[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
