Boeing 737MAX

Airbus chief operating officer customers, John Leahy cited his "reliable sources" at airlines and suppliers who have said Boeing's clean sheet New Small Airplane (NSA) wasn't fully off the table as the US airframer works to evaluate the configuration of its re-engined 737 Max.

"The clean sheet of paper team has not been dismantled in Seattle and...people are concerned as it takes longer and longer to get the Max into a condition [where] it can be competitive with the Neo that perhaps they would go back to - what until a couple months ago they were saying was their preferred choice - a clean sheet of paper airplane," said Leahy during a presentation in Washington, DC on the Airbus global market forecast for North America.

Boeing disputed Leahy's claim, saying that it was "absolutely" 100% committed to building the 737 Max, for which the company holds over 700 commitments from nine customers after it was officially launched in late-August. The airframer expects it first firm 737 Max order before the end of the year.

Boeing said its normal product development activities are on-going and the company is "always looking to what's next" for new programmes, architectures, production systems, technologies, configurations and markets.

Leahy also said that it would "not be a disaster" if Boeing switched back to a clean-sheet narrowbody to take on the A320neo, which will enter service with Qatar Airways in October 2015, citing the cushion of more than 1,450 firm orders and commitments for the re-engined A320 jet, including 1,200 firm orders.

Leahy said empty weight growth of the 737 Max, which he said could top 2.3t (5,000lbs), has eaten into the fuel burn improvement from its 173cm (68in) CFM International Leap-1B fan, which he claimed would only generate an 8% fuel burn improvement over today's 737.

Leahy also said the 737 Max will have a 7.5-8.5:1 bypass ratio compared to an 11:1 and 12:1 ratio on the A320neo's 198cm (78in) CFM Leap-1A and 206cm (81in) Pratt & Whitney PW1100G engines, respectively.

Airbus said its A320neo with 150 seats claims a 7% per seat fuel burn advantage over the 737-8 [re-engined 737-800] with 157 seats, while Boeing has said its 737-8 with 162 seats holds a 4% per seat fuel burn advantage over the 150-seat A320neo and 16% over today's A320.

Boeing said its 737 Max will garner 10-12% better fuel efficiency over today's Next Generation 737 family. The US airframer also claimed current model 737-800s hold a 2% operating cost advantage over the A320neo.

Boeing expects to achieve firm configuration for its 737 Max in 2013, four years ahead of its 2017 service entry.

Leahy claimed every 2.5cm (1in) of fan diameter translates to .5% of specific fuel consumption improvement (SFC) and the 28-32% larger fans on the A320neo compared to today's A320 family aircraft correlate to a 7% SFC improvement, while an additional 7% will come from the engine's core. About 1% additional SFC comes from the integration of the engine's new pylon and nacelle.

The total combination of the core, fan and integration gives the A320neo a 15.3% improvement in SFC, while its Sharklet wingtip treatments will deliver a further 2.4% SFC improvement over 1480km (800nm) stage-lengths, said Leahy.

Overall, the 1.6t (3,500lb) increase in the empty weight of the aircraft and the added drag of the larger Leap-1A fan would increase fuel burn by 2.7%, resulting in the A320neo's 15% improvement over today's CFM56-powered A320.

DALLAS, Dec. 13, 2011 – Southwest Airlines is once again leading the industry by teaming up with its longtime partner to become the launch Customer of Boeing's new 737 MAX aircraft. Southwest is the first Customer to place firm orders for the new, more fuel-efficient 737 MAX, and the Company also will become the first airline to accept delivery of the new aircraft in 2017. As the launch Customer of the 737 MAX, Southwest extends its legacy with Boeing as the 737 launch Customer for the -300, -500, and -700. The 737 MAX is the new-engine variant of the world's best-selling airplane, building on the strengths of today's Next-Generation 737 (737NG) technology, and is powered by CFM International LEAP-1B engines. For more information, visit: www.swamedia.com.

In its ongoing effort to improve fuel efficiency while extending its record of unparalleled Customer Service and profitability in the airline industry, Southwest has placed a firm order for 150 Boeing 737 MAX airplanes, with the first delivery scheduled in 2017. The Company also expanded its current order book with Boeing for 58 additional 737NG aircraft. These new orders join an existing firm order book of 142, bringing Southwest's total firm orders with the Boeing Company to 350 for 2012 through 2022, which are intended to predominately serve as replacement aircraft as the airline continues the modernization of its fleet.

"Today's environment demands that we become more fuel-efficient and environmentally friendly, and as the launch Customer of the Boeing 737 MAX, we have accomplished both," said Gary Kelly, Southwest Airlines Chairman, President, and CEO. "We are teaming up with our friends from Boeing to lead the industry in a way that makes both our Shareholders and our Customers proud to associate with Southwest Airlines. Today's announcement will allow us to maintain our position as a low-cost provider in the years ahead."

"We are enthusiastic about our fleet modernization plans, and especially about becoming the launch Customer for the Boeing 737 MAX," said Mike Van de Ven, Southwest Airlines Executive Vice President and Chief Operating Officer. "The much improved fuel efficiency of the 737 MAX will enable us to improve our fuel costs, as well as our environmental performance, with great comfort and reliability to offer to our Customers."

Van de Ven continued, "Overall, we expect the superior economics of our fleet modernization plan to meet our 15 percent pretax return requirement and provide substantial flexibility to manage our growth in a variety of economic conditions over the next decade. Additionally, these new aircraft will enhance the Customer Service offering with the new Sky Interior."

The 737 MAX with LEAP-1B engines will reduce fuel burn and CO2 emissions by an additional 10-11 percent over today's most fuel-efficient single-aisle airplane. It will have the lowest operating costs in the single-aisle segment with a seven percent advantage over its competition.

The 58 new 737NG firm orders include the exercise of 25 previously existing options. The Company has substituted -800s for all -700 737NG deliveries scheduled for 2012 and 2013 in addition to a portion of its 2014 deliveries. For the 737 MAX order, the Company has flexibility to accept MAX 7 or MAX 8 deliveries. The revised order book also includes 78 737NG options and 150 737 MAX options, bringing

total option positions from 2014 through 2027 to 242. Additional information regarding the Company's 737 future delivery schedule is included as an accompanying table.

On 12 December it set a list price of $77.7 million for the 737 Max -7, $95.2 million for the -8 and $101.7 million for the -9 variant.

Boeing also released list prices for the re-engined Max family. The 737-7 Max is priced at $77.7 million, the -8 shows a price of $95.2 million and the -9 model has a $101.7 million list price.

Current list price for the 737-700 is $70.9 million, $84.4 million for the -800 and $89.6 million for the -900ER variant.

ccording to Aspire Aviation‘s sources at the airframer, the larger CFM Leap-1B engine is going to feature a more “squash-bottomed” engine nacelle than today’s CFM56-7BE engine to house the customised core while maintaining a sufficient amount of ground clearance, which is at 17 inches on the existing 737 NG aircraft, cautioning the bottom of the engine nacelle will look considerably more flattened than artists’ renderings released so far.
Engine-maker CFM International could not be reached for commenting on the shape of the Leap-1B’s engine nacelle at press time.
A noteworthy point is, in the meantime, Boeing’s regional director of product marketing Anita Polt said the nose-gear extension will be “no more than eight inches, but probably less than that” while adding the 787-styled tail cone will contribute 1% of fuel burn improvement to the 10%-12% fuel burn savings delivered by the 737 MAX, flightglobal Pro reported.
Meanwhile, Southwest’s significant influence on the re-engined narrowbody aircraft’s development is likely to see Boeing adhere to its minimum change philosophy indicated by senior company executives, a painful lesson learnt on the beleaguered 787 Dreamliner programme resulting in more than 3 years of agonising delays and US$18 billion of gross inventory in addition to US$9.7 billion of deferred production cost (“Boeing posts stellar 2011 third-quarter profit amid 787 & 747-8 concerns“, 1st Nov, 11).
“We tried to stay with a commonality theme. We wanted this to be as much commonality as we can compared to the 737 NG. Of course, we wanted to improve upon efficiency and productivity around the airplane, so we have been working closely with Boeing and it is every much an iterative process. Our intention is to play a very important part in the development of the airplane right up through entry into service,” Southwest Airlines senior vice president (SVP) of technical operations Brian Hirshman conceded.
Notwithstanding this and make no mistake, a number of studies currently undertaken by the Chicago-based airframer, including the raked wingtip and a higher maximum take-off weight (MTOW) to boost the 737 MAX’s payload/range capability, especially on the largest variant 737 MAX 9, are still ongoing.
Despite further improving the re-engined aircraft’s fuel burn by less than 1% while enhancing its payload/range capability, Aspire Aviation‘s multiple sources cited the operational constraints at US airports and Southwest’s launch customer status as reasons that a raked wingtip similar to the one found on the P-8A Poseidon anti-submarine and reconnaissance aircraft, is unlikely to find its way to the final 737 MAX configuration.
Sources pointed out that the blended winglet-equipped Boeing 737-800 with a wingspan of 35.8 metres (117.5 ft) is already at the upper limit of US Federal Aviation Administration (FAA) gate type A, and adopting a raked wingtip such as the P-8A Poseidon’s one with a wingspan of 37.64 m (123.6 ft), will cause the 737 MAX to be categorised as Airplane Design Group (ADG) 4 aircraft instead of ADG Group 3 aircraft, thus demanding gate type B at US airports and “pushing the envelope” too far which will prompt costly airport modifications.
The FAA defines Group 3 aircraft as those with a wingspan between 79 and 118 feet whereas the Group 4 aircraft as those with a wingspan between 118 and 171 feet.
The same sources also added Boeing wants the International Civil Aviation Organisation (ICAO) to lift its ADG Group 3 limit by 2 metres (6.56 feet) to accommodate the raked wingtip, although it is unclear on ICAO’s response and its implications on the 737 MAX’s final configuration.
Other studies, such as a variable area fan nozzle (VAFN) which promises a fuel burn reduction of up to 2% and is going to be tested on board an American Airlines Boeing 737-800 in August or September 2012 as part of the continuous lower energy emissions noise (CLEEN) programme, as well as a passive, retrofittable hybrid laminar flow control (HLFC) which yields a 0.5%-1% reduction in drag, are still undergoing evaluations and a decision is not expected anytime soon.

