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-6- sufficient reference to maintain control of the pitch attitude. With his limited experience the pilot would tend to rely on the attitude gyro which is relatively stable under these conditions.

Service experience with the use of the attitude gyro has clearly indicated confusion among pilots during the transition period or when alternating between conventional and attitude gyros. Since Peterson had received his instrument training a in aircraft equipped with the conventional type artificial horizon, and since this instrument and the attitude gyro are opposite in their pictorial display of the pitch attitude, it is probable that the reverse sensing would at times produce reverse control action. This is especially true of instrument flight conditions requiring a high degree of concentration or requiring multiple function, as would be the case when flying instrument conditions in turbulence without a copilot. The directional gyro was found caged and it is possible that it was never used during the short flight. However, this evidence is not conclusive. If the directional gyro were caged throughout the flight this could only have added to the pilot's confusion.

At night, with an overcast sky, snow falling, no definite horizon, and a proposed flight over a sparsely settled area with an absence of ground lights, a requirement for control of the aircraft solely by reference to flight instruments can be predicated with virtual certainty.

The Board concludes that Pilot Peterson, when a short distance from the airport, was confronted with this situation. Because of fluctuation of the rate instruments caused by gusty winds he would have been forced to concentrate and rely greatly on the attitude gyro, an instrument with which he was not completely familiar. The pitch display of this instrument is the reverse of the instrument he 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. The fact that the aircraft struck the ground in a steep turn but with the nose lowered only slightly, indicates that some control was being effected at the time. The weather briefing supplied to the pilot was seriously inadequate in that it failed to even mention adverse flying conditions which should have been highlighted.

The Board determines that the probable cause of this accident was the pilot's unwise decision to embark on a flight which would necessitate flying solely by instruments when he was not properly certificated or qualified to do so. Contributing factors were serious deficiencies in the weather briefing, and the pilot's unfamiliarity with the instrument which determines the attitude of the aircraft.

BY THE CIVIL AERONAUTICS BOARD:

NOTE: See attachment entitled "Safety Message for Pilots."

USCOMM.—DC