ReportTechnical analysis of hijacker's possible landing envelope and search priorities9 January 1972page 1 of 2
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Part 93, page 40

Document date 9 January 1972

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FBI 164-81, Vault Part 93 p. 40, Report, dated 9 Jan 1972 — cooper.theunsolved.net/parts/Cooper-Part-93/pages/40

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The attached plot indicates the envelope of possible landing points of the high jacker (HJ). It is based on the following:

-- Aircraft position from USAF radar data from McChord AFB furnished by [REDACTED]

-- Probable jump time (0411 GMT) from an analysis of the recorded communication from the flight relative to the cabin pressure fluctuation. Flight tests conducted on January 6 confirmed that the pressure fluctuation almost certainly occurred at the time the HJ left the airplane.

-- Wind information from 10,000' MSL to the ground as determined by [REDACTED]

-- Human body trajectories from data furnished by The Boeing Company (free-fall) and [REDACTED] who is an expert para- chutist.

-- Time correlation from the above USAF radar information and from the NWA communications network tape recording.

-- Airplane airspeed and altitude from the airplane's flight recorder.

The plot is explained as follows:

1. The heavy dashed line C--D--E--S defines the airplane's probable ground track.

2. Line G--I--J--K defines the westernmost, and Line L--M--N--O the easternmost probable airplane ground tracks based on the stated position tolerance of ±.5 nautical mile of the USAF radar plot.

3. Lines A--B, H--P, and O--R are the average wind vectors between 10,000' MSL and the ground, and are the lines parallel to which the HJ would drift after the parachute had opened.

4. Line H--S--T defines the northernmost (earliest) points over which the HJ probably left the airplane. Line K--F--O defines the southernmost (latest) points over which the HJ probably left the airplane. The north--south span of possible jump positions is a product of the radar position tolerance of ±.5 mile, and the possible communication time determination tolerance of ±1 minute.

5. The area within the boundary defined by Points H--P--Q--R--O--K--J--I--H marks the extreme limits of probable landing points based on the above tolerances. That is, assuming the highest probable degree of inaccuracy in aircraft position, jump time, wind vector, etc., all probable HJ landing points would lie within the area defined by this line.

6. If it is assumed aircraft position, jump time, wind vector, and other inputs used are all accurate (without allowance for the above stated tolerances):

a. The HJ's landing point would be at Point A if his 'chute did not open, or if he opened it so soon that the high speed/caused 'chute damage that resulted in the equivalent of a free--fall to the ground. (The horizontal body trajectory due to