COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Twin Commander (Gulfstream/Rockwell/ Aerocommander 500, 600 and 700) Series Aeroplanes

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/AC/98 Operation of Deicing Boots 7/2000

Applicability: All models 680, 680E, 680F, 680FL, 680FL(P), 680T, 680V, 680W, 681, 685, 690,

690A, 690B, 690C, 690D, 695, 695A and 695B aircraft fitted with pneumatic deicing boots.

Requirement: Revise the Limitations Section of the aircraft's Aircraft Flight Manual (AFM) by incorporating the following:

" Except for certain phases of flight where the AFM specifies that deicing boots should not be used (e.g., take-off, final approach, and landing), compliance with the following is required.

• Wing and Tail Leading Edge Pneumatic Deicing Boot System, if installed, must be activated:

-   At the first sign of ice formation anywhere on the aircraft, or upon annunciation from an ice detector system, whichever occurs first; and

-   The system must either be continued to be operated in the automatic cycling mode, if available; or the system must be manually cycled as needed to minimize the ice accretions on the airframe.

• The wing and tail leading edge pneumatic deicing boot system may be deactivated only after leaving icing conditions and after the airplane is determined to be clear of ice."

Alternatively, a copy of this Directive may be inserted in the Limitations Section of the Aircraft Flight Manual preceding the paragraph covering Operation in Icing Conditions.

This AFM amendment may be accomplished by the aircraft CoR holder, who can sign the aircraft logbook for completion of this Directive.

Note 1: Ice adhesion can be reduced by periodic treatment of deicing boots with a deicing compound such as “ICEX”, an ice-phobic chemical spray.

Note 2: FAA AD 2000-02-30 Amendment 39-11548 refers.

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Compliance: Within 10 calendar days’ time in service from the effective date of this Directive.

This Airworthiness Directive becomes effective on 13 July 2000.

Background:  This Directive is issued to ensure deicing boots are activated as soon as ice build up is detected. If this action is not taken flight crews may experience reduced controllability of the aircraft due to the aerodynamic effects of ice adhering to the aircraft prior to the first deicing cycle.

Eugene Paul Holzapfel

Delegate of the Civil Aviation Safety Authority 2 June 2000

The above AD is notified in the Commonwealth of Australia Gazette on 14 June 2000.