Emerald Group Publishing Limited
Copyright © 2004, Emerald Group Publishing Limited
Technology – help or hindrance
Technology – help or hindrance
Keywords: Aerospace industry, Conference, Civil, Military
A variety of topics were discussed at this conference at the Royal Aeronautical Society in both the civil and military rotorcraft areas of operation. A civil perspective was explored by Nigel Talbot, Deputy Chief Test Pilot of the UK CAA in which he referred to the harsh environment of offshore operations in the North Sea using rigs and vessels of various types, and the multitude of onshore operations including Police and EMS, Pipe Power Line Inspection, Filming, Training and Private Flying/GA. The problems encountered in all of these areas can include cost, noise, safety standards, icing, poor weather, and the maintenance of stability/control margins.
For 2003 UK registered helicopters above 2,730 kg, mishandling was the greatest cause of accidents, followed some way behind by mechanical failure, wire strike, disorientation and other causes. The title of this conference can be applied particularly to the use of GPS; if friend is mentioned, it can include the avoidance of controlled airspace, give a highly accurate navaid, improve lookout and approaches and allow operations in poor weather. On the other hand as a foe, it can induce pilots to fly in poor conditions, have undue influence on pilot behaviour and can be used for inappropriate purposes. Other influential technologies include TCAS, EGPWS, Capstone and NVG. One has to consider all the aspects of airworthiness, operational rules and training.
Particular mention is made of Full Authority Digital Engine Control (FADEC). In this context friendly features include a major enhancement in engine management, reduction in pilot workload and the enhancement of performance for the same power. However, not so friendly aspects include a single channel FADEC for a single engine helicopter, the assumption made that transfer from auto to manual control in event of FADEC failure is seamless, difficult failure drill, and overall, a step backwards.
Technological opportunities include fly-by-wire (FBW) which needs development including sidestick controller, and tiltrotor handling qualities. Some successes include Health and Usage Monitoring (HUMS) making use of the QAR recording flight data events and measurements and subsequent analyses.
A military perspective
This aspect was explored by Cdr. Steven Davies RN, CO Rotary Wing Test Squadron, Boscombe Down. He began by using the example of military night enhancement vision systems which experience since 1978 began with the conventional night stream and has progressed by way of beta lights on upper blade tips, flight testing early NVG (night vision goggles) with further operational use having a better cockpit integration. Flying training issues were also addressed, leading to flight testing of further improvements in 2003.
Before technological developments, operating at night posed many difficulties and the introduction of beta lights on upper blade tips made close formation flying at night with minimal references possible. It required lots of practice however and required above average piloting skills and very quickly fell out of favour. The technology leap came with the advent of night vision goggles (NVG) and early uses such as in the Falklands, recognised that formal NMVG training was required as well as greater levels of currency. In the late 1980s improved NVGs became available and better cockpit integration. This included instruments backlit with NVG-compatible lighting and in addition, NVG skills were taught on training squadrons prior to joining front-line units.
There is no doubt that evolving technology has increased operational capability although this is a very demanding skill to acquire and a greater amount of continuation training is required. There are many layers of additional cost, including prevision of technology, integration into the cockpit, additional training, and recruiting/ screening for higher calibre students initially. Other considerations include the possibility of overconfidence when technology is involved.
Recent flight trials have included those with the Rotary Wing Test Squadron at QinetiQ Boscombe Down with the Chinook Night Enhancement Package which has a thermal imaging turret and a Display Night Vision Goggle (DNVG) system. The Puma Mk 1 has also been used with display NVG with CRT projection of symbology into one monocular to overlay the symbology set on the NVGT image. Work is under way on R&D projects with Bedford and Farnborough to evaluate newer/ novel technology including Panoramic NVG.
