[Federal Register Volume 62, Number 97 (Tuesday, May 20, 1997)]
[Rules and Regulations]
[Pages 27496-27497]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-13084]



[[Page 27496]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-SW-20-AD; Amendment 39-10033; AD 97-11-04 ]
RIN 2120-AA64


Airworthiness Directives; Bell Helicopter Textron, Inc. Model 412 
and 412EP Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to Bell Helicopter Textron, Inc. (BHTI) Model 412 and 412EP 
helicopters, that requires creation of a component history card or 
equivalent record using a Retirement Index Number (RIN) system; 
establishes a system for tracking increases to the accumulated RIN; and 
establishes a maximum accumulated RIN for certain main rotor masts 
(masts) and main rotor spline plates (spline plates). This amendment is 
prompted by fatigue analyses and tests that show certain masts and 
spline plates fail earlier than originally anticipated because of an 
unanticipated high number of takeoffs and external load lifts utilizing 
high power settings, in addition to the time-in-service (TIS) accrued 
under normal operating conditions. The actions specified by this AD are 
intended to prevent fatigue failure of the mast or spline plate, which 
could result in failure of the main rotor system and subsequent loss of 
control of the helicopter.

EFFECTIVE DATE: June 24, 1997.

FOR FURTHER INFORMATION CONTACT: Mr. Uday Garadi, Aerospace Engineer, 
FAA, Rotorcraft Certification Office, Rotorcraft Directorate, Fort 
Worth, Texas 76193-0170, telephone (817) 222-5157, fax (817) 222-5959.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to BHTI Model 412 and 412EP 
helicopters was published in the Federal Register on November 20, 1996 
(61 FR 59034). That action proposed to require, within the next 100 
hours TIS, creation of a component history card or equivalent record 
using a RIN system for certain masts and spline plates used on the 
Model 412 and 412EP helicopters; establishment of a system for tracking 
increases to the accumulated RIN; and establishment of a retirement 
life of 80,000 RIN for certain helicopter masts and spline plates, and 
a retirement life of 60,000 RIN for certain other helicopter masts and 
spline plates.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were received on the 
proposal or the FAA's determination of the cost to the public. The FAA 
has determined that air safety and the public interest require the 
adoption of the rule as proposed, with editorial changes. The FAA has 
determined that these changes will neither increase the economic burden 
on any operator nor increase the scope of the AD.
    The FAA estimates that 294 helicopters of U.S. registry will be 
affected by this AD, that it will take approximately (1) 8 work hours 
per helicopter to replace the mast and 10 work hours per helicopter to 
replace the spline plate; (2) 2 work hours per helicopter to create the 
component history card or 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 will cost approximately 
$21,635 per mast and $5,675 per spline plate. Based on these figures, 
the total cost impact of the AD on U.S. operators is estimated to be 
$1,602,790 for the first year, and each subsequent year to be 
$1,573,390. These costs assume replacement of the mast and spline plate 
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 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.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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 
to read as follows:

AD 97-11-04  Bell Helicopter Textron Inc.: Amendment 39-10033. 
Docket No. 94-SW-20-AD.

    Applicability: Model 412 and Model 412EP helicopters with main 
rotor mast (mast), part number (P/N) 412-040-101-105, -109, -117, -
121, -125, -127, or -129, and main rotor spline plate (spline plate) 
P/N 412-010-167-105 or P/N 412-010-177-101, -105, -109, -113, or -
117, 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 (e) 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 within 100 hours time-in-service (TIS) 
after the effective date of this AD, unless accomplished previously.
    To prevent fatigue failure of the mast and spline plate, which 
could result in failure 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 
each affected mast and spline plate. Record the accumulated 
Retirement Index Number (RIN) on the mast and spline plate component 
history card(s) as follows:

[[Page 27497]]

    (1) If the numbers of takeoffs (at any gross weight) and 
external load lift events are known, and those numbers do not 
include any external load operation in which the load was picked up 
at a higher elevation and released at a lower elevation, and the 
difference in elevation between the pickup point and the release 
point was 200 feet or greater (high power lift event), increase the 
accumulated RIN by one for each takeoff and external load lift.
    (2) If the numbers of takeoffs (at any gross weight) and 
external load lifts are known, and the number of external load lifts 
includes a high power lift event, increase the accumulated RIN by 
two for each takeoff and two for each external load lift.
    (3) For each hour TIS for which the numbers of takeoffs and 
external load lifts are unknown, and the number of external load 
lifts does not include a high power lift event, increase the 
accumulated RIN by 10 for each hour TIS.
    (4) For each hour TIS for which the numbers of takeoffs and 
external load lifts are unknown, but the number of external load 
lifts does include a high power lift event, increase the accumulated 
RIN by 20 for each hour TIS.
    (5) For each hour TIS for which the numbers of takeoffs and 
external load lifts are unknown, and it is unknown whether the 
external load lifts include any high-power lift event, increase the 
accumulated RIN by 20 for each hour TIS.
    (b) After compliance with paragraph (a) of this AD, during each 
operation thereafter, maintain a count of each lift or takeoff 
performed and at the end of each day's operations, increase the 
accumulated RIN on the component history card as follows:
    (1) Increase the RIN by 1 for each takeoff.
    (2) Increase the RIN by 1 for each external load lift, or 
increase the RIN by 2 for each external load operation in which the 
load is picked up at a higher elevation and released at a lower 
elevation, and the difference in elevation between the pickup point 
and the release point is 200 feet or greater.
    (c) Retire the mast and spline plate in accordance with the 
following:
    (1) For the mast, P/N 412-040-101-105, -109, -117, or -127, used 
on the Model 412 helicopter upon reaching 10,000 hours TIS or 80,000 
maximum RIN, whichever occurs first.
    (2) For the mast, P/N 412-040-101-121, -125, or -129, used on 
the Model 412EP helicopter, upon reaching 10,000 hours TIS or 60,000 
maximum RIN, whichever occurs first.
    (3) For the spline plate, P/N 412-010-167-105 or P/N 412-010-
177-101, or -109, used on the Model 412 helicopter, at 10,000 hours 
TIS or 80,000 maximum RIN, whichever occurs first.
    (4) For the spline plate, P/N 412-010-167-105 or P/N 412-010-
177-101, -105, -113, or -117, used on the Model 412EP helicopter, at 
10,000 hours TIS or 60,000 maximum RIN, whichever occurs first.
    (d) For spline plate, P/N 412-010-167-105 or P/N 412-010-177-
101, -105, -113, or -117, installed on Model 412EP helicopters, at 
the next scheduled teardown inspection, beside the P/N on the side 
of the spline plate, vibro-etch ``412HP'' and annotate in the 
component history card or equivalent record ``412HP/EP only'' to 
reflect that this spline plate can only be installed on the Model 
412EP helicopter, and not on any other Model 412 helicopter. Retire 
the spline plates that have been vibro-etched with ``412HP'' on or 
before accumulating 10,000 hours TIS or 60,000 RIN, whichever occurs 
first.

    Note 2: Bell Helicopter Textron, Inc. Alert Service Bulletin No. 
412-94-81, Revision B, dated March 4, 1996, pertains to this 
subject.

    (e) 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 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.

    (f) 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.
    (g) This amendment becomes effective on June 24, 1997.

    Issued in Fort Worth, Texas, on May 9, 1997.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 97-13084 Filed 5-19-97; 8:45 am]
BILLING CODE 4910-13-U