Boeing Has Revised The 737 MAX 10’s Main Landing Gear

On Friday last week (22/11/19) Boeing heralded its latest innovation with muted celebration. So arrives the next MAX variant, complete with a “shrink link” redesign of its main landing gear.

MAX 10 in flight
Boeing’s innovative landing gear design features a shrink link coupling. Photo: Boeing

Boeing has unveiled its latest offering to the aviation industry: the 737 MAX 10. The manufacturer hopes the type will pass with flying colors all of the system checks, engine runs and regulations needed to fly. Writes Boeing in its press release of November 22nd, the type is expected to fly “next year”.

The MAX 10 currently has more than 550 orders and commitments from more than 20 customers worldwide. United is its biggest buyer, according to OMAAT, with 100 of the planes on order. Flydubai, Lion Air and VietJet Air have more than 50 MAX 10s on order.

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We have contacted Boeing for further comment.

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MAX 10 landing gear

The MAX 10 is 66 inches longer than the previous variant, the MAX 9. By extending the fuselage thus, Boeing was able to provide a plane that can potentially seat up to 230 passengers. But that extra length would necessitate longer landing gear since, if the gear remained unchanged, the rear fuselage of the aircraft would impact the runway at rotation.

Boeing B737-10
Longer than the MAX 9, the -10 requires a longer undercarriage. Photo: Boeing

Hence Boeing sought to add longer main landing components without changing the interior wheel well to accommodate the larger gear. This it did, writes Flight Global, by the design of a “semi-levered main gear design”.

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Innovative

To have created a taller gear would have meant commensurate changes to the interior of the aircraft. Boeing wanted to avoid making any changes and preferred the idea of retaining commonality between other MAX types.

Boeing MAX 10 in flight
Boeing keen to avoid expensive changes to the hull of the MAX 10. Photo: Boeing

In August of this year, Boeing revealed it had begun work on a shrink link: a steel compressing mechanism which pulls the inner cylinder as the gear retracts. The gear extends 241mm (9.5in) upon rotation during the take-off run and provides the required clearance of the rear fuselage.

By designing this “shrinking” mechanism, Boeing was able to avoid gear well changes and retain the same wheel design seen of other types of the MAX family. Gary Hamatani, Chief Product Manager for the 737 MAX told FINN,

We wanted to preserve commonality in the MAX Family. We needed to get the landing gear back into the unchanged wheel well of the MAX 8 and 9.”

The engineering team “knocked it out of the park” with the design, added Hamatani.

Dissenters

Despite Boeing’s assurance that the new landing gear design is the same as that of the other MAX types, some industry observers see issues arising from the addition of a weak link that is already seen of various types of A330 and the B777.

In particular, the addition of the connection point will lead to a number of problems associated with links along the mechanism. These include the likelihood of corroded components due to improper lubrication.

There is still doubt about whether the MAX 10 will fly in any case, regardless of the posh new undercarriage. The type came about in the wake of Airbus’s success with the A321neo, but its range is under-competitive. Furthermore, OMAAT notes that, unlike the A321neo, there are no plans to extend the range of Boeing’s new type.

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Matt

Not an aerospace engineer but as an engineer this gear change sounds like another fudge, adding another potential point of failure to continue selling a 60 years old aircraft design… very sad for a company that had once dominated in innovation and quality.

K.P.

its on the Airbus A330 so might want to calm down a bit, don’t get your sponsors upset with you

Matt

I am an american so I have a huge stake in Boeing success. That doesn’t translate to sit and cheer and cover up for the max fiasco. Nevertheless, I confess not knowing that this was done in other airplanes…. thanks for pointing that out….

Bryce
TonytTDK

Anything which complicates an existing & effective system, increases it’s potential to malfunction.
Boeings own MCAS disaster is a prime example of this.
The aircraft maker is trying to get around a problem which it has created for itself by now making the B737 as long as the original B707, but still with the B737 undercarriage.
I will be amazed if there weren’t either, a bigger proportion of undercarriage malfunctions in this new model,
or
a substantially increased amount of maintenance & inspection required, to mitigate the design……
& there’s a good chance it will actually be Both of those things.!!!

Norman

Are there any technical articles on the design and its concerns suitable for reading by the average Joe Blogs ?

Bryce

Based on how this extending gear works, I wouldn’t be surprised if it regularly jams…just like the problematic 737 rudder in the 90s.
There are some photos of it today on FlightGlobal.

Bryce

“The manufacturer hopes the type will pass with flying colors the system checks, engine runs and regulations needed to fly.”
I wouldn’t hold my breath on that one! On Reuters last weekend, two new pieces of trouble for the MAX re-certification process:
– An e-mail from an engineer at the Canadian regulator telling Boeing that MCAS would have to be removed from the MAX in order to get the plane ungrounded;
– Reports from airframe suppliers that the MAX probably won’t be recertified before summer 2020.

