Only from those who know what it takes (either through pilot experience or at least being around "the biz" enough). I vividly remember one landing at IAD several years ago where we were crabbing at some crazy angle coming in on final. The pilot expertly lined us up and the touchdown was smooth as glass. I was impressed as hell, but the woman next to me was verbally complaining about how she'd "never experienced such a crooked landing before". I tried to explain but could tell she wasn't listening or understanding. I did make sure to poke my head in the cockpit on my way out to share my kudos for a perfectly-executed, challenging crosswind landing. I think the pilots appreciated hearing it (at least I hope they like getting compliments from the cattle in the back!).

A dumb question perhaps, but something I have noticed on most of my mainline flights from EWR-PBI/FLL/MIA is that the plane usually hugs the coast pretty tightly, even though I believe the vast majority of UA's narrowbody fleet is ETOPS-certified. Based on the GCM routing, I would expect the planes to fly substantially further offshore. Why does this not usually happen?

depends how much the military opens airspace. We see this often/in the past during holiday periods where additional air space is opened up along the east coast/seaboard.

The entire 737 fleet is ETOPS. The A319 and A320 fleets are not. The A321 will be ETOPS but I don't know if they are today.

ETOPS doesn't matter for your question, though, as ETOPS is not requires for the east coast to southern Florida routes. It isn't even required for the EWR to the Caribbean routes unless Bermuda is unavailable.

The offshore routes can be closed for military activity, weather, or launches from the Kennedy Space Center.

I have questions about takeoff flap protocol. What's I've noticed:

Most common protocol:
Pushback --> engine start --> flaps deployed --> begin taxi (yes... lots of other things going on during all that, too)

Variations I've experienced:
Skywest E175 standard procedure: Pushback --> flaps deployed right when pushback begins --> engine start --> begin taxi
For deicing: Pushback --> deicing --> engine start --> begin taxi --> flaps deployed during taxi

I also had one experience at O'Hare when we were in a very long takeoff line. Second engine wasn't started and flaps weren't deployed until we got closer to the front of the line.

Can someone provide any additional commentary or explanation as to why there are variations from the most common scenario? My heart rate goes up when we're taxiing and the flaps haven't been deployed yet. Please tell me there is a system in place to prevent takeoff without flaps deployed and I don't need to get so nervous when the procedure is different than the norm!

Very astute of you but all normal operations, no need to fret.

After de-icing, especially when taxiing on a “contaminated” taxiway - (one with snow/ice actively on it) we don’t put the flaps down until closer to the takeoff runway. Goal is to prevent snow and ice from building underneath and possibly between the flap/wing surfaces.

Other scenario is referred to as a delayed engine start. Non-wide body aircraft utilize this just to reduce fuel consumption while waiting to depart. There’s a checklist performed after the delayed engine start to re-configure aircraft bleeds (air conditioning), flap configuration, etc. prior to takeoff.

Additionally, prior to takeoff there is a takeoff configuration button we push which sets off a loud horn if the flaps or brakes are in the improper setting. It’s been a long time since I’ve been on the 737, I believe that was part of the Captain’s flow just prior to takeoff.

Hope this helps.

Another reason for a late flap change is when we get new takeoff performance due to changing conditions. In the 737, we might be setup for a Flaps 1 takeoff but the wind gusts pickup so we change to a Flaps 5 takeoff the produce a more positive liftoff.

And Club's right about the takeoff config check being on the Captain's flow.

Pardon my ignorance here but what are the tradeoffs between "Flaps 1" and "Flaps 5"? In other words if Flaps 5 creates a more positive takeoff why isn't that the standard -- does it have downsides for fuel consumption, ride quality, ...?

But new question: Coming into Denver today on a Max 9 this morning it was a fairly bumpy (more jolt-y) ride even by DEN standards -- but in addition to the chop and sway I'm used to there was a pronounced up and down feeling I can't remember noticing before (like we were following the curve on a sinewave or riding the back of a porpoise or dolphin) -- not to a huge degree, but enough to be perceptible) what is kind of atmospheric condition that leads to that kind of ride?

