Commonwealth legislation

AD/INST/26 - Navomatic 200A Automatic Pilot Computer - Amplifier Nav Input - Modification

RepealedCTH

This Act has been repealed and is no longer in force. It is retained for historical reference.

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

2/10 complexity

What this is: A mandatory safety directive (an "Airworthiness Directive") requiring a specific hardware fix for certain aircraft autopilot systems.

Who it affects: Owners or operators of aircraft fitted with ARC CA-295B computer-amplifiers (serial numbers up to 3550) that connect to navigation signals carrying a significant DC voltage from earth (ground).

What you must do: Modify the autopilot computer so it can safely accept voltages up to positive 8 volts. The technical instructions are found in either:

ARC Field Engineering Service Bulletin 211; or
Cessna Avionics Service Letter AV78-28

Deadline: Complete the modification within 200 hours of flight time after 31 January 1979.

Why this matters: Without this modification, the autopilot could malfunction when processing navigation signals with certain electrical characteristics, potentially causing loss of automatic flight control.

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Direct links to the current provisions in AD/INST/26 - Navomatic 200A Automatic Pilot Computer - Amplifier Nav Input - Modification.

AD/INST/26 - Navomatic 200A Automatic Pilot Computer - Amplifier Nav Input - Modification

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

View image in the official source Instruments and Automatic Pilots

AD/INST/26 Navomatic 200A Automatic Pilot Computer - Amplifier Nav Input - Modification

1/79

Applicability: ARC CA-295B computer-amplifiers up to S/No. 3550 that connect to a navigation signal having a significant DC voltage from earth.

Document: 1. ARC Field Engineering SB 211; or

Cessna Avionics SL AV78-28.

Compliance: Within 200 hours time in service after 31 January 1979.

Background: This Directive introduces a modification by which a computer amplifier may accept voltages of up to 'plus' 8 volts.

Source text

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