Technologies with Safety Benefits

Michel MASSON • 3 June 2020
in community Rotorcraft

Helicopter manufacturers constantly introduce new technologies into their products, and the regulatory system is getting better at keeping up with this progress. 

If you are in a management position at an operator, do you actively think about what technologies are right for your operation? And for flight crew: how does technology impact the way you manage the flight? 

Assess how technology can help to improve safety and operational effectiveness

Many accidents with injuries or loss of life could have been prevented by technology. Technology offers a variety of safety and operational solutions that can, directly or indirectly, address important safety issues and contribute to accident prevention.  It can provide tools to increase and simplify the information available to the flight crew, reduce pilot workload, support decision making or increase survivability.

The Specialist Team Technology of the European Safety Promotion Network Rotorcraft (ESPN-R), formerly known as the European Helicopter Safety Team (EHEST), started working on coordinating efforts to promote the use of technology in 2010 when they derived the highest ranking accident factors from analysis of 300 helicopter accidents and incidents that took place in Europe between 2000 and 2010.

EHEST Top 15 "most promising" technologies

This Team assessed the safety potential of numerous technologies and their report identified the 15 ‘highly promising’ technologies that can jointly help to mitigate 11 of the top 20 accident factors.  These key technologies are:

  1. Enhanced Ground Proximity Warning System / Terrain Awareness and Warning System.
  2. Digital range image algorithms for flight guidance aids for helicopter low-level flight.
  3. Laser radar obstacle and terrain avoidance system.
  4. Digital mapping.
  5. Deployable Voice and Flight Data Recorder.
  6. Passive tower-based Obstacle Collision Avoidance System.
  7. Miniature Voice and Flight Data Recorder.
  8. Wire Strike Protection System.
  9. Flight data evaluation and processing for accident and incident investigation.
  10. Cockpit Information Recorder.
  11. Full Authority Digital Engine Control (FADEC).
  12. Light Helicopter Operations Monitoring Programme (HOMP) systems.
  13. Efficient Numerical Approaches for On-Board Rotorcraft Flight Performance Modelling.
  14. Radar Altimeter for altitude measurement.
  15. Immersive Visualisation.

It’s worth reading the full report that you can find here.  The report also made recommendations to industry, regulatory authorities, researchers and universities to act upon the conclusions.  The work resumed in 2017 as part of the European Plan for Aviation Safety (EPAS) Safety Promotion Task SPT.095 to “Promote technologies with safety benefits”. For each of the previously mentioned ‘highly promising’ technologies, the current status has now been reassessed. Unsurprisingly, many of these have evolved into fully-fledged solutions that are available on helicopters today while others are likely to be available in the near future. 

More recently, in December 2019 the ESPN-R hosted a workshop on the Safety Benefits of Technology as part of the EASA Rotorcraft Symposium 2019.  Experts from the manufacturers and the authorities provided some interesting presentations to the workshop – it is worth looking at the presentations that can be found on the event webpage here.

The situation today – What technologies are already available?

Depending on the type/ age of helicopter and the type of operation you fly, the installation of some technologies are likely to be mandatory.  However, there are other technologies that you may not be required to have but that could still bring you safety and operational benefits.  The main technologies available on the market today are summarised below, along with some of the benefits and safety improvements they bring – some of these are obvious, but others you might not be aware of.  You can read more in the status update report NLR-TP-2018-470 here.

The main technologies are split into 3 main categories.  The first is to improve situational awareness and is specifically helpful in preventing obstacle and terrain collisions.  The second is associated with other areas of flying, specifically flight/engine control.  Finally, the last area is associated with flight data monitoring, post event analysis and recorders to assist in finding people after an accident or helping with the analysis to prevent future accidents. 

1.  Situational awareness and the prevention of Obstacle/ Terrain Collisions

Digital mapping and flight applications

Digital maps are now available in many forms, ranging from professional types presented on glass cockpit Multi-Function Display (MFD) screens, down to tablets and other devices.  When coupled to a satellite positioning system receiver, the maps can show the actual (2D or even 3D) helicopter position.   Many databases are available, including obstacle and terrain databases. Because of the low threshold entry level of tablet-based systems, digital (moving) maps are becoming a key situational awareness tool for pilots in all parts of the Rotorcraft community.  However, it is important to continue looking out of the cockpit window as well, as demonstrated in the Together4Safety video on reducing terrain collision risks. 

Digital range image algorithms for flight guidance aids

When planning helicopter low-level flight or terrain-following flights the dynamics are difficult to model.  Because detailed calculations are computationally expensive, the state space is only represented in an approximate manner.  A new planning algorithm has been developed for the vertical component of terrain following flight paths using methods of energy, where the path itself is modelled as an elastic band deformed by virtual forces to follow the terrain.  Another terrain-following approach, aimed at drone applications, makes use of a monocular vision-based height estimation algorithm for terrain following flights. It consists of using optical flow to track features from videos obtained by the air vehicle, as well as its motion information, to estimate the flying height. The approach to estimate the height was inspired by the classical stereo vision technique, but uses images from a single camera acquired at different times.

Helicopter Terrain Awareness and Warning Systems (HTAWS)

HTAWS is a development of traditional Ground Proximity Warning Systems (GPWS) specifically aimed towards Rotorcraft.  It addresses some of the shortcomings of GPWS such as only being able to detect terrain directly below the aircraft and not detecting the aircraft closure rate to the ground. HTAWS combines a worldwide digital terrain database with an accurate navigation system.  It is available from several manufacturers and while it is a requirement for large helicopters (maximum weight over 3,175 kg) with a passenger seating capacity of more than 9 and flying IFR, it is not mandated in all cases.  HTAWS bring some excellent safety and operational benefits as additional equipment. 

