AIRWORTHINESS DIRECTIVE
For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.
Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters
AD/DAUPHIN/77 Main Gearbox (MGB) Planet Gear Carrier 2/2005
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Applicability: EUROCOPTER helicopters: SA 365 N and N1, AS 365 N2 and N3, SA 366 G1, SA 365 C, C1, C2 and C3, SA 360, EC 155 B, B1.
Requirement: | 1. | Carry out a boroscope inspection in accordance with Paragraph 2B of the applicable reference document. |
| 2 | Carry out a visual inspection in accordance with Paragraph 2B.3 of the applicable reference document |
REFERENCE PUBLICATIONS:
EUROCOPTER AS 365 N Alert Telex No. 05.00.48 EUROCOPTER SA 366 Alert Telex No. 05.33 EUROCOPTER SA 360 and SA365 C Alert Telex No. 05.26 EUROCOPTER EC 155 Alert Telex No. 05A007
(Any subsequent approved revision to these Alert Telexes is acceptable).
Note: DGAC UF 2004-194 (EASA reference No 2004-12387 dated 17 December 2004) refers.
Compliance: For requirement 1:
MGBs with less than 250 hours Time In Service (TIS), before exceeding 265 hours TIS, and thereafter at intervals not to exceed 50 flying hours.
MGBs with 250 flying hours TIS or more, within 15 hours TIS after the effective date of this Directive, and thereafter at intervals not to exceed 50 flying hours.
For requirement 2:
Before installation in the rotorcraft
This Airworthiness Directive becomes effective on 30 December 2004.
Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters
AD/DAUPHIN/77 (continued)
Background: This AD is issued following cases of cracks that were discovered in the web of the planet gear carriers of the main gearbox, but which did not provide any indication on the magnetic plug, as detailed in AD/DAUPHIN/74.
The cracks were discovered upon inspection of the MGB’s using a boroscope, even though chips were not showing on the magnetic plug. Rupture of the web of the planet gear carrier can lead to seizure of the MGB.
James Coyne
Delegate of the Civil Aviation Safety Authority 23 December 2004
The above AD is notified in the Commonwealth of Australia Gazette on 24 December 2004.
Overview
The Airworthiness Directive (AD) AD/DAUPHIN/77 issued under subregulation 39.1(1) of the Civil Aviation Safety Regulations 1998 by a delegate of the Civil Aviation Safety Authority (CASA) on 23 December 2004, targets a specific safety issue identified in the main gearbox planet gear carriers of the Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters. This directive aims to address the problem of cracks in the web of the planet gear carriers that may not be detected by the magnetic plug, which can potentially lead to the seizure of the main gearbox. The AD mandates a borescope inspection and a visual inspection according to specified paragraphs in the applicable reference documents and outlines the compliance intervals based on the time in service of the main gearboxes. The policy objective behind this directive is to ensure the continued airworthiness and safety of the affected helicopters by preventing potential mechanical failures through regular and rigorous inspections.
The AD/DAUPHIN/77 was published in the Commonwealth of Australia Gazette on 24 December 2004 and became effective on 30 December 2004. The directive applies to various models of the Eurocopter SA 360 and SA 365 series, including the SA 365 N and N1, AS 365 N2 and N3, SA 366 G1, SA 365 C, C1, C2 and C3, SA 360, EC 155 B, and B1. The directive was introduced in response to documented instances of gear carrier cracks, as referenced in previous AD/DAUPHIN/74, and aims to mitigate the risk of such cracks leading to catastrophic failure by establishing stringent inspection protocols.
Scope and Application
The Airworthiness Directive (AD) AD/DAUPHIN/77 applies to specific models of Eurocopter SA 360 and SA 365 (Dauphin) Series helicopters, including SA 365 N and N1, AS 365 N2 and N3, SA 366 G1, SA 365 C, C1, C2 and C3, SA 360, EC 155 B, B1. This AD is issued by the delegate of the Civil Aviation Safety Authority (CASA) under subregulation 39.1 (1) of the Civil Aviation Safety Regulations 1998, aimed at addressing an identified unsafe condition in the main gearbox planet gear carriers of these helicopters. The directive mandates specific actions to be taken, including a boroscope inspection and a visual inspection, in accordance with detailed instructions provided in the requirement section of the AD. These inspections must be conducted at specified intervals based on the Time In Service (TIS) of the main gearboxes. The AD is effective as of 30 December 2004 and requires compliance within specified timeframes, ensuring the continued airworthiness of the affected helicopters.
Key Provisions
The Airworthiness Directive (AD) issued under subregulation 39.1(1) of the Civil Aviation Safety Regulations 1998 (CASR 1998) mandates specific actions to address safety concerns in certain Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters. This directive, numbered AD/DAUPHIN/77, focuses on the main gearbox (MGB) planet gear carrier, particularly its web, which has shown a propensity for cracking without indication on the magnetic plug. The AD applies to specific models and series of Eurocopter helicopters, including the SA 365 N and N1, AS 365 N2 and N3, SA 366 G1, SA 365 C, C1, C2 and C3, SA 360, EC 155 B, and B1, as detailed in the applicability section.
The directive requires two primary actions to be undertaken by operators and owners of the affected helicopters. Firstly, a boroscope inspection must be conducted in accordance with Paragraph 2B of the applicable reference document. Secondly, a visual inspection must be performed in accordance with Paragraph 2B.3 of the same reference document. These inspections are crucial for identifying any cracks in the web of the planet gear carrier of the MGB. The compliance schedule stipulates that inspections must be carried out under specific conditions: for MGBs with less than 250 hours of Time In Service (TIS), inspections are required before exceeding 265 hours TIS and subsequently at intervals not exceeding 50 flying hours. For MGBs with 250 hours TIS or more, inspections must be conducted within 15 hours TIS after the effective date of this directive and thereafter at intervals not exceeding 50 flying hours. A visual inspection must also be performed before the installation of the MGB in the rotorcraft.
Failure to comply with the requirements of this AD could result in serious safety risks, including the potential seizure of the MGB due to rupture of the web of the planet gear carrier. The directive became effective on 30 December 2004, and operators and owners must ensure that the mandated inspections are performed according to the specified timelines and procedures. The AD references several EUROCOPTER Alert Telexes and a DGAC UF 2004-194 document for further guidance. Any approved revisions to these referenced documents are also acceptable.