CERTFICATION OF ENGINE HUMS ON MILITARY AIRCRAFT

Transcription

1 CERTFICATION OF ENGINE HUMS ON MILITARY AIRCRAFT Paul R. Parolo Squadron Leader Engine Structural Integrity Directorate General Technical Airworthiness, Australia ABSTRACT In recent years, the Australian Defence Force (ADF) has acquired aircraft that are factory fitted with advanced Health and Usage Monitoring Systems (HUMS). When HUMS are prescribed by the engine manufacturer as executive lifing tools for managing engine critical parts, the HUMS forms a part of the engine certification basis and needs to be validated with the same level of rigour that is applied to the rest of the aircraft. Due to a lack of civil and military airworthiness design requirements for HUMS equipment, the Australian Defence Force (ADF) has been required to develop a systematic process to enable certification of aircraft and engine HUMS equipment. This paper discusses the rapidly evolving technologies that the ADF must be aware of and understand when certifying modern HUMS equipment and summarises an in-service validation process developed by the ADF Directorate General Technical Airworthiness (DGTA). The paper uses the BAE SYSTEMS Hawk (Mk 115 and Mk 127) HUMS as a case study with a focus on the engine usage monitoring function. BACKGROUND The ADF is responsible for issuing an Australian Military Type Certificate (AMTC) for each state operated aircraft type. One of DGTA s key responsibilities is to recommend to the ADF Airworthiness Authority (AA) (being Chief of Air Force), whether a new aircraft type should receive an AMTC from a technical design and in-service support perspective. One of the major technical requirements for an AMTC is that compliance with an agreed certification basis needs to be demonstrated by qualified organisations, who must consider the applicability of proposed design standards to the planned ADF configuration, role and environment (CRE). A certification basis is a comprehensive set of design requirements against which an aircraft s technical airworthiness may be assessed [1]. DGTA sponsors the ADF Airworthiness Design Requirements Manual (ADRM) which provides guidance for an acquisition Project Office (PO) when developing an aircraft specification by listing preferred design standards to enable comparative assessments. The ADRM is being further developed to address certification of aircraft and engine health and usage monitoring systems (HUMS) to assist POs in the future. DGTA also sponsors the Technical Airworthiness Management Manual (TAMM) which includes certification regulations that must be complied with prior to issue of an AMTC. TAMM Regulation requires Authorised Engineering Organisations (AEO) to develop an Engine Structural Integrity Management Plan (ESIMP) which is similar to DEF STAN and JAR-E requirements for an engine Life Management Plan (LMP). Key contents of the ESIMP include: designation of an engine structural integrity manager, a description of the engine and its certification basis, recognition of engine critical parts and their life limits, a description of the usage monitoring system, and in-service activities required for continued airworthiness such as regular reviews of ADF engine usage data. INTRODUCTION Engine critical parts (which upon failure could cause loss of aircraft) experience a combination of thermal and mechanical stresses sometimes referred to as thermo-mechanical stresses. Mechanical stresses are caused by interference fits during engine build up, aerodynamic loads and pressure forces but are predominantly caused by centrifugal loads. Thermal stresses are prevalent in turbine discs, which experience significant temperature differentials between the hot disc rim and the relatively cool centre bore particularly during transient conditions. High thermo-mechanical stresses occur during engine start up and shut down, which is referred to as a full (or major) Low Cycle Fatigue (LCF) cycle since it is a cycle that causes relatively high stress and occurs at low frequency. Less severe partial (or minor) LCF cycles are produced during throttle transients experienced during operations such as air Copyright of this document retained by author(s) and corporate author. Compilation copyright Commonwealth of Australia. HUMS 2003 Conference 506-1

