E6-14291. Airworthiness Directives; MD Helicopters, Inc. Model MD900 Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment supersedes an existing airworthiness directive (AD) for MD Helicopters, Inc. (MDHI) Model MD900 helicopters, that currently requires reducing the life limit of certain Notar fan system tension-torsion (TT) straps. That existing AD also requires, at a specified time interval, removing each affected TT strap from the helicopter, doing a visual and X-ray inspection, and replacing any unairworthy part before further flight. This amendment requires the same actions as the existing AD, but also requires revising the life limit on the component history card or equivalent record and doing repetitive visual and X-ray inspections, and removes reporting requirements. This amendment is prompted by two in-flight TT strap failures. The actions specified by this AD are intended to prevent failure of a TT strap, loss of directional control, and subsequent loss of control of the helicopter.

DATES:

Effective October 3, 2006.

The incorporation by reference of MD Helicopters Service Bulletin SB900-095, dated November 3, 2004, was approved previously by the Director of the Federal Register as of December 7, 2004 (69 FR 67806, November 22, 2004).

ADDRESSES:

You may get the service information identified in this AD from MD Helicopters Inc., Attn: Customer Support Division, 4555 E. McDowell Rd., Mail Stop M615, Mesa, Arizona 85215-9734, telephone [phone], fax [phone], or on the web at http://www.mdhelicopters.com.

Examining the Docket

You may examine the docket that contains this AD, any comments, and other information on the Internet at http://dms.dot.gov, or at the Docket Management System (DMS), U.S. Department of Transportation, 400 Seventh Street, SW., Room PL-401, on the plaza level of the Nassif Building, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

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

SUPPLEMENTARY INFORMATION:

A proposal to amend 14 CFR part 39 by superseding AD 2004-23-15, Amendment 39-13870 (69 FR 67805, November 22, 2004), for MDHI Model MD900 helicopters, was published in the Federal Register on May 10, 2006 (71 FR 27212). The action proposed to require the following for MDHI Model MD900 helicopters with a TT strap, part number (P/N) 900R3442009-103, 900R6442009-103, 900R3442009-101, or 500N5311-5, installed:

• Before further flight, unless accomplished previously, for TT strap, P/N 900R3442009-103 and 900R6442009-103, reducing the life limit from 3,034 to 2,500 hours TIS and revising the life limit on the component history card or equivalent record;
• Within 10 hours TIS, unless accomplished previously, and then at intervals not to exceed 300 hours TIS, for any TT strap that has accumulated 1,190 or more hours TIS, doing a visual and X-ray inspection of each TT strap and replacing any unairworthy TT strap before further flight; and
• Before the TT strap accumulates 1,200 hours TIS, and then at intervals not to exceed 300 hours TIS, for any TT strap with less than 1,190 hours TIS, doing a visual and X-ray inspection of each strap and replacing any unairworthy TT strap before further flight.

At the time that we issued AD 2004-23-15, the cause of the TT strap failures was not known, and that AD was considered interim action. The actions required by this AD are also are interim actions, because the cause of the failures is still unknown and the investigation is ongoing. We will consider further rulemaking once our investigation is complete.

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. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed, with one change—contact information for the FAA has been added to paragraph (f) of the AD. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

The FAA estimates that this AD will affect 31 helicopters of U.S. registry, and the required actions will take approximately 7 work hours for each visual inspection and replacement at an average labor rate of $65 per work hour. Because you must remove the TT strap to inspect it, there is no additional labor cost for replacing the TT strap. It will also cost $100 for each X-ray inspection. Required parts will cost about $757 to replace each strap. Based on these figures, we estimate the total cost impact of this AD on U.S. operators to be $168,950 in the first year (assuming a total of 5 TT straps are replaced per helicopter and 3 visual inspections and 3 X-ray inspections are conducted the first year for each helicopter).

Regulatory Findings

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD 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.

For the reasons discussed above, I certify that the 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. 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.

