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Their wing strut mounting of that sensor pod causes me a lot of concern... I don't think Cessna ever expected crazy torque loads on strut meant for tension.

In the PyCon video (link posted elsewhere), a questioner asked if they had thought of making the pod able to be controlled during banking to keep the data from being tainted with outlier values. The speaker described that FAA rules determine what can be attached to the airplane so it was better to make the pod dumb and fix the data in post processing. Presumably they built the pod as light as possible to fit under FAA regs.

I'm not sure there is a weight regulation beyond the general guidelines provided by the manufacture which probably don't cover major alterations like this. Its probably more like what they could get the local A&P to sign off on. Part 43 (https://www.law.cornell.edu/cfr/text/14/part-43) is mostly about how the alterations are to be made than dealing with the specifics of the alternation.

Beyond that, its likely is a permanent mark against the air-frame which makes it basically impossible to resell. Including the fact it might have added an additional inspection interval at the strut attachment points. Might even have ended up as an experimental cert due to not conforming to the type any longer.

Also, i'm not so sure there is a lot of formal engineering going into a mod like this on a GA plane. More likely someone has a rough set of parameters for air-frame shear/etc stress and a quick calculation said that the additional stress at 120MPH and landing shock was a small percentage of the total.

I have a cousin that works building fire fighting water bombers. The planes were never engineered for that application as well. They are literally taking these planes and gutting them, add giant pumps and plumbing and other devices some of it literally off the shelves of stores any one of us could use. These devices were never made "for air plane application". But they ultimately have an engineer who decides what is safe and signs off on the design. I have no doubt that this company either has the same or paid the price to have that pod engineered on to the existing limits of the plane.

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