Unnecesary/improper/excessive climbs and descents when flying routes that are not directly east/west

[DLRK 2]

When I try to plan a flight that doesn't consistently proceed in a east or westerly direction(for example, a flight from the north to south US on airways), any change direction tends to result in a climb or descent in an apparently misguided effort to comply with NEODD/SWEVEN.

[FlightSimSoft.com 283]

When I try to plan a flight that doesn't consistently proceed in a east or westerly direction(for example, a flight from the north to south US on airways), any change direction tends to result in a climb or descent in an apparently misguided effort to comply with NEODD/SWEVEN.

Difficult to answer without knowing the route...

[DLRK 2]

True, I apologize for that.

CRL DCT APE J83 SPA J53 CRG J45 OMN HILEY4

[FlightSimSoft.com 283]

That's what I get with a 737:

N0437F350 DCT CRL DCT APE/N0439F360 J83 SPA J53 DUNKN/N0440F370 J53 CRG J45 OMN HILEY4

Two steps. Seems okay.

[DLRK 2]

Christian,

Thanks for the quick reply. Unfortunately, that route is improper since it starts out with an even altitude, which would be appropriate for a westward flight and changes to odd altitude which is appropriate for an eastward flight. Since the flight is an eastbound flight, both altitudes should be odd.

[DLRK 2]

An autogenerated route actually winds up including descents in the middle of the flightplan.

[FlightSimSoft.com 283]

Christian,

Thanks for the quick reply. Unfortunately, that route is improper since it starts out with an even altitude, which would be appropriate for a westward flight and changes to odd altitude which is appropriate for an eastward flight. Since the flight is an eastbound flight, both altitudes should be odd.

• The route starts with an odd Level (350) in easterly direction
• After APE the route continues on magnetic track 181, which is in 'westerly' direction, givin even Levels
• At DUNKN the route turns to an easterly track again, giving an ODD Level

So I would say the result is correct...

[DLRK 2]

Christian,

The U.S. NEODD SWEVEN rule is based on the direction of the destination, not the airway. This can be seen in that airliners will commonly fly routes that occasionally deviate to the east or west, but will maintain an even or odd altitude depending on the direction of their destination.

[FlightSimSoft.com 283]

Christian,

The U.S. NEODD SWEVEN rule is based on the direction of the destination, not the airway. This can be seen in that airliners will commonly fly routes that occasionally deviate to the east or west, but will maintain an even or odd altitude depending on the direction of their destination.

Can't really agree to that. Maybe there is some kind of exception in the US I've never heard of.

The airways in your example are marked with the cruise table 'SA' which basicly means ODD Levels between a magnetic track of 000° and 179° and EVEN Levels between 180° and 359°.

[DLRK 2]

Christian,

For example, please take a look a this Flightaware track. http://flightaware.com/live/flight/DAL1829/history/20130830/1235Z/KDTW/KMIA

This shows a Delta flight steadily planned and flown at FL370, despite flying a similar route to the one shown here. I would very much appreciate if you would check with someone experience with US operations, and if appropriate, issue an update. For now I will avoid using the OPT function on affected routes.

[wilme861 1]

The NEODD SWEVEN is used for general flight planning purposes. The reality is the altitude you need to be at will be determined by ATC. Controllers determine the altitude to use based on either a SOP, LOA or just the general NEODD SWEVEN rule if the other two don't apply. It doesn't matter where your destination is when it comes to this. If you are flying a 001 heading, you need to be ODD unless a SOP or LOA states otherwise.

What PFPX does is correct as there is no way to know all the SOPs and LOAs used by controllers to guarantee you are at the correct altitude the entire flight. For example, who would file an ODD altitude from MYNN to KATL? However, going from ZMA to ZJX requires an ODD altitude (at least real world) but everyone will file an EVEN altitude, which is correct since the first few controllers need you at that altitude before you are climbed to an ODD one prior to the boundary.

[robb_speed 6]

http://flightaware.com/live/flight/AAL837/history/20130830/1325Z/KJFK/MTPP

The above link may not work if someone searches this post 10 years from now :-)

Flightaware shows the flight planned at FL350. However, you see the route initially is flown to the SW. Looking at the track log, you will see the flight is at FL340 for that phase. Later on, closer to the destination, you see the track going to the SW again. If you look at the track log closely, you see the flight going back to and cruising at FL340 before beginning the descent.

This is one example and I'm sure you can find a flight that disproves the rules, as your example does. As a previous poster noted, the FL you fly at is ultimately decided by ATC. What flightaware shows as filed altitude doesn't really matter.

Pfpx in this regard does its job appropriately. (The users who still have trouble with CFMU validation may not agree with me) ;-)

Rob

Sent from my iPad using Tapatalk HD

[DLRK 2]

Rob,

Thanks for the info! Guess I was mistaken.

By the way, what exactly is CFMU validation? Is it a European thing?

[robb_speed 6]

By the way, what exactly is CFMU validation? Is it a European thing?

Yes it's a Euro 'flow control' sort of thing. A sticky was made of it in these forums in regards to how to fix a fp that doesn't pass validation. Cheers to the forum member who wrote it up. :-)

Rob

Sent from my iPad using Tapatalk HD