Yes, trim is the thing I was thinking was on the wings (I learned about from one flight lesson in a little Cessna many years ago).
“Flight computer” provides information (some from sensors, some calculated based on sensor or entered information) but doesn’t control the aircraft (at best, it can provides suggestions to the pilot). On the airbus A320 (in Captain Joe videos) I’m thinking it’s a panel on the center console, near the pilots knee. It has a numeric keypad, the letters A-F, some other keys, and a small display with some hotkeys around the edge.
I said “flight computers and autopilots” because I’d assumed flight computers were in use or available before electronic autopilots. … I am aware there was a gyroscope-based autopilot that was invented just a few years after the Wright brothers’ flight.
The thing you’re calling a “flight computer” is properly a “flight management system” = FMS.
It’s mostly a navigator. It has a database of the locations of all the relevant nav points and when coupled to a source for aircraft position and speed can figure out which way to go to get someplace and how long it’ll take to get there.
Its other major function is performance computations. It knows about weight limits, fuel consumption depending on altitude and other variables, etc. So if it knows how much fuel you start with, it can compute how much you’ll end with according to the current plan. If you change the plan it’ll promptly recalculate the expectations all the way to landing.
It’s a big labor saver when significant changes are needed enroute. But for the typical case of HQ creating a plan for us to get from ABC to DEF that is then flown pretty much as planned, there’s very little info coming from the FMS that we don’t already have on our old-fashioned paperwork.
It does provide labor saving in that we can keystroke in the route before we leave the gate. Then HAL (as we often call it) will guide the plane from nav fix to nav fix without us having to fiddle with radio beacons and such. In essence it becomes the “master brain” doing the strategic control while leaving the detailed “pull back to go up” flying to the autopilot and its muscles. Then our job becomes watching the watcher, changing the plan as necessary, and intervening when HAL starts doing something stupid.
For the cruise portion of the flight, HAL reduces error. For the more dynamic departure and especially arrival environment, there comes a point where it’s usually better to simply cut HAL off and operate without his “help”. Keeping him synced up with a rapidly evolving tactical plan negotiated between us and ATC all the while we’re closing rapidly towards the ground eventually becomes more trouble and distraction that it’s worth.
Knowing when and how to switch between fully automated versus fully manual control and the several intermediate mixed levels is an evolving science and art. People have died by driving the computer when they should have been driving the jet. And vice versa.
IANAP, but had a coworker who used to like to tell stories about his days as a pilot in the US Marines - I remember him saying they were taught that when in trouble, their priorities in descending order of importance were “1. Aviate, 2. Navigate, 3. Communicate.”
Ah yeah, so that’s a flight management computer, also known as a flight management system. At its heart it is a navigation computer. Life without it would mean only flying airways that are served by radio beacons and having to tune frequencies and dial up courses by hand. There would be some periods in flight where you’d be out of range of the radio beacons and would have to use dead reckoning (set heading based on estimated winds) until you came within range of the next beacon. It’s not rocket science but is not nearly as accurate as FMC computed position based on all available sensors. The lack of the FMC would also mean more manual calculation of things such as fuel remaining, current weight, landing weight, etc. Most pilots still calculate these things manually, or at least estimate them, as a cross check of what the FMC is saying anyway.
I have flown some BAe146s that had a GPS nav unit but it wasn’t really a flight management computer and it couldn’t be coupled to the autopilot, meaning the pilot had to operate the autopilot in heading mode, manually adjusting heading to stay on the track calculated by the GPS.
With the small airplanes, and so I imagine with the really big ones - much of the grunt work is done on the ground. They have a pretty good idea of the distribution of and weight of passengers and luggage, fuel etc. that’s not something you wok on after the doors are closed before takeoff. Similarly, you have a pretty good idea of the path, winds aloft strength and angles, and so roughly what headings you have to fly. These adjust as necessary. You have to try really hard or be pretty negligent to overload or load out of CG a large airliner. They are designed and procedures are set to not do so. Also, while flying you use feedback from the route to update the flight plan (which on a large airliner, included a navigator). So indicated air speed plus distance covered between points told you wind speed. This allowed you to calculate how fuel was doing, but airlines by law have to have a pretty good reserve, and you keep an eye on fuel levels, so you’ll know well before it’s too late 9we hope) if fuel is a problem. Another part of the predetermined plan is where to divert at any point if there’s an emergency.
So the only thing to do is fly, and worry about flight plan once airborne. Air traffic control will get you most of the way to flying altitude (and today, most of the trip). As others mention, just run the controls to match the flight plan - this airspeed, this heading,this altitude - until we reach this waypoint; etc. And as also mentioned, flying, like driving while staying between the dotted lines, was mostly a matter of paying attention to the instruments and/or looking out the window and adjusting accordingly. IIRC there was a trim and some small aircraft (am I remembering this right?) had a similar rudder tab adjustment. Set those properly and you could take your hands off for several minutes and the aircraft would maintain direction and altitude. I recall some instructors using only the trim wheel to maintain altitude… if we appear to be descending slightly, adjust us up a little more…
Yes, I guess that’s an entrenched standard aviation wisdom. In my little glider club, the instructors are always beating that us into our heads too.
