NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Flight 19 route: wrong course
From: Paul Hirose
Date: 2009 Nov 25, 14:56 -0800
From: Paul Hirose
Date: 2009 Nov 25, 14:56 -0800
Flight 19 (of "Bermuda Triangle" fame) was supposed to fly true course 091 to begin their navigation exercise, according to many Web sites. In fact, I've never seen anything to the contrary. http://www.history.navy.mil/faqs/faq15-1.htm http://www.ibiblio.org/hyperwar/USN/rep/Flight19/ However, there's some evidence that the true courses widely quoted on the Web are wrong. See the image of a chart (said to be from the official report) on this Web page: http://www.bermuda-triangle.org/html/bad_navigation_.html Obviously, the first two legs cannot be true course 091. The angle of the blue line with respect to the nearby parallel of latitude is much greater than one degree. By opening that image in an application such as Windows Paint it's possible to read pixel coordinates of any point in the image. Then with plane trigonometry you can determine the orientation of the course lines and meridians. With respect to "image north", I calculate that the meridians are oriented to 357�, and the three sides of the route are 94�, 345�, and 238�. Therefore, with respect to the meridians, the true courses are 097, 348, and 241. Compare those figures to the conventional values widely given on the Web: 091, 346, and 241. In an earlier posting I noted that the conventional courses and distances, when plotted, fail to close on the start point. The discrepancy is 10.6 NM, or 3.4% of the total distance. But if the courses I measured on the picture are used instead, this is reduced to 2.2 NM, or .7% of the distance. That's excellent when you consider that all courses and distances were rounded to 1 degree and 1 mile. (The plot was actually done mathematically on a Mercator grid to simulate an aircraft flying rhumb lines.) The Web page with the chart has something else which tends to confirm my theory. It says the planned route went to Great Stirrup Cay. Well, with course 091 you'd miss the cay by 32 NM. But course 097 takes you within a mile at closest approach, and at my calculated turn point you're just 3 miles away. Flying my courses (but using the conventional distances), the endpoints of the legs are: N26�03.0' W080�07.0' start; depart on TC 097 N25�56.2' W079�05.3' Hen and Chickens Shoals; depart on TC 097 N25�48.0' W077�51.5' turn to TC 348 N26�59.6' W078�08.4 turn to TC 241 N26�01.2' W080�09.2' end The point I labeled "Hen and Chickens Shoals" is 4 NM from the wreck of the concrete ship Sapona, which was probably a target for Flight 19's bombing practice. (This route goes right through the present day airway intersection BAHMA, depicted on the Miami Sectional Aeronautical Chart.) All these computations are based on one small image on a Web site, so I'm not going to claim there's something wrong with the widely quoted courses. It's hard to believe that such a discrepancy could have escaped detection. But it's interesting that when the new courses are plotted, the former misclosure in the route practically disappears. Finally, none of this gets us any closer to the reason for Flight 19's disappearance. It's strictly about two possible garbles in the description of the navigation problem, as it has been passed down to us. -- -- NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To , email NavList+@fer3.com