[Federal Register Volume 59, Number 214 (Monday, November 7, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-26880]
[[Page Unknown]]
[Federal Register: November 7, 1994]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 93-SW-08-AD; Amendment 39-9058; AD 94-22-09]
Airworthiness Directives; Bell Helicopter Textron, Inc.--
Manufactured Model UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, UH-1P, TH-
1F and TH-1L Helicopters
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to Bell Helicopter Textron, Inc. restricted category
military Model UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and TH-1L
helicopters, that currently requires an inspection before the first
flight of each day of certain tail rotor drive shafts and the tail
rotor drive shaft hanger bearings (bearings) for grease leakage,
security, overheat conditions, binding, or roughness until the bearings
are replaced. This amendment requires the same inspection of the
bearings, but also requires replacement of the affected bearings within
the next 100 hours time-in-service and extends the requirements of this
AD to the Model UH-1P and TH-1F helicopters that were recently type
certificated. This amendment is prompted by an accident involving a
bearing failure, and by the certification of two additional affected
helicopter models. The actions specified by this AD are intended to
prevent failure of the bearing, failure of the tail rotor drive shaft,
and subsequent loss of control of the helicopter.
DATES: Effective November 22, 1994.
Comments for inclusion in the Rules Docket must be received on or
before January 6, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Assistant Chief Counsel, Attention:
Rules Docket No. 93-SW-08-AD, 2601 Meacham Boulevard, Room 663, Fort
Worth, Texas 76137.
FOR FURTHER INFORMATION CONTACT: Mr. Uday Garadi, Aerospace Engineer,
Rotorcraft Certification Office, FAA, Rotorcraft Directorate, 2601
Meacham Boulevard, Fort Worth, Texas 76137, telephone (817) 222-5157,
fax (817) 222-5959.
SUPPLEMENTARY INFORMATION: On February 5, 1992, the FAA issued Priority
Letter (PL) AD 92-03-14, applicable to Bell Helicopter Textron, Inc.
(BHTI)-manufactured Model UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and
TH-1L helicopters, to require an inspection before the first flight of
each day of certain tail rotor
(T/R) drive shafts and T/R drive shaft hanger bearings (bearings) for
grease leakage, security, overheat conditions, binding, or roughness
until the affected bearings are replaced. That action was prompted by
an accident involving a BHTI Model 412 helicopter that experienced a
bearing failure. Inspections performed as part of the accident
investigation found metal particles from the manufacturing process in
the bearings. Contaminated bearings can seize and stop rotating,
causing the spline coupling shaft to rotate inside the bearing and
overheat. That condition, if not corrected, could result in failure of
the bearing, failure of the T/R drive shaft, and subsequent loss of
control of the helicopter.
Since the issuance of that AD, the FAA has determined that the
affected bearings need to be replaced within the next 100 hours time-
in-service in lieu of continued inspections before the first flight of
each day as required by the PL AD. In addition, Type Certificate No.
H12NM was issued March 30, 1993, to Western International Aviation,
Inc. for Model UH-1F, UH-1P, and TH-1F helicopters that use the same
bearings. Therefore, this AD should be applicable to these model
helicopters. Also, some editorial changes were made to the AD.
Since an unsafe condition has been identified that is likely to
exist or develop on other helicopters of the same type design, this AD
supersedes PL AD 92-03-14 to require the same inspection of the
affected bearings, but also to require replacement of the affected
bearings within the next 100 hours time-in-service. Due to the critical
need to ensure the integrity of the bearings that maintain control of
the T/R drive shaft through which power is provided to the T/R system,
to comply with the requirements of this AD before the first flight of
each day, and to start the required inspections on the additionally-
affected model helicopters, this rule must be issued immediately to
correct an unsafe condition in the affected helicopters.
Since a situation exists that requires the immediate adoption of
this regulation, it is found that notice and opportunity for prior
public comment hereon are impracticable, and that good cause exists for
making this amendment effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves
requirements affecting flight safety and, thus, was not preceded by
notice and an opportunity for public comment, comments are invited on
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All
communications received on or before the closing date for comments will
be considered, and this rule may be amended in light of the comments
received. Factual information that supports the commenter's ideas and
suggestions is extremely helpful in evaluating the effectiveness of the
AD action and determining whether additional rulemaking action would be
needed.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the rule that might
suggest a need to modify the 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 that
summarizes each FAA-public contact concerned with the substance of this
AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this rule must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 93-SW-08-AD.'' The postcard will be date stamped and
returned to the commenter.
