Are BOS-OAK JetBlue flights diverting to refuel?
 

I noticed that both of the BOS-OAK flights on Dec 31 had unexpected stops enroute--the morning flight in SLC, and the evening flight in DEN.

I remember reading some months ago that the JetBlue A320's barely had the fuel range for routes like BOS-OAK. I also noticed that the winds aloft on Dec 31 were very strongly out of the west. Putting two and two together, am I correct in assuming that JetBlue has to do enroute refueling stops on transcons whenever there are strong headwinds?

I've previously been a big fan of the airline, but this would seem to be a major drawback (!)

Looks like this morning's BOS-OAK is doing it again (stop in DEN)...

I hope they warn the passengers before boarding! I flew BOS-SFO recently nonstop (on another airline) specifically because I had a very bad cold and couldn't handle more than one cabin pressurization/depressurization event. (Actually I could barely handle that; I haven't been able to hear much since returning from that trip.) I'd be none too pleased to find out about an enroute stop after departing.

Yes, Possibly
 

The A320 has varying ranges depending on configuration, but let's start with the fact that BOS-OAK is at least 2345 nm. (That's with exceptionally favorable routing.) Airliners.net says that range is up to 3065 nm (with the V2500 engines, which is what JB's got) with an "economical cruising speed" of 454 knots at 37,000 feet. Ignoring the climb and descent times/burns for a moment, 3065 nm at 454 knots is almost exactly 6 3/4 hours of endurance (time aloft), which is really what you want to go by. (Airplanes don't really have ranges. They have endurance times. If the headwind exactly equals your forward airspeed, then your range is zero. :) )

Now let's add a headwind and do some back-of-the-envelope math with 2345 nm. Suppose there's an 90 knot headwind. That takes the forward ground speed down to 364 knots. And that would require just under 6 1/2 hours of endurance to fly BOS-OAK. You can do similar calculations for different headwinds.

Anyway, you get the picture. Basically, throw in a heavy-duty headwind (which happens in winter) and they could be having problems making the distance.

There's a version of the 737-700 that (according to the same web site) can do 3260 nm range. (Excluding the BBJ variants.) But that's the only one that'll go farther than the A320 on full tanks. And there's a non-corporate A319 variant (common type rating with A320) that'll go farther than a 737-700, so you could play that game forever.

By the way, to see what the "real" computer says, for a little more back-of-the-envelope precision, I just went to DUATS and ran the numbers. (DUATS is the FAA's flight plan filing system.) For you geeks in the house I let DUATS pick the regular jet airway routing using extremely favorable (and therefore unlikely :) ) BOS and OAK VOR transitions to the jet airways (since I have no clue what you'd really get). That's the 2345 nm distance, which is almost certainly the shortest clearance you could hope for. Then I assumed 2000 foot/minute rates of climb and descent, 250 knots forward speed for both, and 37000 foot cruise at 454 knots. (Those assumptions are probably "close enough" for these purposes. I'm not sure 37K is the appropriate altitude, though, but I'm assuming everything in the aircraft's favor here.) I picked today (January 2, 2005) with a departure time of 1700 UTC. And guess what? DUATS says that trip, with prevailing and forecast winds, ought to take 6 hours and 33 minutes. Headwinds at that altitude over that route are expected to hit a peak average of 116 knots straight out of the west between the Badger VOR (near Milwaukee) and MCW (Mason City, Iowa) -- which is not helpful. :D

So you can see how JetBlue might have trouble over that route right now. That's a stiff headwind, although it does happen in the winter. (I had a ~70 knot headwind at 4,000 feet once. Near the Badger VOR, as it happens.) If you're the pilot looking at around 12 minutes before you start to dip into minimum legally required reserve fuel, do you really want to take your chances that everything is going to go perfectly, including the shortest possible route clearance and zero air traffic control delays? A fuel stop is prudent in these circumstances.

Sipples (who seems to have quiet a bit of aviation knowledge) gave a good explanation to the persistent transcontinental range problem JetBlue has with their A320. Once again this week the BOS-LAX flights have had technical stops due to the A320s endurance problems.

According to pilots I've spoken with the A320 is- under ideal conditions- a seven hour airplane plus minimum reserves. Problems crop up when there is a screaming wet-to-east jet stream, a destination airport like SFO or LAX is IFR and they have to file an alternate adding additional fuel loads. Additionally the A320 near take-off gross weight has to initial at a lower westbound altitude than the equivalent Boeing 737-800, burning more fuel per hour for the beginning of the flight. Technical aviation journals I've read indicate the airline has pleaded with Airbus for years to find ways to increase the aircraft's range.

I love JetBlue but I had my first refueling adventure with them this week. Most people took it in stride but it is a little frustrating to know that American and United with their larger and longer ranged Boeing 757s never suffer this problem.

Welcome to flyertalk
 

Welcome to Flyertalk , Globetripper.

What's "has to initial" mean?

Thanks for the info!

Although a flight may "cruise at 36,000 feet," it typically will not take off and immediately proceed to that altitude. A JFK-LAX flight, for example, may file for a cruise at 36,000 feet, but may take off from JFK and top out at 32,000 feet until, say, Kentucky. From there, it may climb to 34,000 feet until, for example, Oklahoma. At that point, enough fuel has been burned to make cruising at 36,000 feet efficient. If a fully loaded A320 took off from JFK and proceeded directly to 36,000 feet, it would not be operating as efficiently as possible because of its initial weight. The actual flight plan and climb profile will vary depending on the weather factors involved.

A fully loaded 737-800, by contrast, is able to climb to those more efficient fuel burning higher altitudes quicker than a fully loaded A320.

I hope that's helpful... I'm clearly not the best person to explain something in a non-confusing way. ;-)

ETA: As an example, check out the profile for JBU671 JFK-LAX on February 10. As you can see, the flight climbed to 32,000 feet and remained there for ~40 minutes. From there, it climbed to 34,000 feet for another 90 minutes. After that, it climbed to 36,000 feet for the remainder of the flight. GloberTripper means that the 737-800 is, generally, able to get to that 36,000 cruise quicker than the A320, and thus operate a bit more efficiently.

That makes sense caphis. Now I remember what we're talking about.

There is a reason VX uses the A319 on BOS-SFO...

This happens to some JetBlue flights from BOS or (less commonly) JFK to SFO / OAK or (less commonly) LAX / LGB / SAN. It's often due to headwinds which tend to blow towards the East, making the flight from BOS to SFO usually longer than a SFO to BOS (where you are likely to see a tailwind)

Funny enough, this *just* happened on a friend's BOS-SFO flight yesterday. They had to stop at DEN for a refuel.

-Rob

BOS-SFO is no longer a non-stop then

My sister was on Wednesday's flight and they got the NASCAR treatment at SLC. Ended up barely an hour late which was better than expected. They were notified before they left BOS that there was going to be a stop. Everyone got a $25 credit

Seems really inconsiderate to fly with your "very bad cold."

Remember how you would not have liked the surprise of an unplanned fuel stop en route? Think of how your seat opponents would like the surprise of a nasty cold as a souvenir of their flight.

Same problem with Alaska's flights to SEA from Florida (MIA/Orlando) -- sometimes have to refuel in Oklahoma or somewhere nearby, due to headwinds in the winter.