WEIGHT & BALANCE - COMPREHENSIVE REFERENCE

[JoaoPaz]

WEIGHT & BALANCE - COMPREHENSIVE REFERENCE
Understanding Weight & Balance in Bush Flying

Weight and balance isn't just paperwork—it's survival. An overloaded aircraft won't climb out of a canyon. A badly balanced one won't handle right when you need it most. In bush flying, where you're often taking off from short, soft strips at high density altitudes, proper weight management is the difference between a safe flight and becoming a statistic.

Basic Principles
Maximum Takeoff Weight (MTOW): Never exceed this. Ever. Your aircraft was tested and certified at this limit. Beyond it, performance degrades rapidly and unpredictably.
Center of Gravity (CG): Must stay within limits. Too far forward = heavy controls, longer takeoff. Too far aft = unstable, potential loss of control.
Density Altitude Effect: Hot days and high elevations dramatically reduce performance. A fully loaded aircraft that climbs fine at sea level on a cold day might barely clear the trees at a mountain strip on a hot afternoon.

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Standard Passenger Weights

Adults

• Adult male (average): 190 lbs (86 kg)
  
• Adult female (average): 160 lbs (73 kg)
  
• Heavy adult (large build): 220-250 lbs (100-113 kg)
  
• Light adult (small build): 130-150 lbs (59-68 kg)
  

Children

• Teenager (13-17 years): 120-140 lbs (54-64 kg)
  
• Child (6-12 years): 80 lbs (36 kg)
  
• Young child (3-5 years): 40 lbs (18 kg)
  
• Infant/toddler (0-2 years): 20-30 lbs (9-14 kg)
  

Personal Baggage

• Standard baggage per passenger: 20-30 lbs (9-14 kg)
  
• Backpacker/camper gear per person: 40-60 lbs (18-27 kg)
  
• Winter clothing/survival gear add: +10-15 lbs (5-7 kg)
  
  

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Common Alaska Bush Cargo

Fuel Containers

• 5-gallon fuel drum (empty): 5 lbs (2 kg)
  
• 5-gallon fuel drum (full): 35 lbs (16 kg) - 30 lbs fuel + container
  
• 55-gallon fuel drum (empty): 25 lbs (11 kg)
  
• 55-gallon fuel drum (full): 400 lbs (181 kg) - 375 lbs fuel + drum
  
• Jerry can 5-gal (military style): 40 lbs full (18 kg)
  

Hunting & Fishing

• Moose quarter (deboned): 100-150 lbs (45-68 kg)
  
• Moose quarter (bone-in): 150-200 lbs (68-91 kg)
  
• Caribou (whole, field dressed): 200-300 lbs (91-136 kg)
  
• Bear hide (rolled): 40-80 lbs (18-36 kg)
  
• Fishing gear (rods, tackle, waders): 25-40 lbs (11-18 kg)
  
• Fish cooler (50-qt, full): 60-80 lbs (27-36 kg)
  
• Fish cooler (100-qt, full): 100-120 lbs (45-54 kg)
  

Camping & Outdoor Equipment

• Tent (4-person, complete): 15-25 lbs (7-11 kg)
  
• Sleeping bag (cold weather): 5-8 lbs (2-4 kg)
  
• Camping stove + fuel: 10-15 lbs (5-7 kg)
  
• Inflatable raft/kayak: 30-50 lbs (14-23 kg)
  
• Chainsaw (18-20" bar) + fuel: 25-30 lbs (11-14 kg)
  
• Chainsaw fuel/bar oil (1 gal each): 15 lbs (7 kg)
  
• Generator (portable 2000W): 50-60 lbs (23-27 kg)
  

Building & Construction Supplies

• 2x4 lumber (8 ft length): 13 lbs/board (6 kg)
  
• 2x6 lumber (8 ft length): 20 lbs/board (9 kg)
  
• Plywood sheet (4x8, 3/4"): 60 lbs (27 kg)
  
• Plywood sheet (4x8, 1/2"): 50 lbs (23 kg)
  
• Bag of concrete (80 lb): 80 lbs (36 kg)
  
• Box of roofing shingles: 60-80 lbs (27-36 kg)
  
• Toolbox (loaded contractor): 40-60 lbs (18-27 kg)
  

Food & Supplies (Remote Living)

• Grocery box (standard family): 30-40 lbs (14-18 kg)
  
• Case of canned goods (24 cans): 35 lbs (16 kg)
  
• 50 lb bag of flour/rice: 50 lbs (23 kg)
  
• Propane cylinder (20 lb, full): 37 lbs (17 kg) - 17 lbs propane + tank
  
• Propane cylinder (100 lb, full): 170 lbs (77 kg)
  
• Cooler with frozen food: 40-80 lbs (18-36 kg)
  

