Learning from the Boeing Max episode

We are all familiar with the Boeing 737 Max episode, the steps that followed the global grounding of Boeing’s latest, best-selling narrow body jet after two crashes that together claimed 346 lives. In October 2018, Indonesia's Lion Air Flight 610 had ended in the Java sea, while Ethiopian Airlines Flight 302 crashed into the Ethiopian countryside in March 2019. Both crashes took place while climbing, within a short span after takeoff.

It all started with Boeing’s desire to catch up with its competitor Airbus 320 Neo, which was enjoying a rush of orders and deliveries after upgrading to a new turbofan engine that was more efficient and ensured substantial fuel efficiency. Fierce rivalry between the two plane manufacturers forced Boeing to mount two latest fuel-efficient LEAP engines onto the 737’s iconic structure, a proven design since its maiden flight in the late 1960s. Unfortunately, Boeing’s design required greater ground clearance in its landing gear configuration whereas Airbus, a later entrant in the aerospace arena, had a significant advantage – its structural design had sufficient ground clearance already and could easily accommodate the new engine design size.

Boeing’s design engineers solved this issue by moving their new engines slightly forward from their original positions on the wings. This, however, brought in a new complication -- because the centre of gravity shifted, the 737 MAX began developing a tendency to push its nose upwards during the initial stages of the climb, when engine thrust is normally maximum, causing instability due to the altered design characteristic.

Boeing’s designers solved this problem by introducing the Manoeuvring Characteristic Augmentation System, or MCAS, a software system that received inputs from one of the two AoA ( Angle of Attack) sensors mounted on either side of the plane’s fuselage. These sensors gauge the angle of incoming stream of air relative to the wing position and signal the stabiliser mounted on the tail of the aircraft to push the nose downwards. The MCAS was designed to override manual inputs from the pilots. This design change worked well, except when a faulty vane causes the AoA sensors to give wrong information, leading to a stall.

Competition with Airbus 320 Neo forced Boeing to pretend that their 737 MAX behaved like their old version even when it did not. A press release from the US Department of Justice says that Boeing admitted in court documents that its airplane manuals and pilot-training materials lacked information about MCAS. Boeing perhaps felt this was too insignificant to include in the training manual, and not wanting to dent the new plane’s attractiveness did not compel airlines to invest in pilot training either.

Two tragic crashes later, after suffering billions of dollars in losses, Boeing introduced new wiring, new flight manuals, and prescribed new procedures for pilot training and new software so that signals from both sensors this time could send correct signals to the stabilisers to push the nose downwards even when one of the two AoA sensors erred.

India is concerned, too. We have one MAX operator, SpiceJet with 13 aircraft that will need the Directorate General of Civil Aviation’s nod to take off again.

What lessons should our Bengaluru headquartered aerospace and defence company HAL draw from the Boeing 737 MAX saga? HAL designs, develops or manufactures under licence military aircraft and helicopters, even a 19-seater Dornier commuter aircraft. Plans are afoot to build an Indian Regional Jet aircraft to cater to India’s estimated domestic demand of 2,000 narrow-bodied aircraft in the next 20 years. Fulfilling this requirement is bound to confront HAL in the future with what Boeing is going through today.

HAL designers must realise that all pilots flying its planes cannot be either test pilots or superheroes. There is no room for mistakes, so design engineers must be careful to design for the average pilot. Training should never be compromised. True, extra training costs extra money, but this does not allow aerospace companies to do away with simulators and training.

HAL should mandate adherence to Standard Operating Procedures (SOP) a key requirement of airline operations. Faced with a stall situation, despite the MCAS on the Boeing 737 Max not providing for a manual override, an SOP would have suggested to the pilots to operate two “Stab Trim” micro switches that directly control the stabilisers, preventing the plane from stalling.

The US Department of Justice was appalled with Boeing’s lack of candour while interacting with the Federal Aviation Administration’s Aircraft Evaluation Group, making misleading statements, half-truths and omissions regarding the MCAS, impairing their ability to ensure the safety of the flying public. When seeking approvals for its aircraft designs from India’s DGCA, HAL should not make similar mistakes.

Lastly, HAL, or any potential private plane-maker in the future, should never let corporate greed and profits undermine aviation safety. Human life has to be the No. 1 priority, and where safety is concerned, no compromise of any kind can be justified.

(The writer is a former Executive Director and Member, Board of Directors, BEML)