Document ID: chunk:federal_register_of_legislation:F2009L01968:body:0:p2
Version: federal_register_of_legislation:F2009L01968
Segment Type: other
Provision Reference: 
Character Range: 6076–9819

Honeywell ASB 7018879-34-A6060, Revision 001, dated                                           The NAV computer identified in ASB 7018879-34-A6060, Revision 001
                                                                                                                                                                                                                                                                                     21 January 2008
                                                                                                                                                                                                                                                                                     Honeywell ASB 7018879-34-A6062, dated 12 June 2007                                            The NAV computer identified in ASB 7018879-34-A6062
                                                                                                                                                                                                                                                                                     Honeywell ASB 7018879-34-A6063, dated 6 July 2007                                             The NAV computer identified in ASB 7018879-34-A6063
             Actions accomplished before the effective date of this Amendment in accordance with Honeywell Service Bulletin 7017300-22-A6112, dated 22 June 2007, are acceptable for compliance with the software upgrade to the IC-800 or IC-800E IACs.
             Later revisions of the above SB(s), approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2009-08-01, are considered acceptable for compliance with the equivalent Requirements of this Directive.
             Note 3:  FAA AD 2009-08-01 Amdt 39-15874 refers.
Compliance:  For Requirements 1 and 2 - Within 14 days after the effective date of this Amendment.
             For Requirement 3 - Within 12 months after the effective date of this Amendment.
             This Amendment becomes effective on 4 June 2009.

Background:  The FAA has received reports of in-flight unannunciated shifts of computed position in aeroplanes with Honeywell NZ-2000 navigation and IC-800 integrated avionics computers serving Honeywell FMSs.  The computed position shift, attributed to a software design error induced during a previous software modification, occurs when the number of inertial reference units (IRUs) supplying data to the FMS degrades from 3 to 2 or from 2 to 1, or increases from 2 to 3 or from 1 to 2.
             If the FMS system is coupled to an autopilot or flight director system, this shift in the FMS computed position could result in uncommanded deviations from the intended flight path of the aeroplane and, if those deviations are undetected by the flight crew, compromise terrain and/or traffic avoidance.
             The original issue of this Directive required affected units to be identified and, if necessary, introduced a temporary revision to the AFM Limitations Section.  This was considered an interim action, as the manufacturer was developing a modification that would address the unsafe condition.
             This Amendment continues the Requirements of the original issue of the Directive and introduces a terminating action which allows the removal of the AFM temporary revision.  The Amendment also adds the IC-800E IAC to the applicability and removes Hawker 800XP and 1000 from the list of possible affected aeroplanes.
             The original issue of this Directive became effective on18 April 2007.

James Coyne
Delegate of the Civil Aviation Safety Authority

24 April 2009