Aircraft Performance

1
Aircraft Performance

• Flying Further Than Any Other Aircraft in History

26,389.3 miles
Written for the Notre Dame Pilot Initiative By
the Pilots of the University of Notre Dame
2
Roadmap

• POH
• Density Altitude
• Takeoff Distance
• Cruise Performance, Power Fuel Burn
• Landing Distance
• Crosswinds

3
Pilots Operating Handbook (POH)

• Also known as Approved Flight Manual (AFM)
• Organized into Sections
• General
• Limitations
• Emergency Procedures
• Normal Procedures
• Performance
• Weight Balance
• Airplane Systems Description
• Handling, Service, Maintenance
• Supplements

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Frequent Terms

• Maximum Takeoff Weight (MTOW)
• Maximum gross weight at which the airplane is
  permitted to takeoff
• Maneuvering Speed
• Maximum speed for maneuvers at which full
  application of the primary flight controls cannot
  overstress the airframe

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Maneuvering Speed
VA 113 kts
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Density Altitude Revisited

• Density Altitude is pressure altitude corrected
  for nonstandard temperature
• Varies directly with temperature and humidity
• Varies indirectly with pressure
• It is a number which tells you what the airplane
  (wings and engine) feels

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Density Altitude
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Density Altitude Chart
9
Takeoff Distance

• Two Varieties
• Ground Roll
• Distance to Clear 50 ft obstacle
• Also known as Takeoff Distance
• Distance for aircraft to clear a 50-foot obstacle
  after a standing start at maximum takeoff power
• Factors
• ? Weight ? Distance (and speed)
• ? Air Density ? Distance
• ? Headwind ? Distance
• ? Slope ? Ground Roll
• ? Flaps ? Ground Roll
• ? Friction ? Ground Roll

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Cessna 172R
Takeoff Distance
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0 deg Takeoff Perf
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25 deg Takeoff Perf
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Climb Performance

• VxBest Angle of Climb
• Gain maximum altitude in shortest distance
• VYBest Rate of Climb
• Gain maximum altitude in shortest time
• Cruise Climb

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Cessna 172R
Climb Performance
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Cruise Flight

• An airplane is more efficient at altitude
• Wings
• Engines
• Weather is generally confined to the troposphere
  so you can fly over it
• Higher gives more options in case of emergencies
• Reserves
• Day VFR 30 minutes at normal cruising speed
• Night VFR 45 minutes at normal cruising speed

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Cessna 172R
Cruise Performance
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Cessna 172R
Cruise Performance
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Engine Performance
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Performance Cruise
VG VL/D 65 kts
20
Economy Cruise
VS 55 kts
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Endurance Graph
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Landing Distances

• Two Varieties
• Ground Roll
• Distance over a 50 foot obstacle
• Also known as Takeoff Distance
• Distance for aircraft to clear a 50-foot obstacle
  after a standing start at maximum takeoff power
• Factors
• ? Weight ? Distance (and speed)
• ? Air Density ? Distance
• ? Headwind ? Distance
• ? Slope ? Ground Roll
• ? Flaps ? Distance
• ? Friction ? Ground Roll
• Maximum performance landings are always
  accomplished with full flaps
• Stiff crosswinds sometimes dictate the use of
  partial flaps

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Cessna 172R
Landing Distance
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40 deg Landing Perf
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Boeing 727
Landing Distance
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Crosswinds

• Maximum Demonstrated Crosswind Component is the
  maximum crosswind that existed during FAA
  certification
• Often is not close to real maximum capability of
  aircraft
• Weak link is generally lack of rudder authority
  (not enough deflection)
• Often VX-Wind 0.3 VS0

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Crosswind Chart
30 knot wind, 30 deg off of the nose 26 knot
headwind 15 knot crosswind