[Federal Register Volume 63, Number 92 (Wednesday, May 13, 1998)]
[Rules and Regulations]
[Pages 26439-26445]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-12509]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-SW-35-AD; Amendment 39-10521; AD 97-20-09]
RIN 2120-AA64
Airworthiness Directives; Bell Helicopter Textron (Bell)-
manufactured Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-
1H, UH-1L, and UH-1P Helicopters; and Southwest Florida Aviation SW204,
SW204HP, SW205, and SW205A-1 Helicopters
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment supersedes an existing priority letter
airworthiness directive (AD), applicable to Bell-manufactured Model HH-
1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P
helicopters; and Southwest Florida Aviation SW204, SW204HP, and SW205
helicopters, that currently requires modification and inspections of
the vertical fin spar. This amendment requires the same modification
and inspections required by the existing priority letter AD, but adds
the Southwest Florida Aviation Model SW205A-1 and Utah State University
UH-1H helicopters to the applicability of this AD. This amendment is
prompted by accidents involving in-flight failure of the tailboom
vertical fin spar. The actions specified by this AD are intended to
prevent in-flight failure of the vertical fin spar and subsequent loss
of control of the helicopter.
DATES: Effective May 28, 1998.
Comments for inclusion in the Rules Docket must be received on or
before July 13, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Regional Counsel, Southwest Region,
Attention: Rules Docket No. 97-SW-35-AD, 2601 Meacham Blvd., Room 663,
Fort Worth, Texas 76137.
FOR FURTHER INFORMATION CONTACT: Mr. Charles Harrison, Aerospace
Engineer, FAA, Rotorcraft Directorate, Rotorcraft Certification Office,
2601 Meacham Blvd., Fort Worth, Texas 76137, telephone (817) 222-5447,
fax (817) 222-5960.
[[Page 26440]]
SUPPLEMENTARY INFORMATION: On September 17, 1997, the FAA issued
priority letter AD 97-20-09, applicable to Bell-manufactured Model HH-
1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P
helicopters; and Southwest Florida Aviation SW204, SW204HP and SW205
helicopters, which requires modification and inspections of the
vertical fin spar. That priority letter AD was prompted by two
accidents involving in-flight failures of the tailboom vertical fin
spars (vertical fin spars) on Model TH-lL and UH-1B helicopters. One
other accident occurred on a Model 205A-1 helicopter which is of
similar type design. One of the accidents resulted in a fatality. As a
result of those accident investigations, the FAA determined that a
large number of high-power events can cause fatigue cracks which will
cause the vertical fin spar to fail. This condition, if not corrected,
could result in in-flight failure of the vertical fin spar and
subsequent loss of control of the helicopter.
Since the issuance of that priority letter AD, the FAA has
determined that additional helicopter models are affected by the same
unsafe condition.
Since an unsafe condition has been identified that is likely to
exist or develop on other Bell-manufactured Model HH-1K, TH-1F, TH-1L,
UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P helicopters; and
Southwest Florida Aviation SW204, SW204HP, SW205, and SW205A-1
helicopters of a similar type design, this AD supersedes priority
letter AD 97-20-09 to add the Model SW205A-1 helicopters and the Utah
State University UH-1H helicopters to the applicability of this AD. The
short compliance time involved is required because the previously
described critical unsafe condition can adversely affect the structural
integrity of the helicopter. Therefore the inspections and modification
are required within 8 hours time-in-service 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.
The FAA estimates that 68 helicopters of U.S. registry would be
affected by this proposed AD, that it would take approximately 2.5 work
hours per helicopter for the initial modification and inspection, 200
work hours to replace the vertical fin spar, and that the average labor
rate is $60 per work hour. Required parts would cost approximately
$8,000 per helicopter to replace the vertical fin spar. Based on these
figures, the total cost impact of the proposed AD on U.S. operators is
estimated to be $1,370,200 to modify the vertical fin, conduct an
initial inspection, and replace the vertical fin spars on all
helicopters in the U.S. 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.
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. 97-SW-35-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,
[[Page 26441]]
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
(AD), Amendment 39-10521, to read as follows:
AD 97-20-09 California Department of Forestry; Firefly Aviation
Helicopter Services (Previously Erickson Air Crane Co.); Garlick
Helicopters, Inc.; Hawkins and Powers Aviation, Inc.; International
Helicopters, Inc.; Ranger Helicopter Services; Robinson Aircrane;
Scott Paper Co.; Smith Helicopters; Southern Helicopter; Southwest
Florida Aviation; Utah State University; Western International
Aviation, Inc.; UNC Helicopters; and U.S. Helicopter, Inc.:
Amendment 39-10521. Docket No. 97-SW-35-AD. Supersedes priority
letter AD 97-20-09.
