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The Altimeter-Compass Cruising Altitude Rule (ACCAR) eliminates midair collisions that are systematically encouraged by current regulations and airspace design. This 70-year-old technique was proposed in 1968 by Leighton Collins (Richard's father) in four Air Facts articles, one of which is available at
Imagine there is a compass rose sticker on your altimeter. To use ACCAR fly so that the 100-ft altimeter needle points at the altimeter compass rose direction that matches your own magnetic heading. Everybody doing this flys parallel same-direction paths at all altitudes. See example altimeter pictures at
By design, head-ons are automatically 500 ft apart. Right-angle path crossings are automatically 250 feet apart. Only overtaking collisions are allowed after a long chase up the turbulent wake of the slow pilot up front. Under FARs 91.159/179, BY DESIGN, near polar heading aircraft are at the same altitudes in head-on collision paths. For example, aircraft heading 359 and 181 degrees are required by law to be as common altitudes. See my request to the FAA to fix the problem, at
ACCAR cost virtually nothing to pilots and aircraft owners. However, the FAA has to admit that they made a technical error in regulatory design over 30 years ago. Is that cost too high for the FAA, compared to the cost for the airlines and victims of future easily avoidable midair collisions?
If you have any questions, write me by deleting the underscores and tildes out of r_p~a_t~l_o~v_a~n_y@r~o_c~k_e~t_m~a_i~l.com (confuses the spam generating bots).
Colorado Licensed Professional Engineer 29977
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