GB2452999A

GB2452999A - Audible altitude alert system

Info

Publication number: GB2452999A
Application number: GB0725370A
Authority: GB
Inventors: Nicholas Andrew Donald Gribble
Original assignee: GCAP Ltd
Current assignee: GCAP Ltd
Priority date: 2007-09-21
Filing date: 2007-12-31
Publication date: 2009-03-25
Also published as: GB0718473D0; GB0725370D0

Abstract

An altitude alerting system for aircraft, which alerts the pilot(s) with visual indications, audio tones and/or a recorded or synthesised voice when he/she approaches or deviates from a set altitude, height or flight level. Buttons may allow the setting of data; a display may show the data set; the output may be to the aircraft's intercom system; power may be internal or external.

Description

VOCAL ALTITUDE ALERTING SYSTEM -DESCRIPTION

This invention relates to an altitude alerting system for aircraft, which alerts the pilot(s) with visual indications, audio tones and/or a recorded or synthesised voice when he/she approaches or deviates from a set height, altitude, or flight level. it is designed primarily for use in the single-pilot Instrument Flight Rules environment, giving prompts at lower levels as would a second pilot in such situations, but is also useful in multi-pilot and Visual Flight Rules environments. At higher levels its main purpose is to reduce height and altitude incursions (ie accidental flight through the height, altitude or flight level assigned by Air Traffic Control).

The term aural' when used throughout this document refers to audio tones or a recorded or synthesised voice. QFE means the pressure at a specified point, normally an airfield. QNH means the equivalent pressure at mean sea level. SPS means the Standard Pressure SettIng of 1013.2mb.

The terms height, altitude and flight level refer to the elevation indicated on a barometric altimeter when QFE, 01*1 or SPS respectively are set on the altimeter subscale.

The present invention uses electronic apparatus incorporating a pressure/temperature sensor to measure the air pressure and temperature, and a microprocessor to compute these values and apply the required logic. Alternatively, or complementary to the barometric sensor, height/altitude data could be derived from satellite systems such as GPS and related to an appropriate datum pressure setting. Provided for the pilot is a small liquid crystal display (or similar) of one or more lines and an array of buttons for selection of different modes and entry of data.

Provision may be made for the unit's attachment via modification to an aircraft's static system in order to enhance accuracy, but this is not necessary for the unit to function if the pilot accepts the reduced accuracy caused by the use of cabin static pressure instead of ambient static pressure.

Pressing the buttons enables QFE, QNH or SPS to be selected as an operational mode and, in the case of QFE and QNH, for this pressure to be set as required between 900mb and 1100mb. SelectIng QFE, QNH or SPS changes the mode of the unit so that it measures and works on height, altitude or flight level respectively.

The buttons allow the pilot to set the height, altitude or flight level at which he wishes the device to give a warning. The present invention allows the set height/altitude to be varied between Oft and plus l0000ft, or between flight level 30 and flight level 100; provisIon may be made for higher or lower altitudes or flight levels if required.

Figure 1 shows the display in the present invention in the QFE mode (typical figures shown).

The system can be switched on and off or suspended using the buttons.

A visual and/or aural warning may be presented to the pilot when the device is switched on in order to state various disclaimers. The present invention requires that the user accepts this warning by a button press before the device functions.

The present invention provides a warning when the pilot approaches the desired height, altitude or flight level during a climb or descent. It gives this warning at 500ft to go, lOOft to go, and at the specified height, altitude or flight level. When the pilot has levelled at this height, altitude or flight level, the device then warns the pilot If the aIrcraft's height, altitude or flight level vary by more than lOOft from that set. These values can be varied in software, and provision may be made in the software to allow them to be changed by the pilot using the buttons.

The typical accuracy of the present invention is less than lOft (variations in cabin versus ambient static pressure notwithstanding). Using satellite information this may be reduced even further.

The present invention normally gives only an aural warning, but provision may be made for the display also to show a visual warning. As well as or instead of the visual and aural warnings, audio tones may be used. Provision may be made for the pilot to choose between different tones/voices or to record a voice for the device to play back.

Provision may be made for the device to show the aircraft's height, altitude or flight level, which would be enabled by the pilot using the buttons. This is envisaged as a backup safety feature should the aircraft's altimeter(s) or temperature gauge(s) fail.

Power for the device comes from internal or external batteries, or from an aircraft's own power supplies. Provision may be made for warning of impending power loss or low battery state.

Provision may be made for a Power-On Self Test (POST). During this test, the present invention shows the ambient pressure and temperature, which the pilot can check against known figures as displayed on other cockpit instruments in order to determine the device's accuracy and serviceability. Provision may be made during this test for the device to emit a test sound in order to adjust the volume, and to confirm connection and system operation etc. It is intended that the output from the device be audible to the pilot(s), thus it needs to be attached to the aircraft's Intercom somehow. The present invention does this using a standard aviation 6b microphone plug but provision may be made for it to be hard-wired into an aircraft intercom system. Provision may be made for impedance matching and line balancing as required. Wireless technologies may also be used for this purpose.

The device is intended to be used as a standalone device within the aircraft, although the technology could be incorporated into aircraft avionics hardware (for example GPS receivers).

Claims

The devke uses either a pressure sensor to measure air pressure and temperature, or satellite signals to measure height/altitude/flight level, or a combination of the two methods -pressure/temperature sensor and satellite signals, and uses microelectronics to compute height/altitude/flight level from this data based on an appropriate datum pressure settln& Existing devices use radio signals from a height-encoding altimeter via the aircraft's transponder this method only works when the aircraft's transponder is being Interrogated.

2 The requisite Information Is displayed on a small screen.

Buttons are provided for switching off, on or Into suspension, for the acceptance of warnings, and for the setting of data.

L4-The device uses either WE, QNH or SPS as its datum pressure setting, thus calculating and using height. altitude or flight level respectively. The pilot can set the mode as required and the pressure as dictated by Air Traffic ControL The device Is designed to measure height, altitude or flight level Existing systems either measure altitude using transponder output, or measure rate of climb or descent, sometimes coupled with engine power output, In order to provide so-called ground proximity warnlng This device differs from such systems In the way that the height/altitude/flight level Information is obtained, arid how It Is presented to the pilot.

I, Accuracy of the device Is typically less than loft Existing transponder-based systems have a maximum accuracy of lOOft since an aircraft's transponder transmits height information In lOOft Increments.

7 The desired height, altitude or flight level for the alerts can be set by the pilot.

Alerts are provided to the pilot(s) when approaching the desired height, altitude or flight level or when deviating from the same by set margins. Existing devices do not warn on deviation from the desired height/altitude/f Ught level.

Alerts are provided by recorded and/or synthesised voice alerts as well as audio tones and visual messages. Existing devices do not use vocal alerts.

Power Is provided by Internal or external battery or from an aircraft's power supply.

U Output Is provided to the aircraft's intercom system, either by hard-wiring, plug-in or wireless connection.