CX vs RLM
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
CX
This aviation tool simplifies flight planning for pilots. It offers accurate calculations for time, speed, distance, fuel, and more, along with unit conversions and a built-in calculator. Designed for ease of use, it guides users through flight planning and execution with a natural menu flow.
- Flight planning calculations
- Time, speed, distance functions
- Fuel and altitude calculations
- Unit conversions (12 categories)
- Weight and balance calculations
- Holding pattern details
- Built-in calculator, clock, timer
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Based on the ASA CX-3® Flight Computer for pilots, this CX-3 app makes flight planning simple by taking confusion out of the equation. Fast, versatile and easy to use, the CX-3® delivers accurate results quickly and efficiently. Whether used for flight planning, ground school, or FAA Knowledge Exam preparation, the menu organization reflects the order in which a flight is normally planned and executed, resulting in a natural flow from one function to the next with a minimum of keystrokes. Multiple aviation functions can be performed on the CX-3® flight computer including those related to time, speed, distance, heading, wind, fuel, altitude, cloud base, standard atmosphere, glide, climb & descent, weight & balance, as well as a holding pattern function to help determine entry method and holding details. The CX-3® has 12 unit-conversions: Distance, Speed, Duration, Temperature, Pressure, Volume, Rate, Weight, Rate of Climb/Descent, Angle of Climb/Descent, Torque, and Angle. These 12 conversion categories contain 38 different conversion factors for over 100 functions. A calculator, clock, timer, and stopwatch are also built in along with multiple settings for lighting, backlighting, themes, time zones and more.
RLM
This aviation computer app offers a comprehensive suite of tools for pilots. It calculates various flight parameters, including altitude, airspeed, ground speed, wind components, and weight & balance. The app also features unit and currency conversions, making it a versatile utility for aviation professionals.
- Altitude & Cloud Base Calculations
- Airspeed & Ground Speed Calculations
- Wind Component & Correction Tools
- Weight & Balance Calculations
- Unit & Currency Conversion
- Holding Pattern & Flight Plan Tools
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The RLM-Flight app is the ultimate aviation computer. Designed with a clear beautiful interface and easy to use through direct menu selection with all variables at sight converting it in the most powerful, versatile and useful aviation computer you may have in your iOS device. The RLM-Flight has a extensive Menu System: >Altitude & Cloud Base Worksheets: Calculate Pressure Altitude, Density Altitude, Barometric Pressure or Outside Temperature with or without humidity. Also calculates the Cloud Base above ground and Clouds Temperature knowing the Outside Temperature and Dew Point. >Standard Atmosphere: Calculate the Altitude, Temperature or Pressure and the Air Density and Speed of Sound in the International Standard Atmosphere (ISA). > Airspeed Calculations: Calculate the True Air Speed, Calibrated Air Speed, Outside Temperature, Mach number, Total Air Temperature or Pressure Altitude. >Ground Speed & Fuel Rate: Calculate the Ground Speed, Distance, Duration or Fuel consumption. >Glide & Climb/Descent: Calculate Horizontal Distance, Glide Ratio, Descent or Climb Altitude, Angle and Ratio. >Wind Components: Calculate Cross Wind, Head Wind, Run Way, Wind Speed or Wind Direction. >Wind Correction: Calculates the Ground Speed, True Course, True Air Speed, True Heading, Wind Speed or Wind Direction and the Wind Correction Angle. >Compass Heading: Calculate True Heading, Magnetic Heading, Compass Heading, Variation or Deviation. >Holding Pattern & From-To: Calculate the type of entry necessary and the inbound heading to enter in a holding pattern given by the airplane Heading, the Holding Radial and the standard turn (left or right). Also, convert the course from a location into the course to the same location. >Rhumb Line: Calculate the True Course, Rhumb Line Distance and the Great Circle Distance for flight paths specified by latitude and longitude. >Flight Plan: Calculate the Total Distance, Estimated Time in Route, Estimated Time of Arrival and Fuel Burned in a cross country flight composed of an arbitrary number of legs. >Weight & Balance: Calculates the total weight and the resulting center of gravity of an airplane base on the loads arms, weights and/or moments of different items including the empty aircraft weight and center of gravity, pilots, passengers, fuel and cargo areas. >Weight Shift & %MAC: Calculate the change in Center of Gravity, change in Weight, change in Arm or total Weight given the others. Also calculate the %MAC, Center of Gravity, Mean Aerodynamic Chord or Leading Edge of MAC given the others. >Units Conversion: powerful and completely customizable physical units conversion calculations. >Currency Conversion: to calculate currency exchanges between two selected world currencies and common crypto currencies with manual or on-line rates. > Math Functions: to apply scientific functions to the displayed number including angles conversion, trigonometric functions, logarithmic function, decimal hour to hour:minute:seconds, etc. System requirements: iOS 15.0 or above. 30 days Free-Trial. In-App-Purchase: One-Payment for life. License Agreement: http://www.apple.com/legal/itunes/appstore/dev/stdeula DISCLAIMER: THE “RLM-Flight” SOFTWARE IS PROVIDED TO YOU ON AN "AS IS" BASIS. THE SOFTWARE IS NOT CERTIFIED BY ANY AUTHORITY AT THE MOMENT AND THE USER ASUMES ALL THE RESPONSIBILITY OF IT USE. THE LICENSOR DOES NOT REPRESENT OR WARRANT THAT THE SOFTWARE CALCULATIONS OR DATA MADE WILL BE FREE FROM MISTAKES OR ANY OTHER DEFECTS OR ERRORS AND THAT ANY SUCH EFFECTS OR ERRORS WILL BE CORRECTED, OR THAT IT WILL OPERATE WITHOUT INTERRUPTION. YOU AGREE THAT YOU ARE SOLELY RESPONSIBLE FOR ALL COSTS AND EXPENSES ASSOCIATED WITH RECTIFICATION, REPAIR OR DAMAGE CAUSED BY SUCH DEFECTS, ERRORS OR INTERRUPTIONS.
Screenshots
Verdict
The clearest difference is price: RLM at Free against CX's $19.99. RLM also leads on rating (5.0 vs 3.7) and update cadence (every 3 weeks vs every 8 months). CX's advantage is in-app purchases (none vs 1) and chart position (#71 vs unranked). On ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
RLM is free to download; CX costs $19.99 up front. RLM sells 1 one-off in-app purchase. CX asks for nothing beyond the download.
RLM holds the better App Store score, 5.0 against 3.7. That said, the two scores are not equally well evidenced: CX has 11 ratings behind it against 2, so its average is the more settled of the two.
CX ships an update every 8 months, RLM every 3 weeks. The most recent releases landed on September 22, 2026 and September 10, 2026 respectively.
| Parameter | CX | RLM |
|---|---|---|
| Price | $19.99 | Free — better |
| Rating | 3.7 (11 ratings) | 5.0 (2 ratings) — better |
| Positive reviews | 35.7% of reviews | — |
| Number of ratings | 11 — better | 2 |
| Update frequency | Every 8 months | Every 3 weeks — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Paid | Free — better |
| Best chart rank | #71 — better | — |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 17.2 | 15.0 — better |
| Further details — not scored | ||
| Size | 3 MB | 6 MB |
| Age rating | 4+ | 4+ |
| Developer | ASA | R.L.M. Software |
Customer experience
CX
RLM
In-app purchases
CX
No in-app purchases
RLM
- Lifetime Full Access$9.99









