It is raining here and rather than doing something healthy and productive. I decided to sit in front of this laptop and visit liveatc . com and flightaware . com. (not affiliated in any way. Mods move as you see fit).
So my ignorance is showing, what does these mean?
:: UAL 385 B739 30000 450 IAH SFO 01:42AM ::
I get United Airlines is leaving Houston to San Francisco.
385 is perhaps the flight number? Or just a call sign?
What the heck is a B739? Color me confused.
United Airlines flight 385, Boeing 737-900, 30,000 feet altitude, Houston (IAH) to San Francisco (SFO).
I’m not sure what the 450 means.
IANAP, but we have many that can add to or correct anything I say here.
B739 is likely the Boeing 737-900.
30000 would be the altitude, 450 the speed in knots, IAH and SFO the origin and destination, and the time the estimated arrival time.
UAL = United Airlines
385 = Flight number
B739 = Boeing 737-900
30000 = altitude (feet)
450 = speed (knots)
IAH = Houston
SFO = San Francisco
01:42 = Arrival time (local)
Totally ninja’d 
450 is the speed.
Double ninja’d!
The speed display is groundspeed rather than airspeed.
Doh! I totally should have picked up that 450kt was the speed.
Holy cow! Thank you all.
I am being a back seat wanna be pilot. Appreciate the info.
Been wishing I was up there flying above the clouds on a day like this.
That is a beautiful plane.
Another dumb question if I may - regarding ground speed versus airspeed. How are they measured? And are they much different from each other? Curious.
Ground speed is measured by ground radar (or sometimes on-board GPS on the plane itself). Air speed is measured by the velocity of air passing through pitot tubes on the aircraft.
There are several types of airspeed.
True airspeed, or TAS, is the actual speed of the aircraft through the air. This is important for working out how long it will take to get from A to B but not much else. It is not measured directly but calculated by taking indicated airspeed and adjusting for pressure and temperature. A modern flight computer handles these calculations automatically while in years past a circular slide rule was used (and still carried by some) to get a “good enough” approximation.
Indicated airspeed, or IAS, is the speed of the aircraft as indicated to the pilot on the airspeed indicator (hence the name). This is derived by measuring the dynamic pressure (due to forward motion) of air entering a small tube sticking out from the fuselage.
Indicated airspeed is essentially a measure of how many air molecules are whizzing past the plane at any time. At sea level the airspeed indicator is calibrated to read as near as possible to true airspeed but as you go higher and the air becomes less dense, there are fewer air molecules whizzing past for a given true airspeed which means the indicated airspeed progressively under reads the higher you go. At airline altitudes this is very significant, in the order of a 150 knot difference. But, because the wings work on the number of air molecules whizzing past rather than how fast they are moving, indicated airspeed is the primary indicator of performance at any altitude.
There are other types of airspeed, calibrated and equivalent airspeed, but they are very similar to indicated airspeed and can be ignored unless you want extra detail. There is also Mach number, which is true airspeed as a fraction of the local speed of sound. This becomes more important the closer your speed gets to the speed of sound.
Ground speed is the speed of the aircraft across the ground and is the true airspeed as affected by the wind. This speed is measured directly either by GPS or any other means of positive ground position fixes. In zero wind an aircraft with a TAS of 450 knots will have a ground speed of 450 knots. With a 50 knot headwind, that same aircraft would have a groundspeed of 400 knots and so on.
So groundspeed and true airspeed are all about navigation, while indicated airspeed is all about performance such as best gliding speed, best economy speed, best range speed, best endurance, stalling speed, etc.
I’m surprised they’d give the arrival time in local instead of zulu.
Boeing is working on their next generation of 737 (not to be confused with the 737 Next Generation, which was the previous generation) and they’ve been lengthening the fuselage, as airline builders so often do. They reached the point where the tail could strike the ground on takeoff, and there was no simple fix. I think they’ve decided on a design where the main landing gear will either be longer or the wheel will be moved slightly aft, but still retract into the same wheel wells as the current design.
A tail strike is a risk on pretty much all commercial jets. The deal with the longer versions is that the risk of tail strike is greater because you don’t need as much nose up angle to do it. Eventually if you stretch them out long enough the tail strike risk becomes unacceptably high and you have to design around it. The Dash 8 300 was a 3 meter stretch of the 100 and 200 and kept the same undercarriage while the 400 was a further 7 meters longer and required a redesign of the landing gear.
Forget all that. Get yourself outside in the fresh air and GO DO IT! Get yourself to a flight school at your local General Aviation airport and get yourself a flying lesson in a 2-seater or 4-seater airplane! I think all flying schools offer an “introductory lesson”.
Another choice: Find a nearby gliderport and get a glider ride or an intro lesson. Much less expensive, generally, than flying powered aircraft. You can find umpteen YouTube videos to show you what it’s like. Try these:
[ul][li] Intro Lesson: https://www.youtube.com/watch?v=WAQy6POtmkc[/li][li] Lesson 1: https://www.youtube.com/watch?v=DXn5advJoyI (I guess he numbers the intro “Lesson 0”)[/li][li] Lesson 2: https://www.youtube.com/watch?v=omIuvkxetI8[/li][li] Lesson 3: https://www.youtube.com/watch?v=CtvURu094J0[/ul][/li](No, I’m not Dante Otero. I don’t even know who he is. I do, however, recognize the unseen instructors by their voices.)
OTOH, guess who this is (in the floppy hat) in this video: https://www.youtube.com/watch?v=IhBx9bhFIGs (Not exactly an intro lesson.)
