[Federal Register Volume 64, Number 66 (Wednesday, April 7, 1999)]
[Rules and Regulations]
[Pages 16805-16808]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-8329]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-110-AD; Amendment 39-11110; AD 99-08-05]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain McDonnell Douglas Model DC-9 and C-9 (military) 
series airplanes. This amendment requires repetitive inspections to 
detect fatigue cracking of the fuselage frames and longerons 16R and 
17R above the forward lower cargo door; repair, if necessary; and 
modification of the fuselage frames and longerons, if necessary, and 
follow-on repetitive inspections to detect fatigue cracking of the skin 
adjacent to the modification. This amendment is prompted by numerous 
instances of fatigue cracking of the fuselage frames and longerons. The 
actions specified by this AD are intended to prevent fatigue cracking 
of the fuselage frames and longerons 16R and 17R, which could result in 
reduced structural integrity of the airplane.

DATES: Effective May 12, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 12, 1999.

ADDRESSES: The service information referenced in this AD may be 
obtained from The Boeing Commercial Aircraft Group, 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 Federal Aviation 
Administration (FAA), Transport Airplane Directorate, Rules Docket, 
1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Transport 
Airplane Directorate, Los

[[Page 16806]]

Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC.

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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain McDonnell Douglas Model 
DC-9 and C-9 (military) series airplanes was published in the Federal 
Register on April 27, 1998 (63 FR 20548). That action proposed to 
require repetitive inspections to detect fatigue cracking of the 
fuselage frames and longerons 16R and 17R above the forward lower cargo 
door; repair, if necessary; and modification of the fuselage frames and 
longerons, if necessary, and follow-on repetitive inspections to detect 
fatigue cracking of the skin adjacent to the modification.

Comments

    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 indicates that it is not affected by the proposed 
rule.

Request To Extend Compliance Time

    One commenter requests that the FAA extend the proposed compliance 
time for the initial inspection from 30,000 total landings, or within 
3,000 landings after the effective date of this AD (whichever occurs 
later), to 30,000 total landings, or within 3,500 landings after the 
effective date of this AD (whichever occurs later). The commenter 
indicates that the 3,000-landing time limit will cause scheduling 
problems and will adversely affect operators. The commenter also states 
that an additional 500 landings would assure a smooth transition into 
the operators' maintenance program and would not cause additional 
safety concerns.
    The FAA does not concur with the commenter's request. In developing 
an appropriate compliance time for the initial inspection, the FAA 
considered not only the degree of urgency associated with addressing 
the fatigue cracking of the fuselage frames and longerons, but other 
factors as well. Those factors include the recommendations of the 
manufacturer, and the practical aspect of accomplishing the initial 
inspection within an interval of time coinciding with normal scheduled 
maintenance for the majority of the affected operators. In that regard, 
the commenter did not provide any data to substantiate that an 
extension of the compliance time would not compromise safety. In view 
of those factors, and the amount of time that has already elapsed since 
issuance of the notice of proposed rulemaking, the FAA has determined 
that further delay of this inspection is, in general, not appropriate. 
The FAA may, however, approve a request for an adjustment of the 
compliance time under the provisions of paragraph (e) of this final 
rule if data are submitted to substantiate that such an adjustment 
would provide an equivalent level of safety.

Request To Extend/Eliminate Repetitive Inspection Interval for 
Modified Airplanes

    One commenter requests that the proposed repetitive inspection 
interval for modified airplanes be extended or eliminated. The 
commenter states that incorporation of the modification of the fuselage 
frames and longerons 16R and 17R above the forward cargo door, in 
accordance with McDonnell Douglas Service Bulletin DC9-53-267, dated 
October 20, 1997, will improve the fatigue design of the longeron-to-
frame attach points, thereby decreasing the probability of frame and 
longeron cracking that could result in secondary damage to the fuselage 
skin. The commenter also states that accomplishing the preventative 
modification should allow the repetitive inspection interval to be 
increased or should eliminate the need for repetitive inspections.
    The FAA does not concur with the commenter's request. The FAA has 
coordinated this issue with the manufacturer and has determined that 
the repetitive inspections for modified airplanes are necessary to 
ensure an adequate level of safety for the transport airplane fleet. 
The cracking of the fuselage skin adjacent to the modification above 
the forward lower cargo door is fatigue-related, and the 19,000-landing 
repetitive inspection intervals were calculated based on fatigue and 
damage tolerance analysis. Therefore, no change to the final rule is 
necessary in this regard.

Request Credit for Previously Accomplished Work

    Two commenters request credit for prior accomplishment of the 
proposed initial inspection. The commenters state that documented 
inspections were accomplished previously in accordance with AD 94-03-
01, amendment 39-8807 (59 FR 6538, February 11, 1994), or AD 96-13-03, 
amendment 39-9671 (61 FR 31009, June 19, 1996), per supplemental 
inspection document (SID) Report No. L26-008, Section 02, Volume II, 
Chapter 53-10-01, dated November 1987, using the same inspection method 
cited in the proposed AD, and in accordance with McDonnell Douglas 
Service Bulletin DC9-53-267, which was cited as the appropriate source 
of service information for accomplishment of the initial inspection.
    The FAA concurs with the commenters' requests that an initial 
inspection accomplished prior to the effective date of this AD in 
accordance with AD 94-03-01 or AD 96-13-03 is acceptable for compliance 
with the initial inspection requirement in the final rule. However, the 
FAA notes that operators are always given credit for work accomplished 
previously if the work is performed in accordance with the existing AD 
by means of the phrase in the compliance section of the AD that states, 
``Required as indicated, unless accomplished previously.'' Therefore, 
no change to the final rule is necessary in this regard.

