# Airworthiness Directives; McDonnell Douglas Model DC-9 Series Airplanes and C-9 (Military) Airplanes

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URL: https://www.frixlaw.com/law-library/documents/fr%3A94-1584

## Record

- **Collection:** Federal Register
- **Document type:** Uncategorized Document
- **Published:** February 11, 1994

## Text

DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-NM-08-AD; Amendment 39-8807; AD 94-03-01]

Airworthiness Directives; McDonnell Douglas Model DC-9 Series
Airplanes and C-9 (Military) Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to McDonnell Douglas Model DC-9 series airplanes and
C-9 (military) airplanes, that currently requires the implementation of
a program of structural inspections to detect and correct fatigue
cracking in order to ensure the continued airworthiness of these
airplanes as they approach the manufacturer's original fatigue design
life goal. This amendment requires, among other things, revision of the
existing program to require visual inspections of additional structure.
This amendment is prompted by new data submitted by the manufacturer
indicating that certain revisions to the program are necessary in order
to increase the confidence level of the statistical program to ensure
timely detection of cracks in various airplane structures. The actions
specified by this AD are intended to prevent fatigue cracking that
could compromise the structural integrity of these airplanes.

DATES: Effective on March 14, 1994.
The incorporation by reference of certain publications listed in
the regulations was approved previously by the Director of the Federal
Register as of November 21, 1988 (53 FR 46866).
The incorporation by reference of certain other publications listed
in the regulations was approved by the Director of the Federal Register
as of March 14, 1994.

