gkirk
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A340-300 Underpowered.....?

Thu Aug 29, 2002 9:22 pm

I think not!
Look at this Air Jamaica A340-300 climbing out of MAN, I think its proof to all the A340 cynics (including me in the past), that the A340-300 is no way underpowered  Big thumbs up

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EGGD
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RE: A340-300 Underpowered.....?

Thu Aug 29, 2002 9:24 pm

Yeah you should watch PIA's 742's and 743's at MAN, frightening stuff!
 
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yyz717
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RE: A340-300 Underpowered.....?

Thu Aug 29, 2002 9:24 pm

I think the issue is not so much on take-off, but that it can't reach cruising altitude quickly with full payload. Or rather, as quickly as the 772 or 744.

I dumped at the gybe mark in strong winds when I looked up at a Porter Q400 on finals. Can't stop spotting.
 
David_itl
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RE: A340-300 Underpowered.....?

Thu Aug 29, 2002 9:29 pm


Can I allege that there might not have been a big load of passengers? One of the services in the middle of June had a whopping 58 passengers on board. I do hope that the service has become more popular.

David
 
MD88Captain
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RE: A340-300 Underpowered.....?

Thu Aug 29, 2002 9:29 pm

GKirk. Your picture proves nothing. Not a thing. Even a 727 will leap off the ground when it is lightedly loaded. The 340 is a slow climber and eats up tons of runway during takeoff. This is just a characteristic of the airplane. It doesn't mean it is a bad airplane. It obviously fits the needs of many airlines. I think it is similar to the venerable 727. Underpowered, but with many other redeeming qualities.
 
David_itl
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RE: A340-300 Underpowered.....?

Thu Aug 29, 2002 9:31 pm


My best memory is of Aer Lingus 747 EI-BED almost running out of runway when taking off circa 1982. Best take-off I've heard about was done by a Learjet that reached 3,500 feet over Tatton Park.

David
 
gkirk
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RE: A340-300 Underpowered.....?

Thu Aug 29, 2002 9:33 pm

David, yes that could be true. Have any of the MAN JM services been completly full or are they not doing too great. What about the BWIA flights?

MD88Captain, thanks for biting my head off  Yeah sure
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bobcat
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RE: A340-300 Underpowered.....?

Thu Aug 29, 2002 9:34 pm

A340 underpowered? I don't think China Airlines A340 pilots will agree with that statement...  Big grin

(especially the ones who took off from a taxiway at Anchorage)
 
David_itl
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RE: A340-300 Underpowered.....?

Thu Aug 29, 2002 9:41 pm

BWIA were reported to have got off to a good start according to their director of sales for the UK & Ireland.

As for Air Jamaica, I haven't heard too much of how good/bad a start it's had. With these services starting, the Manchester Evening News did a little piece and mentioned that highly loaded flight.

Presumably the bank holiday would have seen the flights full or nearly full (some 210,000 passengers were expected over the three day period on 1700 flights).

David
 
Singapore 777
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RE: A340-300 Underpowered.....?

Thu Aug 29, 2002 9:53 pm

The A340-300 can't be underpowered otherwise it wouldn't be flying today. It wouldn't even be certified!
 
Greg
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RE: A340-300 Underpowered.....?

Thu Aug 29, 2002 10:11 pm

Doesn't prove anything.
It could be empty.
 
sllevin
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RE: A340-300 Underpowered.....?

Thu Aug 29, 2002 10:24 pm

All four-engined aircraft are going to have inferior climb performance compared to twinjets, for the simple reason that they EXIST to have a worse power-weight ratio.

All aircraft are certified and operated on the assumption that they will lose an engine. In a twinjet, this means you lose 50% of your thrust, and all remaining thrust is asymetrical. So when you *don't* lose an engine you have lots of power available.

In a four engine aircraft, losing an engine means only losing 25% thrust and half the thrust on one side. That's significantly more engine-out performance; therefore, a four engined aircraft can take off significantly heavier even if the net thrust with all four engines working is the same.

Steve
 
Guest

RE: A340-300 Underpowered.....?

Fri Aug 30, 2002 12:45 am

This past Sunday I was on a World Airways MD-11 that was fully loaded, and this thing with three 62,000lb thrust PW4000 series engines had a fast takeoff roll and lifted off the runway very quickly with the same angle as the A340-300 in the picture, and reached cruising altitude within a few minutes. The A340-300 needs engines with thrust of around 40,000lbs to help it climb better.
 
Scorpio
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RE: A340-300 Underpowered.....?

Fri Aug 30, 2002 12:49 am

I'll take OA340's role here for a minute:

TEDSKI, how about that Airliner Economics 101 class? Still didn't get around to it, I see...
 
EssentialPowr
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RE: A340-300 Underpowered.....?

