Aviation Supplies CX-2 User manual

Flight Computer
Aviation Supplies & Academics, Inc.
Newcastle, Washington 98059-3153
CX-2 Manual 05/15/2007 11:17 AM Page 1

2
CX-2 Pathfinder
Flight Computer Instructions
© 2001 – 2007 ASA
All rights reserved. Published 2001.
AirClassics and CX-2 are trademarks
of Aviation Supplies & Academics, Inc.
Aviation Supplies & Academics, Inc.
7005 132nd Place SE
Newcastle, WA 98059-3153
www.asa2fly.com
Printed in China
11 10 09 08 07 9 8 7 6 5 4 3
Visit the ASA website (www.asa2fly.com) for any manual
revisions, technical support, and FAQs for this product as
they become available.
CX-2 Manual 05/15/2007 11:17 AM Page 2

CONTENTS
Page
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . .5
KEYPAD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
GETTING STARTED . . . . . . . . . . . . . . . . . . . . . .10
CONVERSIONS . . . . . . . . . . . . . . . . . . . . . . . . .11
Nautical to Statute/Statute to Nautical . . . .11
Nautical to Kilometers/
Kilometers to Nautical . . . . . . . . . . . . . . .11
Kilometers to Statute/
Statute to Kilometers . . . . . . . . . . . . . . . .12
Feet to Meters/Meters to Feet . . . . . . . . . . .12
Pounds to Kilograms/
Kilograms to Pounds . . . . . . . . . . . . . . . . .13
Gallons to Liters/Liters to Gallons . . . . . . . . .13
H.h to HH:MM:SS/HH:MM:SS to H.h . . . . . . .13
Fahrenheit to Celsius/
Celsius to Fahrenheit . . . . . . . . . . . . . . . .14
Millibars to Inches/Inches to Millibars . . . . . .15
MENU SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . .15
CALCULATOR . . . . . . . . . . . . . . . . . . . . . . . . . .18
FLIGHT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Altitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Press Alt . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Density Alt . . . . . . . . . . . . . . . . . . . . . . . . .20
Std Atmos . . . . . . . . . . . . . . . . . . . . . . . . .20
Cloud Base . . . . . . . . . . . . . . . . . . . . . . . . .21
Airspeed . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Plan TAS . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Act TAS . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Req CAS . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Plan MACH# . . . . . . . . . . . . . . . . . . . . . . . .25
Act MACH# . . . . . . . . . . . . . . . . . . . . . . . .26
3
Continued
CX-2 Manual 05/15/2007 11:17 AM Page 3

Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Fuel Burn . . . . . . . . . . . . . . . . . . . . . . . . . .26
Fuel Rate . . . . . . . . . . . . . . . . . . . . . . . . . .27
Endurance . . . . . . . . . . . . . . . . . . . . . . . . .27
Plan Leg . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Hdg/GS . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Hdg/TAS . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Compass Hdg . . . . . . . . . . . . . . . . . . . . . .30
Leg Time . . . . . . . . . . . . . . . . . . . . . . . . . .31
ETA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
To/From . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Act Leg . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Dist Flown . . . . . . . . . . . . . . . . . . . . . . . . .33
GS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Unknown Wind . . . . . . . . . . . . . . . . . . . . .34
X/H-Wind . . . . . . . . . . . . . . . . . . . . . . . . . .34
Gliding . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Glide Dist . . . . . . . . . . . . . . . . . . . . . . . . . .35
Glide Desc . . . . . . . . . . . . . . . . . . . . . . . . .36
Glide Ratio . . . . . . . . . . . . . . . . . . . . . . . . .36
WT/BAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
CLOCK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
TIMER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
Stopwatch . . . . . . . . . . . . . . . . . . . . . . . . . . .46
Count Down . . . . . . . . . . . . . . . . . . . . . . . . .46
APPENDIX A: Sample Problems . . . . . . . . . . . .47
APPENDIX B: Service Policy . . . . . . . . . . . . . . .54
Troubleshooting . . . . . . . . . . . . . . . . . . . . . .54
Battery Replacement . . . . . . . . . . . . . . . . . .55
Limited Warranty . . . . . . . . . . . . . . . . . . . .56
APPENDIX C: Abbreviations Guide . . . . . . . . .58
INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
4
CX-2 Manual 05/15/2007 11:17 AM Page 4

