Skip to content

The technical challenges of flying near-empty planes

March 27, 2020
6 min read
United Dreamliner economy cabin
The technical challenges of flying near-empty planes
This post contains references to products from one or more of our advertisers. We may receive compensation when you click on links to those products. Terms apply to the offers listed on this page. For an explanation of our Advertising Policy, visit this page.

Airlines are flying very few passengers and near-empty aircraft these days, courtesy of the COVID-19 pandemic.

A captain for a large international carrier told me he recently flew a Boeing 787 Dreamliner to Los Angeles. His aircraft normally seats 255 passengers, but there were only 25 on board. Separately, a first officer for a U.S. carrier said in an email there were three passengers on her most recent flight.

In an era where airlines have typically 85% of their seats full with paying passengers, these numbers are unheard of. But revenue aside, flying empty or near-empty planes requires operational changes due to physics. It's all because of weight and balance.

When an airplane flies so light on passengers (and their luggage), passengers are either moved around the cabin or extra ballast is added to the baggage hold to make sure it all balances out.

For more travel tips and news, sign up for TPG’s daily email newsletter

Airplanes function like a giant seesaw. By design, the center of gravity of the aircraft is near the main landing gear. But the center of gravity is not constant because fuel, passengers, baggage and cargo differ on each flight and for each airplane. The center of gravity even changes during flight.

"An operator calculates takeoff weight by adding the operational empty weight of the aircraft, the weight of the passengers, cargo payload, and the weight of fuel. The objective is to calculate the takeoff weight and center of gravity of an aircraft as accurately as possible," according to the Federal Aviation Administration.

"The center of gravity moves backwards as we burn fuel," said Carolina Larsson, a first officer with a regional airline flying Embraer E175 around North America. Her airplane has a forward center of gravity due to its engines being mounted forward of the wings.

Captain Chris Brady, a commercial pilot who runs the Boeing 737 Technical Site, explained that typically an airline's dispatcher gives the pilots a form with the number of passengers and which third of the cabin — front, middle, or rear — they are seated in. The form also has the number of bags and cargo and where it's physically loaded on the plane.

Sign up for our daily newsletter

"We then input that data along with the fuel load and various other factors — such as flap setting — into the computer and it spits out both the balance data and takeoff speeds. With the balance data, we set the stabilizer trim so that the aircraft is in trim for the take off," Brady explained, referring to the control surfaces on the tail that keep an airplane longitudinally stable.

A Southwest Boeing 737-700 takes off from the Atlanta airport (Photo by Alberto Riva/The Points Guy)

"For the Boeing 737 and Airbus A320 families there is no weight and balance problem flying empty or nearly empty as long as the passengers are evenly distributed throughout the cabin. The aircraft will be in balance. This is of course all checked before departure by the pilots," Brady said.

Still, "if the balance calculation shows that the aircraft is out of allowable trim limits for takeoff or landing, then we will instruct the cabin crew to move passengers so that the aircraft is in balance — but this is a very rare occurrence," Brady said.

It's less rare for pilots on smaller regional jets.

"We move passengers around every four flights or so," Larsson, the Embraer E175 pilot, said, noting that it happens even when planes are flying with more passengers.

"The E175 is tail-heavy. And sometimes, the rear of the cabin is full of economy passengers but the front of the cabin is not. When we plug in the passenger loads, the flight computer will inform us that we need to move a certain number of passengers from the rear section to the middle or the front. For example, it will say to take either four passengers from the rear to the front cabin or six passengers from the middle to the front. Those that bought an economy ticket might be in for a bump up to business class," she said. "We call up the flight attendants and they move the passengers, often asking for volunteers, without specifying why or where they will get seated."

While the E175 is tail-heavy, despite having a forward center of gravity, other regional jets such as the CRJ series made by Bombardier are nose-heavy. Those planes have a baggage section at the rear of the aircraft to compensate. But still, weight must sometimes be shifted around or added.

For some aircraft and under some circumstances such as an already light fuel load, the ground crew will load 50-pound sandbags, sometimes more than a dozen. The ballast can consist of bags of sand or pebbles, ballast blocks or bars. The bags are loaded into either the forward or the rear baggage hold, depending on the specific aircraft. Larsson said that she's never had to ask for ballast to be added for her flights. Captain Brady concurs: "I only ever had to use ballast on air test flights which are post maintenance check flights when we needed a high fuel load but had zero passengers. The ballast was whatever the engineers had handy—usually spare tires."

All of the calculations generated by the flight computer are based on certain standard weights, originally devised by the FAA. For many years, those weights increased from time to time as the flying public grew, well, larger.

Here are the standard weights published in 2005, the last time the table was updated. The figures include the estimated weight of a passenger's luggage as well.

Standard weights for summer and winter. Image via FAA.
Standard weights for summer and winter. (Screen cap from FAA site)

Nowadays, the FAA simply releases methods to calculate the weights of passengers rather than specify standard weights.

For the record, I'm trying to do my part to help the airlines by losing a few pounds.

Mike Arnot is the founder of Boarding Pass NYC, a New York-based travel brand and a marketing consultant to airlines, none of which appear in this article. Featured image The empty economy-class cabin of a United Boeing 787, by Zach Griff / The Points Guy

Featured image by United 787 economy cabin (Photo by Zach Griff/The Points Guy)

TPG featured card

Best for the well-traveled foodie
TPG Editor‘s Rating
Card Rating is based on the opinion of TPG‘s editors and is not influenced by the card issuer.
4 / 5
Go to review
Apply for American Express® Gold Card
at American Express's secure site

Rewards

3 - 4X points
4XEarn 4X Membership Rewards® Points at Restaurants, plus takeout and delivery in the U.S.
4XEarn 4X Membership Rewards® points at U.S. supermarkets (on up to $25,000 per calendar year in purchases, then 1X).
3XEarn 3X Membership Rewards® points on flights booked directly with airlines or on amextravel.com.

