pilot advice needed

[intrepidvoyager]

Hi ............. I am trying to contact a 717 – 200 pilot who can give me an idea of how much fuel would be used on a 110 mile flight with 123 passengers. That’s the flight from Oahu to Kauai. I am working with a group on Kauai opposed to the Superferry. Hawaii Superferry claims that the Superferry has a lower carbon footprint per (RPM) than the 717-200 flown by Hawaiian Airlines. We say nonsense. The Superferry burns 6000 gallons of diesel to transport 500 passengers the 110 miles by sea. We estimate that 123 passengers can be flown on a 717-200 for less than 1000 gallons of jet fuel , perhaps as little as 700 gallons, but are not sure. If you can help that would be greatly appreciated. If you would like to call me you can reach me at 604 266 6306. If you are interested in the overall picture please visit boycottsuperferry.org …………. Thanks, Bob

 

[citrus jock]

Hi ............. I am trying to contact a 717 – 200 pilot who can give me an idea of how much fuel would be used on a 110 mile flight with 123 passengers. That’s the flight from Oahu to Kauai. I am working with a group on Kauai opposed to the Superferry. Hawaii Superferry claims that the Superferry has a lower carbon footprint per (RPM) than the 717-200 flown by Hawaiian Airlines. We say nonsense. The Superferry burns 6000 gallons of diesel to transport 500 passengers the 110 miles by sea. We estimate that 123 passengers can be flown on a 717-200 for less than 1000 gallons of jet fuel , perhaps as little as 700 gallons, but are not sure. If you can help that would be greatly appreciated. If you would like to call me you can reach me at 604 266 6306. If you are interested in the overall picture please visit boycottsuperferry.org …………. Thanks, Bob

There are way too many variables in your question to give you just one answer. Is there a departure/arrival procedure or preferred route between the two cities? If so, then the 110 miles you quoted would increase, thus increasing the fuel burn. If you depart/arrive during a peak time (if there is such a thing at these airports; I don't know, because I've never been there), your fuel burn would increase due to longer taxi times and vectors/slowing to follow other aircraft. Is the weather at these cities such that they usually require an alternate airport, requiring more fuel to be carried, which equals more weight, which equals more fuel burn. Our (AirTran) aircraft are equipped with an FMS that you program prior to departure. Part of the data we input into the FMS is a number called the cost index. We use the number 25, which gives us a relatively low (not the lowest) fuel burn per mile flown. Why not use the lowest, you might ask. It's because if we did fly slower, burning slightly less fuel, our flt. time would increase, therefore increasing the labor costs of the crew. The cost index concerns the total cost of aircraft operation, not just fuel. If, as in your situation, you're not concerned with crew costs, I would think that you would still use a number close to 25, because in flying slower, you would eventually get to a point that you're using more fuel flying slower because the airplane is in the air longer (lower fuel used/hour for a longer time versus slightly higher fuel used/hour for a shorter time). The FMS also gives you an optimum (based on fuel efficiency) cruise altitude for a given route, considering aircraft weight, route distance, and arrival altitude crossing restrictions. This "optimum" cruise altitude requires (per the FMS) that the airplane be at the optimum cruise altitude for a minimum of 15 minutes, which is not always, well...optimum, especially on shorter distance flights, like yours. So, having said all of that, and having no experience flying in Hawaii, all I could do is take a guess in answering your question.

Throwing out all of the variables listed above, and assuming that if I flew this flight, I would be the only airplane in the airspace on this route, I would guess that a cruise altitude of about 15,000 ft. would be best, and my total fuel burn would be around 3500 lbs. Adding 250 lbs. on each end for taxi, the total for the trip would be around 4000 lbs. Again, keep in mind that this assumes I don't have to wait in line to take off, I'm cleared to make a continuous climb to cruise altitude, and descent/airspeed for approach is my discretion (things I can only dream about while flying in and out of ATL). At 6.7 lbs./gallon of fuel, this would be 597 gallons of fuel. Our aircraft are configured to hold 117 pax, so the additional weight of 6 pax would add very little to those numbers. When you start to add the above variables back into the equation, the fuel burn increases. You would also add 350 lbs./hr. for APU usage if there is no jetway power and/or external air conditioning for ground operations.

As for environmental "footprint", it's possible that burning more of one type of fuel leaves less of a footprint than burning less of another type of fuel. I don't have a clue what's left in the air when diesel is combusted versus when jet fuel is combusted. I do know that when we took delivery of the first 717, part of AirTran's advertising included how environmentally friendly the Rolls Royce engine is. There may still be a link on our website (airtran.com) that discusses this. Hope some of this helps, and good luck.