Variable Priority Cockpit Warning and Display System

Technical Field

The present invention relates to a warning and display system for an aircrafl cockpit and more particularly lo an improved system for upgrading or varying the priority level of various displays and audible signals within an aircrafl cockpit depending on Ihe aircraft operating environment and equipment status.

Background of Ihe Invention Aircraft cockpit control panels typically display various items of information for a pilot to view. Each of the informational ilems is in a distinct location, and each location has a vaiying level of impoilance so that Ihe pilot knows how impoitant the informational item or message is by its location on the panel. Additionally, informational ilems or messages are color coded, based on their importance, with green being advisory, yellow being caution, and ted being warning, further advising Ihe pilol of Ihe priority level of Ihe message.

Fig. 1 shows an example of the current methods of displaying information or messages lo a pilot. In the example of Fig. 1 , an "External Power Connected" advisoiy indicator 15 is shown as being displayed when an external power connector 22 is attached lo an aircraft receptacle 20. I he priority level of the "External Power Connected" advisory message does not change in response lo a change in aircrafl status, and therefore if the aircrafl is idle or if the aircraft begins to laxi or take off, the message will continue to have the same priorily.

I he failure to change the priority of coc kpit indicators in response lo changes in aircrafl operational status poses a pioblem with respecl lo green advisory lights that are a low priorily, and therefore, are sometimes missed or ignored by pilots. II is sometimes even common practice to fly with some advisory lights on, such as a "De Ice System

On" light. It is therefore possible for a pilol lo negligently or inadvertently ignore an "External Power Connected" advisory light, a

"Gust Lock On" advisory light or other advisory lights and attempt to take off with ihe advisory condition in existence. Under these circumstances, a great deal of damage may occur to ihe aircrafl or external equipment when the aircraft changes operational mode fiom ground idle to taxi or take off.

Summary of the Invention

Objects of the invention include the provision of an improved cockpit warning and display system for varying or upgrading the priority level of aircrafl cockpit displays and aircraft cockpit audible signals based on changes in the aircraft operating environment and changes in equipment status.

According lo ihe present invention, aircrafl equipment status is monitored, and in response to changes in ihe operational status of the aircraft for a given equipment status, ihe priority level of cockpit audible and visual messages and indications are modified to attract the attention of a pilot when pilot action is required.

In further accord with the present invention, information may be displayed lo Ihe pilot that indicates specific aclions needed lo downgrade the priorily level of Ihe cockpit message/indication. T he piesent invention provides a significant improvement over

Ihe prior art because cockpit indications aie modified not only based on equipment status, but also based on the aircraft operating environment. T herefore, a situation that is benign or even desirable under one set of operating conditions is given a low priorily and the same situation may be given a high priority when the operational status of Ihe aircraft changes such that pilot action is required. T herefore, the invention provides indications thai are based not only upon the degradation or operation of the syslem itself, but also on other opeialing conditions. The foregoing and other objects, features and advantages of the present invention will become more apparent in light of ihe following detailed description of exemplary embodiments thereof, as illustrated in the accompanying drawings.

Brief Description of the Drawings

I ig. I is a sc hematic block diagram of a prioi ait cockpit warning and display syslem;

Tig. 2 is a schematic bloc k diagiam of an aiicraft cockpit warning and display system of the piesenl invention;

Tig. 3 is a schematic block diagram of an aiiciafl mission equipment package foi implementing the cockpit warning and display system of Fig. 2;

Tig. 4 is a logic flow diagram of a louline implemented by mission equipment package of Tig. 3 foi implementing the cockpit warning and display syslem of Ihe present invention; and

Tig. 5 is an alternative embodiment of the logic flow diagram of Tig. 4.

Best Mode for Carrying out he Invention

Ihe piesent invention provides an iinpioved cockpit warning and display syslem having indications the piioiity levels of whic h change in response lo changes in aii raft operating environment. Foi ease of desciiption and understanding, Ihe system of ihe present invention will be described with lespect lo Ihe cockpit indications for an external power connection on a helicopter. I lowever, Ihe syslem of Ihe piesent invention is applicable lo any aiiciafl indication the piioiity level of whic h changes in response to changes in the airciaft operating environment, as will be described in giealer detail heieinafter. Refeiring to Fig. 2, a helicopter (not shown) is piovided with a leceptac le 20 for receiving an external powei connection 22. lypically, when a helicopter is secured in a non-opeiational (static) condition, e.g., landed, sloiecl, tied-down, etc., with the engines turned off, exleinal power is supplied to the helicopter via the external connection 22 and receptac le 20 lo power elec li ic al and avionics systems without dischaiging Ihe helicopter's sloiage batteries (not shown).

