NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: course, heading, track
From: Trevor Kenchington
Date: 2002 Feb 7, 09:04 -0400
From: Trevor Kenchington
Date: 2002 Feb 7, 09:04 -0400
Paul Hirose wrote: > I think you were incorrect to contradict John LeRoy. His message was > obviously in the context of flying. Aviators (at least in the U.S.) > don't use the Bowditch meaning for some of those navigational words. Perhaps you are right and if so, I owe John an apology. I don't claim any knowledge of the navigation terminology of aviators. However, if John was seeking to draw a distinction between that and Bowditch-like terminology, his intention was not clear to me. [He wrote "course was never path through the air, for instance" in response to Nigel Gardner's "Course was path through the air or water" -- the "for instance" implying, to me, that John was suggesting that the course is not the path through either fluid medium. (Much more dissection of wording and this thread will be even further lost in the intricacies of English grammar than it is in those of navigational terms!] > In aviation, "course" means the intended direction of flight over the > ground. > A heading is always a direction measured with respect > to the longitudinal axis of the airplane, or in other words, the > direction in which the airplane is pointed > "TRACK - The actual flight path of an aircraft over the surface of the > earth." So, if I understand that correctly, U.S. aviation terminology does not distinguish between what we surface-bound types call "heading" and "course". Are aircraft so stable in yaw that the distinction is not needed? Then "course" is used in the air for what would be "track" on the water, while the aviator's "track" approximates to the surface navigator's "course made good" -- though the latter is viewed as a straight line from point to point, whereas the aviator's "track" appears from the above definition to include whatever random movements about that line the aircraft makes (small for a high-flying jet but presumably not for a low-powered light aircraft at low altitude). It must be tough for Navy aviators, navigating their aircraft by one terminology while their floating runways move about following a different one! Trevor Kenchington -- Trevor J. Kenchington PhD Gadus@iStar.ca Gadus Associates, Office(902) 889-9250 R.R.#1, Musquodoboit Harbour, Fax (902) 889-9251 Nova Scotia B0J 2L0, CANADA Home (902) 889-3555 Science Serving the Fisheries http://home.istar.ca/~gadus