If you get the plane trimmed right, it can pretty much fly itself. I’ve posted a video of me flying a glider in quite a few threads by now where there was some relevant point to be made … (here it is yet again) Early in the flight, the pilot in the back seat (heard but not seen in this video) remarks, twice, that the glider can fly itself better than the pilot can. He demonstrates that the glider will fly itself in “Look, Ma, no hands” mode. Shortly afterward he has me try it, during a fairly steeply banked turn. By pulling the trim back, the nose of the glider stays up, and it also remains in a stable steep turn, hands off!
I was flying with my dad once in a Cessna and he showed me something really interesting. We had the plane trimmed and balanced, were flying straight and level, 80mph, hands and feet off the controls. He told me to push the throttle forward a bit. I did. The plane did not speed up, it started climbing. I pulled the throttle out and we leveled off. Pulled it out some more and we started descending; all hands-off and 80mph. I don’t know if it’s true in all planes and all conditions, but there’s a way of thinking that says that the yoke (or stick) and elevator trim control the plane’s speed, and the engine controls make it climb or dive.
Interesting that there’s another BAe 146 pilot here. My dad had some time in those (or it may have been the Avro RJ by then).
Yes, here’s a video where a pilot shows a large folder of information he receives before a flight. It has things like takeoff speeds, the planned route with altitudes and airspeeds, what airports to divert to in an emergency, weather info, and more.
Flying short haul for a small company that doesn’t have a flight planning department, we have access to the same information but we print it ourselves and tend to filter it prior to printing. We will look at the weather maps and if there’s nothing interesting we just won’t print it. Our flight plan, fuel plan, flight log and anything else to do with navigating is on two, sometimes three, pieces of paper.
Other stuff they had as part of their package, such as the take-off data for the airport, we just have in a book that stays in the aeroplane. It’s not specific to a flight but covers the likely range of scenarios that we would encounter through the year.
Navigation charts are our own personal items with most of us using an iPad app rather than paper.
Yes you basically trim for a speed. If you add power you go faster which creates more lift over the wings and you climb, if you reduce power the opposite happens. One way of descending using the autopilot is to set a lower altitude in the altitude window then select “level change”. The auto throttle retards the thrust levers towards idle and the autopilot attempts to maintain the selected speed in the only way it can, by pitching down. This is not quite the same as what was demonstrated to you, but very similar.
Do you know if he liked it? I’ve been flying it for the last 6 years and I don’t know if I like it or not. A bit of a love / hate relationship.
Takeoff speed… A pilot generally won’t be allowed to fly the aircraft by the owners - unless it’s his own - without some proficiency practicing with it - or nowadays, for big aircraft, a simulator. Thus you should know the rotation speed (lift nose) take off and climb speeds, approach speed for landing with various flaps, etc. Just before you do it is not the best time to be looking it up these details. Of course with commercial pilots flying big jets (or back in the day, props) they would likely be only flying one or two types of aircraft, so they would have been very familiar with key numbers, as well as the controls.
But not necessarily. The only large airplane crash I saw was about 1970 in Toronto (and from miles away, you could see it halfway across the city). I read an analysis of the crash a few years ago. Apparently with a DC8 there were different flap lever configurations, and in this case a copilot familiar with the wrong setup deployed the air brakes (?) 50 feet up. The plane bounced, dropped an engine, and flew off to attempt a go-around. You could see a big ball of flame going across the horizon until it finally crashed. All because two versions of the aircraft had different configurations of a key lever.
Our standard joke has always been “We can’t leave until the paperwork weighs more than the airplane.” The other version, since it’s printed as a long strip on old-style fanfold paper with the pinfeed holes along the side, is “We can’t leave until the paperwork is longer than the airplane.”
The fixed-size content ends up being about 8 printed pages. Then comes the variable content which depends on how long the route is and how convoluted the weather, plus whether the airports at either end are big complicated places or small Podunk fields. A quick hop between two small airports is worth probably 4 extra pages. A 12-hour jaunt between two major city airports is more like 30 extra pages.
We’re in the midst of switching all this to iPad downloads of the same text content in lieu of physical paper. Plus a new and vast pile of weather info downloaded in graphical form. So we’re carrying less paper, but actually have more total preflight info to supposedly review in excruciating detail and be fully cognizant of.
We’re also moving into having WiFi in the cockpit so we can even update all this mound of info in near real time as needed. Which is not really useful for a short hop but can be invaluable when you’re arriving some place 12 hours after your paperwork was printed and in the meantime the weather has not been behaving as predicted.
You know, I never thought to ask him that specifically. Part of his job was to pick up new RJs at the factory in England, do an acceptance flight on behalf of the airline, take part in a conference call to transfer ownership, and ferry them to the U.S. They probably still had that new plane smell.
It’s interesting that Charles Lindbergh made a solo flight from New York to Paris in 1927 without ANY of that stuff. Couldn’t even look forward without using a small periscope.
