COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Boeing 747 Series Aeroplanes
AD/B747/128
Amdt 1
Lower Lobe Lap Joints at Wing to Body Fairing 6/95
Applicability: Boeing Model 747 aircraft, Line Numbers 201 to 814 inclusive.
Requirement: 1. Conduct a visual inspection to determine all countersunk fastener locations in the upper rows of the following nominated lap splice areas;
a) B747-100, -200, -300, -400 and 747SR. Inspect from Body Station (BS) 741 - BS1000 at Stringers (S-) 34L, 34R, 39L, 39R, 44L and 44R and from BS1480 - BS1741 at S-34L, 34R, 40L and 40R.
b) B747SP from BS520 - BS1000 at S-34L, 34R, 39L, 39R, 44L and 44R and from BS1480 - BS1901 at S-34L, 34R, 40L, 40R and 46L.
2. For unmodified aircraft, conduct a High Frequency Eddy Current (HFEC) inspection for cracks around all countersunk fastener heads in the upper row of the nominated lap splice areas. Inspect in accordance with Boeing Alert Service Bulletin (ASB) 747-53A2312, Revision 2, Accomplishment Instructions Part I.A.
3. Modify the aircraft, in accordance with Boeing ASB 747-53A2312 Revision 2, Accomplishment Instructions Part II, by replacing the countersunk fasteners with protruding head fasteners.
4. For modified aircraft, at all locations where countersunk fasteners have been replaced, do a HFEC inspection in accordance with Boeing ASB747-53A2312, Revision 2, Accomplishment Instructions Part III.
Note: FAA AD 94-15-06 refers.
Compliance: 1. For unmodified aircraft, inspect in accordance with the full extent of the new Requirement 1 before 11 000 flights or before 1000 flights after 25 May 1995, whichever occurs later, unless previously inspected.
2. Initially inspect in accordance with the full extent of the new Requirement 2 before further flight after inspection in accordance with Requirement 1, unless previously inspected within the last 3000 flights before 25 May 1995.
Re-inspect at intervals not to exceed 4000 flights until modified in accordance with Requirement 3.
3. Modify the aircraft in accordance with Requirement 3 before 20 000 flights.
4. Initially inspect each modified area in accordance with Requirement 4 before 10,000 flights after the date of modification.
Re-inspect at intervals not to exceed 4000 flights.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Background: This Directive has been prompted by reports of cracking in the stringer 34 lap joint near the interface with the wing-to-body fairing. This condition, if not corrected, could result in an in-flight depressurisation of the aircraft. This Amendment reduces the number of aircraft to be inspected and widens the inspection area to include all lap splice upper rows under the wing to body fairing.
Overview
The Civil Aviation Regulations 1998, enacted by the Commonwealth of Australia, address various aspects of civil aviation safety, including the issuance of airworthiness directives to ensure the safety and airworthiness of aircraft. One such directive, AD/B747/128 Amendment 1, specifically targets Boeing 747 series aeroplanes. This directive was introduced in response to reports of cracking in the stringer 34 lap joint near the interface with the wing-to-body fairing, which could potentially lead to in-flight depressurisation. The directive aims to enhance the safety of these aircraft by requiring thorough visual inspections, high frequency eddy current inspections, and modifications to the fasteners in specified areas. The Civil Aviation Safety Authority mandates these measures to mitigate the identified risk and ensure compliance with safety standards.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105, under the Civil Aviation Safety Authority's schedule of Airworthiness Directives, mandates stringent inspection and modification protocols for certain Boeing 747 series aeroplanes. This directive applies to Boeing Model 747 aircraft within Line Numbers 201 to 814 inclusive, focusing on specific lower lobe lap joints at the wing to body fairing. The directive requires operators to conduct detailed visual inspections to locate all countersunk fasteners in designated lap splice areas, followed by high-frequency eddy current inspections for cracks, and subsequent modifications to replace the fasteners. These requirements are critical to preventing potential in-flight depressurisation due to structural integrity issues. Compliance timelines are set for inspections and modifications, with varying intervals based on the aircraft's modification status and flight hours. This regulatory framework ensures the continued safety and airworthiness of the specified Boeing 747 models operating within Australia's airspace.
Key Provisions
The Civil Aviation Safety Authority (CASA) has issued an Airworthiness Directive (AD) concerning the Boeing 747 series aeroplanes, specifically focusing on the lower lobe lap joints at the wing-to-body fairing. The directive, identified as AD/B747/128 Amendment 1, is applicable to Boeing Model 747 aircraft within certain line numbers (sections 1 and 2). This directive mandates that operators conduct a series of inspections and modifications to ensure the structural integrity of these specific areas of the aircraft.
The main operative sections of this directive (section 3) require operators to first conduct a visual inspection to identify all countersunk fastener locations in the upper rows of specified lap splice areas. Depending on the model of the aircraft, different body stations and stringers are to be inspected. Operators must also perform a High Frequency Eddy Current (HFEC) inspection for cracks around all countersunk fastener heads in the upper row of the nominated lap splice areas for unmodified aircraft. For aircraft that have not yet been modified, the countersunk fasteners must be replaced with protruding head fasteners. For those aircraft that have undergone the modification, an HFEC inspection must be performed in the modified areas.
Operators of Boeing 747 aircraft subject to this directive have specific obligations and requirements (section 4). For unmodified aircraft, a visual inspection must be conducted before 11,000 flights or before 1,000 flights after 25 May 1995, whichever is later, unless previously inspected. An HFEC inspection must be completed before further flight after the initial inspection, unless previously inspected within the last 3,000 flights before 25 May 1995. The modified areas must be inspected at intervals not to exceed 4,000 flights until the aircraft is modified. After modification, each modified area must be inspected before 10,000 flights, with subsequent inspections at intervals not exceeding 4,000 flights.
There are significant consequences for non-compliance with this directive (section 5). Operators who fail to adhere to the inspection and modification requirements outlined in this directive may face enforcement actions from CASA. While the specific penalties for non-compliance are not detailed in the directive, non-compliance with CASA regulations generally can result in enforcement measures, which may include fines, suspension of the operator’s licence, or other regulatory actions. Such penalties are intended to ensure that all aircraft meet the necessary safety standards to protect passengers and crew.