[Federal Register Volume 61, Number 18 (Friday, January 26, 1996)]
[Rules and Regulations]
[Pages 2403-2407]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-187]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-16-AD; Amendment 39-9481; AD 96-01-05]


Airworthiness Directives; McDonnell Douglas Model DC-9-10, -20, -
30, -40, and -50 Series Airplanes 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 all McDonnell Douglas Model DC-9 and C-9 (military) 
series airplanes, that requires replacement, inspection, and 
modification of the attach fittings of the main landing gear (MLG). 
This amendment is prompted by reports of severe structural damage and 
rupture of the integral fuel tank due to overload of the MLG caused by 
adverse landing conditions. The actions specified by this AD are 
intended to minimize the possibility of primary structural damage and 
rupture of the 

[[Page 2404]]
integral fuel tank due to overload of the MLG; these conditions could 
lead to fuel spillage and a resultant fire.

DATES: Effective February 26, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of February 26, 1996.

ADDRESSES: The service information referenced in this AD 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 Federal Aviation Administration (FAA), Transport 
Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, 
Washington; or at the FAA, Los Angeles Aircraft Certification Office, 
Transport Airplane Directorate, 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: David Y. J. Hsu, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los 
Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California 90712; telephone (310) 627-5323; fax (310) 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 all McDonnell Douglas Model DC-9 
and C-9 (military) series airplanes was published in the Federal 
Register on May 24, 1995 (60 FR 27449). That action proposed to require 
replacement, inspection, and modification of the attach fittings of the 
main landing gear (MLG).
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    Several commenters support the proposed rule.

Requests for Extension of the Compliance Time

    Several commenters request that the proposed compliance time of 12 
months be extended by as much as 12 additional months. Two commenters 
indicate that a parts availability problem was encountered when 
accomplishing one of the service bulletins cited in the proposed rule, 
McDonnell Douglas DC-9 Service Bulletin 57-148. One of these commenters 
indicates that the manufacturer requires a lead time in excess of 6 
months to provide required parts. Another commenter states that, in 
light of the proposed time frame for compliance with the proposal, the 
number of work hours specified in the AD is too low because operators 
would need to schedule special maintenance visits to modify their 
aircraft. Similarly, other commenters request an extended compliance 
time that would align with regularly scheduled maintenance visits, 
thereby reducing lost revenue service. One commenter contends that 
inspection of MLG attach fittings in accordance with Revision 5 of 
McDonnell Douglas DC-9 Service Bulletin 57-148 will provide an adequate 
level of safety until modification of those fittings is accomplished.
    In light of these considerations, the FAA concurs with the 
commenters' requests to extend the compliance time. The FAA finds that 
extending the compliance time by 12 additional months will not 
adversely affect safety significantly, and will allow operators to 
accomplish the requirements of this AD at a base during regularly 
scheduled maintenance where special equipment and trained maintenance 
personnel will be available if necessary. Accordingly, paragraphs (a) 
and (b) of the final rule have been revised to specify a compliance 
time of 24 months.

Request To Clarify the Applicability of the AD

    One commenter requests that the applicability of the proposal be 
revised to reference the specific series of Model DC-9 airplanes 
affected, rather than simply specifying that the proposed AD applies to 
``All Model DC-9 and C-9 (military) series airplanes.'' The commenter 
justifies its request by stating that McDonnell Douglas considers Model 
MD-80 airplanes to be ``Series 80 DC-9'' airplanes. Therefore, since 
the service bulletins cited in the proposed AD only apply to Model DC-9 
series 10 through 50 and C-9 (military) series airplanes, the commenter 
suggests that those airplanes specifically be identified in the 
applicability of the AD to avoid any confusion and misinterpretation on 
the part of operators. The FAA concurs with the commenter's request, 
and has revised the applicability of the final rule accordingly.

