Airworthiness Directives; Bell Helicopter Textron, Inc. Model 204B, 205A, and 205A-1 Helicopters

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-SW-73-AD]

Airworthiness Directives; Bell Helicopter Textron, Inc. Model

204B, 205A, and 205A-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,

Inc. (BHTI) Model 204B, 205A, and 205A-1 helicopters, that currently

requires modification and inspections of the vertical fin spar for

cracks. This action would require modification and visual and dye-

penetrant inspections of the vertical fin spar for cracks, and if a

crack is discovered, replacing the vertical fin spar. This action would

also require a tapping test for disbonding and replacing certain fin

spars within 12 calendar months. This proposal is prompted by an

accident involving a Model 205A-1 helicopter and 4 other accidents

involving helicopters of similar type design. The actions specified by

the proposed AD are intended to prevent failure of the vertical fin

spar, loss of the tail rotor, and subsequent loss of control of the

helicopter.

DATES: Comments must be received on or before July 26, 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-73-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.

The service information referenced in the proposed rule may be

obtained from Bell Helicopter Textron, Inc., P.O. Box 482, Fort Worth,

Texas 76101, telephone (817) 280-3391, fax (817) 280-6466. This

information may be examined at the FAA, Office of the Regional Counsel,

Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas.

FOR FURTHER INFORMATION CONTACT: Harry Edmiston, Aerospace Engineer,

Rotorcraft Certification Office, Rotorcraft Directorate, FAA, 2601

Meacham Blvd., Fort Worth, Texas 76137, telephone (817) 222-5158, fax

(817) 222-5783.

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. 98-SW-73-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, Office of the Regional Counsel, Southwest Region,

Attention: Rules Docket No. 98-SW-73-AD, 2601 Meacham Blvd., Room 663,

Fort Worth, Texas 76137.

Discussion:

On May 4, 1998, the FAA issued AD 97-18-11, Amendment 39-10520 (63

FR 26429, May 13, 1998), to require modifying and inspecting the

vertical fin spar, and replacing it if a crack is found. That action

was prompted by several failures of the vertical fin spar, including

those with steel doublers, caused by fatigue cracks that result from a

large number of high-power events. The requirements of that AD are

intended to prevent failure of the vertical fin spar and subsequent

loss of control of the helicopter.

Since the issuance of that AD, there have been 4 additional

accidents involving models similar in type design to the Model 205A-1

helicopter that were caused by fatigue failure of the vertical fin

spar. The manufacturer has issued BHTI Alert Service Bulletin (ASB)

205-98-71, Revision A, dated September 21, 1998, which specifies

inspections of the vertical fin spar for cracks, and BHTI ASB No. 205-

98-73, dated September 25, 1998, which specifies replacing the vertical

fin spar assembly, part number (P/N) 205-030-899-101, 205-030-846-087

or -089, and P/N 205-032-851-003, -007, and -009, for the Model 205A

and 205A-1 helicopters. Also, the manufacturer has issued BHTI ASB No.

204B-98-50, dated October 22, 1998, which specifies inspections of the

fin spar for cracks, and replacing the fin spar assembly, P/N 205-030-

846-001, -003, -047, -049, and P/N 205-030-899-001, -089, and P/N 204-

030-825-063, -065. The FAA has further determined that the vertical fin

spar must be replaced within 12 calendar months to ensure public

safety.

Since an unsafe condition has been identified that is likely to

exist or develop on other Model 204B, 205A, and 205A-1 helicopters of

the same type design, the proposed AD would supersede AD 97-18-11 to

require initial and repetitive inspections of the vertical fin spar for

cracks. Also, replacing the vertical fin spar would be required within

12 calendar months. Replacing the vertical fin spar with a FAA-approved

vertical fin spar configuration that satisfies the structural fatigue

requirement of repeated high torque events would constitute a

terminating action for the requirements of this AD.

