Old thread but... might this help? http://forum.kerbalspaceprogram.com/threads/64227-1-0-2-Smart-Parts-v1-6-5-Proximity-Sensor-Bug-Fixes-May-17 Altimeter ------------------- Capable of detecting when the craft hits a specified altitude, and if it's ascending, descending, or either, and then firing an action group or staging. Useful for auto-jettisoning fairings on ascent, or activating parachutes on landing.