FlightCalc.com is working hard to bring to the internet a host of aviation related services, which are completely free. Although we work diligently to make sure our data is sound, we cannot guarantee or warranty any of the data, and do not recommend anyone use FlightCalc.com to formally plan a flight of any kind. FlightCalc.com offers aviation books for sale in conjunction with Amazon.com and is not responsible for sales orders that are placed with Amazon.com or any of it's subsidiaries. All customer service and technical support related to books purchased from FlightCalc.com should be directed to Amazon.com. If you have any questions or suggestions about FlightCalc.com, please email us. Thanks, and have a happy and safe flight, Andy Sharpe, President FlightCalc.com