Off-the-shelf altitude and cabin pressure alerter

Citation

(2001), "Off-the-shelf altitude and cabin pressure alerter", Aircraft Engineering and Aerospace Technology, Vol. 73 No. 5. https://doi.org/10.1108/aeat.2001.12773ead.008

Off-the-shelf altitude and cabin pressure alerter

Off-the-shelf altitude and cabin pressure alerterKeywords: Innovative Solutions & Support, Pressure sensors

To give pilots early warning of potentially dangerous cabin altitude and pressure conditions, Innovative Solutions & Support, the Pennsylvania-based supplier of cockpit data systems, reports that it has developed a dedicated solution – an off-the-shelf altitude alerter that is stated to be fully RVSM compliant and has already been field proven on all aircraft that require cabin pressurization (Plate 6). RTCA certifications include DO-160D (environment) and DO-178B Level D (software).

The unit issues three different types of warnings when sensed cabin altitude is at or above 10,000ft (3,000m). It flashes cabin altitude on its liquid crystal display (LCD), it annunciates a caution light located within its integral pushbutton, and it triggers audio alerts in the form of a warning message within the pilots' headsets as well as a Sonalert horn. Cabin altitude continues to flash until the altitude alerter's pushbutton is pressed or until sensed cabin altitude reaches 9,500ft (2,800m).

Plate 6 Innovative Solutions & Support's altitude alerter

The altitude alerter function has four user-selectable operating modes and inputs and displays the selected "go to" target altitude during altitude capture operation. The modes are: altitude alert, which annunciates conditions of approach to and departure from a user-selected altitude; minimum descent altitude (MDA), which indicates approach to a user-selected minimum altitude; static air temperature (SAT), which displays SAT; and cabin altitude, which indicates cabin pressure by displaying its equivalent altitude. Baro-corrected altitude and SAT data are supplied from the plane's digital air data computer (DADC) via ARINC 429. It computes cabin altitude (cabin pressure) using an integral pressure transducer. Altitude data are displayed in feet or meters, as directed by cockpit altimeter via an RS232 link.

The unit's pushbutton has multiple functions. It selects operating mode, cancels alert and fault indications, activates the indicator self-test and, with the target altitude adjust knob, selects audio alert type and adjusts volume. The target altitude adjust knob is also used for setting the alert altitude/MDA mode target altitudes and the altitude capture mode selected "go-to" altitude, which is displayed in the upper portion of the LCD. The SAT and cabin altitude are displayed in the lower portion of the LCD.

Further details are available from Innovative Solutions & Support. Tel +1 610 889-9898; Fax: +1 610 296 3024; Web site: www.innovative-ss.com