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Start Low, Climb During Cruise, North Atlantic?  
User currently offlineJulianuk From United Kingdom, joined Apr 2006, 105 posts, RR: 0
Posted (8 years 1 month 3 weeks 10 hours ago) and read 4945 times:

Doing the North Atlantic tracks US to Europe (which are the busiest airways I think) how are climbs co-ordinated - as you burn off fuel my Airbus manual says that "as weight reduces the opitmum altitude will increase and there are number of different ways of doing a climb pattern throughout the cruise"

Well for the North Atlantic tracks what do you have to do - let them know before entering the track when you want to climb or can you do it enroute - I imagine this would cause a lot of work for Air Traffic as FMS systems would be advising a climb would be beneficial?

[Edited 2006-07-02 16:43:19]

12 replies: All unread, jump to last
 
User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 1, posted (8 years 1 month 3 weeks 10 hours ago) and read 4929 times:

Going from North America to Europe is not so much of a problem. The NAT structure doesn't start until after several hours of cruise flight, even from New York or Montreal. Most people don't realize just how far east the Labrador or Newfoundland coast is. From New York to Gander, a coasting out point is about the same distance as New York to New Orleans. It is a long time at cruise, burning off fuel. Most step climbs are done by coast out.

Returning from Europe to North America presents a bit more of a problem. If one were going from London, or even worse, Shannon, to, say, Los Angeles one would probably step climb after coasting in over Canada. The track structure typically starts at about 15° West, or just off the coast of Ireland.

It is sometimes possible to get a climb while on the tracks, but not always.
The guys who dispatch these routes are pretty smart and usually have this stuff worked out well in advance.



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineJulianUK From United Kingdom, joined Apr 2006, 105 posts, RR: 0
Reply 2, posted (8 years 1 month 3 weeks 9 hours ago) and read 4921 times:

Thanks Slam, on a step climb have you got the information sorted before leaving base so you know exactly your best points to climb or is the point at which you want to climb changing all the time depending on winds and fuel burn en route?

User currently offlineFlyMatt2Bermud From United States of America, joined Jan 2006, 563 posts, RR: 7
Reply 3, posted (8 years 1 month 3 weeks 9 hours ago) and read 4915 times:

Quoting JulianUK (Reply 2):
On a step climb have you got the information sorted before leaving base so you know exactly your best points to climb or is the point at which you want to climb changing all the time depending on winds and fuel burn en route?

The temperature aloft forecasts are usually within a few degrees. You might be surprised to know that ISA +10 to 15C is seen frequently in the North Atlantic.

Our computerized flight plans will show us where to anticipate being able to step climb. Fortunately most tracks they are the same direction every thousand feet so there is more room to allow you to climb if they permit it. However, always know what will happen in case all you hear back is "Unable, climb due traffic, maintain present flight level" until you get to Coast In.

The flight plan transmitted also indicates our highest flight levels so ATC can plan accordingly. This is done more to assist ATC planning than our capabilities.



"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward" Leonardo Da Vinci
User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 4, posted (8 years 1 month 3 weeks 9 hours ago) and read 4906 times:

Quoting JulianUK (Reply 2):
on a step climb have you got the information sorted before leaving base so you know exactly your best points to climb or is the point at which you want to climb changing all the time depending on winds and fuel burn en route?

As reply #3 implies, the winds (and temperature) aloft forecasts are pretty accurate and I rarely see much deviation from them on any given flight. Biggest wildcard might be actual route flown from takeoff to coast-out, which necessitates a recomputing of the points.

The crew has always had the option and capability of picking their own points to request a step climb. Either the FMC or our charts can tell us optimum altitudes for our weight and ambient temperature.



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineFlyMatt2Bermud From United States of America, joined Jan 2006, 563 posts, RR: 7
Reply 5, posted (8 years 1 month 2 weeks 5 days 19 hours ago) and read 4632 times:

Quoting SlamClick (Reply 4):
Biggest wildcard might be actual route flown

I hate it when the flight planners do something stupid like filing your route to cross the NAT Tracks. We get these flight plans from time to time but our clearance is usually on a NAT Track. So take all those neat little projections and throw them down the shoot. We had to land a Shannon unexpectedly because the realistic route took us 45 minutes more than the flight plan. It would not have been a problem except our destination was forecasting low IFR so we had to have alternate plus fuel.



"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward" Leonardo Da Vinci
User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 6, posted (8 years 1 month 2 weeks 5 days 9 hours ago) and read 4583 times:

Quoting FlyMatt2Bermud (Reply 5):
the flight planners do something stupid like

The only dumb mistake I've ever had happen was on a flight to Rome. Our route was something like
Gander to 49N 50W to 49N 40W to 50N 30W etc.

Well they fed it to the computer as
Gander- 49N 50W - 49N 60W - 50N 30W.

So from Gander the flight plan backtracked then reversed again, adding 770 unnecessary nautical miles to the trip. That was how it was planned and how it was filed. Clearly the intent, verified by the routing statement of the NAT Track Message was a straight line across. Worse, it figured time and fuel as if we were actually going to fly that dogleg route.

Well, during the preflight planning session, as I'm drawing up the North Atlantic plotting chart it was not hard to see the mistake. Drawn on paper it is a big lightning bolt, where on the flight plan is was just a number stream. Anyway, it was too late, the plane had already been fueled for this route.

So it was the one time I tankered fuel across the Atlantic to Rome.



