Swiss A320 cabin pressure, "ATC refused descent request"
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Calypso :
Not in Aviation as a generic term . In Flight testing maybe, . In ATC assuming things nearly always lead to errors and incidents. We are trained never to assume. That is what HT was saying I think.
And a word of caution in your reasoning , ( not bad per se ) If you plan to use TCAS display to separate yourself to start and during an ED , you're in for big surprises. I would not do that. But a turn, even a slight one to get away from Navigation accurracy, absolutely !
West Coast :
Then we can assume you definitively not a woman 
Assumptions permeate everything we do in aviation
And a word of caution in your reasoning , ( not bad per se ) If you plan to use TCAS display to separate yourself to start and during an ED , you're in for big surprises. I would not do that. But a turn, even a slight one to get away from Navigation accurracy, absolutely !
West Coast :
Aviate comes first, not concurrently with communicate.
Assumptions do factor in. Especially as Calypso noted, in the area of performance. ATC watcher, as you're a pilot (my assumption being of a large turbine powered acft) is your performance for each takeoff predicated off the assumption an engine will fail? I know mine is.
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West Coast : I see what you are saying , we just have a different definition of the same word. The "asumptions" you mean are taking things into account. Yes as a Pilot I do those of course all the time.
In ATC "assuming" means that you " think" that it is or will be OK without checking.
Like say, issuing an instruction and not receiving an immediate read back : Assuming it is received and will be complied with is the kind of assumpions we are trained fromn childbirth to avoid.
Another typical assumption is expecting an aircraft to behave like 100 others did before in a similar situation . Therefore we do repeat the same instructions over and over again.
One of our training motto is :" in case of doubt, double check, never asume "
The 2 worlds are different.
In ATC "assuming" means that you " think" that it is or will be OK without checking.
Like say, issuing an instruction and not receiving an immediate read back : Assuming it is received and will be complied with is the kind of assumpions we are trained fromn childbirth to avoid.
Another typical assumption is expecting an aircraft to behave like 100 others did before in a similar situation . Therefore we do repeat the same instructions over and over again.
One of our training motto is :" in case of doubt, double check, never asume "
The 2 worlds are different.
Ok, agree with to terms. As to the second para, immediate responses are based on the assumption that the probability of hitting something below my level has a lessor probability than the danger of staying at altitude if that's even a possibility.
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is your performance for each takeoff predicated off the assumption an engine will fail? I know mine is.
I would suggest that you wouldn't assume an engine failure but that performance for take-off would be predicted in the eventuality of an engine failure. A little like the erroneous term used in American elevators, "In case of fire" instead of "in the event of fire".
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So far the discussion has centered around two players in the scenario. The pilot (aircraft) with the pressurization issue and the controller.
What about the other aircraft in the immediate vicinity that could be catastrophically affected by a pilot who descends first and advises ATC later? Is TCAS going to save you from a collision? Likely, but what if you're a heavy jet and your descent/ deviation has put another aircraft right into your wake?
Things to consider....
What about the other aircraft in the immediate vicinity that could be catastrophically affected by a pilot who descends first and advises ATC later? Is TCAS going to save you from a collision? Likely, but what if you're a heavy jet and your descent/ deviation has put another aircraft right into your wake?
Things to consider....
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To be fair, BA5390 was a bit more than a depressurisation issue - the windscreen blew out. This led to a specific problem regarding communication with ATC as the wind noise rushing through the flight deck prevented the F/O from being able to hear ATC's transmissions, and he had no way of telling whether ATC could hear him. Added to that, his emergency descent flightpath was going to take him through the feeder zones for London Approach.
Of course, all this is before you take into account that just to his left, the Captain had been sucked through the windscreen aperture, held in only by - intially - his toes caught in the ramshorn yoke, then by two cabin crew who held on to him for dear life throughout the rest of the sequence.
Hence my reference to it as an extreme example! That he managed to get a Mayday out after levelling out post ED shows professionalism and a presence of mind that many can but aspire to.
Of course, all this is before you take into account that just to his left, the Captain had been sucked through the windscreen aperture, held in only by - intially - his toes caught in the ramshorn yoke, then by two cabin crew who held on to him for dear life throughout the rest of the sequence.
