[Federal Register Volume 63, Number 92 (Wednesday, May 13, 1998)]
[Rules and Regulations]
[Pages 26429-26439]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-12508]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-SW-32-AD; Amendment 39-10520; AD 97-18-11]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This document publishes in the Federal Register an amendment 
adopting Airworthiness Directive (AD) 97-18-11, issued on August 29, 
1997, which was sent previously to all known U.S. owners and operators 
of Bell Model 204B, 205A, and 205A-1 helicopters by individual letters. 
This AD requires modification and inspections of the vertical fin spar. 
If any crack is discovered, replacement of the vertical fin spar with 
an airworthy vertical fin spar is required before further flight. This 
amendment is 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 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, to all persons except those persons to 
whom it was made immediately effective by priority letter AD 97-18-11, 
issued on August 29, 1997, which contained the requirements of this 
amendment.
    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-32-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) 222-5783.

SUPPLEMENTARY INFORMATION: On August 29, 1997, the FAA issued priority 
letter AD 97-18-11, applicable to Bell Model 204B, 205A, and 205A-1 
helicopters, which requires modification and inspections of the 
vertical fin spar. If any crack is discovered, replacement of the 
vertical fin spar with an airworthy vertical fin spar is required 
before further flight. Priority letter AD 97-18-11 superseded priority 
letter AD 97-18-01, issued on August 19, 1997. AD 97-18-01 contained 
the same basic requirements as is contained in AD 97-18-11. However, AD 
97-18-11 was needed to clarify the method of compliance for the Model 
204B helicopters, and to correct an error in a vertical fin spar part 
number (P/N). AD 97-18-01 incorrectly stated the P/N as P/N 205-030-851 
instead of P/N 205-032-851. This AD is prompted by an accident 
involving the in-flight failure of the vertical fin spar on a Model 
205A-1 helicopter. Two other accidents on restricted category (military 
surplus) aircraft of similar type design have occurred. One of the 
accidents resulted in a fatality. In 1971, the FAA issued AD 71-21-02, 
which addressed this problem by requiring the addition of a steel 
doubler to the inside edge of the vertical fin spar. There have been 
several additional failures since that AD was issued. 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 unsafe condition described is likely to exist or develop 
on other Bell

[[Page 26430]]

Model 204B, 205A, and 205A-1 helicopters of the same type design, the 
FAA issued priority letter AD 97-18-11 to prevent in-flight failure of 
the vertical fin spar and subsequent loss of control of the helicopter. 
The AD requires, within 8 hours time-in-service (TIS) after the 
effective date of this AD, modification and inspection of the vertical 
fin spar. Then, at intervals not to exceed 8 hours TIS, further 
inspections of the vertical fin spar for cracks are required. If any 
crack is discovered, replacement of the vertical fin spar with an 
airworthy vertical fin spar is required before further flight.
    Since it was found that immediate corrective action was required, 
notice and opportunity for prior public comment thereon were 
impracticable and contrary to the public interest, and good cause 
existed to make the AD effective immediately by individual letters 
issued on August 29, 1997 to all known U.S. owners and operators of 
Bell Model 204B, 205A, and 205A-1 helicopters. These conditions still 
exist, and the AD is hereby published in the Federal Register as an 
amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 
39.13) to make it effective to all persons.
    The FAA estimates that 265 helicopters will be affected by this 
proposed AD, that it will take approximately 203 work hours to 
accomplish the modification, inspection, and spar replacement, and that 
the average labor rate is $60 per work hour. Based on these figures, 
the total cost impact of the AD on U.S. operators is estimated to be 
$3,227,700.

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-32-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, 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) to read as follows:

    AD 97-18-11  Bell Helicopter Textron: Amendment 39-10520. Docket 
No. 97-SW-32-AD.

    Applicability: Model 204B, 205A, and 205A-1 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 (c) 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) For Model 204B helicopters, 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).
    (i) 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 
skin (skin) as shown (see Figure 2). CAUTION: Extreme care must be 
taken when drilling and removing rivets from the side of vertical 
fin spar to ensure the vertical fin spar assembly is not damaged.
    (ii) Trim the vertical fin spar left-hand skin using extreme 
care to not damage the vertical fin spar assembly (see Figure 3).
    (iii) 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.

