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dures (break-in) for metallic and non-asbes-
turn coordinator/turn and bank should indicate a right
tos organic linings. Proper brake lining
hand turn but the ball should skid to the left. The
conditioning should be completed before
vertical speed indicator should read zero and the
starting the low and high speed taxi tests.
artificial horizon should indicate level.
If not properly conditioned, the brake lining
will wear quickly and give poor braking
d. After each taxi run, inspect the aircraft for
action at higher speeds.
oil and brake fluid leaks. No leak should be consid-
c. The pilot should check the flight ered a minor problem. Every leak must be repaired
instruments for operation each time the aircraft is and the system serviced prior to the next taxi test.
SECTION 2. HIGH SPEED TAXI TESTS
First get use to the fact that you are now 30 feet wide and you steer with your feet. Wayne Nutsch
1. OBJECTIVE. To determine the aircraft s (2) In a tail wheel aircraft at 80 percent
high speed handling and braking parameters. of stall speed, the pilot should be able to lift the
tail and assume a take-off position. Again, if the tail
a. Propeller rotation will determine which rud-
cannot be raised, recheck the weight and balance and
der pedal is pressed to compensate for the asymmet-
CG range. Most likely there is a rearward CG prob-
rical thrust of the propeller blades. For example,
lem or the main gear is too far forward.
when viewed from the cockpit, a Volkswagen auto-
CAUTION: Heavy braking action at
motive engine mounted in a tractor configuration will
high speeds in tail wheel aircraft may
rotate the propeller counter-clockwise. In this case,
cause directional problems (ground
the pilot must use the left rudder pedal for high speed
loops) or nose overs.
taxi and take-off.
c. If runway conditions permit, duplicate each
b. As with every part of the flight testing pro-
taxi test with the flaps in the take-off and landing
gram, the high speed taxi tests should follow the
configuration. Record the flap effects on directional
FLIGHT TEST PLAN. Start slowly and do not
control and insert the information in the draft copy
progress to the next step until everyone is thoroughly
of the aircraft s flight manual.
satisfied with the aircraft and his/her own perform-
ance.
d. Determine the approximate point on the
runway where lift-off will occur and mark it with
c. Each taxi run should be 5 mph faster than
a green flag if no other existing reference is available.
the last run until the aircraft is within 80 percent
of the predicted stall speed. Prior to reaching the
e. Determine how much runway the pilot will
predicted stall speed, the pilot should test aileron
need if it becomes necessary to abort the take-off.
effectiveness by attempting to rock the wings
This is usually accomplished by accelerating to 80
slightly. As taxi speeds increase, the rudder becomes
percent of lift off speed, bringing the engine back
more responsive and directional control will
to idle, and applying heavy braking action to bring
improve.
the aircraft to a full stop. After each take-off/abort
test, the brakes must be allowed to COOL DOWN.
(1) In a nose gear aircraft, the pilot should
The lining must be examined carefully and replaced
be able to raise the nose of the aircraft to a take
if necessary.
off attitude at 80 percent of the stall speed. If the
nose cannot be raised at this speed, the weight and
f. After determining the distance required to
balance and CG range should be rechecked. Most
come to a full stop after aborting, add 30 percent
likely there is a forward CG problem or the main
to the distance. Measure that distance from the
gear is too far aft.
OPPOSITE end of the active runway which will be
30
5/24/95 AC 90-89A
used. If no existing reference is available, mark it h. Notes.
with a red flag. The taxi tests are completed when
(1) The first high speed taxi tests should
the test pilot is satisfied with both the aircraft s and
be made in a no wind or a light head wind condition.
his/her individual performance. Prior to the first
The pilot should ensure that the tests will not inter-
flight, the aircraft should be thoroughly inspected
fere with the normal airport operations or create a
with special attention given to the landing gear, brake
safety hazard for other aircraft.
system, engine, and propeller.
(2) If the aircraft s engine is not a U.S. type
g. During this inspection all discrepancies
certificated engine, the pilot should determine which
must be fixed. Examine the screens/filters for metal,
way the propeller rotates.
flush the fuel system, and clean all the screens/filters.
(3) Pilots of tail wheel aircraft must always
Perform a leak check on the engine and the fuel
be aware that ground loops are possible at any speed.
system by running-up the engine.
This is true especially if the main landing gear is
located too far forward of the aircraft s CG.
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AC 90-89A 5/24/95
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5/24/95 AC 90-89A
CHAPTER 3. THE FIRST FLIGHT
It is critically important that a test pilot never succumb to the temptation to do too much too soon, for
that path leads but to the grave. Richard Hallion (1987)
SECTION 1. GENERAL
1. OBJECTIVE. To take every precaution to c. A safe and uneventful first flight begins
ensure that the first test flight is an uneventful with verifying all emergency equipment and person-
nel are standing by, radio communications are func-
one.
tional, members of the crew are briefed, weather is
2. GENERAL.
ideal, and the aircraft is airworthy. The pilot must
be rested and physically and mentally ready for the
a. The first flight is an important event for
first flight and every flight thereafter. The pilot also
an amateur-builder. As important as it is, it should
should review any new data developed for the air-
not be turned into a social occasion. This puts enor-
craft s flight manual.
mous peer pressure on the pilot to fly an aircraft
that may not be airworthy or to conduct the flight
d. The first flight should be flown a thousand
in inclement weather.
times: the first 500 on paper, the next 499 flights
in the test pilot s mind -- and once in actuality. The
b. A professional will avoid this trap by fol-
first flight test should be so well-rehearsed by the
lowing the FLIGHT TEST PLAN and inviting only
test pilot and ground crew that the first flight is a
those members of the crew needed to perform
non-event.
specialized tasks when testing the aircraft.
33
AC 90-89A 5/24/95
31. RECOMMENDATIONS. (5) Fuel valve is in the proper position and
vent lines are open.
a. The best time to test fly an aircraft is usu-
(6) Trim tabs set in the take-off position.
ally in the early morning when the winds are calm,
and the pilot is well rested.
(7) Altimeter set to the field elevation and
cross-checked with the local altimeter setting.
b. In addition to a pilot s knee board, a small
portable tape recorder or video camera properly
(8) The complete control system has been
mounted to the aircraft is an excellent way to record
given a functional check.
data.
(9) Check of all ground and air commu-
c. Good communication with the ground is
nications frequencies for proper operation.
essential for data exchange and safety.
(10) Engine cowling and airframe inspec-
4. FIRST FLIGHT INSPECTION.
tion plates/fairings secured.
a. Prior to the first flight, the aircraft should
(11) The airspeed indicator marked with
be given a good pre-flight inspection by the pilot
sticky tape at the predicted BEST CLIMB speed,
and at least one other experienced individual. A thor-
BEST GLIDE speed and MANEUVERING speed.
ough aircraft pre-flight inspection should ensure that:
If these speeds are not available from prototype flight
test data, the following are conservative guidelines
(1) The fuel on board is four times the
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