Fri Aug 30, 2002 2:11 am

Instead of arguing, why not provide some simple thrust to weight ratios?

From the web page, I selected the heaviest version of each type along w/ the max thrust option for that subtype...

A340-500
MGTOW 804700 lbs; 4 Trent 553s at 53k thrust ea = .2635

A340-300
MGTOW 608300 lbs; 4 CFM 56 at 34k thrust ea = .2236

A340-200
MGTOW 606300 lbs; 4 CFM 56 at 34k thrust ea = .2243

B747-400
MGTOW 875000 lbs; 4 P&W 4063s at 63.3k thrust ea = .2894

ERJ (145)
MGTOW 48500 lbs; 2 A3007 at 7.4k thrust ea = .3052

B757-200
MGTOW 255000 lbs; 2 P&W 2040s at 40.1k thrust ea = .3145

Climb performance is a function of excess thrust. The A340-300 has the lowest thrust to weight ratio in the A340 family. The A340 family in particular has low thrust loadings in comparison to other contemporary jet transports. The A340-300 is a poor climber, and the numbers reflect this. And has been stated, if one watches enough takeoffs, the A340's poorer climb performance is visually apparent.

cheers-
 
mandala499
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RE: A340-300 Underpowered.....?

Fri Aug 30, 2002 2:19 am

If an A340 takes off using full T/O rather than Flex T/O mode, it can produce some "normal" take off displays like the pic above...

Mandala499
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
EssentialPowr
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RE: A340-300 Underpowered.....?

Fri Aug 30, 2002 3:17 am

You must not understand the math or the definitions...

The thrust/weight ratios I provided are max thrust, max weight. For a light a/c, that type of deck angle is typical.
 
Skystar
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RE: Questionable Comments

Fri Aug 30, 2002 9:54 am

Tedski wrote that a full MD-11 reached cruising altitude within a few minutes. A few minute is about 3 to 4 minutes. Given a typical lowerish cruising altitude of FL310, that means you'd be climbing at almost 8000fpm - sorry credibility goes on this one.

Not bloody possible in my books, empty plane or full one.

Sllevin,

You're generally right, but there are a few exceptions - eg. compare the 346 with a few 332s and some 777s.

Also remember that the climb performance of a quadjet is superior to that of a twin in an engine out situation - it has to be:

Quads 3.0% climb gradient
Twins: 2.4% climb gradient.

Cheers,

Justin
 
LMP737
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RE: A340-300 Underpowered.....?

Fri Aug 30, 2002 9:55 am

There was an article about Singapore Airlines fleet plans a couple of years ago in AV Week. In the article it was mentioned that a 777 leaving the same as a A340 on the Singapore-London route will arrive 30 minutes earlier.
Never take financial advice from co-workers.
 
Boeing4ever
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RE: A340-300 Underpowered.....?

Fri Aug 30, 2002 12:30 pm

I think not!
Look at this Air Jamaica A340-300 climbing out of MAN, I think its proof to all the A340 cynics (including me in the past), that the A340-300 is no way underpowered


Take a look at this...


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FDXmech
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RE: A340-300 Underpowered.....?

Fri Aug 30, 2002 12:37 pm

If an A340 takes off using full T/O rather than Flex T/O mode, it can produce some "normal" take off displays like the pic above...

Most takeoffs by any type are not maximum power.
You're only as good as your last departure.
 
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RayChuang
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RE: A340-300 Underpowered.....?

Fri Aug 30, 2002 12:50 pm

I've seen AF and SQ A340-300's take off from Runway 28R at SFO.

Talk about a runway hogger and slow climber! The A343's from what I saw use as much runway as a 747-400 on the takeoff roll and the climb rate is definitely leisurely compared against even a full-loaded 744 after takeoff. Small wonder why SQ pilots expressed concern about the A343 being unable to dodge the poor weather over the Bay of Bengal on flights to Europe from SIN.
 
kaitakfan
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RE: A340-300 Underpowered.....?

Fri Aug 30, 2002 3:24 pm

EssentialPowr,Thank you for actually making an intelligent post and using the mathematical facts instead of opinions. Nothing more needs to be said. The facts have been layed out. Opinions are useless in this discussion. Its a shame there wasn't a pic of the 747-400 I was on going from ORD-HKG. Pretty damn heavy load, hot day in Chicago. The take off roll pushed a minute long and we were slow to get alt. If people see this take place then can it be said the 747-400 is now under powered? I think not! Atmopsherical conditions and weights can work wonders in cases like this. A steep climb out pic compared to facts... I wonder who is correct here?!?
 
Guest

RE: A340-300 Underpowered.....?

