WO2022208383A2 - Improving aircraft situational awareness - Google Patents

Abstract

The present disclosure relates to an instrument for an aircraft which is found to be particularly effective in alerting a pilot to departures from safe flight conditions and which is expected to reduce the incidence of accidents, particularly in less experienced pilots in high workload situations. It is particularly useful in helicopters but may be used in fixed wing aircraft also.

Description

IMPROVING AIRCRAFT SITUATIONAL AWARENESS

BACKGROUND

The present invention relates to improved systems for aircraft, both fixed wing and rotary.

Aircraft have been around for over a century and there have been numerous advances in aerodynamics and propulsion. Air safety has been significantly improved over the last few decades since the adoption of an approach viewing the pilot, the airframe and aircraft hardware, the instruments and the controls as a complex interacting system. In particular, it has been appreciated that the way an aircraft behaves in response to control inputs or provides information to the pilot can significantly increase or decrease the likelihood of human error being introduced or corrected. Thus, technical certification of aircraft considers not just how the aircraft systems operate in themselves but how they convey their operation to the pilot.

Initially aircraft were flown with a compass for direction and a stopwatch and estimate of speed to measure distance, with the view outside for orientation. To permit flying in poor weather, and to mitigate inaccuracies in a magnetic compass (particularly when turning) aircraft are usually equipped for instrument flight with an artificial horizon and gyro-stabilised compass.

However, notwithstanding the realisation some decades ago of the importance of the details of the pilot-aircraft interface, even with the advent of “glass cockpits” the basic instrumentation layout has changed little since the advent of the basic “six pack” of instruments, seen in Figure 1. The instrumentation and the use of it can be found in numerous textbooks on the subject, for example “The Art of Instrument Flying” by J. R. Williams 2^nd Edition 1991, the disclosure of which is incorporated herein by reference.

Pursuant to the invention it has been appreciated that aircraft instrumentation is understandably designed by and for highly experienced professional pilots. A significant proportion of accidents however are associated with pilots with relatively little experience of flying by reference to instruments alone encountering poor visibility unexpectedly. Since poor visibility is often associated with bad weather, such as gusts, turbulence, rain, thunder, such pilots may be highly stressed and less able to interact effectively with the aircraft. While training seeks to prepare pilots better, such accidents do occur frequently. A technical solution system which provides enhanced communication of aircraft situation to a pilot would be a significant improvement. Some proposals have attempted to augment controls by use of the autopilot functionality, particularly on larger aircraft with stick shakers or envelope protection but these have their own issues and limitations and can sometimes introduce problems.

SUMMARY OF THE INVENTION Pursuant to the invention from analysis of accident reports and behaviour of pilots in unusual situations, it has been appreciated that a significant improvement would be to provide a technical solution to cause a pilot to take in additional information in the situation where he or she has become stressed and “fixated” on a single instrument.

According to a first aspect, the invention provides an attitude instrument for an aircraft comprising a central display area which moves up and down in response to changes in aircraft pitch and rolls in response to aircraft roll, characterised by having a further indicator in the form of a ring around the central display area having marking indicating compass headings which rotates in response to changes in aircraft heading.

With this instrument, a pilot who is focussed on the artificial horizon, for example if struggling to keep the aircraft straight and level or to execute a controlled turn in poor weather is simultaneously given awareness of the aircraft heading and importantly any changes in heading and the rate of change without having to shift gaze.

One particularly important and serious condition this novel instrument can significantly assist with is the inadvertent spiral dive or graveyard spiral. This is believed to have been responsible for the death of John F Kennedy Jr and his family. In this condition, an aircraft nose is pointed slightly down and the aircraft is slightly banked. In a balanced aircraft there is no sensation of acceleration in such a condition and there is no immediate sign to alert the pilot all is not well. However, as the aircraft is pointed down the speed will increase and many aircraft may “fall into the turn” tightening the bank with or without inadvertent pilot commands. This can rapidly build up with increasing rate of turn and descent if unchecked to the point of overstressing the aircraft leading to structural failure or impact with terrain below.

