Commonwealth legislation

AD/FSM/22 - POSA Carburettor - Modification

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legislative instrument

Plain English Summary

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This directive requires modification of all Posa carburettors fitted to converted Volkswagen engines to reduce the risk of in‑flight fuel starvation. It compels incorporation of a Revmaster service rework and fixes to prevent parts loosening and fuel pooling.

It applies to aircraft owners/operators and maintenance organisations; compliance is required within ten hours for engines in service and before issue of a Permit to Fly for new engines. The stated purpose is to stop main metering needles turning in flight (Background).

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AD/FSM/22 - POSA Carburettor - Modification

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Fuel Supply and Metering Equipment

AD/FSM/22 POSA Carburettor - Modification 5/83

Applicability: All model Posa Carburettors as fitted to converted V.W. Engines. These carburettors may be fitted to, but not necessarily confined to the Revmaster and H.A.P.1 V.W. Conversion ranges of engines.

Requirement: (i) Incorporate Revmaster Bulletin No. 001 "Injector Rework" dated 30 July 1973.

(ii) Lockwire choke idle screw.

(iii) Lock all body screws.

(iv) Provide overboard drain, well clear of exhaust, to drain throttle valve of excess fuel during start up.

Compliance: Engines in Service: Within ten hours in service after 31 May 1983. New Engines: Before issue of Permit to Fly.

Background: This Directive was originally issued as part of AD/REV/4 pertaining to Revmaster engines. It is now issued under subject heading to cover all Posa Carburettors fitted to any converted V.W. engine. A Posa Carburettor Service Bulletin issued by the Hapi Engine Organisation and dated February 23, 1983 reports of two inflight fuel starvation incidents caused by the main metering needle turning in flight. While the Posa (Hapi) Bulletin proposes that certain inspection actions be taken to obviate further incidents of this nature it should be accepted that the modification action required by this Directive is a more positive and long term answer for overcoming this problem.

Source text

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

1 AD/FSM/22 - POSA Carburettor - Modification

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Fuel Supply and Metering Equipment

AD/FSM/22 POSA Carburettor - Modification 5/83

Requirement: (i) Incorporate Revmaster Bulletin No. 001 "Injector Rework" dated 30 July 1973.

(ii) Lockwire choke idle screw.

(iii) Lock all body screws.

(iv) Provide overboard drain, well clear of exhaust, to drain throttle valve of excess fuel during start up.

Compliance: Engines in Service: Within ten hours in service after 31 May 1983. New Engines: Before issue of Permit to Fly.