fuselage upper skin and frames in the 
area of the loop antenna assemblies of the automatic direction finder 
(ADF), and repair, if necessary. This amendment adds a requirement to 
perform a visual and an eddy current inspection of the fuselage forward 
upper skin under the antennas, followed by the reinstallation of the 
ADF antennas using an improved procedure. This amendment is prompted by 
the development of a modification of the ADF antenna installation that 
constitutes terminating action for the required repetitive visual 
inspections. The actions specified by this AD are intended to prevent 
rapid decompression of the fuselage, significant structural damage, and 
subsequent reduced structural integrity of the airplane, due to 
problems associated with corrosion and fatigue cracking in the subject 
area.

DATES: Effective March 10, 1997.
    The incorporation by reference of McDonnell Douglas Alert Service 
Bulletin DC9-53A282, dated March 20, 1996, listed in the regulations, 
was approved previously by the Director of the Federal Register, in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51, as of April 15, 1996 
(61 FR 15882, April 10, 1996).
    The incorporation by reference of McDonnell Douglas Service 
Bulletin DC9-53-284, dated August 20, 1996, listed in the regulations, 
is approved by the Director of the Federal Register as of March 10, 
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: Wahib Mina, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone 
(310) 627-5324; fax (310) 627-5210.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 96-07-51, 
amendment 39-9562 (61 FR 15882, April 10, 1996), which is applicable to 
certain McDonnell Douglas DC-9 series airplanes, was published in the 
Federal Register on October 23, 1996 (61 FR 54969). That action 
proposed to continue to require repetitive internal

[[Page 4907]]

visual inspections to detect corrosion and cracking of the fuselage 
forward upper skin and to detect cracking of the fuselage frame in the 
area of the forward and aft loop antenna assemblies of the automatic 
direction finder (ADF), as is currently required by AD 97-07-01. 
However, it also proposed to add a requirement to perform a visual and 
an eddy current inspection of the fuselage forward upper skin under the 
antennas, followed by the reinstallation of the ADF antennas using an 
improved procedure. Accomplishment of these actions would constitute 
terminating action for the required repetitive inspections.
    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

    Five commenters support the proposed AD.

Request To Extend Compliance Time for Certain Airplanes

    One commenter supports the intent of the proposal, but requests 
that the compliance time for accomplishing the terminating action be 
extended from the proposed 24 months to 48 months for those airplanes 
on which the antenna has been reinstalled within the past 4 years. The 
commenter notes that the compliance schedule for the terminating action 
does not address the condition where the ADF antenna was previously 
removed and the fuselage skin inspection and repaired, i.e., in 
accordance with the previously issued AD 96-07-51. The commenter 
considers that, for the repaired airplanes, a higher level of safety 
has been achieved than if no such repair had been performed. 
Considering the number of airplanes that are affected by this AD 
(approximately 403), allowing an extension of the time for installing 
the final fix on the previously repaired airplanes also will minimize 
the operational impact of the AD on operators.
    The FAA concurs with the commenter's request. The FAA acknowledges 
that AD 96-07-51 (as well as this new AD) requires that, if any 
cracking or corrosion is found and it is within certain limits, the 
area must be repaired in accordance with either the Structural Repair 
Manual (SRM) or a manner approved by the FAA. In consideration of the 
increased structural integrity of the area that is provided by such 
repairs, the FAA finds that the risk of additional cracking is reduced 
and accomplishment of the terminating action may be extended for an 
additional 2 years (for a total of 4 years) without adversely affecting 
safety. Paragraph (b) of the final rule has been revised accordingly.

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 change previously 
described. The FAA has determined that this change will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    There are approximately 569 McDonnell Douglas Model DC-9 series 
airplanes of the affected design in the worldwide fleet. The FAA 
estimates that 403 airplanes of U.S. registry will be affected by this 
proposed AD.
    The inspections that were previously required by AD 96-07-51 and 
retained in this new AD take approximately 5 work hours per airplane to 
accomplish, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact of the currently required actions on 
U.S. operators is estimated to be $120,900, or $300 per airplane, per 
inspection.
    The terminating action that is required by this new AD will take 
approximately 16 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of the new requirements of this AD on U.S. operators is 
estimated to be $386,880, or $960 per airplane.
    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.

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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-9562 (61 FR 
15882, April 10, 1996), and by adding a new airworthiness directive 
(AD), amendment 39-9911, to read as follows:

97-03-05  McDonnell Douglas: Amendment 39-9911. Docket 96-NM-235-AD. 
Supersedes AD 96-07-51, Amendment 39-9562.

