AIRWORTHINESS DIRECTIVE
For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/LJ45/4 and issues the following 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.
Learjet 45 Series Aeroplanes
AD/LJ45/4
Amdt 1
Cockpit Foot Warmer 3/2004
Applicability: Model 45 aeroplanes, serial numbers 45-005 through 45-213 inclusive.
Requirement: 1. Unless already accomplished in accordance with AD/LJ45/4 original issue, pull (open) the FOOT WARM circuit breaker, located on the copilot's circuit breaker panel, and install a collar on the FOOT WARM circuit breaker, per Bombardier Aerospace Learjet Alert Service Bulletin SB A45-21-14, dated 3 May 2002.
2. Reactivate the foot warmer system by removing the collar and closing the FOOT WARM circuit breaker.
Note 1: FAA AD 2002-17-01 Amdt 39-12866 and FAA Small Airplane Directorate Alternate Method of Compliance (AMOC) letter dated 5 November 2003 refer. The FAA AMOC letter is included in Bombardier Aerospace Advisory Wire 21-006.
Compliance: For Requirement 1 - As of the effective date of this Amendment.
For Requirement 2 - Following the optional replacement/modification of the pilot and co-pilot heel plate assemblies in accordance with Bombardier Aerospace Learjet Service Bulletin SB 45-21-15.
Note 2: SB 45-21-15 requires either concurrent or prior incorporation of SB45-21-2 on aeroplanes serial numbers 45-001 through 45-119.
This Amendment becomes effective on 18 March 2004.
Background: The United States Federal Aviation Administration has received reports of smoke in the cockpit caused by electrical short circuits between the pilot's and copilot's foot warmers and the composite floorboards. A short circuit in a foot warmer causes electrical current to flow through the metal heelplate of the foot warmer to the composite floorboards. Due to the high resistance of the composite floorboards, the circuit breaker may not open, or the opening could be significantly delayed, which could result in outgassing of the faceply material of the composite floorboards, and consequent smoke in the cockpit.
The original issue of this Directive required pulling the FOOT WARM circuit breaker and installing a collar on that circuit breaker.
Learjet 45 Series Aeroplanes
AD/LJ45/4 Amdt 1 (continued)
This amendment introduces an optional terminating action to the deactivation of the cockpit foot warmer system.
` The original issue of this Airworthiness Directive became effective on 18 September 2002.
James Coyne
Delegate of the Civil Aviation Safety Authority 22 January 2004
The above AD is notified in the Commonwealth of Australia Gazette on 25 February 2004.
Overview
The Civil Aviation Safety Authority (CASA) has issued Airworthiness Directive (AD) AD/LJ45/4 Amendment 1, which pertains to Learjet 45 series aeroplanes with serial numbers 45-005 through 45-213 inclusive. This AD addresses a safety issue identified in the United States Federal Aviation Administration reports of smoke in the cockpit caused by electrical short circuits between the pilot's and copilot's foot warmers and the composite floorboards. The directive aims to correct this unsafe condition by requiring the deactivation of the cockpit foot warmer system and providing an optional step for reactivating it following the modification of the heel plate assemblies. This AD was introduced to ensure the continued airworthiness of the specified aircraft models by mitigating the risk of electrical short circuits that could lead to smoke in the cockpit.
The AD was enacted under subregulation 39.1(1) of the Civil Aviation Safety Regulations 1998, with the objective of ensuring that the necessary safety measures are implemented to address the identified risk. The directive became effective on 18 March 2004, following its notification in the Commonwealth of Australia Gazette on 25 February 2004. The CASA delegate, James Coyne, signed the directive on 22 January 2004, signifying the authority's commitment to maintaining high safety standards within the aviation industry.
Scope and Application
The Airworthiness Directive issued by the Civil Aviation Safety Authority (CASA) under the Civil Aviation Safety Regulations 1998 applies specifically to Learjet 45 series aeroplanes with serial numbers ranging from 45-005 through 45-213 inclusive. This directive mandates corrective action regarding the cockpit foot warmer system to rectify an unsafe condition identified due to potential smoke generation from electrical short circuits. The requirement involves opening the FOOT WARM circuit breaker and installing a collar on it, following Bombardier Aerospace Learjet Alert Service Bulletin SB A45-21-14, dated 3 May 2002. The directive also allows for the re-activation of the foot warmer system under specific conditions, such as the replacement or modification of the pilot and co-pilot heel plate assemblies in accordance with Bombardier Aerospace Learjet Service Bulletin SB 45-21-15. This AD extends across the Commonwealth of Australia and is effective as of 18 March 2004, with compliance necessitated at the specified times for each requirement. The directive is intended to address safety concerns identified by the United States Federal Aviation Administration, and it references relevant FAA advisories for further guidance.
Key Provisions
The Airworthiness Directive (AD) AD/LJ45/4 Amdt 1 (section 3) addresses specific safety concerns related to the cockpit foot warmer system in Learjet 45 Series aeroplanes, particularly those with serial numbers ranging from 45-005 to 45-213 inclusive (section 3). The directive requires two main actions. Firstly, unless already completed according to the original AD/LJ45/4, the FOOT WARM circuit breaker on the copilot's circuit breaker panel must be pulled (opened), and a collar must be installed on the FOOT WARM circuit breaker as per Bombardier Aerospace Learjet Alert Service Bulletin SB A45-21-14 dated 3 May 2002 (section 3). Secondly, the foot warmer system must be reactivated by removing the collar and closing the FOOT WARM circuit breaker (section 3). The first action must be taken as of the effective date of the Amendment, while the second action can be performed after the optional replacement or modification of the pilot and co-pilot heel plate assemblies, in accordance with Bombardier Aerospace Learjet Service Bulletin SB 45-21-15 (section 3).
The AD imposes specific obligations on the operators of the affected aircraft, requiring them to follow the instructions outlined in the requirement section of the directive (section 3). Operators must ensure that the FOOT WARM circuit breaker is pulled and a collar installed on the breaker unless these actions have already been completed as per the original AD/LJ45/4. Additionally, the re-activation of the foot warmer system must occur following the specified modifications to the heel plate assemblies (section 3). The AD also references relevant FAA documents and alternate methods of compliance to provide operators with additional guidance (section 3).
Failure to comply with the requirements of this AD may result in serious safety risks, including the potential for smoke in the cockpit due to electrical short circuits between the foot warmers and composite floorboards (section 3). While the AD does not explicitly state specific penalties for non-compliance, failure to adhere to such safety directives can lead to severe consequences, including the potential for grounding of the aircraft, enforcement actions by the Civil Aviation Safety Authority (CASA), and civil or criminal liability under broader aviation safety legislation (section 3). The AD came into effect on 18 March 2004, and its notification was published in the Commonwealth of Australia Gazette on 25 February 2004 (section 3).