ADDRESSES: The service information referenced in this AD may be
obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach,
California 90846-1771, Attention: Business Unit Manager, Technical
Publications--Technical Administrative Support, C1-L5B. This
information may be examined at the Federal Aviation Administration
(FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue,
SW., Renton, Washington; or at the FAA, Transport Airplane Directorate,
Los Angeles Aircraft Certification Office, 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 Hsu, Aerospace Engineer,
Airframe Branch, ANM-122L, FAA, Transport Airplane Directorate, Los
Angeles Aircraft Certification Office, 3229 East Spring Street, Long
Beach, California 90806-2425; telephone (310) 988-5323; fax (310) 988-
5210.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations by superseding AD 87-14-07 R1, Amendment 39-6019
(53 FR 46866, November 21, 1988), which is applicable to McDonnell
Douglas Model DC-9 series airplanes and C-9 (military) airplanes, was
published in the Federal Register on March 29, 1993 (58 FR 16505). The
action proposed to require, among other things, revision of the
existing Structural Inspection Document (SID) sampling program to
require additional visual inspections of all Principal Structural
Elements (PSE) on certain airplanes.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
One commenter supports the proposal.
Several commenters objected to the proposed repair requirements
which would require that any cracked structure detected during the
required inspections be repaired ``in accordance with a method approved
by the Manager of the Los Angeles Aircraft Certification Office
(LAACO).'' These commenters prefer the language of AD 87-14-07 R1,
which permitted cracked structure to be repaired ``in accordance with
an FAA-approved method,'' and request that the rule be revised to
include this language. This requested language would allow repairs to
be approved routinely by the manufacturer, Designated Engineering
Representatives (DER), or SFAR 36-authorized organizations, without
prior approval by the Manager of LAACO. The commenters' justification
for this request involves three points:
1. The commenters contend that it is not logical that the manner of
repair approval should differ between repairs of PSE's found cracked
during a SID inspection and repairs of PSE's found cracked during
inspections other than those directly called for by the SID program.
2. The commenters also contend that it should not be necessary to
involve the Manager of the LAACO in the repair approval process, since
the process takes too much time. The commenters consider that adequate
repair procedures already are available in the DC-9 Structural Repair
Manual (SRM) and the service bulletins referenced in the SID; repair
procedures can also be designed and approved by DER's without further
review and approval of the LAACO.
3. Several of the commenters also request that the airplane
manufacturer, operator DER's, and SFAR 36-authorized operators be
allowed to approve repairs that are outside the scope of the SRM, at
least temporarily, in order to allow the airplane to be returned to
revenue service pending the outcome of a subsequent damage tolerance
assessment (DTA) of the repair, which is required by the SID program of
all repairs. These commenters state that restricting approval of such
repairs to the LAACO Manager would hamper repair efforts and ``would
have an appreciable effect on the airplane's return-to-service times.''
The FAA does not concur with the commenters' requests. While it is
true that DER's and SFAR 36-authorized organizations are authorized to
approve certain repairs of cracking that is found during routine
maintenance or opportunity inspections, the FAA considers that any
cracking detected in PSE structure during an inspection required by
this AD (and the SID program) is indication of an airworthiness concern
of a complex nature. Such cracking does not warrant ``routine''
handling, but requires expeditious action and a special approach to
address it. It is crucial that the FAA be aware of all repairs made to
PSE's or to their configuration. Where repair data do not exist, it is
essential that the FAA have feedback as to the type of repairs being
made. Given that possible new relevant issues might be revealed during
this process, it is imperative that the FAA have such feedback. Only by
reviewing repair approvals can the FAA be assured of this feedback and
of the adequacy of the repair methods. The FAA has determined that
standardization and continuity of repair approvals can best be
maintained by having one single point of approval for all repairs of
cracks in PSE's identified during SID inspections required by this AD.
Since the Manager of the LAACO is accountable for the primary oversight
for the actions regarding this AD, it is appropriate that he be this
single point of approval. His involvement, therefore, is warranted in
the development and approval of repairs.
Standardization and continuity of repair approval is especially
important in light of the complexity of the DC-9 SID program. This
program is unique in that it is based on the principle of statistical
sampling, which requires cooperation between aircraft operators, the
manufacturer, and the FAA in selecting airplane samples, accomplishing
inspections, reporting discrepancies as they are found, and evaluating
the safety impact of the discrepancies so that timely program
adjustments can be made and the appropriate corrective actions taken to
protect both the discrepant airplane and the fleet. For example, when
one bona fide fatigue crack is determined, the inspection and repair
requirements must be developed in a timely manner to protect the entire
Model DC-9 fleet. This requires coordination with the Manager of the
LAACO for the review of all SID findings and a timely determination of
bona fide fatigue cracking.
Further, cracked PSE structure detected during an inspection that
is not directly required by the SID must first be reported to the FAA
by the operator via a Service Difficulty Report (SDR), as is required
by the relevant operating rules of the Federal Aviation Regulations.
These SDR reports are compiled in an SDR data base that is used by the
FAA for trend analysis and data studies used in planning, directing,
controlling, and evaluating various airworthiness programs. Cracked PSE
structure found during an inspection called out by the SID program (and
this AD) are compiled into a SID data base that is used by the FAA for
many of the same purposes as SDR data base, including identification of
necessary revisions to the SID program itself. The Manager of the LAACO
has access to both the SDR and the SID data bases and, therefore, he is
in a unique position that affords him a broad overview both to
understand and assess the overall cracking and repair environment, and
to implement timely initiatives to address and manage it.
As part of the SID program, every repair of PSE structure is
required to have a DTA in order to establish its effect on the fatigue
life of the affected PSE structure. The DTA process involves the review
and use of type design data that are proprietary and may not be
available to those persons (such as a DER) who are generally authorized
to approve routine repairs. For this reason, it is appropriate that the
Manager of the LAACO be the focal point in the DTA approval process.
In some cases, repairs are made to PSE structure as a result of
cracking that was found during an opportunity inspection, and the
approval of the repair is made without the coordination of the
manufacturer and the LAACO. When the time arrives for that PSE to be
inspected in compliance with the AD, the PSE becomes a ``discrepant
PSE.'' If a DTA were not accomplished on the ``discrepant PSE'' at the
time of the repair, compliance with the AD could require that the
repair be removed or modified at a later time. In either case, the
Manager of the LAACO is asked to ensure that all repairs to cracked
PSE's comply with the AD.
The FAA considers that any repair to cracked PSE's without the
required DTA can only be temporary, and will eventually require
coordination with the Manager of the LAACO. Most methods of repair
specified in the DC-9 Structural Repair Manual, the relevant service
bulletins, or DER-designed repairs do not include a continuing
inspection program to ensure that the repair is inspected at the same
level of safety as the original PSE structure. A DTA can be done most
easily at the time of repair, rather than at a later date when the
details of the repair may be hard to obtain and, undoubtedly, would be
more costly. Currently, the Manager and staff of the LAACO are working
very closely with the manufacturer to expedite interim repair approval
requests. Such requests may be made under the provisions of paragraph
(d) of the final rule.
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule as proposed.
There are approximately 920 Model DC-9 series airplanes and C-9
(military) airplanes of the affected design in the worldwide fleet. The
FAA estimates that 586 airplanes of U.S. registry and 19 U.S. operators
would be affected by this proposed AD.
Incorporation of the SID program into an operator's maintenance
program, as was required by AD 87-14-07 R1, necessitates approximately
1,000 work hours (per operator), at an average labor cost of $55 per
work hour. Based on these figures, the cost to the 19 affected U.S.
operators to incorporate the SID program, which was required previously
in accordance with AD 87-14-07 R1, is estimated to be $1,045,000.
The incorporation of the additional procedures that are required by
this new AD action will require approximately 62 additional work hours
per operator to accomplish, at an average labor cost of $55 per work
hour. Based on these figures, the cost to the 19 affected U.S.
operators to incorporate these additional procedures into the SID
program into an operator's maintenance program is estimated to be
$64,790.
The recurring inspection costs, as was required by AD 87-14-07 R1
and continues to be required by this new AD action, is approximately
341 work hours per airplane per year, at an average labor cost of $55
per work hour. Based on these figures, these recurring inspection costs
are estimated to be $18,755 per airplane, or $10,990,430 for the
affected U.S. fleet.
The recurring inspection procedures that are added to the program
by this new AD action will require approximately 21 additional work
hours per airplane per year to accomplish, at an average labor charge
of $55 per work hour. Based on these figures, the additional recurring
inspection cost impact added by this AD on U.S. operators is estimated
to be $1,155 per airplane, or $676,830 for the affected U.S. fleet.
Based on the figures discussed above, the total cost impact of this
AD is estimated to be $11,732,050 for the first year, and $11,667,260
for each year thereafter. These ``total cost impact'' figures assume
that no operator has yet accomplished any of the requirements of this
AD. However, it can be reasonably assumed that a majority of affected
operators have already initiated the original SID program (as required
by AD 87-14-07 R1) and many may have already initiated the additional
inspections required by this new AD action.
Additionally, the number of required work hours for each inspection
requirement of this AD (and the SID program), as indicated above, is
presented as if the accomplishment of those actions were to be
conducted as ``stand alone'' actions. However, in actual practice,
these actions for the most part will be accomplished coincidentally or
in combination with normally scheduled airplane inspections and other
maintenance program tasks. Therefore, the actual number of necessary
additional work hours will be minimal in many instances. Further, any
costs associated with special airplane scheduling can be expected to be
minimal.
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.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it 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 removing amendment 39-6019 (53 FR
46866, November 21, 1988), and by adding a new airworthiness directive
(AD), amendment 39-8807, to read as follows:

