Glass cockpits: technology and aviation applications

Human interaction with Glass Cockpit & computerized flight systems

Human interaction with computerized flight systems is viewed by many as the "Achilles heel" in modern commercial flight. While pilots as the ultimate end-users must bear the responsibility for the systems under their control, it is the designers who must shoulder the burden for taking into account the human factors likely to cause confusion. How information is displayed has a tremendous impact on how it is interpreted. Indeed, graphical displays and glass cockpits are here to stay -- but so too are human pilots."(Krell)

The purpose of this paper is to explore an emerging technology known as the glass cockpit and to seek to explain the human factors that influence the implementation of this technology. This discourse will describe the theoretical issues of the glass cockpit technology and the human factors associated with the invention and subsequent implementation of the technology. We will also focus on the advantages and disadvantages of the technology. We will investigate the development of the technology and compare the glass cockpit technology with the traditional cockpit. We will also discuss the military and civilian uses of the technology. Finally we will explore the future trends of the glass cockpit.

Description of Glass Cockpit Technology

The term "Glass Cockpit" describes a cockpit in which all of the displays are painted onto the glass of a computer screen. Glass cockpits replace a number of, switches, gauges, and indicators with automated display systems. The use of computers to manage the on-board systems, allows pilots to describe what they want to observe at the exact time that they want to observe the indicator. Glass cockpits have allowed contemporary aircraft to require only two crewmembers as an alternative to the three needed by traditional cockpits. (Krell)

According to NASA the technology began to appear first in the 1970's when flight-worthy cathode ray tube (CRT) screens began to substitute some of the electromechanical instruments displays, and gauges. These new "glass" instruments, gave the cockpit a different look and so the name, "glass cockpit" was adopted. (NASA Facts Online) NASA facts' online writes, "Prior to the 1970s, air transport operations were not considered sufficiently demanding to require advanced equipment like electronic flight displays." (NASA Facts Online)

Ultimately the escalating intricacy of transportation aircraft, the arrival of digital systems and the increase of air traffic congestion near airports began to increase the demand for such equipment. (NASA Facts Online) This was because most transport aircraft in the 1970s had more than 100 cockpit instruments and controls, and the main flight instruments were crammed full with indicators, crossbars, and symbols.

The increased amount of cockpit instruments were consuming the attention of pilots and taking up space. It became evident that crews would benefit from displays that could route the unprocessed aircraft system and air travel data into an incorporated, simple depiction of the aircraft location, position and movement, in horizontal and vertical dimensions, and also with regard to time and speed, as well. (NASA Facts Online)

In response to the growing need for a new cockpit design NASA began to research effective ways to reduce clutter and aid pilots. Engineers at NASA Langley Research Center in Hampton, Virginia worked with industry partners to create and test electronic flight display concepts. Industry partners included Boeing and Rockwell Collins. Boeing contributed by allowing some of its' engineers to participate in the venture. Rockwell Collins created hardware turned the team's concepts into hardware. These test were concluded by a series of flights to demonstrate a full glass cockpit system. (NASA Facts Online)

The designing of the system caused the researchers to examine the information that crews would need and how the information could be presented to them in an effective manner. A primary challenge that researchers discovered was, judging the accurate balance involving what the computerized system ought to control and what the pilot ought to control. (NASA Facts Online)

As a result of the experiment a glass cockpit system with an autopilot that increased safety by decreasing pilot workload at peak times. The new system also allowed pilots to maintain situational awareness. Realistic terminal area flights with the NASA Boeing 737 flying laboratory created a great deal of interest among commercial airline pilots and others in the aviation industry. This interest allowed the technology to be certified by the Federal Aviation Administration. The success of the project was made evident when the Boeing 767 was introduced in 1982.

NASA Facts Online)

Human Factors

Human factors play a large role in the design and implementation of any new technology. The following paragraphs will discuss the human factors involved in the development and subsequent implementation of this technology. In addition this section will also discuss the human factors that have led to accidents in aircraft with glass cockpit technology.

The graphical display of a glass cockpit plays a crucial role in conveying to the flight crew. If this data is misread, misinterpreted, or misunderstood, the consequences can be catastrophic. Understanding this human factor allowed the developers of this technology to be sensitive to how human beings interpret data presented on a computer screen. (Krell)

NASA noted that one of the most significant factors display designers keep in mind is that an abundant supply of color availability should not influence the use of unnecessary colors. Dr. Jeffrey McCandless, a human factors engineer at NASA's Ames Research Center in Mountain View, CA explains, "We make colors as distinct from one another as possible...Enough to distinguish from each other, but not too many to confuse the astronaut." (The Glass Cockpit)

Another human factor that was taken into consideration was the connotations that certain colors represent. For instance, red is used for warnings and yellow for caution. In addition contrast is an important factor, such as white text on a black background or black on white, to reduce the chance for pilot error. Flight Deck Controllers don't want pilots to miss vital information even if no emergency exist Researchers found that a way to accomplish this is by highlighting the important information on the display so it is more prominent this is done by making the text larger and bolder. (The Glass Cockpit)

Another factor involved in the glass cockpit technology is "automation complacency." Automation Complacency creates human error that is related to automation. This human factor involves the over reliance on automation which draws the pilot away from flying the airplane. In this instance the pilot's role becomes more of an observer than an actual participant, and it takes a longer time to recognize what's happening if something out of the ordinary occurs during a flight. (Steinberg)

In the 1996 the Human Factors Team of the Federal Aviation Administration conducted a study, which examined human factors involved in aircraft accidents where the aircraft utilized glass cockpit technology.

