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-   -   feeder fix time/ required time of arrival (RTA) (https://www.pprune.org/pacific-general-aviation-questions/433328-feeder-fix-time-required-time-arrival-rta.html)

Capn Bloggs 25th Nov 2010 04:21

Gday Amber,


We usually have the Dash crews calling visual at 30 miles and half the jets not calling visual until on base.
Local knowledge and also different performance probably plays are part in that.


This is a hassle as I am actually sitting in ML centre and only getting updates on the weather from my capable colleagues in CB tower.
I'm sweating on you getting visual as #1
Not a regular visitor to CBR, but I see that the only true visual approach is for non-jets, the Bungo via Endor. Unless you cut jets in short if they call Visual, would they not be following the STARs, which all go to/via an instrument approach?


Theoretically it is a pilot responsibility to stay above the steps on a visual approach.
Precisely why I defer calling Visual until later, especially if I am at an unfamiliar airfield. I can't set the CTA steps into the FMS and I don't believe that I should have a TAC chart out trying to make my jet conform with too-steep CTA steps in this day and age. If that annoys the system, then so be it. There should be a wholesale revamp/reform of the CTA steps around Australia as jets no longer drop out of the sky. It bewilders me that, at my home base, the amount of extra workload on pilots and controllers alike because of inappropriate steps is tolerated by AsA.


One of our major customers told us in writing a couple of years ago that if they were early on their schedule they would fly econ, if they were on time they would fly profile and if they were late they would fly fast.
WTF???
We don't know where you are reference your company schedule so have no idea what speeds you are doing unless we ask.
Communication problem for the AsA headshed methinks. Our company has a standard speed and given that aircraft have to fit into a system that has other users, it is reasonable that they also have a standard speed.


Untold times bus crews have advised that they can't make a FF time[think they will be later] only to have them sail through the ff early.
I'm not flaming here.
I just think there is a limitation with the FMS and we take it into account.
My aircraft is different but the FMS is the same type. From where I sit, it's a POP to hit a feeder fix time on the dot provided we're given enough warning.


With 5-20 different aircraft types in the mix flying different profiles even in the same company it is usually 'organised mayhem'
Selfish operators with no regard for the other people/operators in the system.
Metron will sort them out. ;)

Enjoy the cricket.

Nautilus Blue 25th Nov 2010 05:14


inappropriate steps is tolerated by AsA.
Accepted wisdom at work seems to be that its political, RAPAC and all that.


From where I sit, it's a POP to hit a feeder fix time on the dot provided we're given enough warning.
Just curious, but does the amount of warning affect the accuracy as well as how much time you can gain/lose? For example, if instructed to lose say one minute while already on descent (I know we shouldn't) is that harder to get spot on than say 2 minutes but while still in the cruise?

Capn Bloggs 25th Nov 2010 05:37

NB,

does the amount of warning affect the accuracy as well as how much time you can gain/lose? For example, if instructed to lose say one minute while already on descent (I know we shouldn't) is that harder to get spot on than say 2 minutes but while still in the cruise?
We either can or we can't. It's all a case of what the FMS says: if it says the FF time, then the aircraft should get there on the time provided the crew fly at the speed the FMS wants.

So the short answer is: no. If we get told to speed up/get our FF time brought forward, it's simply a case of seeing if we can achieve it. We can or we can't, no "accuracy", per se, involved.

Something else to consider (may have been brought up earlier in the thread): our FMS only indicates to whole minutes (at least until the last waypoint before the FF). So theoretically, an aircraft with a FF time of 12 could get there at the back end of 12, and a follower could get there at the front end of 14. That's quite a difference in separation compared to the other way round. Some of us adjust the descent speed to arrive just after the minute changeover.

Jack Ranga 25th Nov 2010 08:01


It's all a case of what the FMS says: if it says the FF time, then the aircraft should get there on the time provided the crew fly at the speed the FMS wants.
If it's a Boeing it will, if it's a Bus it wont. Busses are like ASA managers, they promise they will then inform you at the last moment that it's not possible, not in writing so not enforceable :ok:

Capn Bloggs 25th Nov 2010 21:54


If you are not ALL playing to the same songsheet (shared dynamic winds aloft) it is a zero net sum game. Same with descent speeds/profiles.
Flight planning systems, even NAIPS, give winds that are accurate enough and certainly do the job. Sure, speed management is required by the crew; you can't just set the speed to make the FFT at 200nm and then do nothing else.

