Airworthiness directives: McDonnell Douglas,

[Federal Register: March 23, 1999 (Volume 64, Number 55)]

[Proposed Rules]

[Page 13936-13938]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr23mr99-21]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-SW-16-AD]

Airworthiness Directives; McDonnell Douglas Helicopter Systems Model 600N Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to McDonnell Douglas Helicopter Systems (MDHS) Model 600N helicopters. This proposal would require applying serial numbers to several life-limited components related to pitch control and removing and replacing the components according to new life-limits. This proposal is prompted by fatigue tests that indicate a need for shorter service lives for these components. The actions specified by the proposed AD are intended to prevent failure of the collective pitch control tubes, collective stick housings, and collective pitch tube assemblies, which can cause loss of collective pitch control, and subsequent loss of control of the helicopter.

DATES: Comments must be received by May 24, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 98-SW-16-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.

The service information referenced in the proposed rule may be obtained from McDonnell Douglas Helicopter Systems, Technical Publications, Bldg. 530/B11, 5000 E. McDowell Road, Mesa, Arizona 85205-9797. This information may be examined at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas.

FOR FURTHER INFORMATION CONTACT: Frederick A. Guerin, Aerospace Engineer, Airframe Branch, Los Angeles Aircraft Certification Office, 3960 Paramount Blvd., Lakewood, California 90712, telephone (562) 627- 5232, fax (562) 627-5210.

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

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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 filedin 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. 98-SW-16-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. 98-SW-16-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

Discussion

This document proposes the adoption of a new AD that is applicable to MDHS Model 600N helicopters. This proposal would require three actions: (1) applying serial numbers to the collective pitch control tubes, part number's (P/N's) 369A7348 and 369H7809, and collective stick housings, P/N's 369A7347 and 369A7820; (2) adding the co-pilot collective pitch control tube, P/N 369A7809, to the Airworthiness Limitations section, Component Mandatory Replacement Schedule (CMRS), of the maintenance manual; and (3) reducing the service lives from those stated in the Airworthiness Limitations section, CMRS, of the pilot collective pitch control tube, P/N 369A7348, collective stick housings, P/N's 369A7347, 369A7820, and 369H7837, and collective pitch tube assemblies, P/N's 369H7354-3 and 369H7838-3. The following table shows the current life-limits and the proposed life-limits.

Proposed life- limit (hours Current life-limit (hours P/N

Component

time-in-

time-in-service) service)

369A7347........................... Housing, collective stick......

450 Unlimited 369A7348........................... Tube, collective pitch control.

400 Unlimited 369H7354-3......................... Tube assembly, collective pitch

600 1,500 (pilot). 369A7809........................... Tube, collective pitch (co-

1,800 Not Determined pilot). 369A7820........................... Housing, collective stick......

450 Unlimited 369H7837........................... Housing, collective stick......

450 Unlimited 369H7838-3......................... Tube assembly, collective pitch

1,000 1,500 (co-pilot).

This proposal is prompted by fatigue tests that indicate a need for shorter service lives for these components. The actions specified by the proposed AD are intended to prevent failure of the collective pitch control tubes, collective stick housings, and collective pitch tube assemblies, which can cause loss of collective pitch control, and subsequent loss of control of the helicopter.

The FAA has reviewed McDonnell Douglas Helicopter Systems Service Bulletin SB600N-009, dated February 24, 1998, that lists the service numbers to be applied to the four components for the listed aircraft serial numbers.

Since an unsafe condition has been identified that is likely to exist or develop on other MDHS Model 600N helicopters of the same type design, the proposed AD would require applying serial numbers to several life-limited components related to pitch control and removing and replacing several components according to new life-limits. The actions would be required to be accomplished in accordance with the service bulletin described previously.

The FAA estimates that 16 helicopters of U.S. registry would be affected by this proposed AD, that it would take approximately 0.5 work hour per helicopter to apply the serial numbers, and that the average labor rate is $60 per work hour. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $480.

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 to read as follows:

   McDonnell Douglas Helicopter Systems: Docket No. 98-SW-16-AD.

   Applicability: Model 600N helicopters, certificated in any category.

   Note 1: This AD applies to each helicopter identified in the preceding applicability

   [[Page 13938]]

   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 (e) 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 failure of the collective pitch control tubes, collective stick housings, and collective pitch tube assemblies, loss of collective pitch control, and subsequent loss of control of the helicopter, accomplish the following:

   (a) On or before reaching 400 hours time-in-service (TIS), apply the serial number (S/N) listed in McDonnell Douglas Helicopter System Service Bulletin No. 600N-009, dated February 24, 1998 (SB), to the two collective stick housings, P/N's 369A7347 and 369A7820; the pilot collective pitch control tube, P/N 369A7348; and the co- pilot collective pitch control tube, P/N 369A7809, in the most visible spot for the specified aircraft S/N.

   (b) Remove and replace the following flight control components according to the stated life-limits:

   Life-Limit P/N

   Component

   (hours TIS)

   1369A7347.................... Housing, collective stick

   450 369A7348..................... Tube, collective pitch

   400 control (pilot). 369H7354-3................... Tube assembly, collective

   600 pitch (pilot). 369A7809..................... Tube, collective pitch

   1,800 control (co-pilot). 369A7820..................... Housing, collective stick

   450 369H7837..................... Housing, collective stick

   450 369H7838-3................... Tube assembly, collective

   1,000 pitch (co-pilot).

   (c) Create a component history card or equivalent record in the helicopter log and record the helicopter TIS at installation for each of the components listed in paragraph (b) of this AD.

   (d) This AD revises the Airworthiness Limitations Section of the maintenance manual by reducing the life-limits of the pilot collective pitch control tube, the collective stick housings, and the collective pitch tube assemblies, and adding the co-pilot collective pitch control tube to the Airworthiness Limitations section, Component Mandatory Replacement Schedule.

   (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, Los Angeles Aircraft Certification Office, FAA. 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 2: 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.

   (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 March 16, 1999. Eric Bries, Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

   [FR Doc. 99-7025Filed3-22-99; 8:45 am]

   BILLING CODE 4910-13-U