Figure 5-67. Positioned in the aircraft run up area before takeoff,  the WSC is ready to perform the pretakeoff checklist.  Before Takeoff Check  After Landing The before takeoff check is the systematic procedure for  making a check of the engine, controls, systems, instruments,  and avionics prior to fl ight. Normally, it is performed after  taxiing to a position near the takeoff end of the runway.  Taxiing to that position usually allows sufficient time  for the engine to warm up to at least minimum operating  temperatures. This ensures adequate lubrication and internal  engine clearances before being operated at high power  settings. Many engines require that the oil temperature or  engine temperature reach a minimum value, as stated in the  AFM/POH, before high power is applied. Some WSC aircraft are ram air cooled, where the cooling  air must be rammed into the cooling radiator during fl ight.  On the ground, however, little or no air is forced through  the radiator. Prolonged ground operations may cause engine  overheating. Some designs place the cooling radiators near  the propeller so the propeller produces reasonable airfl ow  to cool the engine. Air cooled two-stroke engine aircraft may have an integral  engine driven cooling fan and can idle indefi nitely without  overheating. Monitoring engine temperature to be within  limits is important for aircraft operations on the ground. After taxiing to the runway entrance runup area and before  beginning the pretakeoff check, the aircraft should be  positioned clear of other aircraft. When you taxi out to the  run up area, position your self where other aircraft can easily  taxi to a suitable run up area. There should not be anything  behind the aircraft that might be damaged by the prop  blast. To minimize overheating during engine run-up, it is  recommended that the aircraft be headed as nearly as possible  into the wind. After an aircraft is properly positioned for the  run-up, the nose wheel should be pointed straight. During the engine run-up, the surface under the WSC aircraft  should be firm (a smooth, paved, or turf surface, if possible)  and free of debris. Otherwise, the propeller may pick up  pebbles, dirt, or other loose objects and hurl them backward  or into the sail.  [Figure 5-67] While performing the engine run-up, the pilot must divide  attention inside to look at the instruments and outside the  aircraft to look for other traffic. If the parking brake slips,  or if application of the brakes is inadequate for the amount  of power applied, the aircraft could move forward unnoticed  if attention is fixed only inside the aircraft. Each aircraft has different features and equipment, and the  before takeoff checklist provided by the WSC manufacturer  During the after-landing roll, the WSC aircraft should be  gradually slowed to normal taxi speed before turning off  the landing runway. Any significant degree of turn at faster  speeds could result in the WSC aircraft tipping over and  subsequent damage.  [Figure 5-68] At towered airports, obtain clearance from tower when ready  for takeoff. At nontowered airports, when all air traffi c is  clear from observations and radio communications and while  holding short before the runway boundary (hold short) line,  announce the aircraft is entering the runway. This is a pilot’s  clearance at a self-announce airport to enter the runway. At  all airports, do a visual verification that there are no aircraft  landing before entering the runway. should be used to perform the run-up. Here is a general  checklist. •  Verify the strobe light is on (if applicable). •  Trim is set to proper speed for takeoff. •  Brakes are set. •  Ignition check—always divide attention into and out  of the flight deck in case the brakes can not hold the  aircraft still at the higher power settings. (Some ignition  checks are done at idle; see POH for engine specifi cs.)  If the brakes start to slip and the aircraft starts moving,  decrease power immediately and reevaluate how to run  up and keep the aircraft stationary during run up. Run up  engine to consistent rpm higher than idle. Switch from  both ignition systems to one and watch for a slight drop  in rpm. Do the same for the other ignition system. •  Verify engine temperatures (EGT, CHT, oil and/or water)  and oil pressure are within the acceptable ranges. 5-26