DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39 [63 FR 36377 No. 128, 7/6/98]

[Docket No. 94-SW-23-AD]

Airworthiness Directives; Bell Helicopter Textron, Inc. Model 214B and 214B-1 Helicopters

ACTION: Supplemental notice of proposed rulemaking (SNPRM); reopening of comment period.

SUMMARY: This document revises an earlier proposed airworthiness directive (AD), applicable to Bell Helicopter Textron, Inc. (BHTI) Model 214B and 214B-1 helicopters, that would have established a mandatory retirement life of 15,000 high-power events for the pillow block bearing bolts (bearing bolts). That proposal was prompted by fatigue analyses and tests that show certain bearing bolts fail sooner than originally anticipated because of the unanticipated high number of lifts and takeoffs (torque events) performed with those bearing bolts in addition to the time-in-service (TIS) accrued under normal operating conditions. This action revises the proposed rule by proposing the creation of a component history card using a Retirement Index Number (RIN) system, establishment of a system for tracking increases to the accumulated RIN, and establishment of a maximum accumulated RIN for the bearing bolts. The actions specified by this proposed AD are intended to prevent fatigue failure of the bearing bolts, which could result in failure of the main rotor system and subsequent loss of control of the helicopter.

DATES: Comments must be received on or before September 4, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 94-SW-23-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.

FOR FURTHER INFORMATION CONTACT: Mr. Harry Edmiston, Aerospace Engineer, FAA, Rotorcraft Directorate, Rotorcraft Certification Office, Fort Worth, Texas 76193-0170, telephone (817) 222-5158, fax (817) 222-5961.

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. 94-SW-23-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. 94-SW-23-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

Discussion

	A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39), applicable to BHTI Model 214B and 214B-1 helicopters, was published in the Federal Register on May 3, 1993 (58 FR 35902; July 2, 1993). That NPRM would have required changing the method of calculating the retirement life for the bearing bolts, part number (P/N) 20-057-12-48D and P/N 20-057-12-50D, from flight hours to equivalent operating hours based on high-power events calculated using the number of takeoffs and external load lifts, or a maximum of 15,000 high power events, whichever occurred first. That NPRM was prompted by fatigue analyses and tests that show certain bearing bolts fail sooner than originally anticipated because of the unanticipated high number of lifts and takeoffs (torque events) performed with those bearing bolts in addition to the TIS accrued under normal operating conditions. That condition, if not corrected, could result in fatigue failure of the bearing bolts, which could result in failure of the main rotor system and subsequent loss of control of the helicopter.
	Since the issuance of that NPRM, BHTI has issued BHTI Information Letter GEN-94-54, dated April 15, 1994, Subject: Retirement Index Number (RIN) For Cycle Lifed Components, which introduces a different method of accounting for fatigue damage on components that have shortened service lives as a result of frequent torque events.
	Additionally, BHTI has issued BHTI Alert Service Bulletin (ASB) 214-94-54, dated November 7, 1994, which describes procedures for converting flight hours and total number of torque events into a RIN for the bearing bolts, P/N 20-057-12-48D.
	The FAA desires to implement a standardized system to account for the high power torque events and the retirement lives of these bearing bolts. Therefore, the FAA now proposes to require the RIN method of accounting for high power torque events. The proposed AD would require creation of a component history card using the RIN system; establishment of a system for tracking increases to the accumulated RIN; and establishment of a maximum accumulated RIN for the bearing bolts of 17,000 before they must be removed from service.
	Since this change expands the scope of the originally proposed rule, the FAA has determined that it is necessary to reopen the comment period to provide additional opportunity for public comment.
	The FAA estimates that 54 helicopters of U.S. registry would be affected by this proposed AD, and that it would take (1) 24 work hours per helicopter to replace the affected bearing bolts due to the new method of determining the retirement life; (2) 2 work hours per helicopter to create the component history card or equivalent record (record); and (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 $2,000 per helicopter. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $224,640 for the first year and $128,520 for each subsequent year. These costs assume replacement of the bearing bolts in the fleet the first year, creation and maintenance of the records for all the fleet; and replacement of one-half of the fleet's bolts, creation of the records for one-half of the fleet, and maintenance of the records for all the fleet each subsequent year.
	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 adding a new airworthiness directive (AD), to read as follows:

Bell Helicopter Company, Inc. (BHTI): Docket No. 94-SW-23-AD.

	Applicability: Model 214B and 214B-1 helicopters, 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 25 hours time-in-service (TIS), unless accomplished previously.
	To prevent fatigue failure of the pillow block bearing bolts (bearing bolts), part number (P/N) 20-057-12-48D or -50D, which could result in failure of the main rotor system and subsequent loss of control of the helicopter, accomplish the following:
	(a) Create a Retirement Index Number (RIN) component history card or an equivalent record for the bearing bolts, P/N 20-057-12-48D or -50D.
	(b) Calculate and record on the component history card the historical accumulated RIN for the bearing bolts as follows:
		(1) When the type of operation (internal or external load lift), actual flight hours, and number of external load lifts or takeoffs per hour are known, multiply the actual flight hours by the appropriate factor in the following table for external load lift operation:

Average No. of external load 
lift events per flight hour			Factor

0-2.00						6.8 
2.01-5.00					13.6 
5.01-16.00					27.2 
16.01-27.00					40.8 
Above 27.00					54.4

When the type of operation is internal load and no external lifting is involved, each hour of actual operating time is equal to 6.8 RIN.
 
		(2) When the actual flight hours on the bolts are known, but the type of operation (internal or external load lift) is unknown, multiply the actual flight hours by a factor of 40.8.
 		(3) When the actual flight hours on the bolts are unknown, assume 75 flight hours per month.
 		(4) When the flight hours on the bolts are assumed, but the type of operation (internal or external load lift) is known,
			(i) Multiply the number of flight hours assumed for internal load operations by a factor of 6.8.
			(ii) Multiply the number of flight hours assumed for external load operations by a factor of 40.8.
		(5) When the flight hours on the bolts are assumed and the type of operation (internal or external load lift) is unknown, multiply the assumed flight hours by a factor of 40.8.
	(c) After compliance with paragraphs (a) and (b) 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 bearing bolts 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.

	NOTE 2: Bell Helicopter Textron, Inc. Alert Service Bulletin 214-94-54, dated November 7, 1994, pertains to the subject of this AD.

	(d) Remove the bearing bolts from service on or before attaining an accumulated RIN of 17,000. The bearing bolts are no longer retired based upon flight hours. If any of the four bolts require replacement for any reason, then all four bolts must be replaced at that time. This AD revises the Airworthiness Limitations section of the maintenance manual by establishing a new retirement life for the bearing bolts of 17,000 RIN.
	(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.

	Issued in Fort Worth, Texas, on June 23, 1998.

Eric Bries, Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

FOR FURTHER INFORMATION CONTACT: Mr. Harry Edmiston, Aerospace Engineer, FAA, Rotorcraft Directorate, Rotorcraft Certification Office, Fort Worth, Texas 76193-0170, telephone (817) 222-5158, fax (817) 222-5961.