Military, Services

Mining for the Next Aviation Diamonds

By By Mike Hangge | November 5, 2014
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An Airbus Helicopter EC155 B1 in Marshall, Minn. Photo courtesy Metro Aviation

Just like the helicopters that Health and Usage Monitoring Systems (HUMS) and Helicopter Flight Data Monitoring (HFDM) systems are installed in, there is no single solution for every user’s needs. Each system has its own unique capabilities just as each manufacturer has its own approach. But to be a viable solution in the future, users and manufacturers both agree that these systems must operate, measure, detect, connect, report, and adapt reliably, efficiently, effectively, and accurately at all times. If the systems cannot do these tasks to an ever-increasing standard, then the entire concept may quickly go the way of Betamax video cassettes.

Geltz stated that “the ability of North FDS’ system to not only track the aircraft but stream live data from the helicopter, monitoring the systems and flight operation, with alerts and real-time data analysis, far exceeds the FAA intent.” Photo courtesy Metro Aviation

Since the notion of helicopter vibration monitoring emerged in the mid-1980s, HUMS and HFDM systems have been continuously developing as a technology that will save time, money, and, most importantly, lives. The technological lifespan of these systems has begun passing the research & development stage and, according to Jeff Warner, president and CEO of North Flight Data Systems (NFDS), “are currently in the growth stages. New innovative and affordable recorders and vibration acquisition platforms can now be seen on the horizon.” They are on the uphill slope of their technological S-curve and have recently experienced a dramatically vertical growth stage, but they aren’t yet at the pinnacle.

According to George Grove, vice president of Helitune, “these systems have been evolving for the past 20-plus years and continue to improve using the latest advancements in technology every day. Suppliers are currently working at reducing size, weight, cost, and overhead all while improving how, what, and when to acquire data.”

UTC Aerospace Systems’ HUMS product line provides proven functionality with minimal weight. Photo Courtesy UTC

Kristen Law, director of maintenance strategy and condition-based maintenance for Honeywell Aerospace, also mentioned that, “while many HUMS suppliers are already providing third or fourth generation systems, HFDM is a slightly less mature and broader range of products that range from cameras to links between avionics data and flight data recorders.” Both of these systems, however, are truly benefitting from their day – 20 years prior and the technology to implement them would have been too immature, 20 years later and the concepts would have been outdated.

As good as these systems are now, their futures will be even more impressive. The advancements that will be realized within the next few years may astonish even those within the industry. Manufacturers are currently working on projects that seemed unachievable only a few years prior. But this rapid progression demands user buy-in today. If users have specific wants or desires, now is the time to address those requests. Manufacturers are eagerly working at fixing the issues that they can foresee, but without specific user input, they are left to solve only the problems within their own purview.


Better a Diamond With a Flaw Than a Pebble Without

Helitune and ZF Luftfahrttechnik are working to derive a production variant for their Smart Pitch Rods. Photo courtesy ZF Luftfahrttechnik

Confucius might have argued that a good system installed is better than a perfect system on the shelf and it would be difficult to argue with his logic. The struggle between perfection and simply good enough has always existed, but the exponential expansions in technology today make that struggle even more fluid.

The build sheet for that ‘perfect’ system is difficult to describe. Future generations of these systems will likely include all of the features and functionalities current operators have come to depend upon, but will also see improvements in processing power, wireless sensors, flexibility, integration, connectivity, on-board diagnostics, and real-time data alerts. Law commented that “future systems may integrate maintenance computing and maintainer decision support similar to what commercial fixed wing aircraft have been offering for many years. Integrating maintenance decision support tools with the aircraft systems will allow faster aircraft turn time similar to commercial airlines’ ability for fast turn times at the gates, which is critical for helicopter operators who rely on having high aircraft availability.”

Though every user has different needs and desires which fit their unique platforms and price points, there are many features common to nearly every wish list.

