Step Climbs and Initial Decent Rates

[HeathrowAirport]

Hi Just a Question,

-N0455F360 TUC UM733 GIPNO/N0457F380 UM733 ABSUD/N0424F280 UM733GUBAR/N0371F180 T27 GURLU/N0362F160

As above for example... GIPNO is a step climb to FL380 is this commenced at 500+ FPM Maximum for passenger comfort.

And for decent with the seatbelt signs off whats the max decent rate in FPM?

I also note that when flying with Thomson they put the seatbelt signs on during decent, however with BA its more nearer the 10000ft mark. Is there any differences in there decents?

Thanks

[Rainboe]

The ATC flight plan is created hours before the flight when final payload and fuel are not known, so it is only a broad guide. The pilots on the day decide what altitude they want to fly at and when they want to climb, and negotiate with ATC. Nobody really takes any notice of the ATC flight plan for altitude- only route.

Climb is just commenced on VNAV unless it is a small climb of 2000' or so when you may do it on VS as the autothrottle will put on full power and then just control attitude to keep speed right. Initial climb can shoot up to high figures, but during the climb, the computer will control climb rate from zero to large figures- it is not steady. VNAV is overwhelmingly the most common speed control regime. VS produces a less high thrust climb if desired, but thrust does vary considerably to keep the same ROC.

For descent, the thrust comes back to idle, the speed is controlled, so rate of descent just has to look after itself. Again figures as high as 3500fpm are not unusual- this decreases as you get to 30,000'. Seat belt sign policy varies according to airline procedure- some put them on at 20,000', some 10,000', some 10 minutes, some 20 minutes to go. There is no limit of ROD without seat belt signs on- it is immaterial.