GB2141683A - Warning system for tactical rotary wing aircraft - Google Patents
Warning system for tactical rotary wing aircraft Download PDFInfo
- Publication number
- GB2141683A GB2141683A GB08412991A GB8412991A GB2141683A GB 2141683 A GB2141683 A GB 2141683A GB 08412991 A GB08412991 A GB 08412991A GB 8412991 A GB8412991 A GB 8412991A GB 2141683 A GB2141683 A GB 2141683A
- Authority
- GB
- United Kingdom
- Prior art keywords
- warning
- aircraft
- airspeed
- altitude
- approximately
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C5/00—Measuring height; Measuring distances transverse to line of sight; Levelling between separated points; Surveyors' levels
- G01C5/005—Measuring height; Measuring distances transverse to line of sight; Levelling between separated points; Surveyors' levels altimeters for aircraft
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Emergency Alarm Devices (AREA)
- Radar Systems Or Details Thereof (AREA)
- Traffic Control Systems (AREA)
- Arrangements For Transmission Of Measured Signals (AREA)
Abstract
A warning system for rotary wing aircraft that monitors the altitude above ground of the aircraft and issues a warning when there is insufficient terrain clearance. The warning criteria are optimized for rotary wing aircraft and are altered as a function of landing gear position and airspeed. Two distinct warnings are given. One indicates insufficient terrain clearance and the other warns the pilot if he attempts to land with the landing gear up. Logic circuitry is provided to modify the criteria necessary to generate a warning, and to inhibit certain warnings, as required by the mode of operation of the aircraft. <IMAGE>
Description
SPECIFICATION
Warning system for tactical rotary wing
aircraft
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates generally to ground
proximity warning systems, and more particu
larly to a ground proximity warning system for
providing the pilot of a rotary wing aircraft with a warning in the event of insufficient terrain clearance, or if a landing with the
landing gear up is attempted.
Description of the Prior Art
Systems for providing the pilot of an aircraft with a warning in the event of insufficient terrain clearance or if a gear up landing is attempted are known. Examples of such systems are disclosed in United States Patent
Nos. 3,934,221, 3,934,222, 3,949,968 and 4,030,065 assigned to the assignee of the present invention.
While these systems do provide warnings in the event of insufficient terrain clearance, these systems are designed primarily for use with transport aircraft, and are not readily applicable to rotary wing aircraft whose flight and operational characteristics are substantially different than those of transport aircraft.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide a warning system that overcomes many of the disadvantages of the prior art warning systems.
It is yet another object of the present invention to provide a warning to the pilot of a rotary wing aircraft in the event of insufficient terrain clearance.
It is yet another object of the present invention to provide a warning system that warns the pilot of a rotary wing aircraft if he attempts to land with the landing gear up.
It is yet another object of the present invention to provide a warning system for alerting the pilot of a rotary wing aircraft of an insufficient terrain clearance condition wherein the warning criteria are optimized for the performance and operational characteristics of rotary wing aircraft.
Therefore, in accordance with a preferred embodiment of the invention there is provided a system that monitors the altitude above ground and airspeed of the aircraft and generates a voice warning such as "TOO LOW
TERRAIN" when the altitude above ground of the aircraft is insufficient for the airspeed at which the aircraft is flying. The criteria required to generate a warning are modified when the landing gear is up, and a second distinct warning such as "TOO LOW GEAR" is generated if the pilot attempts to land with the landing gear up.
DESCRIPTION OF THE DRAWING
These and other objects and advantages of the present invention will become readily apparent upon consideration of the following detailed description and attached drawing, wherein:
FIG. 1 is a logical block diagram of the portion of the system according to the invention that generates a warning in the event of insufficient terrain clearance;
FIG. 2 is a graph illustrating the relationship between the airspeed of the aircraft and the altitude above ground required to generate a warning when the landing gear is up; and
FIG. 3 is a graph illustrating the relationship between the airspeed of the aircraft and the altitude above ground of the aircraft required to generate a warning when the landing gear of the aircraft is down.
DETAILED DESCRIPTION OF THE PRE
FERRED EMBODIMENT
Referring now to the drawing, with particular attention to FIG. 1, there is illustrated an embodiment of the insufficient terrain clearance portion of the warning system according to the invention generally designated by the reference numeral 10. The system 10 according to the invention is illustrated in FIG. 1 in logical block diagram form as a series of gates, comparators, flip-flops and the like for purposes of illustration; however, it should be understood that the actual implementation of the system can be other than as shown in
FIG. 1, with various digital and analog implementations being possible.The signals used by the warning system as described include radio altitude and airspeed along with a signal representative of the position of the landing gear, various discrete signals indicating the mode of operation of the aircraft, for example, tactical or non-tactical or mine counter measures (MCM), and various validity signals.