INTRODUCTION
ASA’ s CX-2 is the next generation of aviation comput-
ers. Using the latest microchip and display technolo-
gies, it out-performs its most sophisticated electronic
rivals.
The features of the CX-2 make it the most versatile and
useful aviation calculator available.
1. May be used for FAA Exams. The CX-2 complies
with Advisory Circular (AC) 60-11, “Test Aids and
Materials that May be Used by Airman Knowledge
Testing Applicants.” Therefore you may bring the
CX-2 with you to the testing centers for all pilot,
mechanic, and dispatcher FAA exams.
2. Numerous aviation functions. You can calculate
everything from true airspeed and Mach number, to
headwind/crosswind components and center of
cravity (CG), and everything in between. A menu
of 34 aviation functions gives you access to 40 avi-
ation calculations. The menu structure provides
easy entry, review, and editing within each function.
3. User-friendly. The LCD screen displays a menu of
functions, or the inputs and outputs of a selected
function, for easy-to-read menus and data displays.
The inputs and outputs of each function are sepa-
rated on the display screen so it is clear which num-
bers were entered and which were calculated.
Inputs and outputs are clearly labeled and the
answers or results are displayed along with their
corresponding units of measurement. The menu
organization reflects how a flight is normally
planned and executed. This results in a natural flow
5
CX-2 Manual 05/15/2007 11:17 AM Page 5

from one function to the next with a minimum of
keystrokes: to plan a flight, simply work from the
menus in sequential order as you fill in your flight
plan form.
4. Ergonomic design. The CX-2 features a very simple
keyboard and slim design. The carrying case will
protect your computer inside the flight bag, and fits
on the backside of the unit for easy storage while in
use.
5. Unit conversions. The CX-2 has 16 reciprocal unit-
conversions: nautical and statute miles, nautical
miles and kilometers, feet and meters, pounds and
kilograms, gallons and liters, time in an hours:min-
utes:seconds format and time in decimal format,
Fahrenheit and Celsius temperatures, and millibars
and inches of mercury.
6
CONTRAST
Figure 1: The CX-2 flight computer
CX-2 Manual 05/15/2007 11:17 AM Page 6

6. Timers and clocks. The CX-2 has two timers: a stop-
watch that counts up, and a count down timer. The
stopwatch can be used to keep track of elapsed time
or to determine the time required to fly a known
distance. The count down timer can be used as a
reminder to switch fuel tanks, or to determine the
missed approach point on a nonprecision instru-
ment approach. An internal clock continues run-
ning even when the flight computer is turned off.
Both UTC and local time can be displayed, and the
time can be set with either UTC or local time.
7. Interactive functions. The CX-2 is designed so the
functions can be used together. You can perform
“chain” calculations where the answer to a preced-
ing problem is automatically entered in subsequent
problems. Standard mathematical calculations and
conversions can be performed within each aviation
function.
KEYPAD
The CX-2’s simple keypad was made possible because
of the sophisticated display screen and menu structure.
The advantages of such a keypad are twofold: A calcu-
lator with 29 keys is simpler to use than one with 40 or
more, and it is small enough to fit in a shirt pocket.
Both advantages make the CX-2 more useful to a pilot
in day-to-day operations.
Selects each of the four
main menus.
Selects second or shifted function for other keys.
7
CX-2 Manual 05/15/2007 11:17 AM Page 7

Changes display to the previous menu.
and Used to navigate about the menu struc-
ture. When alternated with , darkens and
lightens display screen (toggle between and
the or until the desired shading is
achieved).
Selects highlighted menu item, enters current
input line when function is requesting input.
Clears current input line. In calculator mode,
clears the math completely.
8
CONTRAST
Figure 2: CX-2 keypad
CX-2 Manual 05/15/2007 11:17 AM Page 8