Image Courtesy of Boeing
The contentious fuel burn debate
When Airbus’ chief operating officer (COO) for customers John Leahy presented at the Credit Suisse Aerospace and Defense conference on 31st November, Leahy challenged Boeing’s claims that the Boeing 737 MAX 8 will have a 4% lower fuel burn per seat and a 7% lower total operating cost, including aircraft procurement cost and maintenance cost, this has further intensified the contentious fuel burn debate between the two transatlantic rivals on which one’s aircraft is the most fuel efficient one.
Leahy contended that the existing 150-seat A320 without sharklets burns about the same amount of fuel as the 157-seat 737-800 with the CFM56-7BE engine on a 800 nautical miles (nm) mission, whereas Boeing countered by saying the 162-seat 737-800 burns 7% less fuel per seat than a 150-seat A320 on a 500 nm sector. Airbus also claims the 124-seat A319 burns 1% more fuel than the 124-seat 737-700 on an 800 nm sector, whereas its 185-seat A321 burns 3% less fuel than a 173-seat 737-900ER (extended range) airplane. Boeing refuted this claim, saying its 180-seat 737-900ER is 11.3% and 9.5% more fuel efficient than a 180-seat A321 on a trip-fuel and seat-mile fuel basis on a 500 nm sector, according to an AirInsight report titled “Comparing 757 Replacements”.
Similarly, Airbus claims the 150-seat A320neo (new engine options) will be 7% more fuel efficient than a 157-seat 737 MAX 8, whereas the 124-seat A319neo and 185-seat A321neo are 6% and 11% more fuel efficient than the competing 124-seat 737 MAX 7 and 173-seat 737 MAX 9, respectively. Boeing countered that the 162-seat 737 MAX 8 will have a 4% lower fuel burn per seat and a 7% operating cost advantage versus the 150-seat A320neo on a 500 nm mission, while Boeing Commercial Airplanes (BCA) vice president (VP) in business development and strategic integration Nicole Piasecki reiterated that “the 737 MAX 9 [has] about 5% better operating economics for its seat-mile economics and its trip costs will be about 6% better [than the A321neo]. Its operating economics are significantly better”.
In addition, Airbus chief operating officer (COO) customers John Leahy explained the rationale behind the 15% fuel burn reduction of the a CFM Leap-1A-powered A320neo versus a CFM56-powered A320 aircraft, with both 7% reductions in specific fuel consumption (SFC) brought by an improved core and 32% more fan area, as well as a 1% reduction from powerplant integration plus a 2.4% reduction in fuel burn resulted from the introduction of sharklets, which is slightly offset by a less than 2 tonnes increase in maximum empty weight (MEW) and extra drag that negated 2.7% of the total fuel burn saving.
In contrast, the CFM Leap-1B engine will bring a 10% fuel burn reduction to the 737 MAX’s engine specific fuel consumption (SFC), consisting of a 6% reduction from a customised improved engine core, a 3.5% reduction in SFC from 24% more fan area and another 0.5% reduction from powerplant integration. However, a 0.5% reduction in fuel burn resulting from aerodynamic improvements is insufficient to offset the 2.5% fuel burn penalty resulting from the extra maximum empty weight (MEW) and extra drag, thereby resulting from an overall fuel burn improvement of 8% of the 737 MAX 8 versus the CFM56-7BE-powered 737-800 NG (Next-Generation) aircraft on a 800 nm sector.
Importantly, Aspire Aviation continues to believe that the Boeing 737 MAX family aircraft has the fuel burn advantage with a short stage length of 500 nautical miles (nm) owing to the aircraft’s lighter airframe resulting in better climb profile and short-field performance, of which Boeing 737 chief programme engineer John Hamilton says the 737-900ER (extended range) is 10,000 lbs lighter than the A321, whereas the A320neo (new engine option) family aircraft has the fuel burn advantage with a longer stage length of 800 nm or above due to its better cruise performance.
Meanwhile, while the re-engined 737 MAX 9 is likely to have a slight fuel burn per seat disadvantage against the A321neo (new engine option) offering, which an AirInsight analysis puts at 2% while the 737 MAX 9 has a 4% better cash operating cost (COC) per trip at 4% less capacity than the A321neo, Boeing is very likely to introduce higher maximum take-off weight (MTOW) to enhance the aircraft’s payload/range capability to make it a closer 757 replacement aircraft, according to Aspire Aviation‘s sources at the Chicago-based airframer.
These sources say the structural reinforcements necessitated by the heavier and bigger CFM International CFM Leap-1B engine, mainly to the “localised strengthening” on the fuselage and the centre wing-box, coupled with the bigger CFM Leap-1B engine, contributed to a 800 kg (1,764 lbs) increase in the 737 MAX’s maximum empty weight (MEW). In comparison, the A320neo with a CFM Leap-1A engine weighs around 1,361 kg (3,000 lbs) more than the existing A320 aircraft.
The payload/range capability of the 737 MAX, these sources add, is likely to be improved by the partial fly-by-wire system on its spoilers which reduces the aircraft’s weight and redistributes loads inwards as well as a higher maximum take-off weight (MTOW) that will be larger than an 800 kg increase in the MEW, not taking into account potential weight-saving opportunities on the 737 MAX which the Chicago-based airframer is currently exploring.
“One of our requirements was that the MAX was going to need to fly essentially at least the same mission as the NG, so same range, same payload, if not better, and we are satisfied that the MAX will do that,” Southwest Airlines senior vice president (SVP) Brian Hirshman said.

