WMO table 008004: PHASE OF AIRCRAFT FLIGHT code meaning ---- ------- 0 RESERVED 1 RESERVED 2 UNSTEADY (UNS) 3 LEVEL FLIGHT, ROUTINE OBSERVATION (LVR) 4 LEVEL FLIGHT, HIGHEST WIND ENCOUNTERED (LVW) 5 ASCENDING (ASC) 6 DESCENDING (DES) 7 MISSING VALUE