Airline flight plans require airline dispatch offices to monitor the progress of weather along the routes of their flights, helping the pilots to avoid the worst of inflight icing conditions. Aircraft can also be equipped with an ice detector in order to warn pilots to leave unexpected ice accumulation areas, before the situation becomes critical. Pitot tubes in modern airplanes and helicopters have been provided with the function of "Pitot Heating" to prevent accidents like Air France Flight 447 caused by the pitot tube freezing and giving false readings.