User Interface Issues and Automated Flight Control on the A320

Warning! These are notes from a short student talk on this subject. The data herein has not been verified. As the conclusions suggest, most of the problems observed herein have to do with user interface issues rather than problems with the concept of fly-by-wire. Thanks to some helpful readers for pointing this out

• Source: ???
• Original by Lea Wittie and Ryan Gerling (students)
• Some reformatting by Sam Rebelsky
• Note: at least one commentator who found this page has noted that the problems are overstated and recommends that those interested in finding out the real issues talk with pilots who fly A320s about them. [Added 10 April 2000]

• Information about the A320
• The accidents
• What was wrong with the A320
• The bandaid solutions
• Real solutions
• Conclusions to draw
• Interesting statistics

Information about the A320

• The A320 is an airplane with automated flight control.
• It uses a "fly by wire" system. The pilot's main interactions are with a computer, not with the plane. The pilot is surrounded by screens with flight data (airspeed, altitude, ...). Flying involves programming instructions on the computer. The computer makes use of facts like fuel efficiency and aifcraft safety to present safe and economical choices to the pilot.
• There is NO manual override on this aircraft

The accidents

• There have been 3 major crashes with A320s.
• 1) Pilot confused the data screens for flight-path-angle and vertical-speed). The plane went down into the side of a mountain.
• 2) Strasboug: The plane decended much too quickly on landing and smashed into the ground about 15 feet before the start of the runway.
• 3) While testing an A320, a pilot attempted to override the computer and had to rip out wires to do so. One feature which escaped the override attempt caused a crash when the pilot dove the plane towards the ground and tried to pull up at the last second. The computer refused to let the plane pull up and it crashed into a group of onlookers.

What was wrong with the A320

• There are built in landing maneuvers; one of the common ones had a defect. It caused abnormal behavior of the altimeter (you thought you were higher up that you actually were).
• The warning system went into effect only a few seconds before impact and was not even present on all planes.
• The monitors look alike and flight-path-angle and vertical-speed have the same format (easily confused).
• It's hard to see long term patterns using the computer data.
• The pilot is either EXTREMELY busy or EXTREMELY bored and during the flight they get a false sense of security (glass cockpit syndrome).
• Error and warning messages during data entry are often indecipherable and pilots often ignore them.
• Different pilots use different data entering methods; its hard to switch pilots all of a sudden.

The bandaid solutions

• The crashes were caused by inept pilots (duh!!)
• France put a warning device on its international flights to say when the plane descended too quickly. They felt this device was unnecessary on national flights because their pilots knew the terrain well. (The pilot recieved a two second warning before the craft smashed into a mountain side.) [This is not unique to the A320]
• The AIRBUS industry advised all companies using the A320 not to use the faulty landing maneuver.

Real solutions

• Investigate the crashes rather than immediatly blaming the pilots.
• Fix the faulty landing maneuver and the timing on the warning system. (Better planning)
• Make a better, more self-explanatory monitor display.
• Better, more explictit error and warning messages. Standardized data entry methods.
• Fix the glass cockpit syndrome. Any ideas??
• Train the pilots more.
• Too much automation may be a bad thing!! (Even the toilet flushes are computer controlled)

Conclusions to draw

• User interface is important.
• Bugs should be fixed, not ignored.
• Manual override is a good thing.

Interesting statistics

• "After 4 years in service, and 600,000 flying hours, the A320 has scored 3 major accidents and 177 lives lost. In 11 years, the Boeing 757 has flown 4 million hours with no fatalities." Don't worry, just pilot error