Abstract: A flameless and smokeless marker attracts attention to a site. A battery and electronics section has a battery module and electronics module. The battery module connects power to the electronics module for creating responsive power-activation signals. An inflatable bag section is connected to the battery and electronics section and has an inflator and flexible bag. The flexible bag is metalized to reflect radar signals and has ChLCD strips receiving the power-activation signals to be visible to radiation from a remotely located search beacon. A beacon section connected to the battery and electronics section and inflatable bag section has IR laser diode arrays arranged in a circular pattern and a strobe light. The IR laser diode arrays and strobe light are coupled to receive the power-activation signals from the battery and electronics section to emit IR radiation and visible radiation, respectively.

Abstract: An apparatus, method and computer program product for displaying terrain and terrain alerts to pilots of rotary wing aircraft provides a terrain display consistent with the performance capabilities of such aircraft.

Abstract: A method for flying in a degraded visual environment comprising the steps of collecting environmental data, processing the data and fusing the data together into a combined input output. The output is fed into a head down display, head mounted or heads up display and, preferably to a fly-by-wire vertical take-off and landing capable vehicle wherein the fly-by-wire system makes automatic adjustments to the helicopter.

Abstract: A method, apparatus and computer program product for alerting the pilot of a helicopter of a possible tail strike hazard.

Abstract: A tactical surveillance sensor projectile system includes a propellant and primer chamber, a firing device, a sensor device, a signal processor, and a fiber optic cable; the firing device fires the primer and propellant to establish a powered phase of flight followed by a ballistic phase of flight to clear an obstacle; the sensor device generates surveillance signals representative of ambient characteristics beyond the obstacle at least during the ballistic phase of flight; the signal processor is responsive to the sensor device for converting the signals representative of ambient conditions to an optical data stream; and the fiber optic cable delivers the optical data stream to a ground station at least during the ballistic phase of flight.

Abstract: The present invention relates to a warning device for indicating dangerous circumstances, especially for helicopters, having a signal receiving means for receiving and processing an operational status signal; a signal comparison means which compares the received operational status signal against predefined criterion; a monitoring signal generating means which generates a monitoring signal when the operational status signal meets said criterion; a monitoring transmission signal transmitting means which wirelessly emits said generated monitoring signal; a monitoring transmission signal receiving means which receives said emitted monitoring signal; a monitoring transmission signal comparison means which analyzes whether said received monitoring transmission signal meets predefined monitoring transmission signal criteria; and an output means which emits an output signal when the monitoring transmission signal meets said criteria, whereby said receiving means, said monitoring transmission signal comparison means a

Abstract: Provided is a modified configuration that permits operation of instrumentation onboard platforms that may experience severe environmental conditions. The instrumentation permits autonomous acquisition of performance data. Acquired data may be recorded for later playback as well as provided to the platform's operator in real time in multiple formats, such as warning lights, digital displays, video, or audio. An application would be for sensor systems used on an automobile to record performance data, providing a warning when routine maintenance is due or a catastrophic failure is imminent. A specific application uses a flight-certified missile launcher pod on an F/A-18 aircraft, as incorporated in the aircraft's wingtip and modified to hold instrumentation conforming, at least in part, to the launcher pod's internal dimensions.

Abstract: An apparatus, method and computer program product has a first terrain awareness mode and a second terrain awareness mode selectable by the pilot.

Abstract: Process and device for reducing the spectral line noise inside an aircraft, especially a rotating-wing aircraft, in particular a helicopter. Said device (1) comprises sensors (Ca, Cb) for measuring the values of vibratory and/or acoustic parameters, controllable mechanical elements (A) forming secondary sources of noise, and a main computer (CAL) determining, on the basis of the values measured by the sensors (Ca, Cb), control commands for the mechanical elements (A), as well as at least one reference sensor (CO) for measuring a reference parameter which is correlated with the noise, and possibly an auxiliary computer (4) for calculating, on the basis of the values measured by the reference sensor (CO), a reference signal, and said main computer (CAL) determines the control commands by carrying out filtering with respect to the reference signal.

Abstract: An apparatus and method for tracking aircraft wingtip position during taxi operations to prevent collisions with nearby obstructions. A patterned illumination source is attached proximal the wingtips to project a readily discernable target pattern in the direction of taxi travel. At least a portion of the target pattern is reflected off of any obstructions that lie in the straight-line direction of travel, such that the pilot can maneuver to avoid striking the obstruction. By way of example, the patterned illumination source comprises a laser module positioned with the navigation and/or strobe light of the aircraft that is configured to project a circular pattern in front of the wingtip. The device may be retrofitted to existing aircraft without additional wiring with the control of activation being selectable via power cycling of existing aircraft lighting controls.