Hence my reference to it as an extreme example! That he managed to get a Mayday out after levelling out post ED shows professionalism and a presence of mind that many can but aspire to.
Last edited by DozyWannabe; 19th Sep 2013 at 23:09.
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Interesting / worrying that the advice given to Denti by eurocontrol seems to contradict ICAO Docs procedures (cut and past below from UK AIC) which are also supposed to be ignored when flying in UK airspace.
God forbid we get any joined up thining on something so fundamentally serious
Then we have those that will blindly follow SOP regardless of rules or what is sensible.
Whatever happened to airmanship. Aviate (initiate the descent), Navigate (look out and don't hit anyone), communicate (7700 & get on that radio ASAP).
Turn or not as the case may be, that really depends on the factors of the day and your level of SA and knowledge of what / who is around you.
The last sentance below says it all!!
God forbid we get any joined up thining on something so fundamentally serious
Then we have those that will blindly follow SOP regardless of rules or what is sensible.
Whatever happened to airmanship. Aviate (initiate the descent), Navigate (look out and don't hit anyone), communicate (7700 & get on that radio ASAP).
Turn or not as the case may be, that really depends on the factors of the day and your level of SA and knowledge of what / who is around you.
The last sentance below says it all!!
2 ICAO Procedure
2.1 Procedures for pilots upon hearing an emergency descent broadcast are published in ICAO Doc. 4444 (PANS-ATM) paragraph
15.1.4. More recently, ICAO have published detailed procedures in Doc. 7030/EUR - Regional Supplementary Procedures paragraph 9.1
for pilots experiencing an emergency descent in the European Region. The Regional Supplementary Procedures are reproduced in
paragraph 2.2 below.
2.2 Doc. 7030/EUR states that, when an aircraft receiving an ATC service experiences sudden decompression or a malfunction requiring
an emergency descent, the aircraft shall, if able:
a. Initiate a turn away from the assigned route or track before commencing the emergency descent;
b. advise the appropriate air traffic control unit as soon as possible of the emergency descent;
c. set transponder to Code 7700 and select the Emergency Mode on the automatic dependent surveillance/controller-pilot data link
communications (ADS/CPDLC) system, if applicable;
d. turn on aircraft exterior lights;
e. watch for conflicting traffic both visually and by reference to ACAS (if equipped); and
f. co-ordinate its further intentions with the appropriate ATC unit.
2.3 The aircraft should not descend below 10000 ft amsl, or Minimum Safe Altitude, whichever is the higher.
2.4 Turning-off or Remaining on Track in UK Controlled Airspace
2.4.1 UK Controlled Airspace is complex and congested; traffic is often oriented on the airway in certain directions or flows. Therefore, if
able, pilots should remain on the assigned route or track whilst carrying out the emergency descent; unless to do so otherwise would
endanger the aircraft. Notification of this preferred action in UK Controlled Airspace shall be published in the UK AIP GEN section under
PANS-ATM paragraph 15.1.4 - Emergency Descent.
2.4.2 If a turn away from an assigned route or track is initiated, pilots should note that they may not be aware of traffic in their proximity
(especially if flying on an assigned heading): nor of aircraft below them, not on the selected frequency, in adjacent airspace sectors. However,
it is ultimately the pilot’s responsibility to take the action most appropriate in the circumstances.
2.1 Procedures for pilots upon hearing an emergency descent broadcast are published in ICAO Doc. 4444 (PANS-ATM) paragraph
15.1.4. More recently, ICAO have published detailed procedures in Doc. 7030/EUR - Regional Supplementary Procedures paragraph 9.1
for pilots experiencing an emergency descent in the European Region. The Regional Supplementary Procedures are reproduced in
paragraph 2.2 below.
2.2 Doc. 7030/EUR states that, when an aircraft receiving an ATC service experiences sudden decompression or a malfunction requiring
an emergency descent, the aircraft shall, if able:
a. Initiate a turn away from the assigned route or track before commencing the emergency descent;
b. advise the appropriate air traffic control unit as soon as possible of the emergency descent;
c. set transponder to Code 7700 and select the Emergency Mode on the automatic dependent surveillance/controller-pilot data link
communications (ADS/CPDLC) system, if applicable;
d. turn on aircraft exterior lights;
e. watch for conflicting traffic both visually and by reference to ACAS (if equipped); and
f. co-ordinate its further intentions with the appropriate ATC unit.
