Aircraft turbines produce high output by highly compressing air in the combustion chamber. Within the engine, the high-pressure turbine sits behind the combustion tube, subjecting it to great stress from exposure to the pressure generated by combustion energy and temperatures higher than 1,832°F (1,000°C).

Hollow cooling structures in high- pressure turbine blades and nozzle guide-vanes are manufactured using the lost wax process, with molten metal poured into a mold made by a wax model of the component. A heat-proof core in the model enables manufacturers to create parts that have hollow structures. However, a foreign object or processing defect in the hollow structure can reduce heat dissipation, potentially resulting in engine failure. Manufacturers inspect the inner part of the turbine blade’s hollow structure during manufacturing and engine maintenance to prevent such flaws.

Inspection challenges

Mini borescopes with a diameter of 3mm or less were used to inspect the hollow structures inside turbine blades for residues, scratches, and cracks. A rod lens in the mini borescope provided good-quality images but suffered from drawbacks that slowed inspection, including:

• Rigid, easily damaged, long, thin lens on insertion tube
• Small images difficult to see without a monitor
• A camera unbalances the scope, making it difficult to use
• Non-articulated insertion tube; can’t look around inside hollow structures
• Insufficient illumination from weak light guide

Thin videoscope advantages

Unlike a mini borescope, thin fiberscopes and videoscopes are flexible and offer articulation. A fiberscope is made of a bundle of glass fibers, while videoscopes have a built-in image sensor. Both have a 2.4mm OD insertion tube and articulation at the distal end.

Fiberscopes are cost-effective, although images acquired through the glass-fiber bundle have a mesh-like appearance that can make it difficult for users to detect tiny defects.

Videoscopes acquire images via a sensor providing bright, clear images with no mesh-like appearance. By electrically amplifying image signals, videoscopes enable users to observe deep inside a hollow structure with a wide field of view (FOV) and sufficient brightness, even with limited light intensity. This makes it easier for users to detect residues, scratches, and other defects.

Durability

The Olympus IPLEX TX videoscope’s insertion tube has a protective resin layer and 2.4mm OD. The insertion tube’s multilayered structure prevents resin surface damage from irregularly shaped parts, improving durability.

An ordinary videoscope needs to be entirely replaced when its insertion tube gets damaged, but a detachable insertion tube allows quick replacement on the IPLEX videoscope.

Summary

Inspecting hollow structures inside turbine blades presents significant challenges that can be overcome by using a videoscope with a small-diameter insertion tube. With durability, high image quality, and articulation, inspectors can easily maneuver inside these narrow structures, viewing, recording, and archiving images.

Olympus Industrial Solutions

Manufacturing carbon brake discs for aircraft requires specific skills, so raising production as orders rose forced Safran Group subsidiary Safran Landing Systems to upgrade its manufacturing methods with help from its machine programming consultant.

Original methods

More than 200 employees at Safran Landing Systems in Villeurbanne, France, play one of three complementary roles – weaving carbon fibers; performing heat treatment for conglomeration of fibers into strong, compact stock; and machining these fibers.

Increasing orders in the global aeronautics industry motivated Safran to improve its efficiency, responsiveness, and manufacturing methods to make a more reliable product.

Automating operations

MHAC Technologies, Safran’s partner in machine programming, spoke with Olivier Clausse and his team from Safran’s method office about implementing Esprit computer-aided manufacturing (CAM) software for CNC programming, optimization, and simulation. Safran chose Esprit’s SolidMillTurn Production Plus software, which handles C-axis index and rotary milling, Y-axis index milling, B-axis index milling, and 3rd rotary axis index milling. The system includes SolidMillTurn Traditional & Advanced and SolidTturn Multispindle, a 2-axis turning add-on.

Esprit software’s automatic macros define machining origins, offsets, and assemblies when programming Safran’s CNC lathes and 3- to 5-axis milling centers. Macros can automate and optimize operations based on the type of machining being done and stock measured directly on the machine. MHAC Technologies provided made-to-measure post processors for specific machines in Safran’s workshop.

Program reduction

Equipping the shop with updated turning and milling equipment became a top priority to boost brake production.

“One-and-done assembly is becoming a necessity in order to limit work-in-progress, guarantee better quality, and offer greater reactivity,” Clausse says.

Safran engineers chose to limit the number of programs used and standardized the rest to accelerate production. Program standardization arose, in part, from inspecting carbon discs on 3D measuring machines.

“We can define several families of disc brakes, which are only differentiated by a few dimension elements or machining operations,” Production Methods Engineer Mylène Loubatières says.

MHAC Technologies worked with Safran engineers to define brake families and create related programming macros, reducing the number of programs from more than 100 to several dozen.

“With Esprit and MHAC Technologies, we chose to combine ease-of-installation with service,” Clausse says.

One-and-done assembly is becoming a necessity in order to limit work-in-progress, guarantee better quality, and offer greater reactivity

Company growth

Embracing turning and milling while using Esprit CAM technology helped Safran remain competitive in the global aerospace market. In late 2018, Turkish Airlines announced that it had chosen wheels and carbon brakes from Safran Landing Systems for its fleets of 25 Airbus A350-900 and 25 Boeing 787-9 long-range aircraft. With artificial intelligence (AI) programming and collaboration between MHAC and Clausse’s team, Safran Landing System’s aircraft braking program is accelerating.

DP Technology

MHAC Technologies

Safran Landing Systems

The commercial drone delivery industry is quickly gaining popularity, attracting traditional delivery service providers and startup unmanned aerial system (UAS) manufacturers. The primary obstacle for these ventures is the strict body of regulations governing production and operation in the commercial market. Designing for these criteria early is much safer and more cost-effective than conforming to regulations later in deployment. Continued adoption of commercial drones depends on field programmable gate arrays (FPGAs) that enable them to meet these regulatory requirements while also solving size, power, and reliability challenges; eliminating the risk of high-altitude radiation-related failures; and protecting against a growing range of cyber threats.

The main factors affecting drone avionics often require tradeoffs between security, processing performance, power, mass, and form factor. These can all be addressed with the latest generation of FPGAs.

FPGA solutions

Drone designers need small, power-efficient, reliable electronic components that are secure against malicious threats. Stringent power, size, and weight constraints impact battery life. In addition to these requirements, UAS are subject to harsh environments such as neutron effects, moisture, and extreme temperatures.

Like all avionics systems, those in UAS need to be as compact and as light as possible, minimizing or eliminating heatsinks. Smaller electronic components reduce the printed circuit board (PCB) and electronics enclosure size, reducing total system weight while improving efficiency, battery life, and flight time.

Flash-based and silicon-oxide – nitride-oxide-silicon (SONOS)-based FPGAs address these challenges for all drone system applications including sensor interfacing, flight control, and image processing. These types of FPGAs consume the least power – up to 50% less power than their static random-access memory (SRAM)-based counterparts (Figure 1). They remove the need for heat sinks and reduce the weight of the overall system without sacrificing total system efficiency.

Because commercial UAS avionics must meet DO-254 standards, drone manufacturers must select components with an extensive service history, necessary for certification. For aviation manufacturers, this means selecting vendors that can provide the necessary documentation and guidance for DO-254 certification.

Selecting components that are immune to configuration neutron single event upsets (SEU) is another important consideration (Figure 2). Neutron flux (neutrons per cm2 per second) increases with altitude. For example, rising 40,000ft above sea level (a typical commercial aviation flying altitude) increases neutron flux by a factor of 515. Neutron SEU could result in a device malfunction and failure, resulting in a catastrophic event if a drone breaks down and lands on a moving vehicle at high speed, or if it’s transporting vital supplies to a patient.

For drones flying in U.S. states such as Colorado, Utah, and New Mexico with a ground-level elevation close to 10,000ft, neutron effects begin to be noticeable, increasing the neutron flux 12x. Flash- and SONOS-based FPGAs are immune to radiation-induced configuration upsets and won’t lose functionality at these altitudes.

Security is another concern in aviation applications. Security starts during silicon manufacturing and continues through system deployment and operations. Flash- and SONOS-based FPGAs represent the industry’s most advanced and secure programmable FPGAs. In addition to embedded security crypto-processors, these FPGAS include key capabilities required to create a trusted and secure hardware platform for a secure embedded system, making them invulnerable to cloning, copying, and reverse engineering. Sensitive data in embedded systems is protected from malicious attacks. Some of these key capabilities not offered in SRAM-based FPGAs are secure key storage using physically unclonable function (PUF) and licensed, patent-protected differential power analysis (DPA) pass-through. Any programmable device is vulnerable to attacks, so designers need to buy electronics with security features produced by trusted manufacturers.

Conclusion

Drone delivery today is heavily restricted by transportation authorities, primarily due to concerns for human safety and privacy. By designing drones to mitigate these concerns, manufacturers can directly influence the industry’s acceleration. Flash- and SONOS-based FPGAs enable developers to account for safety, security, and reliability throughout the design and deployment processes, while also reducing the size and cost of drones and mitigating the risk that radiation-related configuration upsets will cause them to fail at higher altitudes. These FPGA characteristics solve some of the biggest challenges that drone and electronics designers face and can be the answer to making commercial drone delivery a regular occurrence in the very near future.

