744 FMC flightplan vanishes amidst PROGRAM ERROR

[JSACKS 0]

Today I built a massive flightplan for flying KSFO-YSSY. I entered the DEP and ARR data and then went back to the RTE and started entering jetways and so on. For some reason that eludes me, I deleted the destination runway in the RTE pages and later in the day when I'd entered a lot more RTE data and tried to re-enter the arrival YSSY runway (ILS 16R), the FMC said "PROGRAM ERROR" and most of the RTE data and associated legs got automatically deleted.After a lot of dicking around with the FMC to try and find a way around this horrible PROGRAM ERROR message, I gave up, closed down FS9 and started again. Luckily I'd saved almost the entire flightplan in FSNavigator so it was a fairly quick re-build but it did give me the willies. I realized that I had no idea how to scrub a flightplan inside the 744's FMC and start re-building without closing the sim down.What did I do wrong and what should I do in the future to avoid this?Appreciate any guidance, thanks!Jonathan

[downscc 1,327]

I'm not sure what you did wrong or how the arrival runway got deleted. All I can offer is a tip: Enter the route without departure and arrival procedures and once it is satisfactory save it. Then while it is still loaded you can add the departure and arrival procedures. This way, if something goes wrong, you only need to reload the saved route and try to figure out why the route is giving you problems.When entering the route without departures and arrivals, start the route with the fix/navaid that is the final point of the departure and the final point of the route is the first fix/navaid of the arrival.Hope this helps.

[JSACKS 0]

Dan:Sound advice, thanks.I don't know myself what went wrong or why exactly but I since discovered that I can delete a flightplan totally by just deleting the departure point in the RTE page. I didn't know this until today!Jonathan

[Guest tompeel]

Dan:Sound advice, thanks.I don't know myself what went wrong or why exactly but I since discovered that I can delete a flightplan totally by just deleting the departure point in the RTE page. I didn't know this until today!Jonathan

That's great - I just found this after searching for a solution to my question how to program an emergency alternate. Could anyone at PMDG add this to their FAQs?