PNR and CP calc for Palm and Pocket PC

[ITCZ]

I have been looking for a pocket device PNR and CP calculator for my palm but nothing seems to do the job I want.

I fly longer sectors (950nm-1050nm in a 146) where we spend lots of time crunching PNR's on occasions where a "tech stop" is a possibility. I figured why not put in the relevant stuff and let the Palm do the work.

I have put together a prototype calc in Excel, to output PNR and CP for normal ops, one engine inop and depressurised (all engines) situations. I plan to initially use it with Documents to Go or similar, and maybe develop a trimmed down Palm OS app later (if I ever get time). Pocket PC users could probably load it as is.

I am handing it over to Ppruners for criticism and possible improvement in layout or programming.

Inputs are sector distance, average track, fuel on board, winds at normal cruising level, return crz lvl normal ops, one inop, and depressurised (all engines), TAS and fuel flow for NO, 1INOP, DP, and required reserves (normal=30minFR+10%VR, one inop=10min+10%, DP=30minFR only). I am considering drop down lists for common sectors and different reserves for different variants. All other data is stored unless overwritten by the user.

At this stage, wind component entered by hand, not calculated -- haven't got my head around using sines and cosines of radians instead of angles in degrees (thanks go to Aviation Formulary website for formulae used, however crappily!).

If anyone wants a copy, leave a private message and I will email the Excel workbook.

Any thoughts?

Couldn't work a screenshot, but this is an rough and ready of what is on the screen

Distance to PNR and ETP
Leg: AYE-PH 245 deg 891 nm
Fuel
Left Centre Right Total
3500 kg 290 kg 3500 kg 7290 kg
Wind
Outbound 245 / 50 kt -50 kt
4E return 245 / 50 kt 50 kt
3E return 245 / 40 kt 40 kt
DP return 245 / 30 kt 30 kt
TAS Flow PNR ETP
380 kt 2000 542 nm 504 nm
350 kt 1800 595 nm 496 nm
300 kt 1920 538 nm 490 nm
Type Reserves 30 min 10 min
BAe146-200 900 kg 300 kg

[Relaxed Redback]

ITCZ.
Is there a "worst case situation".
ie is one situation DP / 2eng etc always limiting for a particular sector length ? How about off track ? Do you have any suitable airfields on the way or are you only concerned with a return to base situation?
I have found generally you can save a great deal of time if you can cover all situations with a "worst case" formula.

[Chimbu chuckles]

In my time on the Bae 146, presumably for your company, the DP case was most limiting. 3 engines are more efficient than 4:D seriously!!

I think you are complicating a simple matter inordinately by trying to get your palm pilot to do it.

I had some pretty simple formulae for each case in the Joke Jet...the calcs take all of 20 seconds!

Chuck.

[TIMMEEEE]

ITCZ - you're making life very difficult for yourself and besides, doesnt anyone carry a god-damned whiz-wheel around anymore?
Chuck out that damned Palm Pilot for starters and I'll explain a method (which you can fine tune for the 146' figures).
I can work out a PNR within seconds knowing some basic figures about your aircraft performance.

Firstly - work out the Specific Air Range (kg/nm.hr) for normal cruise which for the 146 would probably be about 5kg/nm (just a guess).

Secondly work out the SAR for a depressurised case (cruise at 10,000') at the specific fuel flow for that altitude -probably about 8kg/nm.

Add the two together - now thats 13 kg/nm total which will allow you to work out a PNR going from your present position with all 4 engines burning to a point, depressurise (most limiting case) and return depressurised at 10,000' .

Now for instance if you are doing say a Melbourne to Perth flight and you are say abeam Adelaide (100 south which makes little difference looking at the geometry of a return to ADL) and have 10,000 kg.

You need legal statutory reserves of 30 minutes fixed reserve (call it say 1240 kg) and your charts are probably worked out for an arrival overhead at 1500 ft AGL - so add manoeuvring fuel from 1500 to land (say 160 kg) plus any required WX.

Subtract your statutory reserves (in this case 1240+160 ) which is 1400 kg from your available fuel Abeam ADL (10,000) which gives you 8600kg available fuel.

Use your whiz-wheel and work out 8600 divided by 13 and that will be a rough distance to your PNR (661 nm or so).

Easy or what?
Once you know the variables it will only take seconds to work out a rough Depressurised PNR.

This is the most limiting case and if you can make a Depressurised PNR then anything else is easy.

If you want to work out any other PNR with say all engines operating dont forget the 10% fuel to be subtracted and any traffic holding to give the available fuel.

Just remember this is a rough figure (but surprisingly accurate) and takes only seconds.

Those individuals that fight over a few kg here and there and argue over a few nm are probably twits that dont think clearly or see the big picture and besides - no real methods account for the fuel required to do a 180 degree turn to go back or pilots cruising at Flight Levels would rarely know what the wind is doing at 10,000ft or whatever level they will fly depressurised!

Its academic only but important to know where you stand in terms of situational awareness.

[Chimbu chuckles]

From memory when I flew the 146 I used (FOB(in kg)- 900)/10 for a rough DP PNR before departure. After TOPC the calcs as per Timmmeee allow you to fine tune it with actual cruise outbound sgr, the cruise back sgr for 10000' will only ever be approximate because you will NEVER know the exact winds at that level. If you buffer it by say .25kg/gnm you will be safe enough...or work out a sgr into what you consider 80% probability of worst case headwinds...say -30kts or whatever is reasonable. If you get down and find only -10kts or a tailwind you will simply arrive with a little extra for mum and the kids...so what, the gauges aren't THAT accurate.

How much fuel will be used in the 180? Not much at flight idle on descent.

The DP case is the limiting case....3 eng sgr in the puff jet is better than 4 eng.

Chuck.

[ITCZ]

Timmee, Chimbu, guys, give me a break! Father knows how to pee! :rolleyes:

Pre departure, FOB*0.75 for 3E and FOB*0.7 for DP is as close as dammit. Nil wind SGR's are in the region of 5.5kg/nm normal ops, 5.3 for one inop, and 6.5 for DP. Increase/decrease by x per 1,000kg weight, etc.etc.etc.etc

I own the gadget, it is already in my pocket, I know how to program it a bit, so let me have my fun! Some guys get their jollies doing up old cars and making them go faster. They might not go faster in proportion to the midnight oil you burned on them, but you learned a thing or two while you were trying.

Now if anyone would like to answer the question as posted!!!!:cool:

Humbly

ITCZ.