[Federal Register Volume 65, Number 129 (Wednesday, July 5, 2000)]
[Proposed Rules]
[Pages 41385-41387]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-16927]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-04-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain McDonnell Douglas 
Model DC-9-10, -20, -30, -40, and -50 series airplanes, that currently 
requires repetitive radiographic and ultrasonic or eddy current 
inspections, and modification of the upper cap of the front spar of the 
left and right engine pylons, if necessary. This action would require 
new, improved x-ray and eddy current inspections to detect cracks of 
the upper cap of the front spar of the left and right engine pylons, 
and repetitive inspections or corrective actions, if necessary. This 
action also would require modification of the subject area, which would 
constitute terminating action for the repetitive inspection 
requirements. This proposal is prompted by additional reports of 
fatigue cracking in the subject area of these airplanes. The actions 
specified by the proposed AD are intended to prevent failure of the 
upper cap of the front spar of the engine pylons due to fatigue 
cracking, and consequent reduced structural integrity of the airplane.

DATES: Comments must be received by August 21, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-04-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be submitted via fax to 
(425) 227-1232. Comments may also be sent via the Internet using the 
following address: [email protected]. Comments sent via fax or 
the Internet must contain ``Docket No. 2000-NM-04-AD'' in the subject 
line and need not be submitted in triplicate. Comments sent via the 
Internet as attached electronic files must be formatted in Microsoft 
Word 97 for Windows or ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Aircraft Group, Long Beach Division, 
3855 Lakewood Boulevard, Long Beach, California 90846, Attention: 
Technical Publications Business Administration, Dept. C1-L51 (2-60). 
This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the the 
FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT: Wahib Mina, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los 
Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California 90712-4137; telephone (562) 627-5324; fax (562) 
627-5210.

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.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    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 2000-NM-04-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-114, Attention: Rules 
Docket No. 2000-NM-04-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    In 1977, the FAA issued AD 77-44-19, amendment 39-2971, applicable 
to certain McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 
series airplanes, to require repetitive radiographic and ultrasonic or 
eddy current inspections, and modification of the upper cap of the 
front spar of the left and right engine pylons, if necessary. The 
requirements of that AD are intended to detect fatigue cracks and/or 
failure of the upper cap of the front spar of the left and right engine 
pylons.

Actions Since Issuance of Previous Rule

    Since the issuance of AD 77-14-19, the FAA has received additional 
reports of fatigue cracking in the subject area of the upper cap of the 
front spar of the left and right engine pylons. The airplanes on which 
the cracking occurred had accumulated between 10,162 and 23,850 total 
flight hours. Investigation revealed that the repetitive ultrasonic and 
eddy current inspections, as required by AD 77-14-19, do not adequately 
detect fatigue cracking in the subject area. Such fatigue cracking, if 
not detected and corrected, could result in failure of the upper cap of 
the front spar of the left and right engine pylons, and consequent 
reduced structural integrity of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved McDonnell Douglas Service 
Bulletin DC9-54-030, Revision 06, dated November 11, 1999. The service 
bulletin describes procedures for x-ray and eddy current inspections to 
detect cracks of the upper cap of the front spar of the left and right 
engine pylons, and repetitive inspections or corrective actions (i.e., 
the modification described below), if necessary. The service bulletin 
also describes procedures for an optional modification of the upper cap 
of the front spar of the left and right engine pylons, which would 
eliminate the need for the repetitive inspections.

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Accomplishment of the actions specified in the service bulletin is 
intended to adequately address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would supersede AD 77-14-19 to continue to require 
radiographic and ultrasonic or eddy current inspections. The proposed 
AD also would require accomplishment of the actions specified in the 
service bulletin described previously, except as discussed below.

Differences Between the Proposed AD and Relevant Service 
Information

    Operators should note that this AD proposes to mandate, prior to 
the accumulation of 100,000 total landings, or within 6 months after 
the effective date of this AD, whichever occurs later, the modification 
of the upper cap of the front spar of the left and right engine pylons 
described in McDonnell Douglas Service Bulletin DC9-54-030, Revision 
06, as terminating action for the repetitive inspections. 
(Incorporation of the terminating action is specified in this service 
bulletin as optional).
    The FAA has determined that long-term continued operational safety 
will be better assured by design changes to remove the source of the 
problem, rather than by repetitive inspections. Long-term inspections 
may not be providing the degree of safety assurance necessary for the 
transport airplane fleet. This, coupled with a better understanding of 
the human factors associated with numerous continual inspections, has 
led the FAA to consider placing less emphasis on inspections and more 
emphasis on design improvements. The proposed modification requirement 
is consistent with these conditions.

Explanation of Change of Applicability

    The applicability of AD 77-14-19 includes affected airplanes having 
fuselage numbers 1 through 837. However, the applicability of this 
proposed AD removes several of those fuselage numbers because those 
airplanes are out of service.

Cost Impact

    There are approximately 809 Model DC-9-10, -20, -30, -40, and -50 
series airplanes and C-9 (military) airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 572 airplanes of U.S. 
registry would be affected by this proposed AD.
    The actions that are currently required by AD 77-14-19, and 
retained in this proposed AD, take approximately 12 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 $411,840, or $720 per 
airplane, per inspection cycle.
    The new inspection that is proposed in this AD action would take 
approximately 12 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of this inspection proposed by this AD on U.S. operators is 
estimated to be $411,840, or $720 per airplane, per inspection cycle.
    The new modification that is proposed in this AD action would take 
approximately 110 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts would cost 
approximately $30,496 per airplane. Based on these figures, the cost 
impact of the modification proposed by this AD on U.S. operators is 
estimated to be $21,218,912, or $37,096 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the current or proposed 
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 proposed herein would not have a substantial direct 
effect 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, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-2971, and by 
adding a new airworthiness directive (AD), to read as follows:

McDonnell Douglas: Docket 2000-NM-04-AD. Supersedes AD 77-14-19, 
Amendment 39-2971.

