[Federal Register Volume 64, Number 62 (Thursday, April 1, 1999)]
[Rules and Regulations]
[Pages 15661-15669]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-7778]
[[Page 15661]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-SW-31-AD; Amendment 39-11101; AD 99-07-15]
RIN 2120-AA64
Airworthiness Directives; Bell Helicopter Textron, Inc.-
manufactured Model HH-1K, SW204, SW204HP, SW205, SW205A-1, TH-1F, TH-
1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P Helicopters
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to Bell Helicopter Textron, Inc. (BHTI)-manufactured
Model HH-1K, SW204, SW204HP, SW205, SW205A-1, TH-1F, TH-1L, UH-1A, UH-
1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P helicopters. This action
requires inspecting the tail rotor yoke (yoke) assembly historical
records to determine if the affected yoke assembly has been involved in
any incidents that may have induced a bending load. It further requires
replacement of the yoke assembly with a yoke assembly that has been x-
ray diffraction inspected or has zero hours time-in-service (TIS);
installing and inspecting an airworthy flapping stop or trunnion
assembly to detect excessive bending loads; and revising the applicable
Rotorcraft Flight Manual. This amendment is prompted by in-flight
failures of yokes installed on civilian and military helicopters of
similar type design, including three reported accidents. The actions
specified in this AD are intended to detect static or dynamic overload
on the yoke due to external bending forces, which could result in
failure of the yoke, loss of the tail rotor, and subsequent loss of
control of the helicopter.
DATES: Effective May 3, 1999.
Comments for inclusion in the Rules Docket must be received on or
before June 1, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Regional Counsel, Southwest Region,
Attention: Rules Docket No. 98-SW-31-AD, 2601 Meacham Blvd., Room 663,
Fort Worth, Texas 76137.
FOR FURTHER INFORMATION CONTACT: Charles Harrison, Aerospace Engineer,
FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, 2601 Meacham
Blvd., Fort Worth, Texas 76137, telephone (817) 222-5128, fax (817)
222-5961.
SUPPLEMENTARY INFORMATION: This amendment adopts a new AD that is
applicable to BHTI-manufactured Model HH-1K, SW204, SW204HP, SW205,
SW205A-1, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and
UH-1P helicopters. This action requires, before further flight,
inspecting the yoke assembly historical records to determine if it has
been involved in any incidents that may have induced a bending load in
the yoke, and if so, immediately replacing the yoke assembly with a
yoke assembly that has been x-ray diffraction inspected or has zero
hours TIS as well as replacing the flapping stop or trunnion assembly.
It further requires, within the next 180 calendar days, for yokes other
than those that are required to be replaced before further flight,
removing and replacing the yoke assembly with an airworthy assembly.
This AD also requires inspection of the replaced trunnion assembly or
flapping stop at intervals not to exceed 25 hours time-in-service
(TIS), or before further flight, after any incident involving a hard
landing, or any other incident involving excessive tail rotor flapping
loads. Examples of bending loads include high wind gusts (such as those
from prop blast), improper ground handling (in which the tail rotor
blade has been used as a hand hold), improper feathering bearing
removal (in which the yoke is not properly supported when pressing out
bearings), or a static ground strike of some type (such as being struck
by a vehicle). This amendment is prompted by reports of in-flight
failures of yokes installed on civilian and military helicopters of
similar type design, including 3 reported accidents. The actions
specified in this AD are intended to detect static or dynamic overload
on the yoke due to external bending forces, which could result in
failure of the yoke, loss of the tail rotor, and subsequent loss of
control of the helicopter.
Since an unsafe condition has been identified that is likely to
exist or develop on other BHTI Model HH-1K, SW204, SW204HP, SW205,
SW205A-1, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and
UH-1P helicopters of the same type design, this AD is being issued to
detect static or dynamic overload on the yoke due to excessive bending
forces, which could result in failure of the yoke, loss of the tail
rotor, and subsequent loss of control of the helicopter. The short
compliance time involved is required because the previously described
critical unsafe condition can adversely affect the controllability and
structural integrity of the helicopter tail rotor. Therefore, the
actions contained in the AD are required prior to further flight, and
this AD must be issued immediately.
