Flight computers are still used today in practical situations. With the electronic flight computer taking the place of the old school manual E6B which is still used for instruction at many flight schools today.
It is good practice to learn the basics of the E6B and can be used as a quick reference.
Trivia about the E6B
The E6B was designed by U.S. Navy Lieutenant Philip Dalton in the late 1930’s. The name of the device actually comes from its part number from the U.S. Army Air Corps.
Sides of the E6B
The E6B has two sides:
Calculator side (front)
Wind side (back)
Calculator side - is used to calculate main different things such as: time (minutes and hours), distance, fuel burn, density altitude and much more.
Wind side - Is used to determine the effect of wind on the airplane, such as: heading and ground speed.
How to find Ground Speed and True Heading
First, we need not find the groundspeed before we can solve any other question. To do this we need to use the wind side of the E6B.
For this example, we will use the information flying from Riverside (KRAL) to Ramona (KRNM):
Winds - from 290° at 21kts
Course - 154°
True airspeed - 95kts
To find the ground speed using the information above we need do a few steps. If you forget how to do these the steps are printed at the top of the slider card.
First, set the wind direction of 290° under the “True Index” pointer.
Mark a dot with a pencil for the wind speed at 21kts straight up from the center grommet.
Rotate to set the course of 154° under the “True Index” pointer.
Slide the card until the pencil mark (red dot on figure below) is on the true airspeed line of 95kts.
Read the ground speed under the center grommet.
Other Information needed: Magnetic Heading of 145°
Answer: 109kts ground speed, read under center grommet.
How to use the Flight Computer side
Time and Distance:
First, set the pointer (black triangle) to the ground speed (GS) of 109kts located on the outer ring.
Then find the distance, also located on the outer ring. Its 60.8NM between Riverside and Ramona airports.
The time is found on the middle circle in minutes.
Answer: 33.5mins
Fuel Burn:
To find the fuel burn for any type of aircraft, we need to find the gallons per hour (GPH) in the Performance section of the aircrafts POH. For this lesson we will use the two listed below.
Cessna 172P has a fuel consumption of 7.4 GPH at cruise.
Piper Cherokee 180 has a fuel consumption of 8.8 GPH at 75% power at cruise.
For this example, we will use the C-172 GPH information.
Question – How much fuel is required if consuming 7.4 GPH over a 33.5 minute flight?
Set the pointer (black triangle) on 7.4 GPH
Then find the time located on the middle ring, from earlier.
Lastly, the fuel consumption is read on the outer ring.
Answer: 4.14 gals.
References:
E6B instruction booklet
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