94-03-01 McDonnell Douglas: Amendment 39-8807. Docket 93-NM-08-AD.
Supersedes AD 87-14-07 R1, Amendment 39-6019.

Applicability: Model DC-9-10, -20, -30, -40, -50 series
airplanes, and C-9 (Military) airplanes; certificated in any
category.
Compliance: Required as indicated, unless accomplished
previously.
To ensure the continuing structural integrity of these
airplanes, accomplish the following:
(a) Within one year after December 23, 1988 (the effective date
of AD 87-14-07 R1, Amendment 39-6019), incorporate a revision into
the FAA-approved maintenance inspection program which provides for
inspection(s) of the Principal Structural Elements (PSE) defined in
McDonnell Douglas Report No. L26-008, ``DC-9 Supplemental Inspection
Document (SID),'' Section 2 of Volume I (All Series) of Revision 1,
dated November 1987, in accordance with Section 2 of Volume III-87,
dated November 1987, of the SID. The non-destructive inspection
(NDI) techniques set forth in Section 2 of Volume II, dated November
1987, of the SID provide acceptable methods for accomplishing the
inspections required by this paragraph. All inspection results
(negative or positive) must be reported to McDonnell Douglas, in
accordance with the instructions contained in Section 2 of Volume
III-87, dated November 1987, of the SID. Information collection
requirements contained in this regulation have been approved by the
Office of Management and Budget (OMB) under the provisions of the
Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have
been assigned OMB Control Number 2120-0056.

Note 1: Volume II, dated November 1987, of the SID is comprised
of the following:

------------------------------------------------------------------------
Revision
Volume designation- level shown
on volume
------------------------------------------------------------------------
Volume II-10/20-......................................... Original.-
Volume II-20/30-......................................... 1.
Volume II-40-............................................ Original.-
Volume II-50-............................................ Original.
------------------------------------------------------------------------

-(b) Within 6 months after the effective date of this AD,
replace the revision of the FAA-approved maintenance inspection
program required by paragraph (a) of this AD, with a revision that
provides for inspection(s) of the PSE's defined in McDonnell Douglas
Report No. L26-008, ``DC-9 Supplemental Inspection Document (SID),''
Section 2 of Volume I of Revision 3, dated April 1991, in accordance
with Section 2 of Volume III-92, dated July 1992, of the SID.
(1) Visual inspections of all PSE's on airplanes listed in
Volume III-92, dated July 1992, of the SID planning data, are
required by the fleet leader-operator sampling (FLOS) program at
least once during the interval between the start date (SDATE) and
the end date (EDATE) established for each PSE. These visual
inspections are defined in Section 3 of Volume II, dated April 1991,
of the SID, and are required only for those airplanes that have not
been inspected previously in accordance with Section 2 of Volume II,
dated April 1991, of the SID.
(2) The NDI techniques set forth in Section 2 of Volume II,
dated April 1991, of the SID provide acceptable methods for
accomplishing the inspections required by this paragraph.
(3) All inspection results (negative or positive) must be
reported to McDonnell Douglas, in accordance with the instructions
contained in section 2 of Volume III-92, dated July 1992, of the
SID. Information collection requirements contained in this
regulation have been approved by the OMB under the provisions of the
Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have
been assigned OMB Control Number 2120-0056.

