AD 99-09-20

This amendment adopts a new airworthiness directive (AD) that is applicable to BHTC Model 222, 222B, and 222U helicopters. This action requires initial and repetitive visual inspections and verification of the torque of the bolts on the main rotor hub. This amendment is prompted by a report of fatigue cracks around the bolt holes of the main rotor pitch horn (pitch horn) and a cracked main rotor flapping bearing assembly (flapping bearing assembly) on a BHTC Model 222 helicopter. This condition, if not corrected, could result in fretting-induced fatigue cracking of the flapping bearing assembly and around the bolt holes of the pitch horn, loss of the rotor system, and subsequent loss of control of the helicopter.

Final rule; request for comments

99-09-20 BELL HELICOPTER TEXTRON CANADA: Amendment 39-11153. Docket No. 98-SW-49-AD.

Applicability: Model 222 helicopters, serial numbers (S/N) 47006 through 47089, Model 222B helicopters, S/N's 47131 through 47156, and Model 222U helicopters, S/N's 47501 through 47574, 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 as indicated, unless accomplished previously.

To prevent fretting induced fatigue cracking of the main rotor flapping bearing assembly (flapping bearing assembly) and around the bolt holes of the main rotor pitch horn (pitch horn), loss of the rotor system, and subsequent loss of control of the helicopter, accomplish the following:

(a) Within 10 hours time-in-service (TIS), and thereafter at intervals not to exceed 150 hours TIS:

(1) Perform a visual inspection of the main rotor hub for fretting between the pitch horn and main rotor grip tangs (grip tangs) and between the flapping bearing assembly and the main rotor yoke assembly. If fretting is found on any part, replace it with an airworthy part.

(2) Verify the torque of the main rotor grip retaining bolts and the flapping bearing assembly bolts in the tightening direction, minimum 100 foot-pounds. If 100 foot-pounds torque is reached without movement of the bolts, torque bolts to 125 foot-pounds.

(3) If any bolt moves before 100 foot-pounds torque is reached, remove the pitch horn or the flapping bearing assembly, as applicable, from the main rotor hub assembly for further inspection. Inspect the pitch horn or flapping bearing assembly, as applicable, and all faying surfaces of the pitch horn, flapping bearing assembly, buffers, main rotor yoke assembly, and the grip tangs for fretting. If fretting is found on any part, replace it with an airworthy part.

(4) Apply corrosion preventive compound to the exposed portions of the bolts and nuts.

NOTE 2: Bell Helicopter Textron Alert Service Bulletin Nos. 222-98-81 and 222U-98-52, both dated April 23, 1998, pertain to the subject of this AD.

(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, Rotorcraft Certification Office, FAA, Rotorcraft Directorate. 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.

(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.

NOTE 4: The subject of this AD is addressed in Transport Canada (Canada) AD CF-98-16, dated July 15, 1998.

(d) This amendment becomes effective on May 14, 1999.

Transport Canada, which is the airworthiness authority for Canada, has notified the FAA that an unsafe condition may exist on BHTC Model 222, 222B, and 222U helicopters. Transport Canada advises that fatigue cracks at the bolt holes of the pitch horn and in the flapping bearing assembly can lead to loss of control of the helicopter.

BHTC issued Alert Service Bulletin Nos. 222-98-81 and 222U-98-52, both dated April 23, 1998 (ASB), which specify inspecting the main rotor hub in the areas between the pitch horn and main rotor grip tangs (grip tangs) and between the flapping bearing assembly and the main rotor yoke assembly for fretting. The ASB s also specify torque verification procedures for the main rotor grip retaining bolts and the flapping bearing assembly. Transport Canada classified these ASB s as mandatory and issued Transport Canada AD CF-98-16, dated July 15, 1998, in order to assure the continued airworthiness of these helicopters in Canada.

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 these type designs that are certificated for operation in the United States.

The FAA estimates that 88 helicopters will be affected by this proposed AD, that it will take approximately 1 work hour to accomplish the inspection and retorque of bolts, if necessary, 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 $15,840 per year, assuming three inspections and retorques per year and assuming that no parts will need to be replaced.

Since an unsafe condition has been identified that is likely to exist or develop on other BHTC Model 222, 222B, and 222U helicopters of the same type design registered in the United States, this AD is being issued to prevent fretting induced fatigue cracking of the flapping bearing assembly and around the bolt holes of the pitch horn, loss of the rotor system, and subsequent loss of control of the helicopter. This AD requires recurring inspections of the main rotor hub in the areas between the pitch horn and grip tangs and between the flapping bearing assembly and the main rotor yoke assembly for fretting. If fretting is found on any part, replacing that part with an airworthy part is required. This AD also requires verifying the torque on the main rotor grip retaining bolts and the flapping bearing assembly retaining bolts. The short compliance time involved is required becausethe previously described critical unsafe condition can adversely affect the controllability of the helicopter. Therefore, a visual inspection of the main rotor hub between the pitch horn and grip tangs and the flapping bearing assembly and the main rotor yoke assembly for fretting is required. A torque check of the main rotor grip retaining bolts and the flapping bearing assembly retaining bolts is also required. These actions are required within 10 hours TIS and this AD must be issued immediately.

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

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 thatsummarizes 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. 98-SW-49-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.

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