How much time do pilots actually spend actually spend piloting?
June 13, 2012 11:46 AM Subscribe
How much time do commercial pilots actually spend flying planes by hand these days?
I know that a lot of modern airline flying is highly automated. My question is, how much? When do pilots activate the autopilot - as soon as they're in the air? (For instance, when I watch Q400s climb out of YTZ, banking sharply away from the city, is the pilot flying, or watching a computer?) Similarly, I'm given to understand that autopilots usually handle approaches, but do they take the plane right through to touchdown?
Finally, under what circumstances in normal flight would an autopilot be disengaged? What about things like holding patterns above an airport? Enquiring nerds want to know.
I know that a lot of modern airline flying is highly automated. My question is, how much? When do pilots activate the autopilot - as soon as they're in the air? (For instance, when I watch Q400s climb out of YTZ, banking sharply away from the city, is the pilot flying, or watching a computer?) Similarly, I'm given to understand that autopilots usually handle approaches, but do they take the plane right through to touchdown?
Finally, under what circumstances in normal flight would an autopilot be disengaged? What about things like holding patterns above an airport? Enquiring nerds want to know.
Best answer: Short answer: depends.
Long answer:
"Commercial" pilot is a very broad term and can range from 747 captains to banner towing operations. Assuming you're talking about the Big Iron, modern autopilots are very sophisticated and are really only limited by how much you (the airline company) wants to pay for them.
Takeoffs are still done "by hand", since you want to be able to quickly respond to problems and stop the airplane on the ground if possible. Sometimes there's a problem and you deliberately don't want to stop, but to take off and troubleshoot in the air. Computers still don't have that kind of decision making capability, so that's left to the pilots. However, the actual control inputs are largely automated - for example, the pilot will push the throttles full forward, but the computer largely determines the actual amount of thrust the engines will provide based on the inputted weight and balance information. I believe around 500 feet off the ground is where the autopilot is engaged.
Landings can be totally manual, totally automatic, or somewhere in between. In good weather, my impression is that many to most landings will be by the pilot, with the computer picking up some of the slack (automatic thrust reverser and spoiler engagement, stuff like that). With the right equipment - on the airfield and in the airplane - the autopilot will land the aircraft by itself in very poor weather. "Very poor" in the case is something like a zero-zero landing (zero visibility, zero ceiling) - an unusual case but something that larger airliners such as those that cross the oceans are prepared for. Not every airport has the equipment necessary for these kinds of approaches. Holding patterns would definitely be done by the autopilot - it is really excruciatingly boring to fly in circles for any stretch of time. If the autopilot is doing the approach but not the landing, it may be disengaged at the decision height (basically where the pilot needs to decide whether to land or go around and try again).
In your example, YTZ has things known as Departure Procedures (DPs) which are published routes out of the airport. The autopilot would have a database of these DPs and could definitely fly the route automatically.
Things autopilots generally won't do - get you out of a tight situation. Traffic Resolutions in particular, I believe, are handled by the pilot (someone should correct me on this). Terrain warnings are another thing that the pilots end up handling.
Most of my experience is with smaller aircraft, so I can speak to their functionality a little better - big airliners have more bells and whistles, but it's really amazing how sophisticated autopilots have become for small airplanes.
There are two basic autopilot designs - rate-based and gyro operated. Rate-based autopilots take air data collected from the pitot-static system as well as heading data from the Directional Gyro (or magnetometers if they're installed) to figure out how quickly the airplane is turning and climbing and make appropriate compensations. Gyro-based autopilots will have two- or three-axis gyros built in to the system to supply this rate information. Coupled with nav radios, you can fly a fairly accurate course through the skies. If you have a GPS, the autopilot can shoot approaches for you.
Rate-based autopilots are a little twitchier than their gyro counterparts, especially in bouncy air - they tend to overshoot their corrections in the worst conditions where you would want an autopilot the most. Gyro autopilots stay rock steady in my experience.
