Nobody can definitively answer this for you except Cessna's 1965/1966 engineering team (the year they made the change), but there are two reasons I can think of:
Because switches are cooler than Johnson bars; or Because everyone else is doing electric flaps.
The handbook is designed:
To help you operate your plane with safety and confidence.
To more fully acquaint you with the basic performance and handling characteristics of the airplane.
To more fully explain your plane's operation than is permissible to set forth in the airplane flight manual.
DescriptionPart NumberPOH CESSNA 172S NAVIII 2004&UP14-02689POH CESSNA 172P 198314-02690POH CESSNA 172P 198414-02691POH CESSNA 172P 198514-02692POH CESSNA 172P 198614-02693POH CESSNA 172Q CUTLASS 198314-02694POH CESSNA 172Q CUTLASS 198414-02695POH CESSNA 172Q CUTLASS 198514-02696POH CESSNA R172E (ARMY 7-41B)14-02637POH CESSNA 172K (ARMY 7-41A)14-02638POH CESSNA FR172J REIMS ROCKET14-02639CESSNA 172 1956 OWNERS MANUAL14-00667CESSNA 172 & SKYHAWK 1957-58 OWNERS MANUAL14-00668CESSNA 172 & SKYHAWK 1959 OWNERS MANUAL14-00669CESSNA 172A 1960 OWNERS MANUAL14-00670CESSNA 172B & SKYHAWK 1961 OWNERS MANUAL14-00694CESSNA 172C & SKYHAWK 1962 OWNERS MANUAL14-00695CESSNA 172 & SKYHAWK 1963 OWNERS MANUAL14-00696CESSNA 172E & SKYHAWK 1964 OWNERS MANUAL14-00763CESSNA 172F & SKYHAWK 1965 OWNERS MANUAL14-00764CESSNA 172G & SKYHAWK 1966 OWNERS MANUAL14-00765CESSNA 172H & SKYHAWK 1967 OWNERS MANUAL14-00766CESSNA 172I & SKYHAWK 1968 OWNERS MANUAL14-00767CESSNA 172K & SKYHAWK 1969 OWNERS MANUAL14-00768CESSNA 172K & SKYHAWK 1970 OWNERS MANUAL14-00769CESSNA 172L & SKYHAWK 1971 OWNERS MANUAL14-00770CESSNA 172L & SKYHAWK 1972 OWNERS MANUAL14-00771CESSNA 172M & SKYHAWK 1973 OWNERS MANUAL14-00772CESSNA 172M & SKYHAWK 1974 OWNERS MANUAL14-00773CESSNA 172M & SKYHAWK 1975 OWNERS MANUAL14-00774POH C172N 1978 FLOATPLANE17-00149POH CESSNA 172S 1998 & UP14-02697CESSNA 172R INFORMATION MANUAL14-02920CESSNA 172R NAVIII INFO MANUAL14-02921CESSNA 182T NAVIII INFO MANUAL14-02922CESSNA 172R/180HP INFO MANUAL14-02923CESSNA 172R 180 HP PRO PILOT CHECKLIST17-00124CESSNA 172R-IM AUS W/ NAV III GLASS PANEL ( GREEN STAR )17-00126CESSNA 172 SIM-BUS W/INTEGRATED AUTOPILOT17-00129CESSNA 172N 1978 POH17-00147CESSNA 172P 1981 PIM17-00160CESSNA 172P 198217-00163CESSNA 172RG 198217-00164CESSNA 172 RG 198517-00167CESSNA 172P 198617-00168
At 0645:44, the pilot asked the controller how far south he had to go to be VFR. I find that the government was negligent in failing to record, properly, the weather conditions in Kalamazoo and that this negligence was a proximate cause of the accident. After initially reporting that it was clear, at 0646:53, the Kalamazoo controller called to say that the weather was "getting down" and he was going to call it two miles. In the first place, if the weather in Kalamazoo had been recorded properly, the Grand Rapids controller would not have initially assumed that Kalamazoo was VFR, and prudently would have determined the nearest VFR airport earlier. Secondly, she never did give a direct response to the pilot's request to know how far south he had to go. Thirdly, she did not tell him the exact weather conditions at Kalamazoo, and the differences between Kalamazoo and Grand Rapids. If, indeed, the pilot remains ultimately responsible for the safe operation of his aircraft as the government contends here, he must be given sufficient information to make his own determination. In this instance, that would involve divulging that Kalamazoo was not radar equipped, that the weather was two miles and getting worse, and that Grand Rapids radar scope could not assist him in making the landing as the map did not extend far enough, and the expected flight time, or distance, to Kalamazoo. While it may indeed have been imprudent to direct the pilot to Kalamazoo, it is reasonable to give him the information he needed to make that determination for himself, and for him to decide which risks he chose to assume. The government asserts that the aircraft would not have landed safely at any rate because it would have run out of fuel. Although I am tempted to believe that the government's expert is correct, and that the plane had 36 gallons of usable fuel, as the 1966 owner's manual indicated, and that the pilot did not use proper "leaning" techniques, that temptation does not alter the outcome as I cannot find by a preponderance of the evidence that this is so. The pilot has contended that the plane had a capacity of 42 gallons and that he had 39 gallons of usable fuel. As there was no record introduced on the fuel capacity of this particular plane, other than the pilot's testimony, I am not persuaded that there was no variance from the later model. I also cannot assume by a preponderance of the evidence that the pilot would have consumed fuel at the same rate on the flight from Grand Rapids to Kalamazoo and that he burned from the time of his departure. The controller did not discover exactly how much fuel in time the pilot thought he had. As the pilot is not now credited with interpretations he seeks to make after the fact when he did not create similar impressions at the time for decision, the government cannot succeed here. There is no showing that the controller would not have directed the pilot to Kalamazoo if it were VFR. Flight emergencies exist for many reasons. Weather is only one of them. If the pilot were running low on fuel, or thought he was, the controller had the duty to discover this fact in detail as the manuals indicate.
[6] The government's expert is presently a flight instructor and has previously been a pilot for the Michigan State Police. He has logged more than 6,000 flight hours, 90% of which has been in Michigan. He testified that he ascertained the amount of usable fuel by studying a 1966 owners manual for the Cessna 172 and opined that there would be no difference in the amount of usable fuel capacity for the 1965 model which was involved in the accident.