Chris try looking at the plane spotters thread if you want more lulz
The pressure sensors on that tyre will read LOW (that is any point from their alarm setting to zero) so the loss of the wheel itself will give a LOW reading (the same if the sensor pipe failed or the tyre was punctured)
Either way the alarm reading or the handling of the aircraft (lateral shift of the CoG or reduction in drag to one side) should also have alerted a professional pilot to their being an issue somewhere..
I'm now looking forward to the next (let's get one over on Kymmy) attempt by this poster as it's really lifting my spirits atm