Speed and Distance Calculations Flashcards

What is the minimum en route radar separation standard used by FAA controllers in domestic airspace?

Answer: 5 nautical miles

FAA Order 7110.65 specifies 5 nm as the minimum en route radar separation standard in domestic airspace.

An aircraft at FL280 must descend to 10,000 feet MSL at a rate of 2,000 feet per minute. How long will the descent take?

Answer: 9 minutes

Altitude change: 28,000 – 10,000 = 18,000 ft; 18,000 ÷ 2,000 ft/min = 9 minutes.

An aircraft is 60 nm from the airport flying at 360 knots. ATC issues a speed reduction instruction effective 5 minutes from now. How far from the airport will the aircraft be when the restriction takes effect?

Answer: 30 nm

Distance covered in 5 min: 360 × (5/60) = 30 nm; remaining distance: 60 – 30 = 30 nm.

A controller estimates Aircraft A will reach a reporting fix in 8 minutes and Aircraft B will reach the same fix in 5 minutes. Both aircraft are flying at 300 knots on the same route. What is the current distance separation between them?

Answer: 15 nm

Time difference = 8 – 5 = 3 minutes; at 300 knots, 3 min = 300 × (3/60) = 15 nm separation.

A pilot reports 3 hours of fuel remaining. The destination is 500 nm away. What minimum groundspeed must the pilot maintain to arrive with a 30-minute fuel reserve?

Answer: 200 knots

Usable flight time: 3.0 – 0.5 = 2.5 hours; minimum speed = 500 nm ÷ 2.5 hr = 200 knots.

Two aircraft are heading to the same VOR fix. Aircraft A is 50 nm away at 300 knots; Aircraft B is 60 nm away at 300 knots. What time separation will exist when both aircraft pass the fix?

Answer: 2 minutes

A's ETA: 50 ÷ 300 × 60 = 10 min; B's ETA: 60 ÷ 300 × 60 = 12 min; separation = 12 – 10 = 2 minutes.

At a groundspeed of 360 knots, a controller needs to create a 10-minute delay for an aircraft before it enters congested airspace. Approximately how many extra nautical miles of routing must be added?

Answer: 60 nm

Extra distance = 360 knots × (10/60 hr) = 60 nm of additional routing required.