A 737 is approved for takeoff in the Flaps 1, Flaps 5, Flaps 10, Flaps 15, or Flaps 25 configuration.

Lower flap settings require longer runways but produce a faster after-takeoff (second-segment) climb. Higher flap settings do the opposite but may be required on shorter runways, at the expense of the second-segment climb. That's why a short runway, in mountainous terrain, produces the largest weight restrictions. It's also why DEN has a 16,000' runway.

Given a long enough runway, Flaps 1 is the default setting. As the runway gets shorter, we move to setting with more flaps. During a Flaps 1 takeoff, the aircraft will roll on the runway longer after rotation (doing a wheelie) before the main gear become airborne. When we have gusty crosswinds we're prefer a more positive liftoff at rotation so use Flaps 5 as a minimum. The computer which generates the takeoff data doesn't know that so it's a crew decision.

Turbulence is caused by moving air. The aircraft will react differently depending on how the air is moving, in which directions, and how abruptly the speed and direction changes.

I would always defer to Larry and the other pilots here but my guess is that you experienced what I believe is called Mountain Wave. Sometimes it is really pronounced over the Rockies. Much less-so over the Sierras.

Lurker :)

Thank you, as always for the great insight! And funny you should mention that one as on the departure we were parked waiting for (I believe) that runway to become available: We are a fully loaded (at least PAX wise) 737-900 and the captain made the PA that due to our weight, the temperature, and the winds we'd have to wait for the one runway that could accommodate the performance we needed for departure (originally estimated as a 30-40 minute wait, shortened to about 15) so we were also going to add fuel to avoid having to remove anyone or anything. (Based on his PAs, a gift stroopwafel on boarding, and a very delicate handling of a potentially inebriated passenger I like this guy :) )

Based on the diagram that's exactly what my body perceived we were doing. As I was staring down at the relatively flat land its easy to forget how far out the mountains can influence weather (the linked diagram representing ~125-310 miles for those who speak Metric less than fluently)

Who calculate all of the aircraft numbers (e.g. curb weight) for a particular flight?

Was on a flight today, inbound arrived early, we pushed timely, but then sat for more than 30 minutes prior to takeoff.

Arrived at gate even later. Connecting flight pushed around the same time. I am annoyed.

Are these numbers not ran prior to pushback?

It is an ongoing process which starts several hours before departure time.

Passenger count, baggage weight, and cargo weight are all being updated throughout the process. A couple of prior to departure, the dispatcher plans the flight and fuel load, all based on the payload estimates at that time. The fuel load request is sent to the fueling provider inside an hour from departure.

As bags and cargo are loaded, they are scanned on which electronically adds their weight to the ongoing total. Same with each passenger who is boarded. When boarding is complete, the agent finalizes the seat map (passenger count). A ramp supervisor does the same when bag and cargo loading is complete. At that point, a load planner in Chicago checks the plan to ensure that all limitations are met. He then releases the final weights to the crew via ACARS. We uplink the final weight and CG location into the FMS and compare the values to our performance and structural limits.

We receive the final weights before pushback less than half the time. The rest of the time it arrives at some point during or after pushback. Rarely, there will be an issue that much be worked out which delays the final weights. Usually, they arrive in plenty of time so that they do not delay our takeoff.

Thanks Larry for the detailed walkthrough! Second delay in such nature the last four months - probably my luck. Usually I am O&D, so not a huge deal, but I was connecting and required an involuntary overnight.

Watching every plane behind you takeoff adds to the frustration.

from same departure point?

Typically, the reason for a delay after pushback is either the ramp is forwarding bags that are not checked in for that particular flight, or there was a number of pax who missed a prior flight and the departing airport didn't notify the load planner that there are going to be additional passengers on the flight that was not planned for hours before.