[Federal Register Volume 64, Number 101 (Wednesday, May 26, 1999)]
[Proposed Rules]
[Pages 28418-28420]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-13318]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-SW-30-AD]


Airworthiness Directives; Bell Helicopter Textron, A Division of 
Textron Canada, Model 206L, L-1, L-3, and L-4 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, A 
Division of Textron Canada (BHTC) Model 206L, L-1, L-3, and L-4 
helicopters. This action would require the same type of actions 
required by the existing AD. In addition, the proposal would require an 
increase in the Retirement Index Number (RIN) multiplier for the mast, 
a correction in the model number, and other nonsubstantive changes. 
This proposal is prompted by further tests and analyses that indicate 
the RIN multiplier for the Model 206L-4 needs to be increased and the 
discovery of other errors in the existing AD. The actions specified by 
the proposed AD are intended to prevent fatigue failure of the mast or 
trunnion, which could result in loss of the main rotor system 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. 99-SW-30-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, a Division of Textron Canada, 
12,800 Rue de L-Avenir, Mirabel, Quebec, Canada J7J1R4, ATTN: Product 
Support Engineering Light Helicopters. 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: Jurgen Priester, Aerospace Engineer, 
Rotorcraft Certification Office, Rotorcraft Directorate, FAA, 2601 
Meacham Blvd., Fort Worth, Texas 76137, telephone (817) 222-5159, fax 
(817) 222-5959.

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-30-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. 99-SW-30-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137.

Discussion

    On March 14, 1997, the FAA issued AD 97-07-07, Amendment 39-9981 
(62 FR 16073). The AD required the creation of a component history card 
or equivalent record using the RIN system for certain masts and 
trunnions within the next 100 hours time-in-service (TIS) and a system 
for tracking increases to the accumulated RIN. That AD also established 
a retirement life for the trunnion based solely on a RIN of 24,000 and 
a retirement life for the mast based on a maximum RIN of 44,000 or the 
flight-hour service life limit, whichever occurs first. That AD was 
prompted by fatigue analyses and tests that show certain masts and 
trunnions fail sooner than originally anticipated because of the 
unanticipated higher number of torque events performed with those masts 
and trunnions in addition to the TIS accrued under other operating 
conditions. That condition, if not corrected, could result in fatigue 
failure of the mast or trunnion, which could result in loss of the main 
rotor system and subsequent loss of control of the helicopter.
    Since the issuance of that AD, the FAA has discovered that the AD 
contained errors in two paragraphs. Paragraph (c)(2) incorrectly 
requires the operator to increase the mast RIN count for the Model 
206L-4 by 1, when it should actually be increased by 2, for each torque 
event. Paragraph (c)(1)(i) contains an omission of the letter ``L'' 
from one helicopter model number. This AD would correct paragraph 
(c)(2) to avoid a miscalculation of the mast RIN and to correctly 
identify the Model 206L. This AD would also add nonsubstantive changes 
to the text. Paragraphs (b) and (c) would state that the RIN may be 
recorded on an ``equivalent record'' in lieu of a component history 
card. Paragraph (d) and (e) would state that this AD revises the 
Limitations section of the maintenance manual.

Explanation of Relevant Service Information

    Bell Helicopter Textron, Inc. has issued Alert Service Bulletin No. 
206L-94-99, Revision A, dated May 1, 1995 (ASB), which describes 
procedures for calculating the retirement life based on the RIN count.

FAA's Conclusions

    These helicopter models are manufactured in Canada and are type 
certificated for operation in the United States under the provisions of 
section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and 
the applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, Transport Canada has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of Transport Canada, reviewed all available information, and 
determined that AD action is necessary for products of this

[[Page 28419]]

