The race is on innovations in aircraft structural inspection

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1 The race is on innovations in aircraft structural inspection Harnessing the power of Big Data and Internet of Things (IOT), aircraft manufacturers and airlines have embraced this super tool to carry out predictive maintenance that will decrease aircraft downtime and increase fleet reliability. And indeed, subject to the amount of investment that they are willing to make for Big Data analytics, if they really wanted to -airlines and OEMs have the ability to predict to a high probability when a component may fail in the future and prepare in advance whenever the failure happens or even better, before it happens. Big Data Not the panacea for everything However, there are still instances whereby these data analytical tools will never be able to predict - such as lightning strikes on aircraft and Ground Service Equipment (GSE) collisions. Big Data will never be able to predict when and where an aircraft will be hit by lightning; however the statistics of aircraft being struck by lightning is on average once a year. To compound the problem to the airlines, presently whenever a lightning strike or a GSE collision is reported on the aircraft, the ground time to recover the aircraft is usually long and unlike typical aircraft delays, getting the aircraft back into service is no longer measured in minutes, rather in hours or even days. As a result airlines suffer long downtime and loss of revenue, e.g. each Day Out of Service (DOS) for a Boeing 777ER is estimated to be USD$145,000. Recovery of the aircraft means carrying out all the tasks that are required in order for the aircraft to be safely release back into service. These include towing the aircraft to the suitable maintenance bays or hangar, carrying out the required inspections, identifying the damage areas and carrying repairs as given in the aircraft Structural Repair Manual (SRM). In worst case scenario, when the damage is beyond the scope of the SRM, the airline has to report back to the aircraft manufacturer on the damage, and wait (and liaise) for the required repair instructions before carrying out the repair work which can easily take days. Aircraft Structural Inspections One of the first and crucial task once lightning strike has been reported on an aircraft is to carry out the inspection of the aircraft to determine whether or not the aircraft has been damage and the extend of the damage. In addition to visual inspection, present day Non Destructive Inspection (NDI) techniques such as ultrasonic, eddy current, radiography, thermography, magnetic particle and dye penetrant inspections are carried out by trained personnel using specialised equipment. And because the equipment are usually handled manually, safe and good access to the aircraft exterior has to be provided to the personnel, hence towing of the aircraft to the hangar is generally preferred. Therefore the preparation work and the actual inspection take substantial time from anything between 4 hours on a narrow body aircraft to 6 hours or more on a wide body aircraft. Innovations in aircraft structural inspections let the race begin Many parties are aware the problem of extended ground time due to aircraft structural inspections from aircraft manufacturers, airlines, aircraft maintenance repair and overhaul (MRO) providers to even non-traditional MRO or aviation industry outsiders. Each has come out with their own ideas

2 on the solution to address this common problem how can we minimise the ground time required to carry out the aircraft structural inspections? New innovations in aircraft structural inspections methodologies such as 3D scanning using laser and using structured light, inspections by UAVs, and inspections by robots have been developed and being refined. Some have been brought to the market while others are still very much in R&D phase. The race is set on who can offer the best solution to the market! 1. 3D scanning using laser Among the different 3D scanning technologies, laser scanning is perhaps the most developed. Projecting laser light to scan objects, 3D laser scanning is broadly divided into 2 forms- laser triangulation scanner and time of flight laser scanner. Creaform had come out with its first portable laser scanner Handyscan 3D in The Handyscan 3D is a handheld and can be used to accurately map the surface of any free form object made from different materials. In order to detect any damages on the aircraft structure, first a reference structure or surface must be digitally created. There are a number of ways to do this, from obtaining the original CAD model to using software to form a theoretical initial geometry. Fig 1: Handyscan 3D (original model) by Creaform The Handyscan 3D together with photogrammetry was successfully used to identify the extensive damage that occurred on a Qantas Airline s A380 when one of the turbine disc in its engine No.2 broke. Besides the damage to the engine, the aircraft also suffered damage to the nacelle, wing, fuel system, landing gear, flight controls and even the controls for engine No. 1.

