AD 94-26-10 ACTIVE

This amendment supersedes an existing airworthiness directive (AD), applicable to Robinson Helicopter Company (RHC) Model R44 series helicopters, that currently requires removal and replacement of specific parts of the cyclic control system. This amendment requires the same removal and replacement of specific parts of the cyclic control system, corrects a replacement part number, and changes the applicability to cover certain serial-numbered helicopters. This amendment is prompted by the need to correct the existing AD by changing the applicability to include additional serial-numbered helicopters and to correct a replacement part number that was incorrectly stated in the existing AD. The actions specified by this AD are intended to prevent failure of the cyclic control system and subsequent loss of control of the helicopter.

Final rule; request for comments

94-26-10 ROBINSON HELICOPTER COMPANY: Amendment 39-9105. Docket No. 94-SW-18-AD. Supersedes AD 94-17-18, Amendment 39-9013.

Applicability: Model R44 series helicopters with serial numbers (S/N) less than but not including S/N 0017, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the cyclic control system and subsequent loss of control of the helicopter, accomplish the following:

(a) Before further flight, remove the following cyclic control system parts and replace them with the corresponding replacement parts in accordance with the applicable maintenance manual:

Remove Part Numbers: Replace With Part Numbers:

Remove Part Numbers:
Replace With Part Numbers:
A205-3
A205-5 Revision J or subsequent FAA-
approved revisions.
C175-1
C175-2 Revision H or subsequent FAA-
approved revisions.
C176-1
C176-2 Revision B or subsequent FAA-
approved revisions.
C177-1
C177-2 Revision F or subsequent FAA-
approved revisions.
C319-1
C319-3 Revision I or subsequent FAA-
approved revisions.
C320-1
C320-1 Revision L or subsequent FAA-
approved revisions.
C958-4
C958-5 Revision E or subsequent FAA-
approved revisions.
A101-4
D173-1 Revision A or subsequent FAA-
approved revisions.
C338-1
C338-4 Revision C or subsequent FAA-
approved revisions.
A211-2
A211-3 Revision I or subsequent FAA-
approved revisions.
A137-1
A137-2 Revision C or subsequent FAA-
approved revisions.

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used when approved by the Manager, Los Angeles Aircraft Certification Office. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Los Angeles Aircraft Certification Office.

NOTE: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles Aircraft Certification Office.

(c) Special flight permits will not be issued.

(d) This amendment becomes effective on January 11, 1995.

On August 18, 1994, the FAA issued AD 94-17-18, Amendment 39-9013 (59 FR 43726, August 25, 1994), to require immediate removal and replacement of specific parts of the cyclic control system in accordance with the applicable maintenance manual. That action was prompted by an accident involving an RHC Model R44 series helicopter. The National Transportation Safety Board (NTSB) determined the probable cause for the accident was fatigue failure of the cyclic stick assembly, a part of the cyclic control system. The pilot uses the cyclic control system to control the flight attitude of the helicopter. If the cyclic control system fails, the pilot loses the ability to make cyclic control inputs to the main rotor system. After reviewing the NTSB report, the FAA has determined that certain parts of the same design as those installed on the accident helicopter need to be replaced before further flight. That condition, if not corrected, could result in failure of the cyclic control system and subsequent loss of control of the helicopter.

Since the issuance of that AD, the FAA has become aware of an error in the AD. One of the cyclic control system replacement part numbers was incorrectly stated as C211-3. That part number should have been part number A211-3. Additionally, that AD should have been applicable to RHC Model R44 series helicopters, with serial numbers (S/N) less than but not including S/N 0017, since the manufacturing records indicate the design changes required by that AD were incorporated by RHC into the RHC Model R44 production line, beginning with helicopter S/N 0017. Upon review, the FAA has determined that the original cyclic control system design meets existing FAA design standards, but has limited damage tolerance characteristics and does not display slow crack growth properties. When damaged or flawed, the cyclic stick assembly can fail due to fatigue prior to its retirement time of 4,000 hours time-in-service.

Since an unsafe condition has been identified that is likely to exist or develop on other RHC Model R44 series helicopters of the same type design, this AD supersedes AD 94-17-18 and is being issued to prevent failure of the cyclic control system and subsequent loss of control of the helicopter. This AD requires removal and replacement of certain parts of the cyclic control system of the affected helicopters as well as changes the applicability of this AD to include certain serial- numbered helicopters. The actions are required to be accomplished in accordance with the applicable maintenance manual. Due to the critical need to (1) ensure the integrity of the cyclic control system, (2) comply with the requirements of this AD before further flight, and (3) require replacement of certain parts on certain serial-numbered helicopters, this rule must be issued immediately to correct an unsafe condition in the affected helicopters.
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 that summarizes 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. 94-SW-18-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. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.

39.13 - [Amended]
2. Section 39.13 is amended by removing Amendment 39-9013 (59 FR 43726, August 25, 1994), and by adding a new airworthiness directive (AD), Amendment 39-9105, to read as follows:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Assistant Chief Counsel, Attention: Rules Docket No. 94-SW-18-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

Ms. Lirio Liu, Aerospace Engineer, Los Angeles Aircraft Certification Office, FAA, ANM-123L, Transport Airplane Directorate, 3960 Paramount Blvd., Lakewood, California 90712, telephone (310) 627-5229, fax (310) 627-5210.