Since the engine is closely
cowled for efficient in-flight cooling, precautions should be taken to avoid
overheating on the ground. Full power checks on the ground are not recommended
unless the pilot has good reason to suspect that the engine is not turning up
The magneto check should be made at 1800 RPM as follows. Move ignition switch first tofl position and note RPM. Next move switch back to BOTH to clear the other set of plugs. Then move switch to the L position, note RPM and return the switch to the BOTH position. RPM drop should not exceed 150 RPM on either magneto or show greater than 50 RPM differential between magnetos. If there is a doubt concerning operation of the ignition system, RPM checks at higher engine speeds will usually confirm whether a deficiency exists.
An absence of RPM drop may be an
indication of faulty grounding of one side of the ignition system or should be
cause for suspicion that the magneto timing is set in advance of the setting
Prior to flights where
verification of proper alternator and alternator control unit operation is
essential (such as night or instrument flights), a positive verification can be
made by loading the electrical system momentarily (3 to 5 seconds) with the
landing lights during the engine runup (1700 RPM). The ammeter will remain
within a needle width of the initial reading if the alternator and alternator
control unit are operating properly.
It is important to check takeoff power early in the takeoff run. Any sign of rough engine operation or sluggish engine acceleration is good cause for discontinuing the takeoff.
Full power runups over loose gravel are especially harmful to pro peller tips. When takeoffs must be made over a gravel surface, it is very important that the throttle be advanced slowly. This allows the airplane to start rolling before high RPM is developed, and the gravel will be blown back of the propeller rather than pulled into it. When unavoidable small dents appear in the propeller blades they should be corrected immediately as described in Section 8 under Propeller Care.
After full power is applied,
adjust the throttle friction lock clockwise to prevent the throttle from
creeping from a maximum power position. Similar friction lock adjustment should
be made as required in other flight conditions to maintain a fixed throttle
WING FLAP SETTINGS
Normal and short field takeoffs are accomplished with wing flaps 0 deg. To clear an obstacle, an obstacle clearance speed of 63 KIAS should be used.
Soft field takeoffs are performed by lifting the airplane off the ground as soon as practical in a slightly tail-low attitude. If no obstacles are ahead, the airplane should be leveled off immediately to accelerate to a safer climb speed.
At takeoff weights of 2550
pounds or less, 100 flaps may be used if desired for minimum ground runs or
takeoffs from soft or rough fields.
Takeoffs into strong crosswinds
normally are performed with the minimum flap setting necessary for the field
length, to minimize the drift angle immediately after takeoff. With the ailerons
partially deflected into the wind, the airplane is accelerated to a speed
slightly higher than normal, and then pulled off abruptly to prevent possible
settling back to the runway while drifting. When clear of the ground, make a
coordinated turn into the wind to correct for drift.
LANDING GEAR RETRACTION
Landing gear retraction normally is started after reaching the point over the runway where a wheels-down, forced landing on that runway would become impractical. Since the landing gear swings downward approximately two feet as it starts the retraction cycle, damage can result by retracting it before obtaining at least that much ground clearance.
Before retracting the landing gear, the brakes should be applied momentarily to stop wheel rotation. Centrifugal force caused by the rapidly-spinning wheel expands the diameter of the tire. If there is an accumulation of mud or ice in the wheel wells, the rotating wheel may rub as it is retracted into the wheel well.