Note 2: Volume II, dated April 1991, of the SID is comprised of
the following:

------------------------------------------------------------------------
Revision
Volume Designation- level shown
on volume
------------------------------------------------------------------------
Volume II-10/20............................................ 3
Volume II-20/30............................................ 4
Volume II-40............................................... 3
Volume II-50............................................... 3
------------------------------------------------------------------------

Note 3: NDI inspections accomplished in accordance with the
following Volume II of the SID provide acceptable methods for
accomplishing the inspections required by this paragraph:

------------------------------------------------------------------------
Revision Date of
Volume Designation-- level-- revision
------------------------------------------------------------------------
Volume II-10/20-- -....................... 3---......... April 1991.
Volume II-10/20-- -....................... 2---......... April 1990.
Volume II-10/20---........................ 1---......... June 1989.
Volume II-10/20--......................... Original- -.. November
1987.
Volume II-20/30---........................ 4---......... April 1991.
Volume II-20/30---........................ 3---......... April 1990.
Volume II-20/30---........................ 2---......... June 1989.
Volume II-20/30---........................ 1---......... November
1987.
Volume II-40---........................... 3---......... April 1991.
Volume II-40---........................... 2---......... April 1990.
Volume II-40--............................ 1---......... June 1989.
Volume II-40---........................... Original-.... November
1987.
Volume II-50---........................... 3---......... April 1991.
Volume II-50---........................... 2---......... April 1990.
Volume II-50---........................... 1---......... June 1989.
Volume II-50---........................... Original--... November
1987.
------------------------------------------------------------------------

(c) Any cracked structure detected during the inspections
required by paragraph (a) or (b) of this AD must be repaired before
further flight, in accordance with a method approved by the Manager,
Los Angeles Aircraft Certification Office (ACO), FAA, Transport
Airplane Directorate.

-Note 4: Requests for approval of any PSE repair that would
affect the FAA-approved maintenance inspection program that is
required by this AD should include a damage tolerance assessment for
that PSE.

-(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 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
FAR 21.197 and 21.199 to operate the airplane to a location where
the requirements of this AD can be accomplished.
(f) Certain of the inspections to be added to the FAA-approved
maintenance program shall be done in accordance with McDonnell
Douglas Report No. L26-008, ``DC-9 Supplemental Inspection Document
(SID),'' dated November 1987. The incorporation by reference of this
document was approved previously by the Director of the Federal
Register, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51, as
of December 23, 1988 (53 FR 46866, November 21, 1988). Certain other
of the inspections to be added to the FAA-approved maintenance
program shall be done in accordance with the following volumes of
McDonnell Douglas Report No. L26-008, ``DC-9 Supplemental Inspection
Document (SID),'' that contain the lists of effective pages
indicated below:---------

--------------------------------------------------------------------------------------------------------------------------------------------------------
Revision
Document Page number level Date
--------------------------------------------------------------------------------------------------------------------------------------------------------
Volume I--All Series............. List of Effective Pages A, B, C.................................................... 3............ April 1991.
Volume II-10/20.................. List of Effective Pages A, B, C, D, E, F, G, H, I, J, K............................ 3............ April 1991.
L.................................................................................. 2............ April 1990.
Volume II-20/30.................. List of Effective Pages A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, U. 4............ April 1991.
T.................................................................................. Original..... April 1990.
Volume II-40..................... List of Effective Pages A, B, C, D, E, F, G, H, I, J, K, L, M, N, O................ 3............ April 1991.
Volume II-50..................... List of Effective Pages A, B, C, D, E, F, G, H, I, J, K, L, M, N, O................ 3............ April 1991.
Volume III-92 All Series......... Entire Document.................................................................... Original..... July 1992.
--------------------------------------------------------------------------------------------------------------------------------------------------------

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 90846-1771, Attention:
Business Unit Manager, Technical Publications--Technical
Administrative Support, C1-L5B. Copies may be inspected at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington; or at the FAA, Transport Airplane Directorate, Los
Angeles Aircraft Certification Office, 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 March 14, 1994.

Issued in Renton, Washington, on January 20, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-1584 Filed 2-10-94; 8:45 am]
BILLING CODE 4910-13-U

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A94-1584. Public record. Not legal advice.