[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