# AD 2019-05-04: Main Rotor Blade - Type: Airworthiness directive - Status: Current - Products: MD Helicopters 369A, 369D, 369E, 369FF, 369H, 369HE, 369HM, 369HS, 500N and 600N - Effective: April 17, 2019 - Published: March 13, 2019, 84 FR 8959–8961 - Issued: February 28, 2019 - Issued as: Final rule - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Rotorcraft - Amendment: 39-19586 - Docket: FAA-2018-0991 (https://www.regulations.gov/docket/FAA-2018-0991) - Registered aircraft: 673 may be affected, by airframe or engine model (OpenAirDocs) - Official PDF: https://openairdocs.org/files/sha256/33/e4/33e456fa1591f1fe66817740c7b70ee395a77a60142d168f4d24f134992204dc (from https://www.govinfo.gov/content/pkg/FR-2019-03-13/pdf/2019-04528.pdf) - Federal Register: https://www.federalregister.gov/documents/2019/03/13/2019-04528/airworthiness-directives-md-helicopters-inc-mdhi-helicopters - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/0BF7ECB8C344DC77862583BC004B930D.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/2019-05-04 ## Summary We are adopting a new airworthiness directive (AD) for MDHI Model 369A, 369D, 369E, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters. This AD requires inspecting each main rotor blade (MRB) for a crack. This AD was prompted by reports of cracked MRBs. The actions of this AD are intended to address an unsafe condition on these helicopters. ## The airworthiness directive 1. The authority citation for part 39 continues to read as follows: 2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD): 2019-05-04 MD Helicopters, Inc.: Amendment 39-19586; Docket No. FAA-2018-0991; Product Identifier 2017-SW-050-AD. ### (a) Applicability This AD applies to MD Helicopters, Inc., Model 369A, 369D, 369E, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters, certificated in any category, with a main rotor blade (MRB) part number 369A1100, 369D21100, 369D21102, 369D21120, 369D21121, 369D21123, 500P2100, or 500P2300, all dash numbers, installed. ### (b) Unsafe Condition This AD defines the unsafe condition as a crack in an MRB. This condition could result in failure of the MRB and subsequent loss of control of the helicopter. ### (c) Effective Date This AD becomes effective April 17, 2019. ### (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 Within 25 hours time-in-service, and thereafter at each 100-hour inspection or annual inspection, whichever occurs first: (1) Using a 10X or higher power magnifying glass and a light, inspect each MRB trim tab end at the trailing edge corner where the trim tab and MRB meet for a crack. If there is a crack, before further flight, replace the MRB. (2) Using a 10X or higher power magnifying glass and a light, inspect the top and bottom surface of each MRB adjacent to the inboard trim tab corner for a crack, from the trailing edge towards the leading edge. If there is a crack, before further flight, replace the MRB. ### (f) Alternative Methods of Compliance (AMOCs) (1) The Manager, Los Angeles ACO Branch, FAA, may approve AMOCs for this AD. Send your proposal to: Galib Abumeri, Aviation Safety Engineer, Los Angeles ACO Branch, Compliance & Airworthiness Division, FAA, 3960 Paramount Blvd., Lakewood, CA 90712; telephone (562) 627-5374; email 9-ANM-LAACO-AMOC-REQUESTS@faa.gov. (2) For operations conducted under a 14 CFR part 119 operating certificate or under 14 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) Additional Information (1) Helicopter Technology Company, LLC, Mandatory Service Bulletin Notice No. 2100-9, dated May 25, 2017, which is not incorporated by reference, contains additional information about the subject of this AD. For Helicopter Technology Company, LLC, service information identified in this AD, contact Helicopter Technology Company, LLC, 12902 South Broadway, Los Angeles, CA 90061; telephone (310) 523-2750; or at www.helicoptertech.com. (2) MD Helicopters Service Bulletin No. SB369D-221, SB369E-119, SB369F-106, SB369H-257, SB500N-057, and SB600N-069, each dated April 2, 2018, which are not incorporated by reference, contain additional information about the subject of this AD. For MD Helicopters service information identified in this AD, contact MD Helicopters, Inc., Attn: Customer Support Division, 4555 E. McDowell Rd., Mail Stop M615, Mesa, AZ 85215-9734; telephone 1-800-388-3378; fax 480-346-6813; or at http://www.mdhelicopters.com. (3) You may review a copy of this service information at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy, Room 6N-321, Fort Worth, TX 76177. ### (h) Subject Joint Aircraft Service Component (JASC) Code: 6210, Main Rotor Blade. ## Rule preamble ### Dates This AD is effective April 17, 2019. ### Addresses For Helicopter Technology Company, LLC, service information identified in this final rule, contact Helicopter Technology Company, LLC, 12902 South Broadway, Los Angeles, CA 90061; telephone (310) 523-2750; or at www.helicoptertech.com. For MD Helicopters service information identified in this final rule, contact MD Helicopters, Inc., Attn: Customer Support Division, 4555 E. McDowell Rd., Mail Stop M615, Mesa, AZ 85215-9734; telephone 1-800-388-3378; fax 480-346-6813; or at http://www.mdhelicopters.com. You may review a copy of the referenced service information at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy, Room 6N-321, Fort Worth, TX 76177. ### For further information contact Galib Abumeri, Aviation Safety Engineer, Los Angeles ACO Branch, Compliance & Airworthiness Division, FAA, 3960 Paramount Blvd., Lakewood, CA 90712; telephone (562) 627-5374; email galib.abumeri@faa.gov. ### Discussion On November 26, 2018, at 83 FR 60376, the Federal Register published our notice of proposed rulemaking (NPRM), which proposed to amend 14 CFR part 39 by adding an AD that would apply to MDHI Model 369A, 369D, 369E, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters with a Helicopter Technology Company, LLC (HTC), MRB part number 369A1100, 369D21100, 369D21102, 369D21120, 369D21121, 369D21123, 500P2100, or 500P2300 installed. The NPRM was prompted by reports of two operators finding cracks on an HTC-manufactured MRB and proposed to require repetitively inspecting each MRB trim tab for a crack. The proposed requirements were intended to prevent failure of an MRB and subsequent loss of control of the helicopter. In the “Costs of Compliance” section, the NPRM stated an incorrect number of U.S.