Trent

Good for Boeing.

But here is the issue. The 737 is so compromised by changes needed to stay relevant, and this is just another example.

Could this work without a hitch? Sure. But the “MAX” updates don’t have a good track record so far.

charlie murray

In 60 years time I hope my Jeep doesn’t drive and handle the same as the one I have now.

Yes it’s used on other types of aircraft but other types of aircraft are also flying withe the same types of engines But they don’t need a MCAS to try to stop it falling out of the sky because the C of G is all to cock.

Stack them high sell them cheap can only work for so long

Frank

The engineering team “knocked it out of the park” with the design, added Hamatani.

I’m wondering what was said at the time MCAS was rolled out by the software dept.?

Hein

Nothing was said! Therein lies the problem….

Mark Thompson

Aviation Week had an article two years ago covering this news. The technology is based on fighter jet designed on aircraft carriers.

Bryce

That’s the basic design…but what about the implementation? How many shortcuts were taken there?
Example: the pickle forks on the 737 NG are “based on” those in other Boeing aircraft…but someone at Boeing still managed to screw up 😉

Phil Mc Shane

If I ever arr at an airport and see ANY Max737 to fly me to my destination I will refuse to board – and want full compensation!! I know nothing about aviation etc etc but just to think of all those poor souls that lost their life in 2 of these aircrafts is enough for me 😢

Kat Spencer

You should read more so you don’t sound so ignorant. Refuse to board and request full compensation? Yea ok… Good luck!

Daryl Locklear

Mr. McShane, you are not ignorant, as K. Spencer erroneously suggests. One can make sure that your aircraft is not a Boeing 737 MAX 8, pay for a ticket, arrive at an airport and – voila! – the airline has substituted a 737 MAX 8 for your flight. You could refuse to board and demand compensation for the ticket that you paid for. Many credit cards have trip cancellation insurance – for whatever reason – as a perk on the card. Check your cards. You can also purchase trip cancellation insurance before your flight. Watch out for any connecting flights.… Read more »

K.P.

God I just love the haters hashing the same old crap over and over. Really , get some new crap and keep drinking that AIrbus Kool-aid that tells you they are so much better, they haven’t designed anything in the last 3 decades of aviation only copy Boeing designs, unless you want to count the A380 and A400M, how much those flops cost the average European tax payer…. oh yeah ,, woohooo go LOSERS

Matt

Boeing is at it again. Trying to make a completely obsolete 1967 designed 737 work in the modern world? How about building a complete new aircraft that will accommodate the bigger Leap engines and a longer landing gear, instead of more band aides? The prior CEO started the ball rolling on the destruction of this once proud company, and now the current dumb ass continues the pattern. All about stock price with Boeing. Safety LAST! Now a Max 10 tail dragger, once the lift kit on the new gear fails. Boeing is run by morons!

Shapes

The max family are complete bodge jobs to cover up a 60 year old design that Just won’t accommodate bigger engines or a longer fuselage. It’s an absolute joke that they are still trying to push forward with this frankenstein of a plane, but that of course is because they have nothing else to sell.

Shapes

https://youtu.be/F4IGl4OizM4

This is the link that explains about the fix and why it was needed on this mess of a plane. Its basically to push the fuselage up to prevent tail strike on take off, if it malfunctions it could result in the undercarriage failing to extend or retract, plus the forementioned tail strike. A wheels up fatal crash landing would not be good PR.

Shapes

I would also think that the pickle forks in the max are exactly the same as in the NG and will be prone to cracks in the future.

Bryce

I’ve read elsewhere (Leeham) that the pickle forks on the MAX are different to those on the NG. Of course, “different” doesn’t necessarily imply “problem-free”…

Shapes

I see no reason why they would be any different, that was the whole point of the max, its exactly the same airframe but with larger engines, and now an extended airframe with the undercarriage “fix”.
I can easily see why boing would want to play down the prospect of future problems for the max if they can pressure enough people to get it back in service.

Timo

This is 737-10, they have dropped the MAX-text away. What do you think about the new name and what does it mean? Here are some proposals:

737 NG (Not Grounded)
737 M (MCAS included)
737-10 (10 less capasity than a321 neo)

Josh

Actually the only design which is not patched/updated and includes modern technology from day 1 is the A220 (ex cseries). The A320 was luckily designed with an already large turbofan engine (CFM 56), thus having a longer landing gear, and had fly-by-wire technology from the beginning (not mentioning a wider cabin and ability to take containers). It is true that a 60 year old design will never be efficient, the CAD systems were hardly a reality in the 60’s.