View Single Post
  #4  
Old April 18th 08, 11:22 AM posted to rec.aviation.piloting
WingFlaps
external usenet poster
 
Posts: 621
Default Should I be scared -- C172 over Gross

On Apr 18, 6:56*pm, Frank Olson
wrote:
WingFlaps wrote:
On Apr 18, 4:02 pm, Frank Olson
wrote:
tman wrote:
Flown C172's for quite a while, and never had anybody in the back.
Now I'm planning on quite a trip, with 2 pax and luggage.
When I fill the fuel to the *tabs*, calc everyone's weight honestly and
consider baggage -- I'm 75 lbs over the 2450 gross on departure. *Maybe
100 over gross if I assume a "lie about weight" factor or some
inaccuracy with filling the tanks. *Now I'm scratching my head about
just how risky this is. *I know (others) have pushed over gross in these
planes way more under worse conditions, and have almost always gotten
away with it. *I'm inclined to just do it, and be cognizant that it will
perform differently, i.e. don't expect the same picture on climbout that
you would when solo.
Risky? *Or just roundoff error on the weight? *Here are some other factors:
This is the 160HP C172, standard.
Departure runway is 5000'.
No steep terrain to climb out of.
Plenty of alternates along with the way with 3000 runways.
Not particularly hot, humid, or high. *50 degrees at 1000 MSL for
departure or any point of landing.
I'm figuring I'm 3% over gross, causing most of my V speeds to increase
1.5%, so say -- instead of flying short final at 65 knots, I'd fly at 66
knots... OK wait I can't hold airspeed to +/- 1 knot on most days anyways.
I'm thinking through many of the factors, and it is only a "little" over
gross, only on the first hour or so of the trip. *What else should I be
aware of? *Am I dangerous?
T
I worked for a large insurance adjusting firm in Canada many years ago.
* I had to hand deliver a denial of claim letter to a small time
operator whose stock in trade was to hire low time commercial pilots and
bully them into ignoring the gross weight limits. *The aircraft in
question was a float equipped Helio Courier. *The right wing departed
the airframe during an approach to landing. *A fisherman witnessed the
whole thing. *It crashed into the trees. *Four people (including the 19
year old pilot) were killed. *We were able to determine that the
aircraft was 350 pounds over it's gross weight limit at the time of the
crash. *We calculated it was about 500 hundred ponds OG when it took
off. *The company went out of business shortly thereafter. *Their
insurance contract was cancelled "ab initio" (a Lloyd's term for "at
inception" or "from the beginning") and once that happens good luck
trying to find another provider. *Don't fly *any* aircraft over its
gross weight limit. *The pilot was held personally responsible for the
accident and had he survived, would have faced a number of liability claims.- Hide quoted text -


There seems to be an incredible amount of ignorance about what MTOW
means for the airframe structure. There is _no way_ being 350 lbs over
can tear a wing off as you describe. The aircraft is supposed to reach
it's structural limit before such failure (e.g. 4.4g = thousands of
pounds over MTOW). If the accident happened as you say I'd look very
hard at the maintenence and airframe corrosion. The problem with
moderate overloading is not structural but rather poor climb
performance and COG. For example, slap some floats on many planes and
the MTOW is immediately increased. How can that be- same engine and
wings and yet the plane can suddenly fly a higher MTOW. If half the
poasters here were correct youd expect crashes all over the place.
Commercial airlines regularaly go over MTOW because they don't weigh
the passengers. Think about it please!


Cheers


You are correct. *Corrosion was a factor in the accident, but it was
only considered as "contributing". *


I hope you are suitably impressed at my insight.

You're dealing with two different
things here. *If you read your insurance contract it has strict
provisions when it comes to the way you operate your aircraft.
Operating it with no C of A, or in such a manner that could violate the
C of A, leaves the provider recourse to a whole host of legal actions
(up to and including cancellation of your contract). *And then there's
"subrogation".


The C of A on my aircraft is non terminating. What does that mean?


Heavy metal pilots know exactly what their aircraft weigh before they're
pushed back from the gate.


There we disagree. They may know cargo and baggage and fuel but not
meat.

Cheers