‘Less experienced pilots tend to fixate on automation and sometimes get caught up in the man-machine interface during abnormal situations in flight which can momentarily delay their responses to take timely corrective action’
LATE LAST week Boeing announced it had completed the fix for the 737 Max software. In a statement, Boeing said it had flown a Max on 207 flights for more than 360 flying hours. The software now must be reviewed by the US Federal Aviation Administration (FAA) and the regulatory bodies in other major jurisdictions in which the Max is likely to operate.
The worldwide grounding of the 737 Max in March after two fatal accidents within five months is estimated to be costing Boeing approximately $1 billion a month in loss revenues.
The 737 Max series aircraft was intended to be Boeing’s success story for the 21st century. On a cool December 8, 2015, the first 737 Max aircraft, dubbed “The Spirit of Renton,” was unveiled in the presence of thousands of employees. It was Boeing’s response to its major rival Airbus’s A320neo, with new fuel efficient engines and improved aerodynamics.
Since the grounding of the Max fleet, the US Department of Transportation has ordered an audit of the regulatory process that led to the FAA certification of the aircraft. The certification of the Max is the subject of probes by US congressional committees as it is felt the FAA may have been a victim of “regulatory capture.”
The major design difference between the Max and earlier variants of the 737 is the incorporation of a flight envelope protection called Maneuvering Characteristics Augmentation System (MCAS). The MCAS is intended to initiate automatic corrective action if the aircraft angle of attack sensors detect an impending stall down due a nose up attitude that can be caused at high thrust settings by the larger, higher and the more forward location of the Max’s LEAP engines, such as during takeoffs. Its purpose was to give pilots the “same feel” as the Boeing 737-800.
The fatal crashes of both Lion Air and Ethiopian Airlines Max aircraft are linked to the performance of the MCAS. Both accidents are under investigation and the final reports will identify the most probable cause(s) with several recommendations to prevent a reoccurrence.
Without prejudice to the ongoing investigations of both crashes, the experience of the pilots must be considered. The Ethiopian Airlines co-pilot had about 200 flying hours total experience and the captain was under 29 years old and his jet experience is not known.
Less experienced pilots tend to fixate on automation and sometimes get caught up in the man-machine interface during abnormal situations in flight which can momentarily delay their responses to take timely corrective action.
This could have been the situation with Ethiopian flight ET 302 as in the final moments, due to high thrust settings, the aircraft was travelling at speeds in excess of that required for that phase of flight, which could have made controllability difficult.
Aviation resides in a rapidly changing technological environment. The incorporation of the MCAS is part of the ongoing incremental automation in the design of aircraft and its systems aimed at reducing pilot workload with a consequent reduction in pilot fatigue, reduction in the size of cockpit crew and an overall improvement in operational safety and efficiency. Automation has significantly reduced aircraft accidents as evidenced by the latest Boeing accident statistics for all aircraft types.
Over the past three decades, the application of aircraft automation technology has provided important benefits in areas of fuel economy, flight controls, navigation and operations in all weather conditions. Automation has become a sales pitch for both Boeing and its competitor Airbus.
However, there should not be an overdependence on automation and aircraft designers must ensure that the pilots always remain in control and can override the automation if the need arises. This may not have happened in the Lion Air crash as preliminary data released on the crash seem to suggest that every time the pilots pulled up the nose of the aircraft, their actions were reversed by the MCAS automation.
Boeing’s competitor Airbus has had its fair share of automation problems during the first few years of the A320/321 operation. In June 1988 in Habsheim, France, a new Air France Airbus A320-111 operated by launch customer Air France crashed while making a low pass at the Habsheim Air Show. The pilots flew the aircraft slow at a low altitude because the purpose of the low and slow pass was to demonstrate that its computers would ensure that adequate lift would always be available regardless of how the pilots handled the controls.
The disputed causal factors were the slow response by the automated throttle control system to the captain’s input for increased engine thrust and the failure of the aircraft elevators to respond to pilot commands because the A320’s computers engaged its stall protection mode. Of the 136 people on board the aircraft, three perished.
Airbus was able to overcome its automation challenges by aircraft software upgrades and flight testing. Today, the A320neo is a major seller for Airbus with 612 delivered and 5,151 on order.
Likewise, Boeing and the FAA will eventually find acceptable solutions to the MCAS issues and the 737 Max will prevail and be around for a long time. Boeing has delivered 387 Max aircraft to date with a total of 5,012 on order.
However, the major challenge will be for foreign regulatory bodies to justify lifting the ban on the 737 Max which was debarred from operating in their respective jurisdictions. The big question for them will likely be whether the lifting of the ban will restore public confidence in the 737 Max.
Therein lies Boeing’s dilemma and this will require a massive and global public relations campaign by the company.
Ramesh Lutchmedial is a retired director general of Civil Aviation