Abstract: An apparatus, method and computer program product for suppressing an alert generated by a terrain awareness system rotary wing aircraft of potentially hazardous proximity to terrain also reduces nuisance warnings and provides a terrain display consistent with the unique performance capabilities of such aircraft.

Abstract: A system for monitoring the operation of an aircraft, especially a helicopter, includes data acquisition and processing components and display components which are able to display at least one indicator for at least one parameter relating to the operation of the aircraft. The system furthermore includes selection components which allow an operator to select at least one option for a specific configuration of the system, and components able to automatically configure, during the selection of at least one option, at least the data acquisition, processing and display components so as to adapt them to the selected option.

Abstract: A portable emergency lighting device for helicopters which transmits visible and radio signals which indicate the position of an emergency rescue area. The device has a housing with a beacon disposed on its top wall. The device also includes a battery source disposed in the housing that is rechargeable via a special adapter by an emergency vehicle using a standard 12 volt DC system. The device is easily carried to a remote location where vehicles may be unable to reach. Several lighting devices can be configured to define a landing area near the location of a patient for easy access and rescue. The device may be mounted and transported within a variety of different emergency rescue vehicles.

Abstract: A system and method for evaluating flexible structures such as textiles under load generally. A specific embodiment is shown for parachutes. A plurality of first sensors and second sensors are attached to the parachute on its canopy and suspension lines. Preferred first sensors are fiber Bragg gratings (FBG) type sensors, and preferred second sensors are modal power distribution (MPD) type sensors. A fiber optic network interconnects the pluralities of first and second sensors to provide sensor outputs which are converted to electronic signals, modulated and transmitted to a receiving station for receiving and processing the transmitted modulated electronic signals. The preferred fiber optic network includes a plurality of light emitting diodes positioned at one end of each fibers and a photodiode array positioned to receive light from each of the fibers.

Abstract: A flap angle measurement system is disclosed for a helicopter rotor blade. The blade includes a trailing edge and a flap hinged to at least a portion of the trailing edge about a pivot axis. The flap angle measurement system includes a Hall effect sensor mounted to the trailing edge of the rotor blade. The Hall effect sensor has a sensing face. A magnet is mounted to the flap at a location spaced apart from the pivot axis. The magnet has a pole axis that is located parallel to the sensing face of the Hall effect sensor. A power source supplies power to the Hall effect sensor. A controller receives output signals from the Hall effect sensor which are indicative of the location of the magnet with respect to the sensing face of the Hall effect sensor. The position of the flap relative to the trailing edge is determined based on the received signals from the Hall effect sensor. In one embodiment of the invention, there is a second Hall effect sensor mounted on the other end of the flap.

Abstract: The present invention provides ground proximity warning system and method for aircraft, particularly rotary wing aircraft such as helicopters. The warning system generally includes an air ground detection device disposed on the aircraft to confirm whether the aircraft is on the ground or in the air. A controller is coupled to the air ground detection device and configured to move between a ground state when the aircraft is on the ground and an airborne state when the aircraft is in the air. The controller may be used for a variety of applications within the aircraft, such as disabling a ground proximity warning device when the aircraft is on the ground and enabling the warning device when the aircraft is in the air. In addition, the air ground controller may be used to signal the beginning and the end of a flight for the aircraft's flight history fault memory.

Abstract: The present invention relates to a device for aiding the piloting of an aircraft, especially a rotary-wing aircraft, in particular a helicopter. According to the invention, said device (1) comprises first means (2) for determining, on the one hand, the slope and the heading of a preset path of the aircraft and, on the other hand, the slope and the heading of a flight path which the aircraft can take in order to join up with the preset path, and second means (3) for presenting, on a display screen (5), simultaneously a first characteristic sign (S1), whose position on the display screen (5) is representative of the slope and of the heading of the preset path and a second characteristic sign (S2), whose position on the display screen (5) is representative of the slope and of the heading of the flight path.

