AD/B717/26 Versatile Integrated Avionics Digital Computer (Cth)

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 39.001(1) of CASR 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.

Boeing 717 Series Aeroplanes

AD/B717/26 Versatile Integrated Avionics Digital Computer 12/2007

Applicability:	Model 717-200 aeroplanes, as identified in Boeing Service Bulletin (SB) 717-31-0013, dated 25 March 2005.
Requirement:	1.    If not previously accomplished, upgrade the versatile integrated avionics (VIA) digital computer with new system software part number (P/N) PS4081970-909 and in-service data acquisition system (ISDAS) database software P/N PS4081642-909, in accordance with the Accomplishment Instructions of SB 717-31-0013.
Accomplishing this upgrade or the installation of VIA P/N 4081570-909 or subsequent terminates the requirements of AD/B717/15 for that aeroplane only.
Note 1:  SB 717-31-0013 refers to Honeywell Alert SB 4081570-31-A6007, dated 9 March 2005, as an additional source of service information for doing the actions specified in Requirement 1 of this Directive.
2.    VIA digital computer, P/N 4081570-904, -905, -906 or -907, may not be installed on any aeroplane as a replacement spare.
Later revisions of SB 717-31-0013, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2007-19-15, are considered acceptable for compliance with the equivalent Requirements of this Directive.
Note 2:  FAA AD 2007-19-15 Amdt 39-15206 refers.
Compliance:	For Requirement 1 - Within 18 months after the effective date of this Directive.
For Requirement 2 - As of the effective date of this Directive.
This Airworthiness Directive becomes effective on 22 November 2007.
Background:	This Directive provides terminating action for AD/B717/15.  AD/B717/15 currently requires a revision to the Limitations Section of the aircraft flight manual (AFM) to prohibit use of the flight management system (FMS) profile (PROF) mode for descent and/or approach operations unless certain conditions are met.  AD/B717/15 will be cancelled in May 2009 when all affected aircraft will be in compliance with this Directive.

This Directive requires upgrading the versatile integrated avionics (VIA) digital computer with new system software, which would end the need for the AFM revision.  This Directive results from a report of two violations of the selected flight control panel (FCP) altitude during FMS PROF descents.  The Directive is issued to prevent, under certain conditions during the FMS PROF descent, the un-commanded descent of an aeroplane below the selected level-off altitude, which could result in an unacceptable reduction in the separation between the aeroplane and nearby air traffic or terrain.

David Punshon
Delegate of the Civil Aviation Safety Authority

2 October 2007