[Federal Register Volume 63, Number 17 (Tuesday, January 27, 1998)]
[Proposed Rules]
[Pages 3852-3854]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-1858]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-NM-99-AD]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Model DC-9-31 Series
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-9-31 series airplanes.
This proposal would require a one-time visual inspection to
determine if all corners of the forward service door doorjamb have been
modified previously, 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 forward service door 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 March 13, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 97-NM-99-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; or at 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, Los Angeles Aircraft Certification
Office, 3960 Paramount Boulevard, Lakewood, California 90712; 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.
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-99-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. 97-NM-99-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 forward service door doorjamb on
Model DC-9-31 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 forward service door 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 DC9-53-288, dated February 10, 1997. The service bulletin
describes the following procedures:
1. Performing a one-time visual inspection to determine if the
corners of the forward service door doorjamb have been modified;
2. For airplanes on which the modification specified in Service
Bulletin DC9-53-288 has not been accomplished: Performing a low
frequency eddy current (LFEC) or x-ray inspection to detect cracks of
the fuselage skin and doubler at all corners of the forward service
door doorjamb;
3. Conducting repetitive inspections, or modifying the corner skin
of the doorjamb of the forward service door and performing follow-on
action high frequency eddy current (HFEC) inspections, if no cracking
is detected;
4. Performing repetitive HFEC inspections to detect cracks on the
skin adjacent to any corner that has been modified; and
5. 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 HFEC inspections.
Accomplishment of the modification will minimize the possibility of
cracks in the fuselage skin and doubler.
[[Page 3853]]
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 forward service door doorjamb have been modified
previously, various follow-on repetitive inspections, and modification,
if necessary. The one-time visual inspection, follow-on repetitive
inspections, and modification would be required to be accomplished in
accordance with the service bulletin described previously.
Differences Between the Proposed Rule and the Relevant Service
Information
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 FAA.
Cost Impact
There are approximately 64 McDonnell Douglas Model DC-9-31 series
airplanes of the affected design in the worldwide fleet. The FAA
estimates that 51 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 of the proposed AD on
U.S. operators is estimated to be $3,060, or $60 per airplane.
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 LFEC or 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 LFEC or x-ray
inspection is estimated to be $60 per airplane, per inspection cycle.
Should an operator be required to accomplish the HFEC 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 HFEC inspection is estimated to be $60 per
airplane, per inspection cycle.
Should an operator be required to accomplish the modification, it
would take approximately 30 work hours per airplane to accomplish, at
an average labor rate of $60 per work hour. Required parts would cost
approximately $4,800 per airplane. Based on these figures, the cost
impact of any necessary modification is estimated to be $6,600 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 97-NM-99-AD.
Applicability: Model DC-9-31 series airplanes, as listed in
McDonnell Douglas Service Bulletin DC9-53-288, dated February 10,
1997, 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 (f) 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 forward service door doorjamb, which
could result in rapid decompression of the fuselage and consequent
reduced structural integrity of the airplane, accomplish the
following:
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)
53.09.033 of the DC-9 Supplemental Inspection Document (SID).
(a) Prior to the accumulation of 50,000 total landings, or
within 3,225 landings after the effective date of this AD, whichever
occurs later, perform a one-time visual inspection to determine if
the corners of the forward service door doorjamb have been modified.
Perform the inspection in accordance with McDonnell Douglas Service
Bulletin DC9-53-288, dated February 10, 1997.
(b) For airplanes identified as Group 1 in McDonnell Douglas
Service Bulletin DC9-53-288, dated February 10, 1997: If the visual
inspection required by paragraph (a) of this AD reveals that the
corners of the forward service door doorjamb have not been modified,
prior to further flight, perform a low frequency eddy currrent
(LFEC) or x-ray inspection to detect cracks of the fuselage skin and
doubler at all corners of the forward service door doorjamb, in
accordance with McDonnell Douglas Service Bulletin DC9-53-288, dated
February 10, 1997.
(1) Group 1, Condition 1. If no crack is detected during any
LFEC or x-ray inspection required by paragraph (b) of this AD,
accomplish the requirements of either paragraph (b)(1)(i) or
(b)(1)(ii) of this AD, in accordance with the service bulletin.