Vision systems – NVGs and beyond
This was addressed by Adrian Ball, technology chief, QinetiQ, UK, who dealt with the vision system requirements for existing equipment as well as those beyond NVG. Helicopter pilotage tasks include: flight control – velocity, acceleration, attitude; guidance – terrain, obstacles, closure rate, time to impact; navigation – map reading, position within co-ordinate system; mission tasks – radio communications, cockpit systems. In addition, information has to be extracted from the visual scene. The latter can be by cueing mechanisms such as optical flow, motion parallax, perspective, feature recognition and scaling, and texture.
NVG developments include improved high and low light capability, filmless technology, gated technology, increased gain, information displays and developments in field of view. Beyond NVGs can be a range of vision system technologies forming an integrated mission system and leading to Intelligent Flight Path Guidance (IFPG) which enables safe, tactical, contact flight in any visual environment.
The requirements for various environmental conditions are illustrated. Enhanced composite pilotage displays can include image fusion which has been demonstrated in 2003 with passive millimetre wave. Active and passive sensors are available. For visually coupled systems, a head tracking system can be linked to a graphics symbol processor and image processor, combined with sensor steering and a precision navigation system. Integrated helmet display systems have made significant advances and the technology continues to move ahead.
Flight demonstrations have been undertaken of vision systems with manoeuvres in a Lynx helicopter. Those employing enhanced synthetic vision and head-tracked display are among features that lead to conclusions that no single technology will provide the vision system capability required in the future. A suite of sensors operating in different wavebands is required and integrated sensor/ processing/display/human-centred systems approach is essential.
Human factors overview
Given by Col. Malcolm Braithwaite, consultant adviser in Aviation Medicine (Army), he spoke of the hazards to flight safety and mission effectiveness where the introduction of new technologies onto civil and military helicopter platforms has not always been a total success. While the System may have been effective in its conceived role it has sometimes introduced unforeseen human factors issues. Some major hazards in the past have included hypoxia, heat and cold, noised and vibration, and acceleration. At present, the major concerns are fatigue, spatial disorientation, night vision systems and protective garments. Some of the historical issues are also still with us. An illustration is shown of US Army spatial disorientation accident rates over the years.
Systems have always been limited by the inadequacy of human integration. To decrease workload and increase mission effectiveness is the aim but there are obstacles to human performance integration. These include competing budgets, poor identification of defining the requirement for integration early in the programme, decreasing manpower, and the work required for human-system integration.
What can be done is a system of standards and guidelines which includes a human engineering programme plan, test and evaluation, and flight simulation and flight testing. This encompasses laboratory work, simulation, and actual comparison of a new system directly with the one that it is replacing.
Dealt with by Heidi Castle of BAE Systems, this paper is concerned with the sensory cues relied upon during flight. These are audition (hearing), vestibular (balance), visual (sight), and haptic (touch). The pilot needs the last-named because the visual sense is becoming overloaded and it is necessary to be kept “in the loop”. Haptic sense is highlighted as a key alternative. Haptic sub-senses are tactile, surface texture, force, motion, position, temperature, and pain. Without the haptic sense we would feel paralysed and numb.
Haptic devices could provide the following stimulation: vibration, forced and pressure, electro stimulation, temperature, pain and discomfort, and tickle and itch. Early Haptic devices were developed from 1967-1989, the last named being the Exos Dextrous Hand Master. Now from Haptic technology is the CyberForce attached to CyberGrasp (Immersion Technologies and SensAble Technologies). Various equipments are available including the Motion Cue Seat of Cranfield Aerospace, the NLR G Seat, and the Combat Simulator from the University of Utah. Other technologies have appeared and the various controllers include the drive controller from BMW and others from Echo Flight, Logitech and Logan and Hayes. Sensory augmentation and substitution is provided and Tactile Situation Awareness System (TSAS) can stop spatial disorientation and haptic devices may help to stop motion sickness too. BAE Systems is researching the potential of haptic feedback for both navigation cues and targeting cues.