Applicability: Model HH-1K (Type Certificate Data Sheet (TCDS)
H5NM), TH-lF (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-lL (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 tailboom vertical
fin spar, part number (P/N) 205-032-899, 205-030-846, or 205-032-
851, 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
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 (d) 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 as indicated, unless accomplished
previously.
To prevent in-flight failure of the tailboom vertical fin spar
(vertical fin spar) and subsequent loss of control of the
helicopter, accomplish the following:
(a) Within 8 hours time-in-service (TIS) after the effective
date of this AD, modify the vertical fin spar as follows:
(1) Remove the 42 deg. gearbox cover and open the drive shaft
cover on the vertical fin spar assembly (see Figure 1).
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[GRAPHIC] [TIFF OMITTED] TR13MY98.026
(2) Remove the first four rivets from the vertical fin spar
located at the bottom of the vertical fin spar left-hand side at the
tailboom and vertical fin spar junction, and the first four rivets
aft of the junction along the lower edge of the vertical fin spar
side-skin as shown (see Figure 2).
Caution: Extreme care must be taken when drilling and removing
rivets from the side of the vertical fin spar to ensure the vertical
fin spar assembly is not damaged.
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[[Page 26443]]
[GRAPHIC] [TIFF OMITTED] TR13MY98.027
(3) Trim the vertical fin spar left-hand skin using extreme care to
not damage the vertical fin spar assembly (see Figure 3).
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[GRAPHIC] [TIFF OMITTED] TR13MY98.028
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[[Page 26445]]
(4) Deburr the rivet holes and trimmed skin edges. Remove all
debris. In a ventilated work area, remove any surface contaminants
with a cloth that has been dampened with aliphatic naphtha or an
equivalent cleaning solvent.
(5) Reattach the side-skin to the vertical fin spar using MS
20470AD rivets. DO NOT install the bottom two rivets into the
vertical fin spar where the skin was trimmed.
(6) Reinstall the vertical fin spar skin lower edge rivets using
M 7885/6-5 rivets (see Figure 2).
(7) Refinish all reworked areas.
(8) After modifying the vertical fin spar, immediately inspect
the vertical fin spar in accordance with paragraphs (b)(3) and
(b)(4) of this AD.
(b) After the initial modification and inspection of the
vertical fin spar have been accomplished in accordance with
paragraph (a) of this AD, thereafter, at intervals not to exceed 8
hours TIS, inspect the vertical fin spar for cracks as follows:
(1) Remove the lower aft tailboom inspection door, located at
tailboom station 180 (see Figure 4).
[GRAPHIC] [TIFF OMITTED] TR13MY98.029
(2) Remove the 42 deg. gearbox cover and open the drive shaft
cover on the vertical fin (see Figure 1).
(3) Through the lower aft tailboom inspection door, using a
bright light and an inspection mirror, inspect the vertical fin spar
assembly adjacent to the tailboom top skin on the forward side,
paying special attention to the left-hand edge and the adjacent
surfaces (see Figure 2).
(4) In a ventilated work area, clean all surfaces to be
inspected with a cloth dampened with aliphatic naphtha or an
equivalent cleaning solvent. Using a bright light and a 10x
magnifying glass, inspect the vertical fin spar assembly adjacent to
the tailboom top-skin on the in-board and out-board sides, the
vertical edge, and the two open rivet holes. Using a bright light
and a mirror, inspect the aft side of the vertical fin spar in the
same area. Special attention must be given to the left-hand edge of
the vertical fin spar and any adjacent surfaces between fin stations
66.31 and 71.31 (see Figure 2).
(c) If any crack is discovered on the vertical fin spar as a
result of the inspection specified in paragraphs (b)(3) or (b)(4) of
this AD, replace the vertical fin spar assembly with an airworthy
vertical fin spar assembly before further flight.
(d) 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 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, Rotorcraft Certification Office.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Rotorcraft Certification Office.
(e) Special flight permits may be issued in accordance with
Secs. 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.
(f) This amendment becomes effective on May 28, 1998.
Issued in Fort Worth, Texas, on May 4, 1998.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 98-12509 Filed 5-12-98; 8:45 am]
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