HP 15CE Aviation Pac

[Geoff Quickfall]

I now have an HP 15 CE of which lots has been posted at this site.

The HP 15CE has a usb cable which enables one to upload and download calculator states into the 15CE.

This works as a backup of the full expanded memory available on this model or to exchange Pacs, which are in development, ala the 65, 67, 41C et al.

In this case, I was asked to produce an aviation pac, which I did. However, I made it a little more quirky. After 45 years of flying and using various HPs on the flight deck:

25C 19C, 29C, 34C, 65C, 67C, 71B, 41CX / CL, 48GX, 42S, various Swiss Micros and many others,

I developed my own set of programs, mainly used on my 41CX and 41CL.

With that in mind, I have created an Aviation Pac with some of the standard programs and some that applied to my airline, long haul operations which will not be found elsewhere but are extremely applicable, IMHO ?

I include a link to a dropbox folder. In it are two Pacs files. One is the Aviation pac which can be loaded into your 15CE via the cable and comes with a full manual. The manual includes the formulae, explanations and examples plus the full ~500 lines of code.

A second file is unique unto itself. It is a Break Schedule program which can apply to any transportation sector to relieve operational fatigue. A version of this was written by me for the 41CX back in 1988 and I have rewritten it for the 15C.

The Break Schedule is standalone as it uses 10 subroutines. This precludes me from adding it to the Aviation Pac as that would limit the direct access GSB routine selection. The full explanation of this routine is also found in the Aviation Pac manual.

I have included photos of the manual as a teaser. I do hope you find this useful, it did take awhile to write, correct and etc. A caveat, I can program in many languages but I am not proficient in any. Please excuse the inelegance of the programming style, suffice to say, it all works and the answers the routines produce are correct.

The answers produced by these routines were checked on other devices and on the internet when the were comparable site calculators.

José González Divasson at thecalculatorstore.com is in the process of creating a rubber overlay similar to the HP 16C overlay currently available at his site for the HP 15CE. You can also purchase the USB cable there, after all, who want to keep coding in a 500 line code????

Geoff Quickfall.

The drop box link:

https://www.dropbox.com/scl/fo/ibsvw2bf1...i7j1s&dl=0

Please let me know if you actually have access. I set it up for viewing and downloading but NOT EDITING ?

Here are some teaser photos of the manual and some of the routines. If you are able to attend the HHC2024 it will be included in the thumbdrives.
























__________________________________________________________


For those that don’t know:

The HP 15CE is the newest version of the HP 15C. It has the capability to emulate a full 16C or a 15C with increased memory.


To see more, visit the thecalculatorstore.com

[Maximilian Hohmann]

Hello Geoff!

(08-20-2024 10:24 PM)Geoff Quickfall Wrote:  The drop box link:
...
Please let me know if you actually have access.

Yes, I do have access. I downloaded everyting and am tempted to flash one of my two HP-15CEs with your software (or buy a third one for that purpose...) so that I can add it to my collection of navigation calculators.
I really appreciate the effort you put into the manual. Unfortunately I have no use for it at work because ForeFlight (https://foreflight.com/europe/ - there are similar products from other companies, but my employer chose this one) put an end to every other aviation calculator, chart, spreadsheet, briefing package and whatever else one used in the past to plan, prepare and conduct and record a flight. 2024 is the year we live in :-)

In "my" aircraft I still keep a Ti-85 that I bought on eBay for one Euro a long time ago and on which I have only two programs, both of which could be added to your package:
The first one is called "Delta ISA" and calculates the difference to the conditions in the standard atmoshere using the limited data that our avionics provide: Fight level, ram air temperature and Mach number. It is useful for explaining why the performance of the aircraft is better or worse than on other days. High temperatures (positive values for delta ISA) result in reduced performance, i.e. higher fuel burn, lower climb rate and less speed. On days like that it might be a good choice to cruise at a lower flight level - if available.
The second one is called "Fuel" and does the trivial conversion of fuel units in lb, as indicated on our instruments and in our flight planning to litres as required for refuellers in Europe. I have memorised the conversion factor and can do the calculation without a calculator, but for peace of mind I prefer to use my little program. There is no more stupid mistake in aviation than to under or overfuel...

