AERIAL ICE OBSERVATION 



Seventy-six ice observation flights were made in three PB1G 

 (B-17) type aircraft by the United States Coast Guard Air 

 Detachment at Argentia during the ice season. These flights 

 averaged 918 miles in length and 6.4 hours long. The longest 

 fiight was 1275 miles in length. 



The primary objective of the aerial ice observation was to 

 guard the southeastern, southern and southwestern limits of the 

 ice encumbered area in the vicinity of the Grand Banks so that 

 shipping might be advised of the extent of that dangerous area. 

 In addition, the aerial ice observation had the purpose of main- 

 taining, insofar as visibility conditions and aircraft availability 

 permitted, a detailed, up-to-date picture of the ice situation in the 

 Grand Banks region for the benefit of mariners traversing the 

 ice area. Ice reports from shipping were of invaluable assistance 

 in attaining these objectives. 



The ice observation flight plans were usually made up of a sys- 

 tem of parallel lines spaced at 20 or 25 mile intervals depending 

 on conditions of visibility. Loran was the primary method of air 

 navigation. A trained aerial ice observer was assigned to each 

 ice observation flight. Radar aided the observer in locating ice, 

 especially where visibility conditions were not good. 



As in past years, the prevalence of fog in the Grand Banks area 

 hampered the effectiveness and the systematic scheduling of ice 

 observation flights. Weather reports from shipping and weather 

 forecasts made by the United States Fleet Weather Central at 

 Argentia were very helpful in avoiding the scheduling of flights 

 during periods of low visibility in the search areas. 



Flight statistics for the season are presented in the following 

 table : 



TABLE I 



Aerial Ice Observation Statistics for the 1956 Ice Season 



1 Days on which possible to search visually at least 50 percent of scouting area with 25 mile spacing between legs of 

 flight plan. 



2 Ratio (xlOO) of area actually searched visually to area planned to be searched. 



