[Federal Register Volume 64, Number 73 (Friday, April 16, 1999)]
[Proposed Rules]
[Pages 18845-18857]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-9510]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-SW-02-AD]
Airworthiness Directives; Bell Helicopter Textron-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: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the supersedure of an existing
airworthiness directive (AD), applicable to 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 that currently requires
modification and inspections of the tailboom vertical fin spar
(vertical fin spar). This action would require the same modification
and inspections plus two additional inspections, and replacement of the
vertical fin spar. This proposal is prompted by 2 accidents involving
fatigue cracks in the vertical fin spar that have occurred since the
issuance of AD 97-20-09. The actions specified by the proposed AD are
intended to prevent in-flight failure of the vertical fin spar and
subsequent loss of control of the helicopter.
DATES: Comments must be received on or before June 15, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Regional Counsel, Southwest Region,
Attention: Rules Docket No. 99-SW-02-AD, 2601 Meacham Blvd., Room 663,
Fort Worth, Texas 76137. Comments may be inspected at this location
between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal
holidays.
FOR FURTHER INFORMATION CONTACT: Charles Harrison, Aerospace Engineer,
FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, 2601 Meacham
Blvd., Fort Worth, Texas 76137, telephone (817) 222-5447, fax (817)
222-5960.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed 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 above. All
communications received on or before the closing date for comments,
specified above, will be considered before taking action on the
proposed rule. The proposals contained in this notice may be changed in
light of the comments received.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with
the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket No. 99-SW-02-AD.'' The postcard will be date stamped and
returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, (FAA), Office of the Regional Counsel, Southwest Region,
Attention: Rules Docket No. 99-SW-02-AD, 2601 Meacham Blvd., Room 663,
Fort Worth, Texas 76137.
Discussion
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 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 that result from repeated heavy lift operations
can cause fatigue cracks which will cause the vertical fin spar to
fail. After the issuance of that AD, the FAA determined that additional
model helicopters are affected by the same unsafe condition. The FAA
then issued AD 97-20-09, Amendment 39-10521, on May 4, 1998 (63 FR
26439, May 13, 1998), and added Model SW205A-1 helicopters and the Utah
State University UH-1H helicopters to the applicability of that AD.
Since the issuance of that AD, two accidents, one of which included
fatalities, have occurred. The FAA has determined that additional
inspections are needed, and replacement of the vertical fin spar, part
number (P/N) 205-030-846-all dash numbers, is required. This proposal
would require another inspection and another modification at 50 hours
TIS, and further inspections thereafter at intevals not to exceed 50
hours TIS. This proposal would also require that the vertical fin be
replaced within 12 calendar months.
Since an unsafe condition has been identified that is likely to
exist or develop on other 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 the same
type design, the proposed AD would supersede AD 97-20-09 to require
inspections, modification, and replacement of the vertical fin spar.
The FAA estimates that 75 helicopters of U.S. registry would be
affected by this proposed AD, that it would take approximately 4 work
hours to accomplish the initial inspection, 8 work hours to accomplish
the modification and the recurring inspections, and 180 hours to
replace the vertical fin spar, and that the average labor rate is $60
per work hour. Required parts would cost approximately $200 for the
modification and $15,000 for the replacement. Based on these figures,
the total cost impact of the proposed AD on U.S. operators is estimated
to be $2,004,000 to conduct an initial inspection, modify the vertical
fin spars and conduct recurring inspections, and replace the vertical
fin spars on all helicopters in the U.S. fleet.
[[Page 18846]]
The regulations proposed herein would 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
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this proposed
regulation (1) is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under the DOT
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
and (3) if promulgated, will not have a significant economic impact,
positive or negative, on a substantial number of small entities under
the criteria of the Regulatory Flexibility Act. A copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by contacting 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.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
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 removing Amendment 39-10521 (63 FR
26439, May 13, 1998), and by adding a new airworthiness directive (AD),
to read as follows:
California Department of Forestry; Firefly Aviation Helicopter
Services (Previously Erickson Air Crane Co.); Garlick Helicopters,
Inc.; Hawkins and Powers Aviation, Inc.; International Helicopters,
Inc.; Tamarack Helicopters (Previously Ranger Helicopter Services,
Inc.); Robinson Aircrane; Williams Helicopter Corporation
(Previously Scott Paper Co.); Smith Helicopters; Southern Helicopter
Inc.; Southwest Florida Aviation; Utah State University; Western
International Aviation, Inc.; UNC Helicopters; And U.S. Helicopter,
Inc.: Docket No. 99-SW-02-AD. Supersedes AD 97-20-09, Amendment 39-
10521, Docket No. 97-SW-35-AD.