Regards
Max

[KeithB]

"There is no more stupid mistake in aviation than to under or overfuel..."

I was touring the DTRA museum* on Kirtland AFB and the old timer giving the tour mentioned a time when he came across a nuclear weapon on the flightline filled with Jet fuel.
I am not sure if this is an under or over-fuel situation...8^)






* https://www.dtra.mil/DTRA-Mission/Refere...ns-School/

[Johnh]

Thanks for posting. It's fascinating to see some of the calculations that are important in a field very different to my own. And the documentation is an object lesson in how to present it!

[rprosperi]

(08-21-2024 07:39 PM)KeithB Wrote:  I was touring the DTRA museum* on Kirtland AFB and the old timer giving the tour mentioned a time when he came across a nuclear weapon on the flightline filled with Jet fuel.
I am not sure if this is an under or over-fuel situation...8^)

Can you just imagine the reports and paperwork that this led to?... and when they found someone stupid enough to have done this, I'm pretty sure he/she was removed from the maintenance/fuel staff.

[KeithB]

IISTR that they never did find out who did it. I think this was about the time of Operation Chrome Dome. Anything that happened on the ground was not considered a "Broken Arrow" and listed as no harm/no foul.

[Geoff Quickfall]

Hi Max,

When I started with the airline in 88 there was nothing but nomographs. A small 2K on board computer called a PMC (performance management computer) and of course the INS with a whopping RAM for 9 waypoints.

So automating calculations and creating flight plans on the go with the 41CX was the way to go.

Of course the 67, 77 and 87 all have flight management computers but still, QRH landing performance on the 67 was still nomographs.

77 and 87 have the onboard electronic library which had a calculator (basic) and did the calculations for T/O and LDG but it was nice to check against an independent source.

Confirming on board, that my TAS, IAS, MACH, Optimum altitude routines where all comparable to the on board systems was great.

But the requirement for waypoint passage with track and distance fell by the wayside when a reroute ocurred. So out comes whatever programmable HP I had with me and one independent confirmation was then completed.

Even at retirement on the 787 I was mentally calculating the descent start point and the descent checks every 5000 feet to ensure the computer had not lost the plot.

Cheers, Geoff

[Thomas Klemm]

(08-20-2024 10:24 PM)Geoff Quickfall Wrote:  GREAT CIRCLE

Was this program inspired by this post?

---

To run it in this simulator:

Code:

