[Federal Register Volume 64, Number 26 (Tuesday, February 9, 1999)]
[Proposed Rules]
[Pages 6259-6261]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-3034]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-340-AD]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model MD-90-30 Series 
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 
MD-90-30 series airplanes. This proposal would require a one-time 
inspection to measure clearance and detect interference between the 
elevator cable pulley and the shroud frame of the ventral stairway, and 
modification of the shroud frame of the ventral stairway. This proposal 
is prompted by reports of pitch oscillation of several Model MD-90-30 
series airplanes. The actions specified by the proposed AD are intended 
to prevent interference between the elevator cable pulley and the 
shroud frame of the ventral stairway, which could result in pitch 
oscillation of the airplane, and consequent damage to the elevator 
cable pulley and reduced controllability of the airplane.

DATES: Comments must be received by March 26, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-340-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 Boeing Commercial Airplane Group, Long Beach 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: Jon Mowery, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los 
Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California 90712-4137; telephone (562) 627-5322; 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

[[Page 6260]]

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-340-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-340-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports indicating that pitch oscillation has 
occurred on several McDonnell Douglas Model MD-90-30 series airplanes. 
Investigation revealed that insufficient clearance exists between the 
elevator cable pulley and the shroud frame of the ventral stairway. 
Interference between the elevator cable pulley and the shroud frame of 
the ventral stairway restricts transmission of elevator servo inputs to 
the elevator. Such interference, if not corrected, could result in 
pitch oscillation of the airplane, and consequent damage to the 
elevator cable pulley and reduced controllability of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved McDonnell Douglas Service 
Bulletin No. MD90-27-026, dated September 30, 1998, which describes 
procedures for a one-time visual inspection to measure clearance and 
detect interference between the elevator cable pulley and the shroud 
frame of the ventral stairway. The service bulletin also describes 
procedures for modification of the shroud frame of the ventral 
stairway. The modification involves installation of a brace that 
attaches to the shroud frame of the ventral stairway and the outboard 
ring frame of the ventral stairway. This modification is intended to 
stabilize the shroud frame of the ventral stairway and prevent it from 
rotating toward the elevator cable pulley. Accomplishment of the 
actions specified in the service bulletin is intended to adequately 
address the identified unsafe condition.

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 accomplishment of the actions specified in 
the service bulletin described previously, except as discussed below.

Differences Between the Proposed Rule and the Service Bulletin

    Operators should note that, although the service bulletin 
recommends accomplishment of the modification of the shroud frame of 
the ventral stairway at the operator's earliest practical maintenance 
period if the clearance is within the specified limits and no 
interference is detected, the FAA has determined that such an 
interpretive compliance time would not address the identified unsafe 
condition in a timely manner. In developing an appropriate compliance 
time for this proposed AD, the FAA considered not only the 
manufacturer's recommendation, but the degree of urgency associated 
with addressing the subject unsafe condition, the average utilization 
of the affected fleet, the accessibility of the area to be modified, 
and the time necessary to accomplish the modification (approximately 
two work hours). In light of all of these factors, the FAA finds an 18-
month compliance time for completion of the proposed modification to be 
warranted, in that it represents an appropriate interval of time 
allowable for affected airplanes to continue to operate without 
compromising safety.

Cost Impact

    There are approximately 58 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 58 airplanes of U.S. registry 
would be affected by this proposed AD.
    It would take approximately 1 work hour per airplane to accomplish 
the proposed inspection, at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of the inspection proposed by 
this AD on U.S. operators is estimated to be $3,480, or $60 per 
airplane.
    It would take approximately 2 work hours per airplane to accomplish 
the proposed modification, at an average labor rate of $60 per work 
hour. Required parts would be provided by the manufacturer at no cost 
to the operators. Based on these figures, the cost impact of the 
modification proposed by this AD on U.S. operators is estimated to be 
$6,960, or $120 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.

[[Page 6261]]

Sec. 39.13  [Amended]

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

McDonnell Douglas: Docket 98-NM-340-AD.

    Applicability: Model MD-90-30 series airplanes, as listed in 
McDonnell Douglas Service Bulletin No. MD90-27-026, dated September 
30, 1998; 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 interference between the elevator cable pulley and 
the shroud frame of the ventral stairway, which could result in 
pitch oscillation of the airplane, and consequent damage to the 
elevator cable pulley and reduced controllability of the airplane, 
accomplish the following:
    (a) Within 12 months after the effective date of this AD, 
perform a one-time visual inspection to measure clearance and detect 
interference between the elevator cable pulley and the shroud frame 
of the ventral stairway in accordance with Phase 1 of McDonnell 
Douglas Service Bulletin No. MD90-27-026, dated September 30, 1998.
    (1) If clearance is greater than or equal to 0.5 inch, and if no 
interference is detected: Within 18 months after performing the 
inspection, accomplish the requirements of paragraph (b) of this AD.
    (2) If clearance is less than 0.5 inch, or if any interference 
is detected: Prior to further flight, accomplish the requirements of 
paragraph (b) of this AD.
    (b) Modify the shroud frame of the ventral stairway in 
accordance with Phase 2 of McDonnell Douglas Service Bulletin No. 
MD90-27-026, dated September 30, 1998.
    (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 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.

    (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.

    Issued in Renton, Washington, on February 2, 1999.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-3034 Filed 2-8-99; 8:45 am]
BILLING CODE 4910-13-U