type design that are certificated for operation in the United States.
    Since an unsafe condition has been identified that is likely to 
exist or develop on BHTC Model 206L, L-1, L-3, and L-4 helicopters of 
the same type designs registered in the United States, the proposed AD 
would supersede AD 97-07-07 to prevent miscalculation of a RIN for 
Model 206L-4 main rotor masts. This AD would require creation of a 
component history card or equivalent record using a RIN system, 
establishing a system for tracking increases to the accumulated RIN, 
and a maximum accumulated RIN for masts and trunnions. The actions 
would be required to be accomplished in accordance with the ASB 
described previously.
    The FAA estimates that 711 helicopters of U.S. registry would be 
affected by this AD, that it would take approximately (1) 8 work hours 
per helicopter to replace the mast and 10 work hours per helicopter to 
replace the trunnion due to the new method of determining the 
retirement life required by this AD; (2) 2 work hours per helicopter to 
create the component history card of equivalent record (record); (3) 10 
work hours per helicopter to maintain the record each year, and that 
the average labor rate is $60 per work hour. Required parts would cost 
approximately $9,538 per mast and $2,083 per trunnion. Based on these 
figures, the cost impact of the AD on U.S. operators for the first year 
is estimated to be $2,016,989, and each subsequent year to be 
$1,945,889. These costs assume replacement of the mast and trunnion in 
one-sixth of the fleet each year, creation and maintenance of the 
records for all the fleet the first year, and creation of one-sixth of 
the fleet's records and maintenance of the records for all the fleet 
each subsequent year. The estimated cost impact amounts are based on 
assumptions that no operator has yet accomplished any of the 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted.
    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, would 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 39-9981, Docket 
No. 95-SW-36-AD (62 FR 16073, dated April 4, 1997) and by adding a new 
airworthiness directive (AD) to read as follows:

Bell Helicopter Textron, A Division of Textron Canada: Docket No. 
99-SW-30-AD. Supersedes AD 97-07-07, Amendment 39-9981, Docket 95-
SW-36-AD.

    Applicability: Model 206L, 206L-1, 206L-3, and 206L-4 
helicopters, with main rotor mast (mast), part number (P/N) 206-040-
535-001, -005, -101, or -105, installed, or main rotor trunnion 
(trunnion), P/N 206-011-120-103, 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 request approval for an 
alternative method of compliance in accordance with paragraph (f) 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 within 100 hours time-in-service, unless 
accomplished previously.
    To prevent fatigue failure of the mast or trunnion, which could 
result in loss of the main rotor system and subsequent loss of 
control of the helicopter, accomplish the following:
    (a) Create a component history card or an equivalent record for 
the affected mast and trunnion.
    (b) Determine the accumulated Retirement Index Number (RIN) to 
date based on the number of takeoffs and external load lifts (torque 
events) for parts in service in accordance with paragraphs 1 and 2 
of the Accomplishment Instructions of Bell Helicopter Textron, Inc. 
Alert Service Bulletin No. 206L-94-99, Revision A, dated May 1, 1995 
(ASB). Record this accumulated RIN on the component history card or 
equivalent record.
    (c) After complying with paragraphs (a) and (b) of this AD, 
during each operation thereafter, maintain a count of the number of 
external load lifts and the number of takeoffs performed and at the 
end of each day's operations, increase the accumulated RIN on the 
component history card or equivalent record as follows:
    (1) For the trunnion,
    (i) Increase the RIN for the Model 206L, 206L-1, and 206L-3 
helicopters by 1 for each torque event.
    (ii) Increase the RIN for the Model 206L-4 helicopters by 2 for 
each torque event.
    (2) For the mast,
    (i) Increase the RIN for the Model 206L, 206L-1, 206L-3 
helicopters by 1 for each torque event.
    (ii) Increase the RIN for the Model 206L-4 helicopters by 2 for 
each torque event.

    Note 2: Previous Model 206L-4 mast RIN calculations may have 
increased the RIN by only 1 for each torque event. This AD increases 
the Model 206L-4 mast RIN by 2 for each torque event.

    (d) Remove the trunnion from service on or before attaining the 
maximum accumulated RIN (24,000) in accordance with Table 1 of the 
Accomplishment Instructions of the ASB. This AD revises the 
Limitations section of the maintenance manual by establishing a 
retirement life of 24,000 RIN for the trunnion.
    (e) Remove the mast from service on or before attaining the 
maximum accumulated RIN (44,000) or the flight hour service life 
limit, whichever occurs first, in accordance with Table 2 of the 
Accomplishment Instructions the ASB. This AD revises the Limitations 
section of the maintenance manual by establishing a retirement life 
of 44,000 RIN for the mast.
    (f) 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, 
Rotorcraft Directorate, FAA. Operators shall submit their requests 
through an appropriate FAA Principal Maintenance Inspector, who may 
add comments 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

[[Page 28420]]

obtained from the Rotorcraft Certification Office.

    (g) 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. 99-13318 Filed 5-25-99; 8:45 am]
BILLING CODE 4910-13-P