8. Mixture and Idle Speed Check: After completing the initial engine ‘‘run-in’’ tests, check
the idle speed and mixture settings. To determine if the mixture setting is correct, perform the follow-
ing:
(a) Warm up the engine until all readings are normal
(b) Adjust the engine rpm to the recommended idle rpm
(c) Slowly pull the mixture control back to idle cut-off
(d) Just before the engine quits, the engine rpm should rise about 50 rpm if the mixture is properly
adjusted. If the rpm drops off without any increase in rpm, the idle mixture is set too lean. If the rpm
increases more than 50 rpm, the idle mixture is set too rich.
9. Magneto - Ignition Check:
(a) The magneto checks should be smooth and the difference between both magnetos rpm drops
should average about 50 rpm. (engine manual may require more drop in RPM. Check. The builder also
should perform a ‘‘HOT MAG’’ check, to ensure against the engine, on its own, deciding when and
where to start. To perform a hot mag check, run up the aircraft until the engine is warm. At idle rpm
turn the magneto switch off; the engine should stop running. If the engine continues to run, one or both
of the magnetos is hot (not grounded).
(b) The usual causes for a hot magneto area broken ‘‘P’’ lead coming out of the magneto or
a bad magneto switch. THIS IS AN IMMEDIATE THREAT TO THE PERSONAL SAFETY OF
ANYONE NEAR THE AIRPLANE AND MUST BE REPAIRED AT ONCE.
10. Carburetor Heat:
Be certain there is a positive reduction in rpm each time ‘‘carb heat’’ is applied. If there is no
reduction, or the rpm drop is less than expected, check the carb heat control in the cockpit and on
the carb heat air box for full travel. Also check for air leaks in the ‘‘SCAT TUBE’’ that connects the
heat muff to the carburetor air box.
FOLLOW THE ZODIAC“GROUND TEST CHECK LIST”
Request this form from the manufacturer.
TAXI TESTS.
a. The pilot should spend an hour or more in the cockpit to become accustomed to the aircraft’s takeoff
position. This small but important aspect of training will help the pilot avoid overreacting to an
unexpected deck angle on the first flight.
NOTE: All taxi tests should always be monitored by a minimum of one other member of the flight
test team, who will watch for evidence of fire/smoke or other problems not visible to the pilot.
b. The taxi tests should begin with a taxi speed no faster than a man can walk. The pilot should spend
this time getting acquainted with the aircraft’s low speed handling characteristics by practicing 90, 180,
and 360 degree turns and braking action. The pilot should also remember that monitoring the oil
pressure, and oil temperature, and maintaining them within limits is a critical function that must not be
overlooked.
NOTE: The Pilot should be aware that some aircraft brake manufacturers have specific brake lining
conditioning procedures (break-in) for metallic and non-asbestos organic linings. Proper brake lining
conditioning should be completed before starting the low and high speed taxi tests. If not properly
conditioned, the brake lining will wear quickly and give poor braking action at higher speeds.
c. The pilot should check the flight instruments for operation each time the aircraft is taxied out. The
compass should match the magnetic heading of the runway or taxi way the aircraft is on. When making
a turn (e.g., right hand turn), the turn coordinator/turn and bank should indicate a right
hand turn but the ball should skid to the left. The vertical speed indicator should read zero and the
artificial horizon should indicate level.
d. After each taxi run, inspect the aircraft for oil, fuel and brake fluid leaks. No leak should be
considered a minor problem. Every leak must be repaired and the system serviced prior to the next taxi
test.
Appendix 1 NOV 09
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