AD/INST/45 - Honeywell Air Data Inertial Reference Units

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Instruments and Automatic Pilots

 

AIRWORTHINESS DIRECTIVE


For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

 

AD/INST/45 Honeywell Air Data Inertial Reference Units 6/2000 DM

Applicability: Honeywell air data inertial reference units (ADIRU) having a serial number below 0841 and a part number (P/N) listed below:

 

Aeroplane Manufacturer

Model

ADIRU P/N

Boeing

757-300

HG2050AC02

 

737-600

HG2050AC03

 

737-700

HG2050AC04

 

737-800

HG2050AC05

Airbus

A319-111, A319-112, A319-113, A319-114, A319-131, A319-132, A320-111, A320-211, A320-212, A320-214, A320-231, A320-232, A320-233, A321-111, A321-112, A321-131, A330-202, A330-301, A330-223, A330-321, A330-322, A330-323, A340-211, A340-311, A340-212, A340-312, A340-213, A340-313

HG2030AD09

Airbus

A330-202, A330-301, A330-223, A330-321, A330-322, A330-323, A340-211, A340-311, A340-212, A340-312, A340-213, A340-313

HG2030AD10

 

Requirement: 1. Inspect the identification plate of the ADIRU to determine its modification status, in accordance with Honeywell Alert Service Bulletin (ASB) HG2030AD-34- A0009 (for an ADIRU having P/N HG2030AD09 or HG2030AD10) or ASB HG2050AC-34-A0008 (for an ADIRU having P/N HG2050AC02, HG2050AC03,

HG2050AC04, or HG2050AC05), both dated 9 March 2000; as applicable.

 

2.    If any ADIRU having P/N HG2050AC02, HG2050AC03, HG2050AC04, or HG2050AC05 is not marked as modification 2 or 3 replace the ADIRU with an ADIRU specified in either Requirement 2.a. or 2.b. below, in accordance with Honeywell ASB HG2050AC-34-A0008, dated 9 March 2000.

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

 

 

 

  1. Replace with an ADIRU that has P/N HG2050AC03, HG2050AC04, or HG2050AC05; and that is marked as modification 2 or 3;

 

Or,

 

b.    Replace with a serviceable ADIRU that has P/N HG2050AC03, HG2050AC04, or HG2050AC05; and that is not marked as modification 2 or 3; and that has been determined to have accumulated less than 7,000 hours time in service in accordance with the ASB.

 

3.    If any ADIRU having P/N HG2030AD09 or HG2030AD10 is not marked with modification 3 or 6, replace the ADIRU with an ADIRU specified in either Requirement 3.a. or 3.b. below, in accordance with Honeywell ASB HG2030AD- 34-A0009, dated 9 March 2000.

 

  1. Replace with an ADIRU having P/N HG2030AD09 or HG2030AD10 that is marked as modification 3 or 6;

 

Or,

 

b.    Replace with a serviceable ADIRU having P/N HG2030AD09 or HG2030AD10 that is not marked as modification 3 or 6, and that has been determined to have accumulated less than 7,000 hours time in service in accordance with the ASB.

 

Note 1: For purposes of this Directive, a "serviceable" ADIRU is one that satisfies the replacement requirements of Requirement 2.b. or 3.b. and on which no critical inertial reference failure has occurred.

 

Installation of all ADIRUs on the aeroplane that meet the criteria of the following sub paragraphs constitutes terminating action for the requirements of this Directive:

 

  1. ADIRUs that have P/N HG2050AC03, HG2050AC04, or HG2050AC05; and that are marked as modification 2 or 3;

 

b.    ADIRUs that have P/N HG2030AD09 or HG2030AD10, and that are marked as modification 3 or 6.

 

Note: FAA AD 2000-07-27 Amdt 39-11683 refers.

 

Compliance:  For Requirement 1 - Prior to the next flight following any critical inertial reference failure of an ADIRU.

 

For Requirement 2 - Before further flight.

 

 

 

For Requirement 3 - Before further flight.

 

This Airworthiness Directive becomes effective on 3 May 2000.

