Catbert10

I've been flying this route for more years than I'd like to remember, so I'm pretty familiar with with flight profile. Used to be, the flight rapidly went to ~21K, leveled off for a few minutes, then started a gradual descent/glide into AUS. Since February, it seems like most flights (not all) are only going to between 12K and 14K. Flights from AUS-IAH seem to be rise to ~20K. Other than giving a legitimate reason for not serving drinks in FC, why would UA do this? Not rising above the weather is uncomfortable, and spending 30m in a paint shaker isn't desirable.

mahasamatman

Most likely because is uses less fuel, and fits better into ATC's plans. I suspect the winds may be more favorable as well.

danielSuper

Probably Jet-stream.
14k jet-stream speed ~20 knots https://www.ventusky.com/?p=30.3;-94.4;5&l=wind-600hpa
20k+ jet-stream speed ~90 knots https://www.ventusky.com/?p=30.3;-94.4;5&l=wind-300hpa

sbm12

Might be time to put the foil hat away.

physioprof

Does United have much say in the matter? Doesn't ATC tell them where to fly?

pinerd

I flew recently from DFW to SFO and the pilot made a point to say there was lots of turbulence above 28-30K so we flew the entire way at 28K.

skylane

In heavily trafficked routes, yes, ATC will dictate the route and altitude (standard terminal arrivals and departures for example). Typically the pilot files a route/altitude and then ATC will either grant it or provide an alternate clearance.

Looking at FlightAware

https://flightaware.com/live/flight/...310Z/KIAH/KAUS

The assigned route was BNDTO5 MNURE WLEEE4. The BNDTO5 MNURE has a standard altitude of 16000.

https://flightaware.com/resources/ai...DTO+FIVE+(RNAV)

Yes, when flying from IAH to AUS, you go through MNURE.

mduell

OAPM may have played a role in changing what you're flying now compared to what you flew 5-10 years ago.

Mike Jacoubowsky

Got you beat... COS-DEN. 11,900ft max altitude. Which means only 6000ft above the ground. https://flightaware.com/live/flight/.../KDEN/tracklog

Wish I'd kept the printout from my OAK-SFO flight some years back. Sadly, we didn't get the "skim the bay" but took a normal take-off & landing approach, making a U-turn over San Jose. Probably about 4000ft. At 3am, they probably could have sent us across the bay... :-)

chermorg

I've always had at least one drink round in F between IAH-AUS (and vice versa) that I can remember. Even when the flight time is <30 minutes. That sounds more like a crew issue you've experienced and nothing to do with the altitude, which as others have said, depends on winds and ATC routing.

Hammer0425

There is recently a totally new departure and arrival procedure for Houston from all directions. The arrivals in particular are almost all “descend via” (versus being stepped down) and the departures are often “climb via” with various crossing restrictions that may or may not be required that day. As a result, you’ll find much less randomness on your altitude and routing if you’re coming from or departing to the same direction frequently. Flights like Austin or San Antonio, a IAH departure may end well past that airport so even if you’re just flying a departure into a transition and if the altitude along that route is published, you’re probably never going to get above it. Absolutely could be the reason you’re noticing a lower altitude en route now. Has to do with traffic efficiency and the ATC SID (departure) or STAR (arrival) 19 times out of 20 (and never the flight attendants trying to get out of doing a drink service).

trooper

Not what I expected when I read the thread title! LOL (I was thinking...LOW!)

jiaogulan

Reminds me of KUL-SIN.

mozilla

To add to this, in the case of the major airline it's a computer/dispatcher that files the flight plan, and generally, the most favorable cruising altitude economy-wise would be filed (depending on restrictions). Of course the pilots have discretion and can request another altitude, but otherwise, ATC would generally assign the filed altitude if other traffic or circumstances don't get it in the way. Based on the FlightAware data it looked like a request for lower cruising altitudes was filed by UA's dispatch.

I believe FlightAware shows the filed route rather than the assigned route. In any case, this procedure hasn't been changed since 2015 so in itself wouldn't be cause for any recent change. ATC is free to deviate and assign higher altitudes, traffic and other restrictions permitting.

WX could certainly be a factor. FAA is also trialing noise reductions with slower departures which results in slower climbs and for a very short flight would result in a lower cruise altitude (there's a story about Boston, WSJ paywall).

RunningforMiles

This is a traffic flow management technique called capping. In congested areas it can allow for aircraft flying to nearby destinations to remain in the terminal or low sector en route environments which can ease congestion in the higher altitude center sectors. If this is something that the Houston Center traffic management unit wants to do, then they may issue a reroute advisory (unless these are LOA’d or preferred routes already which they probably are) and then clear aircraft via this route. This may be different then what the flights dispatcher filed, although they are well aware of these types of routes, and the pilots would be read the new clearance when they first make contact with ATC at the departure airport.