'Uncontrolled Rest' again? Virgin 206

[jetsam]

VIRGIN 206 lost or never made contact with Ulaanbatur control Mongolia for at least 30 minutes from around 0315 UTC on 5th March flying eastwards on B330 between Nigor and Silus. Perhaps, for some time previously on the Russian sector. Multiple attempts by ULaanbatur ATC and another aircraft ahead on the route, which was requested to contact them on control frequencies, the Emergency guard and the air to air frequencies failed. There was genuine concern that if they entered Chinese airspace without regaining contact that there would be an unfortunate response from the PLA AF. Luckily, probably due to the intervention of their cabin crew, they responded about 40 minutes prior to the handover. Another more wide awake voice later took over the R/T duties.

Is this another case of reduced manning on late night Long Haul flights resulting in insufficient in flight rest on back of the clock sectors? Are Virgin operating Four or only Three man crew to the Far East?

Had this continued or happened thirty minutes later, it could have been much more interesting - in the Chinese way..........

[Flying Clog]

Yup, welcome to my world :{

[safelife]

(ATC) looks up SELCAL code of concerned flight (field 18 of ATC flight plan)
(ATC) passes SELCAL code to a suitable relaying aircraft
(Relaying aircraft) SELCAL-pages lost comm aircraft on last known frequency and 121.5

Problem solved, isn't it?

[Bernoulli]

That's a cracking example of problem solving you've got yourself there Safelife :rolleyes:

[golfyankeesierra]

Won't work; aircraft can only receive, not send selcal.
How about a telephone call from ATC to the company and they just call them via Satcom?

[philbky]

Surely a simple solution to alert the aircraft would be to install a light and a bell in the Cabin Services Director's station which could be called in the same way as SELCAL should the cockpit fail to respond to repeated voice calls on VHF/HF and to SELCAL. Acknowledgement of the call from the cabin by a cancelling system would need to be followed by contact from the cockpit to confirm all is well.

[HeartyMeatballs]

If it was uncontrolled why don't the cabin crew call periodically? It's every 20 mins in my airline. If it was controlled rest then the pilot not sleeping should ring the cabin periodically. If that wasn't done then why?

[wiggy]

If it was uncontrolled why don't the cabin crew call periodically? It's every 20 mins in my airline. If it was controlled rest then the pilot not sleeping should ring the cabin periodically. If that wasn't done then why?

True, though I guess on occasions the cabin crew can get a bit busy and forget to check their watches..:oh: Anyhow some types have a "pilot intervention" alert or similar if no button pressing/switch selection is done for a set period of time..

Might have been "fatigue", could just a likely been volumes on the ACP turned down for some reason....

[safelife]

Who says an aircraft can't SELCAL another. Many ways exist, SELCAL tone coders for Windows, iOS, android are available.
In fact I have retrieved at least two "lost souls" over the Atlantic (one with Iceland, one with Gander, both were happy to provide the code) exactly like that.

[Load Toad]

..time for vibrate function in the seats..

[Pontius]

Who says an aircraft can't SELCAL another. Many ways exist, SELCAL tone coders for Windows, iOS, android are available.

Well, I say none of the four commercial types (Boeing) I've flown can SELCAL another. You may have an app installed on your phone and you may have access to the internet in flight; well done you. Normal pilots do not have a SELCAL app on their phone and not so many have internet access, so your solution is crucially flawed.

[wanabee777]

Must not have been a triple 7.

[ion_berkley]

Well, I say none of the four commercial types (Boeing) I've flown can SELCAL another. You may have an app installed on your phone and you may have access to the internet in flight; well done you. Normal pilots do not have a SELCAL app on their phone and not so many have internet access, so your solution is crucially flawed.

Sigh. Thank goodness for microphones. https://en.wikipedia.org/wiki/Phreaking

[MarcK]

SELCAL App for Android (https://play.google.com/store/apps/details?id=de.fbits.selcal&hl=en). This SELCAL app is a tone encoder which sounds SELCAL selective calling tones. The tones are produced in accordance with ICAO Annex 10 Volume II, ARINC Characteristic 714-6 Mark 3, ARINC 714A Mark 4 and ASRI SELCAL specifications.

[safelife]

Thanks, ion, thanks,Marc. No internet connection required either (why should it... you just have to sound those magic tones ;) )

[sandos]

Thanks, ion, thanks,Marc. No internet connection required either (why should it... you just have to sound those magic tones ;) )

Technically, if you didn't install the app before-hand, you would require an internet connection.

[Chesty Morgan]

And technically it's not an aircraft SELCALing another aircraft either. ;)

[FullWings]

Before we castigate the crew, could this be another case of sleeping receivers ("http://www.skybrary.aero/index.php/Sleeping_Receiver”)? We’ve had quite a few incidences of this in our airline...

[ve3id]

Who says an aircraft can't SELCAL another. Many ways exist, SELCAL tone coders for Windows, iOS, android are available.
In fact I have retrieved at least two "lost souls" over the Atlantic (one with Iceland, one with Gander, both were happy to provide the code) exactly like that.

While it may have worked for you, the combination of the frequency response of the iPhone's speaker and that of the aircraft microphone would mean that it could not be relied upon for any more than marginal reliability. Therefore not designed-in to procedures. Real encoders are wired directly into the modulator.

I wouldn't mind betting that aircraft modulation circuits have frequency response shaping to roll off the high frequencies of white noise found on the flight deck, thus causing more of a 'twist' between the two tones. Did you guys really believe that macho voice was all yours without artificial help?

