Detecting Clouds Associated with Jet Engine Ice Crystal Icing.

Over 150 jet engine power-loss and damage events have been attributed to a phenomenon known as Ice Crystal Icing (ICI) during the past two decades. Attributed to ingestion of large numbers of small ice particles into the engine core, typically these events have occurred at high altitudes near large convective systems in tropical air masses. In recent years there have been substantial international efforts by scientists, engineers, aviation regulators and airlines to better understand the relevant meteorological processes, solve critical engineering questions, develop new certification standards, and devise mitigation strategies for the aviation industry.

Lightning initiation: Strong pulses of VHF radiation accompany preliminary breakdown.

We analyze lightning initiation process using magnetic field waveforms of preliminary breakdown (PB) pulses observed at time scales of a few tens of microseconds by a broad-band receiver. We compare these pulses with sources of narrow-band very high frequency (VHF) radiation at 60-66 MHz recorded by two separate Lightning Mapping Arrays (LMAs). We find that almost none of the observed PB pulses correspond to geo-located VHF radiation sources, in agreement with previous results and with the hypothesis that processes generating VHF radiation and PB pulses are only weakly related.