However a pilot observing the novel instrument will notice the movement of the outer dial (experiments pursuant to the invention confirm the phenomenon that the eye picks up on movement much more effectively than a stationary dial) and this is found to trigger a response to the unexpected condition of the aircraft more effectively than relying on the pilot picking up cues from other instruments. In a preferred arrangement the instrument may have means for highlighting the direction indicator ring to signify an alert condition. This alert condition may be a deviation from an intended heading or a rate of change of heading above a preset rate.

The instrument may be provided as a mechanical instrument using a conventional arrangement to drive the artificial horizon portion and a motor to drive the rotating ring similar to the arrangement on a conventional rotating card Dl (direction indicator) or HSI (horizontal situation indicator).

In an alternative the instrument may be provides as an electronic display ring overlaid on a conventional mechanical AH (artificial horizon). In a further alternative the entire instrument may be provided as graphics on an electronic display. This may be provided as an individual instrument display.

In a particularly advantageous arrangement, the instrument is provided as a graphical overlay on a larger graphical display, the larger graphical display providing additional situational information, for example a moving map or terrain chart or navigation chart or hazard alerting system or real or synthetic visible or infra-red camera view.

In accordance with a second aspect the invention provides an instrument display for an aircraft comprising a graphical representation of external terrain having an attitude instrument according to the first aspect or any preferred feature thereof overlaid thereon. Additionally or alternatively, the display may include an altitude instrument according to the third aspect and/or a power instrument according to the fourth aspect. Most advantageously the instrument display includes two and preferably three of said instruments overlaid substantially side by side and preferably three, preferably with the attitude instrument central.

Preferably the instruments are overlaid at least partially transparently. Preferably the transparency is adjustable. In a third aspect the invention provides an altitude instrument for an aircraft comprising a generally circular instrument face having a rotating altitude indication arranged around a first portion of the circumference with an enlarged or highlighted portion indicating the current altitude numerically, wherein the markings on the first portion move in response to changes in altitude and an indication of rate of change of altitude up or down on a second portion of the circumference.

Advantageously the the first and second portions each comprise substantially half the circumference. This is found to aid pilot communication of both altitude and rate of change of altitude. Preferably the portions are located as left and right portions. Advantageously the rate of change portion further includes a needle or bar indicating rate of change. The instrument advantageously includes an altimeter subscale within the circumference.

It is found that this instrument can convey to pilots a better appreciation of deviations in altitude more rapidly as well as giving an immediate readout of current altitude. With conventional needle based altimeters it is possible to see changes by movement but an instantaneous reading is difficult whereas tapes allow altitude to be read accurately but become difficult to read during rapid movement. Having the VSI effectively present in the same instrument greatly increases situational awareness and it is found that this curved circumferential display is surprisingly more effective than a simple up/down bar next to a tape.

In a fourth aspect the invention provides a power instrument for an aircraft comprising a central portion indicating in a linear bar the rotational speed of at least one of a power plant component or turbine and/or a propellor or rotor or a turbine and in a circumferential display around the central portion a computed indication of total power as compared to a determined limit.

This instrument is found to be particularly effective as the pilot can observe total power as compared to maximum available and simultaneously note RPM. It is particularly helpful in rotorcraft such as helicopters as any changes in RPM can be correlated instantly with power being produced. In a fifth aspect the invention provides a computer program or computer program product or logic arranged to produce a display according to any other aspect.

