A1
Range of NDB over water = 3 X Square root ( Transmission power in watts )
1 KW = 1000 watts
10 KW = 10,000 watts
Range = 3 X Square root ( 10,000 )
= 3 X 100
= 300 nm
Not sure how the answer is 100nm
The closest answer would be 94 nm for 1 KW NDB ( 3 X SQ root {1000} )
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A2
The time during which no usable signal will be received is the time flown over the cone of confusion
For this we have to calculate the cone of confusion at 30,000 feet
The cone of confusion for a VOR is 50 degrees to either side (left and right ) of a VOR
30,000 feet is the vertical distance . We can convert this into nm by dividing by 6080
30,000/6080 = 4.934nm = Vertical Distance from the VOR
Tan ( 50 ) = Horizontal distance / Vertical distance
horizontal distance = tan50 X Vertical distance
= tan50 X 4.934
= 5.88nm
Now this is the radius of the cone of confusion . To get the diameter we multiply by 2
5.88 X 2 = 11.76
So when the aircraft travels through the diameter of the cone of confusion no signal be received .
Now we have to calculate the time taken to fly 11.76 nm at a GS of 300 knots
Time = 11.76 / 300 = 2 minutes and 21 seconds
The closest answer is 2.25 mintues
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A3
For this question i dont think you seem to have the whole question with you
The question actually is what is the Deviation shown on a 5 dot CDI indicator when the aircraft in on the edge of an airway (10nm wide )and 100nm from a VOR
If an airway is 10nm that means the aircraft is 5nm from the centreline on the airway ( since its on the edge )
Now we use the 1:60 rule to calculate the angle subtended from the VOR
Angle = ( S/R ) X 60
= ( 5 / 100 ) X 60
= 3 degree
A CDI show a max of 10 degrees
So on a 5 dot indicator , 1 dot = 10/5 = 2 degrees
So how many dots = 3 degree
The answer is 3/2 = 1.5 dots
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A4
This questions is simple . Just use the 1:60 rule
Angle = ( S / R ) X 60
( Angle X R ) / 60 = S
( 1 X 200 ) / 60
Therefore S = 3.33 nm
The closest answer is 3.5nm
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I am not sure about the first answer
The 2nd answer is much easier to understand if you draw them first
I hope you understood the methods explained