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'Uncontrolled Rest' again? Virgin 206

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'Uncontrolled Rest' again? Virgin 206

Old 8th Mar 2016, 20:40
  #21 (permalink)  
 
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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.
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Old 8th Mar 2016, 22:04
  #22 (permalink)  
 
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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.
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Old 8th Mar 2016, 22:16
  #23 (permalink)  
 
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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.
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Old 8th Mar 2016, 22:41
  #24 (permalink)  

Keeping Danny in Sandwiches
 
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Originally Posted by FullWings View Post
Before we castigate the crew, could this be another case of sleeping receivers? 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.
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Old 9th Mar 2016, 04:35
  #25 (permalink)  
 
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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 .
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Old 9th Mar 2016, 08:13
  #26 (permalink)  
 
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Originally Posted by Doors to Automatic View Post
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.....
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Old 9th Mar 2016, 08:14
  #27 (permalink)  
 
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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.
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Old 9th Mar 2016, 08:23
  #28 (permalink)  
 
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Originally Posted by sky9 View Post
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.
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Old 10th Mar 2016, 07:30
  #29 (permalink)  
 
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A stuck mic would be the probable cause for a sleeping receiver.
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Old 10th Mar 2016, 10:49
  #30 (permalink)  
 
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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?
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Old 10th Mar 2016, 12:40
  #31 (permalink)  
 
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Source . . . ?
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Old 10th Mar 2016, 13:05
  #32 (permalink)  
 
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A stuck mic should only take out 1 radio, and I believe there are at least four on board: 2 VHF and 2 HF.
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Old 10th Mar 2016, 16:17
  #33 (permalink)  
 
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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...

Last edited by Wageslave; 10th Mar 2016 at 16:27.
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Old 10th Mar 2016, 16:43
  #34 (permalink)  
 
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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.
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