[Federal Register Volume 63, Number 75 (Monday, April 20, 1998)]
[Proposed Rules]
[Pages 19423-19425]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-10277]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-06-AD]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-9-10, -20, -
30, -40, and -50 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, -20, -30, -40, and -50 series airplanes, and C-9 (military) 
airplanes. This proposal would require a one-time visual inspection to 
determine if the doorstops and corners of the doorjamb of the forward 
passenger door have been 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 and doorstops of the doorjamb of the forward passenger 
door. 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 June 4, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-06-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 The Boeing Company, Douglas Products Division, 3855 
Lakewood Boulevard, Long Beach, California 90846, Attention: Technical 
Publications Business Administration, Dept. 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, Transport Airplane Directorate, Los 
Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California 90712-4137; 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 98-NM-06-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-114, Attention: Rules 
Docket No. 98-NM-06-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 and doorstops of the doorjamb of the forward 
passenger door on Model DC-9 series airplanes. These cracks were 
discovered during inspections conducted as part of the Supplemental 
Inspection Document (SID) 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 doublers at the corners and doorstops of the doorjamb 
of the forward passenger door, if not detected and corrected, 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 DC9-53-280, dated December 1, 1997. The service bulletin 
describes the following procedures:
    1. Performing a one-time visual inspection to determine if the 
doorstops and corners of the forward passenger door doorjamb have been 
modified;
    2. For certain airplanes: Performing a low frequency eddy current 
(LFEC) or x-ray inspection to detect cracks at all corners and 
doorstops of the doorjamb of the forward passenger door;
    3. For certain other airplanes: Performing a high frequency eddy 
current (HFEC) inspection to detect cracks on the skin adjacent to the 
modification;
    4. Conducting repetitive inspections, or modifying the doorstops 
and corners of the doorjamb of the forward passenger door, and 
performing follow-on HFEC inspections, if no cracking is detected;

[[Page 19424]]

    5. Performing repetitive HFEC inspections to detect cracks on the 
skin adjacent to any doorstop or corner that has been modified; and
    6. Modifying any crack that is found to be 0.5 inches or less in 
length at all doorstops and corners that have not been modified, and 
performing follow-on repetitive HFEC inspections.
    Accomplishment of the modification will minimize the possibility of 
fatigue 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 
the doorstops and corners of the doorjamb of the forward passenger door 
have been modified, 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.

Difference Between the Service Bulletin and This Proposed AD

    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 1,001 airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 656 airplanes of U.S. 
registry would be affected by this proposed AD, and that it would take 
approximately 1 work hour per airplane to accomplish the proposed 
visual inspection, at an average labor rate of $60 per work hour. Based 
on these figures, the cost impact of the visual inspection proposed by 
this AD on U.S. operators is estimated to be $39,360 or $60 per 
airplane.
    Should an operator be required to accomplish the proposed 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 proposed by this AD on U.S. operators is estimated to be $60 
per airplane, per inspection cycle.
    Should an operator be required to accomplish the proposed 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 
proposed by this AD on U.S. operators is estimated to be $60 per 
airplane, per inspection cycle.
    Should an operator be required to accomplish the proposed 
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 between $490 and $1,775 per airplane, 
depending on the service kit purchased. Based on these figures, the 
cost impact of the modification proposed by this AD on U.S. operators 
is estimated to be between $2,290 and $3,575 per airplane.
    The cost impact figures discussed above are 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.

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 98-NM-06-AD.

    Applicability: Model DC-9-10, -20, -30, -40, and -50 series 
airplanes, and C-9 (military) airplanes, as listed in McDonnell 
Douglas Service Bulletin DC9-53-280, dated December 1, 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 doorstops and 
corners of the doorjamb of the forward passenger door, 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 is related to AD 96-13-03, amendment 39-9671, 
(61 FR 31009, June 19, 1996), and will affect Principal Structural 
Element (PSE) 53.09.031 of the DC-9 Supplemental Inspection Document 
(SID).

