, I happen to have a copy of the C.A.R. under which the C-170 was certified. In short, Cessna had to demonstrate that the aircraft would run, until you are left with the unusable fuel in tanks, (including fuel from the tanks to engine). They did under the five conditions mentioned below:1) Level flight at max cont. power or at design cruising speed.
2) Climb at max continuous power at best angle of climb at minimum weight.
3) Rapid application of power and transition to best rate of climb following a power-off glide
4) Sideslips & skids in level flight climb & glide
5) Maneuvres approved under the utility category.
They also had to establish which maneuvre was the worst case. For sake of discussion only, some of these maneuvers might enable you to run the tanks under the unusable fuel limit, since the previous was established using the worst case …The type certificate data sheet states 37.5 gal. total, 33.5 gal. USEABLE for the C-170 and 42 gal. total, 37 gal. USEABLE for the C-170A& B. It is not clear to me which type was involved. I have two questions: Was there a damage history or major repair done to fuel tanks? Also, is the fuel evenly distributed in each side?
I have a JPEG copy of the C.A.R.’s original text available if anyone is interested. Email me at: ericc170@sympatico.ca
Eric