Request To Revise Paragraph (b)(1) of the Proposed Rule

    One commenter requests that paragraph (b)(1) of the proposed rule 
be revised to read, ``Option 1. Repeat the visual inspections in 
accordance with McDonnell Douglas Service Bulletin DC9-53-267, dated 
October 20, 1997, Paragraph 3.B. (SID Report No. L26-008, Volume II, 
Chapter 53-10-08, dated July 1997).'' The commenter states that 
paragraph (b)(1) of the proposal is unclear because the service 
bulletin does not specify the inspection procedure for the repetitive 
inspections.
    The FAA concurs that clarification should be provided. The intent 
of paragraph (b)(1) is that operators repeat the visual inspection 
required by paragraph (a) of the AD. That paragraph requires 
accomplishment of the visual inspection specified in paragraph 3.B.1. 
of the Accomplishment Instructions of the service bulletin referenced 
by the commenter. Additionally, paragraph 3.B.1. of the service 
bulletin points to the SID report identified by the commenter. For 
clarification purposes, the FAA has revised paragraph (a) of the final 
rule to reference paragraph 3.B.1. of the service bulletin. In 
addition, the FAA has revised paragraph (b)(1) of the final rule to 
specify that the visual

[[Page 16807]]

inspection to be repeated is that required by paragraph (a) of this AD.

Request To Revise Paragraphs (b)(2) and (c) of the Proposed Rule

    This same commenter requests that paragraphs (b)(2) and (c) of the 
proposed rule be revised to define the inspection area and give 
operators the option to inspect the fuselage skin either internally or 
externally. The commenter interprets the repetitive inspection 
requirements of these paragraphs as being limited to the fuselage skin 
only, as shown in the shaded area in SID Report No. L26-008, Volume II, 
Chapter 53-10-08, dated July 1997, which does not include the longerons 
or frames.
    The FAA concurs that clarification should be provided. The visual 
inspection specified in paragraphs (b)(2) and (c) of this AD is 
required to be accomplished in accordance with the inspection procedure 
specified in McDonnell Douglas Service Bulletin DC9-53-267, dated 
October 20, 1997. The intent of that inspection is to detect fatigue 
cracking of the fuselage skin adjacent to the modification. The only 
method for such inspection is an internal visual inspection of the 
inboard side of the fuselage, as specified in SID Report No. L26-008, 
Volume II, Chapter 53-10-08, dated July 1997 (which is referenced in 
the service bulletin as the appropriate inspection procedure for 
accomplishment of the visual inspection). Any crack will initiate at 
the frames and longerons, and the repair area cannot be seen from the 
outside. Therefore, the inspection must be accomplished internally to 
detect cracking of the skin adjacent to the repair.
    For clarification purposes, the FAA has revised paragraph (b)(2) of 
the final rule to reference paragraph 3.B.1.D. of the Accomplishment 
Instructions of the service bulletin. Paragraph (c) of the final rule 
also has been revised to reference paragraph 3.B.1.D.(5) of the 
Accomplishment Instructions of the service bulletin. [Paragraphs 
3.B.1.D. and 3.B.1.D.(5) reference the SID specified above for 
accomplishment of the visual inspection.]

Request To Allow Operator Approval of Certain Repairs

    The same commenter requests that the FAA revise paragraphs 
(b)(2)(ii) and (c)(2) of the proposed AD to permit repairs of any 
cracked structure found on subsequent inspections to be accomplished by 
the operators in accordance with FAA-approved data, rather than in 
accordance data approved by the Manager of the Los Angeles Aircraft 
Certification Office (ACO), FAA, Transport Airplane Directorate. The 
commenter states that the findings and repair methods could be 
submitted to the Los Angeles ACO for subsequent review.
    The FAA does not concur with the commenter's request. Access to the 
type design data is needed for repair data approval, and operators do 
not have such access. Therefore, the FAA has determined that to 
maintain an acceptable level of safety for the affected fleet, repair 
or modification of any cracked structure referenced in paragraphs 
(b)(2)(ii) and (c)(2) of this AD must be approved by the Manager, Los 
Angeles ACO. No change to the final rule is necessary in this regard.

Explanation of Changes to Final Rule

    Paragraph (d) of the final rule has been revised to provide 
clarification. The revised paragraph states that accomplishment of the 
inspection requirements of this AD constitutes terminating action for 
inspections of Principal Structural Element 53.09.055A (defined in 
McDonnell Douglas Report No. L26-008, DC-9 Supplemental Inspection 
Document, Report No. L26-008, Section 2 of Volume III-95, dated 
September 1995). As a result of this revision, the FAA also has removed 
NOTE 2 of the proposal; this note is no longer necessary.