Request To Include Actions Already Required by Other AD's

    One commenter requests that the actions currently required by three 
existing AD's be included in the proposed rule. Those AD's are:
     AD 80-06-04 R1, amendment 39-4909 (49 FR 35617, September 
11, 1984);
     AD 84-26-01, amendment 39-4971 (50 FR 448, January 4, 
1985); and
     AD 90-18-03, amendment 39-6701 (55 FR 34704, August 24, 
1990).
    The commenter provides the following justification for this 
request:
    1. The three existing AD's address the same subject as that 
specified in the proposed AD.
    2. One of the existing AD's, AD 90-18-03, specifies a compliance 
time for accomplishment of McDonnell Douglas DC-9 Service Bulletin 57-
125 that is different from the compliance time specified in the 
proposal for accomplishment of the same action.
    3. McDonnell Douglas DC-9 Service Bulletin 57-148, which is cited 
in paragraph (b) of the proposed rule, also is listed in Table 2.3 of 
Report No. MDC K1572, ``DC-9/MD80 Aging Aircraft Service Action 
Requirements Document (SARD),'' Revision B, dated January 15, 1993 
(hereinafter referred to as the ``SARD''). The compliance time 
specified in Table 2.3 of the SARD for accomplishment of McDonnell 
Douglas DC-9 Service Bulletin 57-148 differs from that specified in 
paragraph (b) of this proposed rule for accomplishment of the same 
action. Therefore, if a new AD is issued to mandate accomplishment of 
Table 2.3 of the SARD, the compliance time specified in this proposed 
AD may conflict with the compliance time specified in the new AD that 
addresses the SARD.
    The FAA acknowledges that certain actions specified in earlier 
versions of the service bulletins addressed in this AD (McDonnell 
Douglas DC-9 Service Bulletins 57-125 and 57-148) are mandated 
currently in the three existing AD's cited by the commenter and that 
the compliance times between certain documents vary. However, the FAA 
does not concur with the commenter's request to include the 
requirements of those AD's in this final rule for several reasons:
    On November 4, 1994, the FAA issued a notice of proposed rulemaking 
(NPRM), Docket 94-NM-92-AD (59 FR 56011, November 11, 1994), which 
proposes to supersede AD 90-18-03. That NPRM proposes to require, in 
part, the accomplishment of certain inspections and structural 
modifications specified in Table 2.3 of the SARD. The FAA acknowledges 
that the SARD references the two service bulletins cited in this final 
rule (McDonnell Douglas DC-9 Service Bulletins 57-125 and 57-148). 
However, in the final rule for Docket 94-NM-92-AD, the FAA intends to 
exclude the actions specified 

[[Page 2405]]
in the two service bulletins from the requirements of that AD. 
Therefore, the actions described in those service bulletins would be 
required by this AD only at the times specified herein.
    Further, the FAA finds that the accomplishment of the requirements 
of this final rule will terminate the requirements of AD 80-06-04 R1 
and AD 84-26-01. The FAA has added a new paragraph (c) in the final 
rule to specify this information.

Requests To Limit the Applicability of the AD

    One commenter requests that only airplanes equipped with certain 
gear fitting installations be applicable to the proposed AD. The 
commenter indicates that replacement of the attach fittings, as 
described in McDonnell Douglas DC-9 Service Bulletin 57-125, is 
addressed in AD 90-18-03, and that there are various configurations of 
fitting installations for which installation of smaller (\7/8\-inch 
diameter) lower tension bolts is not required. The commenter also 
indicates that, since the intent of the proposed AD is to improve the 
breakaway feature of the MLG (which is affected by the diameter of the 
lower tension bolts), only airplanes equipped with certain gear 
fittings would be affected by the proposed AD.
    The same commenter states that airplanes equipped with fittings 
having large counterbore radii (7075-T73 fittings) that were installed 
with clearance fit NAS bolts should be excluded from the applicability 
of the proposal. The commenter indicates that it operates such 
airplanes and, at one time, this type of installation was permissible. 
The commenter explains that, although the complete intent of McDonnell 
Douglas DC-9 Service Bulletin 57-148 has not been accomplished, the 
portion of the service bulletin that has not been accomplished does not 
affect the breakaway function of the fitting.
    Additionally, one commenter states that the proposed AD should 
require only the installation of a reduced diameter lower tension bolt 
(7/8-inch) and bushing portion of McDonnell Douglas DC-9 Service 
Bulletin 57-148 at an accelerated rate. The commenter adds that 
operators of large fleets should be allowed to accomplish the remainder 
of the actions specified in the service bulletin (including the 
enlargement of the counterbore, the replacement of the lower flange 
attachments with interference fit fasteners, and glass bead shotpeening 
of the fitting) on schedule in accordance with the SARD, which is being 
addressed in the final rule for Docket 94-NM-92-AD. The commenter 
contends that the actions required by the proposed AD would impose a 
severe hardship on operators. The commenter adds that only the 
reduction in size of the lower tension bolt improves the breakaway 
function of the gear fitting, which is the immediate concern addressed 
in the proposed AD.
    The FAA does not concur with these commenters' requests. The FAA 
acknowledges that the key to breakaway capability of the MLG is the 
installation of smaller (7/8-inch) diameter tension bolts that attach 
the MLG fittings to the airframe. However, the FAA finds that 
accomplishment of the corrective actions necessary to address stress 
corrosion cracking of these fittings is equally as critical as 
incorporation of the breakaway feature. Therefore, the FAA has 
determined that the two objectives must be accomplished concurrently to 
address these safety issues in a timely manner. The FAA finds that 
accomplishment of the actions specified in both service bulletins cited 
in this AD (McDonnell Douglas DC-9 Service Bulletins 57-125 and 57-148) 
within 24 months after the effective date of this AD will adequately 
address these safety concerns.

