2 ms·

the stall warning system uses a completely different set of sensors (they measure the airflow over the wings, looking for signs consistent with a stall) AFAIK

• lucasjung 15y ago
  Interesting. AoA probes are one way to provide stall warning, but I wasn't aware that's what Airbus used on the A-330. They also have other uses. There are also other ways to provide stall warning such as directly sampling flow over the wings (as I mentioned previously). Most light props actually use a very crude version of this. For example, the stall warning on the Cessna I flew my first few hours in was a horn on the lower part of the leading edge. In an impending stall scenario, the pressure over that part of the wing would go negative, sucking air out through the horn and causing it to sound. AoA vanes actually do work on different principles than pitot probes. The newer, fancy-schmancy ones use a whole bunch of tiny ports, each measuring pressure at different angles, and a computer interprets the results to give AoA. On older planes (including the one I have the most experience in), it's literally a vane, as in "weather vane:" it rotates into the direction of the relative airflow, so whatever angle it is at relative to horizontal is the AoA. Even if the AoA system did work on the same principle, the more important point is that it's a separate system, meaning that a failure in the pitot-static system would not cause a failure in the stall warning system. EDIT: from the picture you linked, the AoA vanes on an A-330 are of the type I'm more accustomed to: literal vanes that rotate into the airflow.