View Full Version : levelling off in descent
eastern wiseguy
16th Mar 2003, 22:58
Hi Guys
Over the past few days I have noticed a tendency for certain aircraft to level off for brief periods of time when they have been given a continuous descent clearance.It has caused me no problems but I am curious as to why it happens.The aircraft concerned are all B73...various marques and flown by the same company ....the area is around FL80....just curious..IN LIEU OF FAM FLIGHTS:rolleyes:
Could it be that the company wants its pilots try and smuggle as much as they can past the 10,000ft speed limit point until they think they can't get away with it anymore (i.e FL080) and they go for speedbrakes/level off to slow it down to a more reasonable speed?
Just an idea. I don't know how stringent the ATC are in enforcing that 250/10,000ft rule? Do you always notice when someone is "speeding"?
eastern wiseguy
16th Mar 2003, 23:46
hI obk thanks for the input ...as a rule I generally lift speed control as a matter of course..so I doubt that is it.I was wondering if there was a physical characteristic...I seem to remember that in the olden days the Tristar always seemed to level out at about 10000' and then started down again...of course it was all a long time ago and I may be mistaken :confused:
It could also be the pilots reducing speed from 250 to flap speed? Typically 210 I think for stage 1 flap on a 73. Then again, this rarely happens at FL80, more like 5000-3000ft when nearing approaching localiser intercept heading.
Otherwise, I'll pass on it. I thought it could be something to do with the cabin crew doing their final checks? so they level off for a while for a bit of "steadyness" and the pretty women goes into the flightdeck with the "Cabin Secure for Landing" thing.
cheers
obk
Its possible the guys are descending on profile using VNAV and theres a speed/height constraint plugged into the FMC telling the automatics that 250kts below 10000' is required; meaning the plane would lose the speed before descending beneath the 10000 restriction(you can place the speed/height restriction in yourself) ......but you say 8000 so possibly not :confused:
EADI
don't fly a 737 so only looking in from the outside hazarding a guess
:O
eastern wiseguy,
come to think of it, where you work does it happen on a particular STAR, and are there any SLP's? Height retrictions?
cheers
obk
eastern wiseguy
17th Mar 2003, 23:08
Hi OBK ...The "star " such that it is does not have any speed limits apart from 250 below 10 and the only height restriction is with traffic departing from a second airport in the TMA .I asked a guy today his rate of descent after noticing a serious decline and he said he was slowing down and the descent rate had dropped to around 500 fpm ....so that sort of answered the question!.Mind you if I am trying to get someone below holding traffic I would like to know if there was going to be any significant change in a descent rate ....A question for another time perhaps ...Thanks for the input .Bring back Fam Flights!!