   001 { 42 21 11 } f LBL A
   002 { 42  7  4 } f FIX 4
   003 {    43  2 } g ->H
   004 {    44  3 } STO 3
   005 {       33 } Rv
   006 {    43  2 } g ->H
   007 {    44  2 } STO 2
   008 {       33 } Rv
   009 {    43  2 } g ->H
   010 {    44  1 } STO 1
   011 {       33 } Rv
   012 {    43  2 } g ->H
   013 {    44  0 } STO 0
   014 {    43 32 } g RTN
   015 { 42 21 12 } f LBL B
   016 { 42  7  3 } f FIX 3
   017 {    45  2 } RCL 2
   018 {        1 } 1
   019 {    42  1 } f ->R
   020 {    45  1 } RCL 1
   021 {    45  3 } RCL 3
   022 {       30 } -
   023 {       34 } X<=>Y
   024 {    42  1 } f ->R
   025 {       34 } X<=>Y
   026 {       36 } ENTER
   027 {       33 } Rv
   028 {       33 } Rv
   029 {    43  1 } g ->P
   030 {       34 } X<=>Y
   031 {    45  0 } RCL 0
   032 {       30 } -
   033 {       34 } X<=>Y
   034 {    42  1 } f ->R
   035 {       33 } Rv
   036 {       34 } X<=>Y
   037 {       33 } Rv
   038 {    43  1 } g ->P
   039 {       34 } X<=>Y
   040 { 43 30  2 } g TEST 2
   041 {    32 .0 } GSB 10
   042 {    44  9 } STO 9
   043 {       33 } Rv
   044 {       34 } X<=>Y
   045 {    43  1 } g ->P
   046 {       34 } X<=>Y
   047 {        6 } 6
   048 {        0 } 0
   049 {       20 } *
   050 {    43 44 } g INT
   051 {    45  9 } RCL 9
   052 {    43 44 } g INT
   053 {       26 } EEX
   054 {        3 } 3
   055 {       10 } /
   056 {       40 } +
   057 {       31 } R/S
   058 {    45  2 } RCL 2
   059 {    44  0 } STO 0
   060 {    45  3 } RCL 3
   061 {    44  1 } STO 1
   062 {    43 35 } g CLx
   063 {       31 } R/S
   064 {    43  2 } g ->H
   065 {    44  3 } STO 3
   066 {       33 } Rv
   067 {    43  2 } g ->H
   068 {    44  2 } STO 2
   069 {    22 12 } GTO B
   070 { 42 21 .0 } f LBL 10
   071 {        3 } 3
   072 {        6 } 6
   073 {        0 } 0
   074 {       40 } +
   075 {    43 32 } g RTN

[Geoff Quickfall]

Well no, not that one as I wrote this program for my HP25 back in 79. I have many reference books on great circle distance and track and have created both the polar / rectangular routine as well as the sin / cos routines.

The books are in storage so I will have to dig them up. But the routines are created by me from standard math or navigation book formula.

Geoff

But thanks for pointing me at the post, very interesting.

Cheers

[Geoff Quickfall]

For the users not that familiar with the 15CE or 15C in general.

The calculator comes with factory set memory allocation. This allocation can be altered with the DIM (i) command.

The set of routines listed above use the expanded version of the 15CE to the max with the factory allocation. To increase the memory for programs you must use the DIM coomand.

My routines only use 10 registers so I set the DIM to:

10
DIM
(i)

Which allowed me to add some more code to the Great Circle routine.






(see 15CE manual to or the posts pinned at the top of the HPMuseum forum section by Gene.)

[Thomas Klemm]

(08-22-2024 04:03 AM)Geoff Quickfall Wrote:  Well no, not that one as I wrote this program for my HP25 back in 79. I have many reference books on great circle distance and track and have created both the polar / rectangular routine as well as the sin / cos routines.

The books are in storage so I will have to dig them up. But the routines are created by me from standard math or navigation book formula.

Usually the classic formulas you mentioned in your documentation are used.
So I was a bit surprised that the same idea is used in the program: rotate the coordinate system so that the z-axis passes exactly through the first waypoint.

If you ever feel like publishing your sources, that would be very interesting to me.

---

In the meantime I was able to shorten your original program by a few bytes:

Code:

