[Federal Register Volume 61, Number 96 (Thursday, May 16, 1996)]
[Rules and Regulations]
[Pages 24686-24688]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-12148]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-191-AD; Amendment 39-9623; AD 96-10-16]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas MD-11 Series Airplane

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 MD-11 series airplanes, 
that requires inspections to detect damage of the sidewall vent box 
diaphragms, and repair, if necessary. This amendment also requires the 
eventual installation of stops on the vent box diaphragm, which 
terminates the inspection requirements of the AD. This amendment is 
prompted by reports of damage to sidewall vent box diaphragms, which 
can result in non-functional diaphragms during a rapid decompression. 
The actions specified by this AD are intended to prevent buckling of 
the floor beams due to insufficient air flow of the cabin sidewall vent 
box diaphragms during rapid decompression, and consequent reduction in 
the controllability of the airplane.

DATES: Effective June 20, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 20, 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: Andrew Gfrerer, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130L, FAA, Los Angeles Aircraft 
Certification Office, 3960 Paramount Boulevard, Lakewood, California 
90712; telephone (310) 627-5338; 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 certain McDonnell Douglas Model MD-11 series airplanes 
was published in the Federal Register on February 21, 1996 (61 FR 
6581). That action proposed to require repetitive inspections to detect 
damage of the sidewall vent box assemblies. Initially, that action 
proposed to permit continued flight if only a certain number of 
assembleis are found to be damaged. However, once that number is 
exceeded, the damaged assemblies would be required to be modified, 
prior to further flight, until the remaining number of damaged 
assemblies does not exceed a certain number. That amendment also 
proposed to require the eventual installation of stop pads for all vent 
box diaphragms and reidentification of the assemblies,

[[Page 24687]]

which, when accomplished, terminates the requirement for the repetitive 
inspections.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the two comments received.
    Both commenters support the proposed rule.

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 as proposed.

Cost Impact

    There are approximately 123 Model MD-11 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 39 
airplanes of U.S. registry will be affected by this AD.
    To accomplish the required inspections will take approximately 2 
work hours per airplane, per inspection, at an average labor rate of 
$60 per work hour. Based on these figures, the cost impact of the 
required inspections on U.S. operators is estimated to be $4,680, or 
$120 per airplane, per inspection cycle.
    To accomplish the requried installation and reidentification will 
take a total of approximately 270 work hours per airplane. This figure 
represents 3 work hours per vent box, and up to a maximum of 90 vent 
boxes on an airplane. The average labor rate is $60 per work hour. The 
cost of requried parts will be negligible; the parts may be fabricated 
locally. Based on these figures, the cost impact of the required 
installation on U.S. operators is estimated to be $631,800, or $16,200 
per airplane.
    The cost impact figures 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.

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), 40113, 44701.


Sec. 39.13  [Amended]

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

96-10-16  McDonnell Douglas: Amendment 39-9623. Docket 95-NM-191-AD.

    Applicability: Model MD-11 series airplane, as listed in 
McDonnell Douglas Alert Service Bulletin MD11-25A181, dated 
September 28, 1995; 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 (c) 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 buckling of the floor beams due to insufficient air 
flow of the cabin sidewalk vent box diaphragms during rapid 
decompression, and subsequent loss of airplane control capabilities, 
accomplish the following:
    (a) Within 90 days after the effective date of this AD, perform 
an inspection to detect damage of the sidewalk vent box diaphragms, 
in accordance with McDonnell Douglas Alert Service Bulletin MD11-
25A181, dated September 28, 1995. Based on the findings of the 
initial inspection, or any repetitive inspection, accomplish the 
requirements of paragraph (a)(1), (a)(2), or (a)(3) of this AD, as 
applicable:
    (1) Condition 1. If no damage is detected: Repeat the inspection 
at intervals not to exceed 90 days.
    (2) Condition 2. If damage is detected, but the number of 
damaged sidewall vent box assemblies does not exceed the applicable 
allowable number specified in Table 1 of the alert service bulletin: 
Repeat the inspection at intervals not to exceed 90 days.
    (3) Condition 3. If damage is detected, and the number of 
damaged vent box assemblies exceeds the applicable number specified 
in Table 1 of the alert service bulletin: Prior to further flight, 
install stops on and re-identify as many damaged sidewall vent box 
assemblies as necessary so that the total number of damaged vent box 
assemblies does not exceed the applicable allowable number specified 
in Table 1 of the alert service bulletin. Accomplish the 
installation of the stops and reidentification of the assemblies in 
accordance with the alert service bulletin. The installation of 
stops on and reidentification of an assembly constitutes terminating 
action for the repetitive inspections of that assembly only. All 
other assemblies must continue to be inspected thereafter at 
intervals not to exceed 90 days.
    (b) Within 30 months after the effective date of this AD, 
install stops on and reidentify all sidewalk vent box assemblies 
that do not already have stops installed and have not been 
reidentified in accordance with McDonnell Douglas Alert Service 
Bulletin MD11-25A181, dated September 28, 1995. Accomplishment of 
this action constitutes terminating action for the inspection 
requirements of this AD.
    (c) 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), FAA, Transport Airplane Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspectors, 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.

    (d) 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.
    (e) The inspections and installations shall be done in 
accordance with McDonnell Douglas Alert Service Bulletin MD11-
25A181, dated September 28, 1995. This incorporation by reference 
was approved by

[[Page 24688]]

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.

    (f) This amendment becomes effective on June 20, 1996.

    Issued in Renton, Washington, on May 9, 1996.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-12148 Filed 5-15-96; 8:45 am]
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