 

Background:  The Federal Aviation administration has received reports of dual critical failures of inertial reference units on ADIRUs during flight. The actions specified in this Directive are intended to prevent loss of the main sources of attitude data, consequent high pilot workload, and a significant increase in the likelihood of pilot error.

 

This Directive requires inspection of a failed ADIRU to determine its modification status, and replacement of an unmodified failed ADIRU with a serviceable ADIRU. The Directive also provides for optional terminating action.


James Coyne

Delegate of the Civil Aviation Safety Authority 27 April 2000

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


The above AD is notified in the Commonwealth of Australia Gazette on 3 May 2000.

Overview

The Airworthiness Directive (AD) issued under subregulation 39.1(1) of the Civil Aviation Regulations 1998 (CAR 1998) pertains to the Honeywell Air Data Inertial Reference Units (ADIRU). Enacted in 2000, this directive was introduced to address safety concerns related to the potential for critical failures of inertial reference units in ADIRUs during flight. The directive was issued by the Civil Aviation Safety Authority (CASA) delegate, James Coyne, to mitigate the risk of loss of primary attitude data, which could lead to increased pilot workload and a higher likelihood of pilot error. The directive mandates specific inspections and replacements of ADIRUs with particular part numbers and modification statuses to ensure compliance with safety standards and prevent critical failures.

Scope and Application

The Airworthiness Directive (AD) issued under subregulation 39.1(1) of the Civil Aviation Regulations 1998 (CAR 1998) applies specifically to Honeywell air data inertial reference units (ADIRU) with certain serial numbers and part numbers installed on specified Boeing and Airbus aircraft models. The directive mandates actions to address safety concerns identified with the ADIRUs, including inspection to determine modification status and replacement of unmodified units with serviceable units marked as specific modifications. This requirement must be undertaken in accordance with Honeywell's Alert Service Bulletins dated 9 March 2000. The directive takes effect on 3 May 2000 and applies to aircraft operating within the Commonwealth of Australia, overseen by the Civil Aviation Safety Authority (CASA). There are no stated exclusions or exemptions in this directive; it applies comprehensively to the specified aircraft and ADIRU configurations within the jurisdiction of CASA. Compliance with the directive is mandatory, with specific timelines provided for inspections and replacements following critical inertial reference failures or before further flight, as applicable.

Key Provisions

The Airworthiness Directive (AD) issued under subregulation 39.1 (1) of the Civil Aviation Regulations 1998 (CAR 1998) applies to specific Honeywell Air Data Inertial Reference Units (ADIRU) with serial numbers below 0841 and certain part numbers (P/N) listed in the applicability section (section 6/2000 DM). These parts include HG2050AC02, HG2050AC03, HG2050AC04, HG2050AC05, HG2030AD09, and HG2030AD10. The AD pertains to specific models of Boeing and Airbus aircraft. The primary requirement (section 1) is to inspect the identification plate of the ADIRU to ascertain its modification status, following the Honeywell Alert Service Bulletins (ASB) HG2030AD-34-A0009 or HG2050AC-34-A0008 dated 9 March 2000, as applicable. The AD imposes specific obligations on the parties or entities it governs. For instance, if an ADIRU having P/N HG2050AC02, HG2050AC03, HG2050AC04, or HG2050AC05 is not marked as modification 2 or 3, it must be replaced with an ADIRU that meets certain criteria (section 2). Similarly, if an ADIRU having P/N HG2030AD09 or HG2030AD10 is not marked with modification 3 or 6, it must also be replaced with an ADIRU meeting specific criteria (section 3). The AD further stipulates that installation of all ADIRUs that meet the criteria of the following sub paragraphs constitutes terminating action for the requirements of this Directive (section 3). Failure to comply with the AD may result in severe consequences. The AD does not explicitly state any specific penalties, but non-compliance could lead to the aircraft being deemed unairworthy, which could result in operational restrictions or grounding of the aircraft. Furthermore, in cases where the AD is issued to address safety concerns, non-compliance could potentially lead to more severe civil or criminal penalties if the non-compliance results in an accident or incident. The AD becomes effective on 3 May 2000 (section Compliance).

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Sourced from the Federal Register of Legislation at 26 August 2026. For the latest information on Australian Government law please go to https://www.legislation.gov.au.