Objective

To determine that the member exhibits satisfactory knowledge, risk management, and skills associated with operating an airplane safely within the parameters of its performance capabilities and limitations.

Reading

This is the required reading for this lesson. Numbers in [brackets] indicate the starting and ending page in the referenced reading material. Read all the pages and sections referenced.

• Airplane Flying Handbook
  • Chapter 13 - Transition to Multiengine Airplanes
    • [13-10 to 13-14] "Performance and Limitations" to "Weight and Balance"
• Pilot's Handbook of Aeronautical Knowledge
  • Chapter 10 - Weight and Balance
    • [10-1 to 10-11]
  • Chapter 11 - Aircraft Performance
    • [11-1 to 11-28]

Summary

The notes below highlight the important parts in the referenced material. Reading the notes without having read the actual referenced material is generally not sufficient to pass the written exam!

The performance or operational information section of the Aircraft Flight Manual/Pilot's Operating Handbook (AFM/ POH) contains the operating data for the aircraft; that is, the data pertaining to takeoff, climb, range, endurance, descent, and landing. The use of this data in flying operations is mandatory for safe and efficient operation. Considerable knowledge and familiarity of the aircraft can be gained by studying this material.

PHAK - Chapter 10

• The following (abbreviated) list of terms and their definitions is standardized, and knowledge of these terms aids the pilot to better understand weight and balance calculations of any aircraft.
  • Arm (moment arm) - the horizontal distance in inches from the reference datum line to the CG of an item.
  • Center of gravity (CG) - the point about which an aircraft would balance if it were possible to suspend it at that point.
  • CG limits - the specified forward and aft points within which the CG must be located during flight.
  • CG range - the distance between the forward and aft CG limits indicated on pertinent aircraft specifications.
  • Fuel load - the expendable part of the load of the aircraft.
  • Maximum landing weight - the greatest weight that an aircraft is normally allowed to have at landing.
  • Maximum takeoff weight - the maximum allowable weight for takeoff.
  • Moment - the product of the weight of an item multiplied by its arm.
  • Station - a location in the aircraft that is identified by a number designating its distance in inches from the datum.
• Determine Loaded Weight and CG
  • Computational Method
  • Graph Method
  • Table Method
• Center of gravity (CG) is calculated as follows:
  • Determine the weights and arms of all mass within the aircraft
  • Multiply weights by arms for all mass to calculate moments
  • Add the moments of all mass together
  • Divide the total moment by the total mass of the aircraft to give an overall arm

    Example:

     

    	Mass	Arm	Moment
    Empty aircraft	1,495.0	101.4	151,593.0
    Pilot and passengers	380.0	64.0	24,320.0
    Fuel	180.0	96.0	17,280.0
    Totals	2,055.0	94.0	193,193.0

    
    To find the center of gravity, we divide the total moment by the total mass: 193,193 / 2,055 = 94.01 inches behind the datum plane.

PHAK - Chapter 11

• Pressure Altitude
  • Height above the standard datum plane (SDP)
  • The SDP is a theoretical level at which the pressure of the atmosphere is 29.92 inHg and the weight of air is 14.7 psi
• Density Altitude
  • Pressure altitude corrected for nonstandard temperature
  • As the density of the air increases (lower density altitude), aircraft performance increases
  • Humidity must be taken into consideration. Expect a decrease in overall performance in high humidity conditions.
• Performance
  • Straight-and-Level Flight
    • Parasite drag predominates at high speed, induced drag predominates at low speed
  • Climb Performance
    • Angle of Climb - Comparison of altitude gained relative to distance traveled.
    • Rate of Climb - Comparison of altitude gained relative to the time needed to reach that altitude
  • Range Performance
• Performance Charts
  • Allow a pilot to predict the takeoff, climb, cruise, and landing performance of an aircraft.
  • Interpolation
    • By taking the known information, a pilot can compute intermediate information.
  • Density Altitude Charts
  • Takeoff Charts
  • Climb and Cruise Charts
  • Crosswind and Headwind Component Chart
  • Landing Charts
  • Stall Speed Performance Charts

Sim Pilot Notes

These notes highlight the differences between simulator and real-world flying. These differences are most often due to simulator limitations or specific VATSIM rules.

PHAK - Chapter 10

• Although center of gravity is harder to determine in the sim due to both lack of proper documentation and identifiable stations, the sim pilot should nevertheless be aware of the total weight of the aircraft and attempt to balance the virtual load so that the CG stays within limits.
• For the purpose of the checkride it is expected that the student has access to load & balance information and can provide these references to the examiner upon request to verify the calculated weights and CG

PHAK - Chapter 11

• For the purpose of the checkride it is expected that the student has access to aircraft's performance information and can provide these references to the examiner upon request to verify the calculated takeoff and landing distance calculations

Tomas Hansson (This email address is being protected from spambots. You need JavaScript enabled to view it.)
Chief Flight Instructor, VATSTAR
DISCLAIMER: all information contained herein is for flight simulation purposes only.
March 2021