Laser radar obstacle and terrain avoidance system

In addition to terrain, there are also challenge in detecting other primary obstacles such wind power turbines, trees, high voltage transmission lines and other wires that cannot be easily seen by the pilot. For large rotorcraft the HELicopter LASer (HELLAS) radar system is available and is particular useful if a lot of operator activities takes place in a low level environment.  The system has been flight-tested on smaller helicopters and provides a light-weight solution, although in some cases the detection range is limited. The next step for this technology is to enable automobile collision avoidance systems that also are used in driver-less cars.

Passive Tower-Based Obstacle Collision Avoidance System (OCAS)

OCAS consists of units, located on utility and power line towers, that detect air traffic entering a predefined warning zone.  The system then activates warning lights to illuminate the obstacle. It aims to alert aircraft to the structures to which it is attached, while minimising the visual impact on the surrounding environment.

Wire Strike Protection System (WSPS)

WSPS is a passive, low cost, low weight and maintenance free system. Wire cutters are available as an option for more than 70 models of military and commercial helicopters of all major helicopter manufacturers around the world, nowadays even down to single engine helicopters in the size of the Robinson R66 Turbine.

2.  Flight/Engine Control

Vortex ring state risk reduction

Vortex Ring State is a common feature in aircraft accidents.  Airbus Helicopters have conducted system research trials for a cockpit warning of vortex ring state.  The system provides the flight crew with a warning of vortex ring state to help them trigger evasive action.  Warnings are normally at 2 levels, the first to identify an impending ring vortex state and the other to provide awareness of a possible ring vortex condition.  The ultimate goal is to assure a warning time of 5 seconds prior to entering vortex ring state. 

Full Authority Digital Engine Control (FADEC)

The use of FADEC in fixed wing aircraft as well as larger rotorcraft is widespread for many years now.  FADEC not only provides for efficient engine operation, it also allows the manufacturer to program engine limitations and to receive engine health and maintenance reports. On piston engines the FADEC system effectively replaces magnetos, carburettors, mixture control and prop control.  Because it maintains the fuel/air ratio on each individual cylinder within narrow tolerances, it bypasses the most common cause of engine failure: mismanagement of the mixture control.

3.  Flight Data Monitoring and Recorders

Miniature Cockpit Voice and Flight Data Recorder (CVFDR)

The Miniature CVFDR is intended to be smaller and cheaper than the conventional recorders.  It can have all relevant sensors (pressure, gyros, GPS) integrated in case the helicopter itself does not provide the necessary data. They are fully integrated flight data recorders that provide a combination of cockpit voice and flight data recording, an airborne image recorder and a data link recorder. This is a system with low weight and size, but initially aimed at flight test installations.

Cockpit Information Recorder System (CIRS)

Another solution for flight recorders for GA applications is provided by the CIRS, specifically aimed at smaller helicopters. The Vision 1000 system is a self-contained, light-weight and low-cost flight data recording solution, specifically aimed at light helicopters. The system only requires aircraft power and ground, and records attitude data, position and speed data, cockpit images and sounds (ambient and intercom). It is Airbus Helicopters strategy to fit each delivered helicopter with the Vision 1000 system and provide affordable retrofit solutions for the in-service fleet, especially the light range.

Deployable Cockpit Voice and Flight Data Recorder (CVFDR)

The deployable CVFDR is a new development that deploys (‘ejects’) the crash-survivable memory unit in case of an accident.  Such a system was first announced in mid-2017 and it will be lighter, more compact, and provide new capabilities compared to current generation of recorders. Designed to float, the crash-protected memory module containing recorded cockpit voice and flight data will be equipped with an integrated Emergency Locator Transmitter (ELT) to help rescue teams to rapidly locate and recover flight recorders.  This type of equipment is vital in saving lives after an accident. 

Flight data evaluation and processing for accident/ incident investigation

The system comprises devices for voice, mission and flight data recording, but also for the transfer of data for post-mission analysis and includes Flight Data Monitoring (FDM). This web-based application allows accessing past and current flight data, generating detailed reports, and trending the safety improvements in the operations, by providing automated flight data and events analysis.

Light Helicopter Operations Monitoring Programme (HOMP)

HOMP is a preventive flight data monitoring system with the aim of improving flight safety, based on the automatic detection of previously-defined events. It is an industry standard in the offshore community and large helicopters.  As we discussed in our recent article on FDM for small rotorcraft, the technology is continually improving and the systems offer huge benefits for the whole community. 

Safety benefits

EASA and the working groups establishing the Rotorcraft Safety Roadmap in 2018 have evaluated these technologies and all of these have been recognised as having safety benefits. Moreover, most of them were indeed selected as “Net Safety Benefit” elements within one of the Roadmap’s workstreams. Another key driver safety enhancer as a result of the experts’ discussion not mentioned so far but entered in this workstream is:

Enhanced availability of autopilot solutions for small rotorcraft. This is seen as important and as being a key contribution for better inflight stability and pilot workload reduction.

Future technologies

In parallel, several new or emerging technologies to enhance helicopter flight safety have been identified, and a number of new or modified regulations have been put in place in recent years to enforce or facilitate the use of certain technologies:

  • Collective Pull Down (CPD)
  • Emergency breathing devices
  • Helicopter Emergency Release Operator (HERO)
  • Emergency exit training device
  • High-speed data via satellite communication
  • Eye for Autonomous Guidance and Landing Extension (EAGLE)

Maximising the benefits of technology through training and Standard Operating Procedures

Using technologies safely, effectively and to the best of their potential requires appropriate training and procedures. Never stop training and use procedures as reference for action. If you have questions, do not hesitate to ask. If you encounter issues with the technologies, training contents or procedures, don’t hesitate to provide feedback and suggest improvements.

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