Abstract: The present invention relates to a method and a device (1) for assistance with the maintenance of an aircraft, especially of a helicopter, intended for replaying maintenance information. According to the invention, data relating to the operation of the said aircraft are recorded, with a view to their being replayed in the form of maintenance information, these data being accessible to a monitoring and visual display system (2) of the said aircraft, and only data capable of being visually displayed by the said monitoring and visual display system (2) are recorded with a view to presenting them to at least one pilot of the said aircraft.

Abstract: A portable lighting instrument having a light emitting diode assembly capable of being applied to a lighting system for a helicopter taking off and landing place. The system is constituted by a lighting instrument including a heliport lighthouse installed in a fixed position temporarily determined as a temporary taking off and landing place for a helicopter, a wind lamp, a landing area lighting lamp, a boundary guide lamp, and a boundary lamp. For at least the boundary guide lamp and the boundary lamp out of these lighting instruments, the portable lighting instrument according to the present invention can be used. The lighting instrument comprises a casing; a solar cell disposed on the outer surface of the casing; an electrical double-layer capacitor placed in the casing and charged by the solar cell; and a light emitting diode assembly disposed on the top of the casing and lighted by a current supplied from the electrical double-layer capacitor.

Abstract: A device and method that allows a pilot to switch between communication and navigation inputs without disrupting the pilot's current task. An audio selector panel has inputs for at least two communication transceivers and outputs for at least a pilot's headset. A rotary switch on the face of the audio selector panel selects which inputs are connected to which outputs. The audio selector panel further includes a remote swap switch that is mounted in a position in which the pilot can activate the switch without removing his/her hands from a yoke or diverting his/her eyes to the switch. The activation of the remote swap switch causes the audio selector panel to switch between the communication and navigation inputs. In this way, the pilot can switch communication and navigation inputs without disrupting the current task of the pilot.

Abstract: Aircraft tail strike protection is provided by displaying to a pilot tail strike warning symbols during takeoff and approach to landing. In a takeoff scenario, a pitch margin indicator symbol referenced to a boresight symbol provides a pilot with anticipatory information and an awareness of the pitch attitude margin before a tail strike incident. In an approach to landing scenario, a TAILSTRIKE warning annunciation is referenced to a flight path symbol and alerts the pilot of an impending tail strike incident. The symbols displayed during either scenario center on the pilot area of focus for each task. They give the pilot an awareness of an impending tail strike incident and necessary reaction time to avoid it.

Abstract: Taxi and slope landing symbology for a helicopter having a main rotor drive shaft and a main rotor hub defining a hub moment, wherein the main rotor drive shaft and the main rotor hub have hub moment limits. The taxi and slope landing symbology comprises a first symbol for providing a symbolic representation of the hub moment limits, and a second symbol for providing a dynamic symbolic representation of the hub moment, wherein the second symbol is disposed in combination with the first symbol to provide a visual cue of the hub moment relative to the hub moment limits.

Abstract: An autonomous helicopter blade end lighting device including a light source being connectable to a helicopter blade end, and a power source being connectable to the helicopter blade end for providing the light source with power for operation.

Abstract: The present invention provides ground proximity warning system and method for aircraft, particularly rotary wing aircraft such as helicopters. The warning system generally includes an air ground detection device disposed on the aircraft to confirm whether the aircraft is on the ground or in the air. A controller is coupled to the air ground detection device and configured to move between a ground state when the aircraft is on the ground and an airborne state when the aircraft is in the air. The controller may be used for a variety of applications within the aircraft, such as disabling a ground proximity warning device when the aircraft is on the ground and enabling the warning device when the aircraft is in the air. In addition, the air ground controller may be used to signal the beginning and the end of a flight for the aircraft's flight history fault memory.

Abstract: A camera assembly 10 images a distant landscape and a downward landscape every a predetermined period of time. A position recognizing unit 30 of a moving object (autonomous running vehicle) detects the movement of the moving object on the basis of the movement between the imaged pictures of the distant and downward landscapes, which are imaged at different imaging times. That is, the movements of the distant-view and down-view images are converted to the moving amounts in the actual space on the basis of the distance images thereof, respectively, and the component of rotational speed based on the movement of the distant-view image is removed from the component of velocity based on the movement of the down-view image to derive a pure component of translation speed.

