Hurricane Emily

Operational Synoptic Flow Experiment
(930827I Aircraft 43RF)

Scientific Crew

Chief Scientist -- J. Franklin

Doppler Scientist -- F. Marks

Dropwindsonde Scientist -- R. Burpee

Workstation -- J. Griffin

This document is divided into 3 sections (Each section is written by the Chief Scientist):

Mission Briefing

Vortex interaction as in the OPS Plan, 43RF high, 42RF low (8000'), recover in Bermuda. 42RF and 43RF ferry to MIA to pick up the HRD crew and expendables, then conduct full endurance mission in Emily. Aircraft take off from MIA as close to 1800 Z as po ssible. AF reconnaissance aircraft will arrive on station at ~2330 Z at 5000'. 43RF will coordinate drops with the AF aircraft and 42RF. 42RF is requested to pick up a 2100Z fix for NHC.

Mission Synopsis

42RF and 43RF arrived in MIA at 1600Z, we briefed at Signature and then took off late-1845-1850Z. Almost immediately 42RF had problems with the TA radar and 42RF had problems with the ODW system, before reaching storm. Repairs were made and we pushed on . Started pattern at 2126Z, 43RF 160 nm W of center and 42RF moving to a position 40 nm N of center (radars working at the time). At 2136Z the ODW system crashed with the first sonde in the air, requiring an 18 min restart time. At 2147Z 42RF started in bound from 40 nm N of center and 43RF was inbound from 50 nm W of center on first coordinated Doppler fig. 4. 42RF TA radar went out shortly there after never to come back up for any extended period until the ferry back to Bermuda. Both aircraft continu ed with planned pattern hoping the ODWs and 42s TA radar would be repaired.

Excellent radar presentation from 43RF for radar composites and Doppler radar mapping (EVTD). Both drops in the inner core failed or were missed because of problems. Drop 50 nm S of center was marginal, as was the one at 100 nm. 42RF kept to their patt ern still hoping for the radar to be repaired. On the leg to point 6, 160 nm SSW of the center James became concerned that we had compromised the experiment because of the sonde failures in consecutive outer legs. 42RF decided to try and orbit outside t he storm to repair the radar. Decision was made that if the radar wasn't working and the ODWs any better by the next time of a coordinated fig 4 we would abort the mission. 43RF completed first LF composite and sent it via ASDL. The buffer had to be cl eared somewhat to get it out, but it went.

No joy on 42RF TA radar, and despite marginal ODW 160 nm SE of center we decided to end pattern after one more pass through the center for LF composite and EVTD purposes. At 0009 started last run across the eye, 43RF 50 nm SE of center, 42RF 40 nm NE of center. 0020 we hit eye roughly together and both exit out to NW to have 43RF Doppler over C-SCAT swath. Past info to AF aircraft just arriving on station, 42RF last fix was 0017Z: 26 38"N, 65 23"W-982mb extrapolated from 8000'. Sent second LF composi te on ferry back to Bermuda. Landed in Bermuda at 0136Z.

Mission Evaluation and Problems

We cut our losses after 1/3 of the pattern was completed (point 9) and returned to Bermuda because of numerous ODW failures and the TA radar problem on 42RF. Jimmy Franlin deemed it unnecessary to continue pattern with so many failed drops already. 42R F radar problems cinched the decision. Better to cut our losses and regroup for the next day. Part of the ODW problem may have been operator error. James and Al Goldstein will try to work out a solution to improve ODW performance on the next mission. 4 2RF radar problems are more of a mystery. The radar started working fine on ferry to Bermuda. Jim Roles thinks it was a radar control unit (RCU) card.

We did have some successes. 43RF transmitted two LF radar composites via ASDL and managed to run VTD on 3 legs with very good success. Not our best performance, but not too bad considering the circumstances - (1) new pattern, (2) first mission of the sea son, and (3) attempting to do a mission during a deployment ferry. We will evaluate our problems and improve (I hope).


  1. 42RF never had a working TA radar. No data in the storm. Jim Roles thinks it was a radar control unit (RCU) card.

  2. 43RF had numerous ODW failures, compromising the flight. Dropped 7 sondes and 5 were failures. Combination of operator error and equipment malfunctions. ODW station is cramped and the position of the line printer is awkward to see (need flashligh t). Also felt James should be in the ODW seat because he can then better interact with ODW operator.

  3. Some initial ASDL glitches caused the buffers to back up forcing 43RF to request some of 42RFs ASDL buffer slots to clear our buffer. ASDL computer had initial problems talking to HRD workstation which were repaired followed by similar problem with AOC main system. Apparent that 30s data rate for ASDL coupled with radar images and ODW messages push the ASDL communication system near its max capacity and any little glitch can cause it to real gum up the works.

  4. We had some problems with the pickup in MIA that will also need to be evaluated. We need to improve briefing. Brief should start with important details for pilots and Navs, then leave them to file flight plans, while scientists and flight director s deal with mission specifics and data requirements. We delayed filing time, and subsequent departure time because the brief was too detailed for everyone. Also, someone on 42RF shut down the INE, which caused a long delay on takeoff.