2 combat manoeuvring, formation flying or training for recovery from auto-rotations for helicopter aircraft. Early design of gas turbine engines confirmed the mechanical integrity of rotating critical parts through overspeed testing [2]. Whilst current design standards still require overspeed tests (up to 130% maximum rpm for United States Air Force [USAF] testing of titanium discs [3]), they have evolved to cater for the phenomenon of fatigue caused by repeated stress loadings that are less than the ultimate strength of a component. Stress conditions experienced in-service vary according to operating conditions, which are dictated by the operating role and environment for the parent aircraft. Traditionally, engine designers have needed to rely upon assumed in-service operating conditions, which is difficult for combat aircraft that require a significant number of throttle transients per mission flown. Quite often military aircraft are operated in a more severe manner than that assumed in design, which has led to significant lifing reductions and disruptions to aircraft operations for numerous operators including the RAAF and United States Navy (USN). In the worst cases, inaccurate design assumptions have led to component failures and loss of aircraft for civil and military operators [4]. Traditionally highly stressed critical parts have demonstrated poor resistance to crack propagation (ie fracture toughness) and have relied on statistical derivation of safe life LCF limits to achieve desired levels of safety. This is typically a 1/750 probability of crack initiation (0.76 mm surface crack) with a 95% confidence level (CL) 1. Safe life limits do not utilise any of the crack propagation life that may be available in a component but it has ensured that in-service failures are rare [2]. Military and civil design standards quickly evolved in the 1970s to ensure that engine lifing followed a disciplined and systematic process and that improved materials and designs with better resistance to crack propagation are used. Current civil and military design standards (such as FAR33 and DEF STAN respectively) assure continued airworthiness by specifying that the original engine manufacturer (OEM) must regularly review actual in-service data to validate design assumptions and confirm the applicability of life limits [5, 6]. Regardless, the engine lifing process is not an exact science [7] and remains a complex activity requiring detailed materials analyses, thermal modelling, stress modelling and mission analyses, verified by components and engine tests addressing all of which is not the aim of this paper. The process is typically based on engine OEM corporate policies and processes that have been evolving since the 1950s with varying levels of guidance in design standards, advisory circulars and military handbooks. 1 The basis of safe life limits will vary according to engine OEM and could be 1/1,000 with 95% CL (or B.1 in US parlance) or 1/10,000 with a 90% CL for Rolls-Royce North America (previously Allison Engines). Fitment of modern HUMS equipment makes in-service review of actual usage data a more accurate and automated process. Fleet-wide installation will accurately demonstrate the variations in fatigue life accrual, that occurs between aircraft in a fleet even when flying the same mission. Rolls-Royce demonstrated variations of up to 40 times more fatigue cycles between lead and tail aircraft for the Red Arrows diamond nine formation [8]. Their early studies led to the development of advanced systems that enable accurate calculations of damage accrual based on operating conditions experienced during every mission. Without fleet-wide installation of advanced usage monitoring systems, conservative assumptions need to be applied to cater for the variation in LCF cycle accrual, which results in some components being retired well before they actually reach their safe life limit. Economically this is undesirable since critical parts are some of the most expensive fitted to gas turbine engines. Experience by the German Air Force on Tornado RB199 engines has shown that fleet-wide installation of usage monitoring systems can more than double the available life for engine critical parts [9]. For the RAAF, variations in LCF accrual is expected between engines fitted to Hawk aircraft operated by 79 Squadron (SQN) at Pearce Western Australia and 76 SQN at Williamtown New South Wales. 