-Develop your own app for your own uses; or
-Buy an app
Option one means you'll have to learn some code (mainly Objective C) and have a Mac computer of some sort for Xcode (their development tool). If you want to sell it in the App Store, you'll also need to pay to be a developer, which is currently $99 as an individual.
Option two often means you're only getting generic values for the aircraft type, and not your specific aircraft. Even if they allow editing of the basic operating weight, several apps require you to pay for each additional aircraft type. I'll spare you my rant on what I think of that type of practice, however.
Developing your own "app" - the term loosely used in this case - isn't as tough as it needs to be. If you have a Google account, simple Excel skills, and an iPad, you have all you'll need. Having a Google account, such as a Gmail account, means that you also have Google Drive and its related Google Docs feature. This means that you can create Excel-type spreadsheets that live in the cloud, and can be stored offline on your iPad, using the free Google Drive app. While it isn't going to be as elegant as a fully-developed application, it's better than not doing your weight and balance because you hate math, don't have a calculator, or don't want to go digging through the POH for the numbers.Here's how to do it:
Grab your iPad, open up the App Store, search for Google Drive, and let that download. Once it's ready, sign in using your Google Account. Unless you've used your Drive before, you probably won't see much in there, which is just fine. Set the iPad aside and move to a computer. While you could probably do this next step on your iPad, it wouldn't be fun.
Once you're at your computer, open up an internet browser and go to drive.google.com. If this is the first time you've been there, you'll have to sign in. Once you're in, click the Create button near the top left of the screen. The fourth option down should be one for a spreadsheet. When the spreadsheet opens up, you can use this to create your own weight and balance form. Use the values right out of the weight and balance section of your POH, and go from there. If you've used Excel before, you can use many of the same functions here (SUM, IF, and simple math functions using +, -, *, / ).
After you've finished your file, open the Google Drive app on your iPad, find the file, and click the arrow on the right side. In the pane that opens, change the Available Offline slider from OFF to ON. You now have a cached version of the file on your iPad to use offline, which is important if you have a wireless-only iPad, or are away from a data connection in general.
Some hints for you:
- If you have the POH around, use the values in your POH. If you rent, whoever you rent from will often be able to fax something to you, or email the numbers.
- My images have flagged checks (green Yes boxes that change to a red No when over limits), which are based on the CG envelope and max weights. Many CG envelopes are non-linear, which means they're more complicated functions. Don't feel like you have to add them in.
- If you are using gallons of fuel, don't forget to have the function change volume to weight (many quote 100LL at 6.01lb/gal).
- Checking to make sure you're within limits for the whole flight is important. You can easily do this by setting aside cells for fuel burn per hour, and the trip length in hours. Subtract the fuel used over the trip from the total weight for your landing weight.
Please do not use the numbers from my images in your spreadsheets, as each aircraft has a different basic empty weight at a minimum. This value changes for different avionics, engine types, prop types, and various other equipment options.
It is very important that you use the values for the aircraft you will be flying.