Abstract: An airborne power line detector and warning system includes a low frequency radio and antenna for detecting an AC signal of about 50 to 60 hertz. The system also includes a subsystem for producing a unique audio signal such as a series of clicks for warning a pilot that he is flying close to one or more power lines. In addition, the system includes a mute feature for muting the audio signal and replacing it with a visual signal. Finally, the system includes a gain sensor for replacing the audio signal at any time that the helicopter reduces its distance to a power line. An airborne power line detection and warning system which includes a second system or back up system is also disclosed. That system includes a GPS receiver and GIS data base to position a helicopter with respect to a power line grid and sound an alarm when the helicopter approaches a power line.

Abstract: A pilot warning system is disclosed for a helicopter having a main rotor rotatable about a yaw axis, a fuselage connected to the main rotor and having a tail boom with a controllable force mechanism to counter-act the torque exerted on the fuselage by rotation of the main rotor. The pilot warning system acts on foot pedals operatively connected to the controllable force mechanism, with the pedal movement controlling the amount of force exerted by the controllable force mechanism on the tail boom to the control the orientation of the helicopter fuselage about the yaw axis. A position sensing device senses the location of at least one of the foot pedals between its first and second positions, and a warning indicator operatively connected to the position sensing device provides a warning to the pilot when the sensed foot pedal reaches a predetermined distance from one of the first and second positions.

Abstract: A two-stage alarm for a rotary wing aircraft, such as a helicopter which operates on a collective control arm. A moveable mass or weight is operatively connected to the collective control arm. The moveable weight may be of a reciprocating type or a rotor driven mass which is mounted eccentrically for rotation about an axs which is spaced from the center of gravity of the weight. In the latter case, a D.C. motor spins the weight rapidly about the axis at a first speed to produce a shaking action to the collective control arm as a warning of an approaching danger. The weight is moved more rapidly to produce a much more noticeable action at a second frequency, or at an increased amplitude as a warning of a more imminent or serious condition which requires immediate action.

Abstract: A flight control indicator for twin-engine aircraft, in particular a rotary-wing aircraft comprising two turboengines for driving at least one rotor, intended to provide the power margin available on the engines of the aircraft as a function of the flight conditions. Display means (6) presents a single dial (8) furnished with two needles (9.sub.1, 9.sub.2), each of them corresponding to a respective engine, and positioned in such a way that, when the engines are operating normally, the two needles are merged.

Abstract: A device and method that allows a pilot to switch between communication and navigation inputs without disrupting the pilot's current task. An audio selector panel has inputs for at least two communication transceivers and outputs for at least a pilot's headset. A rotary switch on the face of the audio selector panel selects which inputs are connected to which outputs. The audio selector panel further includes a remote swap switch that is mounted in a position in which the pilot can activate the switch without removing his/her hands from a yoke or diverting his/her eyes to the switch. The activation of the remote swap switch causes the audio selector panel to switch between the communication and navigation inputs. In this way, the pilot can switch communication and navigation inputs without disrupting the current task of the pilot.

Abstract: The invention is an electronic system for warning helicopter pilots of the presence of electric power lines during landing. The system detects electromagnetic fields created by electricity flowing through the power lines. When the helicopter is closer than a predetermined distance from the power line, visual and audio alarms alert the pilot of the danger. When the helicopter is a safe distance from the power line, the alarms reset.

Abstract: A wing tip system for rotor craft includes a downwardly-facing light housing to provide a visual aid to rotor wingtip position. This system is visible to crew members and to adjacent crew, particularly when using night vision goggles (NVG) or other ambient night vision (ANVIS) equipment. This allows tip lighting to be provided in situations where covert helicopter operations are desired. The lighting further is compatible with ANVIS equipment, in that it permits operation noncandescent light in order to prevent blooming or other effects which would otherwise diminish the effectiveness of the ANVIS equipment. The lighting system further has a higher level of illumination, in which rotor tip lighting is increased to become more visible without the use of ANVIS equipment.

Abstract: The present invention provides ground proximity warning system and method for aircraft, particularly rotary wing aircraft such as helicopters. The warning system generally includes a barometric altitude rate detector, such an altimeter and a rate circuit, disposed to detect the rate of change of the barometric altitude of the aircraft. A controller is coupled to the detector for receiving the barometric altitude rate signals and adjusting the signals based on the ground effect from the main rotors when the aircraft is near the ground. Typically, the controller decreases the barometric altitude rate signals to compensate for the apparent increase in barometric altitude rate caused by ground effects. This reduces the number of nuisance warnings that may otherwise occur during takeoffs, landings or other low altitude flight conditions.

