found entangled in the broker Teadfig edge of the DC3's right. Nothing was found to indicate malfunctioning of either plane prior to the collision.
Several persons who saw the two planes just before they collided testified that both were in straight, level, the airliner heading west and the Boeing heading south. They said they could see the planes distinctly although there was a haze and the sky was they could see the overcast.
Captain Smith, who was piloting from the left seat, stated that after he Leveled off at 2000 feet indicated altitude, to Joliet in anticipation of shortly going on instruments and that his attention was divided equally inside and outside the cockpit. They had just crossed the southwest leg of the Chicago range and were on a heading of 260°:when the Kirst Officer yelled, "Look out!" The captain said he immediately started a left turn because he felt that any danger would be coming from the First Officer's side on the right. At the same time he caught a glimpse of the other plane at the instant of impact. First Officer Reier stated that been looking at ground objects and that when he first saw the other aircraft it was approaching from his right at a 45° angle at a diving altitude. He said he called out and as the Captain lifted the right wing of the DO3 the other plane passed beneath it and he heard the crash almost simultaneously. Both Smith and Reier stated that the weather was hazy with visibility 2-4, miles variable and that ground objects were plainly visible. Neither would estimate the ceiling although both stated they were beneath it at their altitude of 1300 feet above the ground (2000 feet indicated).
The nearest weather reporting station to the scene of the accident was at the Chicago Municipal Airport; 7 miles northeast. At that station the ceiling was unlimited, high overcast, thin scattered clouds at 1200 feet, visibility 11 1/2 miles and light smoke. It is known that the amount of stratus clouds increased to the southwest and it was overcast at the scene of the accident; thus pilot vision could not have been impaired by the sun. It is estimated from all information available that the ceiling was 1500 to 2000 feet.
The wind was from the cast-southeast which would carry smoke into the area from nearby industrial sections. Stratus clouds were located at the base of a temperature inversion. As smoke would tend to accumulate in the upper portion of the layer below this inversion it is highly probable that horizontal visibility decreases with elevation. Although no accurate estimation of the visibility at 1300 feet can be siren, it must have been considerably less than at ground level.
CONCLUSIONS AND FINDINGS
This accident occurred about 7 miles southwest of the Chicago Municipal Airport, and within the 10-mile approach zone. Civil Air Regulation required that in such an area contact fight be conducted at not less than
-2-
