[Federal Register Volume 59, Number 9 (Thursday, January 13, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-345]
[[Page Unknown]]
[Federal Register: January 13, 1994]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 93-NM-224-AD; Amendment 39-8790; AD 94-01-08]
Airworthiness Directives; McDonnell Douglas Model DC-9 and C-9
(Military) Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to certain McDonnell Douglas Model DC-9 and C-9
(military) series airplanes. This action requires inspections to detect
cracking in the ventral aft pressure bulkhead, and repair, if
necessary. This amendment is prompted by reports of cracking found in
the ventral aft pressure bulkhead on several airplanes. The actions
specified in this AD are intended to prevent the propagation of cracks
in the ventral aft pressure bulkhead, which could lead to failure of
the bulkhead and subsequent rapid decompression of the airplane.
DATES: Effective January 28, 1994.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of January 28, 1994.
Comments for inclusion in the Rules Docket must be received on or
before March 14, 1994.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 93-NM-224-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056.
The service information referenced in this AD may be obtained from
McDonnell Douglas Corporation, P. O. Box 1771, Long Beach, California
90846-0001, Attention: Business Unit Manager, Technical Publications,
C1-HDR (54-60). This information may be examined at the FAA, Transport
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at
the Los Angeles Aircraft Certification Office, FAA, Transport Airplane
Directorate, 3229 East Spring Street, Long Beach, California; or at the
Office of the Federal Register, 800 North Capitol Street NW., suite
700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: David Y. J. Hsu, Airframe Branch, ANM-
120L, Los Angeles Aircraft Certification Office, FAA, Transport
Airplane Directorate, 3229 East Spring Street, Long Beach, California
90806-2425; telephone (310) 988-5325; fax (310) 988-5210.
SUPPLEMENTARY INFORMATION: The FAA has recently received reports of
cracking found in the ventral aft pressure bulkhead on several
McDonnell Douglas Model DC-9 series airplanes. Two operators reported
finding fatigue cracks on four airplanes in both the left- and right-
hand side ventral aft pressure bulkhead web and doublers, between water
lines (stations) Z=43.000 and Z=74.000. The length of the reported
cracks found in the webs ranged from 5 inches to 48 inches. The webs of
each of the cracked bulkheads on the subject airplanes were made of
2014-T6 material and were 0.042 inch thick. It is suspected that
fatigue is the cause of the cracks. The affected airplanes had
accumulated between 73,803 and 83,760 landings at the time of the crack
findings. In each case, the cracking was found during inspections that
were outside of the operator's normal maintenance program schedule.
Currently, there is no requirement for regular inspection of the
affected area of the bulkhead. Cracking in the ventral aft pressure
bulkhead web or doublers, if allowed to propagate to a critical length,
could lead to failure of the bulkhead, extensive structural damage, and
subsequent rapid decompression of the airplane.
The FAA has reviewed and approved McDonnell Douglas DC-9 Alert
Service Bulletin A53-264, dated December 22, 1993, that describes
procedures for conducting repetitive visual, low frequency eddy
current, and high frequency eddy current inspections to detect cracking
in the ventral aft pressure bulkhead. The area of inspection includes
the upper left and right sides of the ventral aft pressure bulkhead in
the area of the finger doublers and web between stations Z=34.000 and
Z=74.000, from the edge of the ventral doorway outboard and upward
along the edge of the doublers. -
Since an unsafe condition has been identified that is likely to
exist or develop on other Model DC-9 and C-9 (military) series
airplanes of the same type design, this AD is being issued to prevent
failure of the ventral aft pressure bulkhead due to cracking. This AD
requires repetitive visual, low frequency eddy current, and high
frequency eddy current inspections to detect cracking in the ventral
aft pressure bulkhead. These inspections are required to be
accomplished in accordance with the service bulletin described
previously. Any cracks found are required to be repaired, prior to
further flight, in accordance with a method approved by the FAA.
Additionally, operators are required to submit a report of initial
inspection findings to the FAA.
This is considered to be interim action until final action is
identified, at which time the FAA may consider further rulemaking.
