[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]


-----------------------------------------------------------------------

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).

-----------------------------------------------------------------------

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.

BILLING CODE 4910-13-U

[[Page 18848]]

[GRAPHIC] [TIFF OMITTED] TP16AP99.000



[[Page 18849]]

[GRAPHIC] [TIFF OMITTED] TP16AP99.001



[[Page 18850]]

[GRAPHIC] [TIFF OMITTED] TP16AP99.002



[[Page 18851]]

[GRAPHIC] [TIFF OMITTED] TP16AP99.003



[[Page 18852]]

[GRAPHIC] [TIFF OMITTED] TP16AP99.004



[[Page 18853]]

[GRAPHIC] [TIFF OMITTED] TP16AP99.005



[[Page 18854]]

[GRAPHIC] [TIFF OMITTED] TP16AP99.006



[[Page 18855]]

[GRAPHIC] [TIFF OMITTED] TP16AP99.007



[[Page 18856]]

[GRAPHIC] [TIFF OMITTED] TP16AP99.008



BILLING CODE 4910-13-C

[[Page 18857]]

    (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