-registered helicopters affected by this AD and subsequently, an incorrect estimated cost of the inspection for the U.S. fleet. We have corrected the cost information in this Final rule. ### Comments We gave the public the opportunity to participate in developing this AD, but we did not receive any comments on the NPRM. ### 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 We reviewed HTC Mandatory Service Bulletin Notice No. 2100-9, dated May 25, 2017 (SB 2100-9), which contains procedures for inspecting each MRB for a crack in an area adjacent to the inboard edge of the MRB trim tab. We also reviewed MD Helicopters Service Bulletin No. SB369D-221, SB369E-119, SB369F-106, SB369H-257, SB500N-057, and SB600N-069, each dated April 2, 2018. This service information specifies inspecting the MRBs for cracks near the trim tab by following the instructions in SB 2100-9. ### Differences Between This AD and the Service Information The service information specifies procedures for inspecting each MRB for nicks, gouges, and scratches. This AD does not, as the unsafe condition concerns a crack in the MRB. ### Costs of Compliance We estimate that this AD affects 730 helicopters of U.S. Registry. We estimate that operators may incur the following costs in order to comply with this AD. Labor costs are estimated at $85 per work-hour. Inspecting one MRB requires about 0.1 work-hour, for an estimated cost per helicopter of $43 for the 705 MDHI Model 369-series and 500N helicopters (5 MRBs), $51 for the 25 MDHI Model 600N helicopters (6 MRBs), and a total estimated cost of $31,590 for the U.S. fleet per inspection cycle. If required, replacing one MRB requires about 3 work-hours and parts cost about $13,000 for a total estimated cost of $13,255 per MRB. ### 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, 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. ### Adoption of the Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS H3WE](https://openairdocs.org/tcds/H3WE): MD Helicopters LLC; names 10 of 12 models: 369D, 369E, 600N, 369FF, 369HS, 369HM, 500N, 369HE… ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 673 (673 by airframe model, 0 by engine model) - Makers: Hughes Helicopters 241, MD Helicopters 167, Mcdonnell Douglas Helicopter 124, Hughes 116, Mcdonnell Douglas Heli 17, Summa 5, Hughes/Batto John 1, Hughes/Helicopter Assocs 1, Mcdonnell Douglas Mdhs 1 Models with the most aircraft: - [Hughes Helicopters HUGHES 369D](https://openairdocs.org/model/hughes-helicopters-hughes-369d): 207 aircraft (airframe model) - [MD Helicopters 369FF](https://openairdocs.org/model/md-helicopters-369ff): 94 aircraft (airframe model) - [Mcdonnell Douglas Helicopter 369E](https://openairdocs.org/model/mcdonnell-douglas-helicopter-369e): 83 aircraft (airframe model) - [Hughes 369HS](https://openairdocs.org/model/hughes-369hs): 69 aircraft (airframe model) - [MD Helicopters 369E](https://openairdocs.org/model/md-helicopters-369e): 42 aircraft (airframe model) - [Hughes 369A](https://openairdocs.org/model/hughes-369a): 32 aircraft (airframe model) - [Hughes Helicopters 369E](https://openairdocs.org/model/hughes-helicopters-369e): 29 aircraft (airframe model) - [Mcdonnell Douglas Helicopter 500N](https://openairdocs.org/model/mcdonnell-douglas-helicopter-500n): 27 aircraft (airframe model) - [Mcdonnell Douglas Heli 369FF](https://openairdocs.org/model/mcdonnell-douglas-heli-369ff): 17 aircraft (airframe model) - [Mcdonnell Douglas Helicopter 600N](https://openairdocs.org/model/mcdonnell-douglas-helicopter-600n): 14 aircraft (airframe model) - [MD Helicopters 500N](https://openairdocs.org/model/md-helicopters-500n): 13 aircraft (airframe model) - [MD Helicopters 600N](https://openairdocs.org/model/md-helicopters-600n): 12 aircraft (airframe model) - [Hughes 369A (OH-6A)](https://openairdocs.org/model/hughes-369a-oh-6a): 11 aircraft (airframe model) - [Hughes Helicopters 369FF](https://openairdocs.org/model/hughes-helicopters-369ff): 5 aircraft (airframe model) - [Summa 369D](https://openairdocs.org/model/summa-369d): 4 aircraft (airframe model) - [MD Helicopters 369HS](https://openairdocs.org/model/md-helicopters-369hs): 3 aircraft (airframe model) - [Hughes 369HE](https://openairdocs.org/model/hughes-369he): 3 aircraft (airframe model) - [MD Helicopters 369HM](https://openairdocs.org/model/md-helicopters-369hm): 2 aircraft (airframe model) - [Summa 369HS](https://openairdocs.org/model/summa-369hs): 1 aircraft (airframe model) - [MD Helicopters 369A](https://openairdocs.org/model/md-helicopters-369a): 1 aircraft (airframe model) All 26 models: https://openairdocs.org/ad/2019-05-04/models.md Every aircraft: https://openairdocs.org/ad/2019-05-04/aircraft.md ## Related documents - [Proposed rule FAA-2018-0991](https://openairdocs.org/proposed/FAA-2018-0991): Notice of proposed rulemaking (NPRM), published Nov 26, 2018 Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.