   001 { 42 21 11 } f LBL A     ; LOAD WAYPOINTS
   002 { 42  7  4 } f FIX 4     ; λ_2 φ_2 λ_1 φ_1
   003 {    43  2 } g ->H       ; λ_2 φ_2 λ_1 φ_1
   004 {    44  3 } STO 3       ; λ_2 φ_2 λ_1 φ_1
   005 {       33 } Rv          ; φ_2 λ_1 φ_1
   006 {    43  2 } g ->H       ; φ_2 λ_1 φ_1
   007 {    44  2 } STO 2       ; φ_2 λ_1 φ_1
   008 {       33 } Rv          ; λ_1 φ_1
   009 {    43  2 } g ->H       ; λ_1 φ_1
   010 {    44  1 } STO 1       ; λ_1 φ_1
   011 {       33 } Rv          ; φ_1
   012 {    43  2 } g ->H       ; φ_1
   013 {    44  0 } STO 0       ; φ_1
   014 {    43 32 } g RTN       ; 
   015 { 42 21 12 } f LBL B     ; GREAT CIRCLE
   016 { 42  7  3 } f FIX 3     ; 
   017 {    45  2 } RCL 2       ; φ_2
   018 {        1 } 1           ; 1 φ_2
   019 {    42  1 } f ->R       ; r=sin(c) w=cos(c)
   020 {    45  1 } RCL 1       ; λ_1 r w
   021 {    45  3 } RCL 3       ; λ_2 λ_1 r w
   022 {       30 } -           ; A=λ_1-λ_2 r w w
   023 {       34 } X<=>Y       ; r A w w
   024 {    42  1 } f ->R       ; u=r*cos(A) v=r*sin(A) w w
   025 {    43 33 } g R^        ; w u v w
   026 {    43  1 } g ->P       ; r φ v w
   027 {       34 } X<=>Y       ; φ r v w
   028 {    45  0 } RCL 0       ; φ_1 φ r v
   029 {       40 } +           ; φ+φ_1 r v v
   030 {       34 } X<=>Y       ; r φ+φ_1 v v
   031 {    42  1 } f ->R       ; x z y y
   032 {       34 } X<=>Y       ; z x y y
   033 {       33 } Rv          ; x y y z
   034 {    43  1 } g ->P       ; r t=C y z
   035 {    43 33 } g R^        ; z r t
   036 {    43  1 } g ->P       ; 1 a t
   037 {       33 } Rv          ; a t
   038 {        6 } 6           ; 6 a t
   039 {        0 } 0           ; 60 a t
   040 {       20 } *           ; d=60a t
   041 {    43 44 } g INT       ; d t
   042 {       34 } X<=>Y       ; t d
   043 { 43 30  2 } g TEST 2    ; t<0?
   044 {    32 .0 } GSB 10      ; reverse heading
   045 {    43 44 } g INT       ; t d
   046 {       26 } EEX         ; 1 t d
   047 {        3 } 3           ; 1e3 t d
   048 {       10 } /           ; .t d
   049 {       40 } +           ; d.t
   050 {       31 } R/S         ; 
   051 {    45  2 } RCL 2       ; 
   052 {    44  0 } STO 0       ; 
   053 {    45  3 } RCL 3       ; 
   054 {    44  1 } STO 1       ; 
   055 {    43 35 } g CLx       ; 
   056 {       31 } R/S         ; 
   057 {    43  2 } g ->H       ; 
   058 {    44  3 } STO 3       ; 
   059 {       33 } Rv          ; 
   060 {    43  2 } g ->H       ; 
   061 {    44  2 } STO 2       ; 
   062 {    22 12 } GTO B       ; 
   063 { 42 21 .0 } f LBL 10    ; 
   064 {        3 } 3           ; 
   065 {        6 } 6           ; 
   066 {        0 } 0           ; 
   067 {       40 } +           ; 
   068 {    43 32 } g RTN       ;

You may notice that register 9 is not used anymore.
For the rotation by \(\varphi_1\) it doesn't really matter which coordinates are in the x- and y-registers. But depending on the choice the value has to be added or subtracted.

[Geoff Quickfall]

I will dig it up, it is storage after renovating the cave! I seem to remember that it was a navigation book using programable calculators.

This particular program using the polar / rectangular functions was for the HP 25. It used the same amount of memory as the standard sin / cos routine but was an interesting math solution.

On the 41C I would put a test in to determine if the longitude of point a was equal to the longitude of point b, therefore due north or south, then a second subroutine to determine if point a longitude was > than point b for direction of flight.

Another to determine if you were traversing through a pole.

Which raises an interesting point on the GPS navigation used on the Flight Management Computers that Boeing used. I am sure this applies to Airbus FMAs. The flight cannot proceed within 90 nautical miles of true north or true south.

Having flown over the north pole a few times it was interesting to see the dogleg around the north pole on the flight plan. This occurred with GPS, INS and IRS navigation from latitude / longitude waypoints.