79 SQN predominantly uses the Hawk for student pilots to convert from the turboprop PC-9/A whilst 76 SQN predominantly uses the Hawk for the Introductory Fighter Course (IFC) prior to conversion to F/A-18 or F-111 aircraft. Hence fleet-wide HUMS installation to RAAF Hawk aircraft is an optimal solution in terms of utilising all of the fatigue life available on engines (and airframes). Whilst it remains impractical to fit strain gauges to engine components in-service, the lifing process will always rely on algorithms to calculate fatigue damage accrual based on processing engine and flight data. However, state of the art HUMS technology is taking some of the blackness out of the black art that engine lifing is often perceived as by providing engine designers with accurate in-service usage information to enable validation of design assumptions. The process of reviewing in-service usage data needs to be formally documented in a plan such as an ESIMP. Furthermore, inservice validation of HUMS equipment is required to enable initial certification and assure continued airworthiness of critical parts (and critical aircraft structure). ADF ENGINE USAGE MONITORING SYSTEMS Usage monitoring requirements for ADF aircraft vary according to the OEM requirements that are typically dictated by the aircraft application and the level of technology available at the time of service introduction. The following summarises the different engine usage monitoring systems that exist (as documented by each engine type s ESIMP): a. LCF hourly limits for an engine without a cycle counter. The OEM limits are based on an assessment HUMS 2003 Conference

3 of operator mission profiles and are derived using OEM conversion factors not visible to the operator. The operator manually tracks hours only (eg F-111 TF30 engine). b. LCF cyclic limits for an engine without a cycle counter. The operator has an option to manually track cycles or hours and derive a suitable conversion factor(s) to convert flight hours to cycles (eg C-130H and P-3 T56 engines, Iroquois T-53 engines, Sea King Gnome engines). c. LCF cyclic limits for an engine without a cycle counter but which requires use of a simple algorithm to track events such as number of starts and excursions to emergency power settings. The operator has to manually track these events and calculate LCF cycle accrual (eg Squirrel Arriel1B engines, Chinook T-55 engines). d. LCF cyclic limits for an engine with a cycle counter. The operator is required to keep track of LCF cycle counts accrual (Seahawk/Seasprite T700 variants) or there may be an automated ground based system to perform the cycle tracking function (eg C-130J-30 AE2100D3 engine). e. Equivalent LCF (ELCF) cycle limits for an engine with a simple electronic cycle counter. The operator is required to record major, partial and start cycles then use a simple algorithm that accommodates operator mission severity using damage factors. (eg Black Hawk T700 engine variant). f. ELCF cycle limits for an engine with a more complex electronic cycle counter and automated process for calculating ELCF counts using an algorithm that accommodates the operator s unique mission severity using specific damage or k factors. The airborne system may be supplemented with a ground based Parts Life Tracking System (eg F/A-18 F404 engine). g. LCF Thermal Transient Cycle (TTC) limits requiring a complex lifing program that uses heat transfer coefficients to determine real time damage accrual caused by thermo-mechanical stress conditions experienced during every flight (eg BAE SYSTEMS Hawk Adour engine). The latter and most advanced example of the ADF engine usage monitoring systems, has required the ADF to catch up with industry in terms of understanding state of the art HUMS technology and being confident with certifying such a system. The HUMS fitted to the Hawk aircraft is the most elaborate of all ADF aircraft and is required for automatic calculation and tracking of fatigue life on critical aircraft structure and engine critical parts. There is no other means for calculating and tracking TTCs for Adour critical parts and hence, Rolls-Royce refers to the HUMS as the executive lifing tool for the Adour engine. As a result, unlike the majority of engine usage monitoring systems required for all other ADF aircraft, the BAE SYSTEMS Hawk HUMS forms a part of the certification basis for the Rolls-Royce Adour engine and requires an appropriate level of rigour during the certification compliance finding activity. BAE SYSTEMS HAWK HUMS The BAE SYSTEMS Hawk HUMS consists of the following components [10]: airframe strain gauges, airframe and engine sensors, an airborne flight data recorder (FDR) an airborne Data Acquisition Unit (DAU), a ground based Desk Top System (DTS), and a Flight Line System (FLS). The FLS is based on a ruggedised notebook computer and is used to download flight recorded data and Built-In-Test (BIT) results from the DAU for display on the DTS. The FLS stores up to 53 DAU downloads, three of which are OLM aircraft 2 and 40 usage mode flights can be stored for each aircraft. Once 40 usage flights for a single aircraft have been stored, the data must be transferred to the DTS. The FLS can also be used to upload software programmable parameters to the DAU such as engine and airframe fatigue limits and exceedence thresholds. The DAU, FMS and DTS are used by the Fatigue Management System (FMS) and