aa - this any help?
CP and PNR
Wind component of minus means headwind.
Wind component of plus means tailwind.
CP (Point of Equal Time)
Decision point between 2 airfields from which it would take the same time to fly to either airfield.
Distance to CP (X) = DH/ (0+H).
Time to CP = X/O
X = distance to CP
D = leg distance
H = GS home
O = GS out
CP Rules, CP is independent of fuel endurance. Still air, CP is midway, CP moves into wind from still air midpoint. If wind reduces, CP towards midpoint. Inc TAS = wind reduce.
PNR (aka PSR, ROA)
Defined as that point furthest removed from departure point to which an aircraft can fly and still return to its departure point within its safe endurance.
PNR:
Distance to PNR = E x O x (H)/ (0+H)
Time to PNR: = E x (H)/ (0+H)
E = Endurance
H = TAS home
O = TAS out
PNR rules:
Max dist to PNR achieved in still air.
All wind reduces distance to PNR.
Wind Inc, dist to PNR dec. = Dec TAS
Wind Dec, dist to PNR inc = Inc TAS
Radius of Action:
E becomes Safe Endurance minus Patrol Time.