Unfamiliarity with the way attitude information is presented in different cockpits is a potentially-lethal problem that emerged decades before the prevalence of Western aircraft in the former Soviet states, and the loss of Aeroflot-Nord 821.
This extract from a US Civil Aeronautics Board report concerns a Beech Bonanza which crashed shortly after departure from an airport in Iowa, whose pilot was "forced to concentrate and rely greatly on the attitude gyro" as the aircraft flew in darkness and poor weather, with an overcast sky and "no definite horizon".
When [the pilot's] instrument training was taken, several aircraft were used and these were all equipped with the conventional type artificial horizon and none with the Sperry Attitude Gyro such as was installed in [the Bonanza]. These two instruments differ greatly in their pictorial display.
It explains that the conventional instrument featured a moving 'aircraft' bar against a fixed horizon, while the Sperry gyro used a moving horizon behind a fixed 'aircraft'.
The pitch display of this instrument is the reverse of the instrument [the pilot] was accustomed to; therefore, he could have become confused and thought that he was making a climbing turn when in reality he was making a descending turn.
In an attachment to the report the investigators supplied a special 'safety message' to pilots pointing out the risks, too late for the unfortunate Bonanza pilot, Roger Peterson, killed in the 3 February 1959 crash with his three passengers: Richard Valenzuela, JP Richardson and Charles Hardin - better known as Ritchie Valens, the Big Bopper and, of course, Buddy Holly.
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