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1. Introduction

1.1 About fplan

The fplan application is designed to assist general aviation pilots in creating flight plans for cross country flights in powered aircraft. It was developed primarily for use on systems running the UNIX Operating System and the X11 Window System, with particular emphasis on Linux.

The input to fplan is a planfile that can be created with the user's favorite plain text editor. A self explanatory language is used to describe the flight; departure and destination airports, intermediate waypoints, navigation aids, winds aloft, and fuel consumption rates. The flight plan produced by fplan includes; wind corrected magnetic headings, distance, estimated time and fuel consumption for each leg, latitude and longitude for each checkpoint, and optional VOR fixes. A graphical preview of the flight is available on systems with X11 Windows and the XView Toolkit.

For convenience, airports or navaids can be referenced by their ICAO identifier in planfiles. The information that fplan requires is stored in database files, indexed by identifier. For users in the United States, freely distributable database files are available that were derived from information from the National Flight Data Center. This data is not certified for navigation, and should be verified before actual use. It is unfortunate, but there is no known public domain source for similar information for areas outside the United States. (See the FAQ for more information).

1.2 Copyright

This release of fplan is Copyright (c) 1998,1999 John C. Peterson, <>.

This software package is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License, version 2. A copy is included in this distribution in the file named LICENSE.

This software package is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2 for more details.

I am making this stuff available in the hope that it will be useful to other pilots, but you are the final judge of its accuracy, applicability, suitability, etc. Pilots in the United States should be sure they understand the nature of their responsibilities in the area of preflight planning. See sections 3, 103, and 151 of part 91 of the FARs for a quick refresher.

1.3 Change History

The original author of fplan is Steve Tynor. His last public release was version 1.3, which was posted to volume 30 of the USENET newsgroup, comp.sources.misc in 1992. The file CHANGE.LOG contains a detailed description of the specific changes made to the source code over its lifetime. The sections below present an overview of the changes I have made since I took over as the new maintainer.

Changes from 1.4.1 to 1.4.2

Release 1.4.2 of fplan contains an implementation of the graphical previewer based on the Gnome, Gtk+, Glib libraries. It also contains a number of bug fixes for problems reported by users. This release should still be considered a beta release! All users are encouraged to upgrade. Highlights of the bug fixes are listed below.

Changes from 1.4 to 1.4.1

Release 1.4.1 of fplan contains many changes since the last public release by Steve Tynor (version 1.3). Because of the extensive scope of my changes, this release should be considered a beta release!

There were several basic goals of my changes; review the correctness of the navigation related algorithms and improve where possible, improve the documentation and examples, improve the user interface, and improve the portability of the source code. The order roughly reflects my assigned priority, from highest to lowest. Highlights of the changes and new features are listed below.

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