John Citizen 22nd Mar 2011 14:06

Two pilots have recently just told me that we can be arrive/leave at a feeder fix up to 30 seconds early :eek:

Now where does it say this anywhere please, anyone ?

ATC care to comment please.

Blockla 22nd Mar 2011 18:48

The time separation at feeder fixes is initially strategic... the gap to achieve the landing rate becomes the tactical element (although most of the time they are the same)... If a pilot turns up 30 seconds early then so be it, hope the one ahead isn't 30 seconds late... This is when tactical control will be applied, vectors, speed or both, probably resulting in the crew blaming ATC for not knowing what they are doing...:8 In the ATC world 30 seconds is effectively the exact time. ie 20 and 30 seconds is the same minute as 21 and 29 seconds... both are on time for time 21...

haughtney1 22nd Mar 2011 19:09

NZAA-YMML B777

Just after TOD "cross xxx at time xxx"....
"negative unable due a/c performance"...."big shiney plane 123, please state a/c performance issue"
"ahhh we would stop flying due to stalling":}

Just wondering if these RTA's consider real world performance?

makespeed250kt 22nd Mar 2011 20:23

haughtney1, **** happens. It's a dynamic enviroment. Get over it and get on with it!

And yes, controllers would be aware that some FF times issued might be a stretch for the crew.

If ya can't do, expect vectors!

FFS

Mr. Hat 22nd Mar 2011 20:35

I've flown with some guys that have a relaxed attitude towards it (30-45 seconds) and you could set your watch on getting vectors.

Jack Ranga 23rd Mar 2011 03:27

If you bull**** about being able to meet the time and you're early, you WILL get vectored. (unless things are running better ahead of you)

If you are late you will either be re-calculated which could result in a self induced shafting or if they slow everything behind you everyone else gets a compound shafting.

If they give you a time that's un-realistic it may be to save extra R/T time (The controller knows you can't lose that much time and wants to know how many minutes to lose in a vector) or it may be just a tool that couldn't get into uni, has had nothing to do with aviation and doesn't understand what they are asking you to do (not many of these).

I think AIP says you can be a minute early, but that's hardly in the spirit of things is it? As a controller it's relatively easy to lose a bit of time, but gaining it when things have stuffed up is difficult at best and costly for airlines.

Would love you fellas to sit in with the flow or Approach or Arrivals (or whatever they call it these days) WHEN IT'S BUSY, not when PR (:ugh:) deems it acceptable for you to visit.

haughtney1 23rd Mar 2011 07:08


haughtney1, **** happens. It's a dynamic enviroment. Get over it and get on with it!

Nice.....

Jack I've been lucky enough to visit West Drayton (UK) on several occasions before it closed, I even had a crack on the approach control/director sim and can appreciate the tough job that it is.
I just wonder is its considered realistic to expect a 777 to reduce to a G/S of 200Kts from FL340 by the people who plan these things..thats all:ok:

max1 23rd Mar 2011 08:02

Don't sweat it Haughtney, someone giving you that won't be around long, they will soon be promoted.

Jack Ranga 23rd Mar 2011 10:33


someone giving you that won't be around long, they will soon be promoted
lol :D :D :ok:

Point taken Haughtney, personally I don't give you that crap when you call at Gemac.

If you hear:

'ANZ. . . Adjust speed to cross BADGR @ time _ _ @ 250kts, if you'd like to set up for a 250kt descent all the way and advise how many minutes need to be lost in a vector' that'll be me. (crap....no promotion for me :ugh:)

haughtney1 23rd Mar 2011 13:00


If you hear:

'ANZ. . . Adjust speed to cross BADGR @ time _ _ @ 250kts, if you'd like to set up for a 250kt descent all the way and advise how many minutes need to be lost in a vector' that'll be me. (crap....no promotion for me )
Haha if I hear that I'll be thinking "holy f*$k, I've made it to the hallowed halls of the Koru tailed bretheren....and its only another 23yrs to a command course:E"


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