Commonwealth legislation

AD/ENST 28/36 - Lamiflex Bearings

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This Airworthiness Directive forces Enstrom F‑28 operators to inspect and, where necessary, remove and replace specific Lamiflex elastomeric bearings (P/N 28‑14320‑12, 28‑14320‑15). Bearings with illegible manufacture dates or older than five years must be removed; inspections are required within five hours of 26 Sep 1994 and then every 100 hours. The Directive cites reported delaminations that can cause bearing failure and loss of control. Operators bear inspection, replacement, downtime and recordkeeping costs and must follow Enstrom Service Directive Bulletin No. 0081 Rev. A.

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AD/ENST 28/36 - Lamiflex Bearings

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Enstrom F-28 Series Helicopters

AD/ENST 28/36 Lamiflex Bearings 12/94 TX

Applicability: Models F28A, C, C2, F; 280, 280C, F and FX with main rotor feathering elastomeric Lamiflex bearings P/N 28-14320-12 or 28-14320-15.

Requirement: 1. Action in accordance with Enstrom Service Directive Bulletin No. 0081 Rev. A.

2. Remove from service any Lamiflex bearing where the Date of Manufacture is:

not visible or illegible, or

b. marked as being manufactured five years prior to any inspection carried out in accordance with this Directive.

Note: FAA AD 94-17-15 refers.

Compliance: Within five hours time in service after 26 September 1994. Thereafter at intervals not exceeding 100 hours time in service; and anytime the symptoms specified in paragraphs 4.1.1 to 4.1.4 of the Requirement Document are experienced.

Background: There have been reports of several failures of the subject bearings where the bearings have delaminated and extruded rubber and brass. Continued operation in this condition may result in complete delamination, resulting in failure of the bearing, and loss of control of the helicopter. This Directive also imposes a five year since manufacture calendar life on the bearings.

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

1 AD/ENST 28/36 - Lamiflex Bearings