Why Weight And Balance Is So Important To Flights

Last week, we told the story of the Qantas flight, where every passenger needs to step onto the scale before stepping inside the plane. Flights to Lord Howe Island carry both tourists and cargo and are meticulously calculated for weight and balance. But why is it so important?

Many travelers have, at some point, stood anxiously waiting to weigh their luggage at check-in, praying that holiday reading would not result in exceeding the airline’s weight limit with extra charges as a result. However, very rarely is one asked to step on the scale oneself before departure.

Stepping on the scale for LDH

Meanwhile, this is sometimes the case for passengers traveling from the Australian mainland to the World Heritage-listed Lord Howe Island, a tiny 14.55sq km island in the Tasman sea. The only way to reach the island with a commercial airline is to travel on one of Qantas’ Dash-8 Q200s from either Sydney or Brisbane.

The Dash-8 Q200 is a 36-seater turboprop. According to Qantas’ Roo Tales, if there are more than 27 passengers aboard any one flight, everyone needs to be weighed before getting onboard. This is so the pilot can calculate the correct amount of fuel required, and determine how much freight capacity the aircraft will have.

But isn’t weight always a factor on flights for fuel calculation and center of gravity? How do pilots determine the weight of the plane with people in it without having everyone step on the scales before departure? And why is it so important?

Airlines generally use an estimated weight based on passenger gender (93 kg for men, and 75 kg for women). This estimate is usually higher than the actual weight, which often results in airplanes carrying too much fuel. Of course, this is not ideal in terms of efficiency or from an environmental perspective; however, a marginal error in weight calculation for big commercial jetliners is not critical.

Flight 5481

For smaller turboprop aircraft, however, even smaller mistakes in calculating weight and balance can turn out to have fatal consequences. On January 8th, 2003, a Beechcraft 1900D operating Air Midwest Flight 5481 stalled while departing from Charlotte Douglas International Airport. The plane crashed into a hangar, killing all 21 passengers and crew on board, as well as one person on the ground.

Flight 5481 took off at 08:46, and immediately after, the plane’s nose began to pitch up, reaching a maximum of 54 degrees. Despite the pilots’ efforts to push the nose down, the aircraft stalled and descended out of control, crashing approximately 35 seconds after taking off.

Over 200 kg above max take-off weight

The weight of the aircraft turned out to have been higher than calculated, which provided an incorrect readout for the plane’s center of gravity, causing it to rise too steeply. The actual weight of every passenger turned out to be 9 kg higher than the estimation. After checking the weight of luggage retrieved from the crash site, it turned out that the aircraft had been 264 kg above its maximum take-off weight.

So should you ever find yourself on a smaller turboprop flight where the airline asks to know your exact weight, please do not feel offended. It is for a very good cause.