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.
Cost Impact
The FAA estimates that 75 helicopters will be affected by this AD,
that it will take approximately 9 work hours to accomplish the
inspections and installations, and that the average labor rate is $60
per work hour. Required parts will cost approximately $6,637 per yoke,
and $936 per flapping stop or $1,028 per trunnion. Based on these
figures, the total cost impact of the AD on U.S. operators is estimated
to be $608,475 to replace the yoke and flapping stop in the entire
fleet, or $615,375 to replace the yoke and trunnion in the entire
fleet.
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
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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 No. 98-SW-31-AD.'' The postcard will be date stamped and
returned to the commenter.
Regulatory Impact
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. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive
to read as follows:
AD. 99-07-15 California Department of Forestry; Firefly Aviation
Helicopter Services (Previously Erickson Air-Crane); Garlick
Helicopters; Hawkins & Powers Aviation, Inc.; International
Helicopters, Inc.; Ranger Helicopter Services; Robinson Aircrane,
Inc.; Scott Paper Co. (Formerly Off Shore); Smith Helicopters;
Southern Helicopter, Inc.; Southwest Florida Aviation; Utah State
University; UNC Helicopter Inc. (Formerly Williams Helicopter); US
Helicopter, Inc.; and Western International Aviation Inc.: Amendment
39-11101. Docket No. 98-SW-31-AD. q
Applicability: Model HH-1K (Type Certificate Data Sheet (TCDS)
H5NM), TH-1F (TCDS H12NM, and R0008AT), TH-1L (TCDS H5NM, H7SO, and
H4NM), UH-1A (TCDS H3SO), UH-1B (TCDS H1RM, H3NM, H13WE, H3SO, H5SO,
and R00012AT), UH-1E (TCDS H5NM, H7SO, H8NM, and H4NM), UH-1F (TCDS
H2NM, H7NE, H11SW, H12NM, and R0008AT), UH-1H (TCDS H13WE, H3SO, and
H15NM), UH-1L (TCDS H5NM, H7SO, and H4NM), UH-1P (TCDS H12NM, and
R0008AT), and SW204 (TCDS H6SO), SW204HP (TCDS H6SO), SW205 (TCDS
H6SO), and SW205A-1 (TCDS H6SO) helicopters, with tail rotor yoke,
part number (P/N) 212-011-702-all dash numbers, P/N 212-010-704-all
dash numbers, or P/N 212-010-744-all dash numbers, installed,
certificated in any category.
Note 1: This AD applies to each helicopter identified in the
preceding applicability provision, regardless of whether it has been
otherwise 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 request approval for an
alternative method of compliance in accordance with paragraph (g) 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 detect static or dynamic overload on the tail rotor yoke
(yoke) due to external bending forces, which could result in failure
of the yoke, loss of the tail rotor, and subsequent loss of control
of the helicopter, accomplish the following:
(a) Before further flight, review all historical records of the
helicopter and the identified yoke assembly for any static or
dynamic incident history that could have imposed an excessive
bending load on the yoke. If such a history exists, before further
flight, replace the yoke assembly with a yoke assembly specified in
paragraph (c) and install the flapping stop or trunnion assembly as
specified in paragraph (d).
Note 2: Examples of excessive bending loads include exposure to
high wind gusts (such as those from rotor wash or prop blast),
improper ground handling (in which the tail rotor blade has been
used as a hand hold), improper feathering bearing removal (in which
the yoke is not properly supported when pressing out bearings), or
an incident in which a damaged tail rotor blade was replaced due to
a static ground blade strike.
(b) Identify the trunnion assembly or flapping stop that is
installed on the aircraft tail rotor assembly to determine if it is
a flapping stop or trunnion and, if it is a flapping stop, to
determine if the correct flapping stop is installed (see Figures 1
and 2).
Note 3: Helicopters with yoke assemblies, P/N 212-010-704-all
dash numbers or P/N 212-010-744-all dash numbers, have trunnion
assemblies installed that look similar. Trunnion assemblies, P/N
205-012-716-001 and P/N 212-010-703-001, are manufactured from
machined material and do not have the proper characteristics to act
as a yield indicators for the yoke assembly. When installed, these
trunnion assemblies may be identified by the presence of a flanged
bushing (split lines) at each bolt hole, readily visible externally
when viewed inboard of the trunnion halves adjacent to each bearing.
