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 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/B717/15 Flight Management System 11/2004

Applicability: Model 717-200 series aeroplanes.

Requirement: Amend the Limitations Section of Aircraft Flight Manual (AFM) to include the following statement. This may be accomplished by inserting a copy of this Directive into the AFM.

"Use of PROF mode for descent and/or approach operations is prohibited unless

1. The aeroplane is on path and the FMA indicates THRUST | xxx | PROF, or

2.        The indicated airspeed is below VMAX for the aeroplane configuration by at least:

1. 10 knots at indicated altitudes below 10,000 feet, or

b.        15 knots at indicated altitudes of 10,000 feet or above, or

3.        Basic autoflight modes (e.g., LVL CHG V/S, or FPA) are used to recapture the path when the PROF mode is engaged and the aeroplane is:

1. Above or below the path and the FMA indicates PITCH | xxx | IDLE, or

b.        Below the path and the FMA indicates THRUST | xxx | V/S."

When a statement identical to that above has been included in the general revisions of the AFM and the general revisions have been inserted into the AFM, the copy of this Directive may be removed from the AFM.

Note: FAA AD 2004-18-04 Amdt 39-13782 refers.

Compliance: Within 60 days after the effective date of this Directive

This Airworthiness Directive becomes effective on 28 October 2004.

Boeing 717 Series Aeroplanes

AD/B717/15 (continued)

Background: The United States Federal Aviation Administration (FAA) has received reports of two violations of the selected flight control panel (FCP) altitude during flight management system (FMS) profile (PROF) mode descents on McDonnell Douglas MD-11 aeroplanes. Investigation by the aeroplane and avionics manufacturers revealed that under certain conditions during an FMS PROF descent, the FMS will allow an aeroplane to descend below the selected FCP altitude or FMS-constrained altitude or both. In addition, the FMS will not command the autopilot or flight director to level off at the next altitude constraint, if a specific series of events occur and the airspeed of the aeroplane is within the overspeed detection window during an FMS descent.

As the FMS software on 717-200 aeroplanes is identical to that on the affected MD- 11 aeroplanes, 717-200 aeroplanes may be subject to the same unsafe condition.

This Directive requires a revision to the Limitations Section of the AFM to prohibit use of the FMS PROF mode for descent and/or approach operations unless certain conditions are met. This action is designed to prevent, under certain conditions during the FMS PROF descent, the uncommanded 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.

James Coyne

Delegate of the Civil Aviation Safety Authority 16 September 2004

The above AD is notified in the Commonwealth of Australia Gazette on 6 October 2004.