2. WEIGHT
To determine if the helicopter is within weight limits you
must consider
The crew
The weight of the basic helicopter
Passengers
Cargo
Fuel
3. 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
4. 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
5. 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
6. 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
7. 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
8.
9. 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
10. 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”
11. 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
12. 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
13. 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