Changes sign (positive or negative) of current
input line.
Separates hours from minutes and minutes from
seconds on time inputs. For example, 2 hours,
38 minutes and 45 seconds will display as
02:38:45. When preceded by key, activates
the square root function.
Tu rns CX-2 on and resets to calculator mode.
When preceded by key, turns CX-2 off.
Standard arithmetic operators.
Numeric keys for selecting menu item and enter-
ing numbers. Conversion functions active if pre-
ceded by the key.
Decimal point.
Completes the calculation.
Resetting: To reset the CX-2, remove all of the batter-
ies. This will clear all stored information. The FAA
requires that all the memory in an electronic flight
computer be cleared prior to use during FAA
Knowledge Exams.
9
CX-2 Manual 05/15/2007 11:17 AM Page 9

GETTING STARTED
Push the button to turn the flight computer on.
Pressing the key followed by the key will
turn the calculator off. The CX-2 will automatically
turn off if no key is pressed for 7 minutes. This feature
prevents battery exhaustion if the computer is inadver-
tently left on.
When first turned on, the CX-2 is in calculator
mode with **Calculator** displayed at the top of the
screen. The CX-2 can be returned to this mode at any
time by pressing the key. Each time the computer
returns to the calculator mode, an internal test checks
the battery power. LOW BATTERY displays on the cal-
culator screen when less than an hour of power
remains, as a recommendation to change the batteries.
An “E” is displayed whenever the result of the
arithmetic operation is a number that exceeds 8 digits.
You may either press to clear the display, or just
type in a new number.
10
CX-2 Manual 05/15/2007 11:17 AM Page 10

CONVERSIONS
Often it is necessary to convert from one unit of meas-
urement to another. The CX-2 has 16 conversion func-
tions that are activated by pressing and releasing the
key, followed by pressing and releasing one of the
regular calculator keys. The unit conversions appear
above the regular calculator keys.
Nautical to Statute
Statute to Nautical
Many of the aviation functions of the CX-2 require dis-
tance inputs in nautical miles or speed inputs in knots
(nautical miles per hour). Many aircraft, especially
older ones, have their airspeed indicators and flight
manual set up for statute miles. The CX-2 allows you to
convert to nautical easily. For example, to convert 180
MPH to knots, key in:
You will get an answer of 156.4157 knots.
The CX-2 converts nautical to statute miles in much the
same way. To convert 200 knots to MPH, enter:
You will get a result of 230.1559 MPH.
Nautical to Kilometers
Kilometers to Nautical
These reciprocal conversions are performed in the same
way as for nautical and statute. To convert 100 KM to
nautical miles, enter:
You will get 53.99568 NM.
11
CX-2 Manual 05/15/2007 11:18 AM Page 11

To convert 200 knots to KPH (Kilometers per hour), enter:
The answer is 370.4 KPH.
Kilometers to Statute
Statute to Kilometers
The CX-2 does not have a function that allows direct
conversion of statute miles and kilometers. However,
since both can be converted to and from nautical units,
you can “chain” two conversions with an interim
answer in nautical. For example, to convert 10 kilome-
ters to statute miles, enter:
(the interim answer is 5.399568 NM), then enter:
and the final answer is 6.213712 SM.
To convert 55 MPH to KPH, enter:
The interim answer is 47.79369 knots, and the final
answer is 88.51392 KPH.
Feet to Meters
Meters to Feet
To convert 100 meters to feet, enter:
The answer is 328.084 feet.
To convert 10,000 feet to meters, enter:
The answer is 3,048 meters.
12
CX-2 Manual 05/15/2007 11:18 AM Page 12

Pounds to Kilograms
Kilograms to Pounds
To convert 2,000 pounds to kilograms, enter:
The answer is 907.1847 kilograms.
To convert 160 KG to pounds, enter:
The answer is 352.7396 pounds.
Gallons to Liters
Liters to Gallons
To convert 50 gallons to liters, enter:
The answer is 189.2706 liters.
To convert 100 liters to gallons, enter:
The answer is 26.4172 gallons.
H.h to HH:MM:SS
HH:MM:SS to H.h
The CX-2 can display time in two formats: hours, min-
utes and seconds separated by colons (HH:MM:SS), or
hours only (H.h, e.g., 2 hours, 30 minutes is displayed
as 2.5 hours), and it can convert from one mode of dis-
play to the other.
Start by entering 2 hours, 30 minutes and 30 sec-
onds. Clear the display, if necessary, by pushing .
Next, push:
13
CX-2 Manual 05/15/2007 11:18 AM Page 13

