FUEL TANK SAFETY / EWIS CONTINUATION TRAINING

Transcription

1 FUEL TANK SAFETY / EWIS CONTINUATION TRAINING Q3 & Q Page 1 of 13

2 CONTENTS: 1 INTRODUCTION 2 Fuel Tank Safety 3 EWIS 4 Related Airworthiness Directives 5 Fire risk leads RAF to withdraw Sentry from operations Page 2 of 13

3 1. Introduction The purpose of this module is to refresh SFAR 88 & EWIS knowledge, other aircraft specific related information can be found in the relevant aircraft modules of this CBT package. This module also reminds us of the importance of CDCCL s and ALI s under SFAR Fuel Tank Safety Engineers are reminded that they should have received training in both phase 1 and phase 2 FTS. This is detailed in PART 145:- Phase 1 + Phase 2 + Continuation training: Personnel of the Part-145 approved maintenance organisation required to plan, perform, supervise, inspect and certify the maintenance of aircraft and fuel system components specified in paragraph A). If you have not received phase 1 training previously Altitude Global Engineering Bulletin 26-Gen-028 covers the phase 1 FTS Awareness syllabus and can be provided with a read and sign record. Please contact the Quality Department for details. Note: Phase 1 and Phase 2 equate to the same when detailed as level 1 and level 2. FAA Docket No FAA states:- Fuel tank explosions have been a constant threat with serious aviation safety implications for many years, Since Aircraft have been damaged or destroyed as the result of a fuel tank explosion. Two of the more recent explosions one involving a Boeing 747 (Trans World Airways (TWA) Flight 800) off Long Island, New York in 1996 and the other, a Boeing 727 explosion (Avianca Flight 203) in Bogota, Columbia in A statistical evaluation of these accidents has led the FAA to project that, unless remedial measures are taken, four more United States (U.S.) registered transport category airplanes will likely be destroyed by a fuel tank explosion in a 35 years period. Page 3 of 13

4 It is believed that at least three of these explosions are preventable by the adoption of a comprehensive safety regime to reduce both the incidence of ignition sources developing and the likelihood of the fuel tank containing flammable fuel vapours. The following elements were picked out as common parameters during a review of all the previous related incidents. The weather was warm, with an outside air temperature over 80 F The explosions occurred on the ground or soon after takeoff The explosions involved empty or nearly empty tanks that contained residual fuel from the previous fuelling. Investigators were able to conclude that the centre wing fuel tank in all three airplanes contained flammable vapours in the tank ullage In each case, an ignition source occurred that has not been positively identified. Therefore the following acronyms fell out of this review:- EZAP (Enhanced Zonal Analysis Programme) Required manufactures to re-examine the method by which they devise maintenance schedules to take into account electrical wiring and Fuel Tank Safety issues. EWIS Electrical Wiring Interconnection Systems CDCCL (Critical Design Configuration Control Limitations) Required manufactures to identify ALIs (Airworthiness Limitation Items) for their various aircraft types These Fuel Tank Safety (FTS) initiatives cover four main areas : Ignition Prevention - Wiring Segregation - Power Cables - Anti-ice/Bleed Air - ECS - Potential Ignition Sources in vapour areas Flammability Reduction. Maintenance Rules Instruction for Continued Airworthiness Page 4 of 13

5 Fuel system Airworthiness Limitations (AWLs) are mandatory maintenance actions required to ensure that unsafe conditions do not occur or are not introduced into the fuel tank system as a result of configuration changes, repairs, alterations, or deficiencies in the maintenance programme throughout the operational life of the aircraft. An AWL may be in the form of Airworthiness Limitation Instruction (ALI s) Or Critical Design Configuration Control Limitation Items (CDCCL s) What are ALI s? These are mandatory repetitive inspections which are required to help ensure that components which are subject to degradation or damage do not deteriorate to the point where they may fail and create an ignition source in the fuel tanks. Some examples of ALI s are verification of electrical bonding and inspection of wiring insulation, routing and clamping. CDCCL Critical Design Configuration Control Limitations identify the critical design features such as proper wire separation, proper installation of a panel gasket, minimum bonding jumper resistance levels, etc., that must be maintained in exactly the same manner throughout the life of the aircraft in order to comply with the type certificate and maintain airworthiness. The purpose of the Critical Design Configuration Control Limitation (CDCCL) is to provide instructions to ensure these critical features are present throughout the life of the airplane and are Inspected and verified when alterations, repairs, or maintenance actions occur in the area. CDCCL s must be accomplished in exactly the same manner as specified in the AMM Any use of parts, methods, techniques or practices different than what is written in the CDCCL must be approved. Any maintenance actions or subsequent changes to the product made by operators or the manufacturer MUST NOT DEGRADE the level of safety of the original type design. Page 5 of 13