So assuming you've just bought yourself a brand new Cessna with their top-of-the-line G1000 cockpit, your cockpit workload is going to look something like this:
Before arriving at the airport - plan your route of flight, check the weather
At the airport - file flight plan
In the airplane - receive flight clearance, put your route of flight into the GPS
After take-off - autopilot goes on at about 500 ft., set it to NAV mode and altitude capture
Cruise - the autopilot has flown the route and brought you to the correct altitude. Set throttle for cruise, autopilot will trim the airplane and fly the rest of the route.
Descent - arm the GPS for the appropriate approach, as instructed by ATC. Reduce throttle to descend.
Approach - Set throttle for appropriate approach speed
Decision Height - (assuming you've decided to land) disconnect the autopilot, flaps down, land that sucker. If you need to go around, disconnect autopilot, full throttle, climb out. At 500 feet above the ground, re-engage the autopilot. The GPS should have recognized the go-around and will direct the autopilot from there.
Small civil aircraft generally don't have autothrottles like the airliners do, so that's really the biggest thing you as pilot needs to worry about. The autopilot is smart, but not that smart - it will allow the airplane to stall if you don't give it enough power (airliners will automatically nose themselves over). The autopilot will also fly you right into the ground (and the soon-to-be smoking crater you will create) if you let it.
posted by backseatpilot at 12:20 PM on June 13, 2012 [13 favorites]
Long answer:
"Commercial" pilot is a very broad term and can range from 747 captains to banner towing operations. Assuming you're talking about the Big Iron, modern autopilots are very sophisticated and are really only limited by how much you (the airline company) wants to pay for them.
Takeoffs are still done "by hand", since you want to be able to quickly respond to problems and stop the airplane on the ground if possible. Sometimes there's a problem and you deliberately don't want to stop, but to take off and troubleshoot in the air. Computers still don't have that kind of decision making capability, so that's left to the pilots. However, the actual control inputs are largely automated - for example, the pilot will push the throttles full forward, but the computer largely determines the actual amount of thrust the engines will provide based on the inputted weight and balance information. I believe around 500 feet off the ground is where the autopilot is engaged.
Landings can be totally manual, totally automatic, or somewhere in between. In good weather, my impression is that many to most landings will be by the pilot, with the computer picking up some of the slack (automatic thrust reverser and spoiler engagement, stuff like that). With the right equipment - on the airfield and in the airplane - the autopilot will land the aircraft by itself in very poor weather. "Very poor" in the case is something like a zero-zero landing (zero visibility, zero ceiling) - an unusual case but something that larger airliners such as those that cross the oceans are prepared for. Not every airport has the equipment necessary for these kinds of approaches. Holding patterns would definitely be done by the autopilot - it is really excruciatingly boring to fly in circles for any stretch of time. If the autopilot is doing the approach but not the landing, it may be disengaged at the decision height (basically where the pilot needs to decide whether to land or go around and try again).
In your example, YTZ has things known as Departure Procedures (DPs) which are published routes out of the airport. The autopilot would have a database of these DPs and could definitely fly the route automatically.
Things autopilots generally won't do - get you out of a tight situation. Traffic Resolutions in particular, I believe, are handled by the pilot (someone should correct me on this). Terrain warnings are another thing that the pilots end up handling.
Most of my experience is with smaller aircraft, so I can speak to their functionality a little better - big airliners have more bells and whistles, but it's really amazing how sophisticated autopilots have become for small airplanes.
There are two basic autopilot designs - rate-based and gyro operated. Rate-based autopilots take air data collected from the pitot-static system as well as heading data from the Directional Gyro (or magnetometers if they're installed) to figure out how quickly the airplane is turning and climbing and make appropriate compensations. Gyro-based autopilots will have two- or three-axis gyros built in to the system to supply this rate information. Coupled with nav radios, you can fly a fairly accurate course through the skies. If you have a GPS, the autopilot can shoot approaches for you.