Preferred features of aspects may be combined.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will be described, by non-limiting example only, with reference to the following drawings:

Fig. 1 shows an exemplary conventional instrument arrangement;

Fig. 2 shows an exemplary attitude instrument according to an embodiment of a first aspect; Fig. 3 shows an instrument panel for an aircraft according to an embodiment of a second aspect;;

Fig. 4 shows an exemplary altitude instrument according to an embodiment of a third aspect; Fig. 5 shows an exemplary power instrument according to an embodiment of a fourth aspect;

Fig. 6. Shows a block diagram of an embodiment of the operation of a processor for providing the display where the instruments are electronically provided. DETAILED DESCRIPTION

The examples and conditional language recited herein are intended to aid the reader in understanding the principles of the present technology and not to limit its scope to such specifically recited examples and conditions. It will be appreciated that those skilled in the art may devise various arrangements which, although not explicitly described or shown herein, nonetheless embody the principles of the present technology and are included within its scope as defined by the appended claims.

Furthermore, as an aid to understanding, the following description may describe relatively simplified implementations of the present technology. As persons skilled in the art would understand, various implementations of the present technology may be of a greater complexity.

In some cases, what are believed to be helpful examples of modifications to the present technology may also be set forth. This is done merely as an aid to understanding, and, again, not to limit the scope or set forth the bounds of the present technology. These modifications are not an exhaustive list, and a person skilled in the art may make other modifications while nonetheless remaining within the scope of the present technology. Further, where no examples of modifications have been set forth, it should not be interpreted that no modifications are possible and/or that what is described is the sole manner of implementing that element of the present technology.

Moreover, all statements herein reciting principles, aspects, and implementations of the technology, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof, whether they are currently known or developed in the future. Thus, for example, it will be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative circuitry, graphics or mechanical arrangements embodying the principles of the present technology. Similarly, it will be appreciated that any flowcharts, flow diagrams, state transition diagrams, pseudo-code, and the like represent various processes which may be substantially represented in computer- readable media and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

It will be clear to one skilled in the art that many improvements and modifications can be made to the foregoing exemplary embodiments without departing from the scope of the present technology. As can be seen in Fig. 1 , a typical conventional aircraft instrument panel 10 has primary instruments comprising an artificial horizon (AH) 12 usually in the top centre of a T formation with a direction indicator (Dl) 14 below, an airspeed indicator (ASI) 16 to the left and an altimeter 18 to the right. Usually completing the “six pack” there is a turn and bank or turn and slip indicator 22 indicating rate or turn and a balance ball and a variometer or vertical speed indicator (VSI) 20 completing the set. These instruments collectively give a pilot all the information necessary to fly the aircraft (whether fixed wing or rotary) to maintain a desired heading, altitude and attitude.

In addition there are various engine and system instruments such as an RPM indicator 30, manifold pressure indicator 32, fuel gauges 34, exhaust gas temperature guage 36, oil temperature and pressure 38 and current and vacuum gauges 40 to monitor the engine and system function.

In addition there are radios 50 and navigation equipment including a transponder 52 and VOR indicator 54.

In instrument flight in instrument meteorological conditions (IMC) when there is no view outside the window of a horizon to give an instinctive visual cue as to the aircraft orientation and heading the pilot must studiously and frequently scan all these instruments while also attending to navigation, radio frequency settings, monitoring the engine condition and fuel situation and other tasks. Pilots are trained to do this and with an experienced trained pilot in normal conditions this is feasible, albeit requiring concentration. However particularly for an inexperienced pilot in a stressful situation, or when preoccupied with another task or an urgent situation, for example having to re-route or cope with turbulence, evidence suggests the scan deteriorates and may only take in a few instruments or infrequently take in some and in addition the pilot may not correlate the information effectively. For example consider a pilot running into unexpected bad weather such as a sudden icing cloud and beginning to plot a diversion, a pilot action sequence might be as follows (it being appreciated that some of this may be partially learned or automatic and some may be more conscious) --start

*Observe AH and correct attitude Check chart and start plan weather diversion Tune radio *Note altimeter Continue planning route

Continue tuning radio *Check Dl

Continue plotting route Attempt radio call *Observe AH and correct attitude

Check chart Retry radio call

*Observe engine instruments all OK Note ice forming on windshield Switch on de-icing equipment

