Yes those rates do seem a little unbelievable. Could they be momentary peaks/troughs caused by turbulence happening at the exact same time the aircraft sends its data to the radar station?

 

Unlikely. These QF and VOZ SYD-MEL and SYD-BNE flights often reach FL410 using 767-300ER and A330 aircraft, remember these are aircraft designed for intercontinental routes of up to 12,000km being used on flights of less than 800km. They have very little fuel onboard. I've been following them on Flightradar24 often and climb rates inexcess of 3000fpm are pretty much sustained for most of the climb to altitude. Even at over FL300, climb rates are in the range of 2000-3000fpm. If I didn't see it on live data, I would've called "bulldust" on it To put it in context, these SYD-MEL flights hit FL410 before even reaching Canberra.

 

There is also a daily United Airlines 744 service between Sydney and Melbourne which tends to out-climb any of the 737's, E190's and A320's on the route!

 

For descents, I've noticed a lot of flights hit well over -3000fpm, even at lower altitudes, and seeing over -4000fpm is far from rare. Don't know how it is in other parts of the world, but here it seems to be standard practice. For some reason, domestic flights here climb to very high flight levels for the route distance... FL410 is routine for Melbourne-Sydney, Sydney-Brisbane, Melbourne-Adelaide, and I've seen FL380 often for both QF/VOZ 738 and JQ A320 aircraft on Melbourne-Launceston which is only 480km straight-line distance!

Those are all approximations unless they use some new special transponders there, that is why the rates are artificially high sometimes.

Passing 7200 feet QF520 was flying a gradient of 1 : 5. That's pretty steep for walking, cycling, driving... but not, it seems, for a big jet. I'm astonished.

 

Could that VS last?-- would the airspeed be decreasing with that sort of gradient? And... would the initial steep climb be for noise abatement? I see the plane accelerated as it climbed so I suppose the initial climb wasn't necessarily the most efficient.

 

Regards,

D

 

That's exactly what i was thinking. Surely the IAS would have been decreasing and obviously there is no way they could of continued with a climb rate over 7000+fpm over FL200 the air isn't dense enough for climb speeds like this at high alts. Makes me wonder though if these climb rate speeds are accurate? and are pilots de-rating on takeoff? Even with a lightly loaded 767 you would probably de-rate depending on the atmospheric conditions to around 60+ degrees celsious if the temperature is 15 deg C+. So therefore you would get a typical takeoff roll proabably lasting up to 30 seconds or so depending on the runway legnth etc. Then you should get a steady smooth climb rate. Would love to go on something with 10 second takeoff roles and 7000fpm climb peformance. Would be like a rocket!

I did a flight with a 737-800 to Edinburgh from Brussels south this week, and it surely climbed, even full loaded, like a rocket.

Also did some other observations about sight distance and clouds, real versus the sim, but will open another thread for it.

Descend was also steep to Edinburgh, but not on the return flight.. there might be some truth in the OP.

I did a flight with a 737-800 to Edinburgh from Brussels south this week, and it surely climbed, even full loaded, like a rocket.

Also did some other observations about sight distance and clouds, real versus the sim, but will open another thread for it.

Descend was also steep to Edinburgh, but not on the return flight.. there might be some truth in the OP.

 

That is only around 600 miles so I doubt it was fully loaded.

That is only around 600 miles so I doubt it was fully loaded.

 

correct, i ment with pax..

Glad to see this thread - you wouldn't believe how many tickets I've answered over the years complaining about the "unrealistic" V/S rates in our aircraft. They are not unrealistic - real life aircraft regularly hit 6000fpm or more. Certain aircraft are well known for being overpowered (the 757 and 767 are probably the most famous examples) and they will readily achieve these kinds of rates well into the flight levels even at substantial gross weights. Pilots aren't setting a V/S when you see this stuff - they're pitching to hold an airspeed while maintaining a constant thrust setting. The V/S doesn't matter - it's a byproduct of that particular airspeed and thrust combination along with the atmospheric conditions.