6 Some useful Manufacturer information regarding inerting of fuel tanks. Airbus It is worth noting that Airbus deem that the A320 series use pressurised air which maintains the fuel tanks below the flammability level therefore negating the need to use a new inerting system such as nitrogen. Boeing Boeing installs the NGS system on all production 737NG, 767, 777, 787 and 747 airplanes. Installation of NGS was mandated by FAA rule for production airplanes starting in December This was accomplished on each airplane as noted below: 737NG All 737NG airplanes line position 2620 and on have a NGS system installed in production. Line number 2620 delivered in June All 767 airplanes line position 993 and on have a NGS system installed in production. Line number 993 delivered end of Aug All 777 airplanes from line position 772 and on have a NGS system installed in production. Line number 772 delivered in March All airplanes have a NGS system installed. 747 All airplanes will have a NGS system installed. Page 6 of 13

7 3. EWIS Electrical Wiring Interconnect System Simply described EWIS is the term used for the basic maintenance requirements of aircraft wiring and electrical systems, with respect to the maintenance and associated working practices, general care, inspection standards, safety, housekeeping and repair of all electrical items (including wiring) on an aircraft The actual term EWIS has been derived from documentation issued by EASA in order to address aircraft general Wiring Standards. EWIS covers the Maintenance of A/C wiring and electrical components Its Associated practices for wiring maintenance General care of wiring on and around A/C Maintenance Inspection standards General wiring safety General A/C and wiring housekeeping Repair Techniques General Wiring Standards Aircraft Improvements to reduce known problems EWIS was published by EASA by amendment 4 (ED Decision 2008/007/R of 29/08/2008) to AMC-20 General Acceptable Means of Compliance for Airworthiness of Products, Parts and Appliances. This document can be found via the following webpage. The amendment included the following headings:- AMC AMC AMC Programme to Enhance Aeroplane Electrical Wiring Interconnection System Maintenance Aeroplane Electrical Wiring Interconnection System Training Programme Development of Electrical Standard Wiring Practices Documentation This AMC was heavily based around maintenance providers and maintaining organisations with the emphasis being on enhancing maintenance procedures and inspection based on extensive research into aircraft wiring standards. Objective was to promote new Enhanced Zonal Analysis Procedures (EZAP). To ensure appropriate attention was given to aircraft wiring and its related maintenance.new Guidance for General Visual Inspections (GVI) and it touches on the issue of staff and their awareness and training New Guidance for General Visual Inspections (GVI) and it Page 7 of 13

8 Below are the target group categories as listed in Annex III to ED Decision 2008/007/R of 29/08/2008 AMC 20-22, Aeroplane Electrical Wiring Interconnection System Training Programme, including the tables referring to the depth of knowledge to be covered for each group. Target Group 1: Qualified staff performing EWIS maintenance. Target Group 2: Qualified staff performing maintenance inspections on EWIS. Target Group 3: Qualified staff performing electrical/avionic engineering on in-service aeroplane. Target Group 4: Qualified staff performing general maintenance/inspections not involving wire maintenance (LRU change is not considered wire maintenance) Target Group 5: Qualified staff performing other engineering or planning work on in-service aeroplane Target Group 6: Other service staff with duties in proximity to electrical wiring interconnection systems Target Group 7: Flight Deck Crew Target Group 8: Cabin Crew 4. Related Airworthiness Directives AD No.: Airworthiness Directives can be viewed at ATA 24 Electrical Power Wing Electrical Installation Modification Manufacturer/s: Airbus (formerly Airbus Industrie) Applicability Reason: Airbus A , A ST and A310 aeroplanes, all certified models, all manufacturer serial numbers. Following publication of FAA SFAR 88 (Special Federal Aviation Regulation 88), EASA issued AD requiring inspection and corrective action to improve the explosion risk protection system for the left hand (LH) and right hand (RH) wings on A300, A , A ST and A310 aeroplanes. For A , A ST and A310 aeroplanes, the required detailed visual inspections of electrical bundles located in the leading and trailing edges of the RH and LH wings and a review of the wing electrical installation on the final assembly line have shown that the wing electrical installation does not comply with the minimum distance inspection criteria to the surrounding structure in a few wing locations. Continued... Page 8 of 13