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineJulianuk From United Kingdom, joined Apr 2006, 105 posts, RR: 0
Reply 7, posted (8 years 1 month 2 weeks 5 days 9 hours ago) and read 4576 times:

Actually while I have you Mr Slam, what's the deal with bad weather on the NATS track? That must really upset things if there is a big CB in the way -how do they co-ordinate everyone behind you ensuring they don't catch up too quickly if you have to go around the big thunderstorm?

J


User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 8, posted (8 years 1 month 2 weeks 5 days 6 hours ago) and read 4534 times:

Well, I can only speak from my limited experience and met knowledge but...

A single cell may disrupt one individual track, but there are never fewer than five of them available. Some may require 180 minute and so, cause problems. If you cannot use any of the established tracks then there is always random-nav to the north or south of them.

Typically, thunderstorms in Arctic or subArctic regions do not build to the heights we see in tropical or subtropical locales. While I still want no part of a CB a mere 25000' high, I might not worry so much overflying it at FL370. LINES of thunderstorms are another thing I've never seen over the north Atlantic. I'd like to hear from a pilot more experienced there than I am on that, though.

Lines of thunderstorms seem to require a specific phenomenon to be a common occurrence. A good example is the "Marfa line" from southwest Texas up across Oklahoma and Kansas. We commonly see cooler, dry air with a large temperature/dewpoint spread on the northwest side of this line and hot moist up from the Gulf of Mexico on the southeast side. This is a severe-weather factory, and one of the reasons for 'tornado alley.'

I'm not aware of any persistent condition over the north Atlantic that would produce such effects.

So, a cell here and there - switch tracks, go random nav or overfly. Lots of cells, it could get messy.



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineFlyMatt2Bermud From United States of America, joined Jan 2006, 563 posts, RR: 7
Reply 9, posted (8 years 1 month 2 weeks 5 days ago) and read 4472 times:

Quoting Julianuk (Reply 7):
What's the deal with bad weather on the NATS track? That must really upset things if there is a big CB in the way -how do they co-ordinate everyone behind you ensuring they don't catch up too quickly if you have to go around the big thunderstorm?

Deviations for TRW's along the NAT TRACK require coordination and planning. If you are unable to obtain a deviation clearance some area's permit the pilot to deviate without a clearance as necessary however we must broadcast our intentions on 123.45. To ensure separation the rules require us to notify ATC anytime our ETA over the next fix is off more than 3 minutes. Therefore it is important that you have reasonable current wind & temp aloft forecasts. The best method for deviations is through the pilot to pilot freq 123.45. The aircraft on your track and at your altitude 100 miles ahead can really assist in describing turbulence and what to expect. Deviations are normally requested in increments of 20 miles North or South of course usually up to 60 miles depending upon what the controling facility will allow.



"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward" Leonardo Da Vinci
User currently offlineFlyMatt2Bermud From United States of America, joined Jan 2006, 563 posts, RR: 7
Reply 10, posted (8 years 1 month 2 weeks 4 days 19 hours ago) and read 4422 times:

Quoting FlyMatt2Bermud (Reply 9):
The best method for deviations is through the pilot to pilot freq 123.45.

What I meant to imply is communicating severe flight conditions and deviations among crews operating in a region can assist you to obtain your deviation authorization from the controlling facility in time to avoid the weather. It normally takes 10 to 15 minutes (or more) for ARINC to get back to you with authorization from ATC to deviate. In that amount of time you've travelled nearly 100 nautical miles. Your weather radar & storm scope might not be good enough (by themselves) to help you determine whether and which direction you want to deviate when you're looking at weather 100+ out and especially if there is weather between you that may interfere with the returns further up the road.



"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward" Leonardo Da Vinci
User currently offlineFxra From United States of America, joined Jul 1999, 706 posts, RR: 2
Reply 11, posted (8 years 1 month 1 week 4 days ago) and read 4066 times:

As a dispatcher with planes crisscrossing the Atlantic daily, i will say in my experience you rarely get altitude changes crossing the North Atlantic on a random route. Usually I'll plan the flight at a consistant altitude across the pond and then in remarks area or during a crew brief tell the capt that the computer says you will get better burns if you climb at 30W. Occasionally we'll see them climb. I'd say about 90% of the time its a consistant flight level. As far as I know once you're on the NAT track your are cleared to cross at a specific FLight level and your stuck there unless you need higher for turbulence or ATC needs u higher for traffic.

Working for a non sked carrier we often go against the traks, flying westbound during the normal eastbound flow. You have 2 choices, fly around the tracks or under them. I've had to plan flight say from KATL-EDDF starting at FL350 to somwhere near Gander then drop to FL290 for the atlantic crossing and back up over Ireland. It looks rediculous on paper, but its cheaper than going around. Again i'll tell crew they are clear of the track sstructures at say 40W and ask for higher...

later



Visualize Whirled Peas
User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 12, posted (8 years 1 month 1 week 4 days ago) and read 4059 times:

Quoting Fxra (Reply 11):
As a dispatcher with planes crisscrossing the Atlantic daily, i will say in my experience you rarely get altitude changes crossing the North Atlantic on a random route.

I'll second that. We rarely will see a climb during the N.A. xing. In fact it would be more common to see a descent for the xing since we usually see a R.R. and will often be higher than the cleared xing altitude. Dispatch knows this and will have planned the burn as such.


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