It is desirable to vaiy the piiorily level of Ihe cockpit "Exleinal Power Connecled" indication based on the opeiational status of the helicopter. When ihe helicopter is static, a normal condition exisls when external power is being supplied to the helicopter, and Iherefoie it is desiiable to piovide the pilot with only an advisoiy indication that the

external powei is connected. I he advisoiy indication is lypically indicated by a gieen light on a helicoptei Caution/Advisory panel. If Ihe helicopter engines aie operating with Ihe main 10I01 rotating at a speed above a thieshold speed, it may be desiiable to upgiade fiom the advisoiy indication to a caution indication. Foi purposes of describing the present invention, if the helicopter lotor speed (NR) is gieatei than 80% of rated speed then the External Power Connected indication is upgraded fiom an advisoiy indication lo a caution indication. T he caution is lypically indicated by a yellow light on Ihe Caution/Advisory panel. It is desiiable lo upgiade ihe External Powei Connected indication fiom advisoiy to caution when rotor speed is grealei than 00% of its rated speed because Ibis change in helicopter opeiational status is indicative of the helicopter prepaiing lo take off. If ihe helicoptei continues lo operate with roloi speed giealer than 80% of ils laled speed, and eilher the wheel brakes aie leleased or an indication is piovided thai the weight is off Ihe helicoptei wheels, then the piioiity level of Ihe External Power Connected indicatoi is incieased from caution to warning. A warning indication is lypically a led light on the cockpil Master Warning panel. A warning indication is piovided nuclei these conditions because if the external power cable is still connected lo

Ihe helicopter when il is taxiing or taking off, significant damage may occur to the helicoptei oi Ihe external power supply.

Referring to Figs. 2 and 3, a helicopter mission equipment package (MEP) 35 leceives signals indicative of helicoptei operational status and equipment slalus for conliolling the cockpit indications for the external power connection. A flight control segment (rCS) 37 piovides the MEP 35 a ledundanl weight on wheels indication and a lotoi speed signal, and an aiiframe segment 40 provides the MEP 35 an indication of the paiking biake status and the exleinal powei connection slalus via an Air Vehicle Inleiface and Contiol (ΛVIC) unit 43. l ypically, Ihe flight control segment sensors inc lude triple redundant sensois lo develop the rotor speed signal and the weight on wheels signal. T he aiifiame sensois use a ground isolation resistive ciicuit appioach lo enable Ihe AVIC units to detect aiiframe open-ciicuit and giouncl faulted wiring. T he flight control segment 37 and AVIC unit 43 provide a mission computer 48 with a validity bit lo indicate that each signal is acceptable

for use. The mission computer 48 performs Ihe subroutine of Fig. 4 for providing cockpit displays 52, e.g., the cockpit Caution/Advisory panel or Master Warning panel, with Ihe appiopriale external power connection indication. Still refeiring lo Tigs. 2 and 3, when the mission computer 48 receives an indication that ihe external power connector is installed, it checks Ihe slalus of Ihe main rotor, the paiking brake, and the weight on wheels signal lo determine the appropriate cockpit indication. If Ihe lolor speed is less than 80%, a first switch 50 is closed lo thereby provide the cockpit with an advisory indication 53 foi Ihe external power connection. If the rotor speed is greater than 80% of its rated speed and the paiking brake is engaged and ihe helicopter weight is on its wheels, then a second switc h 57 is closed lo thereby provide a caution indication 59 for Ihe external power connection. Addilionally, a "SI IUT OFF ENGINE, REMOVE EXTERNAL POWER PLUG, SECURE

EXT ERNAL POWER ACCESS DOOR" message may be displayed lo the pilot on Ihe Caution/Advisory panel to indicate ihe action lequired lo terminate ihe external power connection before laxiing oi lake off of ihe helicopter. Finally, if the helicopter rotor speed is greatei than 80% of its rated speed and either Ihe paiking brake is released or ihe weight is off Ihe wheels, a third switc h 64 is closed to provide a warning indication 67 for Ihe exleinal power connection on the Master Warning panel. Also, either an "APPLY PARKING BRAKE" or "RET URN TO GROUND" message is displayed on Ihe Caution/Advisory panel along with the message indicating that the external power connection should be seemed.

The mission computer 48 performs the subroutine of Tig. 4 for controlling Ihe external power connection indication on the cockpil displays 52. Referring lo Fig. 4, the routine is entered in a step 100, and the mission computer chocks if the external power connector is attached in a lest 102. If the results of the tests 102 aie negative, then no external power connection indication is required and a step 105 is performed wherein switches 1, 2, and 3 are opened. T he subroutine then returns in a step 109. If the results of the test 102 are positive, then ihe external power connection is attached, and a test 1 12 is pei formed wheiein the mission

