Simple question. Flying from Hawaii to the mainland, or West to East, will one typically have tailwinds or headwinds? What percentage of the time is this true? Is there a resource that I can reference to show a particularly stubborn person who swears that you will always have headwinds going back to the mainland? I've shown him the upper level winds chart, which he swore showed winds out of the East. I showed him how to read wind barbs, and he said that the information was wrong then. I told him that I flew this route routinely for ten years as a Navy Over Water International ETOPS instructor/elevator/standardization pilot (equivalent of check airman) on the C-40/737, and that 99% of the time I'd say the prevailing westerlies mean headwinds going west, and tailwinds going east. He's still adamant that I'm wrong because he always had easterly trade winds going from Oahu to Maui in Cessnas, and because one time a United Jet returned to Hawaii because of easterly winds. I know the trade winds are a factor down there, and at the lower altitudes he flew at, but crossing the pond, it's almost always the Westerlies. Help a brother out. My bro thinks 2+2 is 5, and there's no convincing him otherwise. Thanks.

You are correct on all counts, generally winds will be westerly (from the west) between Honolulu and the Mainland.

Just anecdotally, I can say that when I was routinely flying as a passenger between DFW and HNL, the westbound always took longer than the eastbound, by somewhere between 30 and 60 minutes depending on time of year as I recall. The other part of the journey was between HNL and AWK, and on that leg, the westbound was always a bit shorter than the eastbound, again by between 30 minutes to an hour because there you're flying in the trades pretty much the whole distance (and surface winds at both HNL and AWK usually favor RWY 8 at HNL and 10 at AWK)

Mcluvin wrote:

...and there's no convincing him otherwise.

I don't know what else you could do. In his defense, what those wind barbs are trying to say is not always self-evidently obvious to everyone. I even think Google's search results for wind direction may still be backwards from conventional notation.

Buzzcut nailed it.

Bring up actual flight times on Flightaware for opposing routes between the same city pairs.

Same day, same distance with different enroute times = wind.

Every flight i've done LAS/LAX-HNL has had a headwind flying west, tailwind flying East, as ever though, mother nature is a fickle thing so I am sure there are times at various levels that the opposite is true.

Coriolis Force. Prevailing winds in the Northern Hemisphere tend to deflect West to East and in the Southern Hemisphere deflect East to West. The closer to the equator you go the less affect of the winds. Now obviously there are things like Jetstreams that come and go, and are especially strong in the winter time when the troposphere is a lot lower, but generally that is the direction of the winds aloft. That's why TATL is always quicker going Eastbound then Westbound. I would assume same goes for Hawaii-Mainland.

I flew YYZ-HEL-YYZ last year on Finnair, the Eastbound leg was 7H10M flying time, Westbound was 9H05m, strong East-flowing jetstreams really slowed us down. It's also the same reason you see the Northeast US and Canadian Maritimes get hammered with huge winter storms. Weather builds over the Rockies and Coriolis Force pushes it East where it builds over the plains and then dumps 3 feet of snow on the Northeast.

ryan78 wrote:

Coriolis Force. Prevailing winds in the Northern Hemisphere tend to deflect West to East and in the Southern Hemisphere deflect East to West. The closer to the equator you go the less affect of the winds. Now obviously there are things like Jetstreams that come and go, and are especially strong in the winter time when the troposphere is a lot lower, but generally that is the direction of the winds aloft. That's why TATL is always quicker going Eastbound then Westbound. I would assume same goes for Hawaii-Mainland.

I flew YYZ-HEL-YYZ last year on Finnair, the Eastbound leg was 7H10M flying time, Westbound was 9H05m, strong East-flowing jetstreams really slowed us down. It's also the same reason you see the Northeast US and Canadian Maritimes get hammered with huge winter storms. Weather builds over the Rockies and Coriolis Force pushes it East where it builds over the plains and then dumps 3 feet of snow on the Northeast.

I'm sorry but your explanation doesn't fit with reality - I live in the Southern Hemisphere, and we definitely have prevailing westerlies at altitude in this neck of the woods. Check out: https://earth.nullschool.net/#current/w ... ectangular

Coriolis force affects the direction high and low pressure systems rotate (in the Southern Hemisphere high pressure systems or anticyclones rotate anticlockwise, in the Northern Hemisphere they rotate clockwise, and the opposite for low pressure systems or cyclones), but to say it tends to deflect winds "east to west" is a bit of an oversimplification. My understanding is that prevailing winds at altitude are primaily a function of the overall distribution of high and low pressure systems, which are actually predictable, and that in the equatorial region they tend to be easterly, while as you move towards mid lattitudes (which is where most of the flight path from Hawaii to North America would be) they tend to be westerly.

