Frequently Asked Questions
What charts does the ASA Fixed Plotter CP-1 work with?
The CP-1 carries six scales: sectional (1:500,000), WAC (1:1,000,000) and terminal area (1:250,000), each in nautical miles on one side and statute miles on the other. ASA designed the six scales to meet the needs of all VFR aeronautical charts, so one plotter handles every chart in your flight bag.
Does the CP-1 measure in both nautical and statute miles?
Yes. One side of the plotter reads nautical miles and the other side reads statute miles. A conversion scale turns nautical miles into statute miles at a glance, so you can work in whichever unit your aircraft and references use.
How do you find a true course with a fixed plotter?
Draw a line on your chart between the points that define your route. Align the top edge of the plotter with the course line and slide it along the line until the center hole falls over a line of longitude or latitude. Read the true course at the top of the protractor where it crosses that line.
How do you convert true course to magnetic course?
Find the magenta dashed magnetic variation line closest to your course line and apply that variation to the true course you measured. If the variation is easterly, subtract it; if it is westerly, add it. The memory aid is east is least, west is best.
How do you measure distance on a sectional chart with the CP-1?
Choose the plotter scale that matches the chart you are using, such as the sectional scale for a sectional chart. Align the plotter edge between the two points and read the distance directly from the plotter. Measure each leg point to point and add the legs together for your total route distance.
Can you measure distance from a VOR with this plotter?
Yes. Place the hole in the center of the plotter over the VOR symbol on your chart and align the top edge of the plotter with your course line. Measure distances outward from the center, making sure you read the scale that matches your chart.
What is the difference between a fixed plotter and a rotating plotter?
Both measure courses and distances on the same charts. A fixed plotter reads the angle off a printed protractor that you line up with a line of longitude or latitude, while a rotating plotter uses a spinning azimuth wheel. Many pilots like the fixed design for its simplicity, with no moving parts to slip or wear.
What is the ASA Fixed Plotter made of?
It is made of sturdy clear plastic with easy-to-read numbers and scales. The clear body lets you see your course line and the chart features underneath while you measure.
Is the CP-1 accurate?
ASA reports that the plotter has been checked and approved by the Weights and Measures Department. Matching scales are printed for sectional, WAC and terminal area charts, so you read distances directly instead of converting from the chart legend.
Does the plotter need batteries?
No. The CP-1 is a fully manual tool with no batteries or power, so it is always ready for preflight planning and works as a dependable backup to an EFB or GPS.
Is a plotter useful for student pilots and the checkride?
Yes. Plotting a course and measuring distances by hand is a core part of VFR cross-country planning in flight training, and examiners commonly look for that manual dead reckoning skill alongside electronic tools. A simple fixed plotter is an easy, affordable way to build it.
Who makes the ASA Fixed Plotter and what is the part number?
The plotter is made by ASA (Aviation Supplies and Academics) as part of its AirClassics line. The manufacturer part number is ASA-CP-1, and the plotter is made in Korea.

