AD 2001-05-09

This amendment adopts a new airworthiness directive (AD) for Bell Helicopter Textron Canada (BHTC) Model 430 helicopters that requires modifying the electrical system. This amendment is prompted by the loss of electrical power due to design deficiencies discovered during single-pilot Instrument Flight Rules (IFR) flight testing. The actions specified by this AD are intended to prevent loss of electrical power and subsequent loss of control of the helicopter.

Final rule

2001-05-09 BELL HELICOPTER TEXTRON CANADA: Amendment 39-12146. Docket No. 2000-SW-22-AD.
Applicability: Model 430 helicopters, serial numbers 49002, 49004 through 49006, 49008 through 49016, 49018 through 49025, and 49027 through 49036, certificated in any category.

Note 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise 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 (b) 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 at the next 600-hour inspection or before further flight after May 1, 2001, whichever occurs first, unless accomplished previously.
To prevent loss of electrical power and subsequent loss of control of the helicopter, accomplish the following:

(a) Modify the electrical system in accordance with the Accomplishment Instructions, paragraphs 1 through 6, of Bell Helicopter Textron Alert Service Bulletin No. 430-99-10, dated December 16, 1999.

(b) 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, Regulations Group, 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, Regulations Group.

Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, ifany, may be obtained from the Regulations Group.

(c) 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.

(d) The modification shall be done in accordance with the Accomplishment Instructions, paragraphs 1 through 6, of Bell Helicopter Textron Alert Service Bulletin No. 430-99-10, dated December 16, 1999. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Bell Helicopter Textron, Inc., P.O. Box 482, Fort Worth, Texas 76101, telephone (817) 280-3391, fax (817) 280-6466. Copies may be inspected at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(e) This amendment becomes effective on April 24, 2001.

Note 3: The subject of this AD is addressed in Transport Canada, Canada, AD CF-2000-08, dated March 21, 2000.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD for BHTC Model 430 helicopters was published in the Federal Register on August 9, 2000 (65 FR 48645). That action proposed to require implementing the following electrical system changes in accordance with Alert Service Bulletin No. 430-99-10, dated December 16, 1999 (ASB):

o Modify the electrical bus distribution system to include emergency, essential, and nonessential busses. Relocate electrical system circuit breakers accordingly.

o Add a second redundant aircraft DC power supply with associated circuit breaker for each full authority digital engine control electronic control unit.

o Modify AC inverter switching logic to prevent inadvertent loss of AC power.

o Modify electrical bonding of the DC generator ground circuits by increasing the size of the hardware securing the ground shunt bus bar to the airframe structure.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. However, additional FAA engineering evaluation of the required modification was conducted after publication of the NPRM. That evaluation necessitated an extension of the compliance date from December 31, 2000 to May 1, 2001 to meet the intent of not grounding helicopters when this AD is effective. Except for that change, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed. The FAA has determined that changing the compliance date will neither increase the economic burden on any operator nor increase the scope of the AD.

The FAA estimates that 3 helicopters of U.S. registry will be affected by this AD, that it will take approximately 140 work hours per helicopter to accomplish the required actions, and that the average labor rate is $60 per work hour. The manufacturer states in the ASB that they will provide the 100 percent warranty credit for the parts and will allow a maximum warranty credit of $7700 for labor costs. Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $2100, assuming the stated credit for parts and labor.

The regulations adopted herein will not have a substantial direct effect 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, it is determined that this final rule does not have federalism implications under Executive Order 13132.

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, Incorporation by reference, 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.

39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive to read as follows: