Aircraft Weight and Balance (CG Envelope)

Sum the station moments (empty, occupants, fuel, baggage), CG = total moment / total weight, legal only if weight <= max gross AND fwd_limit <= CG <= aft_limit. A 1,500 lb (39 in) aircraft with 340 lb front, 180 lb fuel, 200 lb baggage is 2,220 lb, CG 44.47 in -- legal. Fly lighter but pack 300 lb of baggage aft and it is 2,100 lb (under gross) yet CG 47.24 in -- BEHIND the 47 in aft limit and dangerously unstable. Fuel burn moves the CG, so both takeoff and landing CG must be in the envelope. A loading aid; the aircraft flight manual and the pilot in command govern.

total_weight = sum(w); total_moment = sum(w x arm); CG = total_moment / total_weight; in_envelope = weight <= max_gross AND fwd_limit <= CG <= aft_limit.

The station-moment weight-and-balance check of the FAA Weight & Balance Handbook (FAA-H-8083-1; AC 91-23), by name; the specific aircraft flight manual and the pilot in command govern.

The station-moment weight-and-balance method is published in the FAA Weight & Balance Handbook; the station weights, arms, and CG limits come from the aircraft's loading data.

Estimate. AHJ and licensed professional govern.

Field names used by the API: empty_weight_lb, empty_arm_in, front_weight_lb, front_arm_in, rear_arm_in, fuel_weight_lb, fuel_arm_in, baggage_weight_lb, baggage_arm_in, max_gross_lb, fwd_cg_limit_in, aft_cg_limit_in, total_weight_lb, cg_in

• Weight and CG both a load can be within gross weight and still out of CG; both must passFAA-H-8083-1
• Fuel burn fuel burn moves the CG, so both the takeoff and the zero-fuel CG must be in the envelopeFAA-H-8083-1
• Datum arms are measured from the aircraft datum per the flight manualAC 91-23