Originally Posted by
srilm
As a pilot, I always assumed mileage was based on the filed flight plan (which is canned and the same every day, unless changed due to weather, etc.).
So if they changed the routing on the canned flight plan, the mileage would change. ... SR
actually the filed flight plan regularly varies ... look at any random flight (esp a long-haul) on flightaware.com for a period of several days ... there are several "canned" plans for any given origin and destination, but I'd guess the dispatchers decide (probably based on enroute winds and weather, among other factors) what is filed on any particular day ... here's my wife's flight last month
filed: MICAH J220 BUF J531 SSM YQT J500 YYN J530 GTF J36 MLP GLASR7
track: Flown: 2569 sm
http://flightaware.com/live/flight/U...215Z/KIAD/KSEA
compared to the past several days
filed: BUFFR J518 IHD J518 DJB CRL J34 RWF J90 ABR J70 DIK J36 MLP GLASR7
yesterday's track: Planned: 2,344 sm Flown: 2,408 sm
http://flightaware.com/live/flight/U...215Z/KIAD/KSEA
but the airline only gives credit for Great Circle distance (2302 sm)