Rate-based autopilots are a little twitchier than their gyro counterparts, especially in bouncy air - they tend to overshoot their corrections in the worst conditions where you would want an autopilot the most. Gyro autopilots stay rock steady in my experience.
So assuming you've just bought yourself a brand new Cessna with their top-of-the-line G1000 cockpit, your cockpit workload is going to look something like this:
Before arriving at the airport - plan your route of flight, check the weather
At the airport - file flight plan
In the airplane - receive flight clearance, put your route of flight into the GPS
After take-off - autopilot goes on at about 500 ft., set it to NAV mode and altitude capture
Cruise - the autopilot has flown the route and brought you to the correct altitude. Set throttle for cruise, autopilot will trim the airplane and fly the rest of the route.
Descent - arm the GPS for the appropriate approach, as instructed by ATC. Reduce throttle to descend.
Approach - Set throttle for appropriate approach speed
Decision Height - (assuming you've decided to land) disconnect the autopilot, flaps down, land that sucker. If you need to go around, disconnect autopilot, full throttle, climb out. At 500 feet above the ground, re-engage the autopilot. The GPS should have recognized the go-around and will direct the autopilot from there.
Small civil aircraft generally don't have autothrottles like the airliners do, so that's really the biggest thing you as pilot needs to worry about. The autopilot is smart, but not that smart - it will allow the airplane to stall if you don't give it enough power (airliners will automatically nose themselves over). The autopilot will also fly you right into the ground (and the soon-to-be smoking crater you will create) if you let it.
posted by backseatpilot at 12:20 PM on June 13, 2012 [13 favorites]
Backseatpilot probably covered everything, but you still might want to check out Ask the Pilot (Patrick Smith) at Salon.
posted by she's not there at 12:34 PM on June 13, 2012
posted by she's not there at 12:34 PM on June 13, 2012
If you read the archive at http://flightlevel390.blogspot.com, you should get a picture for it.
There's more talk about landings, every one of which is described so well you feel like you're on the jumpseat, but this one of the descent into LAX is a pretty good exemplar both of the style and the workload.
Here's one that's about the workload at altitude. There's a lot more to piloting than holding a particular altitude and heading, which is what the autopilot does.
And for a look at what happens when it goes wrong (and what should have been happening in the first place) I think the Popular Mechanics article on Air France 447.
I don't have any expertise, I'm just fascinated by the whole field.
posted by ambrosen at 12:47 PM on June 13, 2012
There's more talk about landings, every one of which is described so well you feel like you're on the jumpseat, but this one of the descent into LAX is a pretty good exemplar both of the style and the workload.
Here's one that's about the workload at altitude. There's a lot more to piloting than holding a particular altitude and heading, which is what the autopilot does.
And for a look at what happens when it goes wrong (and what should have been happening in the first place) I think the Popular Mechanics article on Air France 447.
I don't have any expertise, I'm just fascinated by the whole field.
posted by ambrosen at 12:47 PM on June 13, 2012
I knew I forgot something. I also wanted to mention that use of the autopilot is also usually governed by the airline's particular standard operating procedures. Usually it involves imperatives to use the autopilot in certain situations, or explicitly disallowing hand-flying under certain circumstances. So its use will vary based on who you ask and where they work.
posted by backseatpilot at 12:47 PM on June 13, 2012
posted by backseatpilot at 12:47 PM on June 13, 2012
Yes, the pilot is flying when you see your Q400s climb and banking sharply away from the city. The name "autopilot" seems to confuse a lot of people -- it's not a robot pilot, cannot do landings and take-offs -- instead, it's more like a cruise control, keeps the plane flying at a constant velocity and heading, only.
posted by Rash at 1:31 PM on June 13, 2012 [1 favorite]
posted by Rash at 1:31 PM on June 13, 2012 [1 favorite]
keeps the plane flying at a constant velocity and heading, only.
