Warning systems for aircraft that provide a warning to the pilot of an excessive altitude loss or an excessive descent rate after take-off as long as he is flying below a predetermined altitude have the problem that they require a valid radio altitude signal for proper operation, and tend to generate nuisance warnings when used in low flying aircraft. This problem is solved by comparing the accumulated altitude loss after take-off (12, 14, 62, 34) with the product of a barometrically derived altitude and the length of time the aircraft has been flying (12, 14, 30, 32, 34). A warning is generated if the altitude loss is excessive for the accumulated time-altitude product after take-off (38, 40). Thus, the system is more sensitive immediately after take-off and becomes less sensitive as flight time is accumulated to permit low level maneuvering without generating false or nuisance warnings, and does not require a valid radio altitude signal to generate a warning.
A warning system provides a warning to the pilot of an aircraft during a take-off mode of flight of a relatively dangerous flight condition, such as improper configuration of the flaps during a take-off mode of flight prior to the aircraft becoming airborne. In order to avoid nuisance warnings, the warning system is disabled once the aircraft becomes airborne. The warning system monitors the flap position of the aircraft as well as the airspeed and provides a warning when the flaps are improperly configured during a take-off mode of flight. Different aural warnings are provided as a function of the airspeed of the aircraft.
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.
A cabin pressure altitude monitor and warning system provides a warning when a detected cabin pressure altitude has reached a predetermined level. The system is preferably embodied in a portable, pager-sized device that can be carried or worn by an individual. A microprocessor calculates the pressure altitude from signals generated by a calibrated pressure transducer and a temperature sensor that compensates for temperature variations in the signals generated by the pressure transducer. The microprocessor is programmed to generate a warning or alarm if a cabin pressure altitude exceeding a predetermined threshold is detected. Preferably, the microprocessor generates two different types of warning or alarm outputs, a first early warning or alert when a first pressure altitude is exceeded, and a second more serious alarm condition when either a second, higher pressure altitude is exceeded, or when the first pressure altitude has been exceeded for a predetermined period of time. Multiple types of alarm condition indicators are preferably provided, including visual, audible and tactile. The system is also preferably designed to detect gas concentrations and other ambient conditions, and thus incorporates other sensors, such as oxygen, relative humidity, carbon dioxide, carbon monoxide and ammonia sensors, to provide a more complete characterization and monitoring of the local environment.
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.
A ground-based CFIT warning system provides pilots with CFIT alerts. The system is based upon a ground-based tracking system, which provides surveillance of aircraft, such as the AirScene.TM. multilateration system manufactured by Rannoch Corporation of Alexandria, Va. The system monitors both horizontal and vertical positions of aircraft. When an aircraft has been determined to be operating below safe altitudes, or too close to obstructions, the pilot is provided with a warning. The warning may be delivered via the pilot's voice communications and/or a data link or the like.