Depending on the type of aircraft in which the warning system is installed, the signals shown in FIG. 1 can be obtained from individual instruments such as a radio altimeter 12, an airspeed signal source 14, such as, for example, an air data computer or an airspeed indicator, and various discrete elements such as a switch indicating the position of the landing gear, a tactical mission switch and a mine counter measures (MCM) switch. Alternatively, these signals may be obtained from a digital data bus in certain newer aircraft.
As previously discussed, the warning system according to the invention provides two different insufficient terrain clearance warnings according to two different warning criteria depending upon whether the landing gear of the aircraft is up or down. In the illustrated embodiment, the warning criteria for the gear up configuration are defined by a gear up warning comparator 16, while the criteria for generating the warning in a gear down configuration are defined by a gear down comparator 1 8. Both of the comparators 1 6 and 1 8 receive signals representative of the altitude above ground of the aircraft from the radio altimeter 1 2 and a signal representative of the airspeed of the aircraft from the airspeed signal source 14, and generate a warning initiation signal when the reiationship between altitude above ground and airspeed is such that insufficient terrain clearance exists.
In order to avoid nuisance warnings, the system according to the invention is disabled during take-off.. The disabling function is accomplished by a take-off flip-flop 20 that is set during take-off and reset during other phases of flight. The flipfflop 20 is set by an
AND gate 22 when the landing gear is down, and the aircraft is below 100 feet of radio altitude, and if either the speed of the aircraft is below 40 knots or the aircraft is below 10 feet as is indicated by signals applied to an
OR gate 24. The flip-flop 20 is reset by an
OR gate 26 once the altitude above ground of the aircraft exceeds 200 feet, or the tactical inhibit signal indicating a tactical mission is applied to the gate 26. The various signals representative of various airspeeds and altitudes are provided by an airspeed comparator 28 and an altitude comparator 30.The airspeed comparator 28 receives signals from the airspeed signal source 14, and compares the airspeed signal with a reference signal representative of a predetermined airspeed, such as, for example, 40 knots, and provides a signal to the gate 24 whenever the airspeed is greater than 40 knots. Similarly, the altitude comparator 30 compares the altitude signals received from the radio altimeter 12 with various internally (or externally) generated reference signals representative of various altitudes, and provides various output signals representative of whether the altitude is above or below the various reference altitudes. For example, the altitude comparator 30 provides output signals representative of when the aircraft is below 10 feet, above 10 feet, below 100 feet and above 200 feet of radio altitude to various gates in the logic circuitry.
The system is inhibited by the master inhibit signal which inhibits a pair of gates 30 and 32 in the event of a faulty instrument. In addition, the gates 32 and 34 are inhibited during tactical operations by the tactical inhibit signal, and when the aircraft is below 10 feet of radio altitude by the absence of the greater than 10 foot enabling signal. The gate 32 is enabled by a gear up signal when the aircraft landing gear is up in order to put the system under the control of the gear up comparator 16. The AND gate 34 is enabled
by the gear down signal to place the system under the control of the gear down warning comparator 18 when the gear is down. In addition, the gate 32 is inhibited by an OR gate 36 under various flight conditions, including mine counter measures and tactical maneuvers, and if the pilot desires to cancel the gear up warning.The inhibiting function is provided by the mine counter measures (MCM) inhibit signal, the gear up cancel signal and the tactical inhibit signal.
When the aircraft is flying with its gear up and it is not in a take-off mode, and the other enabling conditions have been met, the AND gate 32 is under the control of the gear up warning comparator 1 6 which generates the warning initiation signal and applies it via the gate 32 to a first voice generator 38 and an
AND gate 40 whenever the criteria indicating insufficient terrain clearance are exceeded. As long as the airspeed of the aircraft is below a predetermined airspeed, for example, 1 20 knots, the AND gate 40 is inhibited, thus preventing the warning initiation signal from being applied to a second warning generator 42.The first warning generator 38 is responsive to the warning initiation signal received from the AND gate 32 and generates a voice signal, such as, for example, "TOO LOW
GEAR", and applies it to a transducer 44 which may be a loudspeaker, an earphone or the like to provide a voice warning to the pilot. Although FIG. 1 shows the signal from the generator 38 being applied directly to the transducer 44, the signal may also be applied indirectly, for example, via the aircraft intercom system.