Request To Clarify Shotpeening Requirements

    One commenter questions the effectiveness of on-wing, glass bead 
shotpeening of the MLG fittings, as described in McDonnell Douglas DC-9 
Service Bulletins 57-125 and 57-148. The commenter states that, in 
order to be effective, shotpeening must be controlled precisely to 
attain the required Almen Intensity. The commenter remarks that on-wing 
shotpeening of the gear fittings cannot be controlled to obtain the 
required Almen Intensity and fatigue life improvement. The commenter 
specifies that the use of glass particles in the landing gear area, 
which includes many moveable components, raises a serious issue of 
system contamination and premature failure of components (i.e., 
bearings, due to glass particle contamination). The commenter makes no 
specific request for a change to the final rule, and provides no 
engineering data to substantiate that the fatigue life improvement is 
reduced or that premature failure of components occurs due to system 
contamination from glass particles.
    The FAA finds that some clarification is necessary. Although the 
shotpeening process described in the service bulletins has been used in 
service for a substantial period of time, neither the FAA nor the 
airplane manufacturer have received any reports concerning system 
contamination or premature failure of components. Therefore, the FAA 
finds that no change to the final rule is necessary in this regard. 
However, the FAA would consider a request for approval of an 
alternative method of compliance, in accordance with the provisions of 
paragraph (d) of this AD, provided that adequate justification is 
presented to support such a request.

Request To Clarify Number of Necessary Work Hours

    One commenter states that the actual work hours and elapsed times 
required to accomplish the actions specified in McDonnell Douglas DC-9 
Service Bulletin 57-148 differ substantially from the figures reflected 
in the service bulletin. The commenter remarks that the actual work 
hours are approximately 400 more than the number specified in the 
service bulletin, and that the actual elapsed time is 100 hours more.
    The FAA infers from these remarks that the commenter requests that 
the FAA revise the economic impact information, below, to increase the 
number of work hours required for accomplishment of the actions 
specified in this AD. The FAA concurs with the commenter's request. The 
FAA has revised the number of work hours estimated for accomplishment 
of the inspection and modification specified as Phase 2 in McDonnell 
Douglas DC-9 Service Bulletin 57-148 from 36 to 436 work hours. 
Estimated hours for elapsed time are not reflected specifically in AD 
actions.
    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 previously 
described. The FAA has determined that these changes will neither 
significantly increase the economic burden on any operator nor increase 
the scope of the AD.

Economic Impact

    There are approximately 906 Model DC-9 and C-9 (military) series 
airplanes of the affected design in the worldwide fleet. The FAA 
estimates that 549 airplanes of U.S. registry will be affected by this 
AD.
    The FAA estimates that the replacement specified as Option 1 in 
McDonnell Douglas DC-9 Service Bulletin 57-125 has been accomplished on 
all 549 airplanes of U.S. registry that will be affected by this AD. 
(As discussed previously, accomplishment of Option 1 was required by AD 
90-18-03.) Accordingly, the FAA finds that the replacement required by 
this AD will 

[[Page 2406]]
impose no additional economic burden on any U.S. operator.
    However, should an affected airplane be imported and placed on the 
U.S. Register in the future, it will require approximately 425 work 
hours to accomplish Option 1, at an average labor rate of $60 per work 
hour. The cost of required parts will be $58,853 per airplane. Based on 
these figures, the cost impact for accomplishing Option 1 will be 
$84,353 per airplane.
    The FAA estimates that all 549 airplanes of U.S. registry will be 
required to accomplish the inspection and modification specified as 
Phase 2 in McDonnell Douglas DC-9 Service Bulletin 57-148. It will take 
approximately 436 work hours per airplane to accomplish Phase 2, at an 
average labor rate of $60 per work hour. Required parts will cost 
approximately $4,338 per airplane. Based on these figures, the cost 
impact on U.S. operators for accomplishing Phase 2 is estimated to be 
$16,743,402, or $30,498 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished the requirement (Phase 2) of this AD 
action, and that no operator would accomplish that action in the future 
if this AD were not adopted.

