Julesmusician From , joined Dec 1969, posts, RR: Posted (9 years 3 weeks 4 days 10 hours ago) and read 3155 times:
Questions for those with a technical mind:
Suppose you operate "slowair" which instead of doing what every other airline does, this one slows down i.e. lets say on a London to Tokyo flight instead of around 12 hours they slow down and do a 14hr flight instead. This should save considerable fuel, and soon the companies financial sheets will show that they are using less fuel, and it is costing less. If the fuel costs are lower, then the fares can drop, and people will have to choice to pay less but add a few hours on their long haul flights.
The question is would this work and what would the technical problems be associated with it?
PhilSquares From , joined Dec 1969, posts, RR:
Reply 3, posted (9 years 3 weeks 4 days 10 hours ago) and read 3142 times:
No, they're not going to slow everyone else down to accomodate one aircraft. What would happen in your case is you'd be assigned a less than optimum (read lower) altitude. Your fuel burn would be even higher then and you'd lose more money!
Mandala499 From Indonesia, joined Aug 2001, 6965 posts, RR: 76
Reply 5, posted (9 years 3 weeks 4 days 8 hours ago) and read 3121 times:
Cost Indexing... Aircraft Cost / Fuel Cost...
Anyways, happens often when SQ used to operate the 310s between CGK and SIN... over the delivery in SIN, a little exchange of words about Mach Numbers... when the 310 filed for the same FL only 5 - 10 mins ahead of a 777 going the same way, someone has to be given a different altitude, or the slower one to go behind the faster one.
I'm sure Phil and his employer doesn't wanna be held up on SIN-Europe on the same flight level and behind an A310 to India/ME... Either the 310 gets a different altitude to let faster traffic through at their levels, or the faster one gets a shortcut around a dogleg (gotta love hearing SQ744/777s requesting direct PARDI out of CGK to skip MES and BTH or fellow SIN bound traffic on the same flight level but at a much slower speed)... or someone gets a deviation to let traffic through or overtake slower traffic...
Slow everyone down and eventually traffic could clog up to the next FIR! And yes, theoretically it can happen!... (eg: the first time the Taliban affected my life when they took over Afghanistan... our poor 767 can't file the higher altitude it wanted going BKK-CPH due to the Afghan airspace being closed and 744s filling up the air routes all the way to the Persian Gulf... imagine if we were to go in front of 30 744s on the same flight level... by the time we reached the Arabian Peninsula, the backlog could be all the way to the Indian FIRs! J/K (Joke the crew made during cruise)
When losing situational awareness, pray Cumulus Granitus isn't nearby !
Oryx From Germany, joined Nov 2005, 126 posts, RR: 0
Reply 6, posted (9 years 3 weeks 4 days 7 hours ago) and read 3109 times:
A totally different matter would be if it was possible to optimize aircraft to a lower cruising speed and if that could give you an improvement in fuel consumption. Additionally fuel efficiency is only one point in the economics. Delivering more seatmiles per hour with the same airfraime is another.
MrChips From Canada, joined Mar 2005, 938 posts, RR: 0
Reply 7, posted (9 years 3 weeks 4 days 5 hours ago) and read 3094 times:
Quoting Julesmusician (Thread starter): This should save considerable fuel, and soon the companies financial sheets will show that they are using less fuel, and it is costing less
Not true at all.
Most aircraft have a very specific speed at which they achieve optimal fuel economy. Flying faster or slower than that speed will increase fuel consumption over a given flight.
Most modern airliners are optimized for flight somewhere between 0.76 Mach and 0.85 Mach; of course, it varies by type, but for the most part, speeds are very close to each other.
Furthermore, the airlines have what is known as a "cost index" for each flight. This is entered into the FMS prior to the flight (or is entered into the flight planning software at dispatch), and plays a major role in determining altitudes and cruise speeds for the flight. Any deviation from the pre-determined parameters will increase the cost of the trip to the airline.