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Old 30th Sep 2010, 18:12
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Pugachev Cobra
 
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Arrow IV W&B CG Too Forward

Hello PPRuners...

I'm getting concerned with a situation with a weight and balance calculation of a Piper Arrow IV.

The CG limits are 85 to 93 inches, and starting from 2400lbs up to 2900lbs, the forward limit gets closer to the aft limit, with MTOW having 89 to 93 in of buffer.

The aircraft in question has a BOW of 1808lbs since its last weight and cg determination, and the CG was at 79.96 inches.

I found it strange that the BOW of the aircraft had the CG so off the envelope, since the chart just went back to 81.8 in. The envelope starts at 85, but the cg is off the charts!

Still, I redid several times with different calculations as to how the aircraft is normally operated (full tank, half tanks, 3 POB, 2 POB, no baggage, etc.)

Everytime the CG is off limits, too forward.

Now, the common conception (what I think is a misconception) around here, is a culture where people disregard doing W&B for small aircraft, that is inaccurate, etc. etc. etc., and that a few inches off the envelope doesn't do harm, you just rotate with a little higher airspeed and such...

My question is, is it 3 or 4 inches forward of the cg limit (if the forward limit is 85 inches, I'm talking here 81, 82 inches) not to worry about? Is it not that a bigger deal?

Or are we seeing here a future accident?

What worries me more is that, with fuel burn the CG moves further forward, so in landings it's gonna mean trouble. People constantly tell me that the roundout to touchdown the aircraft has a heavier nose and it's hard to pull, to trim up, etc. But that does seem normal with some aircraft.

Should I worry about this or not?

All inputs are appreciated.

If a CG more forward than the certificated limit is acceptable and the aircraft has been flying for a long time without any incident, how does one measure the actual true value of the CG limits of light aircraft's AFM/POH?

How do you convince the pilots and operatores of this small aircraft to respect the manual and the W&B procedures, when they always operate out of the envelope and nothing dangerous ever happens?

Thank you in advance!
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