Sun Sep 01, 2002 3:09 am

I didn't keep track of the time the MD-11 took to reach it's cruising altitude, so I shouldn't have said in a few minutes, but it was quick with the power the three PW4000 series engines had of 62,000lbs. This aircraft was not a slow climber.
 
Hardkor
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RE: A340-300 Underpowered.....?

Sun Sep 01, 2002 6:30 pm

Would an A340 be more at risk for an accident if the plane blows an engine during takeoff compared to other wide bodied aircraft?
 
mandala499
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RE: A340-300 Underpowered.....?

Sun Sep 01, 2002 9:04 pm

No because it'll loose only 25% of it's thrust, which means 25% of the reverse thrust too !

Mandala499
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
Rick767
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RE: A340-300 Underpowered.....?

Sun Sep 01, 2002 9:26 pm

Mandala499

Reverse thrust is not taken into account in the calculations for a normal rejected takeoff (Accelerate-Stop Distance Calculations).

Main reason is that airliners fly quite often with one inop reverser (locked out).

It's just speedbrakes and maximum wheel brakes. We would of course use reverse thrust to stop in an RTO, even from just one engine, but any additional retardation provided is a bonus to the performance figures.

In answer to Hardkor's question, no it is no more at risk. All aircraft have to comply with the same critera for the Accelerate-Stop scenario and there is plenty of safety built in.
I used to love the smell of Jet-A in the morning...
 
mandala499
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RE: A340-300 Underpowered.....?

Mon Sep 02, 2002 3:22 am

Did I say it was taken into account in the RTO & runway length requirement calcs ?  Smile

When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
Rick767
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RE: A340-300 Underpowered.....?

Mon Sep 02, 2002 8:43 am

In what other way would it have an effect on the stopping distance in a RTO situation?
I used to love the smell of Jet-A in the morning...
 
EGGD
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RE: A340-300 Underpowered.....?

Mon Sep 02, 2002 9:07 pm

B4e - it works both ways:


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I believe both aircraft were heavily loaded at the time.

I don't think its underpowered, rather not-overpowered. Airbus have got the better ratio here because it means that the a/c virtually uses less power to do the same job.

hmmmm.

Dan  Smile
 
Boeing4ever
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RE: A340-300 Underpowered.....?

Tue Sep 03, 2002 12:19 pm

As opposed to a twinjet that can lift off a runway faster with only two engines? Kinda like 777 or A330 eh?

hmmmmmmm

B4e-Forever New Frontiers
 
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Francoflier
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RE: A340-300 Underpowered.....?

Thu Sep 05, 2002 3:06 am

Hi all,

Numbers have proved the 340's to be slow climbers, but as EGGD mentionned, it does the exact same job with the same safety as a "sport-twin" or a 744 on less power, thus less fuel... And companies love that.

This I think is the real strong point of the a/c, and how airbus' brainiacs designed it. As a pilot or aviation fan, of course, it lacks some balls...
But hey, I know pilots don't pay for gas...

Regards,
I'll do my own airline. With Blackjack. And hookers. In fact, forget the airline.
 
EssentialPowr
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RE: A340-300 Underpowered.....?

Thu Sep 05, 2002 4:01 am

I'd rather have the higher thrust to weight ratio capability (ie higher installed thrust) and simply not use it as often as opposed to wanting more thrust and not having it.

Typically, having enough thrust to climb directly to higher cruise altitudes, instead of a step climb, offsets any reduction in fuel burn from a lower thrust to weight ratio design that must spend an initial 20-30 mins at lower altitude.

Also, at high density airports, since the A340s can't climb on the route like other traffic, they must be vectored off route in order not to impede traffic flow, which serves to increase fuel burn. Many times the daily Luft A340 out of IAH, for ex, flies on a 120 deg heading for 7-10 min during high traffic periods, instead of being able to turn directly immediately to a much more favorable 050 deg hdg. The A340-300 needs more thrust in my opinion.
 
Marcus
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RE: A340-300 Underpowered.....?

Thu Sep 05, 2002 8:15 am

If an A340 takes off using full T/O rather than Flex T/O mode, it can produce some "normal" take off displays like the pic above...
******************************

What is this flex T/O mode thing?

Kids!....we are going to the happiest place on earth...TIJUANA! signed: Krusty the Clown
 
Beefmoney
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RE: A340-300 Underpowered.....?

Sat Sep 07, 2002 1:31 pm

Marcus, "Flex" is a notch in the throttle that most Airbus pilots use for a normal takeoff. There is Full/max power and lower down on the throttle is Flex. Unless you are at a very constricting airport, you would use flex.
 
Guest

RE: A340-300 Underpowered.....?

Sat Sep 07, 2002 2:29 pm

What the A340-300 needs is to have it's wings re-designed to handle the weight of the PW2000 & RR RB211 series used on the Boeing 757 with thrust of at least 40,000lbs.

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