diff --git a/42fdr.py b/42fdr.py
new file mode 100755
index 0000000..9f99e97
--- /dev/null
+++ b/42fdr.py
@@ -0,0 +1,363 @@
+#!/usr/bin/env python3
+import argparse, csv, os, sys
+import xml.etree.ElementTree as ET
+from datetime import date, datetime, timedelta, timezone
+from enum import Enum
+from pathlib import Path
+from typing import Dict, List, TextIO, Tuple, Union
+
+
+FdrColumnWidth = 19
+
+class FileType(Enum):
+    UNKNOWN = 0
+    CSV = 1
+    KML = 2
+    GPX = 3
+
+
+class Config():
+    drefSources:Dict[str, str] = {}
+    drefDefines:List[str] = []
+    aircraft:str = 'Aircraft/Laminar Research/Cessna 172 SP/Cessna_172SP_G1000.acf'
+    outPath:str = '.'
+
+    def __init__(self, cliArgs:argparse.Namespace):
+        self.aircraft = cliArgs.aircraft
+        self.outPath = cliArgs.outputFolder
+        self.addDref('Speed', 'GndSpd', 'sim/cockpit2/gauges/indicators/ground_speed_kt', '1.0')
+
+    def addDref(self, source:str, name:str, paramPath:str, scale:str):
+        if source not in self.drefSources:
+            self.drefSources[source] = name
+            self.drefDefines.append(f'{paramPath}\t{scale}\t\t// source:{source}')
+
+
+class FdrTrackPoint():
+    TIME:datetime
+    LONG:float
+    LAT:float
+    ALTMSL:float
+    HEADING:float = 0
+    PITCH:float = 0
+    ROLL:float = 0
+
+    drefs:Dict[str, float] = None
+
+    def __init__(self):
+        self.drefs = {}
+
+
+class FdrFlight():
+    ACFT:str = ''
+    TAIL:str = ''
+    DATE:date = datetime.today()
+    PRES:float = 0
+    DISA:int = 0
+    WIND:Tuple[int, int] = (0,0)
+
+    track:List[FdrTrackPoint] = None
+
+    def __init__(self):
+        self.track = []
+        self.summary = ''
+
+
+class FlightMeta():
+    Pilot:str = None
+    TailNumber:str = None
+    DerivedOrigin:str = None
+    StartLatitude:float = None
+    StartLongitude:float = None
+    DerivedDestination:str = None
+    EndLatitude:float = None
+    EndLongitude:float = None
+    StartTime:float = None
+    EndTime:float = None
+    TotalDuration:timedelta = None
+    TotalDistance:float = None
+    InitialAttitudeSource:str = None
+    DeviceModel:str = None
+    DeviceModelDetailed:str = None
+    iOSVersion:str = None
+    BatteryLevel:float = None
+    BatteryState:str = None
+    GPSSource:str = None
+    MaximumVerticalError:float = None
+    MinimumVerticalError:float = None
+    AverageVerticalError:float = None
+    MaximumHorizontalError:float = None
+    MinimumHorizontalError:float = None
+    AverageHorizontalError:float = None
+    ImportedFrom:str = None
+    RouteWaypoints:str = None
+
+
+def main(argv:List[str]):
+    parser = argparse.ArgumentParser(description='Convert ForeFlight compatible track files into X-Plane compatible FDR files.')