When the airspeed of the aircraft exceeds a predetermined airspeed, such as, for example, 1 20 knots, indicating that the aircraft is in a cruise rather than in a landing mode of operation, the AND gate 40 is enabled by the greater than 1 20 knot signal. This permits the warning initiation signal from the AND gate 32 to be applied to the TOO LOW TERRAIN warning generator 42 to cause the "TOO
LOW TERRAIN" warning to be generated and applied to the transducer 44. The generator 42 also inhibits the generator 38 when the
"TOO LOW TERRAIN" warning is being generated to avoid confusing the pilot. Thus, when the speed of the aircraft is below 1 20 knots, indicative of a landing, any warning generated will be "TOO LOW GEAR". At an airspeed above 1 20 knots, which is indicative of a cruise mode of operation, any warning generated will be ' "TOO LOW TERRAIN".
When the landing gear is down, the AND gate 32 is inhibited, and the AND gate 34 is enabled to thereby place the TOO LOW TER
RAIN warning generator 42 under the control of the gear down warning comparator 18 via the AND gate 34. Consequently, the warning criteria will be determined by the gear down warning comparator 18, and any warning generated will be "TOO LOW TERRAIN".
In the illustrated embodiment, the gear up warning comparator 1 6 and the gear down warning comparator 1 8 have been shown as two separate comparators; however, both functions can be implemented in a signal comparator whose warning criteria are modified depending on whether the gear is up or down. Similarly, the TOO LOW GEAR warning generator 38 and the TOO LOW TERRAIN warning generator 42 are shown as two separate warning generators, but a single warning generator capable of generating two distinct warnings can also be used.
The relationships between radio altitude and airspeed required to generate a warning are illustrated by the shaded areas of FIG. 2.
Below an airspeed of approximately 1 50 knots, the "TOO LOW GEAR" warning is generated, and above approximately 1 20 knots airspeed the "TOO LOW TERRAIN" warning is generated. Below approximately 40 knots of airspeed, the "TOO LOW GEAR" warning is generated when the altitude above ground of the aircraft drops below approximately 1 50 feet. The altitude required to generate the warning drops linearly with airspeed above approximately 40 knots until an airspeed of approximately 1 20 knots is reached, at which point the "TOO LOW
GEAR" warning is generated at an altitude of approximately 75 feet above the ground.The reason for the particular shape of the curve is to maximize the warning time when the pilot is actually landing, and to minimize nuisance warnings when low level maneuvers are being performed, since such maneuvers are generally performed at airspeeds in excess of approximately 40 knots. Above an airspeed of approximately 1 20 knots the "TOO LOW
TERRAIN" warning is generated whenever the radio altitude drops below approximately 75 feet regardless of airspeed. provided that the airspeed exceeds approximately 1 20 knots.
The relationship between radio altitude and airspeed required to generate a warning in the gear down mode of operation is shown by the shaded portion of the graph of FIG. 3. Because the gear is down already, no "TOO
LOW GEAR" warning is generated, and the only warning generated is "TOO LOW TER
RAIN". Above an airspeed of approximately 1 20 knots, dropping below a radio altitude of approximately 100 feet will cause the warning to be generated. This altitude is somewhat higher than the altitude required to generate the warning in the gear up case, because helicopters generally have their landing gear down when performing low level maneuvers.
Below approximately 1 20 knots airspeed, the altitude at which the warning is generated decreases linearly until the warning altitude is reduced to 10 feet at an airspeed of 58 knots.
Below an airspeed of 58 knots, no warning is given in order to permit nuisance warning free, low speed, low level maneuvering. Also, the warnings are inhibited below 10 feet of radio altitude for both the gear up and the gear down modes of operation in order to avoid nuisance warnings caused by erratic radio altitude signals at low altitudes.
Claims (11)
1. A ground proximity warning system for alerting the pilot of a rotary wing aircraft of insufficient terrain clearance, comprising;
means for receiving a signal representative of the airspeed of the aircraft;
means for receiving a signal representative of the altitude above ground of the aircraft; and
means responsive to said airspeed signal and altitude above ground signal receiving means for generating a warning if the altitude above ground of the aircraft is insufficient for the airspeed at which the aircraft is flying, wherein said warning generating means includes means for providing said warning at first altitude at a first airspeed, and for providing said warning at a second lower altitude at a higher airspeed.