2.3 The aircraft should not descend below 10000 ft amsl, or Minimum Safe Altitude, whichever is the higher.
2.4 Turning-off or Remaining on Track in UK Controlled Airspace
2.4.1 UK Controlled Airspace is complex and congested; traffic is often oriented on the airway in certain directions or flows. Therefore, if
able, pilots should remain on the assigned route or track whilst carrying out the emergency descent; unless to do so otherwise would
endanger the aircraft. Notification of this preferred action in UK Controlled Airspace shall be published in the UK AIP GEN section under
PANS-ATM paragraph 15.1.4 - Emergency Descent.
2.4.2 If a turn away from an assigned route or track is initiated, pilots should note that they may not be aware of traffic in their proximity
(especially if flying on an assigned heading): nor of aircraft below them, not on the selected frequency, in adjacent airspace sectors. However,
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After reading all the wisdom spent by well educated professional pilots on this thread, may I - as a Swiss citizen - suggest (and risk) a reasonable guess ? The Swiss PIC did not have the guts to call straight away a mayday, then let his buddy on the right seat do the check-list and eventually correct his assessment of the situation.
To me, this wouldn't be an unusual cultural trait. Nothing to do with ATC, but with a typical Swiss behaviour : do not alarm the neighbourhood as long as fire is not burning your pants.
End of the story ?
To me, this wouldn't be an unusual cultural trait. Nothing to do with ATC, but with a typical Swiss behaviour : do not alarm the neighbourhood as long as fire is not burning your pants.
End of the story ?
Last edited by ettore; 20th Sep 2013 at 22:12.
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I lost auto pressurization one day in a B737, switched to standby and that didn't work so went to manual and was able to maintain pressurization. We also previously had lost the autopilot so were hand flying so when they told us to hold going into SFO from SEA told them we kind of had our hands full and holding was not a good idea so they gave us a break and let us continue our descent for landing. No need for an emergency descent in our case but we were busier than a one armed paper hangar.
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LSM et al, the UK AIP ENR section can be found here and section ENR 1.4 ATS Airspace Classification states ATC instructions are mandatory for any IFR aircraft flying in Classes A to F airspace, and any VFR aircraft flying in Class B or C airspace.
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Not sure we can lay this completely at the Swiss 'national psyche' door. It does seem that there was insufficient 'urgency' in the initial call and the 'reaction' to PAN PAN PAN is well known. I do not see anywhere what the problem was, and it appears it was not 'dramatic' enough to drop the pax masks. In any case, our checklists do imply we should try and 'solve' such a pressurisation problem at cruise level before screaming earthwards.
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TIME TO LOC WHILST ON SUPPLEMENAL O2.
Is there anyone in the aeromedical profession prepared to state how long a descent from the '40s can be delayed, if at all, with pax and crew breathing from their certificated O2 supplies, before the danger level to all increases to the stage at which it outweighs the risk of screaming earthwards, either on track as per one procedure, or turning off onto an unpredictable track as per other rules?
The skies are now so congested and LNAV so stunningly accurate, that the former on track procedure has obvious multiple targets as has the dive right/left option and the risk of losing MORE than one aircraft vastly increases.
Hell will freeze over or such a mid-air will occur, before ICAO will get around to standardising the action.
Meantime I simply ask the question, can we wait the (hopefully) short time at altitude whilst the team with the BIG picture, ATC, sorts out a suitable escape track.
I appreciate there are parts of the world where this can be accomplished better and quicker than others, but the I query the gutbusting rush which characterises the sim training for these events.
And this question is posed by an aged ex-mil poster who has done both the hypoxia and explosive decompression training in the chamber, but luckily not experienced the same in a shiny people moving tube.
I am NOT querying the necessity to aviate, navigate etc, but I am posing the subsequent decision to point the plane rapidly into almost certain danger, instead of waiting briefly for a more considered and informed option?
I now don my hard hat and await incoming fire!
