Jamman,
Actually, the guidance was from a Fort Worth ACO Engineer and was accepted by the Atlanta ACO recently when I reviewed some data for approval in mid-2003.
A Cd of 1.0 would be the most UNCONSERVATIVE value to use on internal venting but most CONSERVATIVE on the damage opening size so I...
Just to throw in a side note regarding vent opening coefficients (often called "discharge coefficients"), the FAA recently directed me to an Advisory Circular that clearly states the FAA will accept .50 for a coefficient for a "hole caused by failure of the fuselage" and .75 for a "hole caused...