[Xiamen]

How may pilots on this flight?
We should put enough crew on longhaul flights to enable them to get proper inflight rest. Then maybe we would not have this discussion.
It's not about finding ways to wake up pilots, it's about stopping pilots from falling asleep in the first place.

[IcePack]

Xiam the bean counters rule on that. Safety is just a word to them unfortunately.
I spent years doing 2 pilot long haul with an occasional extra pilot to get around the old sector rules. Trying to keep awake was always a challenge. But despite requests even for a fire watch on empty long sectors fell on deaf ears of said bean counters.

[frangatang]

FFS! All l do when on controlled rest is call the cabin crew every half hour. If they dont hear from us within another 5 mins, they call us. Simples.

[Doors to Automatic]

Is the aircraft not fitted with some sort of alarm that sounds after a pre-set time if no control inputs (including key presses) are detected? With this flight operated by a 787-9 I am even more surprised if that is not the case.

[sky9]

Before we castigate the crew, could this be another case of sleeping receivers ("http://www.skybrary.aero/index.php/Sleeping_Receiver”)? We’ve had quite a few incidences of this in our airline...
I seem to remember that when an aircraft transmits it's receiver is "earthed". If the relay sticks reception is not possible until the aircraft transmits again and the relay probably opens.
I'm sure a radio engineer can give a more accurate description of the function.

[Plumb Bob]

In my current case of uncontrolled awakening (all dark and quiet outside), let me give you a correct link to the ‘sleeping receivers’ web page that has been mentioned in this thread two times already in a sort of misspelled format that awakens an error page only.
The correct link is: Sleeping Receiver - SKYbrary Aviation Safety (http://www.skybrary.aero/index.php/Sleeping_Receiver) .

[wiggy]

Is the aircraft not fitted with some sort of alarm that sounds after a pre-set time if no control inputs (including key presses) are detected? With this flight operated by a 787-9 I am even more surprised if that is not the case.

Doors -I asked / mentioned that (permalink #8) but got no response ;).

Given that our 777's were delivered with that alerting function and even our 744's were retrofitted no doubt as part of some software upgrade I'd be mighty surprised if it didn't come as standard out of the box on the 787.

Can't remember exactly how long you have to wait until the EICAS alert is triggered but it is under 30 minutes, and for those that don't know, if the visual alert is ignored it can start to get very noisy very quickly.....:uhoh:

[Wirbelsturm]

Is the aircraft not fitted with some sort of alarm that sounds after a pre-set time if no control inputs (including key presses) are detected? With this flight operated by a 787-9 I am even more surprised if that is not the case.

You mean the 'Pilot Response' EICAS message that sets off the Master Warning chime if no transmit or MCP button is pressed, pulled, twisted or rotated?

The company sets the time limit and it's active when the aircraft is Clean, above 20,000ft and in the cruise.

Never catch on!

crossed (again! ;) ) with Wiggy. :D

[MikeBanahan]

I seem to remember that when an aircraft transmits it's receiver is "earthed". If the relay sticks reception is not possible until the aircraft transmits again and the relay probably opens.
I'm sure a radio engineer can give a more accurate description of the function.

Whilst I'm not specifically an aircraft radio designer, I can speak for many other forms of transmit/receive combination and relays went out in the 70s there, being replaced by PIN diodes - which are entirely solid state and don't stick, nor is there a limit on the number of times they 'switch' (since they don't actually switch).

I've designed and built a number of transceivers, so this is an area where I have working knowledge, just not of the particular requirements for aviation certification. For all I know relays may still be common practice but that would be a source of considerable surprise.

I'd love to see any concrete evidence - particularly repeatable - of the 'sleeping radio' phenomenon. Whenever you get believable reports of that kind of behaviour, you start constructing imaginary scenarios of a combination of circumstances that could cause the equipment to behave in that way. I'm fairly good at fault-finding in that way but there are no obvious failure modes that I can think of to cause the reported behaviour. If imagination doesn't lead to a cause, next you need an actual example to investigate.

[Ozlander1]

A stuck mic would be the probable cause for a sleeping receiver.

[Airclues]

If it had been a problem with the radio then the pilots would not have heard anything from either ATC or other aircraft. Would not most people become rather concerned if they hadn't heard anything for thirty minutes in that part of the world?

[Akrapovic]

Source . . . ?

[glum]

A stuck mic should only take out 1 radio, and I believe there are at least four on board: 2 VHF and 2 HF.

[Wageslave]

As ever when we reach explanations in the n th degree of unlikeliness it is to the obvious one should look.

Most "sleeping receivers" are almost certainly are brought about by sleeping pilots.

Rationale? There being hundreds of alert pilots for every sleepy one we should be swamped with credible reports from alert pilots who have caught their receivers asleep yet we are not.
Oddly, "Sleepy receivers" only seem to get detected by ATC, and anecdotal evidence is often that the initial response from aircrew once the "receiver" has awoken is far from alert.

Go figure what the "sleepy receiver" really is...

[IcePack]

Having had an incident of this type a long time ago. It transpired that the previous sector had failed to hand us over and due to ducting the frequency picked up another station on the same frequency, so as far as we were concerned we could still hear the controller. (Note the change over boundaries were not as clear as they are now)
Of interest I was discussing this in a bar, when an old boy commented that once in a viking(i think) he heard Heathrow tower whilst on finals into Delhi.