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Ambiguous commands, and 'to' vs. 'two'

Posted by Lee Baker on Tuesday December 12, 2017

The problem:

A common problem that I have been having while using PlaneCommand 3 betas involved confusing "to" and "two", since they sound exactly the same. For example, what if you say "set altitude to one thousand feet" vs "set altitude two one thousand feet"? Is that 1,000 feet, or is that 21,000 feet? They sound identical, and it's difficult for PlaneCommand to figure out the intent here.

The flawed fix:

I changed PlaneCommand: you can no longer say "to" right before a number like a frequency, heading, altitude, etc. I've never actually asked a pilot about this, but the word "to" seems pretty rare in the cockpit phraseology I've heard, perhaps in order to avoid this problem in the real world.

Since I released 3.0.2, I've realized this is a mistake- flightsimmers love to use 'to' in their commands, like "Set COM-1 to 1-3-4-point-5" etc. It just feels more natural. I think I will have to add 'to' back in.

In a lot of situations, PlaneCommand actually deals with the extra "to" pretty well. It knows a lot of ways to phrase a command, and will try to force your command to match the most similar command it knows. If you say "Set COM-1 to 1-3-4-point-5", it doesn't understand that command, but does know "Set COM-1 1-3-4-point-5", it will decide that they are similar enough, and accept the command.

Sometimes, it gets it wrong. Maybe it doesn't hear some words clearly. Maybe the user has a crappy microphone. Maybe the user pauses between words in a way the computer wasn't expecting. Maybe a truck drives by and creates background noise. And then it thinks it hears something different than what you said, and does something other than what you wanted. If it's just way too confused about what was said, PlaneCommand will just ignore it and do nothing.

Moving forward:

With that said, I'm trying to figure out what to do in future versions of PlaneCommand. It's infeasible to train all flightsimmers to never say the word "to", so I think I've got to figure out how to accept commands with "to", with the fewest ambiguous situations possible.

I hope this explains what was going on; this is definitely something that will be addressed soon.

About PlaneCommand

PlaneCommand is an add-on plugin for PC flight simulators uses speech recognition technology to emulate a co-pilot. The voice interface frees virtual pilots from needing to memorize arbitrary keyboard commands, and provides a natural speech interface to many common cockpit instruments. Realism is enhanced by assisting the pilot with common cockpit tasks like tuning radios or configuring instruments.

PlaneCommand supports the X-Plane 10 and 11 flight simulators on Windows and Mac OS, and fully supports VR. Support for Microsoft Flight Simulator coming soon. A free demo version is available for download, and the full PlaneCommand Pro license is available to purchase at

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