Human Factors

According to Dismukes and his researchers in a presentation, The Hidden Complexity of Cockpit Operations, conventional wisdom tells us pilots become accustomed to concurrent task demands, interruptions, distractions and disruptions while the truth is pilots routinely manage multiple, competing, concurrent task demands just fine. At least until theres an interruption. The presentation lists four situations when pilots are vulnerable to omissions when performing routine tasks:

Pilots routinely make strategic plans for their flights. By expanding that idea a little to imagine some what ifs at various points along the planned flight-weather deterioration, passenger problem, airplane or system malfunction, or other potential hazard-and then decide on alternative plans for each major stage of the flight, the risk of plan-continuation bias and the negative effects of snowballing workload and stress are reduced.

The term multitasking originated in the computer industry and refers to a machines ability for perform more than one task simultaneously. Even though modern operating systems with which were all aware provide the illusion of multitasking, true implementation on a computer requires a multiple-core processor. The same could be said for humans.

Ive noticed there is a bias, sometimes spoken aloud, that a pilot who made some sort of a mistake and had an accident was either not terribly bright, lacked basic skills or just plain didnt have the magical right stuff. As an instrument instructor, Ive certainly seen pilots with poor skills or who werent terribly bright or had lousy judgment, and some of them crashed an airplane. Ive also seen some extraordinarily good pilots who were possessed of all the right stuff imaginable, who also made mistakes and crashed.

So, youve decided the risk is worth it and youre going to execute a zero-zero or low-visibility takeoff. Youve thoroughly prepped the airplane, the cockpit and yourself for the operation, youve practiced it, you have a solid-gold takeoff alternate only a few miles away, with an ILS above minimums, and youre ready. One problem: The weather is so bad, you cant see more than one or two of the runway stripes at a time. Is that enough to help ensure directional control on the takeoff roll? Probably not.

It had been a long day: Several hours breathing O2 in the low teens, covering more than 1000 nm. But I was on the ground, safe and sound, at Cheap Gas Muni. I was all topped off and on the takeoff roll for the short hop to Cheap Hangar Field. I had to do some broken-field running to get here late on this summer afternoon, but thanks to Nexrad and ATC, I was able to avoid the big bumps and hadnt even gotten wet.

In response to your October editorial, Hot Water, what I took from these two tragic accidents was that the culture of fear surrounding declaring an emergency is killing people. The FAA needs to change its policy calling for an emergency declaration investigation to address this fear.

In last months Editors Log, under the heading, “Unwritten Rules,” we discussed the tragic August 8, 2009, mid-air collision between a Piper PA-32R-300 and Eurocopter AS350 operating as a for-hire tour over the Hudson River off New York City. The Piper had just departed nearby Teterboro Airport while the helicopter had launched a few moments before from the West 30th Street Heliport. The two collided over the Hudson Rivers west bank; all nine aboard both aircraft perished. The collision engendered just the kind of hysteria to which those who pay attention to the mass medias coverage of general aviation have grown accustomed. Elected officials and average citizens alike marched forth to complain there were no rules concerning such operations, and non-scheduled flights should be (choose one or all) banned, subject to specific training and approvals or under new operating rules, including positive ATC direction.

As we noted in our January 2007 article, “Because it involved two very modern jets operating under IFR and equipped with the latest in collision avoidance equipment, and because it occurred in controlled airspace, this is an accident that simply should not have happened.” We could have added to that statement information regarding Brazils modern ATC system, along with a discussion of the hyper-accurate altimetry and navigation systems required in RVSM (reduced vertical separation minima) airspace implemented throughout the world between 1997 and 2005. In fact, its arguable the accident happened because of RVSM and the accuracy it demands. Think about it: In years past something called the “Big Sky Theory” applied to so much of the altimetry and navigation standards. That theory held that, even if ATC screwed up and violated separation standards or-as in this case-put two oncoming aircraft at the same altitude-the inevitable variables in tracking a VOR radial or selecting barometric pressure in a Kollsman window provided a margin of error against midair collisions. Instead, this midair collision occurred in spite of all the “slack” built into the system. As the computer-generated image on the facing page demonstrates, the two aircraft were pretty much at the same altitude and displaced only 60 or so feet laterally. In the scheme of things, those are “noise-level” errors, the values of which dont really matter. In years past, with less-accurate systems, you couldnt have put these two aircraft that close together if you tried. The other automation-related event helping ensure this tragedy involves the way Brazils ATC system computer inserts a flights “cleared” altitude into the datablock displayed on controllers screens. In the event, they were presented with ambiguous data showing what the NTSB described as both the Embraers requested and cleared altitude. As the NSTB summarized it, “a design in which two distinctly different pieces of information…appear identical on the display is clearly a latent error.” Brazilian authorities defended this data presentation by noting, “controllers have always operated the system in this manner,” according to the NTSB. The NTSB went on to note the original clearance received by the Embraer crew cleared them to maintain FL370. Upon reaching the Brasilia VOR (BRS), the flight turned northwest to follow airway UZ6. As the NTSB drily put it, “The automatic change to the cleared altitude field did not accurately reflect the status of [the Embraers] clearance.” See below for an excerpt of the relevant FAA/NACO en route chart.

In this series first installment (“The Problem With Flight Training,” March 2008), we identified a few of the systemic errors and omissions committed during flight training, and how they feed into typical aviation accidents. We dealt primarily with issues pertaining to the mechanics of flying an airplane. In this second of three articles, well look at some of the psychological aspects involved. A lot of educational material has been generated in recent years on aeronautical decision making, hazardous attitudes and cockpit resource management. The FAA has been actively promoting the Perceive-Process-Perform (P-P-P) risk management decision path as well. Perceiving risk in the P-P-P model is aided with the PAVE checklist; processing levels of risk is facilitated with the CARE checklist; and performing risk management is prompted by the TEAM checklist (see the sidebar on page 6 for more).