Applicability: Model HH-1K (Type Certificate Data Sheet (TCDS)
H5NM), TH-lF (TCDS H12NM, and R00008AT), 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 R00008AT), UH-1H (TCDS H13WE, H3SO,
H15NM, and R00007DE), UH-lL (TCDS H5NM, H7SO, and H4NM), UH-1P (TCDS
H12NM, and R00008AT), and SW204 (TCDS H6SO), SW204HP (TCDS H6SO),
SW205 (TCDS H6SO), and SW205A-1 (TCDS H6SO) helicopters, with
tailboom vertical fin spar (vertical fin spar), part number (P/N)
205-032-899-all dash numbers, 205-030-846-all dash numbers, 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
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 (h) 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 prevent failure of the tailboom vertical fin (fin) spar and
subsequent loss of control of the helicopter, accomplish the
following:
(a) Within 8 hours time-in-service (TIS), modify the vertical
fin spar as follows:
(1) Remove the 42 deg. gearbox cover and open the drive shaft
cover on the fin spar assembly (see Figure 1).
(2) Remove the first four rivets from the fin spar located at
the bottom of the fin spar left-hand side at the tailboom and fin
spar junction, and the first four rivets aft of the junction along
the lower edge of the fin spar side-skin as shown (see Figure 2).
(3) Trim the fin spar left-hand skin using extreme care to not
damage the fin spar assembly (see Figure 3).
(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 fin spar using MS 20470AD
rivets. DO NOT install the bottom two rivets into the fin spar where
the skin was trimmed.
(6) Attach the fin spar side-skin lower edge using the rivets
specified in Figure 3.
(7) Refinish all reworked areas.
(b) After modifying the fin spar assembly, inspect the fin spar
for cracks before further flight and thereafter, at intervals not to
exceed 8 hours TIS as follows:
(1) Remove the lower aft tailboom inspection door, located at
tailboom station 180 (see Figure 1).
(2) Remove the 42 deg. gearbox cover and open the drive shaft
cover on the fin (see Figure 1).
(3) In a ventilated work area, clean all surfaces to be
inspected with a cloth dampened with aliphatic naphtha or an
equivalent cleaning solvent.
(4) Through the lower aft tailboom inspection door, using a
bright light and an inspection mirror, inspect the 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 Figures 1 and 2).
(5) Using a bright light and a 10x or higher magnifying glass,
inspect the 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 fin spar in the same area. Special attention must be
given to the left-hand edge of the fin spar and any adjacent
surfaces between fin stations 66.31 and 71.31 (see Figure 2).
(6) If any crack is discovered on the fin spar, replace the fin
spar assembly with an airworthy fin spar assembly before further
flight.
(c) Within 50 hours TIS, and thereafter at intervals not to
exceed 50 hours TIS, inspect the fin spar assembly as follows:
(1) Remove the 42 deg. gearbox cover and open the driveshaft
cover on the fin spar assembly (see Figure 1). Remove the aft lower
fin fairing and fin access panels that allow access to the aft side
of the forward fin spar and the secondary spar (see Figure 1).
(2) 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, 10x or higher
magnifying glass, and a borescope as required, inspect all of the
fin ribs, fittings, skins, and secondary aft spar of the fin
assembly (see Figures 4 and 5). Pay particular attention to the
upper and lower fittings at tailboom station 227 for cracked or
corroded fittings or sheared or loose rivets.
(3) Gain access to the canted bulkhead aft of tailboom station
194.30 through the most aft lower access covers by removing the aft
access covers or position light fairings as required. Visually
inspect the canted bulkhead forward and aft sides through the lower
tailboom inspection hole and position
[[Page 18847]]
light access holes for cracks, corrosion, or loose or sheared rivets
in all skins, fittings and bulkheads using a bright light, an
inspection mirror, and a borescope as required (see Figures 4 and
5). Pay particular attention to the area in the upper forward
corners of the aft skin directly around the fin spar assembly and
the overlap area of the top skin beneath the 42 deg. gearbox for
cracks, which are only visible from the underside.
(4) Any crack found in the fin spar assembly requires
replacement with an airworthy part. Replacing the entire fin spar
configuration with an airworthy fin spar configuration that has been
demonstrated to the FAA to satisfy the structural fatigue
requirements of repeated heavy lift operations, and is approved by
the Manager, FAA, Rotorcraft Standards Staff, will constitute a
terminating action for the requirements of this AD. Any corrosion,
loose or sheared rivets, or cracked skins or ribs found within the
inspection areas must be repaired prior to further flight.
