[TowerTalk] Fall Arrest Post- fall response, A Medical Emergency

[Pat Barthelow]

A Google search using "Fall-Arrest" search term brings up a wealth of 
information from industry and research studies.  One study conducted by 
Wright Patterson AFB suspended subjects in body harnesses a foot or so off 
the ground while the subjects were fully medically instrumented, for heart 
rate, BP, etc..

see: http://www.cdc.gov/elcosh/docs/d0500/d000551/d000551.html

The test was terminated at each iteration when subjects mentioned feeling 
symptoms deemed by medical doctors as dangerous, or if the physicians 
monitoring of vital signs, deemed them to be of a nature to terminate the 
test.  Most tests were terminated in minutes.  One subject lost 
consciousness.

Earler in the website with this research data, a case history was recounted 
of a worker falling from a rail car, equipped with a designed-for fall 
arrest system.  Persons on scene communicated with the worker, assuring that 
rescue resources had been called. The person responded...Once the fall 
happened, the worker was suspended rather high in the air, and 911 response 
resources were hailed, and it was realized that the situation demanded 
specialists to lower him to the ground.
He became unconscious before rescue resources arrived, and when reached by 
rescuers had already died.

It was flat stated at the end of the article that a fall arrest system that 
saves the worker suspended off the ground IS A MEDICAL EMERGENCY, requiring 
quick response to lower the person in the safety harness to the ground.....

I guess the devil is in the details of the suspension harness design...I 
Jumped out of "perfectly good airplanes" for 20 some years, and in some 
cases had long rides down in the parachute harness.  The harness was built 
to order, custom sized to my measurements.

Usually, a 2500 ft opening, was accompanied by a 2-1/2 minute ride down.  
Sometimes I went for a high opening  (10,000 ft) for a 'cross country'.. 
really beautiful ride.. 10-15 minutes in the harness, I dont recall 
discomfort, but the harness has well designed padding under the 3 snaps 
(legs, chest) that held me in the harness, and the webbing was just shy of 
3" wide.

In the course of this 'other' hobby, with 'normal' parachute openings, in 
the old days of round parachutes, 3-4 Gs were normal opening forces. Time 
from ripcord pull to 10 mph, is about 3-4  seconds.   The perception of the 
opening shock also varied widely depending on your body position at the time 
of deployment.  Suspension points on the harness were right at your 
shouulders. A head low, or (heaven forbid) a vertical head down opening was 
quite harder, than the preferred horizontal position depoyment, partly due 
to higher speeds head down, and partly due to the pivoting action once 
deceleration forces are applied to the shoulder attachments of the harness.

A couple of reserve (second, emergency parachute) rides with FAR faster 
openings,  I STILL remember, Bring you from about 200 ft per second to 20 ft 
per second in  about .75 second, and HURT. [not nearly as much as the 
alternative]  Experts say that reserve openings in the old days  were 
sometimes 10 G.  Today, both main and reserve openings are MUCH Milder with 
square parachutes.

By the way, speaking of Gs, I can send  out a  great video of a guest 
passenger in a military jet, losing consciousness 3 times ...in mere seconds 
each time, while experiencing Hi (probably 6-8)  G maneuvers.  I have a wave 
file, have to figure out how to post it to the net.

Do the google search....it is great reading...


73, DX, de Pat AA6EG aa6eg at hotmail.com;
                  Skype:  Sparky599