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 727 Series Aeroplanes
AD/B727/190 Electrical Bonding 8/2004
Applicability: Model 727-100 and -200 series aeroplanes as listed in Boeing Alert Service Bulletin (ASB) 727-29A0067 dated 7 June 2001.
Requirement: 1. Prepare the electrical bonding faying surfaces for the tubing penetrations of the hydraulic heat exchanger on the forward and aft surfaces of the rear spars of the fuel tanks of the left and right wings, together with carrying out a one-time measurement of the electrical bonding resistances between the penetration fittings of the hydraulic heat exchanger and the rear spars; and between the heat exchanger tube and the lower wing stringer surfaces, per the Accomplishment Instructions of ASB 727-29A0067.
2. If the bonding resistance is incorrect, repeat the preparation of the electrical bonding faying surface for the tubing penetrations of the hydraulic heat exchanger on the forward and aft surfaces of the rear spar of the fuel tanks of the left and right wings as necessary to achieve a bonding resistance below the threshold specified in the Accomplishment Instructions of ASB 727-29A0067.
3. Apply fillet sealant and protective finishes around the penetration fittings of the hydraulic heat exchanger in accordance with the Accomplishment Instructions of ASB 727-29A0067 (Figure 4 refers).
4. Service and pressurize the hydraulic systems and examine for signs of hydraulic fluid leakage. Service the fuel tank and examine for signs of fuel leakage. All these actions are to be accomplished in accordance with ASB 727-29A0067.
5. Repair any leaks found, during the Requirement 4 examination, in accordance with ASB 727-29A0067.
Note: FAA AD 2004-10-06 Amdt 39-13636 refers.
Compliance: For Requirement 1 - Within 60 months after the effective date of this Directive.
For Requirement 2 - Before further flight after the Requirement 1 bonding resistance check.
For Requirement 3 - Before further flight after completing Requirements 1 and 2.
Boeing 727 Series Aeroplanes
AD/B727/190 (continued)
For Requirement 4 - Before further flight after completing Requirement 3. For Requirement 5 - Before further flight after completing Requirement 4. This Airworthiness Directive becomes effective on 5 August 2004.
Background: This Directive requires, among other things, preparation of the electrical bonding faying surfaces for the tubing penetrations of the hydraulic heat exchanger on the forward and aft surfaces of the rear spars of the fuel tanks of the left and right wings, a one-time measurement of the electrical bonding resistances together with follow-on actions.
These actions are necessary to ensure adequate electrical bonding between the penetration fittings of the hydraulic heat exchanger and the rear spars of the fuel tanks. Inadequate electrical bonding, in the event of a lightning strike, could cause electrical arcing and ignition of fuel vapour in the wing fuel tank, which could result in a fuel tank explosion.
James Coyne
Delegate of the Civil Aviation Safety Authority 23 June 2004
The above AD is notified in the Commonwealth of Australia Gazette on 14 July 2004.
Overview
The Airworthiness Directive (AD) AD/B727/190 was issued by the Civil Aviation Safety Authority (CASA) in 2004 to address the problem of inadequate electrical bonding between the penetration fittings of the hydraulic heat exchanger and the rear spars of the fuel tanks in Boeing 727-100 and -200 series aeroplanes. This inadequacy, if left unaddressed, could lead to electrical arcing and the ignition of fuel vapour in the wing fuel tanks, potentially resulting in a fuel tank explosion in the event of a lightning strike. The AD requires specific actions, including the preparation of electrical bonding faying surfaces, measurement of bonding resistances, and application of fillet sealant and protective finishes, to ensure that the bonding resistances are below specified thresholds. The directive also mandates examinations and repairs for hydraulic and fuel system leaks. Compliance with these requirements is essential for maintaining the airworthiness of the affected aircraft, with specific timelines provided for each requirement. This AD was issued under subregulation 39.1 (1) of the Civil Aviation Safety Regulations 1998, reflecting CASA's commitment to ensuring aviation safety.
Scope and Application
The Airworthiness Directive (AD) issued by the Civil Aviation Safety Authority (CASA) under subregulation 39.1 (1) of the Civil Aviation Safety Regulations 1998 applies specifically to Model 727-100 and -200 series aeroplanes as identified in the Boeing Alert Service Bulletin (ASB) 727-29A0067 dated 7 June 2001. This legislation mandates certain actions to address an identified unsafe condition related to the electrical bonding of the hydraulic heat exchanger in the fuel tanks of Boeing 727 aeroplanes. The directive requires the preparation of electrical bonding faying surfaces, measurement of electrical bonding resistances, and the application of fillet sealant and protective finishes. If bonding resistances are found to be incorrect, remedial action must be taken before further flight. Additionally, hydraulic and fuel tank systems must be serviced and examined for leaks, with any detected leaks repaired before further flight. This AD is effective from 5 August 2004 and is applicable within the Commonwealth of Australia. The requirements must be met within specific timeframes as outlined in the directive, ensuring compliance with safety standards to mitigate the risk of fuel tank explosions due to inadequate electrical bonding.
Key Provisions
The Airworthiness Directive (AD) issued under subregulation 39.1 (1) of the Civil Aviation Safety Regulations 1998, mandates specific actions to correct an unsafe condition for Boeing 727 series aeroplanes. The AD, AD/B727/190, applies to Model 727-100 and -200 series aeroplanes as identified in Boeing Alert Service Bulletin (ASB) 727-29A0067 dated 7 June 2001. This directive necessitates the preparation of electrical bonding faying surfaces for the tubing penetrations of the hydraulic heat exchanger on the rear spars of the fuel tanks, along with a one-time measurement of the electrical bonding resistances (section 1). If the bonding resistance is found to be incorrect, the preparation must be repeated to achieve the specified bonding resistance (section 2). Additionally, fillet sealant and protective finishes must be applied around the penetration fittings of the hydraulic heat exchanger (section 3). Before further flight, the hydraulic systems must be serviced and pressurized, and the fuel tank must be serviced, with both actions checked for leaks (section 4). Any leaks found must be repaired (section 5).
This AD imposes specific obligations on the operators and owners of the affected aircraft. They must ensure that the electrical bonding faying surfaces are prepared, the bonding resistances are measured and, if necessary, remediated, and the specified sealants and protective finishes are applied. Furthermore, they must service and pressurize the hydraulic systems and the fuel tank, check for leaks, and repair any leaks found before the aircraft is flown again. These actions must be carried out in accordance with the instructions provided in the Boeing Alert Service Bulletin (ASB) 727-29A0067. Each requirement must be completed within specified timeframes, with some actions needing to be completed before further flight and others within 60 months from the effective date of the AD.
Failure to comply with the requirements of this AD may result in serious safety risks, including the potential for electrical arcing and ignition of fuel vapour in the event of a lightning strike, which could lead to a fuel tank explosion. Although specific penalties are not detailed in the AD, non-compliance with Airworthiness Directives can result in enforcement actions by the Civil Aviation Safety Authority (CASA). These actions may include fines, suspension of airworthiness certificates, and other regulatory sanctions. The severity of the penalties will depend on the nature and extent of the non-compliance and its impact on air safety.