This is entirely false. If you ask it to, the autopilot in most commercial airliners, Q400 included, can fly the entire flight path set up in the flight management system, complete with climbs, descents, turns, and speed changes, with no input from the pilot, and in many cases can fly the plane right onto the runway for landing. Here is a PDF describing the autoflight capabilities of the Q400.
backseatpilot is right about the answer to this question being very SOP dependent, and even then largely up to the discretion of the pilot. The only guidelines are that takeoffs are never automated, except for autothrust, up to a few hundred feet (I want to say I've seen 400ft minimum in one case, but am not positive). Cruise is highly likely to be automated. Landings are where autopilot usage becomes highly variable based on weather conditions, aircraft capabilities, ILS availability, airline SOPs, pilot training needs, pilot preferences, etc. You will need an actual airline pilot to be able to fill in these details.
Interestingly, the Q400 does not have autothrust. Did not know that. Every plane from A or B does though.
posted by kiltedtaco at 2:07 PM on June 13, 2012 [2 favorites]
This is entirely false. If you ask it to, the autopilot in most commercial airliners, Q400 included, can fly the entire flight path set up in the flight management system, complete with climbs, descents, turns, and speed changes, with no input from the pilot, and in many cases can fly the plane right onto the runway for landing. Here is a PDF describing the autoflight capabilities of the Q400.
backseatpilot is right about the answer to this question being very SOP dependent, and even then largely up to the discretion of the pilot. The only guidelines are that takeoffs are never automated, except for autothrust, up to a few hundred feet (I want to say I've seen 400ft minimum in one case, but am not positive). Cruise is highly likely to be automated. Landings are where autopilot usage becomes highly variable based on weather conditions, aircraft capabilities, ILS availability, airline SOPs, pilot training needs, pilot preferences, etc. You will need an actual airline pilot to be able to fill in these details.
Interestingly, the Q400 does not have autothrust. Did not know that. Every plane from A or B does though.
posted by kiltedtaco at 2:07 PM on June 13, 2012 [2 favorites]
I took the liberty of reposting your question for you in the airliners.net fora. I'll bet you'll get way better answers there than you could here.
I had to trim the question title slightly for it to fit in their limits.
posted by wutangclan at 3:02 PM on June 13, 2012 [1 favorite]
I had to trim the question title slightly for it to fit in their limits.
posted by wutangclan at 3:02 PM on June 13, 2012 [1 favorite]
Not a pilot, but I read a lot... Another thing to keep in mind is that autopilots have different modes that offer different levels of automation. At the lowest level is the "like a cruise control" mode Rash mentions: keep the wings level and hold an altitude. Then there are various command modes that allow for pilot inputs to be executed automatically. So a ATC might give the instruction "Bicyclefish 342: turn right heading 330, descend and maintain 7,000" and the pilot would dial 7,000 into the altitude window, a vertical speed of, say, -1,500 ft/min into the vs window (or let the aircraft determine the vertical speed based on a target airspeed, see below), and a heading of 330 into the heading bug. After engaging the appropriate modes, the autopilot will execute the requested commands. Lastly, there's the highest level of automation, often labeled LNAV/VNAV for lateral and vertical navigation. These modes couple the autopilot to the aircraft's Flight Management Computer (FMC) and allow the computer to specify complex 3D paths for the aircraft to carry out. In these modes, the FMC can be programmed for waypoint BIZZZ at 5,000ft, waypoint BUZZZ at 9,000ft, and waypoint BAZZZ at 12,000ft and the autopilot will automatically fly the specified path while making the crossing restrictions. This comes in really handy when flying complex departure or arrival procedures (see, for example, the BOACH4 departure out of Las Vegas). Sort of a variant on the LNAV/VNAV modes are the approach modes, which couple the autopilot to the radio signals processed by the instrument landing system so that the aircraft can descend down a tightly controlled approach path.
