Returning to the subject of range limits, Mr Rosenschein said that they can also determine how often these incidents happen.
“These incidents are common when an aircraft is operating close to or at maximum range where the WAT limits are critical or en route headwinds are strong,” he said.
“When aircraft are operating well within their maximum range and departing an airport with a long runway then these incidents are extremely rare.
“Most modern aircraft have very good performance and range capabilities, but some airlines operate their aircraft on long routes close to their aircraft maximum range and that is when these incidents are most common.”
Assoc Prof Sameer said the frequency of such cases varies depending on airline procedures, routes and weather patterns.
Are there other solutions?
Instead of offloading luggage, one option is for planes to carry extra fuel – but this has its limitations.
“Regarding fuel supply, airlines calculate fuel loads based on various factors, including the expected weather conditions,” Assoc Prof Sameer said.
“Carrying extra fuel for every flight would increase operational costs and reduce efficiency.”
Mr Waldron expressed a similar view.
“You can carry more fuel, but of course, the issue with carrying (more) fuel is there is certainly a limit to the amount of fuel that the aircraft can carry,” he said.
“The other issue with carrying fuel is that you’re burning, early in the flight, you’re burning lots of fuel just to carry that extra fuel to the destination.
“Fuel actually weighs a lot as well, so getting it off the ground and into the air, it’s a big expenditure, and at the extreme ranges of commercial aircraft – or any aircraft really – the performance of the aircraft really starts to fall off. So the benefit you get from carrying that extra fuel starts to fall off quite sharply as you get very deep into a long flight.”
Fuel is also one of the biggest costs, if not the single biggest cost for airlines, Mr Waldron said, so adding more fuel could be a cost issue for carriers.
Mr Rosenschein, too, spoke of the limit to how much fuel an aircraft can carry and highlighted some alternatives to offloading baggage.
“The maximum amount of fuel that can be loaded is determined by the size of the fuel tanks and the air temperature of the departure airport – warm fuel expands therefore reducing the weight of fuel that can be loaded,” he said.
“Offloading baggage or cargo may be the only two operational possibilities on some flights.
“Landing en route to refuel is another option but (this) takes time and is costly.”
Other options include reducing the number of passengers and taking off later in the day when the departure airport is cooler, or when there might be a higher take-off headwind forecast.
Mr Waldron said that some airlines, particularly when travelling to destinations that are further away, will reduce weight by leaving a few seats at the back of their planes empty.
Are passengers compensated?
Passengers are typically compensated for the inconvenience of having their luggage stuck at their point of departure.
“Passengers are usually compensated for delayed luggage according to the airline’s policies, which may include providing essentials like toiletries or clothing and reimbursement for expenses incurred due to the delay,” said Assoc Prof Sameer.