Area Control Services

An aircraft is flying at FL 150 in class D airspace, while another aircraft at FL 140 has been cleared to descend to FL 70. Given the severe turbulence in the area, when can a clearance to descend to FL 140 or below be anticipated?

• AWhen the other aircraft has reported that it has left FL 140
• BWhen the other aircraft has reported that it has reached FL 70
• CWhen the other aircraft has reported that it has descended through FL 130

What is the minimum longitudinal separation time between aircraft at the same cruising level, where navigation aids allow for frequent position and speed updates, and the preceding aircraft is flying at a true airspeed that is at least 40 knots faster than the following aircraft?

• A5 minutes
• B3 minutes
• C10 minutes

What is the minimum longitudinal separation time between aircraft at the same cruising level, where navigation aids allow for frequent position and speed determination, and the preceding aircraft is flying at a true airspeed that is at least 20 knots faster than the following aircraft?

• A15 minutes
• B10 minutes
• C5 minutes