the Engine Monitoring System (EMS), which are required for airframe and engine fatigue life management respectively. Airframe usage monitoring is achieved by recording and processing data from strain gauges mounted at key locations within the aircraft. Engine usage monitoring is conducted by the sampling and processing of engine and flight parameters. All engine parameters are sampled at a rate of 8Hz for processing by the DTS. Figure 1 briefly illustrates the system architecture for the major components in the Hawk HUMS. For the sake of comparing system architecture, the Lockheed Martin Aeronautics Systems (LM Aero) C-130J-30 aircraft HUMS consists of the following components [12]: airframe and engine sensors, an airborne Nacelle Interface Unit (NIU) for each engine, a Ground Maintenance System (GMS), and 2 Operational Loads Monitoring (OLM) aircraft are used to gather additional data for detailed analysis of in-service usage on the airframe. HUMS 2003 Conference 506-3

4 a removable memory module (RMM) card (which is inserted in a slot on the flight deck) for transferring data from the aircraft NIUs to the GMS. These components are used by the Structural Health Monitoring System (SHMS) and the Engine Monitoring System (EMS) for airframe and engine fatigue life management respectively. Whilst strain gauges are fitted to the C-130J-30 airframe, they are not required by the SHMS and are not yet certified for use by the airframe OLM system. Figure 2 briefly illustrates the system architecture for the major components in the C-130J-30 HUMS demonstrating some similarity with the Hawk system. The functions of each are quite different however, due to the different applications (military transport verses a more highly stressed combat trainer). The C-130J-30 system has the advantage of using a RMM card in each aircraft which can be quickly removed and replaced between flights, whereas the Hawk HUMS requires the FLS laptop to be connected to the aircraft to download HUMS data between flights. The Hawk HUMS download process can be timeconsuming if data from several flights and OLM aircraft needs to be downloaded. Rolls-Royce Adour Engine. There are ten critical parts on the Hawk engine (referred to by Rolls-Royce as Group A components) such as compressor and turbine rotating components, turbine discs and the combustion chamber outer casing. A total of 23 critical locations across the 10 critical parts are tracked by the EMS. Engine lifing program. Due to the computing power required, a Rolls-Royce proprietary lifing program is embedded in the DTS ground station. The DAU collects raw data sets based on six parameters being; turbine gas temperature (TGT), high pressure spool speed (NH), low pressure spool speed (NL), outside air temperature (OAT), indicated airspeed (IAS) and altitude (ALT). The raw data files are processed by the lifing program, which uses heat transfer coefficients pre-determined by a Rolls-Royce mainframe algorithm. The lifing program computes thermo-mechanical stresses for each data sample and then extracts maximum and minimum stress cycles. Finally it uses a damage summation algorithm to calculate the resulting fatigue damage accrual and the life remaining for each of the 23 critical locations across the 10 critical parts. The lifing program is also capable of monitoring non-critical locations in case they become critical during the service of the engine. Flight data sensors (OAT, ALT, IAS) DAU Airframe strain gauges Engine sensors (TGT, NH, NL) FDR FLS DTS Figure 1. Hawk HUMS Basic system architecture HUMS 2003 Conference

5 Flight data sensors Engine sensors NIU RMM GMS Figure 2. C-130J HUMS Basic system architecture COMMONWEALTH INDEPENDENT VERIFICATION AND VALIDATION The BAE SYSTEMS Hawk (Mk 115 & 127) 3 HUMS is state of the art in that it has fully integrated health and usage functions and has the capability to allow accurate calculation of airframe and engine life consumption. However, this capability and the procedures required to support it require thorough in-service validation. Since the Commonwealth did not contract for an inservice validation activity, Commonwealth Independent Validation and Verification (CIV&V) was required. The FMS and EMS components of the Hawk HUMS were validated under separate tasks managed by the Aircraft Structural Integrity (ASI) and Engine Structural Integrity (ESI) sections at DGTA. ASI and ESI utilised specialist resources at the Defence Science Technology Organisation (DSTO) and Ball Solutions Group (for the EMS). ESI was also required to task QinetiQ in the United Kingdom (UK) to gain an understanding of the Adour engine lifing methodology, algorithms and programs developed by Rolls-Royce. QinetiQ was formerly a 3 The BAe Hawk Mk 115 is operated by the Canadian Air Force, the Mk 127 is operated by the RAAF. component of the UK Defence Evaluation and Research Agency (DERA). They needed to be engaged to enable access to Rolls- Royce intellectual property (IP) held in the UK. QinetiQ results. Through tasking QinetiQ, it was learnt that the Adour lifing algorithms and DTS lifing program are used by Rolls-Royce to manage Group A components on all Royal Air Force (RAF) Rolls-Royce engines. This immediately raised the confidence of the ADF in the lifing algorithms and program in the DTS. Whilst the ADF was never in doubt of the engine OEM s capabilities, ADF lack of knowledge in state of the art HUMS equipment and lifing algorithms drove the QinetiQ task. Following a thorough review by QinetiQ of the; Adour lifing process, lifing algorithms, DTS lifing program and in-service management requirements, the ADF had further confidence in the EMS. However, additional confidence was required in the operating procedures, particularly for managing significant events such as invalid or missing data and reported exceedences (engine TGT, NH, NL and airframe Nz). Furthermore, resolution of technical queries relating to errors reported by the DTS was required. Functionality and procedural evaluation. The functionality of the overall system and the suitability of operating procedures HUMS 2003 Conference 506-5

6 was reviewed by DSTO and Ball Solutions Group. Due to limitations in ESI resources, Ball Solutions Group was tasked to coordinate the IV&V activity for the EMS and to assist with the review of the Adour ESIMP due to their corporate knowledge and experience with this type of documentation. Additional to HUMS deficiencies tracked by BAE SYSTEMS, Ball Solutions Group developed and maintained an Issues Log, which kept track of some 40 technical queries raised for Rolls-Royce and/or AMS, some of which require resolution before removal of an Interim Fatigue Life (IFL) limit of 800 engine hours. DSTO was used to perform data integrity and damage summation end-toend testing, using data sets provided by operating units and processing this data on site at Fishermans Bend Melbourne, using a DTS borrowed from BAE SYSTEMS. DSTO also compared in-flight manually recorded data from aircrew, at different points of a basic mission profile with HUMS reported data as a functional check. The Hawk HUMS was designed by Aerospace Monitoring Systems (AMS) Pty Ltd in South Africa to meet the requirements of the airframe and engine OEMs. Hence, lead times needed to be anticipated for any technical queries to be processed through a lengthy communication channel between Commonwealth agencies and OEM offices in Australia and overseas. The lack of contractual arrangements between the Commonwealth and aircraft sub-contractors added significant lead time to the Commonwealth IV&V activity and needs to be considered for future aircraft acquisitions. Engine Maintenance Guarantee. The RAAF has an Engine Maintenance Guarantee (EMG) contract with Rolls-Royce similar to a commercial power by the hour contract. Under the EMG, the RAAF pays Rolls-Royce an hourly rate which was based on planned engine usage rates agreed upon when the EMG was struck. Operational usage severity is indicated by component Cyclic Exchange Rates (CERs) which can be used to convert TTC limits into hourly limits to demonstrate the rate at which the operator is consuming fatigue life on critical components. The EMG requires that the actual RAAF CERs be calculated annually and compared with the planned CER threshold specified in the EMG in order to determine if any adjustments are required to the EMG payments. Since the CERs are also required to calculate fill-in factors when usage data is corrupt or missing, a regular analysis is also required for engine fatigue life management as stipulated in the ESIMP. Hence for the Hawk engine, the HUMS becomes an important tool from a fatigue life management perspective and a contractual management perspective. HUMS VERIFICATION PLAN Based on extant guidance in the ADRM (Section 2) and from experience gained during Commonwealth IV&V of the Hawk HUMS, a generic HUMS Verification Plan (HUMS VP) has been developed by ASI and ESI staff, which will become a requirement for future aircraft acquisitions beginning with the Air to Air Refueller (AAR) aircraft. A template will be provided in the next amendment to the ADRM to enable certification of a HUMS as suitable for the ADF. The minimum activities required by the HUMS VP are as follows: System design review of: Component specifications Software design standards Electromagnetic compatibility design standards Environmental design standards Lifing