Compute fuel consumption, given the burn rate and time. Explain: Fuel Consumption
Fuel Calculations are basically the same as Distance , Time and Speed
just swap DISTANCE for FUEL
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Example 1. Our Cessna is burning 25 litres an hour, what will this aircraft burn in 90 minutes? |
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| Setup | |
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1. Find the 25 on the outside
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| Read off | |
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3. Find the 120 minutes on the inside time scale. 4. Read off the outside 50, which the litres this aircraft would use in 120 minutes or 2 hours. |
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a
In this example we take look at working out a Piont of No Return (PNR),
Lets take our Auckland to Norfolk flight example at 580nm.
With a True Airspeed of 200kts and Head wind of 40kts.
Example of PNR. To fly out to 0 mn at 240 kts will take 0 Minutes or 0 Hours To fly back to Departure Airport from 0 mn at 160 kts will take 0 Minutes or 0 Hours
To check your Answer ...
Time Out of 0 Hours plus time back home of 0 Hours = 0 Hours
For the Nav Computer ** Working Yet ***
\( \frac{ G/S\ Home}{G/S\ On\ +\ G/S\ Home} \) = \( \frac{Distance\ To\ PNR }{Distance} \)
To work out your speed you need to know first ….
1. Distance travelled.
2. Time taken.
In this example we have to calculate the speed of our aircraft across the ground, Lets say we have flown 34 nm in 14 minutes.
On the Wizz wheel, Distance is on the out side and time is on the inside.
1. Distance of 34 on the outside
2. Time on the inside of 14 mins.
Now we have Distance and Time Ratio setup.
3. Find the time of 60 / Hour on the inside (as time is on the inside).
4. Read off the speed of 146 the on outside. This is distance in an hour,thus your speed is 146 knots
a
Here is the Formula to the Point of No Return.
Point of No Return(Distance) = ( frac{Endurance x Ground Out Home x Ground Speed Home}{Ground Speed Out + Ground Speed Home} )
Point of No Return(Time) = ( frac{Endurance x Ground Speed Home}{Ground Speed Out + Ground Speed Home} )
| Endurance | Ratio / Time | Distance |
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| Endurance x | ( frac{ Ground Speed Home }{Ground Speed Out + Ground Speed Home} ) | x Ground Speed Out |
| Step 1 Total Endurance less Reserve |
Step 2 Fuel Endurance x this Ratio will equal the Time to your PNR from departure airport. |
Step 3 Than Time to PNR x Ground Speed Out will given you the Distance to PNR. |
if all else fails or as a double check.
This formula is handled to understand to help make a quick estimate of roughly where your PNR is.
Given what is at stack it is problem better to use a trial and error method,
by using on your nav computer with the ( frac{Ground Speed}{1 Hour} ) or ( frac{Distance}{Time} )
To workout the distance travelled you need ….
1. Speed, in Knots which is nautical miles per hour.
2. and a Time in minutes.
In this example we have calculated your speed to be 120 Knots and you have been flying for 45 minutes.
On the Wizz wheel, Distance is on the outside and time is always on the inside.
1. Speed of 120kts on the outside (which is Distance travelled in an hour)
2. so, Time is on the inside, line-up the Hour [60 MIns].
Now we have a Distance and Time Ratio setup …
3. Find the time of 45 minutes on the inside (as time is on the inside).
4. Read off the Distance on the outside of 90 nm.
18.22.8 List and explain the uses of: (a) a Mercator projection; (b) a Lambert's conformal projection; (c) the various New Zealand aeronautical charts; (d) the aerodrome charts and associated operational data pages.
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a
18.8.6 State the speed provided by a GNSS and inertial system.
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