"We're going to make some minor structural enhancements to the 737 Max, so we can have a slightly higher maximum takeoff weights so we can slightly increase the range of the airplane as well," said Tinseth at the Pacific Northwest Aerospace Alliance conference in suburban Seattle.

Tinseth declined to say what its target ranges or weights were for the Max family, but each variant would top its next generation 737 predecessor. The 737-700's design range is 6,200km (3,445nm), -800's is 5,700km (3,085nm) and -900ER's is 6,000km (3,235nm), respectively.

A higher maximum takeoff weight would allow the 737 Max to carry more fuel and payload, while offsetting the increased structural weight that comes with the larger 175cm (68.75in) Leap-1B engine fan.

Boeing has slowly detailed the changes it will make to the 737 Max to achieve a 12% improvement in fuel burn over today's Next Generation 737.

Tinseth's presentation identifies local strengthening of the empennage, fuselage, along with systems revisions, wing strengthening, a modified fuel system, longer nose landing gear and strengthened main landing as key changes to the 737 Max, along with the new pylon and nacelle needed for the larger Leap-1B engine.

Other changes include flight deck revisions and aft fuselage aerodynamic improvements.

Tinseth said there would be a 12% improvement in Leap-1B specific fuel consumption when combined with the 1% drag improvement on the aft fuselage, and paired with the 2% increase in drag and weight as a result of the structural modifications.

All told, Boeing claimed the re-engined 162-seat 737-8 will hold a 17% fuel burn advantage over today's 150-seat A320 and a five percentage point fuel burn advantage over the A320neo. Further, the 737 Max would have an 11 percentage points lower fuel burn than today's 737-800 on 1,100km (600nm) sectors, said Tinseth, who claimed today's narrowbody is 6% better than today's A320.

GE Aviation CEO David Joyce said 6 February the engine-maker, Boeing and Spirit AeroSystems had completed their engine installation studies, calling the configuration "nailed down".

The final configuration of the 737 Max will be frozen in 2013.