Turboprop vs. Turbofan

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1. Interesting statistics.
   Ok, I am not a specialist for virtual airlines, but I was wondering what numbers and costs are important for you in comparison to a real world airline?
   I would think that one should consider the seating capacity of an airplane to determine it’s fuel efficiency (gallons per seatmile). That would change the results a lot I think?

2. Great tests 🙂

3. Once again I made a typo in the email in my last comment and it showed another person’s avatar :-/ sorry about that…

   I was saying that the tests are great 🙂

4. Html: The tests were done to compare fuel consumption and time enroute.
   Html has a good point, however… the ATR72, CRJ700, and F70 are in the same category of seat capacity and probably the 146-200. The Dash 8 Q300 and CRJ-200 are in the same category regarding seats. This will help in further determining the best aircraft for the route. Obviously, the 190/195 and F100 don’t have competition in my test. Perhaps the Dash 8 Q400 may be of interest here.

5. I’ve tried to develop a system that also includes cost of operation – both fixed and variable, along with crew costs – but have not found adequate information (that was free) – and was not willing to pay to obtain these costs (which are available, but for a price.)

   Has anyone run into a reliable source for these?

6. Gives at least a guideline… there should be some other things possible to find out on the Conklin de Decker site: http://www.conklindd.com/CDALibrary/ACCostSummary.aspx

   Best regards,

   Phil

7. Yes, Conklin & de Decker is a good source of information for that. One can als find a lot of more detailed cost analysis from them if you search the net using the company name + aircraft type. Example for the Boeing 737 BBJ: http://www.aviationchina.com.cn/manager/uploadfiles/1311564620968.pdf

8. Just a comment or two from a former mechanic for a commuter airline. I do find it hard to believe that costs for operating a turboprop are that much less than a pure turbine (jet) engine. First, with two turboprop engines, you have four separate logbooks which must be kept up. One for each engine and one for each propeller. Propeller maintenance costs can run very high. Especially if the aircraft is subjected to FOD which is often found on tarmacs and taxiways of smaller airports. Propellers can be dinged up in a hurry, and these nicks and dings have to be inspected and repaired on a regular basis in addition to standard turbine engine repair costs. Propellers tend to pick up more FOD than a standard jet engine will ingest through the intake. Perhaps the savings comes through fuel burn, of which the turboprop would have the advantage. But, I do wonder if that advantage would be offset by increased maintenance costs.

9. That’s very interesting, Owen, and thanks for your input from the professional side. Jet engines have 20+ blades that have to be maintained. I don’t know much about the toughness of prop vs. jet blades but I have to wonder about the cost, too. The cost of keeping a log on each prop blade has to be very small if you’re just talking about the process of a tech writing his/her findings at each maintenance stop. At a rate of $25/hr(?) it can’t take more than an hour to write the info into the log. I wonder how much logging is done on a jet engine with it’s multiple stages/blades. Anyone reading who has experience on jet engines?

10. Propeller nick and dings sometimes have to be inspected by X-ray or dye penetrant, depending on the damage, just as turbine blades do. However, propellers also have major inspections due where the props have to be pulled and the components inspected at certain hourly intervals. Also, another problem with turboprops is the gear reduction system. The gear reduction system is another big part of engine inspection, especially on major inspections. Then there is the matter of the controllers. They too, must be inspected and tested before returning to service at certain scheduled intervals. Generally, the turbine does have it over the turboprop as turbines can run at longer hourly intervals between inspections.

11. Having run the operations, training and maintenance operations of a real world small air operation I can tell you that Specific Fuel Consumption and Seat Mile Cost are not the only things that you look at for a fleet of aircraft.

    Commonality is a big cost saver in maintenance, training and offers huge flexibility from an operations standpoint.

    If I have a single aircraft for the 300nm market then a second aircraft for the 300nm to 1000nm market then I must maintain two different aircraft (which increases my cost in maintainers, spare parts, and special tools), I have to have two training pipes (with the additional costs in support systems) and I have zero flexibility across the two airframes.

    The money I can save in commonality far outweighs the money saved in fuel consumption which is why you see so many regionals going to an all jet fleet.

    Finally, there is public perception. They believe that jets are modern and are thus safer than turboprops. If you fail to offer jet service then you are giving your competitor an advantage in the public perception department.

12. For this to work, you also have to look at the average leg length and time above 10,000 feet. If you have short legs, both the jets and the turbo props will be constrained by the 250 knot limit – and likely even slower in congested markets.

    So yes the jet goes faster, but only above 10K feet. It is not significantly faster say, between, Portland and Seattle to fly on one of horizon’s crjs versus one of their q400s becuase so little of the flight is above $10,000 feet.