Jumpmasters are the expert paratroopers in an airborne unit who train and teach the military techniques for jumping from airplanes.
Jumpmasters are easily identifiable in Army formations by their ability to earn an advanced rating for their Parachutist Badge.
The Jumpmaster wears this knife in case a jumper somehow becomes entangled during the exiting process, becoming a towed parachutist, and must be immediately cut free.
If radio contact is possible, the DZSTL will pass surface wind information and limited weather observations to inbound aircraft and units, as required.
When radio contact is not possible, the DZSTL must ensure DZ markings are properly displayed as pre-briefed to convey the appropriate message to aircrews.
He also ensures the DZ is clear of all personnel and equipment not required to support the airdrop no later than 10 minutes before the estimated time over target.
The DZSTL is responsible for the operation of all visual acquisition aids and electronic equipment, such as smoke, flares, signal lights, and radios.
The difference in the required duties of the DZSO as opposed to the DZSTL is tied to whether or not the mission is supported by an Air Force Combat Control Team.