Why aren't 737s or A320s commonly used for transatlantic flights?

Question

Despite newer models of the 737 and A320 families having more than enough range to cross the North Atlantic (and also most of the older models, if they refuel at Gander and\or Shannon along the way; the only one for which this isn't the case is the 737-100, which would require an additional fuel stop in Keflavik, and which is, in any case, no longer in service anywhere), 90% of transatlantic passenger flights are by widebody jets, with 757s accounting for most of the remainder; only 1% of transatlantic commercial flights are by smaller narrowbodies like the 737 or A320.

Given that all A320s and all Next Generation\MAX 737s can fly nonstop between the U.S. east coast and western Europe, and that even the older 737s can fly between the U.S. and Europe if they make a stop or two along the way to refuel, why are the smaller narrowbodies so rare in transatlantic flight, when the prospect of using these smaller, cheaper, more flexible (operationally-speaking, that is, not physically more flexible) aircraft to fly passengers across the Atlantic would seem to be very attractive to airlines, especially low-cost airlines (for instance, Southwest or Ryanair)?

Answer 1

There are many factors that would increase the business cost for taking an operation across the Atlantic/borders:

• ETOPS
• Crew accommodation overseas
• Acquiring airport slots in Europe
• Aircraft cycles (two flights for one destination)
• Cruise speed (being 10-12% slower is huge over long distances)
• Geography, especially latitude.

I will focus on the sixth point, latitude. The comparison of types/distances and geography is a key point.

Looking at FlightAware for JFK to LAX from Sat 07:00AM EDT to Sun 10:43PM EDT, and copying the timetable into a spreadsheet, this is the types breakdown:

Clearly lots of narrow-bodies on that route. Let's do a distances check:

(gcmap.com)

So our best bet is the Gander option, which is 2,043 NM as the crow flies and is comparable to JFK-LAX. Doable, right? Here comes the latitude:

(wikimedia.org)

For most of the time, the polar vortex is strong and doesn't affect the contiguous US that much (watch jet stream forecast animation here). When it weakens, this is when the US weather makes international headlines, and the jet stream drops in latitude. So, for most of the year US transcontinental flights don't face fast headwinds, the story is different for the North Atlantic – compare below:

When the polar vortex is weak, high pressure zones of the mid latitudes may push poleward, moving the polar vortex, jet stream, and polar front equatorward.

Back to the 2,043 NM distance. We'll add 10% to that for diversion and whatnot – a lenient ballpark figure. Now add 100 knots headwind, and the air distance has become 2,890 NM (at cruise speed of 447 KTAS for the A320).

From the A320 airport planning manual, the 2,000 NM permits almost the full payload of 20 tonnes (181 of 186 seats occupied). 3,000 NM on the other hand drops the utilization to 58%.

Our daring airline will now fly half-empty A320s, has to double the fare because of that, put the passengers through a technical stop, and take at least 80 minutes longer – because of the polar vortex. Add the other 5 factors, and it's a no-go for low-cost carriers.

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One of the A321LR's (aka A321neoLR) key solutions is the additional fuel tanks and more efficient engines, giving an initial range of 4,000 NM. This range solves the payload problem, and this kind of specialization is a big deal at the moment, which may render this answer historic in the coming years.

Answer 2

You need to have both a suitable aircraft and a company with the business model to fly the routes.

As to aircraft, only the max8 and a321neo have the range to be really suitable. Westbound in the winter requires additional range that would require a refueling stop in the other models you mention, and that is no way to be profitable on any route. These are both new and in comparatively short supply. The aircraft and operator both need ETOPS ratings.

It is difficult to build a transatlantic business around a particular aircraft if it only just barely has the range for the closest city pair, meaning any expansion requires a second model. Ryanair, Southwest, etc. may not find this attractive.

Widebodies can fly from any US city to any European city. WOW uses the a321neo for the shorter routes, but also has a330s for west coast cities. WOW uses Iceland as a hub, already partway across the Atlantic.

While I think that flying narrowbodies across the Atlantic will grow, just barely good enough for a handful of airlines makes this arrangement unlikely to dominate given the flexibility of the widebody competition.

Answer 3

Two likely reasons:

1. Economics - If your number of flights per day is limited to 1 or 2 and/or you have a limited number of gate slots available, you're better off (i.e., you'll make more money) maximizing the number of passengers per flight. A 737-MAX can carry around 200 passengers in a single-class sardine configuration. A 777 can carry almost 400 passengers in a similarly dense configuration, and over 300 in a more comfortable, multi-class configuration. A 777 is more expensive than a single 737, but much less expensive than two 737s.

2. Comfort - As a passenger, I would not want to fly across the ocean in the aforementioned sardine configuration, and would not buy a ticket to do so. SWA is great for short hops, but anything over a couple of hours starts to get intensely uncomfortable, sometimes painful (I have long legs that start cramping if I can't stretch). You're not going to get a lot of repeat business if your passengers can't walk once they reach their destination.

Answer 4

Some airlines are now starting to do this on routes short enough. Norwegian air now has a route out of Stewart Airport in NY direct to Dublin on a 737-Max8 I flew it late last week and it was quite nice. I believe they have a few others as well direct to Dublin from other northern departure locations in the US.

Traditionally there has always been a fear of flying smaller jets over large stretches of open water and for a long time small twins were not capable of the distances needed.

Answer 5

A good design fundamentals and applications study.

First consideration is how much weight how far. In other words, how one would split fuel load and PAY load. Over time, even pennies saved here would add up. Short haul would carry less fuel and more people.

Next up is wing design and power. The long range plane might gain a few percent in efficiency with smaller, thinner "cruise" wings and fewer turbofans to squeeze out savings in fuel, but not as suited for rapid climbs in shorter, more constricted airspace.

There is also the issue of short field performance. There a larger wing and more power are desirable.

In the end a bit like comparing a thoroughbred with a quarter horse. Versatility vs long distance running.

Not that any other aircraft can fly trans-atlantic, but the most efficient will be in the majority.