Originally Posted by
Control Eng
I am fully aware that FR24 relies on enthusiast Mode S receivers but am amazed that you seem to consider that this particular programmer was astute enough to be able to write a program that selected just these two particular messages to drop the altitude (while keeping the lat/long from the same squitter) when all his other messages were presented in totality.
Neither you nor I know exactly how FlightRadar24 processes the data it gets from enthusiasts, so I certainly wouldn't make any assumptions about the astuteness, or otherwise, or their programmer(s).
My point is simply that the data we see in those pseudo-messages isn't necessarily what was transmitted by the aircraft verbatim. If you don't believe that, look at the penultimate altitude readout (and others) before it reached FL350 - there is no encoding schema for either Mode C, Mode S or ADS-B that's capable of transmitting an altitude of 34591 feet.