The International Cessna^® 170 Association

MY FUEL VALVE PLACARD READS BOTH TKS ON TAKE OFF & LANDING , 5000' & ABOVE SWITCH IMMEDIATELY TO LEFT OR RIGHT TK. IVE READ MOST THE INFO PERTAINING TO THIS ON HERE WITH THE EXCEPTION OF THE 5000' & ABOVE . I FLY ON BOTH & NEVER SWITCH TO LEFT OR RIGHT,,,, HAVE NEVER HAD ANY PROBLEMS, CURIOUS IF ALL 170A's ARE PLACARD THIS WAY & WHATS THE REASON BEHIND THIS ? I BELIEVE THE PLACARD IS OEM, PLANE DOES HAVE THE O-360 CONVERSION

That placard has been incorrectly transferred to your 170 from the 172 series. It does not apply to your 170. There is no need to ever switch off of BOTH, unless you have some unusual development to consider.
The only time I switch off of BOTH in flight, is when I once ran some autogas for an hour to get where I could buy avgas. I was low on fuel at Ol'Gar's and put in 5 gallons of mogas to get to an airport....took off on BOTH, ran on the autogas to get rid of it asap, and then it's been on Both now for ten years or so...except when it's parked or stored in the hangar. (Then it's "OFF", of course.)

Thanks George , good to know, can fly without that in back of my mind now

Oklahotshot, so what fuel flow do you get out of your O-360 say at sea level and 4500ft. And what prop do you use ? I run a Sensenich prop fixed pitch at 60 ins of pitch . Good prop for my operations.

oklahotshot wrote:Thanks George , good to know, can fly without that in back of my mind now

Last year I included the airworthiness directive 72-07-02 and supporting Cessna documentation in the Maintenance Library here. This AD applies to the earliest C-172's. Except for the change to the gooseneck vent--it moved to either above or below the left wing outboard of the tank--the fuel lines appear to be identical to the C-170. So I'm puzzled as to why the 170 did not get included in this AD. Has anyone here experienced symptoms of fuel vapor lock above 5000'?

The 170 was not included because it did not suffer from the longer vent lines which may have changed vent-pressures within the system. Turbulence was suspected of introducing air into the system which did not "percolate" out as quickly in the long vent lines. The 170 doesn't have such long vent lines, having only the overhead gooseneck. The Cessna Pilots Assoc'n issued a more detailed explanation about a decade ago, and somewhere I hope I've got a copy of that article. Unfortunately, it's most likely on a hard-drive and that was 4 IBM computers-ago...and I've been slow to switch to the better Apple products.

"Computers manufactured by companies such as IBM and millions of others are by far the most popular, with about 70 million machines in use worldwide. Macintosh fans, on the other hand, may note that cockroaches are far more numerous than humans, and that numbers alone do not denote a higher life form."-New York Times, November 26, 1991

ghostflyer wrote:Oklahotshot, so what fuel flow do you get out of your O-360 say at sea level and 4500ft. And what prop do you use ? I run a Sensenich prop fixed pitch at 60 ins of pitch . Good prop for my operations.

Around 9 to 9.5 gph jus playin , havent had a chance to chk on longer xc trips yet , the prop is a constant speed MT three blade, am pleased with it , is very sensitive to any input , quiet & smooth, alil learning curve for me when throttle is decreased, feels like an airbrake , the two blade Hartzell did a great job also, but wanted to do away with rpm limits ( 2000 -2250 ) & 100 hr AD .