Why does PFPX auto-plan without considering minimum flight levels?

[Pete Dowson 1]

My PFPX is up-to-date including the last Hotfix (1.28.8).

 

I fly a 738 and use the supplied 738 default template.

 

To make sure it still worked after just applying the 1.27 to 1.28 and then 1.28.8 updates, I planned a flight from EGCC to EIDW for a flight today. I let it find the route, which it did, and it is pretty much the route I would have expected:

 

N0363F240 EKLA1Y EKLAD UY53 WAL UL10 PENIL UL70 BAGSO BAGS1K

 

with CRUISE ALTITUDE: FL240
 

But it then comes up with 5 errors, all related to wrong flight levels:

 

Altitude at 'RIGVA' (24,000 ft) below Minimum Enroute Altitude (25,000 ft)
Altitude at 'TUVDO' (24,000 ft) below Minimum Enroute Altitude (25,000 ft)
Altitude at 'PENIL' (24,000 ft) below Minimum Enroute Altitude (25,000 ft)
Altitude at 'BABRA' (24,000 ft) below Minimum Enroute Altitude (26,000 ft)
Altitude at 'GIGTO' (24,000 ft) below Minimum Enroute Altitude (26,000 ft)
 

So, if it knew about these restrictions, why did it plan for a cruise altitude of 24000 and not 26000?

 

If i go to "Advances" and change the altitude at PENIL, say, to 26000, it tries but then it needs heaps more fuel than can be accommodated. In other words it is overweight with the automatic loading i asked it to do.

 

I don't understand how a standard 738 can't manage a short flight like EGCC to EIDW with a full complement of passengers and their luggage. Ryanair must do it all the time!!

 

I provided my Schedules.txt file below. This flight is the only one planned.

 

There's no big rush for a helpful answer on this one because I am away till 25th May 2017, but i'd love there to be one when I get back, please!

 

Regards

Pete

 

 

 

 

 

Schedules.txt

[srcooke 422]

Hello Pete,

 

PFPX has planned the cruise altitude at FL240 based on the default 20% min cruise length defined in the aircraft profile.

 

It would not be aware of the cruise length until computing the flightplan.

 

Can you supply the ZFW used when overweight calculation was reached.

[Pete Dowson 1]

On 5/9/2017 at 1:03 PM, srcooke said:

PFPX has planned the cruise altitude at FL240 based on the default 20% min cruise length defined in the aircraft profile.

 

I been away on holiday -- just catching up.

 

Sorry, 20% minimum cruise length? Length in time or distance? This is a value I'm not aware of and certainly won't have adjusted.

 

Surely it should abide by airway rules and then tell me I've got to lose weight, shouldn't it? Either way, I've certainly been aboard fully loaded RyanAir flights on this route, so my fictional BA 738 should certainly make it okay. And it wasn't as loaded as RyanAir -- I use the default ProSim model which i think has first class too, not everyone crammed tight in cattle class.

 

On 5/9/2017 at 1:03 PM, srcooke said:

Can you supply the ZFW used when overweight calculation was reached.

 

I'll have to plan it again when I get a chance. Too busy with P3D4 work at present! ;-)

 

BTW I marked this thread "to follow" but never got any notification. Doesn't the facility work here?

 

Pete

 

 

[srcooke 422]

The 20% short trip cruise length apples to distance and is defined in the aircraft profile and can be edited.

 

The choice of lower/upper airways is very marginal here with the crossover at FL245/FL260.

 

For me planning with 174pax will return a route based on the lower airway at FL240. Reducing the payload or the short trip cruise length will take the route into the upper airway. It is very marginal and the final result is only found when you compute the flight.

 

Having established that FL240 is the maximum achievable enter this in the Route box MAX ALT/FL and use the find function again.

 

Not to worry about the ZFW in use Pete.

 

Notifications from the forum work here.

[Pete Dowson 1]

On 5/29/2017 at 9:01 AM, srcooke said:

The 20% short trip cruise length apples to distance and is defined in the aircraft profile and can be edited.

 

Okay, thanks. But I'm still not sure what it means. 20% of total distance as cruise ==> what action? Some trips I do barely have any cruise. Cut if I have to climb high to met minimum airway altitudes, rthen I have to.climb high.

 

On 5/29/2017 at 9:01 AM, srcooke said:

For me planning with 174pax will return a route based on the lower airway at FL240. Reducing the payload or the short trip cruise length will take the route into the upper airway. It is very marginal

 

So, something's wrong. If RyanAir can do it with a full (compressed!) load of 180 passengers, surely I can do it in the two-class (or is it three?) BA version!

 

Okay, so baggarge allowance is a little better with BA -- but not that much!

 

I'll check the baggage totals next time. Maybe TopCat or PFPX is adding other non-passenger, related bagage, which of course RyanAir does not carry.The baggage total should be passnger count x a fixed value, max.

 

On 5/29/2017 at 9:01 AM, srcooke said:

Having established that FL240 is the maximum achievable enter this in the Route box MAX ALT/FL and use the find function again.

 

To get routed on lower airways, you mean? Like those used for light aircraft?

 

Pete

 

[srcooke 422]

The lower airways are not just for light aircraft Pete, currently the upper/lower airways are been merged to encompass an available FL range.

 

Using FlightRadar historic data Ryanair typically fly this route at FL220 or FL240, the maximum planning level would be FL285 from the UK Standard Route Document.

 

If you wish to push for a higher level then the option is to reduce load or shorten the minimum cruise length set in your aircraft database. As I recall some carriers may indeed use a figure less than 20% cruise length which was discussed in the forum a long time ago, unfortunately a search does not locate it.

 

Should you shorten the cruise length you will most likely need to ensure a full CLB mode is used rather than CLB-1 or CLB-2 otherwise TOD may occur before reaching cruise.