The following paragraphs are paraphrased excerpts from the FAA study.

CRM was found to be the most commonly occurring human factor in all incidents involving glass cockpit aircraft. The study found CRM to be linked with incorrect settings, monitoring and vigilance, inadequate knowledge of aircraft systems, experience and flight handling. Distractions were found to be contributory in 21% of accidents; workload played a part in 14% of reports, while situational awareness was found only in 7% of reports. When Situational Awareness was a factor, further analysis found it was linked to incorrect setting. (Incident and Accident Review)

The behavioral factors, including flight crew perception and complacency were not found to be the most significant common factors in aircraft accidents. The study found that complacency was found in 13% of reports and was more often a non-primary cause than a primary one. Complacency is not an easy factor to identify in incident reports, this is because it is a sub-factor of CRM related to poor flight crew communication and monitoring behavior. Flight crew perception occurred in 5% of all reports was more equally used as a primary or non-primary cause of accidents and incidents. (Incident and Accident Review)

General automation issues also had dramatic findings. The study found that incorrect settings accounted for 28% of all reports and in three quarters of these it was a principal factor. Incorrect settings can be linked to derisory interface design, poor perception of the system and legitimate error. In terms of the incident/accident reports, general automation issues were found to be strongly related to monitoring and vigilance where an unobserved flawed input caused very serious problem later on in the flight. In addition the FAA found that the improper use of systems occurred in 15% of the reports and resulted from poor understanding of the technology and not using procedures properly. (Incident and Accident Review)

The final human factor that the study found was Lack of mode awareness. Which was recognized as a factor in 6% of reports and was connected to experience and inadequate knowledge of the aircraft system in addition to monitoring/vigilance and incorrect setting items. This factor did not occur as often as researcher might have expected because it is difficult to report what one is not sentient of, when recounting a situation for an accident or incident report. (Incident and Accident Review)

Pros and Cons

As with any technology there are benefits and risk associated with the implementation and usage of the technology, the glass cockpit is no exception to this rule. As we have discussed there are several benefits associated with the glass cockpit. The cockpit is much more cost efficient than traditional models because they requires less to maintain the system. The displays of the also make it easier for crews to read crucial flight indicators such as altitude and speed.

The disadvantages that the technology presents are primarily caused by human factors. These factors include the complex system of displays, overconfidence in the technology of the system, poor training and automation complacency. In short many pilots that operate such systems are becoming increasingly more dependent upon the technology instead of their training as a pilot.

In addition to the human factors associated with the system there are also some design flaws. The glass cockpit design flaws have impeded air accident investigations because unlike traditional cockpits, the modern glass cockpits have no displays for memory. Thus the glass cockpit provides investigators with little information as to why an accident has occurred. This poor design has critically decreased the volume of information available for accident analysis. (Future Video Aircraft Recorder)

Comparison of Glass Cockpits and Traditional Cock Pits

The glass cockpit features nine AMLCDs on the forward flight deck and two on the aft flight deck that replace 32 conventional gauges. Each display is 6.7 square inches. In addition to providing the pilots with color screens, the displays weigh less and consume less electricity than the traditional old green cockpit screens and the conventional displays. Glass Cockpits use computers based on Intel control the glass cockpit displays® 80386 chips and they are well equipped to provide the automation that is needed. (The Glass Cockpit)

Airlines and their passengers, alike, have benefitted from the advent of glass cockpits. NASA reports, "Safety and efficiency of flight have been increased with improved pilot understanding of the airplane's situation relative to its environment. The cost of air travel is less than it would be with the old technology and more flights arrive on time. " (NASA Facts Online)

Military and Civilian Uses

The military uses glass cockpits to train pilots and the cockpits are used in military aircraft such as the F-117 stealth fighter. Glass cockpit technology is also used on civilian aircraft such as the Boeing 777. The glass cockpit technology has proved to be beneficial in both cases.

For the military the introduction of glass cockpits, off-bore sight air-to-air missiles, precision guided air-to-ground weapons and helmet-mounted sights will transform the manner in which pilots are trained and manufacturers are actively developing the next generation of trainers to meet these requirements. In addition the Air Forces that find some technologies to be expensive see the armed trainer as a method of acquiring a limited combat capability at a price they can afford. (New Trainers Prepare For Takeoff)

The Military also uses flight simulators that feature realistic aerodynamic models, functional glass cockpits and avionic panels, and stick and throttle controls to train pilots. Several aircraft are connected in the same virtual world, which each pilot can see from their own perspective projected on eleven foot by ten-foot screens. The simulators allows pilots to operate from land bases or take off and land from aircraft carriers to fly in daylight or darkness and in unpredictable weather conditions. The pilots are guided by an air traffic controller who helps instruct them to fly and guides them through their preplanned mission. These preplanned missions include military operations and general flight training practice as well as combat against real or artificial enemies. (Fighter Town User Survey)

The glass cockpit technology is also used on many commercial aircraft. The acceptance of this technology on commercial aircraft began in 1982 with the Boeing 767. More recently Boeing has introduced the 777, which is the first jetliner to be completely digitally designed. The aircraft uses three-dimensional computer graphics and was the "pre-assembled" on a computer. The computer-generated assemblage eliminated the need for a costly, full-sized replicate. (Boeing 777 Program Background)