AD 2013-05-16

We are adopting a new airworthiness directive (AD) for MD Helicopters, Inc. (MDHI) Model 369D, 369E, 369F, and 369FF helicopters with certain serial-numbered tailboom assemblies. This AD requires measuring the distance between aft longeron rivets and the outboard edge of frame rings. If the distance is too short to ensure a safe flight, the AD requires installing a doubler. This AD was prompted by the discovery of short-edge margin conditions on two tailboom assemblies. The actions are intended to detect a short-edge margin condition, prevent failure of the tailboom and loss of control of the helicopter.

Final rule.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0 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]

0 2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive (AD):

2013-05-16 Hughes Helicopters, Inc., and McDonnell Douglas Helicopter Systems (Type Certificate currently held by MD Helicopters, Inc., (MDHI): Amendment 39-17388; Docket No. FAA-2012- 0890; Directorate Identifier 2011-SW-019-AD.

(a) Applicability

This AD applies to Model 369D, E, F, and FF helicopters with tailboom assembly, part number 369D23500-505, -507, -511, or -513 with a serial number prefix of ``7604'' and -0001 through -0003, - 0006 through -0047, -0049 through -0082, or -0084 through -0113, installed, certificated in any category.(b) Unsafe Condition

This AD defines the unsafe condition as too short an edge distance from an aft longeron rivet to the edge of a tailboom frame ring, which could result in failure of the tailboom and subsequent loss of control of the helicopter.

(c) Effective Date

This AD becomes effective April 30, 2013.

(d) Compliance

You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.

(e) Required Actions

(1) Within 6 months or 100 hours time-in-service, whichever occurs first, measure the distance from the aft face of the station 209.78 frame ring to the center of rivet No. 1 and rivet No. 2 at the four locations where the frame ring attaches to the tailboom longeron as depicted in Figure 2 of MD Helicopters Service Bulletin (SB) No. SB369D-207, SB369E-102, and SB369F-087, dated July 20, 2010. SB369D-207 applies to Model 369D helicopters; SB369E-102 applies to Model 369E helicopters; and SB369F-087 applies to Model 369F and FF helicopters.
(2) If either the No. 1 or No. 2 aft rivet at a frame-ring-to- tailboom-longeron location is more than 0.50 inches (12.7 millimeters) from the aft face of the station 209.78 frame ring, before further flight, modify that location by fabricating and installing a doubler over the location as depicted in Figures 3 and 4 and by following the Accomplishment Instructions, paragraph 2.C., of the SB for your model helicopter.

(f) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Los Angeles Aircraft Certification Office, FAA, may approve AMOCs for this AD. Send your proposal to: John Cecil, Aerospace Engineer, FAA, Los Angeles Certification Office, Airframe Branch, 3960 Paramount Blvd., Lakewood, California 90712-4137, telephone (562) 627-5228, fax (562) 627-5210, email john.cecil@faa.gov.
(2) For operations conducted under a 14 CFR part 119 operating certificate or under14 CFR part 91, subpart K, we suggest that you notify your principal inspector, or lacking a principal inspector, the manager of the local flight standards district office or certificate holding district office before operating any aircraft complying with this AD through an AMOC.

(g) Subject

Joint Aircraft Service Component (JASC) Code 5302: Rotorcraft Tailboom.

(h) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise.
(i) MD Helicopters, Inc., Service Bulletin (SB) No. SB369D-207, dated July 20, 2010.
(ii) MD Helicopters, Inc., SB No. SB369E-102, dated July 20, 2010.
(iii) MD Helicopters, Inc., SB No. SB369F-087, dated July 20, 2010.

Note 1 to paragraph (h)(2) of this AD: MD Helicopters, Inc., issued one service bulletin with three numbers, SB369D-207, SB369E- 102, and SB369F-087, all dated July 20, 2010.

(3) You may view this service information at FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. For information on the availability of this material at the FAA, call (817) 222-5110.
(4) You may view this service information that is incorporated by reference 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/cfr/ibr-locations.html.

Discussion

On August 29, 2012, at 77 FR 52264, the Federal Register published our notice of proposed rulemaking (NPRM), which proposed to amend 14 CFR part 39 to include an AD that would apply to the specified MDHI helicopters with certain serial-numbered tailboom assemblies installed. Customers returned two tailboom assemblies to the manufacturer that contained an improperly installed frame ring at station 209.78. The frame rings were installed with too short a distance between an aft longeron rivet and the outboard edge of the frame ring. This is known as a short-edge margin condition. That NPRM proposed to require that within 6 months or 100 hours time-in-service, whichever occurs first, measuring the distance from the aft face of the station 209.78 frame ring to the center of the rivet No. 1 and rivet No. 2 at the four locations where the frame ring attaches to the tailboom longeron. If either the No. 1 or No. 2 aft rivet at a frame-ring-to-tailboom- longeron location is more than 0.50 inches (12.7 millimeters) from the aft face of the station 209.78 frame ring, before further flight, the AD proposed to modify that location by fabricating and installing a doubler over the location. The proposed requirements were intended to prevent failure of the tailboom and loss of control of the helicopter.

Comments

We gave the public the opportunity to participate in developing this AD, but we received no comments on the NPRM (77 FR 52264, August 29, 2012).

FAA's Determination

We have reviewed the relevant information and determined that an unsafe condition exists and is likely to exist or develop on other products of these same type designs and that air safety and the public interest require adopting the AD requirements as proposed.

Related Service Information

MDHI has issued one Service Bulletin (SB), dated July 20, 2010, with three numbers: SB No. SB369D-207 for the Model 369D helicopters, SB No. SB369E-102 for the Model 369E helicopters, and SB No. SB369F-087 for the Model 369F and 369FF helicopters. The MDHI SB describes procedures for measuring the distance from the aft face of the station 209.78 canted frame ring to the center of the No. 1 and No. 2 aft rivet locations on each of the four longerons spaced 90 degrees apart around the frame ring. If the short-edge margin condition exists, the SB specifies modifying the tailboom by installing a repair doubler at each affected location.

Costs of Compliance

We estimate that this AD will affect 109 helicopters of U.S. Registry and that operators will spend $340 for 4 work-hours at an average labor cost of $85 per work hour to access and measure for a short-edge margin condition for a cost of $37,060 for the U.S. fleet.
The on-condition costs for installing the doubler are not included in our cost

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estimate because we have no way of determining the number of aircraft that might need a doubler. If they do, about 8 work-hours in labor and $19 in parts are required for a total cost of $699.

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.

Regulatory Findings

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 this AD:
(1) Is not a ``significant regulatory action'' under Executive Order 12866;
(2) Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
(3) Will not affect intrastate aviation in Alaska to the extent that it justifies making a regulatory distinction; and
(4) 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 and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.