Chris Collins

Tools · aviation

Weight and balance

Weight and balance for your own aircraft: a profile with empty weight and arm, loading stations, fuel tanks and normal/utility CG envelopes, kept in your browser with JSON export; zero-fuel, take-off and landing weight and CG on the envelope with the fuel burn line and every limit checked; lb/in, kg/mm or kg/m; a printable sheet. Examples for the Cessna 172S, Piper Archer III and Cirrus SR22.

Added

How to use it

A training and planning aid. Your aircraft’s POH/AFM and its current weight-and-balance record govern. The three example profiles are not your aircraft: every airframe has its own empty weight and moment, and limits differ between models, serial ranges and revisions.

How to use it

  • Loading — pick an aircraft, choose the category (normal or utility, where the profile has one) and enter what you carry: people and bags at each station, fuel in each tank at the ramp, taxi fuel, and the flight time and average burn. The tool totals weight and moment and shows the ramp, take-off, landing and zero-fuel weight and CG, each against the envelope and the maximum weights, with how far you are from the forward and aft limits.

  • Anything out of limits is listed in red: CG forward or aft of the envelope, over a maximum weight, a station over its limit, combined baggage over its limit, more fuel than the tanks hold, burning more than you carry, or a load the utility category forbids (the rear seat, baggage). If the CG leaves the envelope only when the tanks run dry, that is a warning.

  • CG envelope — the chart plots weight against CG with the selected category shaded and the other dashed, take-off (T/O), landing (LDG) and zero fuel (ZFW), the fuel burn line from take-off to landing (orange) and on to empty tanks (purple, dotted). ⛶ Full screen (or F) enlarges it.

  • Aircraft — the example profiles are read-only. Make it my aircraft copies one (or Start a blank profile) and lets you enter everything from your own documents: basic empty weight and arm (or moment), the datum, each station’s arm, limit and default, each tank’s arm and usable fuel, taxi fuel, the maximum ramp, take-off, landing and zero-fuel weights, and the envelope corners for each category as CG,weight pairs in order round the polygon. Changing the weight, arm or fuel unit converts every figure (lb or kg; inches, millimetres, centimetres or metres; US gallons, litres or imperial gallons), and the fuel density follows the fuel type (avgas 6.0 lb/US gal or 0.72 kg/L; Jet A 6.7 lb/gal or 0.80 kg/L) or your own figure.

  • Your profiles are kept in this browser only. Export JSON saves one (or Export all mine), and Import JSON brings them back on another device.

  • Print sheet prints the loading table, the four totals, the limit checks and the envelope chart on one page, with a line for your signature.

Formulas

  • Moment = weight × arm; CG = Σ moment / Σ weight. Manuals in pounds and inches (and kg and mm) print moments divided by 1,000, and so does the table.

  • Take-off = ramp − taxi fuel; landing = take-off − fuel burned (time × average burn); zero fuel = everything but the fuel. Fuel is taken from each tank in proportion to its load.

  • The envelope check is a point-in-polygon test (shared with the E6B tool); the forward and aft limits at a weight are where a horizontal line crosses the polygon.

The example profiles and their sources

  • Cessna 172S — Cessna Model 172S Information Manual (1998, revised 2000): normal category 2,550 lb (ramp 2,558), CG 35.0 in at 1,950 lb or less, straight line to 41.0 in at 2,550 lb, aft 47.3 in; utility 2,200 lb (ramp 2,208), forward to 37.5 in at 2,200 lb, aft 40.5 in, rear seat and baggage empty. Arms: front seats 37 (adjustable 34 to 46), rear seats 73, fuel 48 (53 gal usable), baggage area 1 at 95 (120 lb), area 2 at 123 (50 lb), 120 lb combined. Empty weight 1,642 lb, moment 62,600 in-lb from the manual’s sample loading problem. Datum: the front face of the firewall.

  • Piper PA-28-181 Archer III — Archer III POH (serial 2843701 and up): 2,550 lb (ramp 2,558), CG 82.0 in at 2,050 lb or less to 88.6 in at 2,550 lb, aft 93.0 in; utility 2,130 lb (ramp 2,138), 82.0 to 83.0 in, aft 93.0, no baggage or rear passengers. Arms: front seats 80.5, rear 118.1, fuel 95.0 (48 gal), baggage 142.8 (200 lb). Empty weight 1,590 lb at 87.5 in from the POH’s sample loading. Datum: 78.4 in ahead of the wing leading edge.

  • Cirrus SR22 — Cirrus Design SR22 POH/AFM P/N 13772-001, reissue A (2003): 3,400 lb; CG forward FS 138.0 at 2,200 lb, 139.1 at 2,700, 141.4 at 3,210 and 143.8 at 3,400 lb, aft FS 148.1. Arms: front seats 143.5, rear 180.0, fuel 154.9 (81 gal usable), baggage 208.0 (130 lb). The empty weight (2,290 lb at 139.6) is a typical figure, not from the POH. Later SR22s (G3 onward, 3,600 lb) have different limits. Datum: 100 in forward of the firewall.

The envelopes are drawn down to the bottom of each manual’s chart; the lower edge is not a limit.

Limits

  • Not a substitute for the POH/AFM or the aircraft’s weighing record, and not an approved loading system. Check every figure of a profile against your own documents before relying on it.

  • Longitudinal CG only: no lateral CG, no helicopter or seaplane extras, and no moment-envelope charts (convert them to CG limits first).

  • Seats, baggage and fuel are each at one arm; adjustable seats and fuel whose arm moves with the quantity (some POHs give a table) need your own judgement or more stations.

  • The burn takes fuel from every tank in proportion; if you run one tank first, model it with your own fuel figures for each phase.

Related: E6B pilot calculators, Nav log / VFR planner, Aviation weather, Unit converter.

Linking to an example

The example aircraft’s loading can be written by hand: weights in pounds, fuel in US gallons, times in minutes. A profile of your own (and its loading) travels only in Share link's compressed ?s=.

Parameter Meaning Example

prof

aircraft: c172s, pa28, sr22

prof=pa28

cat

category: normal or utility

cat=utility

front, rear, bag, bag1, bag2

weight at each station (bag1/bag2 on the 172S, bag on the others)

front=340&rear=170

fuel

fuel at the ramp

fuel=40

taxi

taxi and run-up fuel

taxi=1.3

bt, br

flight time (minutes) and burn per hour

bt=90&br=8.5

example

one of the presets below; other parameters override it

example=pa28-poh

Presets:

  • c172s-full — Cessna 172S: two up front, 40 gal, 30 lb of bags, 1 h 30 min at 8.5 gal/h

  • c172s-aft — Cessna 172S: four people and 120 lb of bags — over weight and aft

  • c172s-utility — Cessna 172S in the utility category: solo, 30 gal

  • pa28-poh — the Archer III POH sample loading: 2,558 lb ramp, CG 91.5 in

  • sr22-family — SR22: two adults, two children, 60 gal, 2 h at 14 gal/h

Runs entirely in your browser; nothing you type leaves this page.