9 This condition, if not detected and corrected, could lead to damage on the electrical harnesses and on the surrounding structure. To address this unsafe condition, Airbus developed an improvement of the wing electrical installation to prevent possible chafing and subsequent damage to the electrical harnesses and surrounding structure. Consequently EASA issued AD to require installation of new bracket assemblies to ensure the clearance between the wiring and the structure, and installation of protective split sleeves as mechanical protection to the electrical harnesses. Since EASA AD was issued, during embodiment of Airbus Service Bulletin (SB) A Revision 02 on an aeroplane, an installation problem was identified, which prompted Airbus to revise SB A Revision 01, and A Revision 02. Service Bulletin Information Transmission (SBIT) Revision 01 dated 06 February 2015 recommended to postpone embodiment of these two SB s, and to wait for the availability of Airbus SB A Revision 02 and A Revision 03. EASA AD was issued to supersede EASA AD and required in addition, for the A and A ST aeroplanes only, installation of new bracket assemblies in shroud box (LH and RH side) to ensure adequate clearance between wirings and flap track carriage (LH and RH side). Since EASA AD was issued, some operators reported that Airbus SB A Revision 03 could not been implemented, due to missing installation information. Airbus supported the affected operators by providing the necessary installation information, and corrected Airbus SB A at Revision 04 to provide adequate installation information. For the reasons described above, this AD retains the requirement of the EASA AD , which is superseded, and requires additional work for certain A aeroplanes. Page 9 of 13

10 EASA AD US Airworthiness Directives can be viewed at ATA 28 Manufacturer(s): Chafing of the wire bundles inside the electrical conduit of the forward and aft boost pumps Boeing Applicability: The Boeing Company Model , B, B SUD, B, C, F, , , D, F, 747SR, and 747SP series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin A2306, dated October 2, Reason: This AD was prompted by several reports of chafing of the wire bundles inside the electrical conduit of the forward and aft boost pumps of the numbers 1 and 4 main fuel tanks due to high vibration. These wire bundles can chafe through the wire sleeving into the insulation, exposing the wire conductors. This AD requires replacing the wire bundles inside the electrical conduit of the forward and aft boost pumps of the numbers 1 and 4 main fuel tanks with new, improved wire bundles inserted into conduit liners. This AD also requires adding a revision to the maintenance or inspection program, as applicable, to include critical design configuration control limitations (CDCCLs) for the fuel boost pump wiring. We are issuing this AD to prevent chafing of the wire bundles and subsequent arcing between the wiring and the electrical conduit creating an ignition source in the fuel tanks, which could result in a fire and consequent fuel tank explosion. Page 10 of 13

11 EASA AD US Airworthiness Directives can be viewed at ATA 28 Manufacturer(s): Fastener type in the fuel tank walls has insufficient bond to the structure Boeing Applicability: The Boeing Company Model , D, and F series airplanes, certificated in any category, as identified in Boeing Special Attention Service Bulletin , Revision 1, dated July 27, Reason: This AD was prompted by a determination that a certain fastener type in the fuel tank walls has insufficient bond to the structure, and an electrical wiring short could cause arcing to occur at the ends of fasteners in the fuel tanks. This AD requires the installation of new clamps and polytetrafluoroethylene (TFE) sleeves on the wire bundles of the front spars and rear spars of the wings. This AD also requires inspecting the existing TFE sleeves under the wire bundle clamps for correct installation, and replacement if necessary. We are issuing this AD to prevent potential ignition sources in the fuel tank in the event of a lightning strike or highpowered short circuit, and consequent fire or explosion. Page 11 of 13

12 Flight Global story 08 November 2016 written by Beth Stevens. Fire risk leads RAF to withdraw Sentry from operations The Royal Air Force s Boeing E-3D Sentry airborne early warning aircraft have been temporarily removed from service, as a result of major issues with the platform s electrical and fire safety equipment. The Sentry fleet recently entered routine servicing, during which the type was categorised as unserviceable. This led to fleet-wide operations being put on hold. As a result of routine technical inspections on RAF E-3D Sentry aircraft, an issue has been identified relating to the integrity of some electrical wiring and cabin conditioning systems, the RAF tells FlightGlobal. Safety remains our paramount concern. Therefore, the UK Sentry fleet will only fly again once the ongoing rectification work is complete. While the air force could not go into further detail, sources claim that on inspection, it was found that wiring under the floor was arcing and old and in turn a fire risk while fire blankets were found to not be fireproof. The problems were identified a couple of weeks ago and had not previously been an issue, and an industry/air force team is now working to fix the faults and bring the aircraft back into service. No exact timeline for the E-3D s return to service have been revealed, but the problems are expected to be fixed in the coming weeks, an RAF source says. Gary Dawson/REX/Shutterstock Page 12 of 13

13 Sentry is supporting the RAF s operations in Iraq and Syria against Islamic State insurgents. Six examples are in service with the UK, Flight Fleets Analyzer shows, ranging between 25 and 27 years in age. Northrop Grumman provides the E-3D s APY-2 radar, and also heads a team that provides ongoing wholelife support of the fleet. The company was awarded an extension to the contract earlier this year, helping to keep the aircraft in service until a current planned retirement date of Northrop was unavailable for comment about the reported faults. A mission system mid-life upgrade will also be required to keep the fleet flying until It is expected to be put out to tender in mid END - Page 13 of 13