[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
