Human errors hide design flaw

Some of India’s flyers have just come past a frightening event aboard Jet Airways flight 9W 697. The 12-year-old Boeing 737-800 had taken off from Mumbai and was gaining altitude on its way to Jaipur. The cockpit crew or the cabin crew had forgotten to or failed to switch on the cabin pressurisation system. The drop in cabin pressure then led to enormous human discomfort and panic.

The human discomfort included severely constrained breathing and then bleeding through the nostrils. Such bleeding occurs when the body’s internal pressure exceeds the pressure in the cabin. Breathing in becomes difficult. Blood gushes out like gel from a toothpaste tube.

Words have gushed out too. The initial reaction has been to attribute the bloody and near-death event to human error. The widely read and the highly regarded Popular Mechanics has reported that the flight crew had forgotten to switch on the cabin pressurisation system. Popular Mechanics does not mention that the aircraft on this flight was a Boeing 737-800.

The report by Popular Mechanics separates the aircraft from the airline and its crew. It is human error. Other reports have done the same. It is human error. The common initial reaction after most accidents is to assign blame to drivers and pilots. The blame is couched and packaged in a soothing phrase: human error. The attribution to human error serves an important purpose: it rules out recklessness and sabotage.

However, the attribution to human error does not serve three important purposes: safety, comfort and speed. Humankind would not have travelled this far if every road, rail and air mishap had been attributed to human errors. We would still be driving Ford Model T. We would still be flying in aircraft designed by Orville Wright and Wilbur Wright.

We are not driving the Model T nor are we flying in aircraft designed by the Wright Brothers. We are indebted to designers. Design has evolved because of the imagination of system architects. Design has evolved because designers and system architects work together to serve passengers. The original equipment manufacturers and the carriers are merely bridges that connect their intellect with the customers. Modern equipment is on the roads, on the rails and in the air because of the intellect and the integrity of designers.

The designers and the system architects are human too. They should not commit the egregious error of sitting on their hands after a mishap. Operations could have human errors occasionally. However, every report on how human error had caused a travel mishap is an opportunity to push the evolution of design further.

There should be no human error in the evolution of design. There should be no human complacency. There should be no institutional indifference. The recent bleeding event in the skies above Mumbai points to complacency and indifference at Boeing.

The airline and its flight crew on 9W 697 have been the targets for disapproval and censure. That is unsurprising. Boeing enjoys a sound global reputation. By contrast, Jet Airways has a few business problems. It is easy in such circumstances to target the airline and its crew.

India’s aviation regulator, the Directorate General of Civil Aviation (DGCA), is investigating the event. The DGCA should expand the scope of its investigation beyond maintenance, engineering services in the apron, operations and crew training. It should ask a bold question: What has Boeing done in the last decade to fit its passenger aircraft with an intelligent system to maintain atmospheric pressure inside the aircraft cabin?    

A Boeing aircraft crashed with 121 passengers in August 2005 because of loss of cabin pressure. Helios Airways flight 522 crashed from an altitude of 10,400 metres near Grammatiko in Greece. The loss in cabin pressure deprived the crew and passengers of oxygen. It cruelly and fatally incapacitated the cockpit crew of the Boeing 737-31S. The Boeing 737-31S switched on to autopilot from manual pilot. The aircraft used all the fuel and then crashed. 

Boeing’s aircraft have an autopilot system. Boeing’s intelligent systems and flights control can together overcome the incapacitation of pilot(s). Automated sensing, and feedback and feed-forward controls can fly an aircraft when its human pilots are either resting or are incapacitated. These tasks are enormously complicated. The phrase ‘fly-by-wire’ is the result of the work by intelligent designers.

If pilot incapacitation can be managed using automated sensing and control, it is wholly possible to design systems that will overcome the forgetfulness of the cockpit crew. It is surprising that Boeing has not implemented an intelligent cabin pressure maintenance solution.

It has been 13 years since that tragic crash of Helios 522. A system that continually maintains normal air pressure inside the cabin at all times should have been designed by Boeing a long while ago. Sensors and control systems that measure pressure and then modulate it to stay at a specified level are used in several industrial systems.

Two leading design engineers associated with the United States Federal Aviation Administration (FAA) have said that switching on the cabin pressure system is too basic for pilots who undergo sophisticated training. Their stance: “One cannot design systems to overcome the basic failures and forgetfulness of highly paid, highly trained pilots.”

Use of the term “cannot” points to an inability. This undermines designers. There is no such thing known as an inability. Boeing’s designers would have delivered a pressure maintenance system if Boeing had seen itself as a firm that serves flyers. Boeing’s vendors would have built an intelligent and reliable cabin pressure maintenance system if Boeing had not been complacent after the Helios crash. Boeing’s complacency and indifference have hidden a major design flaw behind the screen known as human error.

The author is a financial and digital systems designer