how to calculate three point Point of No return air navigation questions?

Question

These are the questions asked in the pilots license examination by the DGCA in India. You may explain with any example

Answer 1

A method that is easy (after you've done it a coulpe of times), accurate and will work for any type of PNR (3 eng, 2 eng, Depress) and at any "out" condition is as follows:

1. At a suitable point after TOPC, ie the START POINT, note the distance from the departure airfield (assuming that's the one you'll go back to if you have a problem). Note the fuel on board.

2. From the fuel on board, subtract the Fixed Reserve (30 minutes Depressurised PNR, 10 minutes Engine Failure PNR).

3. From the remaining fuel, divide by 110% for an Engine Failure PNR. To be super technical, we could assume that there would be little variable reserve needed for the OUT segment to the PNR, but to err on the conservative side, we take off 10% for the whole of the remaining fuel.

4. Calculate the SGR OUT by dividing the Fuel Flow OUT by the Groundspeed OUT.

5. Calculate the SGR BACK by dividing the Fuel Flow BACK by the Groundspeed BACK. This will be at the BACK configuration.

6. Calculate the fuel required from the START POINT back to the ORIGIN (at the SGR BACK).

7. Subtract the fuel required from the START POINT back to ORIGIN from the fuel available.

8. Divide the fuel remaining by the sum of the SGR OUT and the SGR BACK. This is the distance from the START POINT to the PNR. Add the distance from the START POINT to ORIGIN and that's the PNR from the ORIGIN in miles.

Answer 2

This sounds like what is known as an ETP (Equal Time Point ) or "Wet Footprint" question. The answer is basically as follows:

ETP=(D*GSret)/(GSret+GSfwd)

Where:
D= total distance for the flight
GSret=ground speed from the ETP back to the origin (GS return)
GSfwd=Ground speed from the ETP to the destination (GS moving forward at the ETP before you turn around to return)

The solution gets a lot more complicated if there is a wind shift involved. Please repost if you need additional info

Answer 3

The point of no return is simply the point at which you no longer have sufficient fuel to return to your point of departure. A very rough guesstimate would be to calculate the range on one-half fuel load but this must be adjusted for winds aloft and any required reserve for an alternate field.

Answer 4

In the aircraft owners manual it gives you the consumption rate of fuel for a time like say one min. etc at a given RPM for that crafts engine.
This rate will vary for any given aircraft but it will be close enough that you can calculate distance, by using information on wind speed etc, and ground speed that is easy to calculate according to your weight capacity. As you know on any given flight plan your ground speed can vary because of wind speed, cross winds, and such.
When you plan your cross country trip you have with it all the distances involved from one leg of flight to another.
Using your fuel consumption, find how far you can go total on your fuel supply and Divide it by 2. Now find a mark on your flight plan that fits that distance and mark it as from this point on I can not go back not enough fuel.

You have available the maps, charts, weather service and others along with your tools like speed calculator and such to find out any info you need to know.
Just learn to use all of them and you will be OK.

Answer 5

I think you are studying for the exams. If that is the case go back into your books and work it out. Pay attention in class. I don't think you will pass any exams asking for answeres in this forum.

Answer 6

Departure ariport, possibly.
More accurately, no return to an airport suitable for landing.