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:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 USC 106(g), 40101, 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

96-01-05  McDonnell Douglas: Amendment 39-9481. Docket 95-NM-16-AD.

    Applicability: All Model DC-9-10, -20, -30, -40, and -50 series 
airplanes, and C-9 (military) series airplanes; certificated in any 
category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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 use the authority 
provided in paragraph (d) of this AD to request approval from the 
FAA. This approval may address either no action, if the current 
configuration eliminates the unsafe condition; or different actions 
necessary to address the unsafe condition described in this AD. Such 
a request should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.
    Compliance: Required as indicated, unless accomplished 
previously.
    To minimize the possibility of primary structural damage and 
rupture of the integral fuel tank due to overload of the main 
landing gear (MLG) caused by adverse landing conditions, and 
subsequent fuel spillage and a resultant fire, accomplish the 
following:
    (a) For airplanes on which Option 1 (or production equivalent) 
has not been accomplished as specified in McDonnell Douglas DC-9 
Service Bulletin 57-125 (original issue through Revision 5): Within 
24 months after the effective date of this AD, replace the attach 
fittings of both the right and left MLG's in accordance with Option 
1 of the Accomplishment Instructions of McDonnell Douglas DC-9 
Service Bulletin 57-125, Revision 5, dated November 5, 1990.

    Note 2: Airplanes on which Option 1 has been accomplished as 
specified in any of the following revisions of McDonnell Douglas DC-
9 Service Bulletin 57-125, are considered to be in compliance with 
this AD and no further action is required by this AD:

------------------------------------------------------------------------
 Service                                                                
bulletin          Revision level                       Date             
   No.                                                                  
------------------------------------------------------------------------
57-125..  Revision 3....................  October 28, 1982; or          
          Revision 4....................  June 21, 1983; or             
          Revision 5....................  November 5, 1990.             
------------------------------------------------------------------------

    (b) For airplanes on which Option 1 has been accomplished as 
specified in McDonnell Douglas DC-9 Service Bulletin 57-125 
(original version through Revision 2); but on which Phase 2 has not 
been accomplished as specified in McDonnell Douglas DC-9 Service 
Bulletin 57-148 (original version through Revision 5): Within 24 
months after the effective date of this AD, inspect and modify the 
attach fittings of both the right and left MLG's in accordance with 
Phase 2 of McDonnell Douglas DC-9 Service Bulletin 57-148, Revision 
5, dated November 23, 1992.

    Note 3: Airplanes on which both Option 1 (or a production 
equivalent) has been accomplished as specified in any of the 
following revisions of McDonnell Douglas DC-9 Service Bulletin 57-
125; and Phase 2 (or a production equivalent) has been accomplished 
as specified in any of the following revisions of McDonnell Douglas 
DC-9 Service Bulletin 57-148; are considered to be in compliance 
with this AD and no further action is required by this AD:

------------------------------------------------------------------------
 Service                                                                
bulletin          Revision level                       Date             
   No.                                                                  
------------------------------------------------------------------------
57-125     (Original)...................  January 26, 1979; or          
          Revision 1....................  February 16, 1979; or         
          Revision 2....................  August 24, 1979; and          
57-148    (Original)....................  October 1, 1982; or           
          Revision 1....................  June 8, 1983; or              
          Revision 2....................  August 9, 1989; or            
          Revision 3....................  September 11, 1990; or        
          Revision 4....................  February 25, 1991; or         
          Revision 5....................  November 23, 1992.            
------------------------------------------------------------------------

    (c) Accomplishment of the actions required by this AD 
constitutes terminating action for the requirements of AD 80-06-04 
R1, amendment 39-4909, and AD 84-26-01, amendment 39-4971.
    (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 Aircraft Certification 
Office (ACO), 

[[Page 2407]]
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 4: 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 
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.
    (f) The actions shall be done in accordance with McDonnell 
Douglas DC-9 Service Bulletin 57-125, Revision 5, dated November 5, 
1990; and McDonnell Douglas DC-9 Service Bulletin 57-148, Revision 
5, dated November 23, 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, 3855 Lakewood Boulevard, Long Beach, 
California 90846, Attention: Technical Publications Business 
Administration, Department C1-L51 (2-60). Copies may be inspected at 
the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., 
Renton, Washington; or at the FAA, Los Angeles Aircraft 
Certification Office, Transport Airplane Directorate, 3960 Paramount 
Boulevard, Lakewood, California; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
    (g) This amendment becomes effective on February 26, 1996.
    Issued in Renton, Washington, on January 2, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-187 Filed 1-25-96; 8:45 am]
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