Before GPS, we had other navigational aids such as LORAN, ADF, and VOR beacons. Then there is good old pilotage, which is using a combination of dead deckoning and landmark/terrain spotting.
I used to participate in an annual air rally which was a precision flight planning/dead reckoning navigation contest. It was common for pilots to fly the three-legged route a couple of hundred miles long and land at the destination within a minute or two of the flight plan, using no aids other than their MKI eyeballs and a winds aloft report. And if you didn’t have the winds aloft or they were inaccurate, you could calculate that in flight and adjust your flight plan accordingly using a circular slide rule (the E6B flight computer or ‘whiz wheel’).
Some great information, all. I wasn’t aware the weather reports and predictions for aviation were accurate enough you could trust one set of data for more than a few hours. Or are variations that important? Does it matter if your headwind (or crosswind) is 20 knots rather than the 10 you expected?
Also, how accurate is the saying “If you can see it with your eyes, you’re probably too close” (‘it’ referring to another aircraft)? I assume it’s mostly for the big airliners.
Enroute crosswinds are essentially immaterial. Except when unusually large changes over a short distance are associated with turbulence. An unexpected headwind increase of 10 knots would put you 10 miles behind the plan at the end of an hour of cruise. 10 miles represents less than 90 seconds’ flying. Even over a 12 hour flight it’s only going to add up to about 18 minutes. We have more slack than that in our planning. So a 10 knot error in headwind expectations is also negligible. 20 or 30 knots off forecast starts to matter. But is exceedingly rare these days.
Where unexpected winds matter is in arrival. A common scenario is something like the wind blowing from the east until a front is expected to pass and thereafter the wind will be from the west. At the time of frontal passage there may be strong gusts and there may be a 10 minute pause in operations while they switch which direction the airport is operating. If you were expecting to arrive before or after and instead the front arrives just when you do, you’ll maybe get wrapped up in the delay. In the US at least, many fronts also come with thunderstorms which can stop an airport for an hour. Overall the weather folks are real good at predicting what will happen where. The when is often the weakest part of their predictions.
There are also a few airports where winds strongly affect throughput or whether the long or short runway is available. Or whether the wind-compatible runway is equipped for crap weather landings or not.
Naturally when operating into unsettled conditions, or into airports that are especially weather sensitive, everyone involved at HQ and in the cockpit are paying extra attention.
Another issue more common in fall or winter is temperature. If the temp drops enough in humid conditions fog will form or rain may turn to wet gloppy snow. Any time the temp forecast shows conditions should be just on the warm side of fog or freezing that’s a wakeup call.
As to seeing other airplanes we do it all the time. In cruise they go by big enough to know what kind and read the logos. What they don’t do (or at least really, really shouldn’t do :)) is go by close at the same altitude. On arrival and departure at a hub it’s very common to see a handful or airborne jets at a time, and be navigating yourself to follow or avoid one or another.
Naturally, how far away a big jet can be seen depends on the clouds. In hazy or cloudy conditions jets can go by 1000 feet above or below with zero lateral offset and never be seen. All we see is the dot on our traffic scope getting closer to our dot at 1000mph until they cross through each other. OTOH, on a very clear day where jets are dragging contrails we may see each other 100 miles out; a full 6 minutes before we pass.
I was on a small two-engine prop plane in Venezuela once, returning from a trip to Angel Falls. I want to say it was a Dornier because they’re sort of funny-looking and it stuck in my head. I was in the aisle seat in the front row and the cockpit door was open. It was clear that one pilot was a vet and was explaining things to the other–I don’t speak enough Spanish to have followed exactly, but the older guy would point to an instrument and say something, the younger guy would clearly be asking a question; there was occasional reference to a printed manual.
Then we begin to descend. At this point the pilot unplugs his radio transceiver, which is on his side of the plane, and hands it to the junior guy. The senior guy is looking at something and doesn’t see what I see: Instead of plugging in the transceiver on his side, the trainee just sets it down next to him, then takes the stick. I’m thinking, that can’t be right. But what am I gonna do, interrupt two pilots to ask questions in a language I can’t really speak, about flying a plane, which I don’t know how to do?
The trainee is now flying with occasional comment from the senior. But I can see out the front window, and it looks to me like our descent is really steep. The radio starts spitting out questions or advice from the ground. When the younger guy doesn’t respond, the older says something angry to the younger guy, like “why don’t you answer?,” in response to which * he holds up the disconnected transceiver and shrugs.* The older guy, instead of doing something, starts berating the younger guy. Meanwhile it looks to me like we’re pointed straight at the ground. I don’t remember being afraid, but I thought we were going to crash for sure.
Finally the older guy grabs the stick himself, pulls us up sharp, three hard bounces and we’re on the ground safely.
As LSLGuy says, 10 knots is nothing. The only time I get concerned by the en route wind is when there is a very strong cross wind. A small change in wind direction can cause a large change in the head / tail component. If you’re tracking north with a 120 knot crosswind from the west, a 15º change in either direction can see a 60 knot change in head / tail component. If the plan was based on 30 knots tailwind but you actually get 30 knots of headwind then you may need to think about fuel a bit more seriously than you normally would.