Chai Air Times "Pro"

so you don't miss out while flying...

Choose the correct orientation of the hemispheres depending which way your airplane is flying.

Use the map buttons to choose between the topographical and time zone maps.  The map type can also be changed later.

If you choose the time zone map, you can pick your departure points and arrival points using a mouse (activate that mode by clicking the "Mouse" mode radio buttons).

Flight information from previous flights are stored in templates and can be recalled to predefine Steps 1-3. (See Picture 3).  Click on one of the desired row to reload a template.  This is invaluable for beginning the program when using GPS enabled navigation as soon as possible after the pilot allows the use of electronic devices.  (I.e., prepare Steps 1-3 before the flight, store it, and then recall it.)

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At the onset of the flight, the ideal great circle route fit (third fit type) should be used since the actual air path is still unknown.

After the flight path becomes apparent, the great circle fit should be erased and a more accurate one used in its place. The first fit type, i.e., way points connected by great circles, usually gives the best fit in most situations.

The topographical and timezone maps can be panned and zoomed. Left click on the maps at any zoom level or pan position to add fit points, etc.  LANDSAT satellite maps can be used for all the map functions that are available for the other maps.

The day/night terminator can also be shown by pressing the day/night button.  The terminator is calculated in a manner that takes account of atmospheric refraction and thereby represents the mishor sunrise/sunset on the ground to an accuracy of approximately a minute.

Click on the LANDSAT maps to add fit points, etc.  Pan it along the entire world to follow your flight and watch the approach of sunrise/sunset to your airplane's position to accuracies of bettter than a minute (ideal for davening k'vasikin).  Click on the Solar Altitude "HUD" button (next to the "Help" button) to graphically display solar altitudes and azimuths (not shown in the picture) along the flight path when running the cursor within longitude range of the air route.

When the flight path is changed, the "Reedit" button is pushed and the fit can be re-edited.  This usually consists of using the "Undo" button and then clicking on new way points (or spline points for the third type of fit, i.e., the polynomial fit).

Click on the "Next" button to finish.  The fit is drawn in red.

GPS enabled navigation: Choose the "GPS determines the flight path whenever possible" in Step 2.  Your GPS unit will determine the flight path automatically and keep the zemanim updated.  (To use this option you must have a NMEA v3 083 compatible USB GPS dongle.)    GPS navigation can be used to daven k'vasikin to a minute accuracy.  That is, one waits until the day terminator intersects with the airplane's position.  That moment corresponds to the mishor netz on the ground to about a minute accuracy.  To determine the moment of intersection to maximum accuracy, it is advisable to watch for the intersection while using the LANDSAT maps.

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Fill in the information on your ticket.  For most parts of the world, it is no longer necessary to click the Daylight Saving (DST) check boxes, since the program will automatically determine if DST is in effect in the departure and arrival airports.  Use the "Reset" buttons to zero the times.  Use "Equate.." button to make the departure and arrival dates equal.

After the plane takes off, you should update the departure time with the actual take-off time from the runway for the "Departure Time" (unlike the case for the online times).  If you are using GPS assisted navigation, then the program will adjust the arrival time you entered before take-off based on the actual velocity of the airplane during its flight.  In the case GPS reception is spotty, the program may not have enough information to determine the correct arrival time.  To rectify this situation, at any time enter the predicted arrival time that your airplane has displayed on the consoles during flight, and press the "pin" button.  This will fix the arrival time throughout the calculations to be consistent with the new predicted arrival time.

Choose the format of how you want the zemanim to appear (i.e., according to which time zone your watch is set, and whether to use a 24 hour or AM/PM format)

Click the "Next" button to calculate the zemanim

Click on any of the zemanim to see where they occur along the flight path.

Click on the "Browser" button to calculate your individualized "Chai Air Times" table.  You can use your browser to print out approximate tables before your flight.

Store the route information with the "Save" button.  (Note that you are also requested to save the information before exiting the program.)

Check the time zone and Daylight Saving Time status read from your computer.

Click the "Next" button to display the zemanim on the flight path

Set Alarms to sound before reaching a zman by depressing the button for that zman and entering the number of minutes to sound before the zman is reached.  After activating an alarm, a countdown to the zman is displayed in blue.  When the alarm is reached, the countdown appears in red and beeps sound until the alarm is deactivated.  After the zman is reached, the word "Passed" is displayed.

Task schedule button: Sets a system wake-up call to reactivate the computer from sleep and restart the program when an alarm is reached.

Power saving button: Places the computer directly into "sleep" mode.  The computer will be woken when the alarm sounds.  Use this button to save battery life. (Note, many airlines now provide 110 V power sockets, so there is no need to place your computer into hibernation.)