Microchip Technology Inc.

About the authors: Maria Zaitchenko is a student at the University of Toronto, in the faculty of Applied Science and Engineering. She can be reached at m.zaitchenko@mail.utoronto.ca . Julian Di Matteo is senior product marketing engineer, space and aviation, Microchip. He can be reached at julian.dimatteo@microchip.com.

With uncertainty surrounding aircraft manufacturing, maintenance, and repairs (MRO), sticking to a timeline while maintaining efficiency is difficult. Most aircraft require some level of daily maintenance, but with many variables in play, no aircraft perfectly fits a maintenance schedule. Despite plenty of data being collected, it is rarely leveraged properly to reduce unknowns, making day-to-day maintenance and depot work complicated. Solutions that address uncertainty provide more comprehensive insight into operations to optimize production and repair schedules.

Problems

Manufacturing challenges are different than MRO challenges. Maintenance needs of one plane can differ drastically from another identical model. No two planes are exposed to the same conditions or usage and therefore do not need the same support on the same schedule.

An aircraft’s location, for example, directly influences the time between maintenance. Other factors – such as incomplete maintenance logs, unexpected issues, fleet usage, age, and weather – also make it difficult to create accurate maintenance schedules. In many cases, unexpected issues are only evident after starting repairs, causing major delays or strain on expensive personnel.

For depots, aircraft may be scheduled for repairs with a three-week turnaround, but it can take more than a year to procure some parts. And if a specialist is not available, repairs will be delayed. With differing levels of experience needed for each airplane and task, not having the right staff will cause major downtime. These challenges create real need to accurately predict companies’ MRO needs and when those needs will occur.

Current solutions

Existing systems attempt to solve these problems, but they don’t quite succeed. Front-line maintenance solutions track each airplane’s usage by tail number. Based on recent usage data, systems automatically project future usage and estimate when maintenance should happen. In practice, the systems inaccurately extrapolate into the future. Variables such as uneven usage can wreak havoc on these predictions. For example, if a plane is parked for a few days, the system may predict no needed major overhaul for years, but for a plane making cross-country trips in that same timespan, the system may predict major maintenance requirements in a month. This clearly does not properly account for variation in aircraft usage.

These solutions also fall short when it comes to staffing forecasts. Without strong analytics, the only way to lower risk is to hire more people than necessary.

Predictive, prescriptive analytics

Predicting likely outcomes and prescribing responses are central to a strong analytics solution, reducing downtime and inefficiency. Solutions such as TruProcess from Lone Star Analysis provide a more accurate outlook. TruProcess provides a unified view of assets using new or existing data collection systems. Data analysis then generates insightful and transparent predictions and prescriptions.

Lone Star Analysis shows spans of uncertainty more accurately account for unknowns than projected trendlines. Instead of looking at every asset and predicting one future, the system considers the fleet as a whole and considers multiple futures, giving a probability to each. This is followed by recommendations and percentages of certainty. This big picture outlook enables more accurate decisions by eliminating assumptions. By considering uncertainty, parts can be ordered in advance, staffing becomes easier and more efficient, and repairs are quicker.

Companies also need to better understand weather’s effects on MRO. Planes located primarily in a desert need maintenance more often than those located in cooler locations. Most depots already use analytics to harness historical weather data to better predict when something such as thermal paste needs to be reapplied. That thinking should be applied to major overhauls as well.

Lone Star Analysis

Depot maintenance

Having the right technicians and mechanics can go a long way toward increasing efficiency. A delay in refurbishment or overhaul stemming from staffing issues creates a ripple effect. The opposite is also true – if a job is done early but the correct technician isn’t scheduled to work yet, there is no benefit from finishing the previous job quickly. On top of providing inventory, maintenance, and staffing guidance, solutions can find and address efficiency bottlenecks. Systems can recommend machinery and expansion investments by building a simulation (digital twin) that analyzes the best future options for productivity and cost.

Benefits of analytics

Each aerospace organization has its own problems, but there are solutions that can make airplane manufacturing and MRO faster and more efficient; make staffing and inventory management easier; increase production with less downtime; and understand when expansion may or may not be needed. Predictive and prescriptive analytics solutions can be tailored to address each issue while leveraging existing data and technology to make it happen.

Lone Star Analysis