AIRWORTHINESS DIRECTIVE AIRWORTHINESS DIRECTIVE

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.

Beechcraft 55, 58 and 95-55 (Baron) Series Aeroplanes

AD/BEECH 55/90 KA-33 Cooling Blower 8/20 AD/BEECH 55/90 KA-33 Cooling Blower 8/2001

AD/BEECH 55/90 KA-33 Cooling Blower 8/2001

Applicability: Beech Model 58 and 58A aeroplanes, serial numbers TH-1436 through TH-1883 inclusive.

Requirement: 1. Inspect the aeroplane in accordance with Part I of the Accomplishment Instructions of Raytheon Mandatory Service Bulletin SB 34-3267, issued March 1999, to verify whether a KA-33 avionics cooling blower system is installed and operating correctly.

2. If the Requirement 1 inspection confirms that a KA-33 cooling blower is fitted, install a one ampere circuit breaker, part number 7277-2-1, in place of the factory installed three ampere or five ampere circuit breakers in accordance with Part II of the Accomplishment Instructions of SB 34-3267.

3. Three ampere or five ampere circuit breakers must not be installed on any aeroplane to protect the KA-33 cooling blower.

Note: FAA AD 2001-11-03 Amdt 39-12244 refers.

Compliance: For Requirement 1 - Within the next 600 hours time-in-service after the effective date of this Directive or the next six calendar months after the effective date of this Directive, whichever occurs first.

For Requirement 2 - Before further flight after the Requirement 1 inspection. For Requirement 3 - As of the effective date of this Directive.

This Airworthiness Directive becomes effective on 9 August 2001.

Background: The United States Federal Aviation Administration has received several reports of blower motors failing, seizing, smoking, and producing a burning odour that enters the cabin and passenger compartment. These events are the result of the blower motor having circuit protection of more than one ampere. This level of circuit protection does not prevent the blower motor from smoking and creating a burning odour should it fail or seize.