Actually that site I've linked may be useful for helping you friend visualise wind Mcluvin.

V/F

While most of the time, the winds are from West to East, it's not always the case. When we experience Santa Ana winds in Southern California, the cause is a high pressure area generally centered in Nevada, southern Utah, or Northern Arizona. This results in Easterly winds on at least part of the track to Hawaii. In addition to that, several times during winter months, the Jet Stream will run from North to South often bringing storms to the west coast from Alaska. During this type of condition, flights heading to Hawaii from the Mainland will experience a tailwind component!

Generally 30-60 minute differential with the HNL->SFO (or LAX or whatever) leg being shorter.

As someone who's done JFK-HNL roundtrip twice, I can confidently say that the prevailing wind is westerly in December/January. The
JFK-HNL leg was 10:35 the first time and 10:58 the second time. HNL-JFK legs were 9:20 and 9:42. The added time on the second trip was likely at least partly due to the fact that HA instituted a cost index program that dialed their A332's back from .82 to .80 in the cruise. If I can dig up some pics of the headwinds on the air show I'll post them. Looking at tonight's HA50 HNL-JFK, it's scheduled for ~9:10

Perhaps he might need to read the book of common sense ;-p

Starlionblue wrote:

For the more geeky among you, which side do the wind strength indicators on the barb face? Yes there is a rule for this.

On the side towards to the low pressure system.

The Prevailing westerly winds will more than likely always be on your nose going westbound to HNL from the west coast.. Alaska to HNL seems to not have that problem. I've flown that route as well.

DL837 ATL to HNL westbound planned for 9.52 gate to gate, the return DL836 HNL to ATL eastbound planned for 8.48 gate to gate, same equipment, A330-300,
DL1284 LAX to HNL westbound planned for 6.02 gate to gate, the return DL1283 HNL to LAX eastbound planned for 5.32 gate to gate, same equipment B767-300ER
Flights to HNL usually land on 08L which is closer to the terminal so less taxi time and the return flights back to the mainland have a longer taxi time due to taking off from 08R the reef runway.

The "Prevailing Westerlies" flow West to east, You're flying in to the wind going west and you have a tail wind flying east. And??
The tailwind could be quite stiff.
at United we had a B777 land at SFO sometime back with nearly 90K fuel on board as they had 128 kts of tail wind across the Pacific and the Capt. had to explain why he didn't heed the weather and winds aloft to go with the reduced fuel load as he had to re-clear his flight plan over anchorage anyway.
We had to defuel the airplane for it to be weighed and had to burn the 13,000 gallons of fuel in our turbine shop engine test cells as we couldn't use it on another airplane. That defuel took us half the night! from 4PM-2AM. I really doubt the Capt. got more than chewed out.
I might have doubted a 128 knot tail wind myself.
I flew P3C's in the Pacific and saw 60-80 kt tailwinds and headwinds. but never 128 kts.

strfyr51 wrote:

The "Prevailing Westerlies" flow West to east, You're flying in to the wind going west and you have a tail wind flying east. And??
The tailwind could be quite stiff.
at United we had a B777 land at SFO sometime back with nearly 90K fuel on board as they had 128 kts of tail wind across the Pacific and the Capt. had to explain why he didn't heed the weather and winds aloft to go with the reduced fuel load as he had to re-clear his flight plan over anchorage anyway.
We had to defuel the airplane for it to be weighed and had to burn the 13,000 gallons of fuel in our turbine shop engine test cells as we couldn't use it on another airplane. That defuel took us half the night! from 4PM-2AM. I really doubt the Capt. got more than chewed out.
I might have doubted a 128 knot tail wind myself.
I flew P3C's in the Pacific and saw 60-80 kt tailwinds and headwinds. but never 128 kts.

Your story is full of holes. Captains on large airlines don't determine the fuel required. That's done by dispatch whose aided by computers and load control. CPTs may request additional fuel because he's worried about WX at the destination, but it's not based on unforecast winds. I never heard of any CPT asking for defuel or a lesser fuel load because it's "too much" unless it's an obvious error and would cause an overweight landing.

Winds that strong are seldom unforecast. Every common flight altitude and track winds are reported probably hundreds of times a day and 128 knots winds are not uncommon at all. 200 knot winds are occasionally observed in the jet streams also, but the flight plan 99% of the time reflects all this.