2. A warning system as recited in claim 1 wherein said warning means includes means for providing a first warning if the aircraft is flying below a predetermined airspeed, and a second distinct warning if the aircraft is flying above said predetermined airspeed.
3. A warning system as recited in claim 1 wherein said warning providing means includes means for providing said warning at an altitude of approximately 1 50 feet above the ground if the airspeed of the aircraft is below approximately 40 knots, and for generating said warning at an altitude of approximately 75 feet when the airspeed of the aircraft is greater than approximately 1 20 knots.
4. A warning system as recited in claim 3 wherein the altitude required to generate a warning decreases linearly between an airspeed of approximately 40 knots and an airspeed of approximately 1 20 knots.
5. A warning system as recited in claim 4 wherein said system includes means for preventing the generation of a warning at altitudes below approximately 10 feet above the ground.
6. A warning system as recited in claim 4 wherein said warning generating means includes means for generating a first warning when the aircraft is flying at airspeeds below approximately 1 20 knots and for generating a second distinct warning when the aircraft is flying at airspeeds above approximately 1 20 knots.
7. A warning system as recited in claim 1 further including means for preventing the generation of a warning when the aircraft is taking off.
8. A warning system as recited in claim 1 wherein said aircraft has landing gear that is movable between an up position and a down position, and wherein said system includes means for receiving a signal representative of the position of the landing gear of the aircraft, and wherein said warning generating means is responsive to the landing gear position signal providing means for altering the altitudes at which the warning is generated so that the altitude above ground at which the warning is generated increases with airspeed.
9. A ground proximity warning system for alerting the pilot of a rotary wing aircraft of insuffficient terrain clearance, comprising:
means for receiving a signal representative of the airspeed of the aircraft;
means for receiving a signal representative of the altitude above ground of the aircraft; and
means responsive to said airspeed and altitude signal providing means for generating a warning if the altitude above ground of the aircraft is insuffficient for the airspeed at which the aircraft is flying, said warning providing means including means for providing a warning if the altitude above ground of the aircraft drops below approximately 100 feet and the airspeed of the aircraft is in excess of approximately 1 20 knots.
10. A warning system as recited in claim 9 wherein said warning generating means includes means for decreasing the altitude at which the warning is generated as the airspeed of the aircraft decreases.
11. A warning system as recited in claim 10 wherein said warning generating means includes means for generating said warning at an altitude of approximately 10 feet when the airspeed of the aircraft is approximately 48 knots.
1 2. A warning system as recited in claim 11 wherein said generating means includes means for linearly increasing the altitude at which the warning generated as a function of airspeed between an airspeed of approximately 48 knots and an airspeed of approximately 1 20 knots.
1 3. A ground proximity warning system for alerting the pilot of a rotary wing aircraft of insufficient terrain clearance, substantially as described herein with reference to the drawings.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US50321683A | 1983-06-10 | 1983-06-10 |
Publications (3)
Publication Number | Publication Date |
---|---|
GB8412991D0 GB8412991D0 (en) | 1984-06-27 |
GB2141683A true GB2141683A (en) | 1985-01-03 |
GB2141683B GB2141683B (en) | 1986-10-15 |
Family
ID=24001189
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB08412991A Expired GB2141683B (en) | 1983-06-10 | 1984-05-21 | Warning system for tactical rotary wing aircraft |
Country Status (14)
Country | Link |
---|---|
JP (1) | JPS608196A (en) |
AU (1) | AU548266B2 (en) |
BE (1) | BE899876A (en) |
CA (1) | CA1240771A (en) |
CH (1) | CH660159A5 (en) |
DE (1) | DE3421517A1 (en) |
FI (1) | FI841931A (en) |
FR (1) | FR2553507B1 (en) |
GB (1) | GB2141683B (en) |
GR (1) | GR81645B (en) |
IT (1) | IT1179182B (en) |
NL (1) | NL8401856A (en) |
NZ (1) | NZ207888A (en) |
