Glass vs. Steam

By the mid-1970s, commercial aircraft cockpits were crammed with over a hundred instruments, gauges, and controls vying for the pilot’s attention. NASA, which kept reaching further and more frequently into space, faced the cockpit flight-management-system problem on a much larger scale. NASA turned to emerging computer technology to sort system- and flight-data into a user-friendly format displayable on a cockpit monitor, creating the first glass cockpit.

Commercial aircraft soon followed NASA’s lead. Economies of scale prevented general aviation aircraft from joining the bandwagon in earnest until the early 2000s, but now most new aircraft feature glass cockpits. It could be just a matter of time before the steam gauge is a thing of the past.

So it stands to reason that with all of this investment in streamlined flight management, when it comes to life in the sky, glass must be safer than steam. Or is it?

AOPA’s Air Safety Institute (ASI) released a study (1) in March that tracked over 20,000 single-piston aircraft built from 1996 to 2010which agrees with a similar two-year NTSB study (2) of 8,364 single-piston aircraft built from 2002 to 2006. Each study compared accident rates for aircraft with steam gauges versus those with glass cockpits: NTSB reviewed GA accidents from 2002 to 2008; ASI looked at GA accidents from 2001 to 2010. Both studies concluded that airplanes with glass cockpits are no safer than analog (steam) cockpits.

I fly both glass and steam, VFR and IFR, and it is much easier for me to assimilate information and manage the flight when I’m flying with a G1000 panel. I don’t know that they have found the right metrics to assess what a glass cockpit with a moving map display, XM weather, and traffic information does to help a pilot’s situational awareness. On the other hand, I know that pilots can be mesmerized by the glass displays to the point they forget there’s a world outside the cockpit.

The ASI study (over 20,000 piston powered aircraft manufactured between 1996 and 2010) found that :

“The most dramatic differences in the accident record were between three distinct groups of aircraft:

·   Single-engine fixed-gear models producing less than 200 horsepower had the highest accident rates but the lowest rates of fatal accidents.

·   Complex and/or high-performance models certified prior to 1980 had less than half as many accidents relative to time in service, but their fatal accident rates were no lower.

·   The accident rate for models certified since 1998 with engines of 200 horsepower or more was more than 20% higher than in the most comparable legacy models, and their fatal accident rate was more than 60% higher.

However, within each of those categories, differences between analog and glass panels were minimal.”

What these studies tell me is that aircraft equipment is not the major factor in general aviation accidents. The real problem is, and has been, what my mechanic friends call the throttle-yoke interconnect—the pilot.

Risk management and the ensuing decisions pilots make before or during a flight get them into trouble more often than mechanical issues or what kind of equipment they have in the cockpit. The statistics over the last twenty years tell us that operator-errors account for almost 80% of aircraft accidents. If you read the details, you’ll find more often an accident resulted from poor risk analysis or a bad decision—despite the awareness of the identified risks—and not the lack of flying skills.

All of us know of accidents where, after the fact, it’s easy to criticize the decision the pilot made. Hindsight is 20/20, so try to put yourself in the pilot’s frame of mind at the time. There are two reasons pilots make bad choices when they are in the middle of the event looking forward. The first is that most of us are goal oriented and we want to accomplish what we have set out to do. It’s difficult to overcome that inertia when things start going badly. That’s self-imposed internal pressure to complete the flight. The second reason we make poor decisions is external pressure:  We make commitments to others and we don’t want to let them down, such as someone traveling with us or someone at our destination who expects us to arrive for a business or family activity. In any case, it takes a very strong and disciplined pilot to change the plan or even cancel the flight. I know I’ve made decisions that seemed reasonable at the time but didn’t look so brilliant after the flight.

None of us go flying with the intent to get into trouble or have an accident. In fact, we wouldn’t be doing what we are doing if we didn’t think it was safe.

The bottom line is that we get ourselves into trouble by not fully appreciating or respecting the risks we identify. It’s an individual responsibility to make the right choice, but the better we analyze the risks, the more obvious the best solution will be.

1. http://www.aopa.org/training/articles/2012/120301report-compares-glass-analog-panel-safety.html and http://www.aopa.org/asf/publications/topics/TAA-Report-022412.pdf

2. http://www.ntsb.gov/doclib/reports/2010/SS1001.pdf

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About Rich Martindell

Instrument flight instructor (CFII), rated airline transport pilot (ATP), former military instructor pilot in F-4s and F-15s. Aircraft accident investigator and flight safety consultant. FAA Safety Team Lead Representative.
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