[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]


-----------------------------------------------------------------------


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).

-----------------------------------------------------------------------

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