Date: 25 Jun 99 01:32:52 From: email@example.com (PS2727) Organization: AOL http://www.aol.com References: 1
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Airplanes with retractable gear have squat switches to avoid retraction when on the ground. If the handle is raised on the ground and the switch is in the "ground" mode, the gear will not retract. On larger planes the squat switch is used for many things. One example that comes to mind is that window and pitot heaters (and water drain masts) operate on low power when on the ground and switch to high power inflight. Each design is different but some systems need to know when the plane is on the ground. When spoilers are armed for automatic deployment they can be triggered by wheel spin-up or the squat switch, or thrust reversal.