algorithms validation Data sampling rates Fill-in factors applicability Functional evaluation of: Review of OEM and ADF test reports In-service functionality checks Raw data integrity checks Lifing database and storage checks Configuration changes tracked Airframe Operational Loads Monitoring Calibration of sensors and strain gauges Integration with ADF management systems: Desirable but requires verification Procedures evaluation for: Data flow management Calibration of strain gauges and sensors Software upgrades Management of reported unserviceabilities Management of significant events such as invalid, missing and exceedence data Use of fill-in factors for invalid/missing data Database management security, backup and archiving CONDITION MONITORING PROGRAMS The ADF encourages engine condition monitoring (CM) programs but does not currently mandate them under extant TAMM Regulations. Guidance for developing engine CM programs is contained in the aircraft maintenance manual (AMM). It is acknowledged however that management of engines designed for an on-condition maintenance philosophy requires effective CM programs to ensure that engine condition or health is monitored (using OEM procedures and serviceability limits) to enable maintenance to be carried out before in flight shut down/failure. Whilst a modern HUMS is capable of providing a significant amount of health monitoring data such as time histories of engine temperatures, pressures, and spool speeds, as well as exceedence data, an efficient and disciplined process is required to make a CM program effective. Whilst the Hawk HUMS has a health monitoring function and can provide data that that would be suitable for trending engine condition, a formal engine CM program is yet to be HUMS 2003 Conference

7 developed but should be considered by BAe before the engines begin to degrade with normal usage. FUTURE HUMS VALIDATION REQUIREMENTS Future ADF aircraft acquisitions that are likely to be factory fitted with HUMS equipment include the: Armed Reconnaissance Helicopter (Eurocopter Tiger) ANZAC Ship Helicopters (SH-2G Super Seasprite) Airborne Early Warning and Control (AEW&C) aircraft. Air to Air Refueller (AAR) aircraft. New Air Combat Capability (NACC) aircraft. Similar to the Hawk and the C-130J-30 aircraft, the Commonwealth did not specify HUMS design standards for the first three aircraft listed above. There was also no requirement for the Contractor to perform in-service validation of a HUMS should it be factory fitted ie delivered as part of the aircraft baseline configuration. Hence, Commonwealth IV&V of HUMS equipment and procedures may be required for the Eurocopter Tiger, Super Seasprite and AEW&C aircraft, particularly if the delivered HUMS forms a part of the certification basis of the engine (and/or airframe) as was the case for the BAE SYSTEMS Hawk. Should the Commonwealth choose the JSF aircraft to meet NACC project requirements, it will utilise unprecedented HUMS technologies. The JSF aircraft has been mandated to have an alternate engine; either the Pratt and Whitney (P&W) F- 135 or the General Electric (GE) F-136. Both engine options are required to be fitted with a Prognostic and Health Monitoring System (PHMS). A PHMS is required to achieve single engine aircraft attrition rates comparable or better than an earlier 4 th generation twin engine aircraft such as the F/A-18E to meet United States Navy requirements [12]. The JSF PHMS will have an unprecedented capability to trend engine parameters in flight to provide real time engine condition monitoring. It will be able to detect and identify faults known to occur on military gas turbine engines. Following fault detection and identification, the PHMS will then predict a safe period of operation after which ground maintenance will be required and be arranged for by an integrated logistics management function before landing. Spare parts are ordered automatically by an Autonomic Logistics system. For the PHMS to achieve its required capability of fault identification, fault diagnosis and prediction of safe operating periods for all typical engine faults, a complex integration of advanced engine sensors and the following monitoring systems will be necessary [13]: Eddy Current blade Sensor (ECS) Ingested Debris Monitoring System (IDMS) Engine Distress Monitoring System (EDMS) Oil Debris Monitor (ODM) Electrostatic Bearing Monitor (EBM) Electrostatic Oil Debris Monitor (EODM) Oil Condition Monitor (OCM) The ECS is required at the fan inlet to mitigate High Cycle Fatigue (HCF) concerns for the fan discs that will be fitted to the JSF engines. Large integrally bladed rotors (IBRs in P&W parlance) or bladed disks ( blisks in GE parlance) are