Shamrock61 From Switzerland, joined May 2009, 1 posts, RR: 0 Posted (4 years 1 week 1 day 20 hours ago) and read 10713 times:
Hello to All,
I have a question regarding the difference in range at maximum passenger payload between the stock Airbus A319 and the stock Airbus A320.
The ranges are 1800nm for the A319 versus 2600nm for the A320, both at full pax, namely 119 and 150 passengers respectively.
Both aircraft have identical wings in terms of wingspan and nearly identical fuel capacity.
The A319’s MTOW is indicated at 64’000 kg while the A320’s MTOW is given at 73’500. That is a difference in weight of 9.5 tons in favor of the A319.
Nevertheless, at nearly identical fuel loads, the range of the A319 (in the above-mentioned configuration) is 800nm shorter than that of the A320 (in comparable configuration).
Why is that?
I notice that both aircraft I measured use different models of the CFM 56 engines; namely the CFMI CFM56-5B5 (22’000 lbs flat-rated thrust) for the A319 and the CFMI CFM56-5B4-2 (27’000lbs flat-rated thrust) for the A320.
While it is true that the engines on the A319 are considerably less powerful than those on the A320, the cruise speeds of both aircraft are essentially the same.
Furthermore, given the lighter weight of the A319 compared to the A320 shouldn’t the engines of the former consume less fuel in cruise than those of the latter?
I imagine the answer lies in the technical specifications between the two types of engines. Additionally, perhaps the A320 reaches and maintains higher cruising altitudes more quickly (given its more powerful engines), ultimately using less fuel over the course of the trip.
Nevertheless, a difference of 800nm seems a lot of mileage difference to account for simply on the basis of an aircraft flying perhaps 3-4000 feet higher than its counterpart. Maybe I’m wrong. Maybe that does make all the difference after all.
For your information, I have found my technical references on airliners.net as well as from the FAA type certification data sheets available on internet. I have cross-checked the information with other information providers, including notably Airbus and airline operators of the types in question using comparable configurations.
I hope someone can explain this for me and thank everyone in advance who will be kind enough to help me.
Tdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 81 Reply 1, posted (4 years 1 week 1 day 19 hours ago) and read 10700 times:
Quoting Shamrock61 (Thread starter): Nevertheless, at nearly identical fuel loads, the range of the A319 (in the above-mentioned configuration) is 800nm shorter than that of the A320 (in comparable configuration).
At full payload, the A320 has 31 more people (~8000 lbs) but ~18000 lbs more MTOW. Some of that delta is taken up in the extra struture but, at the end of the day, they can use some of the excess to carry more fuel.
Quoting Shamrock61 (Thread starter): While it is true that the engines on the A319 are considerably less powerful than those on the A320, the cruise speeds of both aircraft are essentially the same.
Max thrust has almost nothing to do with cruise speed, since you don't cruise at max thrust.
Quoting Shamrock61 (Thread starter): Furthermore, given the lighter weight of the A319 compared to the A320 shouldn’t the engines of the former consume less fuel in cruise than those of the latter?
Yes, the A319 will burn less fuel due to the lower weight.
Quoting Shamrock61 (Thread starter): I imagine the answer lies in the technical specifications between the two types of engines.
No. The engines are physically identical. The only difference is a programming pin in the engine that sets what it's maximum speed (maximum thrust) will be. Where the thrust ranges overlap, the two engines burn exactly the same fuel when at the same thrust. This is fairly common for families of engines...the CFM56-7 on the 737NG works the same way.
TristarSteve From Sweden, joined Nov 2005, 3855 posts, RR: 34 Reply 2, posted (4 years 1 week 1 day 19 hours ago) and read 10699 times:
There are different MTOW available.
BA A319 are 68Tons, and the Qatar A319 is 73.5 tons
So the ranges depend.
For example on the Qatar, DOH-ARN is usually a A319 with 108 pax. This is just possible, but sometimes in the winter the aux tank is used, and they go at MTOW.
If the A319 is u/s, an A320 is substituted. This is limited to the same pax load and seems to have about the same range with the same MTOW.
There are so many varieties of engine thrusts, and MTOWs it is difficult to compare.
