In its second-quarter results, Boeing announced its plans to end production of the 747 by 2022. This comes not long after Airbus announced the end of production of the A380, another quad jet aircraft. With both programs counting down their final days, the industry will soon face an all-twin-engine production, for the first time since 1958 when Boeing brought us the 707 was.
This fundamental shift has been purely economic, as twin-engine aircraft outpace the efficiencies of their 4-engine cousins. Let’s take a look at the advantages of a twin-engine aircraft over a four-engine one.
Cabin layout
For this analysis, we compared the most utilized long-haul twin- and four-engine airliners, the Boeing 747-400 and the Boeing 777-300ER. To make the disparity as small as possible, we took real-life cabin layout for both aircraft types from the same airline, British Airways.
The cabin layout of a Boeing 747-400, G-CIVZ is
- First: 14
- Business: 86
- Premium economy: 30
- Economy: 145
Total seats: 275
For the Boeing 777-300ER, it is
- First: 14
- Business: 56
- Premium economy: 44
- Economy: 185
Total seats: 299
British Airways has configured its 747s to focus on business travelers, as it offers 86 seats in business class, 30 more than on its 777-300ERs. However, the twin-engine aircraft has more capacity in economy, both premium and standard. Cumulatively, the triple seven has 24 seats more than the ‘Queen of the skies.’
However, it is worth highlighting that the maximum capacity of the 747-400 is greater than that of the 777-300ER. An all-economy 747 can accommodate as many as 416, while the 777-300ER can house just 368 passengers. Looking at it this way, it’s clear just how business class-oriented the 747-400 fleet is at British Airways.
Costs
The two aircraft types being compared come from two different eras of aviation. The gap between the delivery of the last 747 (1999) and the first 777-300ER (2010) to British Airways is more than ten years. This decade brought about a great deal of innovation in the industry. Bigger engines, new components, modern designs; all with the aim of increasing efficiency, lowering fuel burn, and making flying more profitable for the airlines. Clearly, it succeeded.
The Boeing 747 burns approximately ~10.5 tonnes of fuel an hour in cruise, while the 777-300ER burns ~7.5t of fuel per hour while cruising; almost 30% less.
While the triple seven has brought significant fuel-burn reductions, the crucial leap forward has been achieved with the A350 and 787 families, which reduced the fuel consumption even further, to roughly ~5.5 tons per hour of flight. The Queen of the skies burns twice the amount of the newest airliners.
Route example profitability
To visualize profitability differences, let’s compare London Heathrow to New York JFK. Ticket prices in around two weeks from today are:
- First: £9,500
- Business: £1,740
- Premium economy: £1,215
- Economy: £370
As of today, the price of aviation fuel per barrel is £35.3. BA’s load factor in 2019 averaged around 80%; hence we assumed an 85% load factor in the economy class, 50% in the first class, 60% in business, and 75% in premium economy.
Under these assumptions, the revenue achieved by the 747 is around £800,000, while for the triple seven, it is £980,000 or 22.5% more.
A jumbo jet flying from London to New York burns approximately 82,353 liters of fuel or 518 barrels with a total cost of £18,285. The cost for a triple seven is approximately £3,500.
Assuming all other costs are constant and not including the cargo revenue, we can see that a Boeing 777-300ER creates the possibility for greater revenues at a lower cost.
A more technical comparison of both aircraft types can be found here.