Speed adjustment button: The speed of your airplane changes and will therefore gain or loose ground to the airplane marker in the program.  Adjust this by clicking the button, and then clicking on the place corresponding to the actual position of the airplane.  The zemanim will be adjusted accordingly.  This option is disabled when using GPS assisted navigation.

Adjustment Buttons and Flight Plan

As of version 2.0.0, a flight plan interface has been added that allows a simply modeling of the airplane's acceleration phase from take-off to cruise, cruise phase, and deceleration to landing phase.  Access this control with the "Flight Plan" button.  You can change your flight zemanim by modifying the parameters within the flight plan dialog, or by using the "Position" and "Speed" buttons.  If you notice that the position of your airplane is different from the program's position, then click the "Position" button and then click where the plane is actually located.  The zemanim will be recalculated after modifying the flight plan while conserving the arrival time if possible.  If you notice that the actual air velocity is different from the predicted one, use the "Speed" button to adjust it.  The zemanim will be recalculated reflecting the new speed while conserving the arrival time if possible.  (New as of version 2.4.0 (not shown): toggle buttons have been added to the speed indicator and Flight Plan dialog to switch been km/h, miles/hr to allow you follow your flights on domestic US carriers that present all their flight information in miles. The speed indicator toggle buttons can also be used to toggle between speed and distance traveled in km. and miles.)  When using GPS enabled navigation, the adjustment is disabled.  As of version 3.3, a "Restore Defaults" button as been added (see figure 10) in case the program can't find a good solution.  There are also buttons to pin the takeoff and landing times in order to help find a good solution.  (As of version 3.4, the program is much more capable of finding a good solution, and no user input should be necessary.)

GPS controls
As of version 3.0.0, effort has been dedicated to committing the program's control to a GPS device (NMEA 0183 v3 compatible USB dongle). The program user must arrange to travel with an airline that allows GPS devices onboard (lists are posted on the web) as well as reserve a window seat (to permit reliable GPS reception).  The user still needs to choose the departure and arrival airports as well as to enter the estimated times of departure and arrival.  Almost anything else can be handled automatically by the GPS device. Pictures 7 and 8 depict the new interfaces, e.g., the GPS button (which activates automatically when there is active GPS communication), as well as the GPS path trace in the Flight Plan dialog.  Figure 9 depicts the GPS button addition to the zemanim dialog (the button with the satellite icon).  By pressing that button, zemanim will be calculated at the current GPS coordinates.

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Right click on any place on the map.  A new dialog box appears.  Press the "Zemanim" button and the zemanim for that place is calculated.  You can pick the time zone and date of the calculation.  For Daylight Saving Time, check the Daylight Saving Time checkbox.

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Right click on any place on the map.  A new dialog box appears.  Press the "Solar Altitudes" button on the bottom on the dialog box.  The solar altitudes and azimuths along the route will be listed as a function of elapsed time.  The latitudes and longitudes of the flight path are also listed as a function of elapsed time.  If you click on any of the rows, that entry will light up (as a red circle) on the flight path.  The middle of the sun is on the horizon for solar altitudes equal to zero.  Dawn occurs for a solar altitude (depression) of -16.1 degrees.  Twilight occurs at a solar altitude of -8.5 degrees.

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Your installation program installs the tutorials in your program file.  Otherwise, download the video tutorials from the links given on the online documentation, and place them in your program directory. This directory is typically C:\Program Files\ChaiAirTimesPro\".  These videos can be accessed from the program's "help" button on the bottom right of the status bar. Picture 2 shows the help menu for version 4.2.0.  Notice that you can activate/deactivate finding the latest update, as well as placing the computer in "Netbook" mode. You can also change the zemanim calculations.  For example, you can choose to calculate Plag Hamincha instead of Mincha Gedolah, Sof Zman Krias Shma of the Mogen Avrohom instead of the Gro.  You can also search for sof zman Krias Shma of the morning Prayer when traveling through Polar Regions having perpetual daytime by using the opinions of either the Tiferes Yisroel (i.e., according to the departure airport), Ha Ben Ish Chai in Rav Hapoalim (12 hours equal days and nights), and the opinion of Moadim ve Zemanim (days are 24 hours long and begin at at midnight).

You can substitute Midnight for "Halochic Midnight", i.e., the program will search for the place of minimum solar depression even if the sun is up, e.g., during the summer in the Arctic.  Open a previously stored flight template by clicking on the "Open..." menu item.  When not using GPS, gain better accuracy by downloading the kml file of the flight path of the last flight of your flight number from fightaware.com and uploading using the "Open a Flightaware kml file".  Remeber to adjust the departure and arrival times and dates to reflect your own flight.