3 Fig 2: Damage to Qantas A380 VH-OQA 2. 3D scanning using structured light As opposed to using laser light, 3D scanning using structured light is the other main 3D scanning technology. Structured-light 3D scanner projects a series of linear patterns onto an object and by analysing the edges of each line of the pattern is able to calculate the distance and hence the shape of the subject. Instead of scanning one point or one beam at a time, multiple points or beams can be scan at once, hence structured light 3D scanners are usually much faster when compared to laser 3D scanners. fastcheck a 3D structured light scanner with augmented reality (AR) was developed by 8tree a relatively new start-up for aircraft fasteners (or rivets) inspection to improve quality in aircraft manufacturing. It has since been adopted by Airbus by for its assembly plant. 8tree followed up with another innovative solution for the Maintenance Repair and Overhaul (MRO) industry with dentcheck also utilises the same structured light scanning and AR technologies that is able to project the measurement results right unto the features that have been measured e.g. rivets, dents, etc. By projecting the color-coded results, the time consuming task of interpreting the data to the tolerance allowance given in the Structural Repair Manuals is reduced substantially. dentcheck has also been certified by Airbus. Fig 3: dentcheck by 8tree

4 3. Aircraft inspection using unmanned aerial vehicle (UAV) Since 2014, EasyJet together with its industrial partners has been developing UAVs to carry out aircraft structural inspections. Fitted with high intensity lighting and high definition camera for inspections, it also has a 3D laser scanner primarily for navigation and collision avoidance. In order to develop this solution, EasyJet has been partnering with different organisation with each providing their expertise for this project for example Bristol Robotics Laboratory, Coptercraft and Measurement Solutions earlier in the project, while latterly with Blue Bear Systems Research and Createc with their Remote Intelligent Survey Equipment for Radiation (RISER) solution. Fig 4: UAV from Bristol Robotics Laboratory, Coptercraft and Measurement Solutions Fig 5: UAV from Blue Bear Systems Research and Createc Presently due to regulations UAVs are only allowed indoors and therefore the aircraft still has to be towed into the hangars to carry out inspections by UAVs. However, EasyJet and its partners are working with the regulators and airport authorities to allow UAVs to be flown outdoors to carry out aircraft inspection.

5 4. Aircraft inspection using robots Using robots that are able to move along the aircraft external surface to carry out structural inspection is yet another method that is actively being researched. The robot can be fitted with different scanners and sensors that can feed data automatically to the central workstation where the data can be analysed real time. Lufthansa Technik has developed a robot named MORFI an acronym for Mobile Robot for Fuselage Inspection for metallic aircraft. Lufthansa Technik had collaborated with different organisations - Hamburg University of Technology, edevis GmbH and IFF GmbH, for this project. MORFI attaches itself and moves along the aircraft fuselage with vacuum pads as feet and is fitted a thermographic inspection unit that is programmed to examine aircraft fuselage for damage or cracks using standard NDI thermography methods. Lufthansa Technik is working to reduce its current weight of 75 kilos and to expand its usage to inspect composite fuselages. Fig 6: MORFI, an aircraft inspection robot being tested Meanwhile, Invert Robotics a company based in New Zealand had adapted a robotic inspection technology initially developed for inspecting industrial milk storage tanks to inspect aircraft fuselage. It had successfully carried out a demonstration with Air Zealand as recent as in May 2016 with its robot.

6 Local Hong Kong aviation industry So far, we have seen examples of aircraft structural inspections innovations being developed in other countries, what about the local Hong Kong aviation industry? Is there any research being conducted in the field of aircraft structural inspections? The short answer to the question posed above is yes. Besides the primary academic research being carried out by the local universities, Cathay Pacific Innovation Centre has been researching the use of the technologies mentioned earlier such as structure light (infra-red) 3D scanning and UAVs for aircraft damage inspections. HAECO, the largest Maintenance Repair Organisation (MRO) in Hong Kong and one of the world s leading MRO has been assisting the airline in their research. At the same time, HAECO has also been partnering with other organisations both local and overseas in the area of aircraft structural inspections by robotics technology and new aircraft structural repair methodology. Discussion regarding research in the local aviation industry would be incomplete without mentioning the Aviation Services Research Centre (ASRC) a research centre jointly established by The Hong Kong Polytechnic University and Boeing. With the expressed aim of bridging the gap between academic research and industry exploitation in the area of aviation services and MRO industry, ASRC together with industry members such as HAECO and HAESL has also researching new aircraft and engine inspection methodologies. Innovation and Technology in Hong Kong The Hong Kong SAR government has identified Innovation and Technology as one of the six industries to be actively promoted that will complement the 4 pillars industries. It has made it quite clear about this when the expressed theme of the latest government budget 2016/2017 is the promotion of innovation (and the exploration of new markets). Over HK$17 billion has been earmarked to boost the innovation and technology sector in the latest budget, and the term innovation has become a popular catchphrase almost to the point of being a clichéd. The Innovation and Technology Fund (ITF) which was established in 1999 has been instrumental in providing funding to many innovative projects over the years. Regardless whether ITF funding has been sought, it is encouraging to note that there are local organisations that are self-funded and have worked largely unseen to research innovative ideas and solutions that will truly address the needs of the industry and society.