The trunnion assembly, P/N 212-010-738-001, is manufactured from a
casting and does not incorporate bushings at the bolt locations. No
bushing will be visible when viewing the assembled trunnion.
Helicopters with yoke assemblies, P/N 212-011-702-all dash numbers,
are assembled with a flapping stop configuration. The original
flapping stop, P/N 212-011-713-001 has been redesigned. The
redesigned flapping stop, P/N 212-011-713-103, will act as a yield
indicator to provide visual verification of a yoke assembly that has
been subjected to excessive out-of-plane bending loads (see Figure
5).
(c) Within the next 180 calendar days (for yokes not replaced
immediately in accordance with paragraph (a) of this AD), remove the
yoke assembly and replace it with an airworthy yoke assembly having
zero hours time-in-service (TIS), or with an airworthy yoke assembly
(regardless of TIS) that has passed an X-ray diffraction inspection
in accordance with Part II of Bell Helicopter Textron, Inc. Alert
Service Bulletin 212-96-100, Revision A, dated May 18, 1998.
(d) When the yoke assembly is replaced, for helicopters with a
yoke assembly, P/N 212-011-702-all dash numbers, install an
airworthy tail rotor flapping stop, P/N 212-011-713-103, and for
helicopters with yoke assemblies, P/N 212-010-704-all dash numbers
or P/N 212-010-744-all dash numbers, install an airworthy trunnion
assembly, P/N 212-010-738-001. If any incident as described in
paragraph (a) of this AD occurs after the effective date of this AD
and prior to compliance with paragraph (c), then compliance with
paragraphs (c) and (d) is required before further flight.
Note 4: Yoke assemblies that have passed an x-ray diffraction
inspection at BHTI will have the letters ``FM'' vibro-etched on them
following the serial number.
(e) After accomplishing the requirements of paragraphs (c) and
(d) of this AD, thereafter,
[[Page 15663]]
at intervals not to exceed 25 hours TIS, or before further flight
after any incident as described in paragraph (a) of this AD, inspect
the trunnion assembly or flapping stop as follows:
(1) Gain access to the tail rotor assembly to allow close
viewing of the inboard section of the trunnion assembly or flapping
stop, whichever is installed. Perform a visual inspection of the
inboard section of the trunnion assembly (see Figure 3) or the
flapping stop (see Figure 4) for deformation. Inspect by gently
placing the tail rotor yoke against one flapping stop or trunnion
stop, allowing full view of the opposite stop. Repeat in opposite
direction to allow viewing of the opposite stop.
(2) If either the trunnion stop or flapping stop is deformed or
bent as shown in Figure 3 or Figure 4, the yoke assembly and
trunnion stop or flapping stop are no longer serviceable and must be
replaced with an airworthy yoke assembly that has zero hours TIS or
has passed x-ray diffraction inspection, and an airworthy flapping
stop or trunnion stop.
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(f) Within 30 calendar days after the effective date of this AD,
insert the following pen and ink changes under the Operating
Procedures and Maneuvers Pre-Flight Checks section of the Rotorcraft
Flight Manual or Operational Manual:
``Tail rotor yoke--Preflight visual check for static stop
contact damage (deformed static stop or trunnion yield indicator).''
Note 5: Operators who use aircraft that have any of these
affected yoke assemblies installed should use tail rotor tie downs
when the aircraft is parked or stored.
(g) 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, Rotorcraft Standards Staff,
Rotorcraft Directorate, FAA. Operators shall submit their requests
through an FAA Principal Maintenance Inspector, who may concur or
comment and then send it to the Manager, Rotorcraft Standards Staff.
Note 6: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Rotorcraft Certification Office.
(h) 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.
(i) This amendment becomes effective on May 3, 1999.
Issued in Fort Worth, Texas, on March 23, 1999.
Mark R. Schilling,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 99-7778 Filed 3-31-99; 8:45 am]
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