Dog Mushing & Pets

• Sled dog (working husky): 45-60 lbs (20-27 kg)
  
• Dog sled (racing): 30-40 lbs (14-18 kg)
  
• Dog food (50 lb bag): 50 lbs (23 kg)
  
• Dog crate (airline approved): 15-25 lbs (7-11 kg)
  

Scientific & Specialized Equipment

• Weather station (complete): 30-50 lbs (14-23 kg)
  
• Radio repeater equipment: 40-80 lbs (18-36 kg)
  
• Survey equipment (theodolite/GPS): 25-40 lbs (11-18 kg)
  
• Solar panel array (portable): 30-60 lbs (14-27 kg)
  

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Aircraft Fuel Weights

Critical Reference

• AvGas (100LL): 6.0 lbs/US gallon (0.72 kg/liter)
  
• Jet-A (turbine aircraft): 6.7 lbs/US gallon (0.80 kg/liter)
  

Example: A Cessna 185 with 84-gallon fuel capacity:

• Full tanks = 84 gal × 6 lbs = 504 lbs of fuel
  
• Half tanks = 42 gal × 6 lbs = 252 lbs of fuel
  
  

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Weight Calculation Workflow

Step-by-step process

1. Start with Empty Weight (from aircraft POH/logbook)
   • Example: Cessna 185 = 1,700 lbs empty
     
2. Add Pilot Weight
   • Example: 190 lbs pilot
     
3. Add All Passengers
   • Example: 2 adults (190 + 160) + 1 child (80) = 430 lbs
     
4. Add Baggage & Cargo
   • Example: 3 camping packs (60 × 3) + chainsaw (25) + cooler (80) = 285 lbs
     
5. Add Fuel Weight
   • Example: 60 gallons × 6 lbs = 360 lbs
     
6. Calculate Total Weight
   • Example Total: 1,700 + 190 + 430 + 285 + 360 = 2,965 lbs
     
7. Compare to MTOW
   • Example: Cessna 185 MTOW = 3,350 lbs
     
   • Margin: 385 lbs remaining ✓ Safe
     

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Common Bush Flying Scenarios

Scenario 1: Fishing Lodge Resupply

• 3 passengers @ 190 lbs avg = 570 lbs
  
• 6 grocery boxes @ 35 lbs = 210 lbs
  
• 2 propane tanks @ 37 lbs = 74 lbs
  
• Personal bags @ 25 lbs × 3 = 75 lbs
  
• Total cargo/PAX: 929 lbs
  

Scenario 2: Hunting Camp Drop-Off

• 2 hunters @ 200 lbs = 400 lbs
  
• 2 full camping packs @ 60 lbs = 120 lbs
  
• Hunting rifles/ammo = 25 lbs
  
• Food for 10 days = 80 lbs
  
• Tent/stove/gear = 40 lbs
  
• Total cargo/PAX: 665 lbs
  

Scenario 3: Moose Retrieval (Critical!)

• 1 pilot @ 190 lbs
  
• 1 hunter @ 200 lbs
  
• 2 moose quarters @ 150 lbs = 300 lbs
  
• Antlers/cape = 60 lbs
  
• Gear = 50 lbs
  
• Total cargo/PAX: 800 lbs
  
• ⚠️ Note: May require 2 trips depending on aircraft. Moose + full fuel often exceeds MTOW!
  

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Critical Bush Flying Weight Tips

Before You Load

• If it looks too heavy, it probably is
  
• Weigh questionable items when possible (portable luggage scale)
  
• Remember: fuel is heavy—full tanks mean less cargo capacity
  
• Consider density altitude: hot day + elevation = plan for less weight
  

Loading Strategy

• Heavy items should go as close to aircraft CG as possible
  
• Secure everything—loose cargo is dangerous cargo
  
• Distribute weight evenly side-to-side
  
• Check CG is within envelope (use aircraft loading chart)
  

Fuel Management

• Don't always fill to max—only take fuel you need + reserve
  
• Remember: burning fuel shifts CG aft during flight
  
• For short hops, partial fuel = more cargo capacity
  
• For long hops over remote terrain, fuel takes priority
  

The Alaska Bush Pilot's Rule

"When in doubt, make two trips. Nobody ever died from being too light."

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Weight & Balance Calculators

Most POHs (Pilot Operating Handbooks) include weight and balance worksheets. For digital help:

• Little Navmap: Aircraft > Aircraft Performance (enter empty weight and moment arms)
  
• ForeFlight: Has built-in W&B calculator for many aircraft
  
• Spreadsheet: Create your own for your specific aircraft
  
• POH Charts: Always the official reference
  
  

Remember: In bush flying, conservative weight planning isn't being cautious—it's being professional.

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Always consult your aircraft's POH for official weight and balance data specific to your tail number.