The skies are now so congested and LNAV so stunningly accurate, that the former on track procedure has obvious multiple targets as has the dive right/left option and the risk of losing MORE than one aircraft vastly increases.
Hell will freeze over or such a mid-air will occur, before ICAO will get around to standardising the action.
Meantime I simply ask the question, can we wait the (hopefully) short time at altitude whilst the team with the BIG picture, ATC, sorts out a suitable escape track.
I appreciate there are parts of the world where this can be accomplished better and quicker than others, but the I query the gutbusting rush which characterises the sim training for these events.
And this question is posed by an aged ex-mil poster who has done both the hypoxia and explosive decompression training in the chamber, but luckily not experienced the same in a shiny people moving tube.
I am NOT querying the necessity to aviate, navigate etc, but I am posing the subsequent decision to point the plane rapidly into almost certain danger, instead of waiting briefly for a more considered and informed option?
I now don my hard hat and await incoming fire!
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Hi Barker - I reckon for flt crew on 100% you would have a reasonable time to make a considered judgement 'in the ??40's'??, BUT remember there are significant medical implications for the pax and c/crew with the total hypoxia time which could then ensue.
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Aviate is the key. The pilot must take action quickly to ensure the safety of his aircraft. Part of aviating is collision avoidance, so if you turn off track where national procedures suggest you don't, then you need to bear in mind that your aviating might be taking you quickly in to a previously separated opposite direction flow of traffic, or in many parts of the UK very quickly in to military danger areas where your TCAS won't show up the ordnance flying around. As with any clearance deviation, responsibility for separation moves entirely to the pilot until he communicates with ATC and an alternative is issued. How good is your situational awareness of what the airspace is either side of track and what you might encounter if you come off track ?
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MORE HASTE LESS SPEED.
"there are significant medical implications for the pax and c/crew with the total hypoxia time which could then ensue"
Agreed BOAC, which raises the question, for how long will the Chemgens supplying CC and pax keep them clear of significant and potentially damaging effects on CC mental impairment and pax discomfort?
All I'm asking is for a short "breathing space", pardon the pun, before the flight deck feel the need to dive into mid-air collision territory.
Have the aircraft makers got some sort of specification as to how well-protected CC and pax are at 41,000ft in the "NG" for example on their airmix masks?
Obviously the pilots are well catered for with 100% and emerg if selected, and they should therefore be able to operate without handicap (apart from that awful inhalation noise, which should have been engineered out BEFORE certification!) and it is this opportunity to think and communicate and then make the best decision for a downwards trajectory which I am asking to be considered.
My Noddy's Guide to the NG states the chem O2 is good for approx 12 minutes of flow, so that ensures some time to take to arrive below 15,000ft which I recall was considered a lesser hazard altitude for humans. However we have no information as to the protection offered at ceiling, and have to presume if it's good enough for CC to operate "monkey swinging" up and down the cabin, then it must be adequate for the purpose, short term?
Agreed BOAC, which raises the question, for how long will the Chemgens supplying CC and pax keep them clear of significant and potentially damaging effects on CC mental impairment and pax discomfort?
All I'm asking is for a short "breathing space", pardon the pun, before the flight deck feel the need to dive into mid-air collision territory.
Have the aircraft makers got some sort of specification as to how well-protected CC and pax are at 41,000ft in the "NG" for example on their airmix masks?
Obviously the pilots are well catered for with 100% and emerg if selected, and they should therefore be able to operate without handicap (apart from that awful inhalation noise, which should have been engineered out BEFORE certification!) and it is this opportunity to think and communicate and then make the best decision for a downwards trajectory which I am asking to be considered.
My Noddy's Guide to the NG states the chem O2 is good for approx 12 minutes of flow, so that ensures some time to take to arrive below 15,000ft which I recall was considered a lesser hazard altitude for humans. However we have no information as to the protection offered at ceiling, and have to presume if it's good enough for CC to operate "monkey swinging" up and down the cabin, then it must be adequate for the purpose, short term?
It's not always decompression. I got nailed by wake from an opposite direction 747 as I was leveling out at high altitude soon after the RVSM was implemented in the US. Shaker with a wing drop. There was no time to pause for another option.