[Federal Register: March 20, 1998 (Volume 63, Number 54)]
[Proposed Rules]               
[Page 13579-13581]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr20mr98-43]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-20-AD]
RIN 2120-AA64

 
Airworthiness Directives; McDonnell Douglas Model DC-9-80 Series 
Airplanes and Model MD-88 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain McDonnell Douglas Model 
DC-9-80 series airplanes and Model MD-88 airplanes. This proposal would 
require repetitive inspections to detect fatigue cracking of certain 
fuselage skin panels, and repair, if necessary. For certain airplanes, 
the proposed AD also provides for an optional preventative 
modification, which, if accomplished, would terminate the repetitive 
inspections. This proposal is prompted by reports of fatigue cracking 
of certain fuselage skin panels. The actions specified by the proposed 
AD are intended to prevent such fatigue cracking, which could result in 
reduced structural integrity of the airplane, and consequent loss of 
pressurization.

DATES: Comments must be received by May 4, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-20-AD, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056. Comments may be inspected at this location 
between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal 
holidays.
    The service information referenced in the proposed rule may be 
obtained from The Boeing Company, Douglas Products Division, 3855 
Lakewood Boulevard, Long Beach, California 90846, Attention: Technical 
Publications Business Administration, ept. C1-L51 (2-60). This 
information may be examined 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.

FOR FURTHER INFORMATION CONTACT: Brent Bandley, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California 90846; telephone 
(562) 627-5237; 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.
    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 97-NM-20-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. 97-NM-20-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports indicating that fatigue cracking of 
the fuselage skin has been detected on several McDonnell Douglas Model 
DC-9-30 series airplanes. The cracking was located along the line of 
attachments that secure the fuselage skin to longeron 22. The cracking 
emanated from multiple attachment holes at 45-degree angles. On one 
airplane, cracking extended for approximately 12 inches in length. 
Investigation and laboratory analysis of skin segments have revealed 
that the cracking was due to material fatigue. Furthermore, during 
repair of one airplane, additional damage was

[[Page 13580]]

found on longerons 23L and 24L at station Y=200.000. The affected 
airplanes had accumulated between 44,618 and 74,043 flight hours, and 
45,210 and 88,093 landings at the time of inspection. Fatigue cracking 
of certain fuselage skin panels, if not detected and corrected in a 
timely manner, could result in reduced structural integrity of the 
airplane, and consequent loss of pressurization.

Explanation of Relevant Service Information

    The FAA has reviewed and approved McDonnell Douglas MD-80 Service 
Bulletin 53-253, dated March 31, 1994. The service bulletin describes 
procedures for performing repetitive high frequency eddy current (HFEC) 
inspections to detect fatigue cracking of the forward lower left 
fuselage skin panels between stations Y=160.000 and Y=200.000; and 
repair, if necessary. The service bulletin describes procedures for a 
permanent repair for cracking within certain limitations, which would 
eliminate the need for repetitive HFEC inspections. Additionally, the 
service bulletin describes procedures for an optional preventative 
modification for airplanes on which no cracking is detected. The 
preventative modification includes cold working holes and installing 
oversize fasteners, which would minimize the possibility of cracking. 
Accomplishment of the preventative modification would eliminate the 
need for the repetitive HFEC inspections.

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 require repetitive HFEC inspections to detect fatigue 
cracking of the forward lower left fuselage skin panels between station 
Y=160.000 and Y=200.000; and repair, if necessary. The proposed AD also 
provides for an optional preventative modification for airplanes on 
which no cracking is detected, which, if accomplished, would terminate 
the repetitive inspections. The actions would be required to be 
accomplished in accordance with the service bulletin described 
previously.

Differences Between this Rule and the Relevant Service Bulletin

    Operators should note that, although the service bulletin 
recommends contacting the manufacturer for any cracking that extends 
forward of frame station Y=160.000 or aft of station Y=200.000, this 
proposed AD requires that such cracking be repaired in accordance with 
a method approved by the FAA.

