S
SeniorOfficerPotnky
Guest
The light poles are designed to 'pop" out of the ground, as you put it.
Quoted from Pentagonresearch.com:
Quoted from Pentagonresearch.com:
These poles are designed to break away because of the helipad at the Pentagon.Pentagon Research said:1) The poles were breakaway style on a 18 inch transformer style base. This means that at 23 inches off the ground the pole would be broken by a Volkswagen Rabbit traveling 20 mph.
2) The poles themselves were 27.66 feet high with a weight of approximately 175 pounds.
3) The truss style mast arms were 8 foot long with a rise that brought the pole height up to 30 feet. The mast arm weighs between 15-20 pounds.
4) The lamp head weighs approximately 70 pounds.
5) The aluminum on the poles was .188 of an inch thick. The pole was 8 inches in diameter at the base and 4.5 inches in diameter at the top.
This limited damage factor is why the FAA requires these type of poles in the "safety zones" around airports and helipads. They recognize that this type of pole minimizes damage to aircraft, "FAA regulation requires any structure located within 250 feet of runway centerline has to be frangible, which means the structure needs to break away when hit by an aircraft to minimize damages to the aircraft and its pilot."