4 ms·
The reading from the pitot tubes (pressure sensors) for a particular airspeed varies with the sensors angle to the airstream so the airspeed value is adjusted b
by daddylonglegs 8y ago
The reading from the pitot tubes (pressure sensors) for a particular airspeed varies with the sensors angle to the airstream so the airspeed value is adjusted based on the angle of attack (AoA). If the AoA sensor is on the fritz on one side the airspeed reading for that side changes.
For redundancy, each pilot receives separate instrument readings from independent sensors. When the airspeed readings disagree a warning is activated and the pilots are expected to follow a prescribed and memorized procedure. The warning that the AoA sensors disagree was a paid option before this crash and the Lion Air crash.
- mannykannot 8y agoWhile the changes in the right pressure altitude indicator track those of the radar altimeter reading, the left falls below it -- except, in the last 15 seconds, there are blips where the left pressure altitude jumps to match the right one. These correspond to the the times when the errant left AofA indication briefly matches that from the (apparently working) right AofA vane. The airspeed discrepancy has the same pattern: the left is reading low and also showing blips, where it equals the right reading, that also correspond to when the AofA indicators match. All this would be consistent with the left AofA reading being used to correct the left static pressure reading by raising it at high angles of attack, and vice-versa for the right AofA vane and static port (this assumes there is a right static port used by the right pressure-driven instruments, an a left port for the left ones.)