The Boeing 737-Max’s maximum-size problem

When Boeing developed their latest-generation B737MAX, to keep their half-century old best-selling single-aisle airliner contemporary, they introduced new technology that was not available on earlier variants, in order to further enhance its air safety. It was called the Manoeuvring Characteristics Augmentation System (MCAS) – software for the automated flight control system. It was designed to make the controls of the B737 MAX feel like those of the earlier-generation B737 NG (New generation) It also had another purpose.   Should the aircraft’s forward speed fall below its stall speed – the speed below which it would no longer be able to sustain controlled flight, and would crash – the MCAS would automatically push down the tailplane (the horizontal stabilizer in technical parlance). That, in turn, would give the aircraft a nose-down attitude, and help it to recover speed well beyond the stall speed.

That sounded great, at least in theory. However, it did not take into account the glitches and gremlins that can come to haunt such new advanced-technology developments. Then, things began to go wrong.  A number of Boeing 737MAX pilots reported that their aircraft developed a nose pitch-down problem for no apparent reason. The pilots struggled with their controls to bring their aircraft back to normal, straight-and-level flight. During those see-saw battles, the aircraft alternated between nose-up and nose-down attitudes and sharp changes of altitude as the aircraft alternately climbed and descended. It must have been a traumatic experience for the pilots – and even more so for their passengers. Some pilots are said to have solved that problem by switching off the autopilot. However, for long-range flights, an aircraft always “flies itself” – on autopilot. For a pilot to take over full hands-on control, probably for hours, may not have been a good option.  In any case, it was the lesser evil.

A number of Boeing 737MAX pilots reported that their aircraft developed a nose pitch-down problem for no apparent reason. The pilots struggled with their controls to bring their aircraft back to normal, straight-and-level flight. During those see-saw battles, the aircraft alternated between nose-up and nose-down attitudes and sharp changes of altitude as the aircraft alternately climbed and descended. It must have been a traumatic experience for the pilots – and even more so for their passengers.

Sadly, during all that time, Boeing did not give B737MAX pilots any additional training to be able to handle that aircraft and did not publish any bulletins on how to deal with such emergency situations.  Neither did the pilots’ flight manual brief them on what they could expect when flying the B737MAX. In short, there was a tragic failure of adequate communication.

Boeing did finally issue a bulletin on 6 November 2018, on what pilots should do in case such a situation develops. Sadly, that was only after the crash of Lion Air Flight JT-610 in Indonesia on 29 October 2018. with the loss of 189 lives. There were no survivors.

However, their belated action did not prevent the crash,about five months later, on 10 March 2019 of Ethiopian Airlines Flight ET 329 with the loss of another 157 lives. Again, there were no survivors. It would be worth finding out why that second crash occurred after Boeing had issued their bulletin.

Importantly, Ethiopian is no banana-republic airline. It is the pride of Africa and has an enviable safety record. The ill-fated flight had been commanded by a very experienced Commander. Those two crashes within five months have together killed about 350 people.

In the investigations that followed, the contents of the crashed aircraft’s Flight Data Recorders and Cockpit Voice Recorders were carefully studied and analysed. The needle of suspicion unambiguously pointed to the MCAS. Earlier, a satellite-based system that had tracked these flights had also revealed sharp changes in aircraft pitch angles. (The angle that an aircraft wing makes to the free-flow air is called the “angle of attack”) These changes in pitch had led to sharp fluctuations in altitude.

These investigations confirmed that the two aircraft had crashed for the very same reason – the rogue MCAS which had received wrong data inputs from the angle of attack sensor. Both aircraft had been very new, had developed the problem within minutes after take-off, had the same type of altitude fluctuations, and neither aircraft had any survivors.

The highly respected US Federal Aviation Administration (FAA) had been about the very last agency in the world to ground the B737MAX – after two crashes had snuffed out almost 350 lives. It is now revealed that the FAA had an undesirably cosy relationship with Boeing, and had allowed Boeing considerable leeway in the safety clearance of their own aircraft. The US Transportation Department’s decision to launch a probe in to this could lead to more shocks regarding this very sorry episode.

There is another worrisome point that needs to be covered. Ethiopian Airlines claim that they had flown their B737MAX aircraft for well over a thousand hours after the start of services without experiencing any such problems.  Why did the MCAS problem suddenly erupt on Ethiopian Airlines’ Flight EJ 302 on 10 March last? This is most worrisome.

That is not the end of this sad story either. The highly respected US Federal Aviation Administration (FAA) had been about the very last agency in the world to ground the B737MAX – after two crashes had snuffed out almost 350 lives. It is now revealed that the FAA had an undesirably cosy relationship with Boeing, and had allowed Boeing considerable leeway in the safety clearance of their own aircraft. The US Transportation Department’s decision to launch a probe in to this could lead to more shocks regarding this very sorry episode.

Fortunately for Boeing, only about 400 B737MAX aircraft have been produced to-date. And most airline customers have received only a few of this aircraft type so far. While some airlines may even cancel their orders for this aircraft, their numbers are likely to be small. The compensation to Lion Air and Ethiopian Airlines, and to the relatives of those who died, may not exceed dollars one or two billion.

However, these may be the least of Boeing’s problems.  Boeing continues with full production of that aircraft, at over 50 aircraft a month, as a stoppage of production would cause an unmanageable disruption. However, they have had to suspend deliveries of the aircraft as no airline will accept them till Boeing satisfactorily rectifies the flaws. Thus, Boeing will not receive payments till the completed aircraft are delivered to – and accepted by – their customers. However, they have to spend very heavily to produce these aircraft, for which the total order book stands at about 4,700 aircraft. This outflow of funds on the one hand, without any comparable inflow on the other, may not be sustainable for long. Thus, much depends on how rapidly Boeing can develop the software “fix”. Boeing claim they can do it in a matter of weeks. Some analysts expect it to take as much as three years to bring this crisis to a satisfactory end. That could hit even a cash-rich juggernaut like Boeing very hard. This turn of events will tarnish Boeing’s image.

(The writer is a noted aerospace industry analyst and author of “Civil Aviation in India: Challenges and Prospects”)