+    parser.add_argument('-a', '--aircraft', default='Aircraft/Laminar Research/Cessna 172 SP/Cessna_172SP_G1000.acf', help='Path to write X-Plane compatible FDR v4 output file')
+    parser.add_argument('-o', '--outputFolder', default='.', help='Path to write X-Plane compatible FDR v4 output file')
+    parser.add_argument('trackfile', default=None, nargs='+', help='Path to one or more ForeFlight compatible track files (CSV)')
+    args = parser.parse_args()
+    
+    config = Config(args)
+    for inPath in args.trackfile:
+        trackFile = open(inPath, 'r')
+        fdrData = parseInputFile(config, trackFile, close=True)
+        outPath = getOutpath(config, inPath, fdrData)
+        fdrFile = open(outPath, 'w')
+        writeOutputFile(config, fdrFile, fdrData)
+
+
+def parseInputFile(config:Config, trackFile:TextIO, close:bool = False) -> FdrFlight:
+    filetype = getFiletype(trackFile)
+
+    if filetype == FileType.CSV:
+        return parseCsvFile(config, trackFile)
+    elif filetype == FileType.KML:
+        return parseKmlFile(config, trackFile)
+    elif filetype == FileType.GPX:
+        return parseGpxFile(config, trackFile)
+
+    if close and not trackFile.closed:
+        trackFile.close
+
+
+def getFiletype(file:TextIO) -> FileType:
+    filetype = FileType.UNKNOWN
+    startingPos = file.tell()
+
+    line = file.readline()
+    if not line.startswith('<?xml'):
+        filetype = FileType.CSV
+    else:
+        line = file.readline()
+        if line.startsWith('<kml'):
+            filetype = FileType.KML
+        elif line.startswith('<gpx'):
+            filetype = FileType.GPX
+
+    file.seek(startingPos)
+    return filetype
+
+
+def parseCsvFile(config:Config, trackFile:TextIO) -> FdrFlight:
+    flightMeta = FlightMeta()
+    fdrFlight = FdrFlight()
+
+    csvReader = csv.reader(trackFile, delimiter=',', quotechar='"')
+    metaCols = readCsvRow(csvReader)
+    metaCols.remove('Battery State') # Bug in ForeFlight
+    metaVals = readCsvRow(csvReader)
+
+    metaData = dict(zip(metaCols, metaVals))
+    for colName in metaData:
+        colValue = metaData[colName]
+        if colName == 'Tail Number':
+            flightMeta.TailNumber = colValue;
+            fdrFlight.TAIL = colValue
+        elif colName == 'Derived Origin':
+            flightMeta.DerivedOrigin = colValue
+        elif colName == 'Start Latitude':
+            flightMeta.StartLatitude = float(colValue)
+        elif colName == 'Start Longitude':
+            flightMeta.StartLongitude = float(colValue)
+        elif colName == 'Derived Destination':
+            flightMeta.DerivedDestination = colValue
+        elif colName == 'End Latitude':
+            flightMeta.EndLatitude = float(colValue)
+        elif colName == 'End Longitude':
+            flightMeta.EndLongitude = float(colValue)
+        elif colName == 'Start Time':
+            flightMeta.StartTime = datetime.fromtimestamp(float(colValue) / 1000)
+        elif colName == 'End Time':
+            flightMeta.EndTime = datetime.fromtimestamp(float(colValue) / 1000)
+        elif colName == 'Total Duration':
+            flightMeta.TotalDuration = timedelta(seconds=float(colValue))
+        elif colName == 'Total Distance':
+            flightMeta.TotalDistance = float(colValue)
+        elif colName == 'Initial Attitude Source':
+            flightMeta.InitialAttitudeSource = colValue
+        elif colName == 'Device Model':
+            flightMeta.DeviceModel = colValue
+        elif colName == 'Device Model Detailed':
+            flightMeta.DeviceModelDetailed = colValue
+        elif colName == 'iOS Version':
+            flightMeta.iOSVersion = colValue
+        elif colName == 'Battery Level':
+            flightMeta.BatteryLevel = float(colValue)
+        elif colName == 'Battery State':
+            flightMeta.BatteryState = colValue
+        elif colName == 'GPS Source':
+            flightMeta.GPSSource = colValue
+        elif colName == 'Maximum Vertical Error':
+            flightMeta.MaximumVerticalError = float(colValue)
+        elif colName == 'Minimum Vertical Error':
+            flightMeta.MinimumVerticalError = float(colValue)
+        elif colName == 'Average Vertical Error':
+            flightMeta.AverageVerticalError = float(colValue)
+        elif colName == 'Maximum Horizontal Error':
+            flightMeta.MaximumHorizontalError = float(colValue)
+        elif colName == 'Minimum Horizontal Error':
+            flightMeta.MinimumHorizontalError = float(colValue)
+        elif colName == 'Average Horizontal Error':
+            flightMeta.AverageHorizontalError = float(colValue)
+        elif colName == 'Imported From':
+            flightMeta.ImportedFrom = colValue
+        elif colName == 'Route Waypoints':
+            flightMeta.RouteWaypoints = colValue
+
+    fdrFlight.summary = flightSummary(flightMeta)
+
+    trackCols = readCsvRow(csvReader)
+    trackVals = readCsvRow(csvReader)
+    while trackVals:
+        fdrPoint = FdrTrackPoint()
+        
+        trackData = dict(zip(trackCols, trackVals))