The display will be 02:30:30.
Add 30 seconds to the display by keying:
The display will be 02:31:00. The HH:MM:SS display
can be easily converted to an H.h format. To convert
the 02:31:00 in the current display, key in:
The display will be 2.516667 hours.
The maximum time in HH:MM:SS mode is 99:59:59.
For times greater than 99:59:59, the screen will display
E. Time entries of 100 or more hours must be made in
the H.h format.
Assume you plan to fly 63 nautical miles at a ground
speed of 120 knots and need to calculate the time
required. The formula is:
Distance ÷ Speed = Time
Key in:
This is 0.525 hours. To convert to HH:MM:SS, key in:
The display will be 00:31:30.
Note: This calculation and conversion may be per-
formed automatically by the “Leg Time” function in the
Plan Leg menu.
Fahrenheit to Celsius
Celsius to Fahrenheit
To convert 59° Fahrenheit to its Celsius equivalent,
enter:
The answer is 15°C.
14
CX-2 Manual 05/15/2007 11:18 AM Page 14

To convert -20° Celsius to Fahrenheit, enter:
The answer is -4°F.
Millibars to Inches
Inches to Millibars
To convert 970 mb pressure to inches of mercury, enter:
The answer is 28.64408 inches.
To convert 29.78 inches of mercury to mb, enter
The answer is 1008.467 mb
MENU SYSTEM
The CX-2 menu system is organized to reflect the natu-
ral order of flight. Simply work through the menus in
sequential order as you complete your flight plan.
Figure 3 shows the menu organization.* When a menu
is displayed, the menu items can be selected by pressing
the corresponding digit key; or you can highlight a par-
ticular choice by pressing the and keys fol-
lowed by the key. To return to the previous menu,
press the key. You can go directly to the Flight,
Wt/Bal, Clock, and Timer menus by pressing the ,
,,and hot keys. You can reach any CX-2
function with a maximum of 3 keystrokes.
15
* See Appendix C for a quick guide to names and abbreviations of the
various functions.
CX-2 Manual 05/15/2007 11:18 AM Page 15

The computer will prompt you for the inputs, and the
answers will display below the double line at the bot-
tom of the screen. The formulas used for these func-
tions require that inputs for speed be made in knots,
temperature in degrees Celsius, altitude in feet, and
time in the hours:minutes:seconds format. Fuel is dis-
16
Figure 3: All functions are within 3 clicks. The calculator is
organized for easy navigation and follows the logic associated
with flight planning of a typical flight.
CX-2 Manual 05/15/2007 11:18 AM Page 16

played as Xph, where X can be gallons, liters, or pounds
as long as the same unit is used for the Rate and Fuel.
The CX-2 will convert any headings exceeding 360 to
remain within 360°. For example, if you enter 390 for
any heading, the CX-2 will change this to 30 once you
press . All math and conversion functions can be
carried out on any input line. You may convert an out-
put (answer) through the calculator mode.
The CX-2 remembers the most recent display of vari-
ables, whether it was an input or an answer. The CX-2
will offer these again for any subsequent function
requiring the same variables for a solution. This allows
for “chains” of problems, where a value that is an
answer in one function will be automatically entered as
input in a succeeding function. If a function is repeat-
ed, any and all input lines will be re-entered automati-
cally. This allows you to repeat a calculation where only
one or two inputs are changed, with a minimum of
effort. You may delete the inputs to be changed by
pressing or simply typing in replacement numbers.
Resetting the computer will delete everything in mem-
ory. To reset the computer, remove all of the batteries.
This will reset all variables to zero.
The numbers displayed as inputs are the numbers
used in the calculations. The CX-2 will round each
input variable to a number of decimal places appropri-
ate for the variable. Similarly, each function output vari-
able is also rounded to a number of decimal places
appropriate for the variable. This rounding procedure
means the display will always be accurate for the num-
bers displayed, will keep numbers manageable, yet
allows for precise answers.
17
CX-2 Manual 05/15/2007 11:18 AM Page 17

