I have a new iPad app that has just been added to my favorites list: Aviation W&B, available via the App Store on your iPad for under $10!
Aviation W&B comes preconfigured with basic weight and balance information for a number of aircraft models. You can also create your own from scratch. Then, for each make/model you can add the specifics for a particular aircraft you fly and store it under its tail number.
Here’s a screen shot of the input form for the C-150 in which I taught my son to fly:
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After filling in the basic information about fuel on-board, weights of the pilot and passenger and baggage, it has computed the takeoff weight and is indicating in all GREEN text that all those parameters are OK and within CG limits. If anything was out of range or over gross it would be indicated in RED.
But notice one other thing: Maneuvering speed for this weight has been calculated. We all know (or should know!) that the maneuvering speed listed in the POH is based on maximum gross weight. You should also remember that as weight DECREASES, so does maneuvering speed. This serves as a reminder of what the maneuvering speed is for THIS flight (or at lease right after takeoff!) Obviously it will decrease further as you burn off fuel.
Once this is computed you can take a peek at where it lands within the CG envelope by tapping on the Envelope link at the bottom. You will be asked to choose the style of graph you want, either based on inches or Moment/1000. Selecting inches gets you this screen:
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We’re below gross and almost centered within the CG envelope….a safe place to fly!
Okay, so that’s cool…but now let Aviation W&B take it a step further: Where will you be when you land?
Going back to your input screen, touch on the Landing button on the bottom of the screen and you will be prompted for two more pieces of information, including fuel burn per hour and the estimated flight duration in minutes:
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Here we’re estimating a 5.5 GPH burn rate and a two hour flight. Touching the Envelope button (and this time choosing the Moment/1000 option) will give us this graph:
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Notice the takeoff CG position is indicated along with a vector towards your landing CG. We’ve confirmed that we will remain within the CG limits for our entire flight.
When all is said and done, tap the Summary button and you have a nice, clean W&B form that looks like this:
You can save a snapshot of that form to your photos or e-mail it to yourself documenting your loading configuration for your flight.
Here’s why I love this app:
- It’s on my iPad, so it is ALWAYS with me.
- It’s easily customized for EVERY aircraft I fly.
- It encourages playing “What if?” scenarios with different loading configurations.
- It encourages me to look at LANDING CG, not just takeoff CG.
- It makes me THINK about maneuvering speed for THIS aircraft on THIS flight!
- I can easily save a copy of the W&B configuration as backup documentation.
- It’s a bargain!
Okay, so now you know why I love this app.
I do have one small nit to pick with it: I HATE the disclaimer screen that pops up every time I start it stating (and I paraphrase) “You can’t rely on this in any way, shape or form because we don’t want to get sued!”
I’m a lawyer. I understand why it’s there. But it still drives me crazy.
It should go without saying that before relying on any app like this you should make all the computations the old fashioned way, then compare those results against the results obtained with the app under a variety of loading scenarios. You have to satisfy yourself that you’ve crossed all the t’s and dotted all the i’s in setting it up for your aircraft.
But once you’ve done that, you are far less likely to have a loading mishap using an app such as this than you are scribbling numbers on a sheet of paper and doing arithmetic long-hand. More importantly, you are more likely to take the time to consider loading for every takeoff and every landing when it is this easy to do. It’s a no-brainer.
Check out this app. You’ll be glad you did.