The FAA estimates that 150 helicopters of U.S. registry would be

affected by this proposed AD, that it would take approximately 8 work

hours per helicopter to accomplish the initial inspection and 0.5 work

hour to accomplish each repetitive inspection. Replacing the vertical

fin spar would

[[Page 28421]]

take approximately 150 work hours. The average labor rate is $60 per

work hour. The manufacturer has stated that parts will be provided at

no cost. Based on these figures, the total cost impact of the proposed

AD on U.S. operators is estimated to be $76,500 for the initial

inspection and one repetitive inspection, and $1,350,000 to replace the

vertical fin spars on the entire fleet.

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 39-10520 (63 FR

26429, May 13, 1998), and by adding a new airworthiness directive (AD),

to read as follows:

Bell Helicopter Textron, Inc.: Docket No. 98-SW-73-AD. Supersedes AD

97-18-11, Amendment 39-10520, Docket No. 97-SW-32-AD.

Applicability: Model 204B helicopters with vertical fin spar

(fin spar), part number (P/N) 205-030-899-001, -089, P/N 205-030-

846-001, -003, -047,- 049, or P/N 204-030-825-063, -065, installed,

and Model 205A and 205A-1 helicopters, with fin spar, P/N 205-030-

899-101, P/N 205-030-846-087, -089, or P/N 205-032-851-003, -007, -

009, 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 (c) 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 fin spar, loss of the tail rotor, and

subsequent loss of control of the helicopter, accomplish the

following:

(a) For Model 204B helicopters:

(1) Within 8 hours time-in-service (TIS), modify the vertical

fin and visually inspect the fin spar for cracks in accordance with

Part I (A1), paragraphs 1 through 5 of Bell Helicopter Textron

(BHTI) Alert Service Bulletin (ASB) 204B-98-50, dated October 22,

1998.

(i) If a crack is discovered on the spar, replace the fin spar

assembly with an airworthy fin spar assembly before further flight.

Repair any corrosion or disbonding discovered during the inspection

before further flight.

(ii) After inspection, apply MIL-PRF-81352 TYI clear lacquer or

equivalent to the inside of the two lower rivet holes and on the

surface where paint and primer were removed. Spray, brush or wipe on

a protective coat of MIL-C-16173, Grade 2, or equivalent, over the

clear lacquer. To facilitate subsequent inspections do not replace

the two lower rivets. See Figure 2 of BHTI ASB 204B-98-50, dated

October 22, 1998.

Note 2: BHTI-MED-SRM-1, pages 3-36 through 3-38, pertain to the

installation of Hi-Loks.

(iii) Before drilling or reaming, inspect all holes in the spar

cap where rivets were removed for short edge distance. An existing

edge distance less than 1.5 times the diameter of the drill or

reamed hole must have FAA approval of the reworked area before

proceeding.

(iv) Fasten the forward left-hand fin skin to the spar assembly

using Hi-Loks and blind rivets as specified in Figure 2 of BHTI ASB

204B-98-50, dated October 22, 1998.

(v) Refinish the reworked area.

(2) After initial modification and inspection of the fin,

thereafter inspect the fin spar for cracks at intervals not to

exceed 8 hours TIS as follows:

(i) Accomplish Part I (A2), paragraphs 1 through 3 of BHTI ASB

204B-98-50, dated October 22, 1998.

(ii) If a crack is discovered on the spar, replace the fin spar

assembly with an airworthy fin spar assembly before further flight.

Repair any corrosion or disbonding discovered during the inspection

before further flight.

(iii) After inspection, accomplish Part I (A2), paragraphs 5 and

6 of BHTI ASB 204B-98-50, dated October 22, 1998.

(3) Within 25 hours TIS, modify and inspect the vertical fin as

follows:

(i) Accomplish Part I (C1), paragraph 1 of BHTI ASB 204B-98-50,

dated October 22, 1998.

(ii) Remove sufficient rivets from the bottom row of the forward

left-hand fin skin to allow trimming of the forward left-hand fin

skin along the ``skin cutline'', approximately fin station 64.31

(see Figure 2 of BHTI ASB 204B-98-50, dated October 22, 1998).

