What is the phraseology used for informing pilots about an unsafe runway?

The phraseology "Runway # closed/unsafe. At own risk" effectively communicates the critical information that the runway is either closed or deemed unsafe for operations. By including "At own risk," it clearly indicates that pilots should proceed with extreme caution if they choose to use the runway despite the warnings. This phraseology emphasizes the potential dangers and allows pilots to make informed decisions based on their assessment of the situation.

Clarity is paramount in air traffic control communications, especially regarding safety. This phrase makes it clear what action the pilot may choose to take while highlighting the inherent risks involved. The use of terms such as "closed" or "unsafe" directly conveys the state of the runway, ensuring that pilots have a clear understanding of the runway's condition.

The other options typically either lack a similar clear directive regarding risk or do not convey the same level of urgency or caution necessary for the situation. Thus, the chosen phraseology aligns well with standard practices for communicating safety concerns in aviation.