Flight Plan and Location of Position with Respect to Ground The position of the helicopter with respect to the ground at all times will be made with the aid of aerial photographs. Prior to making the first aerial survey, the survey officer will, from a careful examination of photographs of each island, pick out and numberseveral points which can be easily located both on the photograph and on the ground. Straight lines will be drawn between these points so that each island is crossed in different directions by these lines. An illustration of a photo marked in this manner is given below. 4 Direction of Chain 2 Line 1-2 will always be the line in the direction of the chain of islands. One copy of each marked photo will be carried by the Survey Officer; a duplicate copy of each will be retained by RIC. Using the aerial photo, the survey officer will direct the pilot to fly accurately over each line at a constant speed of about 20 mphat an altitude of 25 ft when possible. The instrument man will take a series of readings at equally spaced points above each line using the procedure given below. Procedure for Taking Readings The instrument man will sit in the seat next te the door of the helicopter and will hold the T1B survey meter between his knees. The survey officer will give the instrument man prior warning of readings to be made by giving the code nameof the island, line number,and altitude. As the helicopter passes over the beginning of the line the survey officer will say “Read.” The instrument man will make the reading and report it over the interphone. Both will record the reading. The survey officer will continue to say “Read” at intervals until the end of the line is reached, each reading being recorded by both the survey officer and the instrument man. Whenthe intensity is low or is uniform over the whoie island, as is expected in most cases, the alove procedure can be simplified. The helicopter should first fly over line 1—2 of the island at a speed of about 30 mph. If the intensity is uniform along that line, only one reading need be reported by the instrument man and recorded. If there is a marked variation of intensity along the line, a series of readings should be taken along each line accordingto the procedure given above. Fov that M-day survey which will be made before conditions have become stabilized, the simplified procedure wil! be used. Only the maximum reading along line 1-2 of each island will be recorded. In both procedures correction of readings to ground intensity will be as described in Sec. C.14.5. C.14.5 Correction to Ground Intensity Measurements made of residual contamination from Greenhouse shots showthat intensities measured from an H-19 helicopter at an altitude of 25 ft vary from one-third to one- 1 were sa emmy Ae ONE 2 agen ot ne acter oe come pte ee see C.14.4 ORCIS ONCamie ot memamre enemies A deat lS WS Zire C.14.3 ee EINE a Te Ce Communications between the survey officer and the instrument man will be by the regular interphone syste:n of the helicopter. Communications with RIC will be by the established helicopter radio net. See ethte RI Hid Bh TAM EME oy, aD nere ee ee emerean le MRPOT EENOE ine weee