Abstract: A device and process are disclosed for indicating clearance requirements of an aircraft maneuvering on a surface such as an apron, taxiway or flight deck. The device has an electromagnetic generation mechanism for generating a high intensity, low diffusing electromagnetic beam, and a projecting mechanism for securing the electromagnetic generation mechanism to the aircraft and projecting the beam toward a projection region. The projection region extends axially and in alignment with the distal end, and from the surface upward. In one embodiment, the electromagnetic generation mechanism is a laser that outputs a laser beam in the visible light spectrum. The beam produces an image upon the surface within the projection region, or upon an obstacle in the aircraft's path. Thus, the pilot can ascertain the clearance requirements by observing the projected images on the runway surface.

Abstract: An improved system is provided suitable for use in landing an aircraft (for example, helicopter, RPV, VTOL) on shipboard comprising a support, base, platform or housing, reciprocal from remote a landing area on the deck of a ship to a position proximate the landing area, the housing carrying an upwardly directed light sensor comprising a lens system and a pair of band-pass filters, one filter before the lens system of the sensor and one after the lens system, the filters each passing the identical wavelength of light at its center but which each need not have the same band width as the other, a pulse detector in close proximity to the upwardly directed light sensor, and means for securing the aircraft to the support, housing, base or platform.

Abstract: A ground proximity warning system (GPWS) for a rotary-wing aircraft provides a warning of excessive barometric altitude loss as a function of the product of time and the terrain clearance. The warning system is only enabled during a take-off mode of flight and is disabled during other modes of flight. The mode warning logic monitors the speed of the aircraft, the terrain clearance of the aircraft as well as the position of the landing gear to enable the altitude loss warning logic. When the barometric altitude loss as a function of the time product of the terrain clearance exceeds a predetermined value, the mode switching logic switches to an approach mode of flight to disable the excessive altitude loss warning system to minimize nuisance warnings during various maneuvers including ship-to-ship and oil platform-to-oil platform flight maneuvers.

Abstract: A system for sensing objects in the flight path of an aircraft and alerting the pilot to their presence includes a laser radar subsystem for emitting a beam of laser energy, receiving returns from objects, and processing the returns to produce range data related to the range of the objects from the aircraft. A scanning subsystem scans the beam and produces directional information related to the instantaneous direction of the beam relative to the aircraft. Processor circuitry controls operation, processes the range data and directional information with instrumentation data from the avionics system, produces video information related to the range, direction, and type of the objects, and interfaces the video information to the video display system.

Abstract: A system for illuminating parts of an aircraft, such as a helicopter, including three low-intensity position lights (10) mounted on the aircraft, with two of the position lights mounted in a forward location and spaced laterally from the center of the aircraft and a third position light mounted in an aft location centrally positioned on the aircraft. The three position lights provide a triangular light formation that indicates the position of the aircraft during tactical, covert operations. The position lights include a chemiluminescent light source (12) and a housing (22) for carrying the chemiluminescent light source. Each housing is secured to a part of the aircraft by means of a bracket (52) and a pair of band clamps (60). The chemiluminescent light source is visible from within the housing within a limited range of the aircraft. Preferably, the chemiluminescent light source creates an infrared light that is detectable by means of night vision goggles worn by pilots of nearby flying aircraft.

Abstract: Aircraft systems and sensors are monitored by pre-wiring a plurality of mating connectors to each system. Each mating connector has a positive voltage pin, a zero voltage pin and a reference pin. For those systems and sensors that emit zero voltage, the system is connected to the positive voltage pin while a jumper is used to connect the zero voltage pin to the reference voltage pin. For those systems emitting positive voltage, the system is connected with the zero voltage pin while a jumper is used to connect the positive voltage pin to the reference voltage pin. For each system or sensor monitored, there is a voltage comparator having both a positive and a negative input connected with a rear-mounted connector for connection with the pre-wired mating connectors. The rear-mounted connectors have identical pin arrangements with the mating connector for proper connections.

Abstract: A system for illuminating parts of an aircraft, such as a helicopter, including three low-intensity position lights (10) mounted on the aircraft, with two of the position lights mounted in a forward location and spaced laterally from the center of the aircraft and a third position light mounted in an aft location centrally positioned on the aircraft. The three position lights provide a triangular light formation that indicates the position of the aircraft during tactical, covert operations. The position lights include a chemiluminescent light source (12) and a housing (22) for carrying the chemiluminescent light source. Each housing is secured to a part of the aircraft by means of a bracket (52) and a pair of band clamps (60). The chemiluminescent light source is visible from within the housing within a limited range of the aircraft. Preferably, the chemiluminescent light source creates an infrared light that is detectable by means of night vision goggles worn by pilots of nearby flying aircraft.

