Interestingly, if taken to the extreme, the probeless AoA system actually starts to behave like a wind-shear alerter and any downdraft that is sufficient to cause excessive pitch vs flight path angle will generate an alert – it’s effectively a sink rate alert at that point. As the pilot actions are identical for both scenarios, it can be argued that the source of unexpected altitude loss (downdraft or a wing losing lift) is irrelevant.
If a down-draft of this magnitude is experienced, the pilot action is to add power Similarly, if AoA exceeds the configured limit, the pilot action is also to add power. In effect, this makes the AoA thresholds more sensitive and an alert will be generated earlier than normal – but that’s a good thing in this scenario. As the algorithm utilized compares the aircraft pitch to the actual flight path through the air, this will result in an artificial positive AoA (see diagram).Ī downdraft that forces a sink rate of -1000 FPM will effectively increase the current AoA by approximately 5.6 degrees (this is speed dependent). In this environment, the aircraft will sink at a rate that is not consistent with the aircraft pitch. However, during conditions where the aircraft is moving through a mass of air that has a vertical component, the behavior is slightly different.Īs vertical updrafts are rarely of concern, the scenario to look at is the downdraft during final approach. During the majority of flight conditions, they are equivalent. Reference Sperry Patent #3,948,096 for additional implementation details. Connection to the aircraft’s pitot static system is required.
Therefore, no dedicated AoA probe is required – only internal inertial and pressure sensors (8 in total).
#Stec 50 autopilot pitch problems full
However, if the flight path angle through the air is only 7 degrees, then the equivalent AoA is positive 3 degrees as the wing is no longer able to maintain full lift. The resulting angle is then augmented with G-Load, as determined by internal acceleration sensors.įor example, during a climb, if the pitch angle is 10 degrees up, and the aircraft’s flight path through the air (forward airspeed and vertical speed) is also 10 degrees up, the equivalent AoA is 0 Degrees. Pitch is determined by a precision internal AHRS, and flight path angle is determined by a precision ADC (airspeed and vertical speed). This is equivalent to the angle at which the wing is intercepting the body of air surrounding the aircraft – exactly the same as a probe based AoA system.
The AV-30 does not currently support vertical navigation display, but this feature will be introduced with the APA-10 autopilot interface box.Īngle of attack is determined by comparing aircraft pitch to the actual flight path angle through the air. When operating as an attitude indicator, it can drive the direction tape and provides a bearing-to indicator. This data can be overlayed in the textual fields as desired and is used to create the compass rose (GPS Track), moving map display (ARC Mode), and create the GPS HSI presentation when the AV-30 is operating as a DG instrument. The data provided includes current waypoint ID, distance to destination, ground speed, cross-track error, desired track, and bearing to waypoint. When connected to an external GPS navigator or hand-held, AV-30 operates as a repeater display. NMEA protocol supports baud rate speed of 48, while “Aviation/moving map” protocol is fixed at a 9600 baud rate. NMEA is also supported, which is output by most hand-held GPS units. This data is broadcast by the GPS navigator and no data is sent from the AV-30 back to the GPS unit. The AV-30 provides an RS-232 receive line for “aviation” or “moving map” output provided by virtually every panel mount GPS navigator in service.