SE (1) | SE8403093L (en) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1479120A (en) * | 1974-11-01 | 1977-07-06 | Sundstrand Data Control | Aircraft ground proximity warming system |
GB1535488A (en) * | 1976-07-19 | 1978-12-13 | Sundstrand Data Control | Terrain clearance warning system for aircraft |
GB2133366A (en) * | 1982-12-10 | 1984-07-25 | Sundstrand Data Control | Position-responsive ground proximity warning system for aircraft |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
IL48315A (en) * | 1975-03-18 | 1978-08-31 | United Technologies Corp | Warning system for helicopters for avoiding tail contact during landing |
JPS53114981A (en) * | 1977-03-17 | 1978-10-06 | Santo Tekkosho Kk | Continuous fabric conveying apparatus |
-
1984
- 1984-04-06 CA CA000451452A patent/CA1240771A/en not_active Expired
- 1984-04-18 NZ NZ207888A patent/NZ207888A/en unknown
- 1984-05-14 FI FI841931A patent/FI841931A/en not_active Application Discontinuation
- 1984-05-14 FR FR8407408A patent/FR2553507B1/en not_active Expired
- 1984-05-21 GB GB08412991A patent/GB2141683B/en not_active Expired
- 1984-05-30 AU AU28842/84A patent/AU548266B2/en not_active Ceased
- 1984-06-06 CH CH2762/84A patent/CH660159A5/en not_active IP Right Cessation
- 1984-06-07 IT IT48342/84A patent/IT1179182B/en active
- 1984-06-07 GR GR74951A patent/GR81645B/el unknown
- 1984-06-08 SE SE8403093A patent/SE8403093L/en not_active Application Discontinuation
- 1984-06-08 DE DE3421517A patent/DE3421517A1/en not_active Ceased
- 1984-06-08 JP JP59116819A patent/JPS608196A/en active Pending
- 1984-06-08 BE BE0/213110A patent/BE899876A/en not_active IP Right Cessation
- 1984-06-12 NL NL8401856A patent/NL8401856A/en not_active Application Discontinuation
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1479120A (en) * | 1974-11-01 | 1977-07-06 | Sundstrand Data Control | Aircraft ground proximity warming system |
GB1535488A (en) * | 1976-07-19 | 1978-12-13 | Sundstrand Data Control | Terrain clearance warning system for aircraft |
GB2133366A (en) * | 1982-12-10 | 1984-07-25 | Sundstrand Data Control | Position-responsive ground proximity warning system for aircraft |
Also Published As
Publication number | Publication date |
---|---|
CA1240771A (en) | 1988-08-16 |
GB8412991D0 (en) | 1984-06-27 |
FI841931A (en) | 1984-12-11 |
AU2884284A (en) | 1984-12-13 |
NZ207888A (en) | 1987-11-27 |
SE8403093L (en) | 1984-12-11 |
CH660159A5 (en) | 1987-03-31 |
FR2553507B1 (en) | 1988-11-10 |
SE8403093D0 (en) | 1984-06-08 |
IT1179182B (en) | 1987-09-16 |
JPS608196A (en) | 1985-01-17 |
GR81645B (en) | 1984-12-11 |
NL8401856A (en) | 1985-01-02 |
FR2553507A1 (en) | 1985-04-19 |
GB2141683B (en) | 1986-10-15 |
DE3421517A1 (en) | 1984-12-13 |
FI841931A0 (en) | 1984-05-14 |
IT8448342A0 (en) | 1984-06-07 |
BE899876A (en) | 1984-12-10 |
AU548266B2 (en) | 1985-12-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4980684A (en) | Warning system for tactical rotary wing aircraft | |
US5666110A (en) | Helicopter enhanced descent after take-off warning for GPWS | |
US4551723A (en) | Excessive descent rate warning system for rotary wing aircraft | |
CA1157132A (en) | Negative climb after take-off warning system with configuration warning means | |
US4987413A (en) | Aircraft terrain warning system with configuration modified warning and improved mode switching | |
US5187478A (en) | Configuration responsive descent rate warning system for aircraft | |
GB1535488A (en) | Terrain clearance warning system for aircraft | |
US5038141A (en) | Configuration responsive descent rate warning system for aircraft | |
US4792799A (en) | Aircraft terrain closure warning system with descent rate based envelope modification | |
US4818992A (en) | Excessive altitude loss after take-off warning system for rotary wing aircraft | |
US4639730A (en) | Excessive terrain closure warning system | |
GB2139588A (en) | System for alerting a pilot of a dangerous flight profile during low level maneuvering | |
US4916447A (en) | Warning system for aircraft landing with landing gear up | |
GB1219307A (en) | Automatic aircraft cabin pressure control system | |
GB2174665A (en) | Warning system for tactical aircraft | |
GB2141683A (en) | Warning system for tactical rotary wing aircraft | |
AU567260B2 (en) | Excessive descent rate warning system for tactical aircraft | |
GB2140757A (en) | Excessive descent rate warning system for tactical aircraft |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
732 | Registration of transactions, instruments or events in the register (sect. 32/1977) | ||
732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19960521 |