Cessna Skyhawk 172N Pilot Operating Handbook page 251

Supplement POH
Reims/Cessna (F) 172 N&P
with TAE 125-02-114
BATTERY CHECK
If there is doubt regarding the battery conditions or functionality
the battery has to be checked after warm-up as follows:
Switch off the alternator while the engine is running (battery
remains "ON")"
Perform a 10 sec. engine run. The voltmeter must remain in the
green range. If not, the battery has to be charged or, if
necessary, exchanged.
After this test the alternator has to be switched on again.
TAKE-OFF
POWER CHECK
It is important to check full load engine operation early in the
take-off roll. Any signs of rough engine operation or sluggish
engine acceleration is good cause for discontinuing the take-off.
If this occurs, you are justified in making a thorough full load
static run-up before another take-off is attempted.
After full load is applied, adjust the thrust lever friction control to
prevent the thrust lever from creeping back from a maximum
power position. Similar friction lock adjustments should be
made as required in other flight conditions to maintain a fixed
thrust lever setting.
WING FLAP SETTINGS
Flap deflections greater than 10° are not approved for normal
and short field take-offs. Using 10° wing flaps reduces the
ground roll and total distance over a 15 m/50 ft obstacle by
approximately 10%.
Page 4-21
Issue 2
Revision 7, Jan. 2018