02-8595. Airworthiness Directives; MD Helicopters, Inc. Model 600N Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 2001-24-51, which was sent previously to all known U.S. owners and operators of MD Helicopters, Inc. (MDHI) Model 600N helicopters by individual letters. This AD requires, within 5 hours time-in-service (TIS), inspecting both upper tailboom attachments, nutplates and both angles for a crack or thread damage and repairing or replacing any cracked or damaged part before further flight. Also, this AD requires replacing the upper right-hand (RH) tailboom attachment bolt (bolt) with a new bolt, and if the upper RH bolt is broken, replacing the three remaining bolts with airworthy bolts before further flight. Adding a washer to each bolt and modifying both upper access covers are also required. Thereafter, at specified intervals, inspecting the upper tailboom attachments and repairing or replacing any cracked part before further flight is required. This AD is prompted by the discovery of a cracked bolt on a helicopter. The actions specified by this AD are intended to prevent failure of a tailboom attachment, loss of the tailboom, and subsequent loss of control of the helicopter.

DATES:

Effective April 29, 2002, to all persons except those persons to whom it was made immediately effective by Emergency AD 2001-24-51, issued on November 28, 2001, which contained the requirements of this amendment.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of April 29, 2002.

Comments for inclusion in the Rules Docket must be received on or before June 11, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2001-SW-57-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. You may also send comments electronically to the Rules Docket at the following address: [e-mail].

The applicable service information may be obtained from MD Helicopters Inc., Attn: Customer Support Division, 4555 E. McDowell Rd., Mail Stop M615-GO48, Mesa, Arizona 85215-9734, telephone [phone], fax [phone], or on the web at www.mdhelicopters.com. This information may be examined 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.

FOR FURTHER INFORMATION CONTACT:

Fred Guerin, Aviation Safety Engineer, FAA, Los Angeles Aircraft Certification Office, Airframe Branch, 3960 Paramount Blvd., Lakewood, California 90712, telephone [phone], fax [phone].

SUPPLEMENTARY INFORMATION:

On November 28, 2001 the FAA issued Emergency AD 2001-24-51 for MDHI Model 600N helicopters which requires, within 5 hours TIS, inspecting both upper tailboom attachments, nutplates and both angles for a crack or thread damage and repairing or replacing any cracked or damaged part before further flight. Also required is replacing the upper RH bolt with a new bolt, and if the upper RH bolt is broken, replacing the three remaining bolts with airworthy bolts before further flight. Adding a washer to each bolt and modifying both upper access covers are also required. Thereafter, at intervals not to exceed 25 hours TIS, inspecting the upper tailboom attachments and repairing or replacing any cracked part before further flight is required. That action was prompted by the discovery of a cracked bolt on a helicopter. Further inspection revealed cracking on bolts and attachments on several other helicopters. This condition, if not corrected, could result in failure of a tailboom attachment, loss of the tailboom, and subsequent loss of control of the helicopter.

The FAA has reviewed MD Helicopters, Inc. Service Bulletin SB600N-036, dated November 2, 2001 (SB). The SB describes procedures for inspecting the tailboom attach fittings and repairing damaged fittings. In addition to those procedures, the FAA has determined that if one bolt is broken, all four bolts must be replaced. Also, we have determined that a 25-hour TIS repetitive inspection of the tailboom attachments is required.

Since the unsafe condition described is likely to exist or develop on other MDHI Model 600N helicopters of the same type design, the FAA issued Emergency AD 2001-24-51 to prevent failure of a tailboom attachment, loss of the tailboom, and subsequent loss of control of the helicopter. The AD requires the following:

• Within 5 hours TIS:
• Remove the tailboom fairing, tailboom, and both upper tailboom attachment access covers.
• Using a light and a 10× or higher magnifying glass, inspect for a crack or damage:
• Both upper tailboom attachments and nutplates. If a crack or thread damage is found, replace any cracked or damaged attachments or nutplates with an airworthy part before further flight.
• Both angles. If a crack is found on the RH angle, before further flight, install a new clip. If a crack is found on the left-hand angle, before further flight, replace or repair the angle.
• Replace the upper RH tailboom attachment bolt with a new bolt. If the upper RH bolt is found broken, before further flight, also replace the three remaining bolts.
• Add a washer to each bolt.
• Modify both upper access covers.
• At intervals not to exceed 25 hours TIS, using a borescope, through the hole in each upper access cover, inspect the upper tailboom attachments for a crack. Repair or replace any cracked part with an airworthy part before further flight.

The actions must be accomplished in accordance with the SB described previously. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the structural integrity and controllability of the helicopter. Therefore, the previously stated actions are required within 5 hours TIS, and thereafter at the specified time intervals, and this AD must be issued immediately.