(i) Option 1. Repeat the LFEC inspection required by this
paragraph thereafter at intervals not to exceed 3,225 landings, or
the x-ray inspection required by this paragraph thereafter at
intervals not to exceed 3,075 landings; or
(ii) Option 2. Prior to further flight, modify the corner skin
of the forward service door
[[Page 3854]]
doorjamb in accordance with the service bulletin. Prior to the
accumulation of 28,000 landings after accomplishment of the
modification, perform a high frequency eddy current (HFEC)
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 HFEC required by this paragraph, repeat the
HFEC 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 HFEC 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) Group 1, Condition 2. If any crack is found during any LFEC
or x-ray inspection required by paragraph (b) of this AD, and the
crack is 2 inches or less in length: Prior to further flight,
modify/repair the corners of the doorjamb of the forward service
door in accordance with the service bulletin. Prior to the
accumulation of 28,000 landings after accomplishment of the
modification, perform a HFEC 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 HFEC inspection required
by this paragraph, repeat the HFEC inspection thereafter at
intervals not to exceed 20,000 landings.
(ii) If any crack is detected during any HFEC inspection
required by this paragraph, prior to further flight, repair it in
accordance with a method approved by the Manager, Los Angeles ACO.
(3) Group 1, Condition 3. If any crack is found during any LFEC
or x-ray inspection required by paragraph (b) of this AD, and the
crack is greater than 2 inches in length: Prior to further flight,
repair it in accordance with a method approved by the Manager, Los
Angeles ACO.
(c) Group 2, Condition 1. For airplanes identified as Group 2 in
McDonnell Douglas Service Bulletin DC9-53-288, dated February 10,
1997: If the visual inspection required by paragraph (a) of this AD
reveals that the corners of the forward service door doorjamb have
been modified previously in accordance with the McDonnell Douglas
DC-9 Structural Repair Manual, using a steel doubler, accomplish
either paragraph (c)(1) or (c)(2) of this AD in accordance with
McDonnell Douglas Service Bulletin DC9-53-288, dated February 10,
1997.
(1) Option 1. Prior to the accumulation of 6,000 landings after
accomplishment of that modification, or within 3,225 landings after
the effective date of this AD, whichever occurs later, perform an
HFEC 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 HFEC inspection required
by paragraph (c)(1) of this AD, repeat the HFEC inspection
thereafter at intervals not to exceed 3,000 landings.
(ii) If any crack is detected during any HFEC inspection
required by paragraph (c)(1) of this AD, prior to further flight,
repair it in accordance with a method approved by the Manager, Los
Angeles ACO.
(2) Option 2. Prior to further flight, modify the corner skin of
the forward service door doorjamb in accordance with the service
bulletin. Prior to the accumulation of 28,000 landings after
accomplishment of the modification, perform an HFEC inspection to
detect cracks on the skin adjacent to the modification, in
accordance with the service bulletin.
(i) If no crack is detected on the skin adjacent to the
modification during the HFEC required by this paragraph, repeat the
HFEC inspection thereafter at intervals not to exceed 20,000
landings.
(ii) If any crack is detected on the skin adjacent to the
modification during any HFEC 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.
(d) Group 2, Condition 2. For airplanes identified as Group 2 in
McDonnell Douglas Service Bulletin DC9-53-288, dated February 10,
1997: If the visual inspection required by paragraph (a) of this AD
reveals that the corners of the forward service door doorjamb have
been modified previously in accordance with McDonnell Douglas DC-9
Structural Repair Manual, using an aluminum doubler, prior to the
accumulation of 28,000 landings after accomplishment of that
modification, or within 3,225 landings after the effective date of
this AD, whichever occurs later, perform an HFEC inspection to
detect cracks on the skin adjacent to the modification, in
accordance with McDonnell Douglas Service Bulletin DC9-53-288, dated
February 10, 1997.
(1) If no crack is detected on the skin adjacent to the
modification during the HFEC required by this paragraph, repeat the
HFEC inspection thereafter at intervals not to exceed 20,000
landings.
(2) If any crack is detected on the skin adjacent to the
modification during any HFEC 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.
(e) Group 2, Condition 3. For airplanes identified as Group 2 in
McDonnell Douglas Service Bulletin DC9-53-288, dated February 10,
1997: If the visual inspection required by paragraph (a) of this AD
reveals that the corners of the forward service door doorjamb have
been modified previously, but not in accordance with McDonnell
Douglas Structural Repair Manual, prior to further flight, repair
the corners in accordance with a method approved by the Manager, Los
Angeles ACO.
(f) 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.
(g) 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 January 20, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 98-1858 Filed 1-26-98; 8:45 am]
BILLING CODE 4910-13-U
