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Does A Heavy A320 Restrict The Aircraft Altitude.  
User currently offlinegilesdavies From United Kingdom, joined Dec 2003, 3041 posts, RR: 2
Posted (1 year 9 months 7 hours ago) and read 4333 times:

I have done a search and could not find anything and apologise if this has been discussed before...

Im just home from a holiday in Sharm El Sheikh, Eqypt and flew with easyJet on their LTN-SSH service, both ways and the route is about 2435 miles according to GC Maps.

On both journeys before take off, the pilot came on and advised us of the route we would be taking, flight time, altitude, etc...

On the outward journey, the pilot explained we would initially climb to 27,000 feet and then said "after we have lost some weight we will climb to 37,000 feet..." At the time didn't really think much about it.

But on our homeward journey back to Luton, the pilot came on at Sharm before take off, commenting how they had excellent tail winds coming from Luton yesterday and did the 2400 miles journey in 4hrs 19mins! BUT as a consequence they homeward journey would be considerable longer as we will have a head wind and the flight time would be 6hrs 15mins, as opposed to the 5hrs when I flew to Sharm the week before and this is roughly the usual block time.

The pilot went on to describe our route home, and went on to apologise the flight could be a little bumpy for the first hour as we will be only climbing to 22,000 feet, and might get caught in some weather as opposed to flying over it, and then went on to say we will then gradually climb to 39,000 feet over the next two hours, "when the flight should smooth out..."

In the end the flight was actually quite smooth throughout, other than for the first 10 mins, when there was some minor turbulence.

The take off from Luton outwards, seemed very powerful and only used about three quarters of the 7000ft runway, but from Sharm the take off run seemed very slow in comparison and used most of the airports 10,000ft runway.
(This is just an observation and might have nothing to do with the weight.)

Both the outward and homeward flights were virtually full, I think easyJet's A320's hold 184 passengers, which is the highest capacity of any operator of this type.

I have flown to Sharm El Sheikh before with Thomson on their 752's and 738's from LTN and not ever noticed the gradual climbs.

Is this a characteristic of the A320, when flying longer sectors with a heavy load or if this same for most aircraft?

I have heard of similar issues with US Airways when flying transcon routes with the A321, and flying from the UK to SSH is a very similar distance and flying time.

Monarch have recently started using their A321's on their new SSH scheduled services, do they suffer similar restrictions to easyJet, especially when they operating with 220 passengers? Previously the routes have been operated with 757's and A300's when they were flying charters.

I know their are airlines like BA/BMI that fly longer sectors with the A320/A321, but these are operating with a lot fewer passengers.

17 replies: All unread, jump to last
 
User currently offlinesweair From Sweden, joined Nov 2011, 1828 posts, RR: 0
Reply 1, posted (1 year 9 months 7 hours ago) and read 4276 times:

The A320s seem to cruise quite low at first I have noticed, as well as being runway hogs, the A321 I flew took most of ARNs long runway to get off. I know they can take off with less thrust to save on engines and fuel but still.. WBs seem to have more ooomph than NBs in general, not counting the 752 rocket. 738s are slow off the runway too, esp in hot weather I have noticed, packed with low fare travelers..186 filled seats and their millions of bags..

User currently offlineAR385 From Mexico, joined Nov 2003, 6369 posts, RR: 32
Reply 2, posted (1 year 9 months 7 hours ago) and read 4246 times:
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I think it is an issue with every aircraft. On FRA-EZE one time our initial altituted was 28,000ft or 29,000ft. It was a 744 and we were delayed leaving the gate because due to excess weight we had to offload cargo. We didn´t climb until past the The Canaries.

Your low altitutde on the return is too low though, and it was probably due to the combination of headwinds and traffic.


User currently offlinethreeifbyair From United States of America, joined Aug 2007, 699 posts, RR: 1
Reply 3, posted (1 year 9 months 7 hours ago) and read 4138 times:

Quoting AR385 (Reply 2):
I think it is an issue with every aircraft. On FRA-EZE one time our initial altituted was 28,000ft or 29,000ft. It was a 744 and we were delayed leaving the gate because due to excess weight we had to offload cargo. We didn´t climb until past the The Canaries.

Same thing with a DL MD-90 - low cruise altitudes when fully loaded on the MSP-West Coast routes. Lots of fuel onboard.


User currently offlineatlengineer From United States of America, joined Jul 2010, 81 posts, RR: 0
Reply 4, posted (1 year 9 months 7 hours ago) and read 4116 times:

Quoting gilesdavies (Thread starter):
The pilot went on to describe our route home, and went on to apologise the flight could be a little bumpy for the first hour as we will be only climbing to 22,000 feet,

I suspect this is because they had to take on extra fuel (and weight) due to the headwinds. With the extra weight of the aircraft, they couldn't climb to 37.000 feet because they can't get enough lift at that altitude in the thin air to equal the weight of the aircraft. As they begin to burn off fuel (and weight), they can start climbing higher.

