# CIESE -Navigational Vectors - Lesson #8

Lesson #7 |
Estimating Arrival Time |
Test Flight |

One of the most common questions travelers have is "When will I get there?" A pilot can estimate the time of arrival of the flight by knowing the ground speed and distance to the arrival city. The distance between two cities can be estimated by maps but how does the pilot actually determine the ground speed?

Inside the cockpit, the pilot can read the air speed indicator and the heading indicator to get both of these values. By knowing the air speed, directional heading, and the wind velocity at the plane's altitude the pilot can determine the ground speed. In this lesson, you will predict the arrival time of an in-flight plane based on an assumed air speed.

**A) Flight Data Summary**

Use the flight data and information calculated in Lesson 7. Assume that the plane runs into turbulence and the pilot decides to reduce the air speed by 25% but stays on the same course heading. Record the following information:

- Air speed (km/h) and directional heading (degrees) [from Lesson 7]
- Reduced air speed (km/h) and directional heading (degrees)
- Wind speed (km/h) and directional heading (degrees) [from Lesson 7]

**B) Determine Ground Speed**

On a piece of paper, place a dot to represent the plane's current location. Draw (to scale) the reduced air speed vector on this diagram. The air speed vector should be located with its tail at the plane's current location. Draw the wind speed vector on the diagram (head to tail with the air speed vector) and at the correct directional heading as measured in degrees. Air speed and wind speed are both component vectors in this diagram. Ground speed is the **resultant** of the air speed and wind speed vectors.

- What is the new resultant ground speed?
- How does this ground speed compare to the original ground speed given on the Flight Tracker flight information page?
- Do your results make sense? Why or why not?

**C) Estimate Arrival Time**

- What is the distance (km) from the plane's current location to the arrival city? This information is given on the Flight Tracker flight information page but you will need to convert to km.
- Use the new ground speed and the distance to the arrival city to calculate the time it will take to reach the arrival city. How long will the flight take to reach its destination?
- What time will it be in the arrival city? Use the local time at the plane's current location and travel time to determine this. (Hint: don't forget to take into account time zones! See
*Reference Materials*if necessary.) - How does this time compare to the original estimated time of arrival from the Flight Tracker flight information page?
- Do your results make sense? Why or why not?

**D) Ready to Become a Pilot?**

- Imagine that the earth rotated in the opposite direction or at a different rate. How might this affect arrival time?
- A pilot for a major airline needs to fly from Newark, New Jersey to Chicago, Illinois in under 3 hours in order to keep to the airline's daily timetable. Assuming that the flight is scheduled to take off NOW, how fast and at what heading does the pilot need to fly the plane in order to keep to the schedule? What will be the estimated time of arrival (ETA) in Chicago? What might help the pilot beat the ETA? Explain.
**(Optional)**