*Check Dl --continue

In a rotary wing aircraft such as a helicopter, the aircraft is intrinsically unstable so more likely to diverge rapidly from level flight if un-commanded and the pilot generally has the right hand on the cyclic and the left hand on the collective and has to manipulate charts and radios and note down clearances with one of those hands so there can be a high workload. Even for non-pilots it can be appreciated that failing to notice a slight discrepancy between heading readings between successive glances at the heading indicator might occur. Referring now to Fig. 2 a novel instrument according to a first embodiment will now be described, by way of example only.

An instrument 100 has an artificial horizon indicator 102 which in this embodiment has graduated pitch lines 104 indicating increments of pitch above and below the horizon. In this example major pitch lines are marked at 10 degrees and minor lines are visible at 5 degrees but any conventional arrangement or variant thereof may be used, for example including a blue or cyan sky upper section and a brown or dark ground section and smaller pitch increments may be marked.

In one embodiment, this portion of the display may be provided by a physically moving card, moved by servo motors either driven from an external gyro reference or a gyro reference within the instrument. Where the instrument includes free moving gyros, an optional control 10g may be provided to cage the gyros to prevent toppling and/or to reset for example during aerobatic manouevres. Any features known in conventional artificial horizons may be used for this portion of the instrument. In an alternative embodiment, the central portion may be provided by a graphical display which may be LCD, preferably backlit or OLED or any suitable display technology, with a processor arranged to provide the appropriate graphical arrangement on the screen similar to a conventional physical display.

Around the artificial horizon display portion is provided a heading reference ring 110. Importantly this rotates independently of the artificial horizon. In embodiments where both are provided by physical moving components a gap 114 is present between the two to permit movement. Both the AH component and the heading ring component may be provided by graphics on a continuous display but even when provided in such a form it is preferably that a visible gap 114 is seen between the two. Markings on the heading ring may follow conventional compass card markings, and may include either or both letter indications of NSEW for compass points and numbers for headings.

Particularly where the heading ring is provided by a graphical display the current heading may optionally be shown highlighted 112 with enlarged lettering and/or brighter illumination or changed colour. With a moving dial the heading may be highlighted with a suitable indicator and/or illumination.

As a further aid to situational awareness, in some embodiments one or more further indicators 116 may be provided on the heading ring to display additional information. In this case a wind indicator is provided as an arrow in contrasting colour pointing in the wind direction with a number indicating the windspeed (in knots). This is found to improve situational awareness particularly for helicopter pilots manoeuvring close to the ground.

A further indicator may be provided (not shown) to indicate a desired track or heading, in the manner of a known heading bug. The North marker 118 may be highlighted, for example in a different colour - this is found to give a pilot a rapid awareness of orientation in difficult situations.

As a further optional but advantageous feature in some embodiments a balance ball or slip indicator 120, which may be a mechanical indicator or a graphical indicator driven by a processor from a balance sensing arrangement may be provided. Whether the indicator is mechanical or electronically provided or a mixture of components, it may be arranged to highlight (for example graphically or by coloured backlight) a condition suggesting pilot attention is required, for example the AH may brighten and/or change colour if the attitude changes in a manner indicating a departure from normal flight (for example a pitch up or down above a threshold or a bank angle exceeding a threshold). Additionally or alternatively the heading ring may brighten and/or change colour if the heading diverges from a planned heading by more than a threshold value and/or the rate of change of heading indicates a rapid change.

A particular advantage is that this instrument can be relatively compact but instantly communicate critical information to control aircraft attitude more effectively than conventional instruments

Referring to Fig. 3, in an optional but advantageous embodiment, an enhanced instrument panel display 200 for an aircraft is provided. The instrument 100a is provided as a virtual instrument graphically superimposed on an image 202 where the image is selected from a chart representation, a terrain representation, a synthetic 3D representation, a camera image, or a combination or selection from a real camera image and a virtual terrain representation.

