g500 From United States of America, joined Oct 2011, 724 posts, RR: 0 Posted (4 months 1 week 21 hours ago) and read 2329 times:
During the winter season when the head-winds are particularly strong flying from say N.Y to California can get tight in a A319/320 and 737-700 due to strong headwinds... I remember JetBlue, Virgin and AirTran had a bunch of diversions a couple of years ago on flights from the East to the West Coast, due to "stronger than predicted winds" .. Even Alaska had to stop a couple of times.
How strong does the head-wind need to be to force a diversion on a narrow-body flying from East to West? I'm guessing over 100 knots on the nose?
I've heard airlines divert into SLC a few times. Looks like SLC is a favorite spot to stop for fuel. As a passenger i'd rather stop there than LAS or PHX
jetmatt777 From United States of America, joined Jun 2005, 2662 posts, RR: 36 Reply 1, posted (4 months 1 week 17 hours ago) and read 2057 times:
Quoting g500 (Thread starter): I've heard airlines divert into SLC a few times. Looks like SLC is a favorite spot to stop for fuel. As a passenger i'd rather stop there than LAS or PHX
Why does it matter? Gas 'n' go's do not take very long, especially for narrowbodies.
Quoting g500 (Thread starter): How strong does the head-wind need to be to force a diversion on a narrow-body flying from East to West? I'm guessing over 100 knots on the nose?
Roseflyer From United States of America, joined Feb 2004, 8742 posts, RR: 52 Reply 2, posted (4 months 1 week 2 hours ago) and read 1877 times:
There are a lot of factors involved. If an airplane is not filled to capacity, then the need for a fuel stop goes away. Some airlines are willing to block seats to allow more payload available for fuel (assuming tanks aren’t full). Other airlines prefer a fuel stop and filling all the seats instead of bumping passengers.
As the previous poster pointed out, winds aren’t continuous. Airplane dispatchers will dispatch creative routes where the airplane will cover more ground distance to avoid the winds. A 737NG can fly over 7 hours with full tanks, but they would exceed MTOW to fill the tanks up with a full load of passengers, baggage and cargo along with fuel for an alternate. Flights into SFO see more diversions than LAX because of the need for fuel to cover an alternate (even though OAK and SJC are close alternates) because the weather is so often bad.
In 2003 the FAA increased passenger weights after the Air Midwest crash in Charlotte which caused a lot more fuel diversions and essentially ended AS operating 737-900s on transcon routes because there was less payload available for fuel.
If you have never designed an airplane part before, let the real designers do the work!
Starlionblue From Hong Kong, joined Feb 2004, 15870 posts, RR: 66 Reply 4, posted (4 months 6 days 22 hours ago) and read 1793 times:
Quoting thegeek (Reply 3): Is the high elevation of the field a factor with this? Saves time in descent and climb.
High altitude means worse take-off performance, and I think that would have a bigger effect than the small time saving. SLC is at 4227 feet. Compared to sea level that's 2 minutes extra climb time.
Fuel is king. If fuel is cheaper at SLC, even by a little, that's the place to go. Not to mention routing.
[Edited 2013-01-15 19:43:53]
"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo
B6JFKH81 From United States of America, joined Mar 2006, 2767 posts, RR: 7 Reply 5, posted (4 months 6 days 4 hours ago) and read 1652 times:
Quoting g500 (Thread starter): I've heard airlines divert into SLC a few times. Looks like SLC is a favorite spot to stop for fuel. As a passenger i'd rather stop there than LAS or PHX
It's not really a diversion....it's a scheduled fuel stop or "tech stop", which is scheduled before the aircraft even departs normally (based on my knowledge). I have been on a few flights that went into SLC (and were briefed by the captain that was going to be the case before departing JFK), we were back in the air within 30 minutes of touching down. You do not get out of the plane. You go to a hard stand, fuel up, go to the de-ice pad, get sprayed, and leave. There could be multiple factors, but I'm sure the price of fuel is a big one when you have to stop to take on more fuel just to complete the flight so cheaper is better at that point.
