A little note regarding the 737-200. Followig was published many years ago:
Since 1970 there have been a number of reports by operators of B-737 aircraft who have experienced an aircraft pitchup or rolloff immediately after takeoff in weather conditions which were conducive to the formation of ice or frost on the wing leading edges.
As a result of incidents involving B-737 aircraft which experienced a sudden
roll after takeoff, The Boeing Co. on October 24, 1974, issued Operations Manual Bulletin
No. 74-8.
The continuation of reports of pitchup/rolloff occurrences prompted The
Boeing Co. to examine further the B-737 aircraft sensitivity to leading, edge contamination. In 1977 plans were formulated for wind tunnel and flight tests. Even before conducting these tests, The Boeing Co. on February 23, 1979, issued Operations Manual Bulletin 79-2 to advise flightcrews of a possible inadvertent pitchup/rolloff after takeoff due to ice accumulation on leading edge devices
As part of its investigation of the reported incidents, The Boeing Co. flight
tested a B-737-200 advanced airplane in the fall of 1980 to quantify the aerodynamic effects of contaminated leading edge slats. The leading edge slats were coated with an epoxy potting compound and the surface was roughened with a paint roller to simulate a coating with corn ice. A series of stalls was conducted with flaps up, and at flap positions of 1, 15, and 40. The stall characteristics with both symmetric and asymmetric leading
edge contaminations were characterized by a very apparent pitchup, yaw rate, and rolloff. These characteristics were more pronounced at flap settings less than 5 when the slats were sealed, that is, when there was no gap between the leading edge slat and the basic
wing such as that which occurs when the slats are fully extended coincident with flap settings between 10 and 40. The Boeing Co. concluded that takeoffs are executed during suspected icing conditions or adverse weather conditions, sound operational techniques must be employed.
The Boeing Co. internal memoranda showed that it was considering an engineering change to the wing thermal anti-ice system to permit the use of that system on the ground to assure a clear leading edge.
For those interested, more details can be found in the Air Florida Flight 90 accident report.