syhar. BOAC DOES know what he's talking about.

N1 Limit has, I think, highlighted a widespread issue of the lack of performance understanding by many pilots in many companies. I haven't been in this game too long myself (~8 years) but sometimes I find the ideas and concepts, or lack thereof, that some of those who sit next to me have regarding performance simply breathtaking!

A basic understanding of Perf A, the performance manual or section of your aircraft's AOM/FCOM and the preamble to your company's RTOW charts (or EFB, haven't used one yet) is surely all that is required. Any more knowledge than that is a bonus, but would make sense to have IMHO.

Is it an industry wide problem? I've definately seen differences in standards of Perf training between airlines, and it's been a constant decline. Perhaps, as a lot of practical Perf teaching comes during line training, that is taken as gospel, and further reading is not undertaken? Though I have experienced more than one trainer preaching utter tripe regarding Perf.

Even with the more complex weather and airfield combination, a reasonably accurate RTOW calculation should not take more than a minute or two, and if using an EFB, does the manual not explain how to derive your RTOW?

I'm definately becoming a fully paid up member of the grumpy git club. Don't get me going on wet runways...

In the good old days, before they enclosed the cockpits and removed the top wing, we did our own loadsheets manually. Not too difficult, or even time-consuming, but it did give an understanding of the performance calculations. In fact, in the military, we didn't even have WAT limits for the runways, but calculated them from the graphs and charts. (OK, that WAS time-consuming)

"BOAC DOES know what he's talking about."

How can he, since he has never used EFB? He is from another era. The OP posted a valid and sincere question, and BOAC immediately begins to mock him, which seems to be his style.

Anyone for post #20?

I made an assumption based on the Boeing OPT that we use, and I presume most Boeing operators would use.

Thanks, Scio, but it is not clear from that 'short' PDF whether a TOW is required before an RTOW can be determined, which is not logical. Denti's 'default' structural + 'xx' and max thrust rating seems to be one solution - or simply a manual high TOW entry.. The system described by N1 and tfs would appear to be suitable for a 'comfortable' scheduled op, with CLC etc, but not suited to N1 who for some reason "wanna calculate my useful load" although I feel if he/she did actually understand what RTOW is the answer to post #1 would have been obvious

Are there any other links to usage of the OPT? I would appreciate an insight as my last airline muttered and mumbled about using it but never did before it went bust.:)

Like a few others, I still vote for care-worn perf sheets and a space at the bottom of the PLOG. At least you know what you are doing.

BOAC......PLOG

Now you are talking my language.....perhaps even standard fuel loads as well.
I remember we had 6 tons or 7 tons or ultimately full tanks on the 1-11.
That made life easy.

And we had ball park figures drummed into our brains for RTOW and V2 etc as a gross error check.

Back to the original question...

RTOW is the lowest of TOW encompassing limits such as MLW, MTOW and MZFW.
The limit in an EFB application can be found by calculating the takeoff/landing performance without entering the landing weight, which gives you MLW using existing conditions (those you selected such as airport/runway/temperature/qhn/...).
In essence the EFB allows you to calculate DISPATCH Landing Weight and MRTOW.
What EFB are you using?

BOAC,As I mentioned earlier, this is the software we use. To determine the RTOW, all parameters (a/c, runway, intersection, wx, bleeds, thrust, flap, CG, etc) except TOW must be entered. It will then calculate the maximum TOW possible for the conditions. If an actual TOW is also provided, then it will calculate the actual performance (N1, speeds, etc) with options for assumed or TOGA. Obviously, if the actual TOW exceeds the max or RTOW it will burp at you.

Thanks to the last two who 'describe it as I would expect it' - it would appear that N1 and tfs have some sort of 'inferior' EFB.

Thanx svhar for being supportive,@ skyjob we use LIDO system EFB but for it to give you PLTOW it needs a Gross weight with Wind,OAT,QNH,hence i needed to know how to work that out.

I am not familiar with the LIDO system, so I will not comment. But this is what the forum is about. Most of us will try and help, if we can. Don't let the Oozlum bird farmer scare you.

Thanks very much svhr for being supportive that's the attitude i looked forward to getting.Best regards