One variant about to enter service and another in flight testing – a lot is happening with the Boeing 737 MAX. Nigel Pittaway provides an update on the programme
BOEING 737 MAX
Boeing’s 737 MAX programme continues to execute on or ahead of schedule and recent milestones include the completion of the fiight test programme for the 737 MAX 8, the initial variant, and the first fiight of the larger 737 MAX 9.
In addition, the first production aircraft was due to be delivered to launch customer Malindo Air in May and will be in service by the time these words appear in print. The company is also nearing a decision on when to proceed with the proposed 737 MAX 10X variant and it said it is engaging with likely customers.
The 737 MAX programme is designed to refresh Boeing’s best-selling 737 design and to realise significant fuel-burn advantages over the earlier Next Generation (NG) (737- 700 to 737-900ER) and ‘classic’ (737-300 to 737-600) airliners.
The programme was officially launched in 2011, and by the middle of April Boeing reported that it holds more than 3,700 firm orders from 86 customers around the world. Ahead of the first delivery, AIR International spoke with the 737 MAX Chief Project Engineer and Deputy Programme Manager Michael Teal, to gain insight into the programme to date and to find out more about Boeing’s future plans for the family of aircraft.
MAX Programme Overview
Teal joined the 737 MAX programme as Chief Project Engineer when it was first launched in August 2011 and said there were two principal rules followed, in terms of fuel burn guarantees and aircraft production. These rules dictated how much the basic design would change from the NG family then (and still) in production.
Teal remembered: “It had to meet the customer requirements for improved fuel burn, so the mission was that we were just going to work on the components that improved the fuel efficiency of the airframe, so we limited the work statement to only that which would improve fuel burn.”
The second requirement was to ensure the incorporation of the MAX family into the current 737 final assembly facility at Renton could be completed flawlessly and accomplished without affecting NG production. “So from day one we had the requirement of the production system overshadowing the design,” Teal said.
Changes from the NG include replacement of the CFM International CFM56-7 engines with LEAP-1B power plants and aerodynamic improvements to the wings and fuselage, the most noticeable of which are the redesign of the tail cone, resulting in the deletion of the large vortex generators between the horizontal stabiliser and fin, and the installation of what Boeing calls its Advanced Technology split winglets.
Teal said: “Between the improvements we made with respect to the winglets, the engines and the tail, we’re now delivering 14% better fuel burn than the NG is delivering today.”
Other changes include the replacement of the NG’s five fiight deck displays with four larger units, similar to those adopted for the 787 and 777X, the move to flyby- wire spoilers and replacement of the troublesome engine bleed air system with a digital system, capable of minimising the amount of air being tapped off the engines for anti-icing and cabin air conditioning and pressurisation.
Teal said: “Between the classic, which first delivered in 1988, to the NG, which delivered in 1998, there’s about a 13% improvement in fuel burn efficiency per seat. Since then, Boeing has continually improved fuel burn – in 2001 we added winglets, we significantly reduced weight by introducing carbon brakes and in 2011 we improved both aerodynamic and engine performance – improving the NG about 6% over the initial deliveries in 1998.
“The MAX is an additional 14% beyond the NG we are currently delivering, so a reduction in fuel burn of over 20% over the first deliveries. With the same fuel capacity, this airplane will have in the neighbourhood of 400–500 nautical miles [740-926km] more range, meaning airlines can fly the airplane in their existing market space with significant improvement in fuel burn, or they can open up new markets enabled by the additional range capability of the airplane.”
From the outset, the MAX programme was designed to deliver a family of differentsized aircraft, in much the same way that the 737-700, 737-800 and 737-900ER do today. From smallest to largest, the family will consist of the MAX 7, MAX 8 and MAX 9. A ‘super density’ version of the MAX 8, known as the MAX 200, is also being developed for low-cost carriers (LCCs), and Boeing is planning a MAX 10X, should there be sufficient interest from customers for an even larger aircraft.
The firm family configuration was determined in 2013 and design of the first variant, the MAX 8, began in 2014. The MAX 8 is the equivalent to the 737-800, with between 162 (two-class configuration) and 184 (single-class configuration) seats, and the first aircraft made its maiden flight from Renton on January 29, 2016.
The initial aircraft was joined by three further MAX 8 test aircraft in a flight test campaign that finished in February, paving the way for Federal Aviation Administration (FAA) type certification, which was awarded on March 9 this year.
Teal said: “We have now received our amended type certificate from the FAA and the European Aviation Safety Agency and we are now working with foreign regulators to get validation from them as well, so we can deliver the airplane throughout the world.”
In terms of timeline, the next family member is the MAX 9, capable of accommodating between 180 and 204 seats, three rows longer than the MAX 8 and the same body length as today’s 737-900ER. The first aircraft rolled out of the factory on March 7 and made its initial flight five weeks later, on April 13. Deliveries are expected to begin in 2018.
Following the MAX 9, the smaller MAX 7 (138–172 seats) will begin final assembly at Renton in the fourth quarter of this year and is due to fly in April 2018.
