[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