Advances in flight control technology
Given by Jeremy Howitt of QinetiQ and dealing with Primary Flight Control (PFCS), Automatic Flight Control, (AFCS), and Integrated Flight Control (IFCS) systems, the paper first considered PFCS technology status, which is essentially unchanged since the inception of the helicopter. However, technology trends include FBW and beyond. The advantages of FBW for rotary wing aircraft have traditionally been outweighed by the “Cons” but the balance is reversing due to a trend towards heavier rotorcraft with longer service life, tiltrotors, and rotary-wing unmanned air vehicles (UAVs).
The fundamentals of PFCS technology status has remained unchanged for many years and the trends now are for FBW (FEW) which reduce weight, improve reliability and maintainability and provide a foundation for enhanced AFCS function. The pros ands cons of FBW for rotary wing aircraft means that the former have traditionally been outweighed by the cons, but the balance is reversing. This is due to the trend towards heavier rotocraft with longer in-service life, tiltrotors, and rotary-wing UAVs. Beyond FBW, PFCS trends include “swashplateless” control via on-blade effectors, the FBW version of mechanical concept pioneered by Kaman, and further simplification of control mechanism with weight and through-life cost savings.
AFCS technology means that handling qualities and agility are traditionally a much stronger operational driver for fixed-wing compared to rotary-wing. The more demanding rotary-wing operational requirements are driving handling qualities and AFCS technologies. The trends for AFCS encompass the rationalisation of handling qualities standards/design guides and adoption of best practice from each, as well a more digital AFCS, bringing improved mission effectiveness and flight safety. The trends for IFCS retain the flight control system as a core element within the integrated vehicle management system (VMS), building on the trend toward open architecture avionics systems and integration of flight and engine control within VMS.
A summary of the main points includes the observation that more demanding operational requirements are driving the technology update. The benefits will include weight reduction and increased payload/range/endurance; improved reliability/maintainability and reduced through-life costs; and improved mission effectiveness and flight safety.
Non-visual sensory input/output
From Paul Collins of QinetiQ came this contribution which began with the observation that audio messages are no longer acoustically mixed in the pilot's head and the audio sounds as if it comes from spatially separate locations outside of the pilot' helmet. By direct voice input, the pilot can control cockpit systems by just using his voice. 3D audio (spatial location of sound) provides sound realism that could increase the pilot's eyes out time and improve his situational awareness. Audio messages are no longer acoustically mixed and are perceived at spatially separate locations outside of the pilot's earphones. Three-dimensional audio significantly improves the pilot's ability to listen torn and understand individual messages.
There are two 3D types; non-head tracked in which dynamic cueing is not possible and head-tracked where 3D audio is world or aircraft referenced. The former provides spatial separation of communication channels and reduces the risk of hearing damage, and with head tracking, also provides world referenced audio warnings, improves target acquisition, and improves navigation in addition to the other features.
Tests have shown 81 per cent improvement in audio intelligibility with 3D audio with head tracking. In a study at ARL Aberdeen, this type of 3D audio improved communications by providing spatial cues that enabled the pilot to listen to individual communications messages, reduce the noise, as well as the improvement in intelligibility. Head-tracked 3D has been the subject of flight demonstrations in a Lynx helicopter and the improvements predicted have been noted. It is considered that 3D audio brings many advantages with no downside effects.
Direct voice input (DVI) enables voice control of cockpit systems using speech recognition technology and there is no need for the pilot to let go of the flying controls. There are two main types of speech recognisers (1980s/1990s), the speaker-dependent and the speaker-independent. The latter is suitable for large vocabulary applications and is usable by any speaker. The primary benefits of DVI are that it provides alternative control of aircraft systems when pilot's eyes and hands are busy, by-passes complicated menu structures on multi-function cockpit displays and enables voice control of distracter tasks. It also reduces the number of switches and has the potential to reduce the number of LRUs in the cockpit. Flight experiments have been conducted with variable command wording which provides for a robust and easy to use DVI system and has a flexible design that accepts pilots' speech differences. Overall, DVI is a help with no hindrances.