computer checks if lolor speed is giealer than 80%. If the results of the test 1 12 aie negative, then a step 1 15 is peifoimecJ wheiein switch I is closed, switch 2 and 3 aie opened to iheieby piovide an advisory indication foi Ihe external power connection. T he subroutine then returns in Ihe step 109. I lowever, if ihe lesults of Ihe lest 1 12 aie positive, a lest 1 17 is peifoime wherein the mission computer checks if ihe paiking brake is released. If Ihe results of the test 1 1 7 are negative, a lest 1 19 is pel formed wheiein ihe mission computer checks if the helicopter weight is off Ihe wheels. If Ihe lesults of Ihe lest 1 19 aie also negative, then a step 121 is peifoimed wheiein switch 2 is closed and switch 1 and 3 are opened to thereby piovide a yellow caution advisoiy on the Caution/Advisory panel. Next, a slop 122 is performed wheiein Ihe "SI IU I OFT ENGINE, REMOVE EX I ERNAL POWER PLUG, SECURE EX I ERNAL POWER ACCESS DOOR" messages aie displayed to the pilot on the Caution/Advisory panel 52. The subroutine then returns in the step 109.

If the results of the test 1 17 are positive, external power is connected with rotor speed greater than 80% of NR and Ihe paiking biake is released. T heiefore sleps 123 and 125 are consecutively perfoimed wheiein the message "APPLY PARKING BRAKE" is displayed on the Caul ion/Advi soi y panel and switch 3 is closed and switc h I and 2 aie open to Iheieby provide a warning indication on the Master Warning panel. Next, step 122 is peifoimed wheiein Ihe pilot is instructed lo secure the external power connection. The subroutine then returns in the step 109. Similarly, if Ihe results of the test 1 19 aie positive, steps

124 and 125 are consecutively performed wheiein Ihe message "RE I URN T O GROUND" is displayed on Ihe Caution/Advisory panel and switch 3 is closed and switch 1 and 2 aie open lo thereby provide a warning indication on ihe Master Warning panel. Next, slep 122 is peifoimed wheiein the pilol is instructed lo secuie Ihe exleinal power connection. The subroutine then returns in the slep 109.

I he External Power Connection example described thus far is intended lo be exemplary, however, a more sophisticated syslem may be provided if desiied. For example, ihe syslem has been described thus far as having only two equipment status conditions, i.e., external power not installed or external power installed. A thiid equipment status may

include an external power installed condition with an accompanying low voltage or low cuiient condition. In this case, it may be desiiable lo increase Ihe External Power Connection indication piioi ity level fiom advisoiy lo caution so thai an operaloi may take appiopriale action to pi event dischaige of the aircraft's stoiage batleiies. This type of indication can be used in conjunction with the piesent invention as illustrated in Fig. 5. Refening lo Tig. 5, steps and lest 150 Ihiough 152 have been added lo piovide a caution indication in i espouse to ihe external powei supply voltage falling below a threshold voltage. T he subroutine illustrated in Fig. 5 still provides the desiied change in

External Power Connection indication priorily level in response to a change in helicopter operational status.

T he invention has been described thus far with lespecl lo the External Power Connected indication on Ihe cockpit display panels. I lowever, the invention is applicable lo any airciafl indication the priority level of which should change in response lo changes in aircrafl operational status. In T able 1 below, several examples of cockpit indications aie piovided together wilh the applicable piiority level and corresponding aircrafl operational status:

TABLE 1

T he invention was described as using a cockpit Caution/Advisory panel and Master Warning panel for providing the pilot with various indications and messages. However, any suitable panel or display may be used wilh Ihe present invention such as a warning panel, multifunction display panel, master warning panel, etc. All that is required is thai ihe pilol be provided wilh appiopriale indications ihe prioiily level of which change in response lo changes in aircrafl operating status.

Although the mission equipment package was described herein as receiving information indicative of aircraft operational status from the

aiiframe segment via an Air Vehicle Inleiface and Conliol unit and the flight conliol segment, any suitable method of pioviding infoimation indicative of aiicraft opeiational status may be used in accoidance wilh the piesent invention. Tor example, sensois may piovide signals indicative of aircrafl opeiational status diieclly to the mission computer.

Addilionally, ihe mission equipment package was described herein as comprising a mission computer containing subroutines such as Ihe subroutine of Tig. 4 for vaiying the piioiity level of vaiious displays and audible signals in response lo changes in aircrafl opeiational status. I lowevei, the indication conliol of Ihe piesent invention may also be implemented using equivalent dedicated digital or analog hardware, as is well known in the ait.

It may be desirable to piovide an audible alarm oi audible instructions lo the pilot in response lo certain caution or warning indications. The alarm may be a lone or other suitable audible signal lo altracl the pilot's attention. T he instructions may be recoided on an audio tape or be a computer generated audio message to provide the pilol wilh appiopriale instructions in response lo a caution or warning indication. Although the invention has been described and illustrated with respect lo exemplary embodiments thereof, it should be undei stood by those skilled in Ihe ail that Ihe foiegoing in vaiious oilier changes, omissions and additions may be made therein and thereto, without departing from ihe spirit and scope of ihe present invention.