Ease of Use

Honeywell’s Sky Connect Tracker III.
Photo courtesy Honeywell

In an age of technology where a smart phone can control the operations of an entire building, it isn’t impossible to envision a means of easily accessing and understanding the complex information that these systems provide. On-board diagnostics (OBD) systems have been installed in automobiles since the late-1960s and are now standard on nearly every vehicle produced today. While even the current OBD-II would not be capable of passing the vast amounts of information that a HUMS/HFDM is capable of attaining, adapting that same mindset to our aviation diagnostics tools to standardize the information and collection methods may improve the desirability and usability of these systems.



Geltz stated that “there has been a lot of discussion on what equipment will meet the FAA’s Helicopter Emergency Medical Services (HEMS) rule which was intended to foster quality assurance monitoring in HEMS operations.” Photo courtesy Metro Aviation

In every aspect of life today, connectivity seems to be the most demanded and fastest developing technology. As newer and more capable means of connecting become available, the demand to collect and transmit more information also increases. As the technology advances and data rates increase, more HUMS analysis and HFDM information will be transmitted real-time over satellites. A product like Honeywell’s SkyConnect Tracker III is just one example of advanced connectivity to improve real-time vehicle health status and maintenance alerts. Smaller companies like North FDS are joining with Metro Aviation, OuterLink, and Viasat to better balance and expand their product capabilities. By working together, they are enhancing the functionality of NFDS’ existing HFDM recorder and bolstering it with new broadband satellite connectivity to bring the proven U.S. military Blue Force Tracker II technology to the commercial market. PHI, already known as a leading user of HUMS and HFDM technologies, recently announced that they will be the launch customer for this new technology which will also include a global push-to-talk satellite radio feature.

As connectivity technology reaches its own levels of maturity, a totally connected helicopter will become commonplace and enable operations and maintenance teams on the ground to receive real-time performance data and alerts to quickly analyze and identify trends on emerging faults. It is even conceivable that helicopters will eventually download data wirelessly and have the ability to self-diagnose and contact their operators when specified parameters are outside limits.

In-Flight Connections

Helitune and ZF Luftfahrttechnik have already flight tested their In-Flight Tuning system using Smart Pitch Rods to dynamically optimize vibration levels through all usage regimes. Photo courtesy ZF Luftfahrttechnik

Vibrations are arguably the most destructive force to long-term helicopter operations, yet they are currently minimized only at scheduled intervals. By automatically monitoring and minimizing those vibrations, the strain on the airframe, parts, and occupants is dramatically reduced while also minimizing parts replacement and lengthening the lifespan of the airframe. Helitune and ZF Luftfahrttechnik recognized this issue and have already conducted successful flight testing towards a production variant of an in-flight tuning system for helicopter rotors that continuously collects vibration levels and uses Smart Pitch Rods to dynamically adjust the blade pitch and optimize the vibration level through all usage regimes.

Big Data

One of the most difficult issues to solve with these systems is how to manage and display the massive amounts of information. Ken Speaks, CEO of RMCI, stated that the “ground station software and support is the greatest shortcoming of current-generation HUMS. It is not easy to manage, display, and process this data in an optimal manner. As a result, legacy ground stations do not allow HUMS users to get the greatest possible benefit from their systems.” Therefore, there must be a logical balance between needs and capabilities, data collection and processing abilities. Chris Carella, manager of HUMS strategic planning at UTC Aerospace Systems (UTAS), adds that “the industry is still learning how to leverage the large amounts of data collected by HUMS. Using ‘big data’ technologies for off-board analysis and fusing data from other aircraft systems is expected to lead to even more improvements in operations and maintenance.”


Helitune’s Rotortuner Vehicle Health Monitoring System displays rotor smoothing information in an impressive and logical manner. Photo courtesy Helitune

No technology, regardless of its benefits, will flourish if its costs significantly outweighs its benefits. The cost effectiveness of these systems can sometimes be lost in the sales pitch though, as HUMS only saves money if it’s properly utilized and HFDM only provides a return on investment if the business culture allows its full usage. Fortunately, this cost-versus-benefits issue will improve dramatically as the technology becomes more common and the systems more prevalent. The technology, equipment, and installation are obvious expenses that will quickly begin to diminish, but expenses such as labor, upkeep, and data extrapolation are often underestimated and are, in the long-term, a more critical expense to be considered. If operators are more aware and accepting of the total costs of these systems, it will be easier to recognize the values they provide.