Since it was found that immediate corrective action was required, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest, and good cause existed to make the AD effective immediately by individual letters issued on November 28, 2001 to all known U.S. owners and operators of MDHI Model 600N helicopters. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to 14 CFR 39.13 to make it effective to all persons.

The FAA estimates that 33 helicopters of U.S. registry will be affected by this AD. It will take approximately 2 work hours per helicopter to perform the inspections, 8 work hours per helicopter to replace the bolts, if necessary, and 20 work hours to repair an angle, if necessary. The average labor rate is $60 per work hour. Required parts will cost $50 for each inspection, $200 to replace the bolts on each helicopter, and $100 to repair an angle. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $41,050 ($28,050 to inspect and replace the bolts on each helicopter and $13,000 to repair 10 helicopters).

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 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 mailed 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. 2001-SW-57-AD.” The postcard will be date stamped and returned to the commenter.

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.

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
• 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:

2001-24-51 MD Helicopters, Inc.: Amendment 39-12706. Docket No. 2001-SW-57-AD.

Applicability: Model 600N helicopters, serial numbers with a prefix “RN” and 003 through 063, 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 (c) 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 a tailboom attachment, loss of the tailboom, and subsequent loss of control of the helicopter, accomplish the following:

(a) Within 5 hours time-in-service (TIS):

(1) Remove the tailboom fairing and tailboom. Remove both upper tailboom attachment access covers in accordance with the Accomplishment Instructions, paragraph 2.B.(2) of MD Helicopters, Inc. (MDHI) Service Bulletin SB600N-036, dated November 2, 2001 (SB).

Note 2:

MDHI CSP-HMI-2, Section 53-40-30, pertains to the subject of this AD.

(2) Using a light and a 10x or higher magnifying glass:

(i) Inspect the right and left upper tailboom attachments, part number (P/N) 500N3422 and 500N3422-3, respectively, for a crack as shown in Figure 1 of the SB. If a crack is found, replace any cracked attachment fitting with an airworthy attachment fitting before further flight.

(ii) Inspect both upper tailboom attachment nutplates for thread damage or a crack. Replace any damaged or cracked nutplate with an airworthy nutplate before further flight.

(iii) Inspect both angles for a crack. If a crack is found on a right-hand angle, P/N 500N3429-6, before further flight, install a new clip in accordance with the Accomplishment Instructions, paragraph 2.B.(5)(c) of the SB. If a crack is found on the left-hand angle, P/N 500N3429-7, before further flight, replace the angle with an airworthy angle, or repair the angle in accordance with FAA-approved procedures.

(3) Replace the upper right-hand (pilot side) tailboom attachment bolt (bolt) with a new bolt.

(4) If the removed upper pilot-side bolt is found broken, replace the remaining three bolts with airworthy bolts before further flight.

(5) Add one washer, P/N AN960C516 (NAS1149C0563R) or AN960C616 (NAS1149C0663R), as appropriate, to each tailboom bolt between the tailboom and the NAS1587 countersunk washer. A minimum of two threads must extend past the nutplate.

(6) Modify both access covers in accordance with the Accomplishment Instructions, paragraph 2.B.(6), of the SB.

(b) At intervals not to exceed 25 hours TIS, using a borescope, through the hole in each upper access cover, inspect the right and left upper tailboom attachments, nutplates, and angles for a crack. If a crack is found, replace or repair any cracked part with an airworthy part in accordance with the requirements of this AD before further flight.

(c) 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 (LAACO), FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, LAACO.

Note 3:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the LAACO.

(d) Special flight permits may be issued in accordance with 14 CFR 21.197 and 21.199 to operate the helicopter to a location where the requirements of this AD can be accomplished.

(e) The removal of the upper tailboom attachment access covers, inspection of the tailboom attachments, installation of a new clip, and modification of the access covers shall be accomplished in accordance with the Accomplishment Instructions, paragraphs 2.B.(2), 2.B.(5)(c), 2.B.(6), and Figure 1, of MD Helicopters, Inc. Service Bulletin SB600N-036, dated November 2, 2001. 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 MD Helicopters Inc., Attn: Customer Support Division, 4555 E. McDowell Rd., Mail Stop M615-GO48, Mesa, Arizona 85215-9734, telephone [phone], fax [phone], or on the web at www.mdhelicopters.com. 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.

(f) This amendment becomes effective on April 29, 2002, to all persons except those persons to whom it was made immediately effective by Emergency AD 2001-24-51, issued November 28, 2001, which contained the requirements of this amendment.

Issued in Fort Worth, Texas, on April 2, 2002.

Eric Bries,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.