Mission Summary
20020903H Aircraft 42RF
Two plane CBLAST mission into Tropical Storm Edouard

Scientific Crew (42RF)

Lead Scientist	Paul Chang (NESDIS)
GPS Dropsonde	Stan Goldenberg
HRD Workstation	Peter Dodge
Near real-time data	L. Connor(NESDIS)
IWRAP/USFMR	A.Zhang/D. Esteban (NESDIS)

Mission Briefing:

This mission was designed to collect data for the NESDIS ocean winds and rain experiment, collect data for CBLAST objectives, test/practice coordination between planes for future CBLAST missions, and test coordination for the high density 12 dropsonde experiment through the eyewall.

Mission Synopsis

A pre-briefing was held with AOC flight directors before the flight planning brief with the pilots and navigators to clarify the CBLAST and ocean winds hurricane flight patterns. Two hours prior to the flight, a second briefing with the flight crew was held to discuss the flight profile.

The scheduled 1700 UTC takeoff of N42 was delayed a little over 30 minutes due to problems loading the AXBTs. The decision was made to launch them from the inside since the planned flight altitudes were less than 10,000ft. The mission was into Tropical Storm Eduoard located off the East coast of Florida. The first part of the mission was a figure four pattern through the center with N42 (high plane 7,000ft) following N43 (low plane 1,000 and 5,000ft).

A 12 gps dropsonde drop was coordinated between the two planes as we flew through into the convective region of Eduoard during the figure four pattern. This portion of the mission was meant as a practice exercise for deployment through an actual hurricane eyewall. N42 dropped the first 8 sondes while N43 dropped the 4 remaining sondes. There were a few issues with the dropsonde tube on N42 that required using the freefall chute, but otherwise the drops went reasonably well. There was room for improvement of between plane communications on when N42 finished the last drop and when N43 should commence dropping.

After completion of the figure four pattern, N43 commenced a low altitude stepped decent for CBLAST with N42 flying a high altitude crosswind and along wind leg with drops before departing to find convection. N42 flew several racetrack legs across bands of varying precipitation rates. Four gps dropsondes were dropped in precipitation and splash points were noted and flown back over. The maximum surface winds found were about 30 knots and precipitaiton was in the 30-40 dBZ range. IWRAP and USFMR were operating nominally and collecting data during the entire flight. Upon completion of the precipitation flight legs, N42 met up at N43 at the second planned CBLAST stepped decent pattern for a high altitude upwind and alongwind pass with drops. Upon completion of this N42 headed back to MacDill for a flight duration of 6 hours and 15 minutes.

Problems:

A problem with loading the AXBTs externally inadvertently led to complications with the gps dropsonde tube. The decision was made to launch the AXBTs from the freefall chute since we would be flying below 10,000ft and thus, avoid any further delay in departure time. The lack of cabin pressure for the freefall chute caused a dropsonde to get stuck in the tube and burn on the motor that opens and closes the chute. This net result of all this was that the freefall tube had to be used for the AXBTs and gps dropsondes, which worked just fine for this mission.

The X-band tail radar failed early in the mission. Intitial thoughts that the problem would be an easy motor swapout turned out to be incorrect, and the radar antenna system is currently out of the plan undergoing repair. Current estimates put readiness for Tuesday.

Coordination between the planes worked out great and was expertly handled by the AOC crew on both planes. However, the course corrections performed by N42 (turns and speed changes) tended to be less than ideal for the IWRAP/USFMR systems. So for future coordinated two plane missions such as this we will try work out a more amenable strategy.

Paul Chang
NESDIS
Lead Scientist

Mission Data

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