Sunday, March 17, 2019

The Boeing story: A MAX problem that started with minimal upgrades

In the mid-2000s when oil prices began to rise, airlines started demanding for more fuel-efficient aircraft. In 2006, the two largest players in the sector – Boeing and Airbus – announced re-engined versions of their narrowbody workhorses that had been at the core of short-haul operations for carriers across the world. Both the Boeing 737 and the Airbus A320 had been immensely successful and the planemakers had opportunities in form of new engines in the market. Toulouse-based Airbus won the race and was able to launch the A320neo, or new engine option, equipped with either CFM LEAP 1A or Pratt & Whitney PW1100G powerplants.

Following its launch in December 2010, Airbus was able to sign deals for over 2,000 orders in the first two years. In July 2011, Airbus received a significant order of 130 A320neos and 130 A320ceos (current engine option) from the world’s largest airline American, which for the first time opted to purchase aircraft that was not Boeing-made. As per a New York Times report, American’s $38 billion aircraft purchase in 2011 also included order for 200 Boeing narrowbodies, half of which were to be equipped with a new and more fuel efficient engine, effectively indicating a commitment from Boeing to rehaul its 737 family instead of a completely new aircraft line. In August 2011, based on order commitments for 496 airplanes from five airlines, Boeing’s board of directors approved launch of a new engine variant of the 737.

In development, comparatively, both the A320neo and the 737 MAX were re-engineered versions of their predecessors, but it is pertinent to note that the A320 family that began in 1980s was a more modernised platform than the 737 family that was introduced back in 1960s. One of the main differences between the two was presence of a fly-by-wire control – an automated system of aircraft controls that allowed pilots to fly the aircraft using electronic signals transmitted via a wire, as opposed to manual controls using cables. The A320 was equipped with fly-by-wire controls, the 737 wasn’t.

During the development of the 737 MAX, Boeing, which had already introduced fly-by-wire on its 777 widebody model in 1995, decided to keep the electronic control system to a minimum on the newest narrowbody plane. Introduction of fly-by-wire on the 737 MAX would have meant a significantly higher development cost in financial as well as regulatory terms for Boeing.
Boeing did, for the first time, introduce fly-by-wire on the 737 in the MAX variant, but it was limited to spoilers of the aircraft and most other control systems were still devoid of the more modernised arrangement.

Even though fly-by-wire did not make the final cut in many of the 737 MAXs flight controls, a new and innovative system called MCAS was introduced in the airplane. MCAS, or maneuvering characteristics augmentation system, according to some reports, was put into the 737 MAX as a corrective measure for a problem discovered during one of the test flights of the jet. The new engine on the 737 – an optimised version of the CFM LEAP – was placed in a higher and more forward position on the aircraft wings. The placement of the larger engines caused the plane’s nose to pitch up in some conditions, and to prevent this, Boeing installed the MCAS, which automatically pushed the plane’s nose down when it was pointed up beyond a safe angle.
According to reports, following the Lion Air crash in October last year, certain pilot unions complained about the absence of MCAS in their flight crew operations manual and having never been trained about the new automated system. In India, too, it was only in December that the Directorate General of Civil Aviation (DGCA) introduced a fresh training course that took into account the MCAS. Further, given that the flight deck of the 737 MAX was similar to the 737 NG, India did not have simulators for the newer version of the airplane. Instead, DGCA mandated simulator operators to modify older 737 simulators to bring them “as close as possible” to 737 MAX systems.
17/03/19 Pranav Mukul/Indian Express

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