Hi,Like alot of you guys i use TOPCAT for calculating my Takeoff speeds and engine settings and as a result given a relativ safety runway margin as well.I have 2 questions. 1. I cant find any Tabel in FCOM that provides with the same information so i must have missed something and btw what do real pilots use to calculate this ? They must have some easy tabels printed out. (like i have with the Maddog for FLEX)2. In TOPCAT we have a safety margin . Is this also stated in official boeing calculations methods?Off topic but related to TOPCATFor landing calculating VREF we have LDR (Landing distance required) and "actual" . Why do we need 2 different facts ?ThanksMichael

1. I cant find any Tabel in FCOM that provides with the same information so i must have missed something and btw what do real pilots use to calculate this ? They must have some easy tabels printed out. (like i have with the Maddog for FLEX)

I've basically used 2 methods: Automated through ACARS. Easy. Just make sure you put in any contamination.The book method: Broken down by airport, runway, flap setting. Find out if you can take off in the current conditions. Then look to see what temperature can handle your actual weight. That's your assumed. Off course there are several fudge factors built in.

For landing calculating VREF we have LDR (Landing distance required) and "actual" . Why do we need 2 different facts ?

One is a "factored" number that some would argue is for dispatch while on the ground. The other is the "unfactored" number. There's a big discussion about this on a few other sites. Take your pick on that one.

1. I cant find any Tabel in FCOM that provides with the same information so i must have missed something and btw what do real pilots use to calculate this ? They must have some easy tabels printed out. (like i have with the Maddog for FLEX)

Matt partially answered, I will add to that, that you can find some tables in FCOMv1, but most of what is used to support a program such as TOPCAT, ACCULOAD etc. can be found in FPPM rather. FPPM is not supplied by PMDG and as I gather, is not considered a pilot manual, just as AMM is not.

2. In TOPCAT we have a safety margin . Is this also stated in official boeing calculations methods?

well I guess it is computed always, and if it is shown depends on program configuration. What I have seen used around, does not show that.

Thank you for the answers. I will look into the other thread regarding the LDR .In the FMC on Takeoff Page 1 you have the runway for takeoff and __00 feet remaining. I never enter anything here but should i and what is it worth?/Michael

Hi Michael. To answer your question:FCOM Vol 2 page 969[Option – Runway remaining update with TO/GA activation, FMC U10.2 and later]Automatically displays the departure runway from the RTE page.If a runway remaining distance is not entered and GPS UPDATE is OFF, the FMC updates to the runway threshold when TO/GA is pushed.If a runway remaining distance is entered and GPS UPDATE is OFF, the FMC updates to the runway length remaining when the TO/GA switch is pushed. TO/GA position update inhibited if GPS UPDATE is ON.Following TO/GA update, the runway identifier and any entered shift value are highlighted in reverse video characters.To remove a RWY REMAIN entry, reselect RWY on RTE page.As to your previous questions:1. Electronic Flight Bags are used. They have software (much like TOPCAT) installed which calculate parameters with respect to aircraft performance.Go to www.casa.gov.au/airworth/awb/00/017.pdf for a basic overview, then search the aviation regulator for your country for similar rules. We currently use Panasonic toughbooks on our fleet which have our manuals etc as well as software similar to TOPCAT for performance calculations.2. I don't know, and can't be bothered answering.All the best.Ashley Frew.