Volume 117 >> Issue 41 : Friday, September 12, 1997

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First Dinner in da Vinci Series Focuses On Aircraft Automation and Accidents

Professor of Aeronautics and Astronautics R. John Hansman Jr. PhD '82 spoke to and dined with a group of 17 students yesterday evening in Ashdown House's Hulsizer Room as part of Tau Beta Pi's Leonardo da Vinci dinner series.

Hansman spoke about difficulties with automation in aircraft systems.

The MIT chapter of TBP, a national engineering honor society began this series celebrating the life and work of Leonardo da Vinci to "foster a spirit of liberal culture at MIT."The private dinner talks will bring together several faculty members and about 20 TBPmembers every Thursday evening for a dinner and lecture, said TBP PresidentPanayiotis I. Kamvysselis G.

The dinners, which feature cuisine from a wide variety of cultures, are funded through the proceeds of the annual TBPcareer fair. Last night's dinner was entitled "Traditions of Native American Cooking."

Human factors needed in design

During an introductory half-hour lecture, entitled "Problems with Automation Systems in Commercial Aircraft, or Why I Hate to Reboot in Midair," Hansman, a pilot and a specialist in human factors engineering in aircraft, spoke of the need to address human issues in aircraft design.

While the space shuttle is the only flying vehicle that requires rebooting in flight because it doesn't have enough memory to hold all its commands, other aircraft have experienced problems with technology in the cockpit, Hansman said. As automation has increased in aircraft systems, pilots must learn new skills not formerly needed in a switch and lever-based cockpit.

While new planes have significantly lower accident rates than older, first-generation aircraft, controlled flight into terrain remains the leading cause of crashes, Hansman said. In this instance, "You take a perfectly good airplane and fly it into the ground," Hansman said.

In fact, two recent crashes of modern aircraft - the Air Inter Airbus Industrie A320 and the American Airlines Boeing 757 - were directly attributable to the automation system of the aircraft, Hansman said.

Hansman then went into further detail. For example, in the Airbus accident, the pilot of the aircraft selected a mode of the autopilot that caused the plane to descend at 3,200 feet per minute instead of on a 3.2° downward slope.

While the mistake would have been observed very quickly during the day due to the slope of the aircraft, the pilots were relying completely on instruments, Hansman said. In addition, the captain of the aircraft was using a display which did not display the feedback indicating that the plane was in the wrong autopilot mode.

Essentially, there was "insufficient feedback" to the crew, and the airplane flew into the ground. In later tests, only two out of 12 pilots tested were able to discern the mistake under similar conditions, Hansman said.

Other problems plague aircraft

Other potentially more humorous cases illustrated other problems in modern aircraft design. For example, one operator's A320 fleet began rolling uncontrollably in flight, Hansman said.

The problem was traced to the joystick-style controllers located on the side of the cockpit, Hansman said. Over time, pilots "ended up pouring coffee into the stick"when their cups in the adjacent cup holders spilled. Eventually, the devices that monitor the joystick were degraded, causing the uncontrolled rolls, Hansman said.

Many of the problems of modern aircraft come from the increasing complexity of their computer systems. The newest commercial aircraft introduced in the world market, the Boeing 777, contains the computer capabilities of about an Intel 386 processor, Hansman said.

However, many new computer systems are "programmed based on older systems"to save on expensive certification costs, Hansman said. This leads to unwieldy systems that may not be completely error-proof.

As a result, "humans are forced to compensate for errors in the system,"thus increasing the workload on the crew. While many pilots can easily handle the difficulty of dealing with an imperfect system, other less-skilled pilots "are along for the ride"and may make critical mistakes, Hansman said.

Discussion over planes, students

After the half-hour lecture, the assembled students and faculty were able to mingle and discuss aviation and faculty-student affairs.

One problem that hinders interaction between faculty and undergraduates through residence groups is the differing schedules that the groups have compared with faculty members, Hansman said.

Others agreed. "We had a faculty associate with our dorm ŠThey felt they weren't doing anything because our schedules conflicted,"said Brandon W. Porter G.

"The easiest relationships tend to be around research,"Hansman said. The dinners "are exactly the kind of thing we should do more of."

Discussion also focused on Hansman's work leading the International Center for Air Transportation, as well as his role as chair of the Task Force on Student Life and Learning.

The interaction was exactly what organizers of the event had intended. "Ithink that's exactly the spirit we wanted to have,"Kamvysselis said after the dinner, "Ithink it went really well."