Passengers on a Flybe plane got quite a scare earlier this year, when an autopilot error meant that their plane went into a nosedive almost immediately after take off.
It's the worst case scenario for nervous flyers - that something goes wrong, and the whole plane simply falls out of the sky and crashes - but most people are reassured by the idea that there are plenty of systems in place to make sure that the plane arrives safely. It's not just the pilot and co-pilot up there doing all the work, after all; the onboard computers are what are actually in control the majority of the time.
Autopilot is usually engaged for most of the time while planes are at cruising altitude - the pilot deals with takeoff and landing, but it's the autopilot system that usually maintains altitude and deals with the route (that the pilot programs in). However, when autopilot goes wrong, it's the captain that is in charge of taking control and keeping the passengers safe - which happened on a recent Flybe flight from Belfast to Glasgow.
The Bombardier Dash 8 Q400 only had 44 passengers on board (the aircraft holds 74) when it took off from Belfast City Airport on January 11th, headed to Glasgow. When the plane hit 1,500 ft, autopilot engaged - however, the target altitude was mistakenly set to 0 ft, so the plane immediately started to nosedive. The aircraft fell around 500ft in just fifteen seconds before the pilot was able to regain control and bring it back to an appropriate altitude.
During the dive, the plane was plummeting up to 4,300 ft per second - and if the pilots had been even a few moments slower to bring it back under control, there is little doubt that it would have crashed. However, no one was hurt, and the plane was able to land at Glasgow with no further incidents. The Air Accidents Investigation Branch (AAIB) found that the issue arose when the pilot chose a specific mode of autopilot, and the airline has introduced new policies including a different pre-flight checklist to make sure that this does not happen again.
Thankfully, this was a near-miss, rather than the tragedy it could have been, and it's far from common. It's also worth noting that the problem here was human error, the wrong autopilot setting was chosen. This is common for airplane mishaps - the vast majority are caused by humans making mistakes, not the systems that we use to keep planes in the air... so next time you fly, don't worry about the autopilot, just get a good look at the captain!
Source: The Sun