+        for colName in trackData:
+            colValue = trackData[colName]
+
+            if colName == 'Timestamp':
+                fdrPoint.TIME = datetime.fromtimestamp(float(colValue));
+            elif colName == 'Latitude':
+                fdrPoint.LAT = float(colValue)
+            elif colName == 'Longitude':
+                fdrPoint.LONG = float(colValue)
+            elif colName == 'Altitude':
+                fdrPoint.ALTMSL = float(colValue)
+            elif colName == 'Course':
+                fdrPoint.HEADING = float(colValue)
+            elif colName == 'Bank':
+                fdrPoint.ROLL = float(colValue)
+            elif colName == 'Pitch':
+                fdrPoint.PITCH = float(colValue)
+            else:
+                for source in config.drefSources:
+                    if colName == source:
+                        fdrPoint.drefs[source] = float(colValue)
+
+        fdrFlight.track.append(fdrPoint)
+        trackVals = readCsvRow(csvReader)
+    
+    return fdrFlight
+
+
+def readCsvRow(csvFile) -> List[str]:
+    reader = None;
+    try:
+        reader = next(csvFile)
+    finally:
+        return reader
+
+
+def parseKmlFile(config:Config, trackFile:TextIO) -> FdrFlight:
+    # kml = ET.fromstringlist(trackFile.readlines())
+    raise NotImplementedError
+
+
+def parseGpxFile(config:Config, trackFile:TextIO) -> FdrFlight:
+    # gpx = ET.fromstringlist(trackFile.readlines())
+    raise NotImplementedError
+
+
+def flightSummary(flightMeta:FlightMeta) -> str:
+    hoursMinutes = str(flightMeta.TotalDuration).split(':')[:2]
+
+    return f'''{flightMeta.TailNumber} - {toMDY(flightMeta.StartTime)} {flightMeta.TotalDistance} miles{(' by '+ flightMeta.Pilot) if flightMeta.Pilot else ''} ({hoursMinutes[0]} hours and {hoursMinutes[1]} minutes)
+
+    From: {toHMS(flightMeta.StartTime)} {flightMeta.DerivedOrigin} ({flightMeta.StartLatitude}, {flightMeta.StartLongitude})
+      To: {toHMS(flightMeta.EndTime)} {flightMeta.DerivedDestination} ({flightMeta.EndLatitude}, {flightMeta.EndLongitude})
+ Planned: {flightMeta.RouteWaypoints}
+GPS/AHRS: {flightMeta.GPSSource}
+  Client: {flightMeta.DeviceModelDetailed} iOS v{flightMeta.iOSVersion}'''
+
+
+def writeOutputFile(config:Config, fdrFile:TextIO, fdrData:FdrFlight):
+    timestamp = datetime.now(timezone.utc).strftime('%Y/%m/%d %H:%M:%SZ')
+
+    fdrFile.writelines([
+        'A\n4\n',
+        '\n',
+        fdrComment(f'Generated on [{timestamp}]'),
+        fdrComment(f'This X-Plane compatible FDR file was converted from a ForeFlight track file using 42fdr.py'),
+        fdrComment('https://github.com/MadReasonable/42fdr'),
+        '\n',
+        fdrComment(fdrData.summary),
+        '\n\n',
+        fdrComment("Fields below define general data for this flight."),
+        fdrComment("ForeFlight only provides a few of the data points that X-Plane can accept.") ,
+        '\n',
+        f'ACFT, {config.aircraft}\n',
+        f'TAIL, {fdrData.TAIL}\n',
+        f'DATE, {toMDY(fdrData.DATE)}\n',
+        '\n\n',
+        fdrComment('DREFs below (if any) define additional columns beyond the 7th (Roll)'),
+        fdrComment('in the flight track data that follows.'),
+        '\n',
+        fdrDrefs(config.drefDefines),
+        '\n\n',
+        fdrComment('The remainder of this file consists of GPS/AHRS track points.'),
+        fdrComment('The timestamps beginning each row are in the same timezone as the original file.'),
+        '\n',
+        fdrColNames(config.drefSources.values()),
+    ])
+
+    for point in fdrData.track:
+        time    = toHMS(point.TIME)
+        long    = str.rjust(str(point.LONG), FdrColumnWidth)
+        lat     = str.rjust(str(point.LAT), FdrColumnWidth)
+        altMsl  = str.rjust(str(point.ALTMSL), FdrColumnWidth)
+        heading = str.rjust(str(point.HEADING), FdrColumnWidth)
+        pitch   = str.rjust(str(point.PITCH), FdrColumnWidth)
+        roll    = str.rjust(str(point.ROLL), FdrColumnWidth)
+        fdrFile.write(f'{time}, {long}, {lat}, {altMsl}, {heading}, {pitch}, {roll}')
+
+        drefValues = []
+        for dref in config.drefSources:
+            drefValues.append(str.rjust(str(point.drefs[dref]), FdrColumnWidth))
+        fdrFile.write(', '+ ', '.join(drefValues) +'\n')
+
+
+def fdrComment(comment:str):
+    return 'COMM, '+ '\nCOMM, '.join(comment.splitlines()) +'\n'
+
+
+def fdrDrefs(drefDefines:List[str]):
+    return 'DREF, ' + '\nDREF, '.join(drefDefines) +'\n'
+
+
+def fdrColNames(drefNames:List[str]):
+    names = '''COMM,                 degrees,             degrees,              ft msl,                 deg,                 deg,                 deg
+COMM,               Longitude,            Latitude,              AltMSL,                 HDG,               Pitch,                Roll'''
+
+    for drefName in drefNames:
+        names += ', '+ str.rjust(drefName, FdrColumnWidth)
+
+    return names +'\n'
+
+
+def getOutpath(config:Config, inPath:str, fdrData:FdrFlight):
+    filename = os.path.basename(inPath)
+    outPath = config.outPath or '.'
