A Leg in FOS can have several letters in front of the leg number in the top of the trip or leg window.
The following is a description of each of these letters meanings:
* = (asterisk) Multiple errors. ARO and/or closed and/or endurance and/or runway length.
A = ARO. A reservation for landing or departing that airport is required. Check airport data to determine how far in advance you must call before landing or departing.
C = Airport is closed at the times you have in your leg.
D = Deadhead leg. There are no passengers booked on that leg. You may see a symbol here. Look in the Scheduling Defaults window to see what symbol has been set for deadhead.
E = Endurance. Your leg is longer than the capability of your A/C.
I = Customs. It is an international leg that is landing at an airport that does not have customs or customs is closed.
O = Overbooked.
N = Stage error. This means that the noise rating of your engines violates the noise rules of either the arrival or depart airport. A curfew may apply. See Airports and see Aircraft.
P = If a trip or leg is released without the minimum number of required crew (PIC/SIC), a āPā symbol warning will display next to the leg.
R = Runway length. The airport data says that this runway is too short based on the minimum runway length in A/C Data.
S = Standby Available. Means you have a pax designated as standby for the trip and a seat is available.
X = Leg cancelled.