ATLengineer


User currently offlineAA737-823 From United States of America, joined Mar 2000, 5875 posts, RR: 11
Reply 5, posted (1 year 9 months 6 hours ago) and read 3805 times:

The A320 is indeed limited by the performance of it's underwhelming wing. The A320 wing was LOTS better than the 737-3/4/500 wing, but NOT as good as the 737NG wing (as you'd expect, given that the manufacturers update their products in tick-tock fashion).
A six hour leg can be a challenge for the A320, though less so for an A319. USAirways sometimes makes fuel stops on the PHX-ANC route when they operate with 320's, which is why, I opine, they typically schedule 319's.

Quoting AR385 (Reply 2):
I think it is an issue with every aircraft.

It can be; some are worse than others, though.

Quoting threeifbyair (Reply 3):
Same thing with a DL MD-90 - low cruise altitudes when fully loaded on the MSP-West Coast routes. Lots of fuel onboard.

The MD-90 is a particularly under-qualified aircraft. Douglas chose not to invest in a new wing for the plane, instead opting to slap MD-80 wings onto a stretched and heavier airframe. The MD-80 already has trouble with climbing to cruise altitude, and makes an ordeal out of it. The MD-90, though it has far better engines which help things quite a bit, just needed a new wing badly. The MD-90-30 is very good at some things, but this is not one of them.


User currently offlinePihero From France, joined Jan 2005, 4608 posts, RR: 77
Reply 6, posted (1 year 9 months 3 hours ago) and read 3501 times:
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Quoting gilesdavies (Thread starter):
On the outward journey, the pilot explained we would initially climb to 27,000 feet and then said "after we have lost some weight we will climb to 37,000 feet..

The 320, at MTOW can reach FL 370 if the pilot wanted... FL 350 would be closer to optimum. That limitation at 27000 ft is rather typical of the Level clearances one would get initially eastbound from the UK. The final level (around Athens ) would be FL 390, the max for this type.

Quoting gilesdavies (Thread starter):
I have flown to Sharm El Sheikh before with Thomson on their 752's and 738's from LTN and not ever noticed the gradual climbs.

It's not gradual, it will be a series of step climbs : FL 330, then 350, then 370, then 390. Passengers rarely notice them.

Quoting gilesdavies (Thread starter):
Is this a characteristic of the A320, when flying longer sectors with a heavy load or if this same for most aircraft?

On a trip that long, yes, it is usual. The 738 gets higher quicker and ends up higher, too.

Your return trip is a bit more complicated. The initial restriction to FL 220 is, without a doubt, due to traffic reasons, which could be political, too : that area is monitored by at least three countries before you come into the responsibility of the Greek ATCs.
The lower than you expected levels could be a case of "flying under the jetstram" on what we call a "wind / Altitude trade" : basically you burn less fuel , time-wise, but as - because of the wind - your ground speed is lower than at a lower altitude where you benefit from less headwind and a better true airspeed, you end up losing time and fuel.

Quoting AR385 (Reply 2):
On FRA-EZE one time our initial altituted was 28,000ft or 29,000ft. It was a 744

The 744 in this respect is a very frustrating airplane to fly, especially when you share your airspace with all these hot-rod twins going the same way as yours : initial level is - you're right - around FL 290 or 300 and then these little bastXXXs have hogged the upper levels... and you're stuck, worrying about your fuel status...



Contrail designer
User currently offlineRoseflyer From United States of America, joined Feb 2004, 9671 posts, RR: 52
Reply 7, posted (1 year 9 months 2 hours ago) and read 3480 times:

I agree with Pihero that 22,000 had little to do with weight. The A320 can go way higher at MTOW. The A320 goes higher than previous generation narrow bodies like the MD80 or 737 classic. However the 737NG can go higher. Boeing pushed the 737NG range and altitude to be a bit more than the A320.

Usually it is only the heavy wide bodies that are restricted to below 30,000ft. The 737, 757 and A320 can all go above 30,000 at MTOW. A340s, 777s and 747s are the airplanes that have to start around 30,000 ft before step climbing on 5000+ mile routes.



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User currently onlineStarlionblue From Greenland, joined Feb 2004, 17077 posts, RR: 66
Reply 8, posted (1 year 9 months 2 hours ago) and read 3477 times:

Quoting Pihero (Reply 6):
Quoting gilesdavies (Thread starter):
I have flown to Sharm El Sheikh before with Thomson on their 752's and 738's from LTN and not ever noticed the gradual climbs.

It's not gradual, it will be a series of step climbs : FL 330, then 350, then 370, then 390. Passengers rarely notice them.

