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Boeing planes: What's gone wrong?

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Boeing 737s have had serious problems of late (image by Bathara Sakti via Flickr).

Former pilot Norm Sanders weighs in on why there's been a spate of recent aeroplane tragedies.

THE BOEING 737 has been an icon in the airline industry for 50 years. Over 10,000 have been built and they are flying all over the world on some 500 airlines. They have carried over 12 billion passengers since they were first rolled out in 1968.

The Max 800 is the most recent update of the 737 which has had a number of facelifts over time. Boeing has invested its future in the new model. The company has already delivered 350 planes and until recently had 5,011 firm orders. Unfortunately for Boeing, the crashes have caused unease among potential customers.  Indonesian airline Garuda has planned to cancel its order for 49 aircrafts.

The Max 800 is an example of trying to squeeze a new aeroplane out of an old design. Boeing recognised the need for a fuel-efficient aircraft to compete with the Air Bus 320neo.

Boeing management decided it would be cheaper and quicker to further modify the 737 than to develop a new plane. Over the years, The Federal Aviation Administration (FAA) had allowed the aviation industry to police itself. The FAA granted Boeing wide latitude in the new design.

Questions are now being raised about the integrity of the U.S. aviation regulatory system itself. 

The bean counters prevailed over the engineers, the FAA sat back, and the old 737 airframe was modified to carry bigger engines. The original 737 had relatively small, pure jet engines which allowed the plane to have shorter landing gear to save weight and still have ground clearance.

These engines were relatively low powered and very noisy.

The 737 was re-engined with the now common turbofans. This caused a problem because there was no room under the wings for the bigger engines. The solution was to move the engines forward and flatten the bottom of the nacelles (the shrouds around the engine) for the required ground clearance.

The MAX 800 continued this trend. The larger, heavier engines were moved forward even further which changed flight characteristics but were 17% more fuel efficient. The bean counters were ecstatic.

The engineers, however, struggled to develop fixes for the instability problems which caused the nose to pitch up after takeoff. As a solution, Boeing developed software known as the Manoeuvring Characteristics Augmentation System, MCAS.

MCAS has a sensor that reads the plane's angle relative to the wind flow, prompting MCAS to automatically trigger the plane's nose to angle downward if it gets too steep. Too steep an angle leads to an “aerodynamic stall” where the wings lose lift.

Problems arise if the MCAS system gets erroneous sensor readings. The system immediately pushes the nose down, surprising pilots who are unfamiliar with the system and overriding their commands.

This is what investigators think happened to Lion Air Flight 610 before it crashed in October. It may have also played a role with Ethiopian Airlines Flight 302.

Aircraft are equipped with a control in the cockpit to “trim” the elevator to a desired position. Normal electric trim control by hand can stop the malfunctioning MCAS movement, but the MCAS will reactivate after five seconds after the switches are released if the angle is still sensed too high.

The roller-coaster flight paths of the two aircraft before crashing suggests the pilots were locked into this cycle. If they had deactivated the MCAS with the cutout switches and reverted to manual trim instead of fighting the computer, the accidents would not have happened. 

In fact, the same Lion Air plane that later crashed had narrowly averted an identical disaster the day before. A Lion Air Pilot travelling as a passenger in the cockpit jump seat recognised the MCAS problem from a briefing on the Max 800. 

He advised the pilots to switch the MCAS off and a crash was averted. Unfortunately, Lion Air allowed the plane to fly again the next day without fixing the malfunction and the pilots failed to turn off the MCAS.

U.S. pilots had reported the same MCAS difficulties for some time but had landed safely. This is a clue to the problem. The present crop of U.S. airline captains came up in the traditional method of aviation. They started at the local field in Cessnas or Pipers learning how to fly hands on.

No autopilots here!

They then graduated to charter work and maybe to a regional carrier. In Australia, they often got jobs flying in New Guinea where they honed their skills. Eventually, they joined the major airlines. If a piece of equipment malfunctions, they simply switch it off and fly by hand. To them, the autopilot is a very valuable tool, not an absolute necessity. 

The present fixation on technology was demonstrated in 2013 when the Korean airline Asiana Flight 214 smashed into a breakwater just short of the runway at San Francisco. The flight crew knew they were too low but were waiting for the throttles to automatically advance to give more power to the engines.

However, the autothrottles failed to operate and the Captain made no effort to move them forward by hand. The First Officer (co-pilot) failed to intervene and the Boeing 777 broke into three pieces when it hit the wall. Miraculously, all the passengers and crew survived the crash but a woman was later killed when she was run over by a fire truck.

Pilot training will be a major component of dealing with the Max 800 problem. 

A very experienced U.S. airline Pilot and instructor suggested a temporary fix:

“Require a week in the simulator — for overkill to make sure it penetrates even the dimmest bulbs. But nobody flies again until they have it. In effect that grounds the fleet, but only so long as the training takes.”

He pointed out that learning how to move two switches to turn off a runaway MCAS was much easier than practising how to deal with an engine fire or total hydraulic loss.

The reasons that the next generation of pilots are less skilled in dealing with unusual situations are numerous. For one thing, fewer and fewer aspiring airline pilots have much experience in aviation problem solving in general and in flying manually in particular.

Sully Sullenberger succeeded with his landing in the Hudson River due to his extensive flying experience. This included his time spent as a glider instructor at the U.S. Air Force Academy before he became a fighter Pilot (The Air Force Academy first starts flying training in gliders to develop hands-on flying skills).

Qantas Flight QF 32 had an engine disintegrate just after taking off from Singapore for London. Hydraulic lines and controls were cut and the aircraft was severely damaged. Captain Richard Champion de Crespigny, the Pilot, landed the crippled A380 successfully. “We had to fly it by hand like a Cessna,” he said later.

Modern pilots are increasingly graduates of “academies” and receive as little as 80 hours of instruction in actual flying (For comparison, New South Wales requires 120 hours of instruction for a vehicle driving license). 

The trainees are subsequently put in simulators for a few months and then into the right-hand seat of an airliner.

The First Officer of Ethiopian Flight 302, a recent academy graduate, had only 200 hours of total flight time! 

In the U.S., the FAA requires 1,500 hours and additional training for a similar position as does Jet Star in Australia. 

Unfortunately, training costs money and profit takes precedence.

Crashes caused by “pilot error” can often be explained by the culture of the nationalities involved. Societies that are very class-conscious lead to the first officers deferring to the captain even when the situation is deteriorating to disaster.

Korean Airlines had many fatal crashes between 1970 and 1999, during which time it wrote off 16 aircraft in serious incidents and accidents with the loss of 700 lives. The last fatal accident led to a review of how Korean cultural attitudes of deference to authority had contributed to its poor crash history. For several years, Western pilots were included on the flight deck to intervene in critical situations.

Generation Z kids (born around 2000, more or less) are increasingly living in a virtual reality world on their screens. This is the group which will furnish the 790,000 new airline pilots that will be needed worldwide over the next 20 years. 

Will they be able to cope when the screens go berserk and the red warning lights start to flash on the instrument panel?

The Max 800 will be back in the air soon after software and sensor updates (It would have been sooner but for the Trump government shutdown which affected the FAA).

It will be much harder to fix the problems caused by cost-cutting airlines whose pilots have limited basic flying knowledge, lack situational awareness and are incapable of thinking outside the box in an emergency.

Dr Norm Sanders is a former commercial pilot, flight Instructor, university professor, Tasmanian State MP and Federal Senator.

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