Another possibility (but may require some “connections”), get yourself a buddy who flies, who will take you flying once in a while. A great many GA pilots will take friends flying with them and let said friends try their hand at the controls, and live to tell about it! I myself have had this opportunity several times lately (and another flight coming up this Sunday) and it’s a gas!
Don’t just sit there. Go flyin’!
Boeing just revealed a novel solution for the 787-10. It too was getting too long for the gear and had a high tail strike risk. So they tweaked the flight control software to prevent the pilots from dragging the tail. At least until some determined pilot locates the glitch in said software. 
Sadly they can’t apply that solution to the 737-10. Both because it’s not fly-by-computer and because the damn thing’s so long and so low-slung that they can’t get enough rotation angle to lift off or touch down at anything like an acceptable speed in an acceptable length runway.
All sorts of mechanical jiggery-pokery is being looked at as they try to shoehorn the 737-10 into existence without doing a center wing box redesign.
Perhaps the most surprising thing to me is that, knowing the challenges short gear has caused them while growing the 737 in every model since the -200, they deliberately designed the 787 series as low-slung too. I’ll be damned if I understand why.
It’s amazing how much life Boeing has gotten from the basic 737 airframe. I wonder if the original designers gave even a moment’s thought to landing gear and how much the fuselage could be stretched before tailstrikes presented too much of a risk. I read somewhere that the DC-3 was the most produced airplane ever (checking Wikipedia, that would have to include the C-47), but the 737 is getting close.
I can understand not thinking 50 years ahead when creating the 737. I remember reading about how the engine inlet of the -300/-400/-500 (now referred to as the 737 Classic) had to be slightly out-of-round to avoid sucking in debris. And in an age where airlines are trying to squeeze every bit of efficiency they can get I always wondered how much of a drag penalty there was for not having doors over the retracted main gear.
I hadn’t heard that the 787 needed any redesign for a stretch version, but that really does sound like a lack of foresight.
As the legs grow longer, how close are they to needing to redo terminal jetways so that all the little placers that don’t have 747 & 380 service for passenger handling of high doors? Not that many sockets with those even in big terminals so $$$$$ are going to be needed for many forms of retrofitting???
Or is really a non-problem for the foreseeable future?
Mostly a non-problem.
Jet bridges are adjustable across a standard range of heights. The 707 & DC8 cabin door sills were within a couple inches of each other and that set the original standard in the early-mid '60s. The 727 was the same height as the 707. The 737 is a foot or so shorter, but even the latest ones being built today are the same height the original baby 737-100 was.
The DC-9 and subsequent derivitives MD-80, MD-90, MD-95, & Boeing 717 are all ~2 feet shorter than 707 standard. So just a bit shorter than the 737. Those were within the adjustment range of the early jet bridges
The 747 came next and set the height standard for wide bodies which was considerably taller than the 707/DC-8. That forced the replacement of a bunch of jet bridges, mostly at the major international gateways. The cabin doors were wider too, so bridges & cabs got wider also. But this stuff was all changed back in the 1970s. Almost all the new taller bridges that were installed in response to the 747 have themselves been replaced simply through old age and failure. Or have been updated / upgraded.
A couple years after the 747 the DC-10 and L-1011 joined the fleet. Taller than the 707/DC-8, but shorter than the 747. So within the adjustment range.
Next came the 767 & 757 which share the same sill height and sat slightly lower than the L-1011/DC-10. So again within the then-standard adjustment range. At about the same timeframe the Airbus A300, A310 and later A330 & A340 came on the scene. At roughly the same height as the DC-10/L-1011.
So overall, from the very late 60s until the mid 90s not much has changed on the high or low end. There have been two developments in the last 20 years that have been putting pressure on infrastructure. The A380 lower deck sits a little higher than the 747 does. So for the comparatively few gates world wide that see A380s, the jetbridges need to go farther upwards.
By far the bigger issue numerically is the advent of RJs that sit real low. At many airports those are still boarded by walking across the ramp. At other airports the ordinary narrowbody jetways are knelt down as far as they go and a steep half-assed ramp is attached to the end to descend the last 4 feet down to the RJ door sill.
Terminals designed for RJs are also being built differently, with the boarding lounges at ground level and mini jetways that slope up the 3 to 5 feet to the door sill height. Rather than the 707 standard which has the passenger lounge on a tall second floor 25ish feet above ground level and a jetbridge sloping down to the aircraft door at 8-10 feet above ground level.
The 787 series sits above the old 707 but below the 757/767. So it’s not an issue.
Airports that don’t see the real tall 747 & A380 won’t have jetbridges to accommodate. If it’s an airline-served airport at all it probably has one set of very tall stairs for just-in-case use.
We have a list of approved diversion stations for each aircraft type. Bringing a jet into an airport that’s not equipped for the type can be the start of a multi-hour or -day nightmare for all involved. Do they have appropriate stairs, cargo unloading equipment, tugs and towbars, etc., etc.
The bigger and more exotic the aircraft, the shorter the list of acceptable divert airports. As an example, my carrier’s list of acceptable divert stations for the 757 is about 100 airports in the US. The 767’s list is only about 40, despite them being sorta twin sons of different mothers and very common aircraft in the industry for 3 decades now. The 737’s list is over 200 but the 787’s is just a couple dozen so far, albeit more all the time.
Our approach to emergencies is not “find the nearest concrete”. It’s “find the nearest acceptable concrete & services”. It’s only the really Hollywood-implausible scenarios that would persuade us to land on the nearest concrete with no other considerations.
