CP/PNR

Question 1

What is the formula for CP?

Answer 1

Distance to CP (from HOME) =

Total Distance (between aerodrome) x Ground Speed HM
—————————————————————
Ground Speed HM+ Ground Speed ON

CP=
DIST x GSH
—————
GSH + GSO

Question 2

What is the EPNR formula?

Answer 2

EPNR =

FFA (-1600 if BRW)
———————-
ESGR OUT + ESGR HOME

To estimate PNR don’t forget to revise FFA if fix is not overhead HOME. Use standard SGRs with allowances for EPNR.

Flight plan to EPNR

Adjust PNR accordingly.

Question 3

What RSWT and Mach is used for 1 Engine INOP?

Answer 3

Need to find altitude capability

FL235 RSWT and LRC Mach for EMZW (approx TAS 420)

Question 4

What RSWT and Mach is used for DEPRESSURISED?

Answer 4

FL185 RSWT and M.59

Question 5

What effect does wind have on CP?

Answer 5

CP mostly always into wind

Question 6

Where does the estimated CP lie?

Answer 6

Estimate CP as half way or close waypoint/subdivision into wind

Question 7

What effect does wind have on PNR?

Answer 7

PNR farthest from departure in NIL WIND

PNR closer to departure in ANY WIND

Question 8

What is the PNR dependant on?

Answer 8

Flight Fuel Available

Question 9

How do you calculate Flight Fuel Available for the calculation of a PNR?

Answer 9

FFA =
FOB-taxi/shutdown (unless in flight calc), holding, fixed reserve, variable reserve (not for DP).

Revise FFA if in flight calc being made and fix not over HOME.

RFFA =
FFA - (appropriate SGR x distance from fix to HOME)

Question 10

What would you estimate a PNR Minimum Landing Weight?

Answer 10

ELW = BRW or GW at fix - FFA

Question 11

What information is required to calculate Depressurised Critical Point?

Answer 11

• Total distance
• Ground speeds ON and HOME @FL130
• Average tracks, winds and temperatures from roughly half way ON and a HOME

Question 12

What information is required to calculate OEI Critical Point?

Answer 12

• Total distance
• Ground speeds ON and HOME at hemispherical level according to GW altitude capability
• Average track, wind and temps