Hi,
Personally I do not think the AF447 accident has any relation (or could be explained) by trigonometry .. geometry or other formulas .. academic or by the curvature of THS
The accident was related to the actions of the pilot(s)
This aircraft was built according to specifications and apparently he has met these requirements since it was authorized to make commercial flights.
And since the AF447 accident he continue to perform commercial flights
This aircraft is equipped with up to date flight and navigation aids
So .. it indicates to pilots (in the case of 447) that there may stall ... or if this warning is not followed by appropriate reactions of the pilots .. he will warn that the aircraft is experiencing stall
The pilot did not have appropriate responses to deal with the event and did not have appropriate responses to correct his first mistake
The aircraft systems were all put in place to prevent the pilot from his mistake
The stall alarm has been running for 54 seconds continuously
The artificial horizon presented a large blue area
The altimeter showed a rapid loss of altitude
The origin of the event is the icing three pitot probes at the same time (same manufacturer .. same type .. no luck for redundancy)
There was also 3 pilots icing (brain icing) ....
The three pilots, however, were of different types .. but of the same brand (AF)
Even there .. redundancy has not worked ...