Cheers

[Thomas Klemm]

(08-24-2024 07:23 PM)Geoff Quickfall Wrote:  On the 41C I would put a test in to determine if the longitude of point a was equal to the longitude of point b, therefore due north or south, then a second subroutine to determine if point a longitude was > than point b for direction of flight.

Another to determine if you were traversing through a pole.

This is the huge advantage of using the polar / rectangular functions.
They just work without handling special cases.

Examples

Over the north pole:

A: (60, 0)
B: (30, 180)

5400.000

To the south:

A: (60, 0)
B: (30, 0)

1800.180

---

Quote:east and south co-ordinates are entered as negative values.

Just out of curiosity: Is this an American convention or common practice in aviation?

[Maximilian Hohmann]

Hello!

(08-25-2024 08:22 AM)Thomas Klemm Wrote:  Just out of curiosity: Is this an American convention or common practice in aviation?

In western aviation everything follows American conventions (this is why, for example, we still measure altitude in feet even in places where this unit has been abolished 200 years ago) so it is rather a general convention. When doing calculations, there is an aide-memoire: "East is least" which means that east is associated with the negative sign.

But: Wherever coordinates can be entered into onboard navigation devices there are no signs. One always uses the letters "E" "W" "N" and "S" which can either be entered through an alphanumeric keyboard (e.g. on an FMS) or by fiddling with rotary knobs. This is the only safe way.

And but but: In commercial aviation (private flyers can do what they want as long as they don't violate any airspaces) we are not supposed to enter coordinates ourselves. Since decades, navigation equipment comes with databases that contain all the required waypoints. These databases are extensively quality controlled and are updated in regular intervals through approved and documented procedures. If a waypoint is not in the database you don't fly there. That simple.

Regards
Max

[Geoff Quickfall]

Hi Max and others!

To further extend Max’s explanation:

1). On the 41CX and 71B I established a routine to check for alpha N, S, E and W. This would then assign a -ve or +ve value for the calculation in the routine. Yes, co-ordinates on the aircraft are entered as a +ve number with the alpha value attached to the front:

On Boeings and the DC10 INS N45 15.6 with seconds as a decimal.

2). There are defined (named) waypoints, those that are part of a programmed data base and undefined waypoints. Overseas operations differ from land based operations in that the waypoints that are not defined (undefined or unnamed) waypoints. These waypoints are not found in the data base and are entered by latitude and longitude. These occur on the North Pacific and North Atlantic and are based on the least time track (shortest fuel and time track),

Procedures for checking the undefined waypoints after the computer (FMC) is loaded require a total distance check (last page of the FMC), ETA for total route (winds are also inserted) and a distance and track check between each waypoint and compared to the printed flight plan created by a mainframe (for Air Canada we used Lufthansa flight planning).

Further, a reroute on the North Atlantic was not uncommon when entering Scottish Airspace north of the published tracks (Vancouver London/Frankfurt/Paris/Rome/ Europe) as our timing for entry was at the same time as the new published tracks for the next 24 hours were published and in use.

This is where the Distance.Track routine was used as it supplied the distance.track check independently of the FMC and since the reroute was not on a flight plan, there was no independent printed flight plan to compare too.

As stated, the distancd.track check MUST be done at the gate or in flight to confirm that the waypoint latitude and longitude were input correctly.

Thomas!

Yes, that is the reason!!! The formula does however, require that E and S be entered as negatives for the calculation only, it is an artifact of the forumula. See point 1 above. The onboard computer does the assigning itself based on the letter code N, S, E and W. The subroutines I created to check for polar and due North or south were for the standard oblate spheroid sine and cosine formula. If you check HP literature they provide some examples for the 25C and 29C(?) using the standard spheroid formula and advise that traversing the pole will provide and error.

Cheers

[Geoff Quickfall]

Hi Max and others!