CALCULATOR
Standard mathematics is conventional in the CX-2. The
computer performs the four standard arithmetic opera-
tions (addition, subtraction, multiplication and divi-
sion), as well as the square root function, . It
will accept input numbers up to a maximum of 7 dig-
its and dispay results with a maximum of 8 digits with
a floating decimal point and a minus sign. The sign of
any number can be changed with the key.
With the CX-2 turned on, add the numbers 123 and
456 by pressing:
The number 579 will be displayed. Now press to
change the number to:
-579
As a final step, multiply -579 by 6.5 by keying in:
resulting in the answer:
-3763.5
Refer to Appendix A for additional practice problems.
FLIGHT
Altitude
Press Alt
In aviation calculations, air pressure is normally speci-
fied by an altitude in a standard atmosphere, instead of
pounds per square inch or inches of mercury. The alti-
tude corresponding to a given pressure is called the
pressure altitude (PAlt). An aviation altimeter displays
PAlt when the altimeter setting window is adjusted to
18
CX-2 Manual 05/15/2007 11:18 AM Page 18

the standard atmospheric pressure at sea level, 29.92''
Hg. PAlt is required to calculate true airspeed (TAS)
and density altitude (DAlt).
The Press Alt function calculates PAlt, given the
indicated altitude (IAlt) and altimeter setting (Hg)
obtained from the automated flight service station
(AFSS) or Air Traffic Control (ATC). An altimeter
adjusted to this setting will indicate the altitude of the
airfield when the aircraft is on the ground.
Problem: You are planning to fly at 4,500 feet IAlt and
the current altimeter setting is 30.15'' Hg. What PAlt
should you use to calculate the TAS?
Solution: Press the key. Select the Altitude sub-
menu by pressing or highlight the Altitude line
and press . Select the Press Alt function by pressing
or highlight the Press Alt line and press . The
Press Alt function will position the curser for you to
enter IAlt. Press:
The curser will then be positioned to enter the altime-
ter setting Hg. Press:
The display will show 4,288 feet PAlt.
Problem: What is the PAlt at an airport with a field ele-
vation of 5,900 feet and a 29.75'' Hg altimeter setting?
Solution: Select the Press Alt function and enter
for IAlt and
for Hg. The display will show 6,058 feet PAlt.
19
CX-2 Manual 05/15/2007 11:18 AM Page 19

Density Alt
In aviation calculations, air density is normally speci-
fied by an altitude in a standard atmosphere, instead of
pounds per cubic foot. The altitude corresponding to a
given density is called the density altitude (DAlt). The
Density Alt function computes DAlt based on PAlt and
the outside air temperature (OAT).
Problem: What is the DAlt at an airport with a field
elevation of 5,900, 29.75'' Hg altimeter setting, and
75°F OAT?
Solution: First, calculate PAlt as shown in the previous
problem. Press to return to the Altitude menu.
Press 2 or highlight the Density Alt line and press .
The Density Alt function will automatically display
6,058 feet PAlt, just computed. Press to accept this
input. Next you are prompted for the OAT in degrees
Celsius. Press:
to enter 75° Fahrenheit, convert to Celsius, and enter
the result as the OAT input. The display will show
23.89°C OAT and 8,426 feet DAlt.
Std Atmos
Since air pressure and air density are specified by an
altitude in a standard atmosphere, you may want to
find the standard atmosphere for a given altitude. The
International Civil Aviation Organization (ICAO) has
established standard conditions for temperature and
pressure. You can enter an altitude (Alt) in the Std
Atmos function and obtain OAT in Celsius; pressure in
inches of mercury (Hg); and pressure in millibars (mb)
20
CX-2 Manual 05/15/2007 11:18 AM Page 20