Sometimes you'll hear the engines power up a bit, but that's about it.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineLH707330 From United States of America, joined Jun 2012, 812 posts, RR: 0
Reply 9, posted (1 year 8 months 4 weeks 1 day 23 hours ago) and read 3405 times:

Quoting Roseflyer (Reply 7):
A340s, 777s and 747s are the airplanes that have to start around 30,000 ft before step climbing on 5000+ mile routes.

IIRC the 340 can start a bit higher (31-32k) than the 777 and 747 because it has a big wing for its weight, but in principle you're right.


User currently offlineMax Q From United States of America, joined May 2001, 4680 posts, RR: 19
Reply 10, posted (1 year 8 months 4 weeks 1 day 21 hours ago) and read 3330 times:

You can also stay lower on purpose to avoid the worst of the headwinds.


The best contribution to safety is a competent Pilot.
User currently offlineferpe From France, joined Nov 2010, 2804 posts, RR: 59
Reply 11, posted (1 year 8 months 4 weeks 1 day 13 hours ago) and read 3177 times:

The reason the twins can go higher for initial cruise is because they need stronger engines to certify for the one engine out case, they are therefore stronger climbers. Normally one give up when the engines can not climb you faster then 300ft/minutes according to my engine design book (check out the TF42 thread to see these rules in action) but I suspect other rules can also apply like the wings coming to close to buffeting (the reason the 737 classics had to start on lower FL I guess).


Non French in France
User currently offlineLH707330 From United States of America, joined Jun 2012, 812 posts, RR: 0
Reply 12, posted (1 year 8 months 4 weeks 1 day 8 hours ago) and read 2987 times:

Quoting ferpe (Reply 11):

True, but the 777 has a lower initial cruise because of its high wing loading....


User currently offlineferpe From France, joined Nov 2010, 2804 posts, RR: 59
Reply 13, posted (1 year 8 months 4 weeks 1 day 7 hours ago) and read 2948 times:

Quoting LH707330 (Reply 12):
True, but the 777 has a lower initial cruise because of its high wing loading....

Absolutely, there is nothing wrong with the power of those GE90-115s  Wow! , the limit is the transonic margins stopping further climb. The GE90-155 Take Off 5 minute power to MTOW ratio is 29.8% which shall be compare to other twins which are everywhere from 25-29% (except for the 757 of course, 31.4%  ). All this compared to the 4 holers at 11% (A380) to 15% (A340).

Now the GE90 has a bypass ratio of 9+ so it looses power with speed but there is plenty of grunt left at their initial FL of some 310   .

[Edited 2013-02-03 12:58:38]


Non French in France
User currently offlinePihero From France, joined Jan 2005, 4608 posts, RR: 77
Reply 14, posted (1 year 8 months 4 weeks 1 day 6 hours ago) and read 2885 times:
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Quoting LH707330 (Reply 12):
but the 777 has a lower initial cruise because of its high wing loading....

...in other words, it's underwinged, which has never been said in this forum.   



Contrail designer
User currently offlineLH707330 From United States of America, joined Jun 2012, 812 posts, RR: 0
Reply 15, posted (1 year 8 months 4 weeks 1 day 5 hours ago) and read 2856 times:

Quoting Pihero (Reply 14):
Quoting LH707330 (Reply 12):
but the 777 has a lower initial cruise because of its high wing loading....

...in other words, it's underwinged, which has never been said in this forum.

Not sure if you're being sarcastic there, but per my calculations (wikipedia data), the 77W has the second highest wing loading in this group:

Plane: kg/m2
772: 577
A330: 644
A388: 678
77E: 694
744: 756
A343: 760
77W: 820
A346 HGW: 864

I've always heard that the 340s have a higher initial cruise than a 744, despite having higher wing loading, with the 346 taking the cake. Thus there are a few possible explanations, could you help me identify which ones apply?
1. I'm misinformed about initial cruise re the 777/A340
2. The Boeing/Airbus wing area calculations are different and I'm comparing apples and oranges
3. The high T/C Airbus wing plays a role
4. I'm barking up the right tree and you're yanking my chain


User currently offlinePihero From France, joined Jan 2005, 4608 posts, RR: 77
Reply 16, posted (1 year 8 months 4 weeks 1 day 4 hours ago) and read 2832 times:
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Quoting LH707330 (Reply 15):
Not sure if you're being sarcastic there

Of course I was. Climb performance is a lot more complicated and involves a lot more than wing loading.



Contrail designer
User currently offlineLH707330 From United States of America, joined Jun 2012, 812 posts, RR: 0
Reply 17, posted (1 year 8 months 4 weeks 23 hours ago) and read 2724 times:

Quoting Pihero (Reply 16):
Quoting LH707330 (Reply 15):
Not sure if you're being sarcastic there

Of course I was. Climb performance is a lot more complicated and involves a lot more than wing loading.

Got it. I imagine the 777-300ER climbs well but tops out early, is this correct?


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