Applicability: Model SA 365 N, SA 365 N1, AS 365 N2, AS 365 N3, SA 365 C, SA 365 C1, SA 365 C2, and SA 365 C3 helicopters, all serial numbers, if a main rotor head (MRH) fitted with frequency adapters and frequency adapter bushes is installed, as referenced below:

• pre MOD 0762C39 and used in hot climatic conditions and/or tropical and damp atmosphere, or
• post Mod 0762C39.

The part numbers of the affected frequency adapters and frequency adapter bushes are listed in paragraph 2.B.2.v and paragraph 2.B.5 of Eurocopter AS 365 Alert Service Bulletin (ASB) No. 62.00.24 and SA 365 ASB No. 65.45, as applicable.

Note 1: The use of a helicopter in tropical and damp atmosphere is defined as follows: A helicopter operated in climatic conditions with outside air temperatures from 28 degrees centigrade upward combined with relative humidity from 75% upward.

Note 2: The use of a helicopter in hot climatic conditions is defined as follows: A helicopter operated in areas with high solar radiation temperatures above 40 degrees centigrade.

Requirement:

1. A MRH fitted with frequency adapters pre MOD 0762C39 and operated in hot climatic conditions and/or in tropical and damp atmosphere: Modify the frequency adapters and frequency adapter bushes per MOD 0762C39, in accordance with paragraphs 2.B.1, 2.B.2 and 2.B.3 of AS 365 ASB No. 62.00.24 and SA 365 ASB No. 65.45, as applicable.
2. A MRH fitted with frequency adapters post MOD 0762C39: Check that the lockwire is in place and that the holes in the frequency adapters and in the frequency adapter bushes are not blocked, in accordance with paragraph 2.B.6 of AS 365 ASB No. 62.00.24 and SA 365 ASB No. 65.45, as applicable.
3. If the lockwire is in place on the trailing edge of the frequency adapter and if the four holes are not blocked, flights may be resumed.
4. If the lockwire is not in place, before further flight, re-position the bush if it has turned, and fit the lockwire.
5. If one hole or more is/are blocked, before further flight, unblock the hole(s). After the effective date of this Directive, no person may install any of the following equipment held as spares and intended for use in hot climatic conditions and/or in tropical and damp atmosphere:
6. 1. MRHs fitted with frequency adapters,
   2. Frequency adapter assemblies,
   3. Non-drilled frequency adapter bushes, on a helicopter as a replacement part, unless it has been modified in accordance with paragraph 2.B.2 or 2.B.4 or 2.B.5 of AS 365 ASB No. 62.00.24 and SA 365 ASB No. 65.45, as applicable.

Note: EASA Emergency AD 2006-0362-E refers.

Compliance:

• Within 110 flight hours after 2 December 2006.
• Within 10 flight hours after application of MOD 0762C39, or within 10 flight hours after 2 December 2006, whichever occurs later, and thereafter at intervals not to exceed 10 flight hours.

This Airworthiness Directive becomes effective on 2 December 2006.

Background: The EASA received reports of deterioration and two reports of failure of Starflex star arm ends. Such deterioration generated high-amplitude vibrations in flight, compelling the pilot to carry out a precautionary landing, in both cases. A failure of the Starflex star arm end could make it impossible to control the helicopter. The deteriorations are due to the strong effect of temperature on the strength of the Starflex star arm end attachment.

FMI: www.casa.gov.au