(iii) Before drilling or reaming, inspect all holes in the spar

cap where rivets were removed for short edge distance. An existing

edge distance less than 1.5 times the diameter of the drill or

reamed hole must have FAA approval of the reworked area before

proceeding.

(iv) Accomplish Part I (C1), paragraphs 3, 4, and 6 of BHTI ASB

204B-98-50, dated October 22, 1998.

(v) If a crack is discovered on the spar, replace the fin spar

assembly with an airworthy fin spar assembly before further flight.

Repair any corrosion or disbonding discovered during the inspection

before further flight.

(vi) Accomplish Part I (C1), paragraphs 10 through 14 of BHTI

ASB 204B-98-50, dated October 22, 1998.

(4) After the initial modification and dye-penetrant inspection

of the fin spar, thereafter at intervals not to exceed 300 hours

TIS, inspect the fin spar as follows:

(i) Accomplish Part I (C2), paragraphs 1, 2, 3, 4, 5, and 7 of

BHTI ASB 204B-98-50, dated October 22, 1998.

(ii) If a crack is discovered on the spar, replace the fin spar

assembly with an airworthy fin spar assembly before further flight.

Repair any corrosion or disbonding discovered during the inspection

before further flight.

(iii) Accomplish Part I (C2), paragraphs 11 through 14 of BHTI

ASB 204B-98-50, dated October 22, 1998.

(5) Within 25 hours TIS, and thereafter at intervals not to

exceed 300 hours TIS, inspect the fin spar as follows:

(i) Accomplish Part I (B), paragraphs 1 through 13 of BHTI ASB

204B-98-50, dated October 22, 1998.

(ii) Repair any disbonding discovered during the inspection

before further flight.

[[Page 28422]]

(6) Within 12 calendar months, remove fin spar P/N 205-030-899-

001, or -089, or P/N 205-030-846-001, -003, -047, or -049, or P/N

204-030-825-063, or -065. Replace it with an airworthy fin spar

configuration that has been demonstrated to the FAA to satisfy the

structural fatigue requirements of repeated high torque events and

is approved by the Manager, Rotorcraft Standards Staff.

(7) Installation of a replacement fin spar approved by the

Manager, Rotorcraft Standards Staff, constitutes a terminating

action for the requirements of this AD.

(b) For Model 205A and 205A-1 helicopters:

(1) Within 8 hours TIS, modify the vertical fin and visually

inspect the fin spar for cracks in accordance with Part I (A1),

paragraphs 1 through 5 of BHTI ASB 205-98-71, Revision A, dated

September 21, 1998.

(i) If a crack is discovered on the spar, replace the fin spar

assembly with an airworthy fin spar assembly before further flight.

Repair any corrosion or disbonding discovered during the inspection

before further flight.

(ii) After inspection, apply MIL-PRF-81352 TYI clear lacquer or

equivalent to the inside of the two lower rivet holes and on the

surface where paint and primer were removed. Spray, brush, or wipe

on a protective coat of MIL-C-16173, Grade 2, or equivalent, over

the clear lacquer. To facilitate subsequent inspections do not

replace the two lower rivets. See figure 2 of BHTI ASB 205-98-71,

Revision A, dated September 21, 1998.

(iii) Before drilling or reaming, inspect all holes in the spar

cap where rivets were removed for short edge distance. An existing

edge distance less than 1.5 times the diameter of the drill or

reamed hole must have FAA approval of the reworked area before

proceeding.

(iv) Fasten the forward left-hand fin skin and the retainer, P/N

205-032-851-045, to the fin spar assembly using Hi-Loks and blind

rivets as specified in Figure 2 of BHTI ASB 205-98-71, Revision A,

dated September 21, 1998. Reinstall clip and radius block (if

existing) removed in paragraph 2 of Part 1 (A1) of BHTI ASB 205-98-

71, Revision A, dated September 21, 1998.

(v) Refinish the reworked area.