We prepared an economic evaluation of the estimated costs to comply with this AD. See the DMS to examine the economic evaluation.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

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 removing Amendment 39-13870 ( 69 FR 67805, November 22, 2004), and by adding a new airworthiness directive (AD), Amendment 39-14739, to read as follows:

2006-18-01 MD Helicopters, Inc.: Amendment 39-14739. Docket No. FAA-2006-24631; Directorate Identifier 2005-SW-01-AD. Supersedes AD 2004-23-15, Amendment 39-13870, Docket No. FAA-2004-19613, Directorate Identifier 2004-SW-38-AD.

Applicability: Model MD900 helicopters, with a Notar fan system that has a tension-torsion (TT) strap, part number (P/N) 900R3442009-103, 900R6442009-103, 900R3442009-101, or 500N5311-5, installed, certificated in any category.

Compliance: Required as indicated.

To prevent failure of a TT strap in the Notar fan system, loss of directional control, and subsequent loss of control of the helicopter, accomplish the following:

(a) Before further flight, unless accomplished previously, for TT Straps, P/N 900R3442009-103 and 900R6442009-103, reduce the life limit from 3,034 to 2,500 hours time-in-service (TIS) and revise the life limit on the component history card or equivalent record to reflect this reduced retirement life.

(b) Within 10 hours TIS, unless accomplished previously, for any TT strap that has accumulated 1,190 or more hours TIS, and then at intervals not to exceed 300 hours TIS, remove the TT strap from the helicopter and do a visual and an X-ray inspection in accordance with the Inspection Instructions, paragraph 2.B.(1). through (5)., and Figures 1 and 2 of MD Helicopters Service Bulletin SB900-095, dated November 3, 2004 (SB). Replace any unairworthy TT strap before further flight.

(c) Before the TT strap accumulates 1,200 hours TIS, for any TT strap with less than 1,190 hours TIS, and then at intervals not to exceed 300 hours TIS, remove the TT strap from the helicopter and do a visual and an X-ray inspection in accordance with the Inspection Instructions, paragraph 2.B.(1). through (5)., and Figures 1 and 2 of the SB. Replace any unairworthy TT strap before further flight.

(d) The X-ray inspection of the TT strap must be performed by a Level II or higher X-ray technician who is qualified under the guidelines established by MIL-STD-410E, ATA Specification 105, AIA-NAS-410, or an FAA-accepted equivalent for qualification standards.

(e) This AD revises the Airworthiness Limitations section of the maintenance manual by reducing the life limit of the TT straps, P/N 900R3442009-103 and 900R6442009-103, from 3,034 hours TIS to 2,500 hours TIS. Additionally, this AD revises the Airworthiness Limitations section of the maintenance manual by adding repetitive inspection requirements at intervals not to exceed 300 hours TIS for TT straps, P/N 900R3442009-103, 900R6442009-103, 900R3442009-101, and 500N5311-5, that have 1,200 or more hours TIS until the TT strap reaches its retirement life.

(f) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Manager, Los Angeles Aircraft Certification, FAA, ATTN: Roger Durbin, Aviation Safety Engineer, Airframe Branch, 3960 Paramount Blvd., Lakewood, California 90712, telephone [phone], fax [phone], for information about previously approved alternative methods of compliance.

(g) The X-ray inspection shall be done in accordance with the specified portions of MD Helicopters Service Bulletin SB900-095, dated November 3, 2004. The incorporation by reference of that document was approved previously by the Director of the Federal Register, in accordance with 5 U. S.C. 552(a) and 1 CFR part 51, as of December 7, 2004 (69 FR 67806, November 22, 2004). Copies may be obtained from MD Helicopters Inc., Attn: Customer Support Division, 4555 E. McDowell Rd., Mail Stop M615, Mesa, Arizona 85215-9734, telephone [phone], fax [phone], or on the web at http://www.mdhelicopters.com. Copies may be inspected at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.

(h) This amendment becomes effective on October 3, 2006.

Issued in Fort Worth, Texas, on August 22, 2006.

Mark R. Schilling,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.