Range - Ch 10

Question 1

Specific Range

Answer 1

Distance flown per unit of fuel

Question 2

SAR

Answer 2

Specific Air Range: Air Mass related

Question 3

SGR

Answer 3

Specific Ground Range: Wind Affected

Question 4

Fuel Flow

Answer 4

Turbojet: Fuel flow is proportional to Thrust

Prop: Fuel flow is proportional to power

Question 5

SFC

Answer 5

Specific Fuel Consumption

Question 6

SFC Jet =

Answer 6

Fuel Flow / unit of thrust

Lowest: low temp, high alt, optimum rpm

Question 7

SFC Prop:

Answer 7

Fuel Flow / unit of power

Question 8

Specific Range Jet

Answer 8

= TAS / SFC x Drag

Best range - optimum rpm
1.32VMD

Question 9

Specific Range Prop

Answer 9

TAS / SFC x PWR Required

Piston: Lower altitude : full throttle height
Turboprop: High for prop but lower than Jet (high-mid 20s)

Question 10

Factors Affecting Range

Answer 10

Increasing Mass decreases range

Increasing Wind: SAR Unaffected SGR: Affected

Question 11

Wind Impacts

Answer 11

Headwind - Fly faster into it and spend less time in it
Tailwind - Fly slower in it
For a Jet.

Prop: Mental calculation to work out fuel burn and adjust accordingly

Question 12

Optimum Altitude

Answer 12

Decreases as flight continues

Aim to keep at optimum alt

Cruise climb, would be ideal but clearance issues, ops dictate a step climb

Question 13

Step Climb

Answer 13

Will be told by FMC when to

May avoid flying optimum altitude around jet streams (fuel burn considerations)

Question 14

Long Range Cruise

Answer 14

Mmlc: Operating cost + fuel cost considered 
4% faster than 1.32VMD
Reduces range by 1% (99% original)
Mmlc > Mr (max range speed)
Specific Range = 0.99 S.R. Max Range

Question 15

Cost Index

Answer 15

Time/Fuel cost balance

ECON Profile - based on cost index

Higher cost index = more fuel burn

Question 16

Cruise SPD

Answer 16

Reduces as flight goes on

If high cost index: Constant Mach Number