    Applicability: Model DC-9 series airplanes having fuselage 
numbers 001 through 631 inclusive, 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 otherwise 
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 (d)(1) 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 rapid decompression of the fuselage, significant 
structural damage, and subsequent reduced structural integrity of 
the airplane, due to problems associated with

[[Page 4908]]

corrosion and fatigue cracking, accomplish the following:
    (a) Within 15 days after April 15, 1996 (the effective date of 
AD 96-07-51, amendment 39-9562): Perform an internal visual 
inspection to detect corrosion and cracking of the fuselage forward 
upper skin and to detect cracking of the fuselage frame in the area 
of the forward and aft loop antenna assemblies of the automatic 
direction finder (ADF), in accordance with McDonnell Douglas Alert 
Service Bulletin DC9-53A282, dated March 20, 1996.
    (1) If no corrosion or cracking is detected: Repeat the visual 
inspection required by paragraph (a) of this AD thereafter at 
intervals not to exceed 6 months.
    (2) If any corrosion or cracking is detected that is within the 
limits specified in Chapter 53-04, Figure 29, of the DC-9 Structural 
Repair Manual (SRM): Prior to further flight, repair in accordance 
with Chapter 53-04, Figure 29, of the SRM. Thereafter, repeat the 
visual inspection required by paragraph (a) of this AD at intervals 
not to exceed 6 months.
    (3) If any corrosion or cracking is detected in the fuselage 
forward upper skin, or if any cracking is detected in the fuselage 
frame, and that corrosion or cracking is outside the limits 
specified in Chapter 53-04, Figure 29, of the SRM: Prior to further 
flight, repair in accordance with a method approved by the Manager, 
Los Angeles Aircraft Certification Office (ACO), FAA, Transport 
Airplane Directorate.
    (b) At the applicable time specified in paragraph (b)(1) of 
(b)(2) of this AD, remove the ADF antennas and perform both a visual 
inspection and a high frequency eddy current inspection to detect 
corrosion and cracking of the fuselage forward upper skin under the 
antennas, in accordance with McDonnell Douglas Service Bulletin DC9-
53-284, dated August 20, 1996.
    (1) For airplanes on which the ADF antenna has not been 
previously removed and the fuselage skin has not been previously 
inspected for evidence of corrosion, within the last 4 years prior 
to the effective date of this AD: Accomplish the inspections within 
2 years after the effective date of this AD.
    (2) For airplanes on which the ADF antenna has been previously 
removed and the fuselage skin has been previously inspected for 
evidence of corrosion and/or repaired within the last 4 years prior 
to the effective date of this AD: Accomplish the inspections within 
4 years after the effective date of this AD.
    (c) As a result of the inspections required by paragraph (b) of 
this AD, accomplish the applicable action specified in paragraph 
(c)(1), (c)(2), or (c)(3) of this AD. Accomplishment of the actions 
specified in paragraph (c)(1) or (c)(2) constitutes terminating 
action for the requirements of paragraphs (a)(1) and (a)(2) of this 
AD.
    (1) If no cracking or corrosion is detected: Prior to further 
flight, reinstall the ADF antennas using the improved installation 
procedure in accordance with McDonnell Douglas Service Bulletin DC9-
53-284, dated August 20, 1996. Thereafter, no further action is 
required by this AD.
    (2) If any cracking or corrosion is detected that is within the 
limits specified in Chapter 53-04 of the DC-9 Structural Repair 
Manual (SRM): Prior to further flight, repair in accordance with 
Chapter 53-04 of the DC-9 SRM, and reinstall the ADF antennas using 
the improved installation procedure in accordance with McDonnell 
Douglas Service Bulletin DC9-53-284, dated August 20, 1996. 
Thereafter, no further action is required by this AD.
    (3) If any cracking or corrosion is detected that is outside the 
limits specified in Chapter 53-04 of the SRM: Prior to further 
flight, repair in accordance with a method approved by the Manager, 
Los Angeles Certification Office (ACO), FAA, Transport Airport 
Directorate.
    (d)(1) 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.

    (2) Alternative methods of compliance, approved in accordance 
with AD 96-07-71, amendment 39-9562, are approved as alternative 
methods of compliance with this AD.
    (e) 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.
    (f) The actions shall be done in accordance with McDonnell 
Douglas Alert Service Bulletin DC9-53A282, dated March 20, 1996; and 
McDonnell Douglas Service Bulletin DC9-53-284, dated August 20, 
1996. The incorporation by reference of the former service bulletin 
was approved previously by the Director of the Federal Register, in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51, as of April 15, 
1996 (61 FR 15882, April 10, 1996). The incorporation by reference 
of the latter service bulletin 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.
    (g) This amendment becomes effective on March 10, 1997.

    Issued in Renton, Washington, on January 23, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-2222 Filed 1-31-97; 8:45 am]
BILLING CODE 4910-13-U