[[Page 26431]]

    (iv) Reattach the 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.
    (v) Reinstall the vertical fin spar skin lower edge rivets using 
M 7885/6-5 rivets (see Figure 6).
    (vi) Refinish all reworked areas.
    (vii) After modifying the vertical fin spar, immediately inspect 
the vertical fin spar in accordance with paragraphs (a)(2)(iii) and 
(a)(2)(iv) of this AD.
    (2) After the initial modification and inspection of the 
vertical fin spar have been accomplished in accordance with 
paragraph (a)(1) of this AD, thereafter, at intervals not to exceed 
8 hours TIS, inspect the vertical fin spar in accordance with 
paragraphs (a)(2)(iii) and (a)(2)(iv) of this AD for cracks as 
follows:
    (i) Remove the lower aft tailboom inspection door, located at 
tailboom station 180 (see Figure 4).
    (ii) Remove the 42 deg. gearbox cover and open the drive shaft 
cover on the vertical fin (see Figure 1).
    (iii) 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 5).
    (iv) 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 5).
    (3) If any crack is discovered on the vertical fin spar as a 
result of the inspection specified in paragraphs (a)(2)(iii) or 
(a)(2)(iv) of this AD, replace the vertical fin spar assembly with 
an airworthy vertical fin spar assembly before further flight.
    (b) For Model 205A and 205A-1 helicopters, within 8 hours 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).
    (i) Remove the clip, P/N 212-030-099-091, and the radius block, 
P/N 212-030-099-095, (see Figures 5 and 6).
    (ii) 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 as shown (see Figure 5). 
CAUTION: Extreme care must be taken when drilling and removing 
rivets from the side of vertical fin spar to ensure the vertical fin 
spar assembly is not damaged.
    (iii) Trim the vertical fin left-hand side skin and retainer, P/
N 205-032-851-045, using extreme care to not damage the vertical fin 
spar assembly (see Figure 7).
    (iv) Deburr the rivet holes and trimmed retainer and 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.
    (v) Reattach the skin and retainer to the vertical fin spar 
using MS 20470AD rivets. DO NOT install the bottom two rivets into 
the vertical fin spar where the skin and retainer were trimmed.
    (vi) Reinstall the clip and radius block with M 7885/6-5 rivets 
(see Figure 5).
    (vii) Refinish all reworked areas.
    (viii) After modifying the vertical fin spar, immediately 
inspect the vertical fin spar in accordance with paragraphs 
(b)(2)(iii) and (b)(2)(iv) of this AD.
    (2) After the initial modification and inspection of the 
vertical fin spar have been accomplished in accordance with 
paragraph (b)(1) of this AD, thereafter, at intervals not to exceed 
8 hours TIS, inspect the vertical fin spar in accordance with 
paragraphs (b)(2)(iii) and (b)(2)(iv) of this AD for cracks as 
follows:
    (i) Remove the lower aft tailboom inspection door, located at 
tailboom station 180 (see Figure 4).
    (ii) Remove the 42 deg. gearbox cover and open the drive shaft 
cover on the vertical fin spar (see Figure 1).
    (iii) 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 5).
    (iv) 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 5).
    (3) If any crack is discovered on the vertical fin spar as a 
result of the inspection specified in paragraphs (b)(2)(iii) or 
(b)(2)(iv) of this AD, replace the vertical fin spar assembly with 
an airworthy vertical fin spar assembly before further flight.
    (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, 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.

    (d) 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.

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    (e) This amendment becomes effective on May 28, 1998, to all 
persons except those persons to whom it was made immediately effective 
by Priority Letter AD 97-18-11, issued August 29, 1997, which contained 
the requirements of this amendment.

    Issued in Fort Worth, Texas, on May 4, 1998.
Eric Bries.
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 98-12508 Filed 5-12-98; 8:45 am]
BILLING CODE 4910-13-C