[Federal Register Volume 62, Number 38 (Wednesday, February 26, 1997)]
[Proposed Rules]
[Pages 8644-8646]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-4714]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-272-AD]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-9-10, -15, 
and -30 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 adoption of a new airworthiness 
directive (AD) that is applicable to certain McDonnell Douglas Model 
DC-9-10, -15, and -30 series airplanes, and C-9 (military) airplanes. 
This proposal would require a one-time visual inspection to determine 
if all corners of the upper cargo doorjamb have been previously 
modified, various follow-on repetitive inspections, and modification, 
if necessary. This proposal is prompted by reports of fatigue cracks 
found in the fuselage skin and doubler at the corners of the upper 
cargo doorjamb. The actions specified by the proposed AD are intended 
to detect and correct such fatigue cracking, which could result in 
rapid decompression of the fuselage and consequent reduced structural 
integrity of the airplane.

DATES: Comments must be received by April 7, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-272-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 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 FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington.

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:

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 96-NM-272-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-103, Attention: Rules 
Docket No. 96-NM-272-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports of fatigue cracks in the fuselage skin 
and doubler at the corners of the upper cargo doorjamb on Model DC-9 
series airplanes. These cracks were discovered during inspections 
conducted as part of the Supplemental Structural Inspection Document 
(SSID) program, required by AD 96-13-03, amendment 39-9671 (61 FR 
31009, June 19, 1996). Investigation revealed that such cracking was 
caused by fatigue-related stress. Fatigue cracking in the fuselage skin 
or doubler at the corners of the upper cargo doorjamb, if not detected 
and corrected in a timely manner, could result in rapid decompression 
of the fuselage and consequent reduced structural integrity of the 
airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved McDonnell Douglas Service 
Bulletin DC9-53-276, dated September 30, 1996. The service bulletin 
describes the following procedures:
    1. For airplanes on which the modification specified in Service 
Bulletin DC9-53-276 has not been accomplished: Performing x-ray 
inspections to detect cracks of the fuselage skin and doubler at all 
corners of the upper cargo doorjamb;
    2. Conducting repetitive inspections, or modifying the corner skin 
of the upper cargo doorjamb and performing follow-on action eddy 
current inspections, if no cracking is detected;

[[Page 8645]]

    3. Performing repetitive eddy current inspections to detect cracks 
on the skin adjacent to any corner that has been modified; and
    4. Modifying any crack that is found to be 2 inches or less in 
length at all corners that have not been modified and performing 
follow-on repetitive eddy current inspections.
    Accomplishment of the modification will minimize the possibility of 
cracks in the fuselage skin and doubler.

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 a one-time visual inspection to determine if 
all corners of the upper cargo doorjamb have been previously modified, 
various follow-on repetitive inspections, and modification, if 
necessary. The follow-on repetitive inspections would be required to be 
accomplished in accordance with the service bulletin described 
previously.

Differences Between the Proposed Rule and the Relevant Service 
Information

    The referenced service bulletin recommends performing an initial x-
ray inspection in the fuselage skin and doubler at all corners of the 
upper cargo doorjamb. However, the FAA is unaware of the existence of 
an adequate x-ray inspection method for inspecting corners that have 
been modified. Therefore, for cases where the corners of the upper 
cargo doorjamb have been modified, the proposed AD would require an 
eddy current inspection to detect cracks on skin adjacent to the 
modification. For cases where the corners of the upper cargo doorjamb 
have not been modified, the proposed AD would require an x-ray 
inspection, as described previously. Since these inspections are 
dependent on whether the corners have been modified or not, the FAA 
finds that an initial one-time visual inspection is necessary to make 
such a determination.
    Operators should note that, although the service bulletin specifies 
that the manufacturer must be contacted for disposition of certain 
conditions, this proposal would require the repair of those conditions 
to be accomplished in accordance with a method approved by the Manager, 
Los Angeles Aircraft Certification Office (ACO), FAA, Transport 
Airplane Directorate.

Cost Impact

    There are approximately 93 McDonnell Douglas Model DC-9-10, -15, 
and -30 series airplanes, and C-9 (military) airplanes, of the affected 
design in the worldwide fleet. The FAA estimates that 80 airplanes of 
U.S. registry would be affected by this proposed AD, that it would take 
approximately 1 work hour per airplane to accomplish the proposed one-
time visual inspection, and that the average labor rate is $60 per work 
hour. Based on these figures, the cost impact of the one-time visual 
inspection proposed by this AD on U.S. operators is estimated to be 
$4,800, or $60 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.
    Should an operator be required to accomplish the necessary x-ray 
inspection, it would take approximately 1 work hour per airplane to 
accomplish, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact of any necessary x-ray inspection action 
is estimated to be $60 per airplane, per inspection cycle.
    Should an operator be required to accomplish the necessary eddy 
current inspection, it would take approximately 1 work hour per 
airplane to accomplish, at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of any necessary eddy current 
inspection action is estimated to be $60 per airplane, per inspection 
cycle.
    Should an operator be required to accomplish the necessary 
modification, it would take approximately 14 work hours per airplane to 
accomplish, at an average labor rate of $60 per work hour. The cost of 
required parts could range from $714 per airplane to as much as $1,526 
per airplane. Based on these figures, the cost impact of any necessary 
modification action is estimated to be between $1,554 and $2,366 per 
airplane.