Cost Impact

    There are approximately 1,200 McDonnell Douglas Model DC-9-80 and 
Model MD-88 airplanes of the affected design in the worldwide fleet. 
The FAA estimates that 800 airplanes of U.S. registry would be affected 
by this proposed AD, that it would take approximately 24 work hours per 
airplane to accomplish the proposed inspection, and that the average 
labor rate is $60 per work hour. Based on these figures, the cost 
impact of the proposed inspection on U.S. operators is estimated to be 
$1,152,000, or $1,440 per airplane, per inspection cycle.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the 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 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    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 adding the following new 
airworthiness directive:

McDonnell Douglas:  Docket 97-NM-20-AD.

    Applicability: Model DC-9-80 series airplanes and Model MD-88 
airplanes, as listed in McDonnell Douglas Service Bulletin 53-253, 
dated March 31, 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 request approval for an 
alternative method of compliance in accordance with paragraph (e) 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 loss of pressurization due to reduced structural 
integrity of the airplane, accomplish the following:
    (a) Prior to the accumulation of 44,500 total landings, or 
within 4,500 landings after the effective date of this AD, whichever 
occurs later: Perform a high frequency eddy current (HFEC) 
inspection to detect fatigue cracking of the fuselage skin panels 
between stations Y=160.000 and Y=200.000 at the left side of 
longeron 22 below the airstair door cutout, in accordance with 
McDonnell Douglas Service Bulletin 53-253, dated March 31, 1994.
    (b) If no cracking is detected, accomplish the actions specified 
in either paragraph (b)(1) or (b)(2) of this AD, in accordance with 
McDonnell Douglas Service Bulletin 53-253, dated March 31, 1994, at 
the time specified.
    (1) Perform the inspection required by paragraph (a) of this AD 
thereafter at intervals not to exceed 4,500 landings until the 
requirements of paragraph (b)(2) of this AD have been accomplished. 
Or,
    (2) Prior to further flight, install the preventative 
modification in accordance with the service bulletin. Accomplishment 
of the preventative modification prior to detection of any cracking 
constitutes terminating action for the repetitive inspection 
requirements of this AD.
    (c) If any cracking is detected within frame stations Y=160.000 
and Y=200.000, accomplish the actions specified in either paragraph 
(c)(1) or (c)(2) of this AD, in

[[Page 13581]]

accordance with McDonnell Douglas Service Bulletin 53-253, dated 
March 31, 1994.
    (1) Accomplish the actions specified in paragraphs (c)(1)(i), 
(c)(1)(ii), (c)(1)(iii), and (c)(1)(iv) of this AD at the times 
specified.
    (i) Prior to further flight, install the temporary repair in 
accordance with the service bulletin.
    (ii) Within 3,000 landings after installation of the temporary 
repair, and thereafter, at intervals not to exceed 3,000 landings, 
perform visual inspections to detect cracking of the repaired area, 
in accordance with the service bulletin.
    (iii) Within 4,500 landings after installation of the temporary 
repair, and thereafter, at intervals not to exceed 4,500 landings, 
perform HFEC inspections to detect cracking of any area not covered 
by the temporary doubler repair, in accordance with the service 
bulletin.
    (iv) Within 8,000 landings after installation of the temporary 
repair, accomplish the permanent repair in accordance with the 
service bulletin. Accomplishment of the permanent repair constitutes 
terminating action for the repetitive inspection requirements of 
this AD.
    (2) Prior to further flight, accomplish the permanent repair in 
accordance with the service bulletin. Accomplishment of the 
permanent repair constitutes terminating action for the repetitive 
inspection requirements of this AD.
    (d) If any cracking is detected that extends forward of station 
Y=160.000 or aft of station Y=200.000, prior to further flight, 
repair in accordance with a method approved by the Manager, Los 
Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane 
Directorate.
    (e) 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 ACO. 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.

    (f) 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 March 13, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-7229 Filed 3-19-98; 8:45 am]
BILLING CODE 4910-13-P