No disagreement there.

I'm fascinated that UA has what seems to be like 20-30 a/c out of service for MX at any given time, along with Jeff's stern words that they're working on operational reliability. Do AA and DL have that many birds down at one time?

Each regional is responsible for its MX. For instance, SkyWest has an MX hangar at SBN.

My question is: When there is an IRROP, who decides where a UX plane will be/go: United or the Regional?

The regional. United sets the schedule, and can adjust the schedule according to its needs, or the needs of regional (MX scheduling, etc.,) but United cannot interfere with the actual operation of the airline.

OP notes that he was on a 737-900, which has a comparatively high landing speed due, in part, to the length of the fuselage and desire to avoid tailstrikes. With a higher Vref (basically, the speed at which the a/c crosses the threshold), the deck angle flattens out and reduces the likelihood of scraping the tail. I've flown on 739 flights that came in with a ref of ~170kts... that's pretty fast.

My understanding, admittedly having never flown the 739, is that it is a more demanding aircraft from a pilot's perspective than, say, a 757-200. Certainly well within the capability of professional pilots, though, and within the normal operating envelope for the airplane, so no explanation for mx issues.

Are there options in terms of pilot controls and avionics that a carrier can choose to/not to get?

I wonder because we see CO buying these planes stripped (no TVs, no Internet, etc.), while some carriers buy the very same plane loaded (e.g., AA, DL).

Is it like a car where there are control options as well, and maybe there's something they're not buying that could make it easier to fly?

As a passenger, I guess I find it very hard to judge speed from the back of the plane. Sometimes it feels like the pilots land some of the planes very slowly with full flaps extended. I feel like back in the old PMUA days, this was how they all landed. Then again, other times they don't bother. Still, I would have a hard time judging what was too fast.

What I do find I can mentally construct when landing at a familiar airport is the glideslope. I find this is especially easy at airports like SFO with the bridge approach from the south. Every once in a while, I'll note that we're too high by the Dumbarton or San Mateo bridge, and indeed the sink rate notably increases. I'm not sure if this is the controller's doing or the pilot's choice. Usually when listening to Channel 9, the ATC instruction is something like cross the bridge at or above X,0000 feet.

Interested to know more from one of our resident pilots.

Not really. The high landing speed is aerodynamic in nature and is a function of the length of the fuselage, height of the landing gear, wing design, tail clearance, etc. The Vref calculation takes into account, among other things, aircraft weight, flap setting, winds and gust factor. The airplane can land at a slower speed, but with a steeper pitch attitude comes greater risk of a tailstrike and the possibility of bending the airplane. Nobody wants that.

In terms of equipment CO/UA elected not to equip their 737s with, the only thing I can think of immediately is a HUD, which is standard on the 787. However, this device has no impact on aerodynamics or performance and is really most useful in cases of reduced visibility approaches.

Generally speaking, aircraft like the 757-200, A320, 777-200, 747-400 etc. have slower landing speeds than a 737-900, 767-400, 757-300, etc.

Just a couple of months ago arriving at IAH from SAN on a bright sunny day, the 739 landed with a hard jolt! The FA in his "welcome to Houston" announcement began with "Now after that great landing....", upon which a number of passengers laughed out loud or chuckeld!

Normally the plane kind of floats above the runway for a second and then there's a gentle touch down when a pilot is at the controls. There are times due to conditions that it's rougher than normal. Is there a difference when the autopilot lands the aircraft? You hear people say "Oh, well, the auto land is a rougher landing." But is that actually the case?

A friend who was a pilot for CO and now UA stated to me one time a few years ago that if it's completely overcast/can't see the ground at X,000 feet it was company policy at the time to auto land. It was completely overcast, so was it just a rough auto land? It just didn't seem to have the finesse of a professional pilot. I don't even know if that's still a policy or even how accurate that statement was at the time.

Remember too that your speed over the ground is different from your speed through the air. Two planes could land with the exact same airspeed, but one could appear faster because of less headwind, or even a slight tailwind.

I've had a small string as well. 2 weeks ago IAH to Denver. Got new plane but missed connection. Was offered miles as compensation before we even landed.

Last week AUS to Denver on RJ couldn't start engine. Missed connection in Denver again no compensation offered.

First time easy to find hotel room. Last week Denver was hellish. Luckily found delay flight to PDX ( trying to get to GEG) where there were some hotel rooms.

I always thought that the 739 & 738 landed fast too. I generally chalked it up to what I thought was an FAA order after that USAir 737 flipped over and dug a hole in PA some time ago coupled with the fact that the 738/739 are crappy old designs never originally intended to be that long still with landgear way to short for the plane. When riding in F I always find it amusing to hear the nosegear sound like it is going to spin right off the plane. Hate the 738/739's

I just jumpseated on a UA 737-900 this morning. I didn't ask the guys what typical landing weights are, nor what we weighed at landing, but the Vref was 145, and the target speed was 150, all in knots. The landing was in DEN which at 5,430' and 70 degrees F puts the density altitude at about 7,600�, lot higher than a sea-level airport, so the groundspeed was probably around 170 knots, or 195 MPH. That's about 30% faster than the same landing at SFO.

A 757-200 at a typical landing weight will have a Vref of about 125 knots and a target speed of 130. Comparing a 737-900 to a 757-200, the 737 is about 15% faster at touchdown, and the 757 has twice as many main wheels, thus about double the wheel braking. Short runways, no thank you.

These guys had not flown the 737 with the Split Scimitar winglets yet, but they weren�t too enthused about it. They said that the book procedure for landing in anything over a 15 knot crosswind is to land in a crab, where the longitudinal axis of the plane is not parallel to the runway centerline. The main gear on all 737s is slightly castering, which is to allow a crabbed landing without yanking the main gear out of their mounts. I don�t know the dimensions of the 737s, but suffice it to say that you can�t land too wing-low without scraping some pretty expensive aluminum.


Autolands are a very specialized thing. Different airlines have different operations specifications (OpsSpecs) as to how they get airplanes on the ground in very low visibility. Some of the criteria are crew training and certification, aircraft auto land capabilities, and different instrumentation. SWA, for example, uses Heads Up Displays and manually flown landings, while UA, at least the sUAL side has all auto land certified aircraft and crews.

there are lots more factors here, but basically, sUAL crews can land in zero visibility, something that can�t be done (legally) in a non-autoland certified plane. UA went the auto land route long ago so we could complete more flights in nasty weather.

That said, the autoland system, which is only a part of the whole autoflight system, will pretty consistently do a landing that�s a 5, 6 or 7 on the �10� scale. It�ll never do one better than a very lucky, skilled, intrepid aviator can do, unless it�s malfunctioning or it�s done in out-of-limit weather conditions. I can usually beat the autopilot, and on those days that I don�t, I send my F/O out to say goodbye to the passengers

Something a lot of folks don�t know is that it�s a LOT more work in setup, monitoring, and execution to do an autoland, or any low-visibility approach and landing, for that matter, than a hand-flown landing. Way more things that can go wrong. I do them in the simulator for recertification on every Proficiency Check, and maybe two or three a year besides that.

And there are no auto takeoffs, none, zero, zip, in commercial aviation. The takeoff is one of the most critical maneuvers that we do, potentially way more intense than any landing.

I had a few spare minutes on my hands

FAB

Glad you had the spare time, FAB.

I always love it when you chime in and post.

^

So, if there are delays, the regional makes adjustments - usually making passengers connecting to/from mainline flights miss connections.

Which airline pays for the missed connections, re-bookings, vouchers (yeah, right?!?)?