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-   -   Prank SELCAL call? (https://www.pprune.org/tech-log/400065-prank-selcal-call.html)

hector 27th December 2009 17:29


One is usually too busy setting up a departure under time pressure to have time to even consider what HF frequency is on
Rainboe, check Part A, 8.3.2.6.1

"Preflight checks on all flights, HF radios are to be tuned....etc.":E

However, I do agree with you. There is seldom time.

Spooky 2 27th December 2009 17:34

Rainboe, for starters I have never had a SELCAL go off during a takeoff so my personal experience is certainly less than yours. My comments were directed at something less than 30kts and nothing more. Approaching 80kts might be a different story depending on circumstances surrounding the departure and it's certainly not a briefing item on any of my departures. Once TOGA has engaged it would certainly affect how this would be handled.

Cheers:ok:

18-Wheeler 27th December 2009 22:12


One is usually too busy setting up a departure under time pressure to have time to even consider what HF frequency is on- selcal is automatically covering HF
Of course there's time - part of the panel setup and only takes a couple of seconds.

MainDude 28th December 2009 07:05

I agree with Rainboe, stopping for an HF call is not usually a factor to consider.

Our circumstances were different though,
- we were the only aircraft there (no others in approach either),
- long runway, engines had not fully spooled up yet,
- as an operator we don't normally get HF calls, and when... in the past they have been for serious reasons.
- below 70kts the TO Inhibit warning/(call suppression) feature isn't yet active so by design we're open to receive new information & have to time to act on it either way.

Thanks for all the responses so far. The main question I had was whether other guys were also experiencing this kind of thing, and whether the trend is increasing...

Best wishes for the festive season

MainDude 28th December 2009 07:12


Quote:
One is usually too busy setting up a departure under time pressure to have time to even consider what HF frequency is on- selcal is automatically covering HF

Of course there's time - part of the panel setup and only takes a couple of seconds.
On our aircraft it's fully automatic & there's nothing to set.

Rainboe 28th December 2009 07:43

We must remember a lot of people use these forums to learn experience and develop their skills. It's important to stress the lessons about making valid reject decisions. I have had selcal go off on takeoff roll- it was just an eyebrow raising event with no thought to reject. Via HF, you are not going to receive any information in those seconds that is of any importance, and students must understand that a reject is a fairly serious event, even at low speed, and such a decision must be taken sensibly. A reject creates a hazard and stoppage on the runway requiring extensive ATC intervention, and some airports require an automatic runway inspection as they don't understand what has caused it.

Selcal alerts are not unusual, even when apparently nobody is calling you. Maybe it is a slip of a radio operators hand, or just spurious warnings. Perhaps we should have it disabled automatically when the wheels are down and not compressed.

punchus 28th December 2009 14:21

Certain 320/321 with a specific model of AMU in the Comms set up will generate spurious selcals if box 2 has an atis frequency set in the standby window. Don't ask me how it's avionics black magic stuff. Just deselect the atis freq on box 2 and it's fine.

hector 28th December 2009 18:48


Of course there's time - part of the panel setup and only takes a couple of seconds.
Yes, to dial up a frequency only takes a couple of seconds but if you do it "by the book" you would then call Stockholm Radio for example to check transmission/reception, get a Selcal check and if there are more than one box, it takes a little longer.

18-Wheeler 29th December 2009 03:53


Yes, to dial up a frequency only takes a couple of seconds but if you do it "by the book" you would then call Stockholm Radio for example to check transmission/reception, get a Selcal check and if there are more than one box, it takes a little longer.
That's not what I meant - I meant that it's not difficult to make sure you either have the SELCAL not selected to HF, the HF's off, or the HF's on a non-used frequency. Takes scant seconds.

MainDude 29th December 2009 05:22


Certain 320/321 with a specific model of AMU in the Comms set up will generate spurious selcals if box 2 has an atis frequency set in the standby window. Don't ask me how it's avionics black magic stuff. Just deselect the atis freq on box 2 and it's fine.
This was our case. Is this "deviation from original design objectives" documented anywhere, or is it something you've noticed?

slamer. 29th December 2009 08:19

Im with Rainboe on this one. An RTO for a selcal is crazy.

punchus 29th December 2009 09:54

Main Dude: to answer your question you would need to get your engineering department to confirm with airbus if the amu's used in your comms set up are prone to spurious selcals. I believe the problem may have already been modded out. I have had the same on numerous occasions regularly over the bay of biscay.
Hope this helps.

Surrey Towers 29th December 2009 11:52

BOAC wins! :ugh:

ACSfirstfail 30th December 2009 17:11

On the L1011, as part of the scan checks, we select the selcal's to vhf 1 or 2. Teaching is you are less likely to get a spurious selcal on vhf. Better still, certain of our frames have a VHF 3 selcal position and we don't have a third vhf radio so we select that for take-off or landing.

Rainboe 30th December 2009 18:49

I'm not sure I know what to make of this advice:

Rainboe, check Part A, 8.3.2.6.1

"Preflight checks on all flights, HF radios are to be tuned....etc.
Most planes I have ever flown have selcal armed and ready to go and no ability to switch off. It doesn't matter what you tune your HF to, you can still have a spurious warning. If tuning ensured that you would not have a spurious alert, I could understand the advice!

Jumbo Driver 30th December 2009 20:33

Way back in the 70s (was it the VC10?), I seem to recall part of the Before T/O Check actually being to select SELCAL away from HF (e.g. to VHF) precisely to minimise the chances of such a distracting and usually spurious call during the departure.

Oh, and yes, I have had a SELCAL chime during the take-off roll ... and NO I would never reject a take-off for a SELCAL chime ...


JD
:)

FLCH 30th December 2009 20:42


Believe it or not; There are more than one airplane flying with the same selcal code!!!
In the same fleet no less !

I have answered for a sister ship several times with the same SELCAL code :*

mnttech 30th December 2009 21:00


Only two tones but 4 letters!
That's incorrect, each letter is a different tone, so you hear two tones together, then the other two tones together, making it sound like just 2 tones.

hector 31st December 2009 16:49

Rainboe,


I'm not sure I know what to make of this advice:
I never give advice. :rolleyes:

Following your earlier reference to time pressure and selection of HF radios, I was merely drawing your attention, with tongue in cheek, to the relevant section in Part A. The procedure, as laid down, (and which I don't think I have ever observed anyone doing!) requires some minutes to complete.

I do not necessarily agree with it.

tvrao 1st January 2010 01:55

Interesting discussion on SELCAL. I am surprised the system provided alert on HF system when a VHF frequency was selected.Normally the ATIS is on VHF frequency.
The SELCAL decoder inside AMU should have provided alert on VHF if spurious tones randomly coincided with selcode of that aircraft.
In case of Boeing aircrafts SELCAL decoder is a separate box, it is not part of AMU.
You can get indications similar to SELCAL(call light on ACP and chime) when you receive a message from ground station on ACARS . ACARS uses Center VHF (third VHF on Boeing aircraft) .


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