Two seater CG question

On Tuesday, June 3, 2014 6:52:29 PM UTC-6, Karl Striedieck wrote:
Anyone know why the Duo (and supposedly other Doppelsetzers) have the same minimum front seat weight with or without a person in the back seat?



The rear seat moment arm has about 1/4th the effect compared to the front, so I would think a 200 pounder in the rear would reduce the front min weight by 50 pounds - nicht wahr?



Maybe the numbers are based on a super cautious approach for situations like an instructor jumping out when the student solos and forgetting to recompute the cg?

I believe it specified in JAR-22 as the design minimum-minimum seat load, just as 110kg was specified as the design minimum-maximum seat load. Not based on CG limits. I recall a conversation about flying a G-103 from the rear seat with the front seat empty and still being with CG limits.

That said, you can read all about it in CS-22 (formerly JAR-22)

http://easa.europa.eu/system/files/d...20Amdt%202.pdf

or from the link here
http://easa.europa.eu/document-libra...22-amendment-2

See paras 22.21 through 22.31.

Frank Whiteley