H.A.L.O.
High Altitude/Low opening (HALO) jumping from upwards of 36,000
feet on oxygen. At that altitude the tempurature is subzero, and it
is common for your goggles to freeze and shatter, and your eyeballs
to freeze shut. This type of jumping is very dangerous because of
the effects of hypoxia - lack of oxygen. Hypoxia can cause a man to
lose consiousness in an instance with no prior warning. One second
you are checking your altimiter, the next you are out. bam - no
warning. If this happens while in freefall it can lead to sudden
deceleration trauma - you guessed it - death upon impact. Equipment
common to all freefall ops are the Ram AIr, altimeter, FF2
(automatic pressure activated rip cord pulling device - it is
supposed to pop your chute if you don't when you descend past a
pre-set altitude). Hook knife, helmet and goggles, gloves, oxygen
bottle and mask (if jumping over 12,000 feet) and a sturdy pair of
jump boots are a must for ankle support.
H.A.H.O.
High Altitude/High Opening jumping is an extremely difficult form
of insertion which requires a tremendous amount of training as an
individual and team. A typical HAHO profile has a squad jumping out
of either a commercial aircraft or military craft with a commercial
IFF signature in the normal air traffic lanes so as to not raise
suspicion. The jumpers will exit the aircraft at a high altitude -
say 30,000 feet, and deploy their parachutes in ten to fifteen
seconds at an altitude of 27,000 feet or so. The squad will form up
in a stack in the air, with the low jumper setting the course and
acting as the guide. The squad will fly upwards of thirty or more
miles in formation, using a compass, way points and terrain
features to navigate to their targeted landing zone. Along the way,
the navigator must correct his course for changes in winds speed
and direction, making for a tricky navigation problem. The only
thing more difficult than navigating while flying a Ram-Air is
navigating with an attack board underwater. Nonetheless, HAHO free
fall operations can get SEALs where they want to be clandestinely
and ready to wreak havoc!
Abstract from http://www.navyseals.com/equip/air.html
