If you are at FL 300 and 60 DME, required to cross at 10 DME at 5000 ft with a ground speed of 300 NM/HR, what should your VSI be?

To determine the vertical speed indicator (VSI) that you need to maintain in order to cross at 10 DME at 5000 feet while descending from FL 300 (30,000 feet), we first need to calculate the altitude to be lost and the time available to descend.

You start at 30,000 feet and need to be at 5,000 feet when you cross at 10 DME:

1. Calculate the altitude loss:

• 30,000 feet - 5,000 feet = 25,000 feet.

2. Calculate the horizontal distance to descend:

• You are currently at 60 DME and need to be at 10 DME, which means you have 50 nautical miles to work with.

3. Calculate the time to descend:

• With a ground speed of 300 NM/HR, the time to cover 50 NM is:

• Time = Distance / Speed = 50 NM / 300 NM/HR = 1/6 hour, or 10 minutes.

4. Convert time into minutes for vertical speed calculation:

• 10 minutes = 600 seconds.

5. **Calculate the