Revived "passengers vomiting in VNAV mode" thread

[kevinh 409]

Sounds good to me.Kevin Hall

[RYR738 9]

I'm really looking forward to SP1b now.Sounds great Ryan !Thanks. Fred.

[Mean Aerodynamic Chord 269]

Can't wait!

[iainsmith 9]

You also must have a different add-on to me, mine does not do that.

Mine does and from the OP's ATC experience this would seem to be illegal.Iain Smith

[scandinavian13 5,192]

Guys,Whoever is trying to bring legality into this, there is absolutely NO legal requirement to maintain VSI at or above any value, in the FARs or the 7110.65 (which the OP should be extremely familiar with). The only allusion to vertical speed that is made is to say "if you can't better 500fpm, let ATC know." That's it. The pilot reports it, the controller takes a look at potential conflicts and makes a decision: if there's a potential conflict, the controller might just say "level off at [lower altitude];" if there's no conflict, its "roger." End of story. If you take issue with that, go back and read your FARs and 7110. ATC isn't on the lookout for pilots doing less than 500fpm (they can't tell fpm unless they do the math anyway - it doesn't show up in your datablock). The only way you'd be in trouble is if separation was lost, they pulled the tapes and looked at flight data and saw you were doing less than 500fpm and didn't report.Furthermore, if you're getting FPM limited at higher altitudes, you might want to check your OPT ALT. If you're too heavy for an altitude, you're not going to get there, or you're not going to better 500fpm on the way (especially up higher). Beyond that, you all also need to take a look at your CIs. High (unrealistic) CIs can cause the AP to be more aggressive in getting up and getting down, in regards to VS. If you're using reasonable CIs, expect reasonable rates. I take the time to learn how to operate my plane before I go fly it, and you can be sure that I'll also make sure it's not my fault the plane is doing weird things before making accusations. I suggest you all do the same."Well the REAL plane doesn't do this!!!" then I suggest you spend a little time learning how the real planes are operated before you get too upset. Real planes don't use high CIs. Real planes use derates. Real planes have passengers in them (and what a lot of people underestimate: real planes carry more cargo than you think, in the line of mail and company material - cargo draws more reliable money than passengers). Real planes have fuel in them (they carry a lot more than you think, and are probably carrying).Lastly, the thing that boggled me was the CPC in the OP's signature:As a controller, you should be aware of Appendix A. If you don't know it, there are ways to call it up at the scope, or you can bust out the paper. Appendix A lists the generic, expected climb and descent weights for the median weight of that aircraft type. Granted, these are really rough, but if the manufacturers are giving the FAA data that suggests an NG can get 4000 at median weight, you can be sure they'll get more at a lighter weight.Summary:If you're going to get upset that this plane isn't acting like a REAL plane, learn how to operate it like one, and then check your results.

[aentwis 61]

Thanks for the information in your post Scandinavian13. (sorry, can't see any real name in signatures on the mobile IPB version of the forum.)Makes the little time I have been getting in the NGX the last couple of weeks more fulfilling.Wish the day had more hours!Andrew

[kabekew 0]

As a controller, you should be aware of Appendix A. If you don't know it, there are ways to call it up at the scope, or you can bust out the paper. Appendix A lists the generic, expected climb and descent weights for the median weight of that aircraft type. Granted, these are really rough, but if the manufacturers are giving the FAA data that suggests an NG can get 4000 at median weight, you can be sure they'll get more at a lighter weight

No, we don't use appendix A at all in ATC in the U.S, Those are theoretical values, not real-world performance characteristics. I think they use those for the computer to X-out the altitude on the PVD if the Mode C exceeds it (to indicate a bad Mode C).

[scandinavian13 5,192]

No, we don't use appendix A at all in ATC in the U.S, Those are theoretical values, not real-world performance characteristics. I think they use those for the computer to X-out the altitude on the PVD if the Mode C exceeds it (to indicate a bad Mode C).

I understand they're theoretical. In fact, I know they are, and that shows in my earlier post (generic/expected/mean are all terms suggesting theory rather than hard fact). They aren't the values set in the Mode-C proofing. When have you ever gotten that on a passenger aircraft? The only thing I've seen trigger Xs on the mode C were fighters.That appendix is there, provided to the controllers to get a general understanding for how aircraft will perform in the most common scenario. In the end, most controllers just develop a "feel" for how early to descend certain aircraft, and which ones to give more room than others. So yes, you can get by without ever glancing at App A, but it doesn't necessarily make it invalid.