(d) Within 50 hours TIS, modify the fin spar as follows:
(1) Remove the 42 deg. gearbox cover and open the driveshaft
cover on the fin spar assembly (see Figure 1).
(2) Remove the next 10 rivets from the fin spar located at the
bottom of the fin spar left-hand side at the tailboom and fin spar
junction (see Figures 6 and 7, whichever is applicable).
Caution: Extreme care must be taken when drilling and removing
rivets from the side of the fin spar to ensure the fin spar assembly
is not damaged.
(3) Trim the fin left-hand side skin using extreme care to not
damage the fin spar assembly to expose the spar outboard edge (See
Figure 6 or 7, whichever is applicable).
(4) Deburr the rivet holes and trimmed side skin edges. Remove
all debris. In a ventilated work area, remove any surface
contaminates with a cloth that has been dampened with aliphatic
naphtha or an equivalent cleaning solvent.
(5) Fabricate cover plates in accordance with the notes and
drawings of Figure 8 or 9, whichever is applicable. Ream prepare the
holes in the fin spar and parts and install HI-LOK fasteners.
Note 2: Bell Helicopter Medium Structural Repair Manual, BHT-
MED-SRM-1, pages 3-36 through 3-38, pertains to this installation
and reaming procedure.
(6) Refinish all reworked areas, close driveshaft and replace
42 deg. gearbox cover.
(e) After modification of the fin spar assembly, before further
flight and thereafter at intervals not to exceed 100 hours TIS,
inspect the fin spar for cracks as follows:
(1) Remove the 42 deg. gearbox cover, open the driveshaft cover
on the vertical fin spar assembly, and remove the spar cover plate
and filler plate from the lower left-hand side of the fin assembly
(see Figures 1 and 8 or 9, whichever is applicable).
Caution: Extreme care must be taken when removing the cover
plate and filler from the side of the fin spar to ensure that the
spar assembly is not damaged.
(2) In a ventilated work area, clean the surface to be inspected
with a cloth dampened with aliphatic naphtha.
Caution: Do not use chemical paint strippers. Use Scotch-Brite
Grade-A VFN and methyl-ethyl ketone (MEK) or a suitable solvent to
remove the paint and primer in the inspection area.
(3) Perform a dye-penetrant inspection of the exposed area of
the fin spar (See Figures 6 and 7).
Note 3: ASTM E1416 or MIL-STD-6866, or the Bell Helicopter
Standard Practices Manual, BHT-ALL-SPM, Chapter 6.2, pertains to
this inspection.
(4) If any crack is discovered on the fin spar, replace the fin
spar assembly with an airworthy fin spar assembly before further
flight.
(5) After inspection, apply zinc chromate primer to the bare
surfaces. When dry, re-install the cover plate and the filler using
fasteners specified in Figure 8 or 9, whichever is applicable.
(6) Install the 42 deg. gearbox cover and the driveshaft cover.
(f) Within 12 calendar months, remove the fin spar, P/N 205-030-
846-all dash numbers, P/N 205-032-899-all dash numbers, or P/N 205-
032-851-all dash numbers, whichever is applicable, and replace it
with an airworthy fin spar configuration that has been demonstrated
to the FAA to satisfy the structural fatigue requirements of
repeated heavy lift operations, and is approved by the Manager, FAA,
Rotorcraft Standards Staff.
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(g) Replacing the fin spar, P/N's 205-032-899-all dash numbers,
205-030-846-all dash numbers, or 205-032-851-all dash numbers, with
an airworthy fin spar that has been demonstrated to the FAA to
satisfy the structural fatigue requirements of repeated heavy lift
operations and approved by the Manager, FAA, Rotorcraft Standards
Staff, constitutes a terminating action for the requirements of this
AD.
(h) 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, FAA, Rotorcraft Standards Staff.
Operators shall submit their requests through an FAA Principal
Maintenance Inspector, who may concur or comment and then send it to
the Manager, FAA, Rotorcraft Standards Staff.
Note 4: Information concerning the existence of approved fin
spar configurations and alternative methods of compliance with this
AD, if any, may be obtained from the Rotorcraft Standards Staff.
(i) 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.
Issued in Fort Worth, Texas, on April 9, 1999.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 99-9510 Filed 4-15-99; 8:45 am]
BILLING CODE 4910-13-U