"If you do not learn from history, you are doomed to repeat it"
DFWHeavy From United States of America, joined Jul 2011, 469 posts, RR: 0 Reply 6, posted (4 months 6 days 2 hours ago) and read 1627 times:
Also, the 737-700 wouldn't have any issues, any time of year. It's the 737-800/900 that run into issues once in a blue moon....along with baby buses of course.
B747forever From United States of America, joined May 2007, 16574 posts, RR: 11 Reply 7, posted (4 months 5 days 18 hours ago) and read 1544 times:
Quoting DFWHeavy (Reply 6): Also, the 737-700 wouldn't have any issues, any time of year. It's the 737-800/900 that run into issues once in a blue moon....along with baby buses of course.
Exactly. Doesnt both the 737-700 and A319 have longer range capabilities than their larger siblings?
glen From Switzerland, joined Jun 2005, 199 posts, RR: 2 Reply 8, posted (4 months 5 days 14 hours ago) and read 1515 times:
Quoting B747forever (Reply 7): Exactly. Doesnt both the 737-700 and A319 have longer range capabilities than their larger siblings?
For the same amount of fuel the range of the A319 is considerably better than on the A320 or A321, due to its lower weight.
Things look different if you want to transport the same high payload, for example the max possible load on a A319 (rounded figures):
DOW: 42t, MZFW: 58.5t, MTOW: 68t ; so you have a maximum payload of 16.5t and are then able to take 9.5t of fuel which gives a range of approx. 1750 NM without reserves.
A320:
DOW: 43.5t, MZFW: 61t, MTOW 73.5t ; so with the same payload of 16.5 t you are at a ZFW of 60t and 1t below MZFW and are able to take 13.5t of fuel - 4t more than the A319 and a range of approx. 2100 NM without reserves.
A321:
DOW 49t, MZFW: 71t, MTOW 83t ; so with the same payload of 16.5t you are at a ZFW of 65.5t and 5.5t below MZFW and are able to take 17.5t of fuel - 8t more than the A319 and considerable more than required to compensate the higher fuel burn of the A321, i.e. a range of approx. 2600 NM without reserves.
So for the same payload the A321 has longest range capability amongst the three, or is able to carry more payload for a given distance.
"The horizon of many people is a circle with zero radius which they call their point of view." - Albert Einstein
Roseflyer From United States of America, joined Feb 2004, 8742 posts, RR: 52 Reply 9, posted (4 months 5 days 1 hour ago) and read 1380 times:
Quoting glen (Reply 8): So for the same payload the A321 has longest range capability amongst the three, or is able to carry more payload for a given distance.
That is true, but no airline operates its airplanes like that. The A321 would be loaded up with more passengers, baggage and cargo. So while at the same payload it has more range, when at a normal operational payload it has less range.
If you have never designed an airplane part before, let the real designers do the work!
glen From Switzerland, joined Jun 2005, 199 posts, RR: 2 Reply 10, posted (4 months 4 days 17 hours ago) and read 1301 times:
Quoting Roseflyer (Reply 9): That is true, but no airline operates its airplanes like that. The A321 would be loaded up with more passengers, baggage and cargo. So while at the same payload it has more range, when at a normal operational payload it has less range.
Sorry, my text was not very clear in this point - all I wanted to show was that not the A319 has best range when loaded.
May be I should have better left the comparison between the A319 and A320 at max payload, where the A320 is definitely best.
However even loaded up to MZFW, gives the A321 the possibility to load 12 t of fuel, which gives a range of little bit more than 1700 NM without reserves - not far off the A319. The A319 has only good range capabilities if there's not much payload, leaving room for more fuel - profitability would be the other question then...
"The horizon of many people is a circle with zero radius which they call their point of view." - Albert Einstein
However even loaded up to MZFW, gives the A321 the possibility to load 12 t of fuel, which gives a range of little bit more than 1700 NM without reserves - not far off the A319. The A319 has only good range capabilities if there's not much payload, leaving room for more fuel - profitability would be the other question then...
True, although rarely are A320s or 737NGs loaded up to MZFW. You see that more often on regional jets where landing weight becomes a factor and on their short segments.
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