Position Points Flashcards
What is the definition of equitime point (ETP)?
POINT where it takes EQUAL TIME to fly to either a PAIR of ALTERNATES UNDER a given set of CONDITIONS;
The pair of ALTERNATES MAY or MAY NOT on TRACK
Why do we calculate ETP?
Allows us to QUICKLY DECIDE which of chose ALTERNATE airfields is CLOSEST in TIME if there is any NON-NORMAL CONDITIONS
When may ETPs become essential?
ENGINE FAILURE;
DEPRESSURISATION;
MAJOUR SYSTEM FAILURE;
ILLNESS ON BOARD
What does the term ground speed OUT refer to?
GROUND SPEED at which the aircraft TRAVELLED TO the POINT at which EVENT TOOK PLACE
What does the term ground speed ON refer to?
The GROUND SPEED to PROCEED to the DESTINATION at the TAS and the WINDS at revised altitude (if any) under NON-NORMAL CONDITIONS
What does the term ground speed HOME refer to?
The GROUND SPEED to travel BACK to the DEPARTURE aerodrome at the TAS and the WINDS at revised altitude (if any) under NON-NORMAL CONDITIONS
What ground speeds do we use to calculate distance to ETP?
Both ground speed ON and HOME;
NON-NORMAL CONDITIONS are used
What ground speeds do we use to calculate time to ETP?
Ground speed OUT;
NORMAL CONDITIONS are used
What may ETO also be referred to as?
CRITICAL POINT;
POINT OF EQUAL TIME (PET)
What are the points and distances represented in ETP?
What do they mean?
D - Total distance; X - Distance from CP to A; D-X - Distance from CP to B; H - Ground speed HOME from CP; O - Ground speed ON from CP
What is the formula that represents ETP?
X = D x H / O + H
What is the formula that represents ETP time?
T = X / G/S OUT
What does ETP(N) represent?
All engine ETP
What does ETP(1) represent?
SINGLE engine FAILURE on a TWIN engine aircraft ETP
What does ETP(3) represent?
SINGLE engine FAILURE on a 4 engine aircraft
What does ETP(D) represent?
DEPRESSURISATION FAILURE ETP
What does ETP(1D) represent?
ONE engine DEPRESSURISATION on a TWIN engine aircraft
What does ETP(3D) represent
ONE engine DEPRESSURISATION on a 4 engine aircraft ETP
How much fuel should an aircraft ideally carry?
Is this practical? Why or why not?
SUFFICIENT FUEL for a RETURN flight from DESTINATION TO DEPARTURE aerodrome;
NO, in order TO CARRY more fuel, more fuel must be BURNED, it also REDUCES commercially valuable PAYLOAD, CHANCE of DIVERSION is LOW
What is the definition of point of no return (PNR)?
The MAXIMUM DISTANCE outboard an aircraft can travel EN-ROUTE and RETURN to the DEPARTURE aerodrome, ARRIVING overhead with specified FUEL RESERVES WITHIN the constraints of its SAFE ENDURANCE
When must PNR be calculated?
When an ISOLATED DESTINATION aerodrome has NO SUITABLE ALTERNATES for the aircraft to DIVERT to in case it is NO LONGER FEASIBLE to land at DESTINATION
When are PNRs essential?
MARGINAL WEATHER at DESTINATION;
ENGINE FAILURE;
DEPRESSURISATION;
ILLNESS ON BOARD
What does it mean if you have crossed your PNR?
You are COMMITTED to LANDING at that aerodrome
What are the points and distances represented in PNR?
What do they mean?
E - (Fuel on board / fuel flow) - (mandatory reserves / fuel flow); O - Ground speed OUT; H - Ground speed HOME; D - Distance to PNR; T - Time to PNR
What is the formula that represents PNR?
D = E x O x H / O + H
What is the formula that represents PNR time?
T = E x H / O + H
What effect does wind, fuel and speed have on PNR?
NIL WIND: Gives MAXIMUM PNR DP;
ANY WIND: Reduces the PNR DP;
MORE FUEL: INCREASES PNR DP;
GREATER SPEED: INCREASES PNR DP (when all other factors are constant)
What is the definition of point of safe return (PSR)?
.
What is the definition of last point of diversion?
A PNR DO calculated to ARRIVE over the LAST EN-ROUTE ALTERNATE available with FUEL EQUAL to the specified RESERVES
What is the derived formula for PNR including the wind factor?
D = (E x TAS / 2) - (E x W^2 / 2 x TAS)