Whereas overlaying conventional instruments on such an image would detract from readability, by virtue of the enhanced pilot communication provided by this instrument a single instrument can be provided leaving clear areas around. The instrument display has an optional hazard highlighting indication 210 (here shown highlighting power lines).

It can display a current radio frequency 220. An enhanced fuel indicator 230 displays fuel advantageously with a bar indicting fuel level and optionally a percentage full and preferably also displays fuel flow rate and endurance at current flow and distance to run at current flow and airspeed, or alternative such parameters.

Additional instruments 240 may display parameters relating to electrical and/or engine or other system health such as generator current, battery voltage, oil pressure, oil temperature.

It is advantageous also to display undercarriage status 250.

Also shown in Fig. 3 are an altitude instrument 300a according to a third aspect and a power instrument 400a according to a fourth aspect, as will be described below. Referring to Fig. 4 an altitude instrument 300 comprises within the circumference a numerical readout of altitude 302 which corresponds to the instantaneous altitude 304 displayed on a generally circular circumferential tape 306 occupying the right hand half of the circumference. On the left hand portion a rate of change 310 is displayed at the end of a bar 314 on a circular tape 312 indicating rate of change. The altimeter setting 320 and units 322 are shown within the circumference. This is found to be particularly effective in informing a pilot of all relevant altitude information including alerting to rapid changes.

Referring to Fig. 5 a power instrument 400 displays a computed total power 402 which also corresponds to the position of a circular needle or bar 404 on a circumferential ring 406 which may also include coloured (ideally amber or yellow and red) temporary maximum power regions. In this example for a rotorcraft engine RPM 410 and rotor RPM 412 are presented as two linear bars or tapes as percentage of target or maximum. This is found to be particularly effective in informing a pilot of all relevant power information including alerting to rapid changes.

The power instrument includes (within the instrument or remotely) a processor for storing target values for RPM and, in the case of a turbine, torque and computing power as a percentage of a target power. The power instrument further includes logic storing target main rotor RPM for a rotorcraft and computing percentage of target. The display is preferably integrated within an aircraft and communicates with aircraft systems to display further parameters, as can be seen. The display may be coupled to an input arrangement as described in our earlier filed UK patent application number 2013139.7, the disclosure of which is incorporated herein by reference for the purpose of explaining the input arrangement.

Referring to Fig. 6 the general operation of the system will not be described. These steps may be performed in different orders and maybe performed by different subcomponents, which may be linked in sequence or may operate asynchronously each providing updated data to be used as it becomes available, for example on a common communication bus.

In a step 602 the aircraft attitude is determined from acceleration and gyro sensors.

In a step 604 the aircraft heading is determined from a compass sensor, which may have software applied to stabilise the heading, or from a gyro stabilised heading source.

In a step 606 the engine parameters are determined. For a turbine these may be N1, power turbine rpm, torque, and various inter-turbine temperatures, for example from a FADEC controlling the engine, and a percentage of total power may be computed. If parameters are at or approaching limits (temperature or torque or N1) an additional alert may be generated, for example a pop-up or a change of colour on the display and/or an audible warning.

In step 608 the aircraft altitude is determined from barometric instruments. This may be cross-checked with altitude from a GPS source and in the event of a gross error (for various reasons barometric will not necessarily be the same as GPS altitude) suggestive of parometric instrument failure, an alert may be generated. In step 610 GPS position is determined.

In step 612 a synthetic 3D view is produced from stored chart and terrain data based on aircraft position, altitude and heading. This may wholly or in part be augmented or substituted by camera data, whether visible or IR.

In step 614 updated instruments are overlaid on the display. In step 616 hazards, such as cables, high points, controlled airspace, restricted areas, which may be user selectable, are identified from stored chart data. In step 618 they are highlighted if present on the display area, for example by displaying in a contrasting colour. In Figure 3 power lines are shown highlighted in red.

