Abstract: An improved instrument for measuring low indicated air speed greatly reduces variation with one or more of time, temperature, and ambient pressure change. This is accomplished by periodically re-zeroing the transducer using only a single electronically controlled valve. Re-zeroing may be initiated in response to a change in the internal temperature of the transducer.

Abstract: Instruments and methods are disclosed which measure absolute energy and irradiance of UV light sources. The response curves of exemplary optical stacks of the radiometry instruments are substantially rectangular with steep transitions at the cutoff frequencies. Angle of incidence (AOI) control in combination with one or more interference filters in the optical stack enable the full optical stack to produce repeatable and accurate measurements. Inverse response filters are disclosed for leveling optical stack response.

Abstract: A warning system alerts a helicopter pilot that a low-G condition is imminent or occurring. The low-G alert employs an accelerometer to detect a vertical acceleration of the aircraft. Higher frequency vibrations in the output of the accelerometer are removed by a filter to provide a clean signal representing vertical acceleration of the aircraft. This signal is processed by a central processing unit (CPU) to perform a threshold detector function. The CPU is configured to detect the possibility of the onset or occurrence of a low-G event. Upon detection, the CPU triggers an audible alert to announce “Low-G. Pull aft.” or the like until the low-G event has been corrected or avoided.