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Windshear Detection
Shear winds result from vertical winds and rapidly changing horizontal winds. The windshear system is part of the FGCS and EGPWS. The EGPWS provides detection, and the FGCS provides guidance. If the EGPWS or the radar altimeter is unavailable, windshear detection is not available.
Active between 10' and 1,500' RA during takeoff, go around, and final approach.
| Alert | Type of windshear | Aural |
| Caution | increasing headwind, up drafts | "Caution, windshear" |
| Warning | decreasing headwind (or increasing tailwind), down drafts | "Windshear, windshear, windshear" |
Windshear escape guidance mode
WSHR is a vertical mode of the FD. It is engaged by either
- Manually by pressing TOGA while windshear is detected
- Automatically in takeoff or go around modes with windshear
- Automatically when TLA >70° with windshear.
| Logic | Function |
| Gamma | allows speed build up during increasing performance windshear in anticipation of decreasing performance windshear |
| Alpha | speed maintained when approaching stall conditions |
| Speed Target | speed is managed to prevent overspeed |