Prebennorholm From Denmark, joined Mar 2000, 6131 posts, RR: 55 Reply 4, posted (4 years 4 days 11 hours ago) and read 10301 times:
Quoting Shamrock61 (Thread starter): The ranges are 1800nm for the A319 versus 2600nm for the A320, both at full pax, namely 119 and 150 passengers respectively.
I wonder where you get those data from since airbus.com tells that 319 max range is 3,700nm and the 320 max range is 3,000nm.
Furthermore both the 319 and the 320 can be had with many engine variants, IAE V2500 and CFM56. And both planes can be delivered with engined ranging from 22 to 27klbs.
Your numbers can be right if you have them from one specific airline operator.
Airlines can have individual planes or their whole fleet registered with considerably reduced MTOW. That way they save money on airport fees. This is very common on 320 family and 737 planes used on inter-European flights. Such planes of course have a much reduced range, ie 1,800nm instead of 3,700nm.
Most engine variants differ only in the FADEC software. The lower powered versions have the advantage that they run longer time between scheduled maintenance, and save money that way. But it is mostly just paperwork to change to another engine version.
If a 319 is used on inter-European routes on segments mostly between 500 and 1,000nm, then the airline will have it registered with much reduced weight and very likely the engine software set to lowest power = 22klbs. Anything else would be "burning good money".
On the other hand, when Atlantic Airways gets their 319 for their Copenhagen - Faroe Islands shuttle (800nm), then it will have much reduced max weight and high power engines due to the very short runway at Vagar.
Airlines tailor their planes to fit their needs in the most economic way.
Always keep your number of landings equal to your number of take-offs, Preben Norholm
Because you used the lowest available A319 MTOW and the 3rd highest available A320 MTOW.
A319 OEW is about 39,725kg for CFM engines, and 39,826 for IAE
A319 MTOW of 64Tons is the lowest MTOW version, you can get the 73.5Tons MTOW version of you want.
A320 OEW is about 41,244kg on CFM and 41,345 on IAE.
A320-100 MTOW ranges can be 66T or 68T, but the 320-200 can go from 68T to 78T.
We have the 73.5T (Air Asia) and 77T (Mandala) 320-200 MTOWs here.
Quoting Shamrock61 (Thread starter): I notice that both aircraft I measured use different models of the CFM 56 engines; namely the CFMI CFM56-5B5 (22’000 lbs flat-rated thrust) for the A319 and the CFMI CFM56-5B4-2 (27’000lbs flat-rated thrust) for the A320.
You can have your A319 fleet fitted with 25,000lbs or even 27,000lbs thrust engines also... same with the 320... if you have the V2500 or the CFM56-5Bs, it's just a matter of changing the FADEC chips or something like that... they're all the same engines for the different thrust ratings (-5As are physically different though! So don't be surprised if they have a different Max Thrust rating).
Quoting Prebennorholm (Reply 4): I wonder where you get those data from since airbus.com tells that 319 max range is 3,700nm and the 320 max range is 3,000nm.
I tend to use the FCOM2 (flight planning)... And the "Airplane Characteristics for Airport Planning" from Airbus.
The Maximum Zero Fuel Weight (ie: OEW + throw as many pax and bags and cargo as you legally can) will be 58.5T for the 319 and 62.5T for the 320... let's assume 55T for A319 and 60T for the 320... and see how far they can go on 0.78mach cruise at the highest available flight level... (assume CFM56-5Bs @ highest thrust rating used)
That means, the 319 can carry 18.5 Tons of fuel, the 320 can carry 18Tons of fuel.
For 2700NM, the 319 @FL390 needs about 14,418kgs, and the 320@FL390 needs 16,011kgs...
Now that means, there's a 4082kg spare fuel on the 319, and 1989kg spare fuel on the 320...
So, who can go further? A319 of course
Not everyone wants the Highest MTOW version/certification... why? Navigation and Handling fees per aircraft is based on one's MTOW... the higher the MTOW, the more you pay. When you don't use it, why burn excess money?
As for the fuel, there are cases when even if you don't need the highest MTOW, your operational characteristics (ie: terrain requirements on some of your destination) may require you to have the 27,000lbs thrust version... but when you don't have that requirement, why have it? You'll burn through your maintenance budget that way.
When losing situational awareness, pray Cumulus Granitus isn't nearby !