Reduced Weight

According to Warner, “there is a new surge of avionics manufacturers who have developed flexible, lightweight recording systems and have done the system integration and certification on their own.” Many of the systems used in helicopters today are based on designs that were released in the twentieth century. They are heavier and use more power than the next-generation systems that are now becoming available. MEMS gyros, digital data bus architecture, and smaller, lighter, more efficient computing platforms are providing significant increases in the amount of data captured at lower costs in both weight and money. Technology, such as wireless sensors, will enable faster installation times and may reduce the overall system weight by up to two-thirds. Companies like UTAS are working on programs such as their Remote Sensor Interface Module which reduces wire weight by processing sensor data near the source.


No purchasing agent wants to buy into a product at the end of its growth span. The ultimate desire is to purchase an effective system that will continue to grow as more technologies become available. While upgradability has always been one of the greatest hurdles for a manufacturer, the majority of these companies are working diligently to provide smarter designs and installations which will allow the flexible architectures required to speed that growth. One example of this is the ability to add additional remote data concentrators which can reduce overall wiring weight and cost while enabling easier upgrades for newer sensing capabilities.


“Though we continue to refine signal processing and algorithms, the core of HUMS, mechanical diagnostics, is relatively mature.” Carella continued to say that the industry is now embarking on the next phase of HUMS—prognostics. With prognostics, maintenance and operations can be further optimized by providing information on remaining useful life. Prognostics has the capacity to give end users improvements in supply chain efficiencies, reduced inventory, and lower storage and handling costs. The world of vehicle health is moving beyond mechanical diagnostics and monitoring to include emerging sensing capabilities such as structural health as well as using data for prognostic evaluations. The capabilities for automating data management and prognostics are the new pieces that both the industry and end users are looking for in the future.

Greater Manufacturer and OEM Collaboration

Until recently, HUMS/HFDM have been considered an afterthought in the manufacturing of helicopters. Many OEMs have begun offering aftermarket data service programs and, with recent advancements and designs, several OEMs have now begun implementing these systems into the helicopters during the build process. This provides a less expensive and more thorough solution which may offer more proactive and predictive algorithms/thresholds while also eliminating many maintenance checks which would have otherwise been deemed necessary.

HUMS and HFDM Integration

To many, these two systems complement each other like eggs and bacon. Law even stated that by combining the health status and trending data from HUMS with the flight operational data from HFDM, operators will be able to more accurately determine the root cause for maintenance actions. Understanding how the helicopter was operated at a given point in time, and comparing that with health status signals from the HUMS system at that same point is useful for pilot training and better understanding of equipment wear in relation to flight regimes. Taking this a step further, the correlation of flight operation and HUMS trend data can be used to more accurately predict when maintenance events will be required and may lead to maintenance time extensions. The first stage of this is the development of ground-based tools that can view both HUMS and HFDM data to aid in the correlation of flight events with HUMS events.

Earlier HFDM Integration

Though not exactly a future technology improvement, HFDM information needs to be incorporated earlier as a means to prevent accidents rather than to simply provide flight information after the event. As this technology gains traction and its value is better realized, it will become as familiar as automotive airbags and just as important to the safety of the occupants.

The Brilliance of the Final Cuts

Across the span of the last six months and three different articles, Rotor & Wing has sought to demonstrate the value of HUMS and HFDM systems. Manufacturers are currently working on the final cuts towards perfection and the future promises that the brilliance of these cuts will make them shine like the aviation diamonds that they are.

Though the capstone of these articles covers the future possibilities, this should not sway potential investors from purchasing and installing the current systems. There is so much value that these systems already provide and the culture which they foster will improve many aspects of nearly any company. It’s an exciting time for these systems as they near maturity and, for some companies, waiting for that next level of progression may be the best answer, But to paraphrase General George S. Patton, “a good system installed now is better than a perfect system installed next week.” 

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