 

It's important to remember that what people feel is the rate of change in a climb or descent, not the raw vertical speed value. If you make a sudden change from 0 to 6000 FPM, you're going to pull a lot of positive Gs and it'll be uncomfortable. If it's a gradual onset over the course of the initial climb however, you're not going to feel it very much, if at all. One cool analogy - you're currently traveling through space at around 108,000km per hour as the earth orbits the sun. No one feels this because it's a constant rate of motion. Same idea with the V/S - as long as its constant and not rapidly changing it doesn't matter what the rate is, it won't feel uncomfortable.

 

Airspeed plays a big role here too, especially with the values you'll see in an initial descent - the airplane is at cruise speed when it starts down and that means you need only a shallow descent angle to create relatively high V/S. Check it out in the NGX using the DES page - you can actually see the current angle there - compare it to that same angle down lower at a slower airspeed. There's a big difference.

High climb rates are quite typical at lower altitudes. Because of air density. In my area we have the Alps which for obvious reasons have to be crossed at quite high altitudes! For example at LIMF Torino Caselle there is no noise abatement on rwy 36 so airlines like BA en route to Gatwick can literally power up to be at their cruising altitudes by the time they pass Monte Bianco.

The same goes for the descent. Crossing from the Alps to the Pianura if you are landing at Torino or Levaldigi. It's turn the a/c into a flying brick time.

Even old a/c are capable of high climb rates. The VC10(designed for hot and high performance) is a perfect example.

On a low weight Concorde, it wasn't called climb rate, but zoom rate. ^_^

I noticed during ToD with various payware aircraft is the tendency for aircraft to descend close to 4000fpm initially and then reduce to a more reasonable value (~2500fpm) throughout the rest of the descent This happens a lot with idle descents with a high FMS/VNAV computed descent airspeed/mach.

I am not real world pilot, but I think it is pretty unbelievable that a pilot would push his airliner full of people to > ~4000 fpm vertical. Is this where your ears start to fall apart and red hot metal spikes are inserted into your head? Maybe capt. Ronan can chime in? Of course if you are ferrying the A/C and it's empty besides the blokes in the cockpit, it's another story

 

By the way, can anyone tell what are limits to the cabin vertical speed in normal operations? I am inclined to think that it is somehow connected the max flow capacity of the outflow valve but i easily can be wrong.

 

Oh, and flightradar24 and other such websites pull data every 8 seconds or so and everything between two polls is an interpolation in order to have animated aircraft icons. it is an option - you can turn it off or on. Also, the ADS-B does not contain vertical speed data. Please refer to http://planefinder.net/about/ads-b-how-planefinder-works/

The cabin pressure doesn't change at that rate, so the punters aren't going to notice.

Maybe Capt. Rónán can chime in?

The rates given are for the VS of the aircraft, and not the Cabin, it's the cabin VS that'll make your ears pop. ^_^

 

Regards,

Ró.

The rates given are for the VS of the aircraft, and not the Cabin, it's the cabin VS that'll make your ears pop. ^_^

 

Regards,

Ró.

 

Yes sir, I am aware of the difference between those. I am not sure how are they connected (if any). What on those climb rates? Is it normal to exceed, let's say 3500 fpm on a climb/descent on full A/C under normal procedures?

Yes sir, I am aware of the difference between those. I am not sure how are they connected (if any). What on those climb rates? Is it normal to exceed, let's say 3500 fpm on a climb/descent on full A/C under normal procedures?

They're not connected - ish, within reason. It's all very dependent on conditions as to whether you can achieve those rates or not. If by full you mean full PAX, full Cargo, full Fuel, then no, you're not very likely to see rates of climb. With say full pax, full cargo but only enough fuel for a one hour hop in an A330, then you'd certainly be more than capable of getting rates like that if you tried...

 

Regards,

Ró.