    (a) Prior to the accumulation of 48,000 total landings, or 
within 3,575 landings after the effective date of this AD, whichever 
occurs later, perform a one-time visual inspection to determine if 
the doorstops and corners of the forward passenger door doorjamb 
have been modified. Perform the inspection in accordance with 
McDonnell Douglas Service Bulletin DC9-53-280, dated December 1, 
1997.
    (b) For airplanes identified as Group 1 in McDonnell Douglas 
Service Bulletin DC9-53-280, dated December 1, 1997: If the visual 
inspection required by paragraph (a) of this AD reveals that the 
doorstops and corners of the forward passenger door doorjamb have

[[Page 19425]]

not been modified, prior to further flight, perform a low frequency 
eddy current (LFEC) or x-ray inspection to detect cracks at all 
corners and doorstops of the forward passenger door doorjamb, in 
accordance with McDonnell Douglas Service Bulletin DC9-53-280, dated 
December 1, 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 3,575 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 doorstops and 
corners of the forward passenger door 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 any HFEC inspection required by paragraph 
(b)(1)(ii) of this AD, 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 paragraph 
(b)(1)(ii) of this AD, 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 0.50 inch or less in length: Prior to further flight, 
modify the doorstops and corners of the forward passenger door 
doorjamb 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 on the skin adjacent to the 
modification during any HFEC inspection required by paragraph (b)(2) 
of this AD, 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 paragraph (b)(2) 
of this AD, 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 0.5 inch 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 DC-9-53-280, dated December 1, 
1997: If the visual inspection required by paragraph (a) of this AD 
reveals that the doorstops and corners of the forward passenger door 
doorjamb have been modified previously in accordance with the 
McDonnell Douglas DC-9 Structural Repair Manual (SRM), using a steel 
doubler, accomplish either paragraph (c)(1) or (c)(2) of this AD in 
accordance with McDonnell Douglas Service Bulletin DC-9-53-280, 
dated December 1, 1997.
    (1) Option 1. Prior to the accumulation of 28,000 landings after 
accomplishment of the modification, or within 3,000 landings after 
the effective date of this AD, whichever occurs later, 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 on the skin adjacent to the 
modification during any HFEC inspection required by paragraph (c)(1) 
of this AD, 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 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 doorstops and 
corners of the forward passenger door doorjamb in accordance with 
the service bulletin. Prior to the accumulation of 28,000 landings 
after the 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 on the skin adjacent to the 
modification during any HFEC inspection required by paragraph (c)(2) 
of this AD, 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 paragraph (c)(2) 
of this AD, prior to further flight, repair it in accordance with a 
method approved by the Manager, Los Angeles ACO.
    (d) Group 2, Condition 2. For airplanes identified as Group 2 in 
McDonnell Douglas Service Bulletin DC9-53-280, dated December 1, 
1997: If the visual inspection required by paragraph (a) of this AD 
reveals that the doorstops and corners of the forward passenger door 
doorjamb have been modified previously in accordance with McDonnell 
Douglas DC-9 SRM or Service Rework Drawing, using an aluminum 
doubler, prior to the accumulation of 28,000 landings after the 
accomplishment of the modification, or within 3,000 landings after 
the effective date of this AD, whichever occurs later, perform a 
HFEC inspection to detect cracks on the skin adjacent to the 
modification, in accordance with McDonnell Douglas Service Bulletin 
DC9-53-280, dated December 1, 1997
    (1) If no crack is detected on the skin adjacent to the 
modification during any HFEC inspection required by paragraph (d) of 
this AD, 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 paragraph (d) of 
this AD, prior to further flight, repair it in accordance with a 
method approved by the Manager, Los Angeles ACO.
    (e) Group 2, Condition 3. For airplanes identified as Group 2 in 
McDonnell Douglas Service Bulletin DC9-53-280, dated December 1, 
1997: If the visual inspection required by paragraph (a) of this AD 
reveals that the doorstops and corners of the forward passenger door 
doorjamb have been modified previously, but not in accordance with 
McDonnell Douglas DC9 SRM or the Service Rework Drawing, prior to 
further flight, repair it 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 April 13, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-10277 Filed 4-17-98; 8:45 am]
BILLING CODE 4910-13-U