What is the maximum airspeed loss threshold that prohibits takeoff or approach if reported below 1,000' AGL by a similar sized aircraft?

• A. 10 kts
• B. 15 kts
• C. 20 kts
• D. 25 kts

Answer: (B)

When another aircraft of similar size reports a loss of airspeed below 1,000 feet AGL, you need a clear safety margin to decide whether it’s safe to continue takeoff or approach. A loss of 15 knots is enough to significantly affect energy, response time, and the ability to recover if you need to execute a go-around or adjust flight path in a tight, low-altitude environment. That level of loss below 1,000 feet AGL presents a real risk to safe stability and separation, so the guideline prohibits taking off or continuing an approach if such a report is received.

Smaller or larger losses don’t align with the same safety margin: 10 knots is too small a signal for the risk at this critical altitude, while 20 or 25 knots would be overly restrictive and unnecessary in many situations. The 15-knot threshold strikes a practical balance, providing enough warning to protect safety without needlessly grounding operations.