AERIAL ICE OBSERVATION 



In 1953, two PBlG (B-17) aircraft assigned to the United States 

 Coast Guard Air Detachment, Argentia, Newfoundland, performed 

 the ice observation flights, supplemented by PBY's when advan- 

 tageous. The persistence of bergs in potentially dangerous positions 

 and along the east coast of Avalon Peninsula throughout the season 

 requhed frequent ice observation flights. 



A qualified ice observer was assigned to each ice observation flight. 

 The ice patrol aircraft were equipped with two automatic-trackmg 

 loran receivers, and a continuous watch was maintained on both 

 receivers during flights to insure precise navigation. The flights were 

 ordinarily planned a day in advance, and were laid out usually with 

 legs 25 miles apart. The scouting interval was increased or decreased 

 as° necessary to fit special situations, mainly the changing visibility 



conditions. 



There was a total of 45 ice observation flights made on 38 different 

 days. On 7 occasions, 2 flights were flown the same day. Of the 45 

 flights, 13 had a visual effectiveness of 50 percent or less. The visual 

 effectiveness of a flight is the ratio of the area actually visuaUy searched 

 to the araa planned to be searched, usually on the basis of 12^ miles 

 visibility. The actual effectiveness of a flight may be much greater 

 than the visual effectiveness by means of a concurrent radar search 

 and diverting from the planned track to attempt identification of 

 radar targets. It is considered that there were 32 days out of a possible 

 88, from 6 March to 1 June mclusive, with satisfactory weather for 

 observation in flight areas. 



On a monthly basis, there were 13 good observation days m March 

 from the sixth to the end of the month, 9 in Aprfl, and 8 in May. 

 June is not included due to the termination of aerial ice observation 

 on the sLxth of that month. Ten of the eleven flights in March had 

 a visual eft'ectiveness greater than 50 percent. In Aprfl and May, 9 

 of 13 and 10 of 17 flights respectively had a visual effectiveness greater 

 than 50 percent. March was the best month for flight observation, 

 and as the percentage of fog over the Grand Banks graduaUy increased 

 during the season, Aprfl and May were progressively worse flight 

 months. For a closer study of flight statistics, see table 3 below. 



Tabic 3 -AERIAL OBSERVATION FLIGHTS AND WEATHER DURING THE 



1954 ICE SEASON 



Month 



March (6-31) 



April 



May 



June (1-6)-- 

 Totall953.- 



Satisractory 

 flight 

 days 



Number 



of 



flights 



Actual 



flight 

 days 



Flights 50 



percent 



visual 



effect or 



less 



Average 

 visual 

 effect 



Percent 

 85 

 64 

 61 

 72 

 71 



Miles 

 flown 



12, 130 

 13,460 

 16, 200 

 5,270 

 47, 060 