prone to HCF following foreign object damage (FOD) [14]. Ideally the RAAF would acquire a 5 th generation aircraft such as the JSF following certification and in-service validation by a major lead customer such as the United States Air Force (USAF). Depending on USAF and RAAF preferred service introduction dates this may not be possible. Regardless, it behoves the ADF to ensure that there is a contractual requirement for in-service validation of the PHMS to ensure the single engine attrition rates advertised by the aircraft OEM. To ensure that this activity is performed efficiently, it would be of benefit for the ADF to have a direct agreement with the engine OEM, additional to the aircraft prime contractor. This will minimise the lead times associated with certifying the engine and related systems. Furthermore, combat engines are the most susceptible to engine lifing reductions since they are operated so close to the limits of material capabilities. Formal agreements between the Commonwealth and engine OEMs have proven essential for combat aircraft (such as F-111 and F/A-18A), when managing engine lifing reductions that have caused major disruptions to aircraft operations. CONCLUSION This paper has discussed how usage monitoring systems have evolved to enable accurate calculations of engine (and airframe) fatigue life consumption and can be used to support engine condition monitoring programs. In some cases, such systems become a part of the aircraft certification basis and therefore require a rigorous compliance finding activity. For the Hawk aircraft, the HUMS also provides important functions for the Engine Maintenance Guarantee (EMG) contract. Currently DGTA ASI and ESI sections are required to manage Commonwealth IV&V activities for HUMS equipment fitted to Hawk and C-130J-30 aircraft. Through experience with the Hawk, an in-service validation process has been developed for future contractors to follow in accordance with a delivered HUMS Verification Plan. Certification schedules need to consider the lead times associated with processing technical queries generated by a HUMS compliance finding activity through multiple organisations. In the case of an engine monitoring system, it would be ideal if the ADF had a direct agreement with the HUMS 2003 Conference 506-7

8 engine OEM to minimise response turn around times and to assure efficient OEM support in times of engine lifing reductions. In the future, the ADF will need to ensure that a level expertise is retained in country to keep pace with rapidly evolving HUMS technologies such as the Prognostic Health Monitoring System (PHMS) to be fitted to Joint Strike Fighter (JSF) aircraft. Whilst DGTA can continue to rely on external specialist agencies additional work is required in progressing policy and guidance within the TAMM and the ADRM respectively. ACKNOWLEDGMENTS I would like to thank the following people for their assistance in reviewing and providing input to this paper: Mr Matthew Hansell (Ball Solutions Group), Squadron Leader Joseph Medved (DGTA-ASI), Squadron Leader Darren Hahn (DGTA- ASI), Flight Lieutenant Andrew Cruickshank (DGTA-ESI), and Officer Cadet George Parola (University of Newcastle). REFERENCES 1. Australian Defence Force, Airworthiness Design Requirements Manual, 28 September Australian Defence Force, Engine Life Management Manual, DGTA, October US Department of Defense, MIL-HDBK-1783B Engine Structural Integrity Program, 15 February US Department of Defense, Joint Services Specification Guide 2007, Engines Gas Turbine, 30 October US Federal Aviation Administration, Code of Federal Regulations Part 33, 1 January UK Ministry of Defence, Defence Standard General Specification for Aircraft Gas Turbine Engines, 29 May Bairsto, N.A., Fletcher, W.D.M., Engine Usage Condition Monitoring and Maintenance Management Systems in the UK Armed Forces, AGARD-CP-448 Engine Condition Monitoring, October Broede, J Design and Service Experience of Engine Life Usage Monitoring systems, 5 th European Propulsion Forum, Pisa, US Department of Defense, Joint Services Specification Guide 2007, Engines Gas Turbine, 30 October Aerospace Monitoring Systems Pty Ltd, AMS Flight Line System Users Manual 1590-HAWK-2100-MAN-Rev 3, 28 January Lockheed Martin Aeronautics Company, EMS Description for the C-130J Aircraft, J41C11A060, 20 February Merrington, G Proceedings of the ADF Engine Symposium, 19 August Hess, A The Prognostic Requirement for Advanced Sensors and Non-Traditional Detection Technologies, DARPA/DSO Prognosis Bidders Conference, Alexandria, Virginia, September Hess, A JSF Prognostic Health and Autonomic Logistic Concept, NATO RTO Conference Proceedings, Manchester,11 October HUMS 2003 Conference