"a 2c difference makes a 1,500 kg difference on a B772"
Are you from the school of pilots who dabble in deciding at what point does 23c become 24c? Are you getting stressed over 1,500kg in a B772? I'm sure that you could easily have a 800kg fuel gage error; . . . and the other 700kg you could "legally" write off for APU burn . . . no?
Just curious, if for absolute technical, super accuracy you had to offload 1,500kg baggage, would the money be coming out of your pocket...?
John Hill: ideally, it's not adventageous to place the thermometer near the runway, as it would be affected by the heat from jet exhausts.