[Federal Register Volume 62, Number 19 (Wednesday, January 29, 1997)]
[Proposed Rules]
[Pages 4217-4218]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-2215]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-SW-30-AD]
Airworthiness Directives; McDonnell Douglas Helicopter Systems
Model MD-900 Series Helicopters
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 McDonnell Douglas Helicopter
Systems (MDHS) Model MD-900 series helicopters. This proposal would
require removing certain serial-numbered main rotor swashplate bearings
(bearings) and replacing them with airworthy bearings. This proposal is
prompted by reports that inspections of several helicopters revealed
that the outer bearing race had been rotating relative to the
swashplate assembly, which was evidenced by wear marks in the rotating
swashplate. The actions specified by the proposed AD are intended to
prevent possible heat accumulation and resulting damage to the bearing
caused by the bearing races rotating relative to the bearing seat,
which could result in degraded helicopter response to pilot control
input and possible loss of control of the helicopter.
DATES: Comments must be received by March 31, 1997.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Assistant Chief Counsel, Attention:
Rules Docket No. 96-SW-30-AD, 2601 Meacham Blvd., Room 663, Fort Worth,
Texas 76137. Comments may be inspected at this location between 9:00
a.m. and 3:00 p.m., Monday through Friday, except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Mr. Greg DiLibero, Aerospace Engineer,
FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Blvd.,
Lakewood, California 90712, telephone (310) 627-5231, fax (310) 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 should identify the Rules Docket number
and be submitted in triplicate to the address specified above. All
communications received on or before the closing date 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 No. 96-SW-30-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, Office of the Assistant Chief Counsel, Attention: Rules
Docket No. 96-SW-30-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas
76137.
Discussion
This document proposes the adoption of a new AD that is applicable
to MDHS Model MD-900 series helicopters. This proposal would require,
before further flight, inspecting the bearing, part number (P/N)
900C3010100-101, to determine if a bearing having a serial number (S/N)
of S/N 059150-E0019, S/N 059150-E0020, S/N 059150-E0021, S/N 059150-
E0022, S/N 059150-E0023, S/N 059150-E0024, S/N 059150-E0025, S/N
059150-E0026, S/N 059150-E0027, S/N 059150-E0028, S/N 059150-E0029, or
S/N 059150-E0030 is installed, and if so, removing and replacing the
bearing with an airworthy bearing. This proposal is prompted by reports
of inspections of several helicopters that indicated the outer bearing
race had been rotating relative to the swashplate assembly, which was
evidenced by wear marks in the rotating swashplate. An investigation
revealed that 12 non-conforming bearings had been released to
production. Some of the 12 bearings have been located. The actions
specified by the proposed AD are intended to prevent possible heat
accumulation and resulting damage to the bearing caused by the bearing
races rotating relative to the bearing seat, which could result in
degraded helicopter response to pilot control input and possible loss
of control of the helicopter.
Since an unsafe condition has been identified that is likely to
exist or develop on other MDHS Model MD-900 series helicopters of the
same type design, the proposed AD would require, before further flight,
inspecting the bearing, P/N 900C3010100-101, to determine if a bearing
having S/N
[[Page 4218]]
059150-E0019, S/N 059150-E0020, S/N 059150-E0021, S/N 059150-E0022, S/N
059150-E0023, S/N 059150-E0024, S/N 059150-E0025, S/N 059150-E0026, S/N
059150-E0027, S/N059150-E0028, S/N 059150-E0029, or S/N 059150-E0030 is
installed; and, if installed, removing and replacing that bearing with
an airworthy bearing.
The FAA estimates that 20 helicopters of U.S. registry would be
affected by this proposed AD, that it would take approximately 1.5 work
hours per helicopter to determine the bearing's S/N, 12 work hours per
helicopter to remove and replace a bearing, if necessary, and that the
average labor rate is $60 per work hour. Replacement bearings would
cost $8,765 per helicopter, however, replacement bearings are covered
by a manufacturer's warranty. Based on these figures, the total cost
impact of the proposed AD on U.S. operators is estimated to be $5,400,
assuming five helicopters will require removal and replacement of the
bearing.
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 USC 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive
to read as follows:
McDonnell Douglas Helicopter Systems: Docket No. 96-SW-30-AD.
Applicability: Model MD-900 series helicopters, certificated in
any category.
Note 1: This AD applies to each helicopter 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 helicopters 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 (h) 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 helicopter from the applicability of this AD.
Compliance: Required before further flight, unless accomplished
previously.
To prevent possible heat accumulation and resulting damage to
the main rotor swashplate bearing (bearing) caused by the bearing
races rotating relative to the bearing seat, which could result in
degraded helicopter response to pilot control input and possible
loss of control of the helicopter, accomplish the following:
(a) Disconnect the lower end of the main rotor pitch links.
Disconnecting the drive link may make the inspection easier.
(b) Cut the safety wire and remove the inner and outer labyrinth
seals, part number (P/N) 900C2010194-101 and P/N 900C201190-101,
respectively, and the inner and outer bearing retaining rings.
(c) Inspect the bearing, part number (P/N) 900C3010100-101, to
determine if it has one of the following serial numbers (S/N): S/N
059150-E0019, S/N 059150-E0020, S/N 059150-E0021, S/N 059150-E0022,
S/N 059150-E0023, S/N 059150-E0024, S/N 059150-E0025, S/N 059150-
E0026, S/N 059150-E0027, S/N 059150-E0028, S/N 059150-E0029, or S/N
059150-E0030.
Note 2: S/N's similar to those above were produced without the
character ``E'' in the number. This AD is only concerned with those
that contain the character ``E''.
(d) Enter into the helicopter Log Book the bearing S/N.
(e) If a bearing having one of the S/N's stated in paragraph (c)
of this AD is installed on the helicopter, remove the bearing and
replace it with an airworthy bearing prior to further flight.
(f) Prior to the installation of a swashplate assembly, inspect
the bearing in accordance with the requirements of this AD.
(g) Report the results of all inspections required by this AD
within 72 hours to the Manager, Los Angeles Aircraft Certification
Office, 3960 Paramount Blvd., Lakewood, California 90712. Reporting
requirements have been approved by the Office of Management and
Budget and assigned OMB control number 2120-0056.
(h) 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, FAA. Operators shall submit their requests through an FAA
Principal Maintenance Inspector, who may concur or comment and then
send it to the Manager, Los Angeles Aircraft Certification Office.
Note 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Los Angeles Aircraft Certification Office.
Issued in Fort Worth, Texas, on January 20, 1997.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 97-2215 Filed 1-28-97; 8:45 am]
BILLING CODE 4910-13-U