To further extend Max’s explanation:

1). On the 41CX and 71B I established a routine to check for alpha N, S, E and W. This would then assign a -ve or +ve value for the calculation in the routine. Yes, co-ordinates on the aircraft are entered as a +ve number with the alpha value attached to the front:

On Boeings and the DC10 INS N45 15.6 with seconds as a decimal.

2). There are defined (named) waypoints, those that are part of a programmed data base and undefined waypoints. Overseas operations differ from land based operations in that the waypoints that are not defined (undefined or unnamed) waypoints. These waypoints are not found in the data base and are entered by latitude and longitude. These occur on the North Pacific, North Atlantic, Uncontrolled Northern Domestic airspace and anywhere land based airways do not exist. They are based on the least time track (shortest fuel and time track).

Procedures for checking the undefined waypoints after the computer (FMC) is loaded require a total distance check (last page of the FMC), ETA for total route (winds are also inserted) and a distance and track check between each waypoint and compared to the printed flight plan created by a mainframe (for Air Canada we used Lufthansa flight planning).

Further, a reroute on the North Atlantic was not uncommon when entering Scottish Airspace north of the published tracks (Vancouver London/Frankfurt/Paris/Rome/ Europe) as our timing for entry was at the same time as the new published tracks for the next 24 hours were published and in use.

This is where the Distance.Track routine was used as it supplied the distance.track check independently of the FMC and since the reroute was not on a flight plan, there was no independent printed flight plan to compare too.

As stated, the distancd.track check MUST be done at the gate or in flight to confirm that the waypoint latitude and longitude were input correctly.

The attached photo is of the canadian northern domestic airspace undifined waypoints to entry into scottish airspace. Note the lat and lon waypoint entries which are entered by hand, or if your company can afford it, loaded by ACARS automatically during pre-flight duties.

Cheers,





You can see the latitude and longitude are followed by initial magnetic track, initial true track and distance. These can be confirmed by the distance.track routine.

[Guenter Schink]

(08-21-2024 11:17 PM)Geoff Quickfall Wrote:  Hi Max,

When I started with the airline in 88 there was nothing but nomographs. A small 2K on board computer called a PMC (performance management computer) and of course the INS with a whopping RAM for 9 waypoints.

...

When I started as a copilot on the Boeing 707 with the German Air force (Luftwaffe) in April 1974 navigation was the job of a navigator still, using loran, astro navigation and other ancient stuff. Our routine flights were calculated by Lufthansa computers. Quite often, when en route with President, Chancellor or Ministers, we had to do ad hoc trip calculation as they simply changed destination. Ever seen a thick book with tables of integrated range? That was very time consuming and error prone.
What a joy, when half a year later in Oktober 1974 our 707s where upgraded with INS.

The navigation branch bought an HP97, but obviously nobody did it use effectively. So I put my hands on it and over some time did an in depth data analysis of the integrated range tables. Using a regression analysis I came to a very reliable formula to calculate the required fuel for a long haul trip.

This was of course not a certified procedure, but using the integrated range tables after you know the result already made life much easier. And this motivated me to buy an HP41c, which was quite expensive for a young captain (rank not role), to have my own private flight performance computer.

50 years ago -- hmm, sigh!

Günter

[Geoff Quickfall]

Hello Gunter,

Sitting with the HP and regressing the nomographs!

Talk about regressive fun!

Cheers!

See you in September!

[Guenter Schink]

(08-25-2024 11:08 PM)Geoff Quickfall Wrote:  Hello Gunter,

Sitting with the HP and regressing the nomographs!

Talk about regressive fun!

Cheers!

See you in September!

Were integrated range tables still in use in recent years?

September, yeah - Günter

[Maximilian Hohmann]

Hello!

(08-26-2024 03:33 PM)Guenter Schink Wrote:  Were integrated range tables still in use in recent years?

I doubt that they are still used in paper form in real life. But the subject is still taught and there are questions in the ATPL theory exam so at least for training they still exist.

Regards
Max