It will be clear to one skilled in the art that many improvements and modifications can be made to the foregoing exemplary embodiments without departing from the scope of the present technology.

Claims

1. An attitude instrument for an aircraft comprising a central display area which moves up and down in response to changes in aircraft pitch and rolls in response to aircraft roll, characterised by having a further indicator in the form of a ring around the central display area having marking indicating compass headings which rotates in response to changes in aircraft heading.

2. An instrument according to any preceding claim including a further indicator on the circumference indicating wind direction and/or speed.

3. An instrument according to any preceding claim arranged to highlight the heading corresponding to current heading.

4. An instrument according to any preceding claim wherein the North point of the compass ring is highlighted.

5. An instrument according to any preceding claim including a balance or slip indicator in the central display area.

6. An instrument according to any preceding claim arranged to highlight the direction indicator ring and/or the central portion to signify an alert condition.

7. An instrument according to any preceding claim including a visible space between the central display area and the ring and wherein the ring rotates independently of the central display area.

8. An instrument according to any preceding claim including a mechanical moving component as at least one of the central display area and/or the ring.

9. An instrument according to any preceding claim including a multi-pixel display for displaying a graphical representation of an indicator as at least one of the central display area and/or the ring.

10. An instrument according to any of Claims 1 to 7 wherein both the central portion and the ring are provided as graphics on an electronic display.

11. An instrument according to Claim 9 provided as a graphical overlay on a larger graphical display, the larger graphical display providing additional situational information, for example a moving map or terrain chart or navigation chart or hazard alerting system or real or synthetic visible or infra-red camera view.

12. An altitude instrument for an aircraft comprising a generally circular instrument face having a rotating altitude indication arranged around a first portion of the circumference with an enlarged or highlighted portion indicating the current altitude numerically, wherein the markings on the first portion move in response to changes in altitude and an indication of rate of change of altitude up or down on a second portion of the circumference.

13. An altitude instrument according to Claim 12 wherein the first and second portions each comprise substantially half the circumference.

14. A power instrument for an aircraft comprising a central portion indicating in a linear bar the rotational speed of at least one of a power plant component or turbine and/or a propellor or rotor or a turbine and in a circumferential display around the central portion a computed indication of total power as compared to a determined limit.

15. An instrument according to Claim 14 for a turbine-powered aircraft arranged to compute total power from turbine RPM and torque.

16. An instrument according to Claim 14 or 15 for a rotorcraft arranged to display main rotor RPM as a percentage of a target RPM and a power turbine RPM as a percentage of a target RPM.

17. An instrument display for an aircraft comprising a graphical representation of external terrain having at least one of an attitude instrument according to Claim 9 or 10 or an altitude instrument according to Claim 12 or 13 or a power instrument according to any of Claims 14 to 16 overlaid thereon.

18. An instrument display according to Claim 17 having 3 such instruments overlaid, preferably with the attitude instrument central and raised and the others on either side.

19. Ain instrument display according to Claim 17 or 18 further including at least one of an airspeed indicator in the form of a bar or linear indication, preferably horizontally below said instruments and/or a fuel quantity indicator.

20. An instrument according to any of Claims 17 to 19 wherein the instruments are overlaid at least partially transparently.

21. An instrument according to any of Claims 17 to 20 including logic for highlighting a hazard on the graphical representation.

22. A computer program or computer program product or logic arranged to control a display according to any preceding claim.

23. An aircraft comprising an instrument according to any of Claims 17 to 21 and further comprising logic for displaying further aircraft system parameters on the graphical display.

24. An aircraft according to Claim 23 wherein the display panel is an irregular shape adapted to fit the cockpit of the aircraft.

25. An aircraft according to Claim 24 wherein the aircraft is a helicopter and includes a remote data entry device adjacent the collective control for entering information controlling system parameters or otherwise affecting the display.