Conclusion

    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 with the changes described 
previously. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    There are approximately 887 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 582 airplanes of U.S. registry 
will be affected by this AD. It will take approximately 1 work hour per 
airplane to accomplish the required inspection, at an average labor 
rate of $60 per work hour. Based on this figure, the cost impact of the 
inspection required by this AD on U.S. operators is estimated to be 
$34,920, 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 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 modification, it 
would take approximately 4 work hours per airplane to accomplish, at an 
average labor rate of $60 per work hour. Required parts would cost 
approximately $860 or $713 per airplane, depending on the service kit 
purchased. Based on these figures, the cost impact of the modification 
is estimated to be as high as $1,100 and as low as $953 per airplane.
    Should an operator be required to accomplish the follow-on 
inspection of the fuselage skin, it would take approximately 1 work 
hour per airplane to accomplish the inspection, at an average labor 
rate of $60 per work hour. Based on this figure, the cost impact of the 
follow-on inspection on U.S. operators is estimated to be $60 per 
airplane, per inspection cycle.

Regulatory Impact

    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 part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

[[Page 16808]]

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:

99-08-05  McDonnell Douglas: Amendment 39-11110. Docket 98-NM-110-
AD.

    Applicability: Model DC-9 and C-9 (military) series airplanes, 
as listed in McDonnell Douglas Service Bulletin DC9-53-267, dated 
October 20, 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 (e) 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 prevent fatigue cracking of the fuselage frames and longerons 
16R and 17R, which could result in reduced structural integrity of 
the airplane, accomplish the following:
    (a) Prior to the accumulation of 30,000 total landings, or 
within 3,000 landings after the effective date of this AD, whichever 
occurs later, perform a visual inspection to detect fatigue cracking 
of the fuselage frames and longerons 16R and 17R above the forward 
lower cargo door, in accordance with paragraph 3.B.1. of the 
Accomplishment Instructions of McDonnell Douglas Service Bulletin 
DC9-53-267, dated October 20, 1997.
    (b) Condition 1. If no cracking is detected during the 
inspection required by paragraph (a) of this AD, accomplish the 
requirements of either paragraph (b)(1) or (b)(2) of this AD, in 
accordance with McDonnell Douglas Service Bulletin DC9-53-267, dated 
October 20, 1997.
    (1) Option 1. Repeat the visual inspection required by paragraph 
(a) of this AD thereafter at intervals not to exceed 19,000 
landings. Or
    (2) Option 2. Prior to further flight, modify the fuselage 
frames and longerons 16R and 17R. Prior to the accumulation of 
19,000 landings after accomplishment of the modification, perform 
the visual inspection specified in paragraph 3.B.1.D. of the 
Accomplishment Instructions of the service bulletin to detect 
fatigue cracking of the skin adjacent to the modification.
    (i) If no cracking is detected, repeat the visual inspection 
thereafter at intervals not to exceed 19,000 landings.
    (ii) If any cracking is detected, prior to further flight, 
repair in accordance with a method approved by the Manager, Los 
Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane 
Directorate.
    (c) Condition 2. If any cracking is detected during the 
inspection required by paragraph (a) of this AD, prior to further 
flight, repair the cracked area and modify the fuselage frames and 
longerons 16R and 17R; in accordance with McDonnell Douglas Service 
Bulletin DC9-53-267, dated October 20, 1997. Prior to the 
accumulation of 19,000 landings after accomplishment of the 
modification, perform the visual inspection specified in paragraph 
3.B.1.D.(5) of the Accomplishment Instructions of the service 
bulletin to detect fatigue cracking of the skin adjacent to the 
modification, in accordance with the service bulletin.
    (1) If no cracking is detected, repeat the visual inspection 
thereafter at intervals not to exceed 19,000 landings.
    (2) If any cracking is detected, prior to further flight, repair 
in accordance with a method approved by the Manager, Los Angeles 
ACO.
    (d) Accomplishment of the inspections required by this AD 
constitutes terminating action for the inspections of Principal 
Structural Element 53.09.055A (reference McDonnell Douglas Model DC-
9 Supplemental Inspection Document, Report No. L26-008, Section 2 of 
Volume III-95, dated September 1995), as required by AD 96-13-03, 
amendment 39-9671.
    (e) 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (f) 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.
    (g) Except as provided by paragraphs (b)(2)(ii) and (c)(2) of 
this AD, the actions shall be done in accordance with McDonnell 
Douglas Service Bulletin DC9-53-267, dated October 20, 1997. 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 Boeing Commercial Aircraft Group, 
Douglas Products Division, 3855 Lakewood Boulevard, Long Beach, 
California 90846, Attention: Technical Publications Business 
Administration, Dept. C1-L51 (2-60). 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, 3960 Paramount Boulevard, 
Lakewood, California; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC.
    (h) This amendment becomes effective on May 12, 1999.

    Issued in Renton, Washington, on March 30, 1999.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-8329 Filed 4-6-99; 8:45 am]
BILLING CODE 4910-13-U