>>>I have a curiosity question maybe someone could answer. Living in Rhode Island, at the present time there is alot of controversy about runway length at PVD (whether to extend, approx. 7,800 ft to 9,000 ft). The airlines would like the longer runway to be able to fly coast to coast with a full load. Understandable for safety concerns.
Like the Hertz commercials say, "not exactly". It's NOT a safety concern, per se. Either a runway is long enough to allow takeoff at a particular weight (which, as you infer, varies with actual passenger load, but also, temp, winds, etc.) or it doesn't. If a flight is too heavy, weight is removed until it's again within max permissible limits. Another option is for the flight to make an additional stop enroute, thus reducing the total amount of fuel aboard, and making the aircraft lighter. A full flight PVD-LAX might have to operate PVD=PIT or PVD-IND first, and will thus require less fuel than the PVD-LAX option. The longer runways at PIT/IND, and the shorted total distance fromthere to LAX, will permit non-stop operation. If the PVD-LAX flight only had 50 folks on it, yeah, you'd be going non-stop.
>>>Recently, I noticed, a few of the major carriers are flying or will start to fly 777's and 767-300's from Maui (OGG) to LAX, SFO and even as far as DFW (Dallas). OGG's main runway is no longer than ours at PVD. If they are so concerned about PVD's main runway being too short for coast to coast flights, why would these same airlines allow the wide bodies to fly out of OGG? One would have to assume when these planes leave OGG that they are full.
This sort of relates to your first question, and yes, the assumption that OGG-LAX/SFO/DFW flights are FULL is just that--an assumption.
Without the benefit of charts here at the house to confirm these details, I'm going to assume that PVD and OGG are essentially at sea level elevations, and that there are no obstacles affecting performance. ((One could have a 10,000 foot runway, but if there are obstructions (terrain, buildings, etc.) within a couple of miles from the departure end of the runway, that long runway is not going to provide optimal weights as an obstacle-free runway would.)) Runway length is important, and the longer the better, but it's just one factor in the context of your question.
Allow me to make a simplistic side-by-side comparison, assuming all the following data:
3000nm 3000nm (Assumed distance)
460kt 460kt (Assumed 767 true air speed)
+75kt -75kt (Assumed tail/headwind)
535kt 385kt (Resulting groundspeed)
5:36 7:47 (Resulting time enroute)
56,100 78,000 (Resulting 767 fuel burn, @10,000 pph)
It's not just how long the runway at the takeoff point is--it's also *how* the aircraft that uses it will be operated. As you can see from these admittedly crude numbers, there's a difference of 21,900 pounds in fuel burn here on the same assumed 3,000nm trip. (Someone can correct me with the actual PVD-LAX and OGG-XYZ distances, but the principle remains unchanged). That same 21,900 punds equates to about 109 passengers and their bags, which might explain why one could operate OGG-XYZ with a full aircraft, but PVD-LAX could only operate full minus 109 folks. Turning the situation around, one could probably operate eastbound PVD-London with no problem, and have problems westbound OGG-Tokyo.
Lot's of other variables involved, such as aircraft type, engine version, runway condition (dry, wet, snow, slush), altimeter setting, and surface winds, but all of these can either help/hurt the situation depending on how the aircraft is planned to be used.
Hope all this makes sense...
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.