Teal said: “The engineering for both the MAX 7 and MAX 200 is complete. The MAX 200 is really the same airplane as the MAX 8, but we’ve added a mid-entry door to allow customers to put up to 11 more seats in. It’s designed for low-cost carriers who really want to carry as many people as they can.”
The MAX 200 was requested by several LCCs, including Ryanair and Vietjet. Teal continued: “The MAX 8 has an [emergency] exit limit of 189 passengers and, with that number you would typically have a 31-inch [787mm] seat pitch in a single-class configuration. There’s also a break point at 200 passengers where, if you exceed that number, you have to add another flight attendant.
“With a MAX 200, you’re putting an extra door in, moving the seats to a 28-inch [711mm] pitch and enabling an airline to put 200 passengers on an airplane that effectively weighs the same as the MAX 8. So airlines that are willing to take that 28- inch seat pitch, the best fuel burn machine for them would be the MAX 200 with 200 passengers, ensuring that they only need four flight attendants.
“Only time will tell what percentage of the marketplace will go that way, but if you’re looking for an airplane that maybe doesn’t have the same range capability [as a MAX 8], but has that superior fuel burn economics with 200 seats, the MAX 200 is the airplane for you.”
Boeing will not discuss a specific timetable for roll-out and first flight of the MAX 200, but said the first delivery will occur in 2019.
The final variant is the proposed MAX 10X, which, on present thinking, will be 66 inches [1,676mm] longer than the MAX 9, but Boeing will not settle on a firm configuration until the end of this year. Teal said the aircraft is being offered to customers, however, and that Boeing will formally launch the programme when it determines that interested airlines are ready to buy it, with deliveries predicted in the 2020 timeframe.
He predicted: “The 10X will have a range equivalent to the 737-900ER today and I am optimistic that we’ll make significant inroads into the LCC market space. We’re adding two more seat rows over the MAX 9 and 737-900ER, up to 12 passengers, so those airlines looking for the range equivalent to the 737-900ER, and then adding two more seat rows, will put an airplane in the marketplace with a low seat-mile cost and bring in more revenue because of those extra seats.”
Flight Test Programme
The four MAX 8 test aircraft finished the flight test campaign in February and are currently being refurbished to production standard for delivery to customers. Boeing will not publicly discuss who the customers will be, but a Boeing spokeswoman said that the first MAX 8 delivered will not be one of the former test fleet.
Each of the four aircraft was allocated different duties in the flight test campaign, which culminated in airline-style functionality and reliability (F & R) testing, prior to FAA certification.
The first aircraft to fly (N8701Q, Boeing reference 1A001, c/n 42554) was the basic aerodynamic configuration test aircraft, which conducted stability and control and flutter testing, before completing its programme in September 2016.
The second MAX 8 to fly (N8702L, 1A002, c/n 36989) had production standard LEAP-1B engines installed and carried out performance testing, including fuel mileage determination, climb and landing performance testing and high-altitude trials, undertaken at La Paz in Bolivia.
Aircraft number three (N8703J, 1A003, c/n 42556) was the systems performance test aircraft, which tested all of the aircraft’s systems, including autoland trials. The majority of systems testing were performed by aircraft two (engine) and three (airframe systems).
The final test aircraft (N8704Q, 1A004, c/n 36988) was in a standard airline configuration and was used for the F & R testing, which took it as far afield as Yakutsk in Russia, for cold soak testing, and Darwin in Australia, for extended twin operations hot/humid trials. It was this aircraft that also visited the UK in July 2016 to attend the Farnborough Airshow.
Teal reported: “The completion of the flight test programme was the F & R testing, which is a regulatory requirement that we put the airplane through 300 hours of demonstrated performance with FAA representatives on board and it performed flawlessly. We’re very happy with the flight test programme, we were done in February and now all four airplanes are getting ready for refurbishment and go back into the customer’s fleet.”
Throughout 2017 and 2018, 737 MAX 9 testing will be undertaken by two flight test aircraft, but so far details of the MAX 7 programme have not been announced
Teal predicted that production of the 737NG at Renton will end in 2019 and that all aircraft delivered after the middle of that year will be variants of the MAX family: “The MAX 8 is at the heart of the market and we expect that approximately 75–80% of sales will be shared between the MAX 7 and MAX 8.
“The MAX 9 provides for growth in the heart of the market where, if airlines have a couple of high density routes that need more seat rows than the MAX 8, the MAX 9 is a great family member to buy. We’re seeing airlines buy both MAX 8s and MAX 9s, to have that combination and density for the times of year when they need it. We expect the MAX 9 and MAX 10X market to be somewhere between 15 and 25% of the family market.”
Finally, Teal said he doesn’t see the MAX 10X competing with Boeing’s future ‘middle of the market’ aircraft plans: “The ‘middle of the market’ is really above the MAX family, but below the 787, so I don’t expect the 10X to compete with that airplane. I think those two airplanes both serve their needs and there’s a place in the market for both.”