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.
The FAA has determined that this regulation is an emergency
regulation that must be issued immediately to correct an unsafe
condition in aircraft, and that it is not a ``significant regulatory
action'' under Executive Order 12866. It has been determined further
that this action involves an emergency regulation under DOT Regulatory
Policies and Procedures (44 FR 11034, February 26, 1979). If it is
determined that this emergency regulation otherwise would be
significant under DOT Regulatory Policies and Procedures, a final
regulatory evaluation will be prepared and placed in the Rules Docket.
A copy of it, if filed, 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, 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 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive
(AD), Amendment 39-9058, to read as follows:
AD 94-22-09 California Department of Forestry; Garlick Helicopters;
Hawkins and Powers Aviation, Inc.; Hercules; International
Helicopters, Inc.; Offshore Construction; Oregon Helicopters; Pilot
Personnel International, Inc.; Smith Helicopters; Southern Aero
Corporation; Southwest Florida Aviation; West Coast Fabrications;
and Western International Aviation Inc.: Amendment 39-9058. Docket
Number 93-SW-08-AD. Supersedes Priority Letter AD 92-03-14, Docket
No. 91-ASW-32.
Applicability: Bell Helicopter Textron, Inc.--manufactured Model
UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, UH-1P, TH-1F, and TH-1L
helicopters, certificated in any category.
Compliance: Required as indicated, unless accomplished
previously. To prevent failure of a tail rotor (T/R) drive shaft
hanger bearing (bearing), failure of the T/R drive shaft, and
subsequent loss of control of the helicopter, accomplish the
following:
(a) Before further flight, after the effective date of this AD,
determine the serial number (S/N) etched on the seal area of the
bearing, part number (P/N) 204-040-623-005. If the bearing has a S/N
with a prefix of T or N, accomplish the inspection specified in
paragraph (b) until the affected bearing is replaced in accordance
with paragraph (d) of this AD.
Note: Bearings with a S/N prefix of NC are not required to
comply with this AD.
(b) Before the first flight of each day, until the affected
bearings are replaced in accordance with paragraph (d) of this AD,
accomplish the following inspections of the T/R drive shaft and
bearings:
(1) Visually inspect the bearings for grease leakage that
continues for more than 10 hours time-in-service after installation
of a zero-time bearing.
(2) Visually inspect the T/R drive shaft and the bearings and
housing for security and damage.
(3) Visually inspect the bearings for an overheat condition and
inspect overheat indicator stripes for discoloration.
(4) Rotate the T/R drive shaft by hand while feeling the bearing
housing for bearing binding or roughness.
(c) Before further flight, replace any bearings that exhibit
signs of continued grease leakage, overheating, binding, roughness,
or are otherwise unairworthy, and secure any insecure bearings and
housings in accordance with the applicable maintenance, repair, and
overhaul manuals.
(d) Within the next 100 hours time-in-service after the
effective date of this AD, remove from further service any bearing,
P/N 204-040-623-005, that has a S/N with a prefix of T or N, and
replace with a bearing, P/N 204-040-623-005, that has a S/N without a
prefix of T or N. Remove and replace the bearings in accordance with
the procedures in the applicable Bell Helicopter Textron, Inc.
maintenance, repair and overhaul manuals.
(e) Installation of bearings containing a prefix other than T or
N constitutes terminating action for the requirements of this AD.
(f) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used when approved by the Manager, Rotorcraft Certification Office,
FAA, Rotorcraft Directorate. Operators shall submit their requests
through an FAA Principal Maintenance Inspector, who may concur or
comment and then send it to the Manager, Rotorcraft Certification
Office.
Note: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Rotorcraft Certification Office.
(g) 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 helicopter to a location where
the requirements of this AD can be accomplished.
(h) This amendment becomes effective on November 22, 1994.
Issued in Fort Worth, Texas, on October 24, 1994.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 94-26880 Filed 11-4-94; 8:45 am]
BILLING CODE 4910-13-P