Intro offer

60,000 bonus points
Earn 60,000 Membership Rewards® points after you spend $4,000 on eligible purchases with your new Card within the first 6 months of Card Membership.

Annual Fee

$250

Recommended Credit

670-850
Excellent/Good
Credit ranges are a variation of FICO© Score 8, one of many types of credit scores lenders may use when considering your credit card application.

Why We Chose It

There's a lot to love about the Amex Gold card. It's been a fan favorite during the pandemic because of its fantastic rewards rate on restaurants (that includes takeout and delivery in the U.S.!) and U.S. supermarkets. If you're hitting the skies soon, you'll also earn bonus points on travel. Paired with up to $120 in Uber Cash (for U.S. Uber rides or Uber Eats orders) and up to $120 in annual dining statement credits at eligible partners, there's no reason that the foodie shouldn't add this card to their wallet. Enrollment required.

Pros

  • 4x on dining at restaurants and U.S. supermarkets (on the first $25,000 in purchases per calendar year; then 1x)
  • 3x on flights booked directly with the airline or with Amex Travel
  • Welcome bonus of 60,000 points after spending $4,000 in the first six months

Cons

  • Weak on travel outside of flights and everyday spending bonus categories
  • Not as useful for those living outside the U.S.
  • Some may have trouble using Uber/food credits
  • Few travel perks and protections
  • Earn 60,000 Membership Rewards® points after you spend $4,000 on eligible purchases with your new Card within the first 6 months of Card Membership.
  • Earn 4X Membership Rewards® Points at Restaurants, plus takeout and delivery in the U.S., and earn 4X Membership Rewards® points at U.S. supermarkets (on up to $25,000 per calendar year in purchases, then 1X).
  • Earn 3X Membership Rewards® points on flights booked directly with airlines or on amextravel.com.
  • $120 Uber Cash on Gold: Add your Gold Card to your Uber account and each month automatically get $10 in Uber Cash for Uber Eats orders or Uber rides in the U.S., totaling up to $120 per year.
  • $120 Dining Credit: Satisfy your cravings and earn up to $10 in statement credits monthly when you pay with the American Express® Gold Card at Grubhub, The Cheesecake Factory, Goldbelly, Wine.com, Milk Bar and select Shake Shack locations. Enrollment required.
  • Choose the color that suits your style. Gold or Rose Gold.
  • No Foreign Transaction Fees.
  • Annual Fee is $250.
  • Terms Apply.
  • See Rates & Fees
Apply for American Express® Gold Card
at American Express's secure site
Terms & restrictions apply. See rates & fees
Best for the well-traveled foodie
TPG Editor‘s Rating
Card Rating is based on the opinion of TPG‘s editors and is not influenced by the card issuer.
4 / 5
Go to review

Rewards Rate

4XEarn 4X Membership Rewards® Points at Restaurants, plus takeout and delivery in the U.S.
4XEarn 4X Membership Rewards® points at U.S. supermarkets (on up to $25,000 per calendar year in purchases, then 1X).
3XEarn 3X Membership Rewards® points on flights booked directly with airlines or on amextravel.com.
  • Intro Offer
    Earn 60,000 Membership Rewards® points after you spend $4,000 on eligible purchases with your new Card within the first 6 months of Card Membership.

    60,000 bonus points
  • Annual Fee

    $250
  • Recommended Credit
    Credit ranges are a variation of FICO© Score 8, one of many types of credit scores lenders may use when considering your credit card application.

    670-850
    Excellent/Good

Why We Chose It

There's a lot to love about the Amex Gold card. It's been a fan favorite during the pandemic because of its fantastic rewards rate on restaurants (that includes takeout and delivery in the U.S.!) and U.S. supermarkets. If you're hitting the skies soon, you'll also earn bonus points on travel. Paired with up to $120 in Uber Cash (for U.S. Uber rides or Uber Eats orders) and up to $120 in annual dining statement credits at eligible partners, there's no reason that the foodie shouldn't add this card to their wallet. Enrollment required.

Pros

  • 4x on dining at restaurants and U.S. supermarkets (on the first $25,000 in purchases per calendar year; then 1x)
  • 3x on flights booked directly with the airline or with Amex Travel
  • Welcome bonus of 60,000 points after spending $4,000 in the first six months

Cons

  • Weak on travel outside of flights and everyday spending bonus categories
  • Not as useful for those living outside the U.S.
  • Some may have trouble using Uber/food credits
  • Few travel perks and protections
  • Earn 60,000 Membership Rewards® points after you spend $4,000 on eligible purchases with your new Card within the first 6 months of Card Membership.
  • Earn 4X Membership Rewards® Points at Restaurants, plus takeout and delivery in the U.S., and earn 4X Membership Rewards® points at U.S. supermarkets (on up to $25,000 per calendar year in purchases, then 1X).
  • Earn 3X Membership Rewards® points on flights booked directly with airlines or on amextravel.com.
  • $120 Uber Cash on Gold: Add your Gold Card to your Uber account and each month automatically get $10 in Uber Cash for Uber Eats orders or Uber rides in the U.S., totaling up to $120 per year.
  • $120 Dining Credit: Satisfy your cravings and earn up to $10 in statement credits monthly when you pay with the American Express® Gold Card at Grubhub, The Cheesecake Factory, Goldbelly, Wine.com, Milk Bar and select Shake Shack locations. Enrollment required.
  • Choose the color that suits your style. Gold or Rose Gold.
  • No Foreign Transaction Fees.
  • Annual Fee is $250.
  • Terms Apply.
  • See Rates & Fees