INPUT: flightID is a two-character string to identify which payload through a flight inumber (e.g., '1A') OUTPUT: [[a1,a2],[b1,b2],[c1,c2]] is a list of 3 sets of linear model coefficients, used by brl_makeedges() METHOD: linear search; guess if unrecognized input REVISION HISTORY: 16Jan2014 Added constants for payload 2I 14Sep2013 first version