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How to Use the TOPCAT Takeoff and Landing Calculator

TOPCAT stands for Take-Off Performance Calculation Tool. It is a shareware takeoff and landing performance calculator intended specifically for use with PMDG simulations of the 747-400 and the 747-400F. It was developed and is distributed by Christian Grill. The software has been under continuous development for several years now. New versions with new features are released on a regular basis. Most recently, the developer is expanding the software to make calculations for other aircraft types. The first of these is the 767-300 series. TOPCAT's primary function is to assist flight simulation enthusiasts in making realistic performance calculations that closely match the way these calculations are made by airline pilots in the real world. The software is designed to simulate laptop performance calculators that are often used today on modern airliners. These calculators typically go beyond what onboard flight computers are capable of doing. It allows the user to make calculations based not only on an aircraft's flight model, and current weight, but which also take into account the parameters of the runway to be used, current weather conditions, and the particular technique that the pilot intends to use.

Things You'll Need

Microsoft Flight Simulator
The PMDG 747-400 or other compatible aircraft model
An Internet connection
TOPCAT calculator

Instructions

Getting Started
- 1
  Download the TOPCAT software (see the Resources section below for a link).
- 2
  Unzip the file to a location of your choosing and open the folder.
- 3
  Right-click on the TOPCAT icon and make a shortcut to your desktop.
- 4
  Run TOPCAT. When the software boots up, you will see a screen with a timer. As this is the free trial version, you must wait for the timer to count down before using it. You will also be given the option of purchasing a full license. The trial version is identical in functionality to the fully-licensed version, except that you must wait for the timer to count down each time you run the software or make a calculation. The choice to purchase a license is up to you.
- 5
  Follow the instructions to add your first aircraft to the library. The program allows you to set up different default settings for individual aircraft tail numbers. This is especially useful if you are flying for a virtual airline. You must enter at least one tail number for each aircraft type that you are using. If you are uninterested in this feature, then just make up a tail number and forget about it. Just be aware that you must add at least one aircraft with the specifications you plan to fly with. TOPCAT will calculate differently based on the layout and engine type of the plane you will fly, so be sure to select the specs to match your aircraft of choice.
Takeoff Calculations
- 6
  Click the "Aircraft" tab and choose the specific plane you intend to fly. See Step 5 in the section above if you have not added a plane yet.
- 7
  Click the "Loading" tab and fill in the data for how your aircraft will be loaded. These numbers should be a part of your flight planning routine, and include data for passengers, cargo, fuel and aircraft weight and balance.
- 8
  Click the "Takeoff" tab and start by entering the ICAO code for the airport from which you will depart. Wait a moment for the relevant airport data to be loaded, then continue by selecting the departure runway and the current weather conditions. If needed, you may go to the "weather " tab and download weather details for your airport. Finally, enter the planned gross takeoff weight and the takeoff configuration you wish to use (flaps, thrust config, air packs, anti-ice, etc.). All of these items will affect the final takeoff calculations.
- 9
  Click the "Compute" button at the lower right of the screen. Once more, you will be shown a timer and asked to buy a license to get rid of the timer. Wait for the timer to finish and click "continue" to see the results of your calculations.
- 10
  Enter the results into the flight computer of your aircraft. The results include V-speed calculations and information about assumed temperatures for use with de-rated thrust configurations. If you are unfamiliar with these, consult the operator's handbook of the aircraft you are flying.
Landing Calculations
- 11
  Click the "Aircraft" tab, and choose the specific plane you intend to fly. See Step 5 of Section 1 if you have not added a plane to the library yet.
- 12
  Click the "Loading" tab and fill in the data for how your aircraft will be loaded. These numbers should be a part of your flightplanning routine, and include data for passengers, cargo, fuel and aircraft weight and balance.
- 13
  Click the "Landing" tab and start by entering the ICAO code for you destination airport. Continue by inputting the runway you intend to use and the current weather conditions. If needed, you may go to the "weather " tab and download weather details for your airport. Finally, enter the planned landing weight, and the landing configuration you wish to use (flaps, air packs, anti-ice, etc.). All of these items will affect the final landing calculations.
- 14
  Click the "Compute" button at the lower right of the screen. Once more, you will be shown a timer and asked to buy a license to get rid of the timer. Wait for the timer to finish and click "continue" to see the results of your calculations.
- 15
  Enter the results into the flight computer of your aircraft. The results include V-speed calculations and estimates for runway margins. Note that TOPCAT will also display estimated margins for the runway you have chosen.

Aviation