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Navigation > Nav 41 - Fuel Management > Flashcards

Nav 41 - Fuel Management Flashcards

1
Q

Why is fuel monitoring important? (4)

A

Enough fuel to complete the mission
Spot fuel leaks early
A/C fuel consumption matches predicted consumption
Be aware of fuel remaining IOT respond quickly to diversion or re-taskings

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2
Q

Define:

Cruise Control

A

The organized control of an aircraft to obtain maximum flight profile efficiency

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3
Q

What are the advantages of Cruise Control?

A

General increase in safety and efficiency during flights
Conservation of fuel on ferry flights
Optimize payloads on transport ops
Saving on fuel in long range tactical flights
Efficient fuel conservation on long range flights where maximum range is required
Controls may be adjusted properly in flight to meet any changes in predicted conditions (W/V, ramp time)

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4
Q

What are the factors that affect our decisions on cruise control?

A 
Distance
Wind component
Temperature deviation
Fuel capacity
Payload to be carried
Amount of fuel reserve required
Max allowable all-up weight at T/) and landing
Enroute weather
ATC restrictions
Fuel availability at departure and destination
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5
Q

Define

Maximum Endurance

A

Operation of an aircraft at a specific SPEED and ALTITUDE, to achieve the lowest fuel flow, an thus the maximum time airborne.

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6
Q

Define:

Maximum Range

A

Operation of an aircraft at a specific SPEED and ALTITUDE, to achieve the maximum ground range per pound of fuel, for a given load

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7
Q

What is Specific Fuel Consumption (SFC)?

A

A measure of the efficiency of an engine.

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8
Q

Define:

SFC

A

The comparison of the amount of fuel used to the amount of thrust produced.

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9
Q

Is a lower SFC good or bad?

A

Good, it means a lower amount of fuel is used to obtain the maximum amount of thrust

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10
Q

How is SFC calculated for a Turbo-jet and a Turbo-prop?

A

Turbo-jet: SFC = Fuel Flow / Thrust

Turbo-prop: SFC = Fuel Flow / ESHP

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11
Q

How is ESHP calculated?

A

ESHP = Shaft horsepower + Thrust horsepower

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12
Q

What four variables affect SFC?

A

Engine RPM
OAT
Altitude
IAS

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13
Q

An increase in the following have what effect on ESHP?

Engine RPM
OAT
Altitude
IAS

A

Increase of the following:

Engine RPM = More ESHP
OAT = Less ESHP
Altitude = Less ESHP
IAS = More ESHP

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14
Q

How does Engine RPM and SFC interact?

A

There is an optimum band for SFC and ESHP, beyond the band SFC worsens as RPM increases

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15
Q

How does OAT and SFC interact?

A

As the temperature increases, ESHP is greater than FF benefit, thus SFC worsens

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16
Q

How does Altitude and SFC interact?

A

SFC improves as altitude increases because of improving thermal efficiency

Prop efficiency decreases due to less dense air and a point is reached at a certain altitude where prop efficiency worsens to a point greater than the thermal efficiency benefit.

17
Q

How does IAS and SFC interact?

A

SFC improves with an increase in airspeed

Although thrust decreases, power output increases with an increase in speed

18
Q

Complete the ESHP summary

↑RPM =
↑OAT =
↑ALT =
↑IAS =

A 
↑RPM = ↑ ESHP
↑OAT = ↓ ESHP
↑ALT = ↓ESHP
↑IAS = ↑ ESHP
19
Q

Complete the SFC summary

Optimum RPM
TEMP
ALT
IAS

A

↓ Optimum RPM = ↓ SFC
↑ TEMP = ↑ SFC
↑ ALT = ↓ SFC then ↑ SFC
↑ IAS = ↓ SFC

20
Q

How do you get the maximum range is a turboprop aircraft?

A

RPM: Operate engines at Max Continuous RPM (Optimum RPM)
Altitude: Fly high altitudes (up to services ceiling)
IAS: Fly LRC speed
Temp: Can’t do much about this one

21
Q

What is Specific Air Range?

A

A measure of the efficiency with which an aircraft flies through the air.

22
Q

How is Specific Air Range (SAR) calculated?

A

SAR = Air Distance covered / Fuel used

    = True Air Speed / Fuel Flow
23
Q

What is Specific Ground Range (SGR)?

A

A measure of the efficiency with which an aircraft flies over the ground.

24
Q

How is SGR calculated?

A

SGR = Ground Distance covered / Fuel used

    = Ground speed / Fuel flow
25
Q

True or false

Knowing how much fuel is needed to complete a mission is a critical part of every flight.

A

True

26
Q

What document is used to complete fuel monitoring?

A

The CFPS FP

27
Q

At each point on your flight plan you can compare what?

A

Fuel remaining to your planned fuel and min fuel

28
Q

How are fuel checks taken mid-leg?

A

Determine current fuel remaining, fuel flows and record time
Determine distance/ time to next TP
Record G/S
Use current FF, G/S and DTG to estimate the fuel burn to next TP
Deduct this fuel burn from the current fuel remaining to get the projected fuel at next TP

29
Q

What factors causes changes from Planned Fuel Burn?

A 
ISA conditions not as planned
Winds different from planned
Aircraft not performing to specifications
Fuel leak
Weather avoidance
ATC re-routing
30
Q

What are some corrective actions regarding fuel for the following?

Aircraft speed
Altitude
Alternate
Route
Destination
A 
Change speed to LRC - improve SGR
Change level - improve SGR (less winds)
Change alternate - lower MIN DIV fuel
Change route - shorter route saves fuel
Change destination - divert for refuel
31
Q

How is endurance calculated?

A

Estimated route time + Time to burn arrival fuel using 1000 lbs/ hour

32
Q

What is the Fuel Analysis summary?

A

Obtain fuel reading
Compare actual to expected performance
Compare flight environment to expected environment
Analyze fuel trend to determine mission impact
If required, take corrective action

33
Q

Review Questions

What is the purpose of fuel monitoring?

A

Ensure there is enough fuel to complete mission
To spot fuel leaks early
To check aircraft fuel consumption matches predicted consumption
To be aware of fuel remaining in order to respond quickly to diversions or re-taskings

34
Q

Review Questions

There are numerous factors that affect our decision on cruise control, What are they?

A 
Distance
Wind component
Temp deviation
Fuel capacity
Payload
Fuel reserve req'd
Max weight at T/O
Max landing weight
Enroute weather
ATC restrictions
Fuel availability at dept and dest A/D
35
Q

Review Questions

What factors could affect the planned fuel burn?

A 
ISA conditions not as planned
Winds different from planned
Aircraft not performing to specifications
Fuel leak
Weather avoidance
ATC re-routing
36
Q

Review Questions

What are some corrective actions we can take to rectify a lower-than-expected fuel situation?

A 
Change speed to LRC - improve SGR
Change level - improve SGR
Change alternate - lower MIN DIV fuel
Change route - shorter route saves fuel
Change destination - divert for refuel

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