There has been a lot of talk in the media lately about aircraft automation. Apparently, The Machines are doing the flying and the pilots are sitting around drinking coffee and working Sudoku puzzles.
I’m happy to report the rumor of pilots relinquishing control to The Machines has been grossly exaggerated…
What can the autopilot do?
The most misunderstood system that pilots use is the autopilot. Autopilots do a great job of reducing pilot workload, but they can’t think.
Here’s what a typical airliner autopilot can do:
- The autopilot can steer the aircraft on a heading or pre-programmed course.
- It can be instructed to climb or descend the aircraft.
- When everything is set up properly, the autopilot (working with other systems) can help land the airplane.
The autopilot is a “dumb” system and cannot adapt to changing conditions during a flight. When flying into busy airports, heavy traffic and bad weather will require the crew to change the airplane’s direction, speed and altitude. Human pilots must manage these changes. Should we decide to use the autopilot to reduce our workload, we have to tell the autopilot what we want it to do. The autopilot may be physically manipulating the aircraft’s flight controls, but human brains are still doing the planning and management.
Typical Approach and Landing
Planning for any approach and landing begins during the cruise portion of flight. We discuss what runway we are landing on, the type of approach in use, the current weather, and other factors that will affect our arrival like taxiway closures and aircraft maintenance issues. We typically begin final approach using the autopilot and the airport’s electronic approach system. After flying through a few layers of clouds, we catch site of the runway about 4 or 5 miles out. The pilot flying will then turn off the autopilot and hand fly the jet to the runway for a nice, smooth landing. Hand flying (flying the airplane without the autopilot) is not only fun, it’s an important skill we need to maintain.
The majority of landings you’ll experience as a passenger are flown by hand. When the landing is especially smooth, be sure to compliment your flight crew as you exit. If it’s a rough landing, remember: It’s not the captain’s fault; it’s not the first officer’s fault… It’s the asphalt!
The Autoland Approach and Landing
Sometimes, heavy fog or snow will cause low visibility at the destination. So low that we can’t see the runway until the main wheels have touched down. The game now changes. With visibility this low, it’s not possible for a human to hand fly the airplane to the runway. The flight crew needs to perform an “autoland.” Our previous 5 minute approach brief now turns into a lengthy review of a multi-page checklist. A colleague of mine describes it like this: “An autoland at our airline is a well orchestrated ballet involving pages of preparation.”
To get an idea of what we can (and can’t) see during a low visibility autoland, compare the two flight deck images above. Both are taken at about 100′ above the ground. The bottom image shows what we see with 1/8 mile visibility caused by fog. Look very closely and you can see the runway and some lights (click the image for a larger view). Now consider that we are moving towards this runway at over 160mph. We definitely need a little help from our automation to land the airplane.
A safe autoland requires that both aircraft and flight crew work together perfectly. As the autopilot brings the airplane closer to the runway, our eyes are carefully scanning for any anomaly, warning flag, or status message that might indicate a problem. With the exception of a few well rehearsed call-outs, the cockpit is dead silent. After touch down, the autopilot will continue to steer the aircraft down the center of the runway until the captain disengages the automation and takes over to taxi.
The Autoland Button? Sure! These days, those airliners land themselves!
I often hear non-aviation folks talk about pilots simply pushing a button to make the airplane land itself. If we have an autoland button, I haven’t seen it!
There are several systems on our airplane that must be properly set up before the aircraft can make a successful autoland:
The approach frequency, speedbugs, autobrakes, landing gear, flaps, spoilers, autopilots (we have three), altitude select, and missed approach procedures all must be programmed, armed, engaged, dialed up, and loaded. Whew! We are busy during every approach, but even more so before and during a low visibility autoland.
An “autoland button?” Nope.
Planning for a failure.
Airliners are really reliable. Crews successfully perform autolands in bad weather dozens of times a day worldwide. We rarely have problems with them (maybe one in a bazillion?). However, when we prepare for this type of approach, we plan for failure. As they say, sometimes stuff happens. What happens if an engine fails during the approach? What if the airport’s electronic guidance system goes kaput? What if one of our electrical systems goes haywire? We practice all these scenarios in the simulator. During a real autoland approach, we aren’t on a coffee break; we are ready and waiting for trouble. If a problem does occur, we will immediately take manual control of the airplane and climb away from the ground. Once we are at a safe altitude, we can address the problem then fly the approach again to make a safe landing.
So what’s the answer? Can an airliner land itself?
When properly set up, the autopilot and other automated systems can land an airliner on the runway – and pretty darn smoothly, too. As impressive as that sounds, these systems still require humans to plan, set up and monitor them. They also require humans to intervene when things don’t go exactly as planned. Bottom line… the pilots have not relinquished control to The Machines. You’re in good hands.
A very special thanks to Zach Williams for creating the B-767 flight deck images used in this post! Zach stayed up late and was exceedingly patient with my obsessive/compulsive demands. Images were rendered using Microsoft Flight Simulator X with Flight1 Software’s Level-D 767.