Any of these modes can be used with autothrust enabled, which controls the throttles and thus the amount of power produced by the engines to maintain a specified speed. Because speed and altitude are connected, you can combine the two to do things like a idle power descent (depending on the aircraft) where you bring the throttles down near idle and allow the aircraft to descend at the rate needed to maintain the selected airspeed.
ambrosen's "workload at altitude" link is a really good view of the complications that come up in the decision to use automation or hand fly. Another great resource on the subject if you have some time is a fantastic old (early 1990s I think) training video by a senior captain at American Airlines: Children of the Magenta Line. It is so titled because of the magenta lines automation systems draw on aircraft displays. His basic point is that there are different levels of automation and that the real value comes in knowing when to use each level to accomplish your goal. Use the autopilot when it frees you up to focus on scanning for traffic, monitoring, checking charts, etc..., but don't waste your time desperately trying to program the computer to do something that's more easily done manually.
posted by zachlipton at 3:31 PM on June 13, 2012
Any of these modes can be used with autothrust enabled, which controls the throttles and thus the amount of power produced by the engines to maintain a specified speed. Because speed and altitude are connected, you can combine the two to do things like a idle power descent (depending on the aircraft) where you bring the throttles down near idle and allow the aircraft to descend at the rate needed to maintain the selected airspeed.
ambrosen's "workload at altitude" link is a really good view of the complications that come up in the decision to use automation or hand fly. Another great resource on the subject if you have some time is a fantastic old (early 1990s I think) training video by a senior captain at American Airlines: Children of the Magenta Line. It is so titled because of the magenta lines automation systems draw on aircraft displays. His basic point is that there are different levels of automation and that the real value comes in knowing when to use each level to accomplish your goal. Use the autopilot when it frees you up to focus on scanning for traffic, monitoring, checking charts, etc..., but don't waste your time desperately trying to program the computer to do something that's more easily done manually.
posted by zachlipton at 3:31 PM on June 13, 2012
Response by poster: I took the liberty of reposting your question for you in the airliners.net fora. I'll bet you'll get way better answers there than you could here.
Thanks, wutangclan. Alas, the topic seems to have vanished - possibly deleted. Are you sure that's the right link? I was interested to see the results of your repost.
Thanks for all the input, everyone. This is fascinating stuff.
posted by bicyclefish at 5:54 AM on June 14, 2012
Thanks, wutangclan. Alas, the topic seems to have vanished - possibly deleted. Are you sure that's the right link? I was interested to see the results of your repost.
Thanks for all the input, everyone. This is fascinating stuff.
posted by bicyclefish at 5:54 AM on June 14, 2012
Your question on airliners.net may have disappeared, but slightly different versions of the same question has been asked, several, times, before. Each thread is very interesting, since you get a different set of pilots answering. The threads will often randomly veer off into other territory, so you might end up learning about stuff like RVSM airspace and how that affects autopilot usage along the way.
(I'm not trying to berate you for asking a common question, just trying to fill in as many perspectives as possible. It is a good question.)
posted by kiltedtaco at 9:23 AM on June 14, 2012
(I'm not trying to berate you for asking a common question, just trying to fill in as many perspectives as possible. It is a good question.)
posted by kiltedtaco at 9:23 AM on June 14, 2012
Dang...they deleted it. Too bad, coz when I checked last night, it was getting some really good discussion going. But yeah, probably because this has been discussed so many times before...they consider it a dupe. Or maybe they have something against me reposting your question. The threads that killedtaco has linked to are good reads.
posted by wutangclan at 10:40 AM on June 14, 2012
posted by wutangclan at 10:40 AM on June 14, 2012
One more update: The thread was not deleted, it was just moved to Tech/Ops where it belongs. Unfortunately, the question was phrased in such a way that it has just resulted in an unrelated argument about the role and importance of the pilot rather than the technical details of how the autopilot works. There are a few posts that are on-topic there, but I think you will find the previously mentioned links a little more relevant and less argumentative.
posted by kiltedtaco at 11:03 AM on June 14, 2012 [1 favorite]
posted by kiltedtaco at 11:03 AM on June 14, 2012 [1 favorite]
This thread is closed to new comments.
Their forums are usually very informative.
posted by fredericsunday at 12:01 PM on June 13, 2012