Abstract: A helicopter hazardous ground object warning system has a horizontally rotating beam from a laser rangefinder which detects and measures the distance to ground objects which may present a hazard to a helicopter during hover, takeoff and landing. The rotating laser beam from the rangefinder is positioned on the fuselage of a helicopter to create a quasi-horizontal (planar) scan pattern parallel to the earth's surface. The maximum and minimum ranges which can be measured by the rangefinder to objects and to ground personnel are preset. The minimum range can be used for blanking range measurements as a function of angle from helicopter parts, such as landing skids or wheel structures. A pilot warning system for hazardous objects may include an audible or visual alarm which may include a screen positioning all objects relative to the helicopter rotors and an external audible personnel warning system alerting ground personnel in the hazardous zone.

Abstract: A telemeter is used to measure the distances between a sequence of points on a target surface. The telemeter includes an emitting source provided with a pulsed laser sending out a pencil of light energy in a determined direction of sight, a contra-rotating wedge communicating, to the pencil, a deflection along an epicycloidal type of scanning pattern in a plane perpendicular to the axis of sight, and a receiver including the same contra-rotating wedge and a photodiode. The disclosed device can be applied more particularly to a system for the detection of obstacles of a wire-shaped type.

Abstract: A pattern of light is projected from multiple sources located on an aircraft to form two clusters. The pattern of each cluster changes as the aircraft flies above and below a predetermined nominal altitude. The initial patterns are two horizontal, spaced apart lines. Each is capable of changing to a delta formation as either the altitude or the terrain varies. The direction of the delta cues the pilot as to the direction of corrective action.

Abstract: An electrical sensing circuit has a sensor device and an indicator such as a warning light. The system of the present invention continuously monitors the operational status of the sensing circuit. Normally open sensors are provided with a resistance across the open circuit contacts to provide a small leakage current. For each sensor, high and low comparators are provided. The high comparator is ground seeking and is used to detect closure of open circuit sensors, grounded connections and systems tests. The low comparator detects open circuits or high resistances such as might be caused by broken or loose wires, improperly connected sensors or electrically degrated sensors. The comparators drive logic components, which in turn drive indicators of circuit operational readiness.

Abstract: A weight measurement system calculates the gross vehicle weight of a helicopter while in hover or level unaccelerated forward flight by measuring and averaging the distances 20,22 between the fuselage 24 and the underside of each main rotor blade 26 at the front and rear of the fuselage 24, measuring the main rotor speed, and correcting for the effects of vertical and horizontal drag forces on the fuselage due to the spinning rotor and forward velocity, respectively, using predetermined vehicle calibration data. An inhibit signal 54 may also be provided to the weight calculation logic to disable the weight calculation when the vehicle is in a flight regime not suitable for accurate weight measurement.

Abstract: The invention is a helicopter blade crack detection system for blades that are hollow and pressurized or evacuated to a low pressure A rotating assembly having a rotating indicator assembly photo-optically communicates to an airframe detection assembly providing high reliability, ease of maintenance, and EMI secured.

Abstract: A power management symbology (PMS) display system for helicopters that provides a continually updated, combined analog/digital symbolic display of selected status information vis-a-vis the helicopter powerplant. The PMS display system includes a multi-dimensional, continuously updated, combined analog/digital display symbol that is optimized for discriminability and compatibility with respect to the pilot's visual system.

Abstract: An improved system is provided suitable for use in landing an aircraft (for example, helicopter, RPV, VTOL) on shipboard comprising a support, base, platform or housing, reciprocal from remote a landing area on the deck of a ship to a position proximate the landing area, the housing carrying an upwardly directed light sensor comprising a lens system and a pair of band-pass filters, one filter before the lens system of the sensor and one after the lens system, the filters each passing the identical wavelength of light at its center but which each need not have the same band width as the other, a pulse detector in close proximity to the upwardly directed light sensor, and means for securing the aircraft to the support, housing, base or platform.

Abstract: The aircraft (1) incorporates means for emitting a conical light beam (14). The vessel (2) incorporates photosensitive cells (6) materializing the outline of the beam on the vessel, which is an ellipse (7). Means determine the equation of the ellipse (17) and, from this, landing data which are displayed on a panel (25).

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.