NMA focus needs to be on engines

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March 19, 2018, © Leeham Co.: As the market awaits a decision by Boeing whether to launch the New Midrange Aircraft (NMA, or 797), focus has been on the aircraft’s definition and market demand.

It should be on the engines.

It doesn’t matter whether Boeing designs a fabulous airplane that’s the next best thing to sliced bread. What matters is whether the engines will be ready in time for Boeing’s suggested entry-into-service and if they are, whether they will be reliable out of the box.

The recent track record isn’t all that encouraging. Neither is Boeing’s preferred timing.

  • CFM, GE, Pratt & Whitney and Rolls-Royce each had problems with their new engines. All continue.
  • The Boeing NMA requires brand new engines, not derivatives.
  • Engine development and certification within the Boeing preferred timeline is sporty at best.


Boeing continues to maintain publicly that entry into service is targeted for 2024 or 2025. CEO Dennis Muilenburg recently said program launch could come within “a year or so.

Indeed, one scenario calls for Authority to Offer by the end of this year and formal program launch early next year.

However, LNC has been told by persons in the supply chain and airlines that Boeing also has said EIS could be targeted for 2027. (Boeing called these reports “inaccurate.”)

Timing all comes down to the engines and when they will be available. LNC has been told a 2024-25 EIS is a timeline that is unlikely to be met by the engine makers; another year at least would be needed, making EIS 2025-26. Those telling LNC 2027, as recently as last week, is the target specifically cite Boeing saying this is due to engine readiness.

New Engines

Although CFM and Pratt & Whitney would rely on their existing LEAP and GTF technologies, the NMA would have entirely new engines.

GE’s CEO David Joyce said at the Singapore Air Show CFM’s engine won’t be a geared turbo fan. GE owns 50% of CFM.

Rolls-Royce is developing a new engine, with a core available by 2020.

A new engine must be certified one year ahead of flight testing, which itself must begin at least a year ahead of EIS. The latter backs up the timeline from a 2024-25 EIS to 2023-24 and the former to 2022-23.

Engine certification, therefore, falls within three or four years from program launch if in 2019—a timeline that cannot be met, LNC is told.

Track record

The track record of engine development is hardly encouraging.

Pratt & Whitney’s in-service issues of the GTF on the A320neo are well documented, with the most recent issue the grounding by the Indian aviation authority of GTF-powered A320neos at Indigo and Go airlines. (Europe’s EASA and the USA’s FAA didn’t determine the need to ground the GTF airplanes in their jurisdictions.)

Less serious problems exist on the Bombardier CSeries, which use a different version of the GTF. The CSeries has been in service for about a year. Embraer’s E190-E2 enters service next month. It uses the same engine as the CSeries.

Mitsubishi’s MRJ90 flight test program was interrupted by an in-flight GTF engine shut down. Mitsubishi suspended flight testing for a short time while the cause was determined.

CFM’s LEAP 1A and 1B are not without issues. The LEAP 1A powers the A320neo. Technical issues, while not as severe or prolonged as the rival GTF, caused Airbus to suspend delivery of engines for a short time. Over at Boeing, photographers documented many 737 MAXes on the Renton Airport flight line without engines as CFM fell being in production and delivery.

Rolls-Royce is still struggling with engine reliability issues for the Trent 1000 that powers the 787. The basic Trent 1000 entered service in late 2011. More than seven years later, airlines were hit with faulty fan blade. Several carriers, notably Air New Zealand, ANA and Virgin Atlantic, saw service disruptions as several aircraft were grounded for extended periods while awaiting repairs or replacements to the engines. ANZ is only now putting its grounded aircraft back into service. Virgin Atlantic is leasing in Airbus A330-200s and returned to service an Airbus A340-600 to make up for its grounded aircraft.

Rolls’ issues with the engines delayed development of the Airbus A330neo, which uses the Trent 7000—essentially the Trent 1000 TEN with bleed air. The A330neo program is nearly a year behind schedule.

GE Aviation isn’t left out. Its GEnx engine, also for the 787, entered service in early 2012. It’s also one the Boeing 747-8 in a bleed air version. Icing issues emerged for both engines. More than five years later, icing remains a problem.

The bottom line

The bottom line is that with a poor track record for engine development, Boeing’s desire to push the timeline for a brand new engine for NMA to meet a 2024-25 EIS appears to be a very risky bet.

This is why a 2027 EIS is being discussed by some. It’s why LNC remains skeptical of Boeing’s public position.

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