The 8:12 Arc Theory

BY ERIC ULIS

            The purpose of this theory is to ascertain the possible jump and landing spots for DB Cooper. The foundation of this theory is based upon two very reliable notions:

     1) DB Cooper jumped from the jet at 8:12 PM.

     2) The jet arrived near the Malay intersection and made a turn at 7:59 PM.

            The magnitude of the turn from this point is where things begin to get uncertain. Indeed, the real debate regarding the flight path typically starts at this juncture.

            There are three other pieces of concrete evidence that will be factored into this theory:

     1) The location of the placard find which was 46.243157 N, 122.683612 W.

     2) The location of the Tena Bar money find which was 45.718588 N, 122.759453 W.

     3) The flow of the Columbia River which is north from Tena Bar.

            The placard find will be used as a constraint given that we can determine that it likely traveled 4-8 miles to the northeast after departing the jet—this is based upon what we know factoring in wind speed (approximately 30 knots at 10,000 feet and closer to 20 knots at ground level) and wind direction (from approximately 225 degrees) on the night of the skyjacking. Furthermore, this is also based upon the approximate size and weight of the placard and an extrapolation of an analysis conducted regarding the placard's free-fall by Robert Nicholson for Tom Kaye of the Cooper Research Team and an updated analysis conducted by Nicholson at my request in 2019. Of note, it is assumed that the placard did not migrate much during the seven years it was on the ground in the woods.

            The money find will be used as a constraint inasmuch as the presumption is that Cooper either:

     1) No-pulled or lost the money upon jumping. In other words, the money arrived on Tena Bar via the Columbia River, thereby requiring it to enter the river upstream from Tena Bar.

     2) Cooper survived with the money and intentionally buried the money.

            The money find will also be used to make some reasoned assumptions if it is presumed that Cooper survived the jump and buried the money on Tena Bar. Specifically, the primary assumption will be that Cooper would have walked to Tena Bar with the money because there seems little value in burying the money if it is already secured in the trunk of his car. Moreover, the fact that Tena Bar is essentially on an island with only two ways in and out of the area in 1971 shall serve to constrain possible landing spots too. More to the point, it is unlikely that Cooper opted to swim to Tena Bar.

            To begin, when creating an arc of possible jet locations at 8:12 PM, factoring a Malay turn at 7:59 PM, we end up with an arc with a western-most point approximately 3 miles south of St. Helens, Oregon over Sauvie Island, and an eastern-most point approximately 3 miles south of LaCenter, Washington. Additionally, if the jet flew in a straight line to Vancouver it would likewise be over Ridgefield, Washington at 8:12 PM. If the jet headed directly to Tena Bar from Maylay, at 8:12 PM it would be approximately 1 mile west of Ridgefield, Washington, more than 6 miles north of Tena Bar. It is worth noting that the above figures represent the minute of 8:12 which actually covers a 60-second period of time. Furthermore, during the 8:12 minute the jet traveled approximately three miles. Therefore, the west-to-east arc which is slightly greater than 7 miles in length also has a depth of 3 miles.

            The 8:12 arc shows us that it is impossible that the jet could cross any part of the Columbia River upstream from Tena Bar by 8:12 PM. In turn, this means it is impossible that the money arrived on Tena Bar via the Columbia River or by natural means. Therefore, the only possible option is human intervention. This strongly implies Cooper survived the jump.

            Next, when we consider the location of the placard find we know that the jet had to travel at least several miles southwest of where the placard was discovered because of the southwest winds that night. This means if the jet traveled in a straight line from Maylay, through a point just shy of 4.5 miles due west of the placard find—which is an extremely conservative number borrowed from Robert Nicholson's free-fall analysis conducted for Tom Kaye as noted above—this path would eventually take the jet through a point 6 miles west of Ariel, Washington, right over the top of LaCenter, Washington and arrive at a point approximately 3 miles south of LaCenter, Washington by 8:12 PM. Given the constraint placed upon the flight path by the placard find, this would be the furthest east location that Cooper could have jumped. However, considering the location of the money find on Tena Bar, a landing in this area seems highly unlikely.

            Now, when we consider the western-most landing spot for Cooper we have a constraint in the form of the Columbia River. That is to say, Cooper had to have landed east of the Columbia River in Washington State—remember, the Columbia River flows north in this region. It is unreasonable to consider that he would have landed on the Oregon side of the river and swam across to the Washington State side ultimately ending up at Tena Bar.

            Likewise, we also have a constraint in Lake River which bounds the “island” Tena Bar is located on along the north and the east. As with the Columbia River, it is unlikely that Cooper would have landed on the other side of Lake River and opted to swim across. Nonetheless, there is one small access "S" bridge that crosses Lake River and enables access to the northern portion of the Ridgefield National Wildlife Refuge. Therefore, it is possible that Cooper landed near Ridgefield, Washington, walked west and crossed into the Ridgefield National Wildlife Refuge via this small access bridge.

            This means that Cooper would have to have landed north of Tena Bar on the “island” or just beyond Lake River with access to the river "S" bridge. That said, when we factor in the 8:12 arc of the flight path, the furthest-west point for the jet which provides a post-jump drift that gets Cooper to the Washington State side of the border is a point approximately three miles due south of St. Helens, Oregon. Additionally, we are further constrained by an eastern-most point that is likely over Lake River. The reason for this is that if Cooper jumped any further east than this point, his post-jump drift would actually carry him to the eastern portion of Ridgefield, Washington near I-5 which seems unlikely given his walking options to Tena Bar.

            Therefore, given the constraints listed above, the only place Cooper could have jumped was along a 3-mile portion of the 8:12 arc that runs west to east from 3 miles due south of St. Helens, Oregon to approximately Lake River. Furthermore, if Cooper jumped along this potion of the arc he would land in the Ridgefield National Wildlife Refuge or the western or northern portion of Ridgefield, WA. Additionally, upon leaving the area in the direction of Portland and Vancouver, Cooper would walk right past the Fazio Brother’s property and Tena Bar approximately 8 miles down Lower River Road.

            Notably, in order to get to this segment of the 8:12 arc, the path of the jet would require a turn at Maylay heading almost due south from that point or shortly thereafter. In fact, this trajectory would eventually bring the jet to the west of Portland and ultimately to the Canby intersection.

            It is also interesting to consider that if Cooper landed in the Ridgefield National Wildlife Refuge this may explain why the parachutes and attaché case have never been found. After all, a significant portion of the refuge is off-limits to people and has been for decades.