    Applicability: Model DC-9-10, -20, -30, -40, and -50 series 
airplanes and C-9 (military) airplanes; as listed in McDonnell 
Douglas Service Bulletin DC9-54-030, Revision 06, dated November 11, 
1999; certificated in any category; except for those airplanes on 
which Special Change Notification 1269A, dated August 11, 1965, or 
Service Rework Drawing SR09540004, Change ``E,'' dated September 21, 
1992, Change ``F,'' dated April 19, 1995, Change ``G,'' dated May 6, 
1997, or Change ``H,'' dated July 12, 1997, has been accomplished.

    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 (g) 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 failure of the front spar attachment and upper cap of 
the engine pylons due to fatigue cracking, and consequent reduced 
structural integrity of the airplane, accomplish the following:

Repetitive Inspections

    (a) Prior to the accumulation of 9,800 total flight hours, or 
within the next 1,800 flight hours after August 23, 1977 (the 
effective date of AD 77-14-19, amendment 39-2971), whichever occurs 
later, unless accomplished previously within the last 1,800 flight 
hours, accomplish the radiographic and ultrasonic

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or eddy current inspections in accordance with the instructions in 
Douglas Service Bulletin 54-30, dated January 19, 1977. Repeat the 
inspection thereafter at intervals not to exceed 3,600 flight hours. 
For those operators who have conducted only the radiographic 
inspections in accordance with Douglas All Operators Letter AOL 9-
835, dated October 30, 1974, perform the ultrasonic or eddy current 
inspections, and thereafter, the radiographic and ultrasonic or eddy 
current inspection in accordance with the requirements of this AD, 
as applicable.

    Note 2: Inspections accomplished prior to the effective date of 
this AD in accordance with McDonnell Douglas Service Bulletin 54-30, 
Revision 1, dated June 29, 1977, Revision 2, dated October 27, 1978, 
Revision 3, dated April 30, 1986, or Revision 4, dated March 25, 
1991; or McDonnell Douglas Service Bulletin DC9-54-030, Revision 05, 
dated August 26, 1999, or Revision 06, dated November 11, 1999; are 
considered acceptable for compliance with the inspections required 
by paragraph (a) of this AD.

Initial Inspections and Follow-On/Corrective Action

    (b) For airplanes on which the modification specified in 
paragraph (e) of this AD has not been accomplished: Prior to the 
accumulation of 8,000 total flight hours or within 3,600 flight 
hours after the effective date of this AD, whichever occurs later, 
perform x-ray and eddy current inspections to detect cracks of the 
upper cap of the front spar of the left and right engine pylons, in 
accordance with McDonnell Douglas Service Bulletin DC9-54-030, 
Revision 06, dated November 11, 1999. Accomplishment of these 
inspections constitutes terminating action for the repetitive 
inspection requirements of paragraph (a) of this AD.

No Crack Detected: Repetitive Inspections

    (c) If no crack is detected during any inspection required by 
paragraph (a) or (b) of this AD, repeat the inspections thereafter 
at intervals not to exceed 3,600 flight hours until the modification 
required by paragraph (e) of this AD is accomplished.

Any Crack Detected: Modification

    (d) If any crack is detected during any inspection required by 
paragraph (a) or (b) of this AD, prior to further flight, accomplish 
the modification specified in paragraph (e) of this AD.

Terminating Modification

    (e) Except as provided by paragraph (d) of this AD, prior to the 
accumulation of 100,000 total landings, or within 6 months after the 
effective date of this AD, whichever occurs later, modify the upper 
cap of the front spar of the left and right engine pylons in 
accordance with McDonnell Douglas Service Bulletin DC9-54-030, 
Revision 06, dated November 11, 1999. Accomplishment of this 
modification constitutes terminating action for the requirements of 
this AD.

    Note 3: Accomplishment of the modification of the upper cap of 
the front spar of the left and right engine pylons prior to the 
effective date of this AD in accordance with Douglas Service 
Bulletin 54-30, Revision 4, dated March 25, 1991, or McDonnell 
Douglas Service Bulletin DC9-54-030, Revision 5, dated August 26, 
1999; is considered acceptable for compliance with the modification 
specified in paragraph (e) of this AD.

    (f) Accomplishment of the terminating modification required by 
paragraph (e) of this AD constitutes compliance with the actions 
specified in McDonnell Douglas Service Bulletin 54-30, Revision 4, 
dated March 25, 1991, as required by AD 96-10-11, amendment 39-9618 
(61 FR 24675, May 16, 1996) [which references ``DC-9/MD-80 Aging 
Aircraft Service Action Requirements Document'' (SARD), McDonnell 
Douglas Report MDC K1572, Revision B, dated January 15, 1993].

Alternative Methods of Compliance

    (g) 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.

Special Flight Permits

    (h) 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 June 27, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-16927 Filed 7-3-00; 8:45 am]
BILLING CODE 4910-13-P