(2) After initial modification and inspection of the vertical

fin, thereafter, inspect the fin spar for cracks at intervals not to

exceed 8 hours TIS as follows:

(i) Accomplish Part I (A2), paragraphs 1 through 3 of BHTI ASB

205-98-71, Revision A, dated September 21, 1998.

(ii) If a crack is discovered on the spar, replace the fin spar

assembly with an airworthy fin spar assembly before further flight.

Repair any corrosion or disbonding discovered during the inspection

before further flight.

(iii) After inspection, accomplish Part I (A2), paragraphs 5 and

6, of BHTI ASB 205-98-71, Revision A, dated September 21, 1998.

(3) Within 25 hours TIS, modify and inspect the vertical fin as

follows:

(i) Accomplish Part I (C1), paragraph 1 of BHTI ASB 205-98-71,

Revision A, dated September 21, 1998.

(ii) Remove the clip, P/N 212-030-099-091, and radius block, P/N

212-030-099-095, if present. Remove the retainer, P/N 205-032-851-

045, and sufficient rivets from the bottom row of the forward left-

hand fin skin to allow trimming of the forward left-hand fin skin

along the ``skin cutline'', at approximately Fin Station 66.31 (see

Figure 2 of BHTI ASB 205-98-71, Revision A, dated September 21,

1998).

(iii) Before drilling or reaming, inspect all holes in the spar

cap where rivets were removed for short edge distance. An existing

edge distance less than 1.5 times the diameter of the drill or

reamed hole must have FAA approval of the reworked area before

proceeding.

(iv) Accomplish Part I (C1), paragraphs 3, 4, and 6 in BHTI ASB

205-98-71, Revision A, dated September 21, 1998.

(v) If a crack is discovered on the spar, replace the fin spar

assembly with an airworthy fin spar assembly before further flight.

Repair any corrosion or disbonding discovered during the inspection

before further flight.

(vi) Accomplish Part I (C1) paragraphs 10 through 14 of BHTI ASB

205-98-71, Revision A, dated September 21, 1998.

(4) After the initial modification and dye-penetrant inspection

of the fin spar, thereafter, at intervals not to exceed 300 hours

TIS, inspect the fin spar as follows:

(i) Accomplish Part I (C2), paragraphs 1, 2, 3, 4, 5, and 7 of

BHTI ASB 205-98-71, Revision A, dated September 21, 1998.

(ii) If a crack is discovered on the spar, replace the fin spar

assembly with an airworthy fin spar assembly before further flight.

Repair any corrosion or disbonding discovered during the inspection

before further flight.

(iii) Accomplish Part I (C2), paragraphs 11 through 14 of ASB

205-98-71, Revision A, dated September 21, 1998.

(5) Within 25 hours TIS, and thereafter at intervals not to

exceed 300 hours TIS inspect the fin spar as follows:

(i) Accomplish Part I (B), paragraphs 1 through 13 of BHTI ASB

205-98-71, Revision A, dated September 21, 1998.

(ii) Repair any disbonding discovered during the inspection

before further flight.

(6) Within 12 calendar months, remove fin spar, P/N 205-030-899-

001, or -089, or P/N 205-030-846-087, or -089, or P/N 205-032-851-

003, -007, or -009. Replace it with an airworthy fin spar

configuration that has been demonstrated to the FAA to satisfy the

structural fatigue requirements of repeated high torque events and

is approved by the Manager, Rotorcraft Standards Staff, or replace

it with fin spar assembly, P/N 205-530-514-103, as specified in BHTI

ASB 205-98-73, dated September 25, 1998.

(7) Installing fin spar, P/N 205-530-514-103, or a fin spar that

has been approved by the Manager, Rotorcraft Standards Staff,

constitutes terminating action for the requirements of this AD.

(c) 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 Directorate,

Rotorcraft Certification Office. Operators shall submit their

requests through a FAA Principal Maintenance Inspector, who may

concur or comment and then send it to the Manager, Rotorcraft

Certification Office.

Note 3: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Rotorcraft Certification Office.

(d) 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 May 18, 1999.

Mark R. Schilling,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 99-13319 Filed 5-25-99; 8:45 am]

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