Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Tue, 24 Sep 2002 10:38:47 -0400
Message-ID: <redirect-1770237@logan.com>
From: JPKleber@aol.com
Subject: LEG2 Shoulder Harness Installation
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit

The FAA has conducted extensive research into the area of occupant safety and 
occupant restraint in aircraft.  The Civil Aero-Medical Institute (CAMI) in 
Oklahoma City is charged with  this responsibility.  Their findings and 
recommendations are available to everyone in Advisory Circular AC21-34.  This 
can be downloaded from the  www.faa.gov website.

To prevent spinal compression, and still provide the occupant with maximum 
restraint, AC21-34 recommends a shoulder harness installation angle between 
-5 degrees and +30 degrees.  It states: "the 30 degree elevation angle is the 
maximum angle which will provide effective restraint by the shoulder belt."  
The rationale for this conclusion is provided in the Advisory Circular;  in 
short, an excessive angle creates  excessive loads (on the airframe and 
harness webbing), and permits excessive motion of the occupant (resulting in 
head and neck injuries).

Now, back to the Legacy ........ take a moment to measure the angle of the 
shoulder harness from the factory-installed hard points in your Legacy.  What 
angle do you come up with?   On my Legacy, the angle is over 40 degrees.  
However, if the attach point is moved aft to just in front of the baggage 
wall bulkhead, the angle is reduced to approximately 17 degrees which falls 
well into the optimum range.

There are several other geometry considerations when installing seat belts 
and shoulder harnesses.  AC21-34 is an excellent publication devoted to this 
topic.

John Kleber
N83JK   LEG2/G