30 July 2003 – Flight 820

 

Research Flight from GXY

 

Pilot: Tom Root

 

T.O. 20:58 UT

 

T.D. 21:45 UT

 

By early afternoon storms had moved off the Foothills. The original target was northeast of GXY. It was declining when the aircraft arrived, but there were other vigorous cells developing in the vicinity. Several passes were made through several cells. Hail to dime size and larger was encountered, with vigorous updrafts. The mission was terminated following an generator failure at 21:31.

 

Unfortunately, neither pitot heater was turned on, so there were problems with any instrument or calculation needing a true airspeed, such as the hydrometeor imaging probes, and the updraft calculation.  Despite the airspeed problems, the 2D-C, HVPS, and hail spectrometer probes recorded reasonably good images. The peak DMT cloud water concentration calculation according to our standard calculation based on the recorded airspeed approached 4 g m-3, but the calculation needs to be redone assuming a more reasonable airspeed.  Hail concentrations from the 1-D portion of the hail spectrometer data also need to be re-done. Both the Humphrey and Crossbow accelerometers did not record good data, including the pitch and roll from the Humphrey, so the Kopp updraft calculation cannot be done. The Cooper updraft calculation gives less stable but at least qualitatively correct results.