Boeing may be close to launching a major upgrade to its 737 single aisle jet family if hints it dropped at the delivery ceremony for No 6000 to come off the line this week mean anything.

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The 737 is the most flown jet ever and has been around since 1968 although technically everything in the early versions has been refined or replaced to make it more efficient to build and operate.

But will those incremental improvements lead to something bolder, and soon?

Boeing has another 2200 of the current NG series of 737s on order, and has already delayed its much anticipated replacement with an all new design until around 2020.

The big factor that has suddenly come over the horizon is the GTF or geared turbo fan engine. Never mind the technicalities, a GTF could cut fuel consumption and emissions by at least 12.5 %. In a motoring analogy, it’s like being able to better match engine speed to power need.

The emphasis in recent tweaks to the current NG series 737s has been on their green street cred. We’ve even seen them flown with a blend of algae grown octanes, which is a critical breakthrough above and beyond octanes derived from plants which can displace food crops and have featured in earlier biofuel trials.

So in any connect the dots analysis, Boeing is undoubtedly looking at better engines, lighter airframes and fuels (further down the track) that liberate less fossilised carbon.

On routes like Sydney-Melbourne, where around 40% or more of the fuel burn happens just holding and taxying to takeoff position, and in climbing to altitude, the GTF technology comes to the fore with even bigger savings.

There is a ‘virtuous circle’ in airline design in which reduced fuel loads mean reduced takeoff weights which require less structural weight in the airframe and in turn enhance the original reduction in fuel needed to move X tonnes Y kilometres.

Assuming Boeing is also looking at lighter construction techniques as well as better fuel savings from the engines then some seriously good improvements can be achieved all around.

There is a slight problem with GTF engines in that they have a ‘fatter’ or wider cross section, and the 737 already sits pretty close to the ground compared to its rival A320 family.

But this is where the hints from Boeing point to something cooking in Seattle. A few weeks ago Boeing went to the trouble of declaring that a GTF engine could be accommodated on the 737s.

Why did it say that? A reasonable guess would be that it has already finalised a design change that gives the 737 more ground clearance with a new undercarriage design. And that is something that involves so many changes in the body of any airliner that you would only contemplate doing it if you knew you were already going to sell at least another 2000 of them.

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Peter Fray
Peter Fray
Editor-in-chief of Crikey
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