Since a situation exists that requires the immediate adoption of
this regulation, it is found that notice and opportunity for prior
public comment hereon are impracticable, and that good cause exists for
making this amendment effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves
requirements affecting flight safety and, thus, was not preceded by
notice and an opportunity for public comment, comments are invited on
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All
communications received on or before the closing date for comments will
be considered, and this rule may be amended in light of the comments
received. Factual information that supports the commenter's ideas and
suggestions is extremely helpful in evaluating the effectiveness of the
AD action and determining whether additional rulemaking action would be
needed. -
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the rule that might
suggest a need to modify the 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 that
summarizes each FAA-public contact concerned with the substance of this
AD 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 93-NM-224-AD.'' The postcard will be date stamped and
returned to the commenter. -
The regulations adopted herein will 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 final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
The FAA has determined that this regulation is an emergency
regulation that must be issued immediately to correct an unsafe
condition in aircraft, and is not a ``significant regulatory action''
under Executive Order 12866. It has been determined further that this
action involves an emergency regulation under DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979). If it is determined
that this emergency regulation otherwise would be significant under DOT
Regulatory Policies and Procedures, a final regulatory evaluation will
be prepared and placed in the Rules Docket. A copy of it, if filed, may
be obtained from the Rules Docket at the location provided under the
caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends 14 CFR part
39 of the Federal Aviation Regulations as follows:
PART 39--AIRWORTHINESS DIRECTIVES -
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended] -
2. Section 39.13 is amended by adding the following new
airworthiness directive:
94-01-08 McDonnell Douglas: Amendment 39-8790. Docket 93-NM-224-AD.
-Applicability: Model DC-9 and C-9 (military) series airplanes,
as listed in McDonnell Douglas DC-9 Alert Service Bulletin A53-264,
dated December 22, 1993; equipped with a ventral aft pressure
bulkhead web composed of 2014-T6 material that is 0.042 inch thick;
certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent failure of the aft pressure bulkhead due to cracking,
accomplish the following:
(a) For airplanes on which the procedures specified in McDonnell
Douglas DC-9 Service Bulletins 53-26 and A53-144, or production
equivalent, have not been accomplished (Group I airplanes): Upon the
accumulation of 50,000 total landings, or within 30 days after the
effective date of this AD, whichever occurs later, conduct an
initial visual, low frequency eddy current, and high frequency eddy
current inspection to detect cracks in the ventral aft pressure
bulkhead, in accordance with McDonnell Douglas DC-9 Alert Service
Bulletin A53-264, dated December 22, 1993.
(1) If no crack is detected during any of the inspections,
repeat these inspections at intervals not to exceed 1,500 landings.
-
(2) If any crack is detected during any of the inspections,
prior to further flight, repair in accordance with a method approved
by the Manager, Los Angeles Aircraft Certification Office (ACO),
FAA, Transport Airplane Directorate. -
(b) For airplanes on which the procedures specified in McDonnell
Douglas DC-9 Service Bulletins 53-26 and A53-144, or production
equivalent, have previously been accomplished (Group II airplanes):
Upon the accumulation of 60,000 total landings, or within 60 days
after the effective date of this AD, whichever occurs later, conduct
an initial visual, low frequency eddy current, and high frequency
eddy current inspection to detect cracks in the ventral aft pressure
bulkhead, in accordance with McDonnell Douglas DC-9 Alert Service
Bulletin A53-264, dated December 22, 1993.
(1) If no crack is detected during any of the inspections,
repeat these inspections at intervals not to exceed 1,500 landings.
-
(2) If any crack is detected during any of the inspections,
prior to further flight, repair in accordance with a method approved
by the Manager, Los Angeles ACO, FAA, Transport Airplane
Directorate.
(c) Within 10 calendar days after accomplishing the initial
inspection required by paragraph (a) or (b) of this AD, as
applicable, submit a report of inspection findings, both positive
and negative, to the Manager, Los Angles ACO, FAA, Transport
Airplane Directorate, 3229 East Spring Street, Long Beach,
California 90806-2425; fax (310) 988-5210. The report must include
the following information: -
(1) Factory serial number of the airplane;
(2) Total time and flight cycles on the airplane;
(3) A detailed description of the discrepancy finding;
(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, 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: 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 FAR
21.197 and 21.199 to operate the airplane to a location where the
requirements of this AD can be accomplished.
(f) The inspections shall be done in accordance with McDonnell
Douglas DC-9 Alert Service Bulletin A53-264, dated December 22,
1993. This incorporation by reference was approved by the Director
of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR
part 51. Copies may be obtained from McDonnell Douglas Corporation,
P. O. Box 1771, Long Beach, California 90846-0001, Attention:
Business Unit Manager, Technical Publications, C1-HDR (54-60).
Copies may be inspected at the FAA, Transport Airplane Directorate,
1601 Lind Avenue SW., Renton, Washington; or at the Los Angeles
Aircraft Certification Office, FAA, Transport Airplane Directorate,
3229 East Spring Street, Long Beach, California; or at the Office of
the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
(g) This amendment becomes effective on January 28, 1994.
Issued in Renton, Washington, on January 3, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-345 Filed 1-12-94; 8:45 am]
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