Table D-3. HU-25 Deployment Data. 



Date 



Deployment # 



Position 



A/C Speed Drop Altitude 



Jan 21 '88 



Jan 21 '88 



Jan 21 "88 



42-57 N 

 69-51 W 



43-00.2 N 

 69-34.6 W 



43-12.4 N 

 69-32.5 W 



140 Knots 



140 Knots 



140 Knots 



8000 feet 

 (level flight) 



5000 feet 

 (level flight) 



8000 feet 

 (right turn) 



Three AXBT's were successfully 

 deployed on 21 January (Table D- 

 3). All three AXBT's transmitted 

 for a period of time equivalent to a 

 complete 300 meter drop. All 

 three AXBT's were deployed in 

 waters less than 300 meters, and 

 the temperature probe again 

 simply measured the bottom 

 temperature for the remainder of 

 the 3.3 minute drop time. How- 

 ever, the goal of the test was to 

 determine the ability to receive 

 data on the airdrop, not to meas- 

 ure the temperature. 



Operational Use of AXBT's 

 during the 1988 IIP Season 



Based on the results of the testing, 

 the International Ice Patrol pur- 

 chased and assembled its own 

 AXBT system. It consisted of 

 three single frequency VHP wide 

 band receivers, a Sippican MK-9 

 Digital Data Interface with the RF 

 demodulator board for AXBT 

 operations, audio cassette record- 

 ers, and an HP-85 desktop 

 computer. The AXBT data would 

 be recorded on audio cassettes on 

 the aircraft for later playback and 

 analysis on the ground. 



Twelve AXBT's (Table D-4) were 

 deployed from IIP HC-130's in 

 May and June 1988 on the Grand 

 Banks of Newfoundland during ice 

 reconnaissance flights. After each 

 flight, the audio recording of each 

 AXBT drop was played back 

 through the MK-9 and processed 

 using the I-1P-85 computer. 

 Sippican's AXBT computer 

 program was again used to 

 process the data. After process- 

 ing, the digital AXBT data were 

 recorded on magnetic tape. From 

 the digital recording, a series of 

 expanded temperature plots were 

 obtained. IIP personnel manually 

 determined the significant (inflec- 

 tion) points from the AXBT paper 

 trace. Again, it took about 30 



minutes to playback, process, and 

 analyze each AXBT. The signifi- 

 cant point analysis was finally 

 telecopied from Newfoundland to 

 the IIP Operations Center in 

 Groton, Connecticut, where a 

 JJXX Bathythermograph message 

 was prepared and transmitted to 

 the Meteorological and Oceano- 

 graphic Center (METOC) in 

 Halifax, Canada; the Naval 

 Eastern Oceanographic Center 

 (NEOC) in Norfolk, Virginia; and 

 the Fleet Numerical Oceanogra- 

 phy Center (FNOC) in Monterey, 

 California. Figure D-3 is a graphic 

 depiction of the data flow. 



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