NKP S2 From United States of America, joined Dec 1999, 1714 posts, RR: 5 Reply 1, posted (12 years 10 months 2 weeks 1 day 5 hours ago) and read 1253 times:
It's really the angle of attack vane. It just says "critical airflow sensor" on a stencil near it to warn people not to touch or damage it. It is basically a potentiometer that has a vane that moves as the aircraft's angle of attack changes...the vane stays paralell to the relative forward motion of the airplane...and so as the plane's pitch changes, the vane and potentiometer tells the Air Data computers this info.--- It is primarily used for stall protection. If the vane moves past a certain point the flight crew will get a "stall warning" warning...accompanied by an intentionally irritating buzzer, and the "stick shakers" vibrate the control columns as an added warning. --- The stencil is there because it's VERY sensitive and is easily damaged by jetways, ham-fisted ground personnel etc. It is also electrically heated to prevent it from icing up and if you touch it it will burn your hand so fast that it'll kill the nerves on your fingertips....You'll smell your skin burn before you feel the pain--Trust me
NKP S2 From United States of America, joined Dec 1999, 1714 posts, RR: 5 Reply 2, posted (12 years 10 months 2 weeks 1 day 5 hours ago) and read 1248 times:
It should be noted that there are two AOA vanes...one for the pilot, the other for the co-pilot. There are also several Pitot tubes in the area: They're primarily for measuring airspeed, although some have a static orifice as well.