Continued VFR into IMC is when an aircraft operating under visual flight rules intentionally or unintentionally enters into instrument meteorological conditions.
[5] In the 180—Degree Turn Experiment conducted in 1954 by the University of Illinois, in order to establish a baseline for the effectiveness of instrument training, twenty non-instrument pilots flew from VFR into simulated IMC; after entry, all of them eventually reached a dangerous flight condition or attitude[a] over a period ranging from 20 to 480 seconds.
)[3] Nonetheless, the original 1954 study was simulating an aircraft the subjects had little to no experience with, was intentionally chosen to be the most difficult to succeed in, only provided a partial instrument panel, and the subjects themselves were chosen because of their lack of training and experience.
[3][6] In addition, the "178 seconds" average time was extracted from the preliminary evaluation; after training for a standardized procedure to exit IMC, each student pilot was tested three times, and 59 of the 60 resulting simulated flights successfully resulted in a controlled descent out of the cloud deck without reaching a dangerous condition.
[8] As a result, AOPA's and the FAA's 178 second claim is thought of by many as significantly mischaracterizing the reality of flight in 1954, and does not take into account modern planes, instruments, and training standards.