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 96-NM-272-AD.

    Applicability: Model DC-9-10, -15, and -30 series airplanes, and 
C-9 (military) airplanes; as listed in McDonnell Douglas Service 
Bulletin DC9-53-276, dated September 30, 1996; 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 (d) 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 detect and correct fatigue cracking in the fuselage skin or 
doubler at the corners of the upper cargo doorjamb, which could 
result in rapid decompression of the fuselage and consequent reduced 
structural integrity of the airplane, accomplish the following:


[[Page 8646]]


    Note 2: Where there are differences between the service bulletin 
and the AD, the AD prevails.
    Note 3: The words ``repair'' and ``modify/modification'' in this 
AD and the referenced service bulletin are used interchangeably.
    Note 4: This AD will affect Principal Structural Element (PSE) 
53.09.023 of the DC-9 Supplemental Inspection Document (SID).

    (a) Prior to the accumulation of 41,000 total landings, or 
within 3,000 landings after the effective date of this AD, whichever 
occurs later, perform a one-time visual inspection to determine if 
the corners of the upper cargo doorjamb have been modified prior to 
the effective date of this AD.
    (b) If the visual inspection required by paragraph (a) of this 
AD reveals that the corners of the upper cargo doorjamb have not 
been modified, prior to further flight, perform an x-ray inspection 
to detect cracks of the fuselage skin and doubler at all corners of 
the upper cargo doorjamb, in accordance with McDonnell Douglas 
Service Bulletin DC9-53-276, dated September 30, 1996.
    (1) If no crack is detected during the x-ray inspection required 
by this paragraph, accomplish the requirements of either paragraph 
(b)(1)(i) or (b)(1)(ii) of this AD, in accordance with McDonnell 
Douglas Service Bulletin DC9-53-276, dated September 30, 1996.
    (i) Option 1. Repeat the x-ray inspection required by paragraph 
(b) of this AD thereafter at intervals not to exceed 3,000 landings; 
or
    (ii) Option 2. Prior to further flight, modify the corner skin 
of the upper cargo doorjamb, in accordance with the service 
bulletin. Prior to the accumulation of 28,000 landings after 
accomplishment of the modification, perform an eddy current 
inspection to detect cracks on the skin adjacent to the 
modification, in accordance with the service bulletin.
    (A) If no crack is detected on the skin adjacent to the 
modification during the eddy current inspection required by this 
paragraph, repeat the eddy current inspection thereafter at 
intervals not to exceed 20,000 landings.
    (B) If any crack is detected on the skin adjacent to the 
modification during any eddy current inspection required by this 
paragraph, prior to further flight, repair it in accordance with a 
method approved by the Manager, Los Angeles Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate.
    (2) If any crack is found during any x-ray inspection required 
by this paragraph and the crack is 2 inches or less in length: Prior 
to further flight, modify/repair it in accordance with the service 
bulletin. Prior to the accumulation of 28,000 landings after 
accomplishment of the modification, perform an eddy current 
inspection to detect cracks on the skin adjacent to the 
modification, in accordance with the service bulletin.
    (i) If no crack is detected during the eddy current inspection 
required by this paragraph, repeat the eddy current inspection 
thereafter at intervals not to exceed 20,000 landings.
    (ii) If any crack is detected during any eddy current inspection 
required by this paragraph, prior to further flight, repair it in 
accordance with a method approved by the Manager, Los Angeles ACO.
    (3) If any crack is found during any x-ray inspection required 
by this paragraph and the crack is greater than 2 inches in length: 
Prior to further flight, modification it in accordance with a method 
approved by the Manager, Los Angeles ACO.
    (c) If the visual inspection required by paragraph (a) of this 
AD reveals that the corners of the upper cargo doorjamb have been 
modified previously: Prior to the accumulation of 28,000 landings 
after accomplishment of that modification, or within 3,000 landings 
after the effective date of this AD, whichever occurs later, perform 
an eddy current inspection to detect cracks on the skin adjacent to 
the modification, in accordance with McDonnell Douglas Service 
Bulletin DC9-53-276, dated September 30, 1996.
    (1) If no crack is detected during the eddy current inspection 
required by this paragraph, repeat the eddy current inspection 
thereafter at intervals not to exceed 20,000 landings.
    (2) If any crack is detected during any eddy current inspection 
required by this paragraph, prior to further flight, repair it in 
accordance with a method approved by the Manager, Los Angeles ACO.
    (d) 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 5: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (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.

    Issued in Renton, Washington, on February 20, 1997.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-4714 Filed 2-25-97; 8:45 am]
BILLING CODE 4910-13-U