[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).


[[Page 26442]]

[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).

[[Page 26444]]

[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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