Well, Cobra, you answered Tim's question. As for your questions - you are right. There are apps now days that cover a lot of our aviations calculations. But again, I'd like to have these apps on my iFly device. And since all of these apps can be put onto a spreadsheet, why not have a spreadsheet app so that each pilot can build and modify his/her sheets to suit their needs? Here is a list of sheets that I have in my aviation folder: Traffic Pattern Heading, Head/Cross Wind for Take-Off and Landing, Climb/Descend Calculations, Wind Direction & Speed, Radius of Action, True Air Speed (TAS), TAS Test, Convert - Temp., Pressure Alt., Density Alt., True Alt., Rate of Climb (Ft/nm to Ft/min), Volume & Weight Convertion, Take-Off Breakeven Wind Velocity, V-Speeds, Take-Off Roll & Climb, Weight & Balance, USA Time Zones, and Phone Numbers, to name a few. Again, yes, you can find apps for most of these calculations but having them all in a spreadsheet format makes them consistant in their use. Do I use all of these sheets on each flight? Of course not. But some of them. like Density Alt. and Take-Off Breakeven Wind Velocity, when you need them, you really need them and I don't want to be stranded on an air field out in the middle of no where with out some means of calculating the 'go, no go' decision. And before someone asks, I've long misplaced my E6B. - Jim Williams - But, I completely understand that if most people using iFly do not need to fly by the numbers, then iFly doesn't need a spreadsheet. BTW, how many people are finding that hand writing on their devices is a useful tool? (Please, I'm not trying to be sarcastic. I'm just curious. I really belive in "Nothing ventured, nothing gained."