Weight and balance


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Weight and balance

  1. 1. WEIGHT To determine if the helicopter is within weight limits you must consider The crew The weight of the basic helicopter Passengers Cargo Fuel
  2. 2. COMPUTING A HELICOPTER’S WEIGHT Basic empty weight- this is the starting point for weight computations which is the weight of the standard helicopter, equipment, unusable fuel, and operating fluids. Helicopter Flying Handbook 2012
  3. 3. COMPUTING A HELICOPTER’S WEIGHT Maximum gross weight- refers to the weight of the helicopter. - internal maximum gross weight: weight within the helicopter structure - external maximum gross weight: weight of the helicopter with an external load (can vary depending on where the external weight is attached to the helicopter) Helicopter Flying Handbook 2012
  4. 4. COMPUTING A HELICOPTER’S WEIGHT Weight limitations- this guarantees the structural integrity of the helicopter and enable pilots to predict helicopter performance accurately. - below minimum weight: could affect the handling characteristics of the helicopter - above maximum weight: could affect structural deformation or failure during flight Helicopter Flying Handbook 2012
  5. 5. BALANCE “Helicopter performance is not only affected by gross weight, but also by the position of that weight. It is essential to load the aircraft within the allowable center of gravity (CG) range specified in the Rotorcraft Flight Manual (RFM’s) weight and balance limitations.” Helicopter Flying Handbook 2012
  6. 6. CENTER OF GRAVITY Balancing the helicopter so that the fuselage is horizontal when in hovering flight is ideal for a pilot and balance of the helicopter. This should be accomplished when there is no cyclic pitch control needed. If CG is directly under the rotor mast then the helicopter hangs horizontal If CG is too far forward of the mast then the helicopter hangs with its nose down If CG is too far aft of the mast then the nose tilts up. (refer to picture on next page for visual) Helicopter Flying Handbook 2012
  7. 7. CG FORWARD OF FORWARD LIMIT “A forward CG may occur when a heavy pilot and passenger take off without baggage or proper ballast located after of the rotor mast. This situation becomes worse if the fuel tanks are located aft of the rotor mast because as fuel burns the CG continues to shift forward.” Helicopter Flying Handbook 2012
  8. 8. CG AFT OF AFT LIMIT “Without proper ballast in the cockpit, exceeding the aft CG may occur when: • A lightweight pilot takes off solo with a full load of fuel located aft of the rotor mast • A lightweight pilot takes off with maximum baggage allowed in a baggage compartment located aft of the rotor mast • A lightweight pilot takes off with a combination of baggage and substantial fuel where both are aft of the rotor mast”
  9. 9. LATERAL BALANCE Most training helicopter cabins are relatively narrow and most optional equipment is located near the centerline this makes lateral CG less critical in these aircraft. “However, some helicopter manuals specify the seat from which a pilot must conduct solo flight.” Also there are other situations that could affect lateral CG such as pilot weight and fuel quantity on one side of the helicopter. Helicopter Flying Handbook 2012
  10. 10. WEIGHT AND BALANCE CALCULATIONS Is the gross weight less than or equal to the maximum allowable gross weight? Add the weight of the items within the load (pilot, passengers, fuel, oil, cargo, baggage) to the basic weight of the helicopter Is the CG within the allowable CG range, and will it stay within the allowable range throughout the duration of flight including all loading configurations that may be encountered? CG or moment information from loading chart, tables or graphs in the RFM Helicopter Flying Handbook 2012
  11. 11. WEIGHT AND BALANCE CALCULATIONS Computing an accurate weight is important for balance  Ask passengers how much they weigh and add additional pounds for clothing (especially during winter months)  Baggage should be weighed Image: Standard weights for specific operating fluids Helicopter Flying Handbook 2012