Commonwealth legislation

AD/TB20/18 - Fuel System

In ForceCTH

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

4/10 complexity

This Civil Aviation Safety Authority Airworthiness Directive requires owners/operators of Aerospatiale (Socata) TB20 and TB21 aeroplanes (serials 1–730) to install a check valve and replace the factory Dukes electric boost pump with a specified Weldon pump, using the manufacturer service bulletins and kit numbers provided. The mechanical changes are intended to stop fuel siphoning and ensure the boost pump can displace air if the engine-driven pump loses prime. Compliance was required by 31 October 1991; owners/operators bear the costs and must install the kits to maintain airworthiness.

JSON API

Deep dive

Want the full deep dive?

Zoe can write the in-depth analysis on top of the summary above: how it works, who it affects and what each part actually does.

Current sections

Direct links to the current provisions in AD/TB20/18 - Fuel System.

AD/TB20/18 - Fuel System

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

View image in the official source
Aerospatiale (Socata) TB20 (Trinidad) Series Aeroplanes

AD/TB20/18 Fuel System 10/90

Applicability: Model TB20 and TB21 with serial numbers 1 through 730.

Requirement: For model TB20: Install a check valve into the fuel system in accordance with Socata Service Bulletin number 47/1 and kit 9128.

For model TB20 and TB21: Replace the Dukes pump P/N 463400 with a Weldon pump P/N TB20/6101/5000 (TB20) or P/N TB20/6101/5003 (TB21) respectively in accordance with kits 9132 and 9133.

Note: DGAC AD 89-183-(A)R1 refers.

Compliance: Prior to 31 October 1991.

Background: The inability of the normally fitted electric fuel boost pump to operate in a dry condition if the engine driven fuel pump loses its prime when the engine is stopped, could result in air being drawn into the fuel lines causing power interruption or loss. Installation of a check valve will prevent fuel from siphoning back into the fuel tank when the engine is stopped and the fuel selector is not in the off position; and installation of an electric fuel boost pump which incorporates a solid rotor design, will displace air in the system within its operating parameters.

Source text

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

1 AD/TB20/18 - Fuel System