The flight crew on Asiana Airlines Flight 214 relied too much on automated systems rather than on monitoring flight conditions themselves. investigators said. (Reuters/NTSB)

On a July morning in 2013, Asiana Airlines Flight 214 prepared to land in San Francisco.

A few miles from the airport, its pilot chose the wrong autopilot setting, and the plane stopped tracking its own speed. The flight crew didn’t realize that the plane was moving dangerously slow — and descending too fast — until it was too late.

The Boeing 777 struck a seawall short of the runway, breaking off its tail. The plane — carrying 291 passengers — slid down the runway, spinning in almost a full circle. Three people died, and 49 suffered serious injuries.

Investigators blamed the flight crew’s reliance on automated systems, such as autopilot, as a cause of the crash.

The crash is a telling example of the perils of too much of a good thing in the cockpit — automation.

While flight experts credit automated systems with helping improve safety and making airline operations more efficient, they caution that an overreliance on automation leaves pilots unprepared for tricky situations that require their expertise.

A new government report echoes the warnings on overrelying on automation, and says the FAA needs to do more to make sure that airlines ensure their pilots effectively monitor automated systems and keep their manual flying skills sharp.

The report warns that as aviation technology advances, pilots will have fewer chances during flights to keep their manual skills sharp. These abilities will likely diminish, which could prove disastrous in a situation where a human pilot needs to take control.

The chief pilot on Flight 214 said the airline recommended using as much automation as possible. One of the airline’s simulator instructors told investigators that pilots avoided flying manually over concerns they might do something wrong, and the company might blame them for a less-than-perfect landing.

“What we’ve learned from aviation is that just because some amount of automation is good, it doesn’t always mean that more automation is better,” said Nicholas Carr, author of “The Glass Cage,” which details the perils of automated systems. “And really there’s a sweet spot you have to find where you use automation to relieve the pilot of some amount of workload.”

If pilots are relieved of too much work, their attention will start to drift, and they won’t get enough practice at manual flying, Carr said.

Finding that sweet spot of just enough automation is difficult due to constant developments in aviation technology. With each advancement, airlines must rethink how to split labor between humans and machines.

“There’s still more we need to know about how much manual flying is optimal to make sure that pilots maintain their situational awareness in their skills,” Carr said.

The report says the FAA doesn’t have a sufficient process to assess a pilot’s ability to monitor flight deck automation systems and their manual flying skills. It says the FAA hasn’t ensured that airline training programs for pilots focus enough on manual flying skills.

It’s not even clear how much automation is used by pilots. In the report, FAA officials estimate it is 90 percent, but said there’s no industry-wide analysis to validate that. Only two of the nine air carriers visited by the authors analyzed how often pilots use autopilot. And two of the airlines actually discourage pilots from flying manually under normal conditions.

“There’s no question these features have made flying safer. Look at the dramatic rise in the number of flight hours and the dramatic descent of the number of accidents,” said David Mindell, a pilot and author of “Our Robots, Ourselves: Robotics and the Myths of Autonomy.” “But they have dangers when you’re too reliant on them.”