+    return Path(os.path.join(outPath, filename)).with_suffix('.fdr')
+
+
+def toMDY(time:Union[datetime,int,str]):
+    if isinstance(time, str):
+        time = int(time)
+    if isinstance(time, int):
+        time = datetime.fromtimestamp(time / 1000)
+    return time.strftime('%m/%d/%Y')
+
+
+def toHMS(time:Union[datetime,int,str]):
+    if isinstance(time, str):
+        time = int(time)
+    if isinstance(time, int):
+        time = datetime.fromtimestamp(time / 1000)
+    return time.strftime('%H:%M:%S')
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv))
\ No newline at end of file
diff --git a/README.md b/README.md
index 48bfed3..4863688 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,50 @@
 # 42fdr
-Python script to convert ForeFlight's exported flight tracks to FDR files that can be imported into X-Plane
+Python script to convert ForeFlight's exported flight tracks to X-Plane compatible FDR files
+
+**Only works with CSV files currently*
+
+
+## Installation
+Just put 42fdr.py somewhere on your computer.
+- Works with python 3.9 and above.
+- Single file with no 3rd-party dependencies.
+
+
+## Usage
+`[python3] 42fdr.py [-a Aircraft] [-o outputFolder] trackFile1 [trackFile2, trackFile3, ...]`
+
+You should be able to run 42fdr without explicitly invoking the python interpreter.
+It will convert one or more files, rename it with the `.fdr` extension, and save the output to the current working directory.
+Choose a different output path with the `-o` parameter.
+
+X-Plane requires the FDR file to specify an aircraft model for the flight and this is not provided by the ForeFlight track file.
+`Aircraft/Laminar Research/Cessna 172 SP/Cessna_172SP_G1000.acf` will be used by default. 
+Choose a different aircraft with the `-a` parameter.
+
+
+## Examples
+
+<b style='font-size:smaller'>`./42fdr.py tracklog-E529A53E-FBC7-4CAC-AB46-28C123A9038A.csv`</b>
+
+The simplest use case.  Python is installed and configured correctly, we are in a bash shell, the script is in the same folder as the track file, we are only converting one file, using the default aircraft, and it should be saved to the current folder.
+
+This will create the file:
+- `./tracklog-E529A53E-FBC7-4CAC-AB46-28C123A9038A.fdr`
+
+---
+<b style='font-size:smaller'>`python3 42fdr.py -a "Aircraft/Laminar Research/Lancair Evolution/N844X.acf" tracklog-E529A53E.csv`</b>
+
+The same as above, except the Python interpreter is called explicitly, which is needed when using Windows, and the aircraft is changed to the Lancair Evolution.
+
+This will create the file:
+- `.\tracklog-E529A53E.fdr`
+
+---
+<b style='font-size:smaller'>`python3 C:\Users\MadReasonable\bin\42fdr.py -o /Users/MadReaonble/Desktop/ tracklog-E529A53E.csv tracklog-DC7A92F3.csv`</b>
+
+Convert more than one file and send the output to the desktop.
+The script is not in the current working directory.
+
+This will create the files:
+- `C:\Users\MadReasonable\bin\tracklog-E529A53E.fdr`
+- `C:\Users\MadReasonable\bin\tracklog-DC7A92F3.fdr`
\ No newline at end of file