Weight Limitation for the Front seats of a C172

I was having a chat with an FBO flight instructor yesterday about a
potential student of his who is 6' 4" and pushing 300lbs. As an independent
instructor and big guy myself, he was soliciting my opinion on what which
training aircraft might be appropriate for this student.

I mentioned that a 172 should work provided W&B calculations be conducted to
ensure the aircraft CG isn't too far forward. Then the instructor mentioned
something I'd never heard befo "No, that won't work. The limit of the
Pilot and Co Pilot seats is 400lbs."

"Huh?" I replied.

"Yeah, its a limitation." He reasoned as he showed me the POH W&B graph.
The line to calculate moment stops at 400lbs. His argument was that Cessna
deliberately stops the line at 400, because that is a limit. He stated that
it was FBO policy to abide by this "limitation."

I responded that "Limits" are in the Limitations section, Chapter 2. There
*is* a limitation in the baggage sections, but no such limit in the pilot
seats. If Cessna wanted to institute a pilot station limitation, they would
have explicitly stated it in Chapter 2. I further suggested that if he
didn't want to take my word, he could contact Cessna.

I've never heard this before. Has anyone else? Otherwise, I've broken the
rules on nearly every flight with a passenger or student more than 140lbs

Brad

"Brad Zeigler" wrote in message

"Yeah, its a limitation." He reasoned as he showed me the POH W&B graph.
The line to calculate moment stops at 400lbs.
I've never heard this before. Has anyone else? Otherwise, I've broken
the rules on nearly every flight with a passenger or student more than
140lbs

Yes, we had to live with this when I was instructing in the seventies. As
explained to me, the source limitation is the structural capacity of the
floor structure when subjected to max certificated g loading. But you are
right in that it is mentioned nowhere in the text of the limitations
section.

I hate to disagree without documentation, but I have talked to an engineer
at Cessna who says that the fact that the line ends at 400 pounds is not a
limitation. For seat strength, he referred me to a National Bureau of
Standards website which, after a number of side trips, ends up with a
request that the inquirer pony up some bucks to get the publications
involved.

Bob Gardner

"John Gaquin" wrote in message
...

"Brad Zeigler" wrote in message

"Yeah, its a limitation." He reasoned as he showed me the POH W&B graph.
The line to calculate moment stops at 400lbs.
I've never heard this before. Has anyone else? Otherwise, I've broken
the rules on nearly every flight with a passenger or student more than
140lbs

Yes, we had to live with this when I was instructing in the seventies. As
explained to me, the source limitation is the structural capacity of the
floor structure when subjected to max certificated g loading. But you are
right in that it is mentioned nowhere in the text of the limitations
section.

Cessna also advised me that it was not a limitation, and that it is OK
to extend the graph line - if of course the aircraft remains within
W & B.

Tony
--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE

In article ,
"Bob Gardner" wrote:

I hate to disagree without documentation, but I have talked to an engineer
at Cessna who says that the fact that the line ends at 400 pounds is not a
limitation. For seat strength, he referred me to a National Bureau of
Standards website which, after a number of side trips, ends up with a
request that the inquirer pony up some bucks to get the publications
involved.

Bob Gardner

"John Gaquin" wrote in message
...

"Brad Zeigler" wrote in message

"Yeah, its a limitation." He reasoned as he showed me the POH W&B graph.
The line to calculate moment stops at 400lbs.
I've never heard this before. Has anyone else? Otherwise, I've broken
the rules on nearly every flight with a passenger or student more than
140lbs

Yes, we had to live with this when I was instructing in the seventies. As
explained to me, the source limitation is the structural capacity of the
floor structure when subjected to max certificated g loading. But you are
right in that it is mentioned nowhere in the text of the limitations
section.






--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE