ASA’s FAR/AIM and Flight Crew 2010 Update(87)

b.
* * *

3. The alert is generated by surface radar targets caused by moderate or greater precipitation.
c. * * *
3. One or more of the aircraft involved in the alert is not intend-ing to use a runway (for example, helicopter, pipeline patrol, non-Mode C over.ight, etc.).
SHORT TAKEOFF AND LANDING AIRCRAFT. An aircraft which, at some weight within its approved operating weight, is capable of operating from a runway in compliance with the applicable STOL characteristics, airworthiness, operations, noise, and pollution standards. (See VERTICAL TAKEOFF AND LANDING AIR-CRAFT.)
TRACEABLE PRESSURE STANDARD. The facility station pres-sure instrument, with certi.cation/calibration traceable to the National Institute of Standards and Technology. Traceable pres-sure standards may be mercurial barometers, commissioned ASOS/AWSS or dual transducer AWOS, or portable pressure standards or DASI.